Image formation on objective bodies

The present invention relates to image-formation on any selected kind of objective body. The characterizing features reside in such that, based upon fed image data, required images are formed on an image-transferable sheet acting for imaging carry-over service and in reliance on sublimation image transfer technique, and then, by the use of said sheet with said images thus formed thereon, the formed images thereon are transferringly applied on the objective body. By adopting the above measures, the objective body can be formed sharply and clearly with any desired images, irrespective of kind and configuration thereof, with such superior results of highly improved unity and solidability between the formed images and the objective body to be decorated with.

 

We claim:

1. A process for forming sublimation transfer images on an objective body, said process comprising:

a first transferring step for sublimation transferring images on an image-transferable sheet comprising a sheet-like substrate and an image-reception layer provided on one surface of said sheet-like substrate, said sublimation transferring being carried out by means of a thermal printer on the basis of image data formulated by an image data processor; and

a second transferring step for transferring the images formed on the image-transferable sheet from the image-transferable sheet to the objective body.

2. The process of claim 1, wherein the images are formed on an image surface of said image-reception layer by the use of a dyestuff which is capable of depositing in or on said image-transferable sheet, and then during said second transferring step, said image-reception layer of said image-tranferable sheet is caused to adhere to said objective body.

3. The process of claim 2, wherein said sheet-like substrate is a transparent film, the image surface of said image-reception layer is caused to face the body, and the image-reception layer, accompanied by the transparent film, is caused to adhere to the objective body.

4. The process of claim 2, wherein after the images are formed on the image-reception layer, the image-reception layer being separable from the sheet-like substrate, said image-reception layer is separated from said sheet-like substrate and caused to adhere to said objective body.

5. The process of claim 4, wherein the image-reception layer which has already been formed with the images is subjected provisionally to an image-transfer procedure on an intermediate transfer substrate and then, the once transferred image-reception layer is retransferred onto the objective body.

6. The method of claims 2, or wherein the step of causing the image-reception layer to adhere to said body is carried out with the use of an adhesive agent or sticking agent.

7. The process of claims 2, or wherein the step of causing the image reception layer to adhere to said body is carried out with the use of a heat bond sheet.

8. The process of claim 2, wherein the image-reception layer of the image-transfer sheet is formed with the images in positive or regular mode when viewed from the image surface of the image-reception layer.

9. The process of claim 2, wherein the image-reception layer of the image transfer sheet is formed with the images in reversed or negative mode when viewed from the image surface of said layer.

10. The process of claim 2, wherein the image-transferable sheet further comprises a protecting layer provided on one surface thereof such that said image-reception layer is separable between said protecting layer and said substrate, and said image-reception layer is subjected, together with said protecting layer, to said second transferring step.

11. The process of claim 10, wherein said protecting layer comprises a plastic film.

TECHNICAL FIELD

This invention relates to methods and apparatus for the formation of images as prints on objective bodies through transfer of images preformed by the sublimation transfer technique, and more specifically it relates to such systems as adapted for the formation of images on any selected objective body, such as cards, clothes, papers, and transparent sheets, although these are not limitative to the present invention.

BACKGROUND ART

Reliance is made generally upon the normal printing technique for formation of images on objective bodies. For the execution of the printing technique, provision and use of printing plates (forms or blocks) are requisite. No matter how simple the image-printing is, the plate-making is a very time-consuming the laborious procedure This is much more so in the printing of various and complexed image combinations, such as those of graphic or portrait images combined with characters, letters or bar codes, as an example, representing extremely complicated and troublesome work.

Further, in the normal printing operation, various operating conditions, including ink selection and the like, must be carefully considered, depending upon the kind and nature of the printing object, thus the best selection thereof is highly delicate and not as simple as expected.

The present invention is proposed upon careful consideration of the foregoing facts, and an object of the invention is to provide a unique process for the formation of sharp and clear images regardless of the kind and nature of the object to be printed upon, and usable and effective materials and apparatuses for carrying out this unique process.

The method of thermal image transfer (sublimation image transfer) on clothes or fabrics with the use of thermal transfer dyestuffs has been practiced for a long time. In this conventional process, a dyestuff picture layer carrying thermal transfer dyestuff is formed on a substrate sheet which is then subjected to heat in an overlapped state on a cloth or fabric, the dyestuff thereby being transferred thermally onto the latter for forming the desired images thereon. By utilizing this technique, and with recent development of the image forming technology concerning fine thermal printers and the like, various fine image forming processes have been proposed to provide fine images which are comparable to photographic images and are transferred onto plastic films from thermal transfer sheets carrying thermal transfer dyestuffs.

According to these recently proposed processes, various images of cameras, or TVs, graphic images of personal computers and the like can be reproduced easily in the form of hard copies on the surface of a transferred material such as a paper or the like sheet carrying thereon a fixedly attached layer of polyester resin, as an example. These images thus reproduced represent an amply high level comparable to those obtained by photography or fine printing arts.

The thermal transfer process so far set forth has an advantage in that it can form any image in a convenient manner yet entails a problem in that it is limited to image-transferred products preferably of polyester and the like materials which must be dyed with thermal transfer dyes. On the other hand, the image-transferred products must be limited to specifically selected shapes, preferably film, sheet or the like configuration, and thus, such materials as wood, metal, glass or ceramics cannot be formed with images in this way. Further, even if the material is plastics such as polyester or the like, and when the image-forming surface is curved or undulated, or physical body other than sheet, even if it represents a plane surface, it is almost impossible to reproduce images precisely thereon, which naturally constitutes a grave problem in the art.

With recent development and enlargement of utilizing fields of various card-style products, such as cash cards, telephone-cards, prepayment cards; and ID-cards, there are increasing demands for providing these cards with images, symbols and codes, so as to give various other functional and/or decorative effects. Most of these cards are of planar form, but they are frequently not pliable and/or have uneven rough portions due to provision of characters and symbols, resulting in great difficulty in the scheduled image formation relying upon the thermal image transfer process.

There is therefore an urgent demand among those skilled in the art for the provision of a unique technique capable of forming sharp and clear images of desired patterns on the surface of an objective body of any preferred kind of material and having any shape and configuration and surface condition of any kind, and indeed, for combining and unifying image- and decoration effects.

DISCLOSURE OF THE INVENTION

The present invention is basically based on such a principle that a first image transfer pattern is formed on an image transfer material, preferably an image transfer sheet, and in the form of dyestuff images through the sublimation image transfer process executed by first image transfer means, depending upon given image data, preferably including those of letters, characters, symbols, line images, graduated graphic representations, and then the first transfer pattern is transferred to second transfer means for retransferring the images onto an objective body so as to provide a final product.

Based upon the image data fed from various image data input means and at the first image-transfer means, a thermal head is actuated to execute printing operation through a dyestuff film (thermal image-transfer sheet) on an image-transfer material (or more specifically on an image-transferable material which means an image-transferable sheet. This image-printing is carried out according to the sublimation or sublimative image transfer technique. Thus, in this case, the dyestuff on the dyestuff film is transferred or shifted under the influence of heat energy from the thermal head onto the image-transfer material through sublimation, thus providing the first image-transferred means. Since this first image-transferred means has been thus formed with the images by the sublimated dyestuff, they are, then, transferred onto the second image-transferable means which will be brought into tight contact with the object to be decorated and subjected to heat and pressure for execution of further image-transfer operation to provide the final desired product.

In the present invention, the image-transfer material (image-transferable sheet) is, as above referred to, formed with images by the sublimative image transfer technique for providing first image-transfer means which has highly sharp and clear images a the operation and results of the characterizing feature of the sublimation image-transfer technique. Therefore, because of the transfer of such sharp and clear images onto the object, it becomes possible to form the images thereon, and indeed, practically irrespective of the kind and nature of the object. In this way, thus, fine image-formation is assured onto practically any objective substance.

And further, by execution of control of the thermal energy applied during the sublimative image-transfer step, the resulting color effect is superior and the image quality is good.

The images sublimatingly applied and formed in the foregoing way are subjected to a further transfer, and onto a substrate product, for providing a final decorative product as desired. In this final product, it should be noted that the underlying layer underneath the images during the sublimative image-transfer stage appears now at the top, acting thus as a kind of protecting layer upon up-and-down positional conversion during execution of the second and final image transfer stage, resulting in realization of various and numerous effects. As an example, attainment of substantial reduction of contamination, improvement of light resistance, weather resistance and chemical resistance; substantial reduction of color fading; provision of glazing effect; easier and simpler introduction of granular and/or undulated image appearance.

The inventive process is carried into effect basically in such a manner that an image-reception layer provided on one surface of an image-transferable sheet is subjected to an image-forming step with the use of dyestuff capable of depositing therein depending upon the fed image data, so as to form the required images, and then, the image-reception layer of the image transferable sheet, having been image-fixed and thus now image-carrying, is stuck onto the surface of the object to be decorated upon.

As for the image-transferable sheet adapted for use in the image-transfer during execution of the inventive process, it consists basically of a sheet-like substrate and a reception layer attached, however, in a separable manner, onto one surface thereof. As a modification of the inventive process from the basic mode set forth above, the sheet-like substrate is caused to remain, even after completion of the image-transfer step, as may be occasionally required. In this modified case, it is unnecessary to make the image-reception layer of the image transfer sheet separable.

Under occasion, the inventive process may be brought into effect in such a wa that the image-reception layer of the image-transfer sheet is transferred upon execution of the image-forming step, and indeed, once onto an intermediate image-transfer substrate which is then retransferred, together with the once transferred image-reception layer, onto the surface of an object to be decorated on, and thus, in a retransferring manner.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1A is a block diagram, showing a preferred embodiment of the apparatus according to the present invention;

FIG. 1B is a schematic view illustrating at (a), (b) and (c), several image-transfer steps for the execution of a process according to the invention;

FIG. 1C is a schematic view of an image-transfer step, using a platen roll;

FIG. 1D is a plan view of part of a multi-color dyestuff film adapted for use in an image-forming step;

FIG. 1E is a schematic view for the illustration of several image-transfer steps;

FIG. 2 is a flow chart of successive operation steps with use of a data-processor, shown in FIG. 1, functioning as an operating center;

FIG. 3A is a schematic block diagram, showing a data-processor for the printer;

FIG. 3B is a block diagram of a sublimative image-transferring printer adopted in the present invention, as a preferred embodiment thereof;

FIG. 4 is a schematic block diagram, showing a color correction unit shown in FIG. 3A, and several related parts cooperating therewith;

FIG. 5 is a schematic block diagram of a comparator and several related parts cooperating therewith;

FIG. 6 is a circuit block diagram of an image-transfer head shown in FIG. 1B;

FIG. 7 is a graph showing operational characteristics of a color tone or -gradation corrector unit shown in FIG. 3A;

FIG. 8 is a table for the illustration, as an example, of picture- or image-elements, as expressed in binary signals;

FIG. 9 is a table showing a conversion operation, as an example, of a parallel/series converter shown in FIG. 3A;

FIG. 10 is a flow chart, illustrating the operation of the sublimative image transfer printer;

FIG. 11 is a plan view of a final decorative product prepared according to the inventive technique;

FIG. 12 is a sectional view of the product card shown in FIG. 11, and taken along a section line A--A shown therein;

FIGS. 13 through 31 are a series of sectional views, respectively illustrating several structural examples of image-transferable sheets, suitable for use in the invention; and

FIGS. 32 (a), (b), and (c) are sectional views, indicating final transfer steps.

BEST MODES FOR CARRYING OUT THE INVENTION

Referring now to FIG. 1A and FIG. 1B, (a), (b) and (c), a basic scheme of the inventive image data processing and image formation will be illustrated. First, in FIG. 1A, numeral 101 represents an image input means which is adapted for forming image data based upon optical and the like inputs delivered from a TV-camera, line sensor or the like. Other than those above enlisted only by way of example, video; CD; TV; scanner; personal computer, captain system, capable of providing R.G.B.- and picture image and the like signals may also be utilized in a similar way. The image signal data delivered from the image input means are fed through a data processor 104 to a memory 105 for being stored therein. These stored data can be taken out from the memory and fed through data processor 104 to display means 102 for being displayed thereat.

To the data processer 104, a mouth/tablet digitizer and/or the like position data processer 103 is electrically connected for introducing position data concerning displayed images appearing at the display 102. In addition, key board and the like character data input means 106 and font generator 109 are provided for introducing character data. Still further, a barcode generator 110 is provided for introducing barcode when necessary. By the use of these means and units, various additional processing modes can be executed.

The thus processed data are subjected to conversion at a data converter 107 into proper data adapted for operating a sublimation transfer printer and fed forward through a driver 108 to the thermal head.

In this case, by controlling the current duration period to the thermal element of the thermal head, the transfer quantity from the dyestuff film (thermal transfer sheet) is controlled depending upon the thermal energy of the element for realization of the desired gradation degree of concentration on the transfer sheet. There are two different modes of such control of current duration period as follows:

(a) A method for controlling the pulse length corresponding to the picture element in the impressed data to the thermal element of the thermal head or, more specifically, a series data introduced as input to the shift register shown in FIG. 6 and to be described more specifically hereinafter.

(b) A method for controlling the number of pulses of the pulse series corresponding to the picture elements of the data impressed upon the thermal element in the thermal head (in this case, the pulse length being constant).

The degree of gradation of the transfer image can be controlled in the above mentioned way by the regulation of the current-conducting period depending upon the desired gradation degree. On the other hand, the image concentration can be controlled by adjusting the pulse length or the number of pulses contained in the pulse series in correspondence to the picture elements contained in the data as introduced in the shift register and depending upon the driving mode of the thermal head. Further in this case, if the number of gradation of introduced image data is larger than that which can be expressed by the printer unit, a proper conversion operation can be performed by the known strobe control method As an example, in such case, the conversion of gradation number 256 to 64 may be executed by a ROM, and the thus reduced gradation number can be used as output.

Next, referring to FIG. 1B at (a) and (b), reference numeral 121 represents a thermal head which receives signals from the driver 108 shown in FIG. 1A. This thermal head 121 is arranged in opposition to platen roll 122, forming the printing position therebetween. The dyestuff film (thermal transfer sheet) is fed from a delivery roll 123 to a winding roll 124 through this printing position, these structural and functional features being commonly employed in both the arrangements shown in FIG. 1B at (a) and (b).

In the case of FIG. 1B, (a), the mechanism is so arranged that card or sheet style transfer sheets are printed with dyestuff images.

On the other hand, in the case of FIG. 1B, (b), the mechanism is so arranged that cards are continuously produced with the use of a film style transfer sheet and a dyestuff film in combination.

Now turning back to FIG. 1B, (a), a number of transfer sheets (cards, sheets or the like) have been stacked and stored within a storage casing 125 and ar being thrust upward from below by a spring so that the uppermost sheet is kept in pressure contact with a take-out roll 126. With the rotation of the roll 126, the sheets are successively delivered from the casing 125 by conveyer belts 127, 128 onto a platen roll 122. Each one of the sheets is fixed on the peripheral surface of the platen roll, now positionally indexed, by means of a gripper or the like mechanical attaching and separating means, static attracting means, or electromagnetic attaching means. Then, the roll 122 is so rotated that the transfer sheet is positioned at the ready-for-printing-position.

Next, the thermal head 121 is brought into pressure contact with the transfer sheet through the intermediary of the dyestuff film, and then the thermal head 121 is energized with electric current while the dyestuff film and platen roll 122 are moved in synchronism for the execution of image transfer (first image transfer).

Upon execution of the image transfer, the platen roll 122 is rotated, the gripper is released and the take-out roll 129 is rotated and brought into pressure contact for taking out the image transfer sheet onto a tray 130.

The thus taken out sheet is brought into overlapped state with a new image transfer sheet, not shown, and then, both the sheets are fusingly united together by pressure application of a heated roll, not shown, for execution of a second transfer step job. The whole operation has thus been completed. Before the fusion process, the sheets may be subjected to punching, trimming and/or the like processing, if necessary.

By execution of the foregoing operational steps, a monocolor printing operation has been completed. However, in the case of multicolor printing, use is made of tricolored or quadruple colored dyestuff film and the corresponding printing operations must be repeated. In this case, upon completion of a single monocolor printing procedure, the platen roll is rotated without contact of the take-out roll 129, until it arrives again at the printing-initiation position, and so on.

In the following, a tricolor printing job will be illustrated with reference to FIG. 1B, (b), and with use of three different series color zones, of cyan, magenta and yellow.

First, a platen roll 122 is positionally indexed, and an image transfer sheet taken out from the roll 131 and a dyestuff film taken out from the roll 123 are brought into pressure contact in an overlapped state. Then a thermal head 121 is pressed against the platen roll 122 through the intermediary of the overlapped sheets. At this stage, the platen roll 122 is rotated counterclockwise while synchronism is kept between the platen roll 122 and the dyestuff film, and the thermal head 121 is kept electrically energized. In this way, the first color printing is executed.

Further, the dyestuff film is fed to the second color zone position, and then, the platen roll 122, the dyestuff film and the image transfer sheet are fed forward clockwise around the center roll 122. Thus a second color printing step is executed.

Further, the print-serviced two color sections of the film is fed back counter clockwise around the center of the platen roll 122 for the execution of a third color printing step. Then, each card sheet is taken out from the stack 200 under the action of take-out rolls or the like, not shown, towards and between a pair of thermal transfer rolls 132, 133, brought into overlapping state with the image transfer sheet positionally indexed and already subjected to image transfer steps as was described above, and finally subjected to a picture printing operation by pressurizing application of the thermal image transfer rolls 132, 133 from both sides of each taken-out card, and so on.

The color-printing step with the use of the thermal head is carried into effect in the following manner, as an example.

(First color printing)

Platen roll, image transfer sheet and dyestuff film perform the printing while they are moved in the counterclockwise direction.

(Second color printing)

Platen roll and image transfer sheet are moved in the clockwise direction while the dyestuff film is moved at the same speed and in the counterclockwise direction for performing the color printing under consideration.

(Third color printing)

Platen roll, image transfer sheet and dyestuff film are moved in the counterclockwise direction for execution of the color printing under consideration.

In the modified arrangement shown in FIG. 1B, (c), thermal image transfer rolls 132, 133 have been replaced by a flat press type image transfer head having up-and-down movable flat printer elements 132', 133'.

It should be noted that in the course of the foregoing first and second image transfer steps, image reversal phenomenon is necessarily brought about upon execution of each image transfer step. In other words and more specifically, when two successive image transfer steps in the foregoing sense are executed, reverse images which have once appeared will return to the original normal images. Therefore, when the printed-out products are to be provided upon execution of the first image transfer step, it is necessary to provide reversed image data in the signal processing system. For this purpose, it is only necessary to reverse the addressing order at the data introduction or readout stage into or from the memory.

In the modified arrangement shown in FIG. 1C, the foregoing platen roll means has been replaced by a metal block 141 lined with a rubber plate 142 in an overlapped manner. The image transfer sheet and dyestuff film are fed out from respective rolls 131 and 123. With the use of this modified arrangement, the dyestuff surface layer of the dyestuff film can be brought into tight contact with the image-receiving surface layer of the image transfer sheet, and thermal energy will be transferred evenly form the thermal head 121 to the dyestuff, film.

In this case, the image transfer sheet is delivered from the roll 131, and the desired zone or region of the sheet is set underneath the rubber plate 142 (step 1).

At the same time, the dyestuff film shown in FIG. 1D on an enlarged scale is delivered from the roll 123 and a selected one of the different color regions is set underneath the rubber plate 142 (step 2).

Next, the thermal head 121 is brought into the rear surface of the dyestuff film which is the opposite surface to the dyestuff-coated front layer, and the head 121 is driven while it is being translated in the direction shown by an arrow A, images thereby being formed at the specifically allocated zone(s) or region(s) of the image transfer sheet (step 3).

Further, the thermal head 121 and rolls 416 and 418 are shifted downwards as shown by arrows B, so as to form an idle gap between the image transfer sheet and the dyestuff film for allowing the latter to shift towards the next following color region (step 4).

Further, the thermal head 121 and rolls 416 and 418 are returned to their original positions, whereupon the third and further succeeding steps are repeatedly executed until a certain predesired number of color printings are completed.

As shown in FIG. 1D, the dyestuff film is colored to have several different color regions denoted by Y (yellow), M (magenta), C (cyan) and Bk (black). However, the arrangement order is not limited to that shown: Y; M; C and Bk. In addition, as occasionally required, the Bk-region may be dispensed with. Further, as the color elements to be adopted in the Y, M, C-system may not be limited to the three primary colors provided by the subtractive color mixture. On occasion, a characterizing color which means such a color as preadjusted to provide an objective specifically selected one may be used to form the images concerned. As a further modification, the arrangement shown in FIG. 1C may be so modified that the traveling direction of the image transfer sheet is selected to be perpendicular to that of the dyestuff film.

FIG. 2 is an operation flow chart for showing schematically operational modes taking the data processor 104 adopted in the embodiment shown in FIG. 1 as the centrum of description. The operational contents of several working parts downstream of the data converter 107 will be set forth separately hereinbelow. Now referring to FIG. 2, in combination with FIG. 1 and at the step of S101, image pickup operation is carried out by means of the image pickup means 101. For execution of this step, it may be better to pick up the face of a person per se which is to be represented on the card, or alternatively, a photograph, portrait or imagery product thereof will do. Depending upon the nature of the object, a TV camera, line sensor or the like instrument may naturally be selectively utilized.

The data taken by the image pickup means 101 are stored through the data processor 104 at a memory 105 (S102). By the use of these stored data, image or images is/are displayed at the display 102 (S103). Since this display image is not yet subjected to any processing, it is generally unsuitable for representing on the card. However, under certain circumstances, it may be represented thereon as it is.

Then, the operator observed the displayed image or images on the display unit 102 and adjudges whether additional processing is necessary or not (S104). If it is not necessary, he will manipulate the key board 106 to make a certain operation, resulting in the termination of processing at the data processing unit 104, data being fed out therefrom to the succeeding data converter 107.

On the contrary, when additional processing is necessary, the operator observes carefully the displayed image or images on the unit 102 and adjudges whether the picture image data, or character data or barcode data should be processed. If the picture image data should be processed, such an operation is made for selecting the proper mass of trimming or layout within the menu range of position-data input means 103. By the execution of this operation, functions and operations at steps S105 and S106 can be executed at one stroke. If trimming is taken as an example, the next step is executed in such a way that position data are fed from the position input means 103 to the data-processer 104 with the use of a carsor. When a tablet digitizer is used as the position data input means, the carsor image displayed in an overlapped manner on the displayed picture image appearing at the display unit 102 by carsor manipulation is positionally specified beforehand in registration with the specified position on the card, for determining the trimming range. Then the operation is carried out in such a way that the picture image data outside the specified trimming range are canceled. By completing these operations, data processing operations relating to step 107 are executed, and, then, the mass for completion of the menu range is selected out. By these measures, steps progress through S109 to S102, and data storing is executed, and further, display representation is brought about through step S103. If there is no need for additional processing, an operation termination manipulation is carried out as before at key board 106, and further operations will be made through data converter 107.

As for the layout, the operation is carried out with the position data input means 103, similarly as in the foregoing trimming operation. More specifically, layout is selected out in the menu range of position data input means 103, and the overall configuration of the card and the display position of picture image are shown at display unit 102. Then, image inclination correcting operation and the like are carried out so as to realize correspondence thereof with the displayed positional information, the processing operations relating to step S108 thereby being brought about. After completion of these operations, the mass for the ending in the menu range is selected.

In this way, when selection is made from the menu range by reliance on the position data input means 103, trimming or layout operation can be brought about. At this stage, when manual operation is carried out at the key board 106, introduction of character data is executed (S110). As the character data in this sense, in the case of ID card, as an example, the name and/or birthday, month and year of the owner may be used. The data introduced from the key board 106 in accordance with the output character style from the font generator 109 are shown at the display unit 102 in the specified positions on the displaying surface and respectively arranged in accordance with display items. The operator acknowledges these items and detailed displays of the represented images. When he acknowledges them as being true, he will operate the key board 106 for showing the operation ending (S111).

Upon ending the operations as described above, the data are stored in memory 105 (S102) and represented at the display 102. The operator will acknowledge again this fact, and upon the execution of this, the operations are terminated.

As for the barcode introduction, the data are subjected to inputing at steps S112 and S113, as in a manner similar to the character data introduction as set forth above. The barcodes and the like data may be introduced separately through printing or other mechanical method.

In FIG. 3A, a data processing circuitry usable in the sublimation image transfer printing method is shown only schematically. As shown, the circuitry 107 comprises a picture element density converter 3; a color corrector 4; a gradation corrector 10; a memory 11; a switch 12; a buffer 13 and parallel/series converter 14. The picture element density converter 3 is connected to a picture image input unit 100.

The unit 100 serves for generation of three primary color data of R.G.B.- or Y.M.C.-mode from original picture images and is connected through the picture element density converter 3 to the color corrector 4. The converter 3 converts the picture element density of the image data fed from the unit 100 to the desired one, by subtracting or supplementing, as the case may be, image data for each color element. It should be mentioned that for attaining high quality hard copies, conversion of the picture element density to at least 10 lines/mm or so is preferable.

Color corrector 4 consists preferably of a color decoder, level adjuster or color converter, and serves to correct three primary color data converted to those of a predetermined density of picture elements in consideration of characteristics of the image transfer ink in the image transfer sheet and in addition to provide black color data.

The data processing circuitry 107 is connected through a driver 108 to the sublimation image transfer printer.

In FIG. 4, an example of the color corrector 4 is shown schematically in structure. As shown, it comprises adders 6Y; 6M and 6C, a black color data calculator 7, and primary and secondary color correction circuits 8 and 9. Primary color correction circuit 8 serves for making correction of turbidity of the image transfer ink, while secondary color correction circuit 9 provides a capability of arbitrary and selective correction control relative to specifically selected color hue.

The gradation corrector 10 is so arranged as to make correction of the gradation of the data for each color Y, M, C or K (representing black color) fed from the foregoing color corrector 4 when necessary. For this purpose, the corrector 10 includes a gradation circuit (not shown) and the like, whereby a certain mode of highlight stressing or shadow stressing is introduced and realized.

The memory 11 functions to preserve temporarily the data of each color delivered from the gradation corrector 10, a selection switch 12 being provided at the output side of the memory for selective writing-in of the data of each color to the buffer 13. The buffer 13 is capable of writing-in the data of one line of the image transfer head 16 and kept in connection with the parallel/series converter 14 adapted for converting parallel data into series data. Additionally, in the simplified machine, black color data series is dispensed with in some instances.

In FIG. 5, a schematic construction of the parallel/series converter 14 is shown. As shown, parallel data delivered from the buffer 13 are fed to an input side of a comparator 22, while outputs from a counter 23 are fed to another input side of the comparator 22 which delivers the converted series data to the driver 15 for driving a thermal head 121.

If necessary, however, the comparator 22 may be replaced by a converter table, not shown, utilizing a parallel/series converting ROM.

In FIG. 6, a detailed circuit scheme of the thermal head 121 is shown. As shown, series data delivered from the comparator 22 are fed into a shift register SR and thence, after being subjected to latching at a latch circuit LT, fed to thermal elements HE through NAND gates NA which are fed at respective one side inlets with strobe signals.

Next, referring to FIG. 3A, the operation of the data processing circuitry 107 will be described more specifically.

First, when three primary color image data are fed from the picture image inlet circuit 100 to the picture element density converter 3, the latter converts these three primary color data to those which represent a predetermined picture element density and then are fed to the color correction unit 4. In this case, it is assumed that the unit 4 is fed with three primary color data expressed in respective concentration signals, which are of yellow: Y0; of magenta: M0 and of cyan: C0, respectively, in the present example.

These data: Y0; M0 and C0 are, as shown in FIG. 4, fed through respective adders 6Y; 6M and 6C to the black color data calculator 7, to provide a K-output as expressed mathematically by the following formula:

K=min (Y, M, C)

wherein, "min" represents a function which provides a possible minimum value.

These data: Y0, M0 and C0 are fed from the converter 3 to the primary color correction circuit 8 to provide primarily corrected data Y1, M1 and C1 which are thence fed to the secondary color correction circuit 9 to provide, through calculation, secondarily corrected data: Y2, M2 and C2, respectively. These are then fed to respective adders 6Y, 6M and 6C, which add them to respective data Y0, M0 and C0, to provide respectively added output data Y, M, and C to be fed to the gradation correcter circuit 10, respectively, after being utilized for calculation of the K-output signal value.

The primary color correction circuit 8 serves to calculate primarily corrected data: Y1, M1 and C1 which are necessarily utilized for correct-out of transfer ink turbit. In this case, the original data: Y0, M0 and C0 are subjected to matrix calculation to provide the primarily corrected data Y1, M1 and C1, as follows:

Y1=k.sub.11.C0-k.sub.12.M0+k.sub.13.Y0

M1=k.sub.21.C0+k.sub.22.M0-k.sub.23.Y0

C1=k.sub.31.C0+k.sub.32.M0-k.sub.33.Y0

Where, k.sub.ij represents weight coefficients:

i=1-3; and

j=1-3.

The secondary color correction circuit 9 serves to calculate secondary color correction data Y2, M2 and C2 from primary color correction data Y1, M1 and C1 by modifying the latter to make certain thereto by performing matrix calculations so as to provide a capability for making an arbitral and selective color control at a certain specifically selected-out color hue, in the following manner: ##EQU1## wherein, l.sub.ij represents weight coefficients:

i=1-3;

j=1-6;

.DELTA.B, .DELTA.C, .DELTA.G, .DELTA.Y, .DELTA.R, .DELTA.M:

characterizing color data.

Thus, when these secondary correction data Y2, M2 and C2 are added to the corresponding original data Y0, M0 and C0 by means of respective adders 6Y, 6M and 6C and under proper selection of weight coefficients k.sub.ij for primary color correction circuit 8, any color discrepancy of the ideal color of the ink appearing on the printed picture images under the action of the sublimation transfer printer can be arbitrarily ammended. In this case, when the weight coefficients l.sub.ij for the secondary correction circuit 9 are selected out properly, the color tone of the printing picture images can be modified to an arbitrary degree.

Further, as for the black color data K, correction data K2 can be calculated by the following formula. With use of these correction data K2, which are added to the original black color data K, the desired correction can be executed in a similar manner.

K2=K+ml..DELTA.B+m2..DELTA.C+m3..DELTA.G+m4.

.DELTA.Y+m5..DELTA.R+m6. .DELTA.M

wherein, Mi represents weight coefficients:

i=1--6.

In this way, output data: Y, M, C and K delivered from the color correction circuit 4 are introduced into the gradation corrector 10 as inputs thereof, and each constituent of these data can be subjected to correction as desired.

FIG. 7 shows several characteristic curves illustrating corrections by means of the gradation corrector 10. More specifically, f0 represents a standard characteristic curve; f1 a highlight stressing operation curve; f2 a shadow-stressing operation curve; f3 a highlight-and-shadow stressing operation curve; and f4 a medium tone stressing operation curve.

As indicated in FIG. 7, by presetting, as necessary, the tone-reproducing characteristics, which determine the relationship between that concentration of color data and that of the prints printed by means of a sublimation image transferring printer, a color tone similar to that possessed by the original image can be reproduced. More specifically, when no correction is adopted, the curve f0 is used, while in the case of correction, any selected one of these curves f1 to f4 may be utilized depending upon the part of gradation to be stressed. Further, it should be noted that the tone reproducing characteristic curves are not exclusively limited to those which have been specifically shown and described above. As an example, the control of gradation correction by color tone reproducing characteristic mentioned above is executed by a gradation circuit, not shown, and the setting of the color tone reproducing characteristic is brought about by manipulation of any selected one of the control knobs, not shown, which are provided separately for "highlight"; "medium tone" and "shadow".

Y.M C K. data subjected to correction by the gradation corrector 10 are once stored in the memory unit 11. The thus stored data may be read out from the memory for each color by manipulation of the selection switch 12 and, after provisional storing, per one line of transfer head 16, at the buffer 13, introduced into the parallel/series converter 14 for conversion thereby into corresponding series data.

Another example of the data processing circuit for the sublimation transfer printer is shown only schematically in FIG. 3B. As shown, the processing circuit in 107' comprises a level regulator 503; a color converter 504; an A/D converter 505 and a parallel/series converter 14.

As the image data introduced into the processing circuit 107', those which have been subjected to conversion into R.G.B.-signals in the color decoder 502 from composite video signals delivered from a T.V. camera, VTR or the like are used. On the other hand, R.G.B.-signals delivered from a personal computer, captain system or the like means are introduced as input into the level adjuster 503.

As the color correction method with the use of the foregoing arrangements, it is possible, more specifically, to adjust the hue saturation and/or brightness in the color decoder 502, or to adjust the signal level of each color light of R.G.B.-system in the level regulator 503.

As an example, the color conversion from R.G.B.- to Y.M.C.-system can be executed in the color converter 504. The simplest possible method in this color conversion is to procure the opposite color to each of the normal colors.

The thus produced color signals of Y.M.C.-system is subjected to A/D conversion and then fed successively through the parallel/series converter 14 and the driver 108 to the thermal head, not shown, to carry out printing in the sublimation transfer principle.

Additionally, in normal cases, with the use of the foregoing system composition, input image data must be of static mode. However, by provision of memory means in front of the color decoder or at an intermediate position between the A/D converter and parallel/series converter, animating images can be processed.

The series data converted in the foregoing manner in the data converter 107 or 107' are fed to the shift register SR shown in FIG. 6 by n-image elements and then, upon being subjected to latching in the latch circuit LT are further delivered to NAND gate NA as its inputs. When a strobe signal ST is fed as input to the NAND gate NA, the foregoing n-image element data is fed to the thermal element HE.

FIG. 8 is a schematic diagram, showing signals for respective image elements. The gradation has been so selected that the first image element is at the highest gradation level, while the n-th image element corresponds to the lowest gradation level, and that the second to (n-1)th image elements vary linearly in gradation levels, so as to provide representatively a better understandable example of the invention.

Next, the operation of the parallel/series converter 14 will be described.

First, as shown in FIG. 5, image elements data A, consisting of parallel data, more specifically, comprising parallel eight bit data A0-A7, are fed to one-side inputs of comparator 22, while another side inputs thereof are fed with outputs B, comprising eight bit increment outputs B0-B7, of counter 23. The counter 23 counts clock signals in increments, the outputs B0-B7 being successively varied.

The comparator 22 performs comparison between the two inputs A and B, so as to deliver successively outputs of binary "1" until the increment output B is brought into coincidence with image elements data A, or more specifically, under the condition of A>B and A=B, while, thereafter, binary "0"-outputs are delivered therefrom. More specifically, comparator 22 will continue to deliver binary "1" until an increment value which corresponds to the weight of concentration of image element data A is given thereto. As an example, if the image element data A has a concentration of gradation 128 of a total 256, output "1" will be repeated to deliver 128 times first and then, output "0" will follow after again 128 times, so as to provide in total a specific series data peculiarly in this case.

These series data are taken out from the comparator 22 in the form of A>B- and A.gtoreq.B-outputs and of A=B-outputs through an attributed OR-gate 24, and in the present example, the gradation consists of 256 steps or increments. However, in practice, the gradation may represent a smaller number of steps. As an example, if the incrementing bit is B1 instead of hitherto employed B0, the gradation will have 128 steps; and if B2 is employed, it will have only 64 steps. In this way, the gradation setting may be varied in a simple manner.

When in the foregoing way, the output B from the counter 23 is stepwise incremented, such series data consisting of a first series of "1" will be delivered until the relationship between the image elements data A and the output B from counter 23 becomes A=B, and of a second series of "0" issued thereafter, as shown in FIG. 8.

In FIG. 9, a conversion mode at the parallel/series converter 14, which, however, is different from that shown in FIG. 8, as an example, is shown again in the form of a matrix. As shown, when the image data are of 8-bit parallel kind, as an example, the gradation data are ranged from 0 to 255, providing, therefore, binary series data from "00 . . . 00" to "11 . . . 11".

In this way, the data, per line in the transfer head 16, kept preserved in the buffer 13 are fed to the parallel/series converter 14 for providing as outputs therefrom into corresponding series data which are then delivered through the driver 15 to the transfer head 16 and thus recorded on a print paper P supported on the transfer drum 17.

FIG. 10 represents a flow chart illustrating the operation of the sublimate printer as employed in the present invention.

At the first step S1, print papers are set in position and the printing ribbon is also set in position ready for performing the required procedure.

At the second step S2, printing operation is initiated, and line printings are executed, line by line, accompanying necessary intermittent line shifts, with relation to any selected one of four colors: C (cyan); M (magenta); Y (yellow) and K (black) being carried out. Refer to S3 and S4. When line printings with the selected-out single color have been completed (S5), the image transfer sheet is replaced by another color sheet (S6) and so on. In this way, line printings are completed in all four colors. In this case it is naturally most preferable to use a long extended single transfer sheet on which four color ink regions are repeatedly printed in a certain predetermined pattern. The image reception paper is initiated to make print from a certain prescribed position for each of these colors (S8). When all of the printing steps have been completed with the four colors, the paper is discharged from position (S9) and the printing operation is terminated to be repeated.

In FIG. 11, a card style sample of the final products according to this invention is shown in front view at 200. FIG. 12 is a sectional view thereof. Numeral 201 represents the substrate material of the card; 202 a display layer; 203 a surface protecting layer; and 204 a display image as an example. Depending upon the kind of usage and when necessary, the protecting layer 203 may be dispensed with. It should be noted that the display image 204 on the display layer 202 is represented by a sublimative dyestuff, as a characterizing feature of the present invention.

As the main and substantial material of the image transfer sheet, various plain papers, converted papers, plastic resin sheets or the like may be used per se or in combination. When a plastic resin sheet which can be colored directly with a sublimative dye or dyes is used, these image transfer substrates (articles or objects) as at 201 can be united each with the display layer 202. Each of these substrate materials, when it is of the card style, may have generally such dimensions: thickness of 0.68 to 0.80 mm and size: 11 to 8.times.8 to 5 cm.

As the material of the display layer 202, various known materials which may be colored with sublimative dyestuffs, such as polyethylene, polypropylene, polyester, ABS, AS, polyvinylchloride, polyvinyl/vinyl acetate copolymer, polystyrene, polyacrylate, polyester, polyamide, polyurethane and the like plastic material, may be advantageously utilized. As will be more specifically described hereinafter, this material layer can be united with the substrate material layer 201. In the case of such unified structure with substrate layer 201, the thickness and size dimensions may be substantially as the same as before. However, when normal and/or converted papers or metals, which are practically impossible to color with sublimative dyestuffs, are used as the substrate layer 201, various methods can be utilized for desired coloring. As an example, a solution including at least any selected one of plastic resin materials capable of coloring with sublimative dyestuffs may be coated on the substrate surface, or alternatively used in the form of a film which is laminated thereon. This kind of film preferably has a thickness of about 3 to 50 .mu.m or so. One of main characterizing features represented in and by the final products 200 is that the appearing display image or images as at 204 is/are formed at least partially or wholly with a sublimative dyestuff or dyestuffs. Additionally, the process for formation of such images can be executed in the conventional art.

As an example, the processing method may be executed conventionally as follows.

As an example, a sublimative image transferable sheet, such as a paper sheet, plastic resin film or sheet capable of acting as the carrier is coated on its surface with any suitable binder resin carrier carrying sublimative a dyestuff or dyestuffs under heat, is overlapped on the display layer 202 and then subjected to heat from behind the heat-transferable sheet, preferably in the pattern mode, so as to transfer the dyestuff or dyestuffs into the display layer 202. It is proper to select the molecular weight of 250 or larger of the dyestuff, for improving the fastness thereof. However, a molecular weight higher than 370 is more favorable. In the case of provision of the surface protecting layer, there is practically no limitation to the selectability of the dyestuff molecular weight.

The sublimative image transfer may be executed directly on the surface of substrate 201 provided with the display layer 202. Or alternatively, a carrying, image transferable sheet is prepared separately and, after formation of the image 204 thereon, may be stuck onto or laminated on the substrate 201.

Image-carrying and imaqe-transferable sheet

In the following, structure, material, usage and application purpose of the image transferable sheet to be employed in the present invention will be described in detail:

FIG. 13 illustrates only basically and in schematic sectional view the image-transferable sheet adopted in the present invention, while FIGS. 14 through 19 and 22 through 24 illustrate preferable embodiments thereof.

The basic structure of the image transferable sheet 310 is characterized in that, as shown in FIG. 13, a sheet-like substrate 301 is provided at its one surface with an image-reception layer 302 capable of peel-off from the substrate. By adopting such a structural configuration of the image-transferable sheet, the image-reception layer 302 can be formed with the required image or images with the use of an image transferable sheet having thermally shiftable dyestuff, and then, the image-formed, image-reception layer 302 is peeled off from substrate 301 and attached firmly, preferably as by sticking, on the surface of any selected object or article with use of any suitable means. In this way, various conventional drawbacks inherent in the comparative conventional technique can be basically overcome.

More specifically, as the material of the aforementioned image reception layer 302, limitation must be imposed to those which can be colored with thermally shiftable or transferable dyestuff. However, upon formation of necessary images and upon peel-off from the sheet like substrate 301, the image reception layer 302 may be attached fixedly onto the surface of glass-made, metal-made or wooden-made products or plastic-resin made ones which are very difficult to color with thermally shiftable and transferable dyestuffs, indeed, by reliance on conventional sticking techniques as properly adopted in consideration of the specific nature and kind of the material of decorative products to be ornamented. Further, the image-formed and peeled-off, image-reception layer 302 from the sheet substrate 301, is highly thin and thus sufficiently pliable so that it may be applied even onto any uneven and complicated surface of a product to be decorated or ornamented, having undulations, convexities, concavities, recesses and projections. Therefore, a maximum possible better fitness of the image-reception layer to be ornamented is attained and guaranteed by the present invention. Thus, practically no limitation in the attaching use thereof may be encountered. Further, in sharp contrast to conventional sealing seals and the like, the very thin image-reception layer bearing necessary images can be applied easily to the product per se in a very uniform manner, thus providing no raised and thickened feeling, and giving rise to no foreign feeling upon attachment.

FIG. 14 shows a further example of the image transferable sheet 310. In this case, there is provided a parting agent layer 303 on the surface of image-reception layer 302. Between the latter and the sheet substrate 301, there is provided a parting agent layer 303'. If necessary, however, any one of the two layers 303; 303' may be dispensed with.

The first parting agent layer 303 is provided for prevention of thermal fusion between the image-reception layer 302 and an image transferable sheet, not shown, as may occur during image transfer and formation on the first layer 302 through transfer of thermally transferable dyestuff from the said transferable sheet to the first layer. If there is no risk of such thermal fusion of the above nature, or when the image-transferable sheet has been already provided with such a parting agent layer, the present provision thereof may be unnecessary. As for another parting agent layer 303', it is for the purpose of making the latter peel-off operation, to be executed after image-forming step, easier. When the sheet-like substrate 301 is made of polyester or the like material which has, as it is, sufficient separability from image-reception layer 302, provision of parting agent layer may naturally be dispensed with.

FIG. 15 illustrates a still further example of image transferable sheet 310. In this case, between the image-reception 302 and the sheet-like substrate 301, an intermediate layer 304 and/or parting agent layer 303' is/are provided. The laminating order is optional and thus not binding. The intermediate layer 304 will serve to assist the image formation to be rather firm and beautiful, the image formation being carried out by transferring the thermally shifting and transferring dyestuff from the image transferable sheet to the image-reception layer 302. For this purpose, the intermediate layer 304 may take, for example, the form of a cushioning layer or heat insulating layer. When a cushioning layer is provided as the intermediate layer 304, the cohesion between the image transferable sheet and th image reception layer 302 is greatly improved and the thermal shift and transfer of the dyestuff during image formation with the use of a thermal head is evenly executed, the image formation thereby being carried out amply in correspondence with the supplied image signals. Further, when a heat insulating layer consisting of a highly heat-insulative material is used as the intermediate layer 304, ineffective release of the heat applied during shift and transfer of the dyestuff from the image transferable sheet to the image-reception layer 302 can be reduced to a minimum possible, the effective thermal efficiency thereby being correspondingly improved and ample image formation being accelerated. If necessary, however, these cushioning layer and heat-insulating layer can be prepared independently and arranged concurrently in any arranging order.

Additionally, when the intermediate layer 304 is arranged at a higher level than the parting agent layer 303', the intermediate layer 304 will be conjointedly peeled off in the case of peel-off of the image reception layer 302. On the contrary, when the intermediate layer 304 is arranged at a lower level than the parting agent layer 303', the intermediate layer will remain on the sheet-like substrate 301 after execution of the separation of image-reception layer 302. In this case, therefore, the intermediate layer 304 may be made preferably and at least substantially transparent, when the peeled-off image-reception layer 302 is stuck on a decorative product, while directing the surface of parting agent layer 303 towards the latter.

In the modifications shown in FIGS. 16, 17, and 18, modified from the foregoing embodiment shown in FIG. 15, a further protecting layer 305 is provided between the image-reception layer 302 and the sheet-like substrate 301. This protecting layer 305 serves to prevent deterioration of the formed images in the image-reception layer 302 when the latter is stuck on the decorating product while directing the surface (more specifically the image-formed surface) towards the product. For example, this protecting layer 305 is prepared from a superior material which exhibits at least one of desirous properties such as antiwearing, light-fast, weather proofing and anti-chemical qualities. With the use of the protecting layer 305 having these superior qualities, the images can represent improved fastness in the above various aspects, even after execution of the foregoing sticking procedure.

In the modification shown in FIG. 16, the protecting layer 305 is arranged between the intermediate layer 304 and the parting agent layer 303'.

In the further modification shown in FIG. 17, the protecting layer 305 is arranged between the image-reception layer 302 and the parting agent layer 303'.

In still another modification shown in FIG. 18, the intermediate layer 304 takes the role of the protecting layer 305.

In each of these modifications, the protecting layer 305 is arranged in neighboring relationship with the partition agent layer 303', whereby the image-formed and remotely arranged, image-reception layer 302, kept in its up-and-down reversed state, is capable of adhering securely to the decorative product, so as to be positioned as an uppermost layer, as may be required. In a still further modification shown in FIG. 19, derived from that shown in FIG. 14, a sticking layer 306 is further provided between the image-reception layer 302 and the partition agent layer 303. It should be noted, however, that such a sticking layer as at 306 may be provided in any one of other foregoing examples and modifications, if necessary, in neighboring relationship with the parting agent layer 303'.

The provision of such a sticking layer as at 306 is highly valuable when the image-formed and peeled off image-reception layer is adhering without position reversal onto the decorative product. With this arrangement mode, the protecting layer 305 shown in FIGS. 16, 17, and 18 may be dispensed with. If, however, the protecting layer 305 is composed of a material in the form of a sheet-like substrate, the part to be peeled off is thereby strengthened, the peel-off procedure thus being greatly facilitated.

By previous provision of the sticking layer 306, the image-formed and peeled-off, image-reception sheet 302 can be caused to adhere as it is onto the decorative product without use of a separate sticking agent. As the sticking layer 306, an ordinary sticking agent which is active at room temperature can be used. Or alternatively, a heat-sensible or light-sensitive sticking agent may be used, if necessary.

In the foregoing, the main structure of the image transferable sheet employed in the present invention has been described in detail. However, other structural modes than those set forth hereinbefore which occur easily to those skilled in the art may be employable in the invention, and thus they may be included within the scope of the invention without departing from the appended claims.

It should be further noted that, in the present invention, the sheet-like substrate may be provided on its one surface with an image transferable layer capable of peeling off through the intermediary of only one weakly sticking layer.

FIG. 22 shows only schematically in a sectional view a preferred embodiment of such an image-transferable sheet, denoted with same reference numeral 310.

As shown in FIG. 22, the image-transferable sheet 310 represents a basic structural characteristic such that any suitable sheet-like substrate 301 is provided on one of the surfaces with an image-reception layer 302 through an only weakly sticking intermediate layer 402, the layer 302 thus being easily peeled-off when desired. By providing the image-transferable sheet with such a structural characteristic as set forth above, desired positive or negative images are formed by transferring thermally shiftable and transferable dyestuff from the image heat transferable sheet to the image-reception layer 302, and the thus image-formed layer is peeled off from the sheet-like substrate 301 and then attached onto any suitably selected product with the use of proper means or attached per se thereon without the peeling-off operation, the substrate then being peeled off, whereby an image-formed final product can be obtained.

In the foregoing example, it should be noted that the image reception sheet 302 per se has only a thin thickness and thus represents only poor feedability during the sheet-feeding period within the printer at the time of image formation, insufficient cushioning effect and only insufficient thermal efficiency during the printing operation, and further, it is very difficult to treat in advance of as well as after execution of the image formation. Therefore, the coexistence of the image-reception layer 302 and the sheet-like substrate 301 is absolutely necessary. In addition, it is a requisite requirement that the image reception layer 302 be easily peeled off from the sheet-like substrate 301 upon execution of the image forming operation, and thus, the layer 302 and the sheet 301 should not be stuck too strongly together. In order to satisfy this requirement, provision is made of weakly stuck layer 402 therebetween. Thus, it should be noted that the term "weakly stuck" employed in this specification and appended claims may be defined as "to be separable by finger's end and the like means from each other without entailing destruction or breakage of the parts originally stuck together". It is worthwhile to say, in considering the relative relationship between the image-reception layer 302 and the sheet-like substrate 301, there is no necessity to provide the weakly-stuck layer 402 if the aforementioned peeling off is very easy to bring about.

FIG. 23 illustrates still another modification of the image-transferable sheet 310 denoted by the same reference numeral 310 only for simplicity and convenience, wherein a further parting agent layer 303 is provided on the surface of image-reception layer 302.

This layer 302 is provided for occasional thermal sticking between the thermal image transferable sheet, not shown, and the image reception layer 302 in the progress of thermal shift and transfer of the dyestuff from the sheet to the layer 302. This provision of the parting agent layer 303 may be dispensed with if there is no risk of occurrence of such disadvantageous sticking attachment or the sheet under consideration has already been fitted with such a parting agent layer.

A modification shown in FIG. 24 from that shown in FIG. 23 has such a modified structure that a protecting layer 305 is prov