JP2019171609A - Thermal transfer printing device and thermal transfer printing method - Google Patents

Abstract

To suppress curling amount of printed matter.SOLUTION: A thermal transfer printing device includes: a supply section 3 which supplies a thermal transfer sheet 5; an image receiving sheet roll 6 which winds and unwinds the image receiving sheet 7; a printing section 10 which holds the thermal transfer sheet 5 and the image receiving sheet 7 between a thermal head 1 and a platen roll 2, performs thermal transfer of color materials on the image receiving sheet 7 from the thermal transfer sheet 5, and prints an image; and a recovery section 4 which recovers the thermal transfer sheet 5 after the thermal transfer. The thermal transfer sheet 5 and the image receiving sheet 7 are held between the thermal head 1 and the platen roll 2 at a position where the thermal head 1 is pushed into the platen roll 2 side more than during image printing processing, and decurling processing for conveying the image receiving sheet 7 is performed while the image receiving sheet 7 is heated by the thermal head 1.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a thermal transfer printing apparatus and a thermal transfer printing method.

  A thermal transfer printing apparatus is known in which a thermal transfer sheet and an image receiving sheet are sandwiched between a thermal head and a platen roll, heat is applied from the thermal head to the thermal transfer sheet, and ink of the thermal transfer sheet is transferred to the image receiving sheet.

  The image receiving sheet is loaded in the thermal transfer printing apparatus in a roll shape wound around the core (or without the core). For this reason, there has been a problem that curled curl (warpage) occurs in the printed matter produced by the thermal transfer printing apparatus.

JP 2011-5700 A JP-A-2015-147336

  The present invention has been made in view of the above-described conventional situation, and an object of the present invention is to provide a thermal transfer printing apparatus and a thermal transfer printing method that suppress a curl amount of a printed matter.

  The thermal transfer printing apparatus of the present invention includes a supply unit for supplying a thermal transfer sheet, an image receiving sheet roll for feeding and winding the image receiving sheet, and sandwiching the thermal transfer sheet and the image receiving sheet between a thermal head and a platen roll, A printing unit that prints an image by thermally transferring ink from the thermal transfer sheet to the image receiving sheet; and a collection unit that collects the thermal transfer sheet after the thermal transfer. The thermal transfer sheet and the image receiving sheet are sandwiched between the thermal head and the platen roll at a position pushed inward, and a decurling process is performed in which the image receiving sheet is conveyed while the image receiving sheet is heated by the thermal head. is there.

  In one aspect of the present invention, the thermal transfer sheet is provided with a color material layer and a protective layer, and the thermal head heats the image receiving sheet through a used protective layer forming region during the decurling process.

  In one aspect of the present invention, the area where the thermal head used in the decurling process heats the used protective layer forming area is protected by the thermal head when the protective layer is transferred onto the image printed on the image receiving sheet. The layer formation region is smaller than the region to be heated.

  In the thermal transfer printing method of the present invention, an image receiving sheet fed from a thermal transfer sheet and an image receiving sheet roll is sandwiched between a thermal head and a platen roll, and a color material is thermally transferred from the thermal transfer sheet to the image receiving sheet to print an image. A thermal transfer printing method, wherein the thermal transfer sheet and the image receiving sheet are sandwiched between the thermal head and the platen roll at a position where the thermal head is pushed to the platen roll side than during image printing processing, and the thermal head The decurling process for conveying the image receiving sheet while heating the image receiving sheet is performed.

  According to the present invention, the curl amount of a printed product can be suppressed.

1 is a schematic configuration diagram of a thermal transfer printing apparatus according to an embodiment of the present invention. It is a top view of a thermal transfer sheet. It is sectional drawing of an image receiving sheet. (A) (b) is a schematic diagram explaining the position of a thermal head. It is a schematic diagram explaining the heating area | region in a protective layer formation area. (A) (b) is a figure which shows the example of the advancing / retreating mechanism of a platen roll. (A)-(c) is a figure which shows the example of the advancing / retreating mechanism of a thermal head.

  FIG. 1 is a schematic configuration diagram of a thermal transfer printing apparatus according to an embodiment of the present invention, FIG. 2 is a plan view of a thermal transfer sheet used in the thermal transfer printing apparatus, and FIG. 3 is a sectional view of an image receiving sheet.

  In the thermal transfer printing apparatus, a Y layer 51 containing a yellow dye (Y), an M layer 52 containing a magenta dye (M), a C layer 53 containing a cyan dye (C), and a protective (OP) layer 54 are provided in a surface sequential manner. Using the thermal transfer sheet 5 thus provided, a thermal head 1 is provided which prints an image by sublimation transfer of Y, M and C onto an image receiving sheet 7 and transfers a protective layer onto the image. The image to be printed is, for example, a human image such as a face image, or characters such as an address or name.

  A supply unit 3 formed by winding the thermal transfer sheet 5 is provided on the downstream side of the thermal head 1, and a recovery unit 4 is provided on the upstream side of the thermal head 1. The thermal transfer sheet 5 fed out from the supply unit 3 passes through the thermal head 1 and is wound up and collected by the collection unit 4.

  A rotatable platen roll 2 is provided on the side opposite to the thermal head 1 with the thermal transfer sheet 5 interposed therebetween. The printing unit 10 including the thermal head 1 and the platen roll 2 sandwiches the image receiving sheet 7 and the thermal transfer sheet 5 and heats the thermal transfer sheet 5 to thermally transfer the dye onto the image receiving sheet 7 to form an image.

  In the thermal transfer sheet 5, a Y layer 51, an M layer 52, a C layer 53, and an OP layer 54 are sequentially formed on one surface of the base material layer from the collection unit 4 side. For the Y layer 51, the M layer 52, and the C layer 53, it is preferable to use a material obtained by melting or dispersing a sublimable dye in a binder resin. The OP layer 54 is preferably made of a transparent material having adhesiveness, light resistance, and the like.

  As the base material layer of the thermal transfer sheet 5, a conventionally known material having a certain degree of heat resistance and strength can be used. For example, a polyethylene terephthalate (PET) film, a polyethylene naphthalate film, a polystyrene film, a polypropylene (PP) film, a polycarbonate film, etc. are mentioned.

  A back layer is provided on the other surface of the base material layer, that is, the surface opposite to the surface coated with the dye. The thermal head 1 heats the thermal transfer sheet 5 from the back layer side. The back layer has a function of improving heat resistance so that the thermal transfer sheet 5 is not deformed by heat at the time of thermal transfer, and also improving the running performance of the thermal head 1 at the time of thermal transfer to suppress sticking and the like. The back layer can be generally formed by applying and drying a binder resin to which a lubricant, a surfactant, inorganic particles, organic particles, a pigment, and the like are added.

  The thermal transfer sheet 5 is provided with a melt layer containing a pigment and a color material such as carbon black together with a binder resin in order of the Y layer 51, the M layer 52, and the C layer 53 which are dye layers for sublimation transfer. Also good.

  On the upstream side of the thermal head 1, there are provided a capstan roller 9 a that can be rotated and driven for conveying the image receiving sheet 7, and a pinch roller 9 b for pressing the image receiving sheet 7 against the capstan roller 9 a.

  The image receiving sheet 7 is fed out from an image receiving sheet roll 6 around which the image receiving sheet 7 is wound. The image receiving sheet roll 6 is attached to a winding shaft component (not shown). When the winding shaft component is rotated (forward / reverse rotation), the image receiving sheet roll 6 rotates and the image receiving sheet 7 is fed out (conveyed downstream). And winding (transport to the upstream side) is performed.

As the image receiving sheet 7, a known one used in this type of thermal transfer printing apparatus can be used. For example, as shown in FIG. , And a receiving layer 75 laminated in this order can be used. As the void-containing film 74, various films can be used as long as voids are formed in the film. For example, it is possible to use a film in which a void is formed in a film by adding a void developing agent in PET, forming a film, and stretching. As the base material, polyolefin such as PP and PE (polyethylene) can be used in addition to PET.

  The control device 14 controls driving of each part of the thermal transfer printing apparatus, and performs printing processing and decurling processing described later. In the printing process, first, the image receiving sheet 7 and the Y layer 51 are aligned, and the thermal head 1 contacts the platen roll 2 through the image receiving sheet 7 and the thermal transfer sheet 5. Next, the capstan roller 9a and the collection unit 4 are driven to rotate, and the image receiving sheet 7 and the thermal transfer sheet 5 are sent upstream. During this time, the area of the Y layer 51 is selectively and sequentially heated by the thermal head 1 based on the image data, and Y is sublimated and transferred from the thermal transfer sheet 5 onto the image receiving sheet 7.

  After the sublimation transfer of Y, the thermal head 1 rises and leaves the platen roll 2. Next, the image receiving sheet 7 and the M layer 52 are aligned. M and C are sequentially sublimated and transferred onto the image receiving sheet 7 in the same manner as the Y sublimation transfer method, and an image for one screen is formed on the image receiving sheet 7. Next, the OP layer 54 is transferred onto the image by the thermal head 1.

  Thereafter, the image receiving sheet 7 to which the protective layer has been transferred is cut at the rear edge of the screen by a cutter (not shown) provided on the downstream side to produce a printed matter on which an image is formed.

  As described above, the image receiving sheet 7 is loaded in the thermal transfer printing apparatus while being wound in a roll shape. For this reason, curled curls (warps) may occur in the printed matter. Therefore, in this embodiment, decurling processing for reducing curling of the image receiving sheet 7 is performed before the printing processing.

  In the decurling process, the image receiving sheet 7 is wound up while applying thermal energy by the thermal head 1 in a state where the thermal head 1 is pushed further toward the platen roll 2 than the position at the time of the printing process. FIG. 4A shows an example of the position (first head position) of the thermal head 1 during the printing process, and FIG. 4B shows an example of the position (second head position) of the thermal head 1 during the decurling process. Show. The platen roll 2 has a structure that follows the position of the thermal head 1.

  By pushing the thermal head 1 toward the platen roll 2, a bent path (bent conveyance path) of the image receiving sheet 7 is formed. By passing the bending path while heating the image receiving sheet 7, curling of the image receiving sheet 7 is suppressed. The amount of energy applied by the thermal head 1 to the image receiving sheet 7 during the decurling process is 255/255 when the maximum density is printed when the Y layer 51, the M layer 52, and the C layer 53 are thermally transferred. It is preferably about 140/255 or more and 180/255 or less.

  During the decurling process, a used protective layer forming region in which the protective layer is transferred onto the image one screen before is disposed between the thermal head 1 and the image receiving sheet 7. In other words, during the decurling process, thermal energy is applied to the image receiving sheet 7 from the thermal head 1 through the used protective layer forming region one screen before. For example, in the used protective layer forming region, the surface of the base material layer is exposed at a portion where the protective layer is transferred.

  As shown in FIG. 5, it is preferable that the region R2 for heating the used protective layer forming region during the decurling process is slightly smaller than the region R1 for heating when the protective layer is transferred onto the image in the printing process. For example, the region R2 is smaller than the region R1 by about 5 mm in circumference. Thereby, it is possible to prevent the protective layer from being transferred from the thermal transfer sheet 5 to the image receiving sheet 7 before dye transfer during the decurling process.

  Immediately before the leading edge of the image receiving sheet 7 reaches the thermal head 1, the winding of the image receiving sheet 7 and the heating by the thermal head 1 are stopped, and the decurling process is finished. Thereafter, the printing process is performed with the position of the thermal head 1 set to the first head position shown in FIG.

  By performing the decurling process before the printing process, the curl amount of the printed matter to be produced can be suppressed.

  One possible decurling method is to pass the image-receiving sheet that has been subjected to image formation and transfer of the protective layer through a bending path on the downstream side of the thermal head. However, in such a method, it is necessary to loosen the bending path so that the surface of the protective layer is not damaged, and curling cannot be effectively reduced.

  On the other hand, in this embodiment, since the decurling process is performed before the printing process, the image receiving sheet 7 can be passed through a path having a large bending angle and can be heated, so that curling can be effectively reduced.

  In the above embodiment, the example using the thermal transfer sheet in which the dye layer and the protective layer are provided in the same base layer in the surface order has been described. However, the sheet provided with the dye layer and the sheet provided with the protective layer And may be separated. In this case, the thermal head and the platen roll for transferring the protective layer may be configured as in the above embodiment.

  In the above embodiment, an example in which heating is performed while winding the image receiving sheet 7 during the decurling process has been described. However, heating may be performed while the image receiving sheet 7 is fed out.

  6A and 6B show an example of a mechanism for moving the platen roll 2 back and forth. A rotating shaft 21 of the platen roll 2 is supported by a bearing 22. The bearing 22 is supported by one end of a lever 23 that can rotate about a shaft 23a.

  The other end portion of the lever 23 is supported by being urged in the direction of arrow A by a spring (not shown) and crimped to the cam 24. When the cam 24 rotates, the lever 23 rotates and the platen The position of the roll 2 can be changed. For example, the position of the platen roll 2 can be switched between a position at the time of printing processing (and standby) shown in FIG. 6A and a position at the time of decurling processing shown in FIG.

  FIGS. 7A to 7C show examples of the advance / retreat mechanism of the thermal head 1. One end of a coil spring 11 is attached to the thermal head 1, and a cam 12 is provided on the other end of the coil spring 11. As the cam 12 rotates, the coil spring 11 contracts and the thermal head 1 is biased toward the platen roll 2 side.

  FIG. 7A shows the position of the thermal head 1 during standby. FIG. 7B shows the position of the thermal head 1 during the printing process. FIG. 7C shows the position of the thermal head 1 during the decurling process.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

DESCRIPTION OF SYMBOLS 1 Thermal head 2 Platen roll 3 Supply part 4 Collection | recovery part 5 Thermal transfer sheet 6 Image receiving sheet roll 7 Image receiving sheet 10 Printing part 14 Control apparatus

Claims (4)

A supply unit for supplying a thermal transfer sheet;
An image receiving sheet roll for feeding and winding the image receiving sheet;
A printing section for sandwiching the thermal transfer sheet and the image receiving sheet between a thermal head and a platen roll, and thermally transferring ink from the thermal transfer sheet to the image receiving sheet to print an image;
A collection unit for collecting the thermal transfer sheet after thermal transfer;
With
The thermal transfer sheet and the image receiving sheet are sandwiched between the thermal head and the platen roll at a position where the thermal head is pushed to the platen roll side than during image printing, and the image receiving sheet is heated by the thermal head. A thermal transfer printing apparatus that performs a decurling process for conveying the image receiving sheet. The thermal transfer sheet is provided with a color material layer and a protective layer,
2. The thermal transfer printing apparatus according to claim 1, wherein, during the decurling process, the thermal head heats the image receiving sheet through a used protective layer forming region.   The area where the thermal head used in the decurling process heats the used protective layer forming area is an area where the thermal head heats the protective layer forming area when the protective layer is transferred onto the image printed on the image receiving sheet. The thermal transfer printing apparatus according to claim 2, wherein the thermal transfer printing apparatus is smaller. A thermal transfer printing method in which an image receiving sheet fed from a thermal transfer sheet and an image receiving sheet roll is sandwiched between a thermal head and a platen roll, and a color material is thermally transferred from the thermal transfer sheet to the image receiving sheet to print an image,
The thermal transfer sheet and the image receiving sheet are sandwiched between the thermal head and the platen roll at a position where the thermal head is pushed to the platen roll side than during image printing, and the image receiving sheet is heated by the thermal head. A thermal transfer printing method, wherein a decurling process for conveying the image receiving sheet is performed.

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