JP2017056658A - Image transfer method and image transfer device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image transfer method and an image transfer device by which variation in a rolled shape due to a difference of an abrupt printing pressure generated in a transfer medium end is suppressed, and defect occurrence due to this can be reduced.SOLUTION: By reducing a pressing pressure of a platen roller onto a transferred medium in a region in which the platen roller 30 and an end of the transferred medium 20 contact each other, generation of a thermal wrinkle on a transfer medium is reduced. As a technique for reducing a pressing pressure of the platen roller, a slit 35 is provided on the platen roller in a region thereof contacting the end of the transferred medium thereby lowering a substantial hardness or a raw material is changed thereby lowering a hardness.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image transfer method and an image transfer apparatus that can reduce problems such as generation of wrinkles in a transfer medium.

  The image forming technique based on the transfer method is a technique for forming an image on a transfer medium by applying heat pressure to the transfer medium and transferring a colored layer or the like on the transfer medium to the transfer medium.

  As a transfer medium, a sublimation dye that has a sublimation dye in the medium and forms an image by transferring the dye to the transfer medium by applying heat pressure, or a meltable ink containing a pigment or the like is used as the medium. There are various types such as a melt-type transfer medium that forms an image by transferring an ink layer having a pigment or the like to the transfer medium by applying heat pressure.

  The prior art will be described below with reference to the drawings.

  FIG. 2 shows a configuration example of a sublimation type transfer medium as a configuration example of the transfer medium. The transfer medium 10 includes a base material 11 made of PET or the like, a backcoat layer 12 formed on one surface of the base material 11, and ink layers 13, 14 and 15 formed on the other surface of the backcoat layer 12. It consists of. Since the back coat layer 12 is a portion in direct contact with the thermal head 40, heat resistance and slipperiness are required. The ink layers 13 to 15 contain a sublimable dye. When energy is applied to the ink layers 13 to 15, the sublimable dye is transferred. In FIG. 2, the ink layer 13 contains a yellow dye, the ink layer 14 contains a magenta dye, and the ink layer 15 contains a cyan dye.

  Next, a procedure for forming an image using the transfer medium 10 and the image transfer apparatus 100 will be described with reference to FIG.

  When an image (original image) to be printed is input to a control device 70 constituted by a personal computer (PC) or the like, the control device 70 faithfully reproduces the original image in consideration of the printing sensitivity and the printing environment of the transfer medium 10 and the transferred medium 20. Data for forming an image for reproduction is created.

  In the image transfer apparatus 100, the transfer medium 10 is supplied from a supply roll 61 that supplies the transfer medium 10 to a transfer unit including the thermal head 40, the platen roller 30, and the peeling plate 50, and at the same time, the transfer medium 20 is also supplied to the transfer unit. Is done. In the transfer unit, the transfer medium 10 is disposed on the thermal head 40 side, and the transfer medium 20 is disposed on the platen roller 30 side.

  The thermal head 40 is arranged on the back coat layer 12 side of the transfer medium 10, and the transfer medium 20 is arranged on the ink layers 13 to 15 side. A platen roller 30 is disposed on the surface of the transfer medium 20 opposite to the surface facing the transfer medium 10, and both the transfer medium 10 and the transfer medium 20 are fixed to each other with the thermal head 40 and the platen roller 30. It is designed to be sandwiched by pressure.

  The thermal head 40 includes a large number of minute heating elements, and these minute heating elements are arranged in a line in a direction orthogonal to the transfer direction of the transfer medium 10, that is, in the width direction of the transfer medium 10. The size of the minute heating element is approximately several μ to several 100 μ.

  Each of the minute heating elements has a structure capable of individually flowing current, and can be individually heated by flowing current individually. Usually, there are many usages in which heating is performed only for a short time by supplying a pulse-like current for a very short time.

  In a state where the transfer medium 10 and the transfer target medium 20 are sandwiched between the thermal head 40 and the platen roller 30, an electric current is instantaneously passed through the minute heating element of the thermal head 40 to raise the minute heating element to a high temperature. The sublimable dye on the transfer medium 10 is transferred to the transfer medium 20. According to the image forming data created by the control device 70, the minute heating elements are individually heated to transfer the dye in the transfer medium 10 to the transfer medium 20, thereby forming a desired image.

  After passing through the thermal head 40, the transfer medium 10 and the transfer target 20 are separated by the peeling plate 50, and the transfer medium 10 is taken up by a take-up roll 62.

  In the case of expressing a color image, as shown in FIG. 3, a transfer medium 10 having panels 13, 14 and 15 each composed of ink layers for transferring yellow, magenta, and cyan is used. As an example of color image formation, first, according to the image data for yellow, the yellow dye in the yellow panel 13 is transferred to the transfer target 20 to form a yellow image, and between the thermal head 40 and the platen roller 30. After separation until the distance reaches the set value, the transfer medium 20 is returned to a predetermined transfer start position, and the magenta panel 14 is set to the transfer start position. Thereafter, the transfer medium 10 and the transfer medium 20 are sandwiched again by the thermal head 40 and the platen roller 30, and the magenta dye in the magenta panel 14 is transferred according to the magenta image. As for cyan, a color image is formed by transferring in the same manner.

  Further, the transfer medium 10 may be provided with a black ink panel as necessary.

  The supply roll 61 and the take-up roll 62 are provided with a drive device with a control function in which a torque value is set so that the tension of the medium being transferred and the strength of the take-up are constant. is there. Depending on the transfer device, a drive device capable of variable torque control may be used.

  As described above, heat is used for transfer, and the amount of expansion of the transfer medium 10 is changed by the applied heat. That is, when an image is transferred, there are a portion where the amount of ink transferred is large and a portion where the amount of ink is small, so that a portion where the expansion is large and a portion where the expansion is small occur two-dimensionally. When the extension is large, slack occurs, and the tension is weaker than that of the small extension, so that the in-plane tension of the transfer medium 10 is not uniform.

  It is the ribbon end that has the largest expansion difference of the transfer medium 10. A cross section of the image transfer apparatus is shown in FIG. As described above, the sublimation dye in the transfer medium is transferred to the transfer medium 20 by the heat generated from the minute heating element provided in the thermal head while applying the predetermined pressure to the transfer medium 10 and the transfer target 20 by the thermal head 40 and the platen roller 30. However, since the width of the transfer medium 10 and the width of the transfer medium 20 are usually narrower than the transfer medium 20, an area where the transfer medium end is not in contact with the transfer medium is generated. In other words, there will be places where sufficient printing pressure is applied or not.

  Accordingly, even if the heat generation state of the thermal head 40 is the same, a situation occurs in which the method of applying the heat pressure changes greatly, and thus a large difference occurs in the elongation amount at this portion. In this way, wrinkles may occur along a boundary at which a large difference in elongation occurs.

In this situation, when the transferred transfer medium 10 is taken up by the take-up roll 62 as shown in FIG. 4, the boundary between the place where the heat at the end of the transfer medium is applied and the place where the heat is not applied is the stretch amount. Changes rapidly, and wrinkles are present, so that it is very difficult to make the winding shape uniform. Therefore, the winding diameter also changes greatly, and the transfer medium tension changes accordingly.
Until now, various inventions for suppressing fluctuations in the tension of the transfer medium have been made from the viewpoint of relating to defects such as transfer medium tension and wrinkles (for example, Patent Documents 1 and 2). Japanese Patent Application Laid-Open No. H10-228667 proposes a solution method in which a difference occurs in the frictional force between the thermal head and the transfer medium due to a difference in thermal energy applied to the thermal head, and density unevenness occurs due to this frictional difference.

  Patent Document 2 proposes to make the winding shape uniform by changing the winding force according to the thermal pressure condition of the thermal head.

JP 2011-212998 A Japanese Patent Laid-Open No. 11-321054

  However, the inventions so far aimed at suppressing fluctuations in tension due to the expansion of the transfer medium due to the difference in thermal energy applied under a certain printing pressure. It is not compatible with.

  The present invention provides an image transfer method and an image transfer apparatus that can suppress fluctuations in the winding shape caused by a sudden difference in printing pressure generated at the end of a transfer medium, and reduce the occurrence of problems caused by this. The purpose is to do.

  The present invention has been made to solve these problems.

  That is, according to the first aspect of the present invention, there is provided a transfer medium including a transfer body on one surface and a transfer medium having an image receiving layer for receiving the transfer body on at least one surface. In an image transfer method in which an image is formed by overlapping the image-receiving layer surface of a transfer body with a thermal head and a platen roller, and further applying heat pressure to transfer the transfer body on the transfer medium to the image-receiving layer of the transfer medium. The image transfer method is characterized in that the outer side of the platen roller including the end of the transfer medium has a lower pressing pressure than the center.

Next, according to a second aspect of the present invention, there is provided a transfer medium including a transfer body on one surface, and a transfer medium having an image receiving layer for receiving the transfer body on at least one surface. A mechanism for superimposing the image-receiving layer surface of the transfer object and conveying it along the conveying direction;
A thermal head that heats the transfer medium and transfers a transfer body in the transfer medium to the transfer medium;
A platen roller disposed to face the thermal head;
An image transfer apparatus comprising a mechanism for applying a printing pressure by sandwiching the transfer medium and the transfer medium between the thermal head and the platen roller,
The image transfer apparatus is characterized in that a pressing pressure of the outer platen roller including a region in contact with an end of the transfer medium is lower than that of a central portion of the platen roller.

  According to one aspect of the present invention, the hardness of the platen roller in the region including the paper edge is reduced in order to reduce the abrupt change in thermal pressure where the ribbon edge is in contact with the image receiving paper. The present invention provides an image transfer method characterized by suppressing a rapid change in heat pressure at the paper edge.

  As a result, the fluctuation in tension at the end of the ribbon can be reduced, and image formation by stable transfer can be performed.

It is a figure which shows an example of the platen roller to which this invention is applied. It is a layer composition sectional view showing an example of a transfer medium. FIG. 6 is a layout diagram of each color panel of a transfer medium. It is a schematic block diagram which shows an example of the conventional image transfer apparatus. It is a schematic block diagram which shows the cross section of the place relevant to transcription | transfer in an image transfer apparatus.

  In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the present invention. It will be apparent, however, that one or more embodiments may be practiced without such specific details.

  Embodiments of the present invention will be described below.

  The platen roller usually has a structure in which a resin or rubber is wound around an iron core. Resin and rubber are molded to an appropriate diameter according to the design of the printer, and then the surface is polished to increase the flatness. This prevents the occurrence of contact between the thermal heads when transferring. The surface hardness of the platen is mostly around 50-65 in Shore hardness A.

  The thickness of the transfer medium is about 200 μm. The printing pressure may be about 6 kgf / cm 2. Under such conditions, the image receiving paper does not dig into the platen, so that the edge of the medium to be transferred becomes a step and a sudden printing pressure difference occurs. For this reason, the extension amount changes abruptly along the edge of the transfer medium, and wrinkles may occur due to this. Since these wrinkles are physical irregularities that occur almost continuously in the flow direction of the transfer medium, when the transfer medium 20 is wound up, the portions including many wrinkles become thicker.

  In order to reduce this wrinkle, as shown in FIG. 1, the contact between the platen roller 30 and the transfer medium 20 is reduced by lowering the pressing force when the platen roller 30 is in contact with the end of the transfer medium 20. Alleviates sudden printing pressure difference at the edge. As a method for lowering the pressing pressure, there is a method in which a material having a low hardness is used for a part of the platen roller 30 and a method in which the hardness, that is, the pressing pressure is substantially reduced by inserting a slit 35 in the platen roller 30.

  If the printing pressure difference generated at the end of the transfer medium can be reduced, wrinkles generated along the printing pressure difference can be reduced, and a stable winding shape can be realized. The tension can be made uniform, and problems caused by the non-uniformity of the winding tension can be improved.

  Although the present invention has been described above with reference to specific embodiments, the present invention is not limited to these descriptions. From the description of the invention, other embodiments of the invention will be apparent to persons skilled in the art, along with various variations of the disclosed embodiments. Therefore, it is to be understood that the claims encompass these modifications and embodiments that fall within the scope and spirit of the present invention.

The effect of preventing wrinkle generation by the image transfer method according to the embodiment of the present invention was verified. For the verification, a sublimation printer that uses a sublimation transfer medium having a width of 160 mm as the transfer medium 10 and performs printing is used. As shown in FIG. 2, the sublimation type transfer medium 10 has ink layers 13 to 15 formed on the other surface of the PET base material 11 on which the backcoat layer 12 is formed.

  The material composition and composition ratio of the backcoat layer 12 and the ink layers 13 to 15 of the transfer medium used in this verification are shown below. The ink layer is composed of three types of yellow, magenta, and cyan. Here, a material configuration example of the cyan layer is shown. In addition, when described as “parts” in the following description, unless otherwise specified, the weight standard is indicated. The present invention is not limited to the following examples.

(Back coat layer)
Acrylic polyol resin 50 parts Polyoxyalkylene alkyl ether / phosphate ester 10 parts Talc 24 parts 2,6-tolylene diisocyanate prepolymer 16 parts

(Cyan ink layer)
C. I. Solvent Blue 63 60 parts Polyvinyl acetal resin 40 parts

  The platen roller used was a polyurethane-based material having a surface hardness of 63 with a Shore hardness A.

  First, printing was performed using a normal platen roller. In this case, it was confirmed that the transfer medium was wrinkled along the transfer medium edge. Next, slits 35 having a depth of about 0.5 mm are inserted at intervals of about 1.5 to 2.0 mm in the range of about 10 mm width around the vicinity of the transfer medium end of the platen roller to substantially reduce the hardness. When the image was transferred using a platen roller, it was confirmed that wrinkles along the edge of the image receiving paper were improved.

  In this verification, verification was performed by a method of inserting a slit to lower the hardness, and a certain effect was confirmed. Therefore, according to the embodiment of the present invention, the image transfer method is effective for reducing wrinkle generation. Was verified.

  In addition, although the method of providing the slit part 35 was mentioned as an example of the hardness adjustment of a platen roller in embodiment of this description, it shall not be limited to this method.

  In the examples, sublimation transfer media were used to verify the effect, but the transfer media are not limited.

DESCRIPTION OF SYMBOLS 10 ... Sublimation type transfer medium 11 ... Base material 12 ... Backcoat layer 13 ... Yellow ink layer 14 ... Magenta ink layer 15 ... Cyan ink layer 20 ... Transfer medium 30 ... Platen roller 35 ... Slit part 40 ... Thermal head 50 ... Stripping Plate 61 ... Supply roll 62 ... Winding roll 70 ... Control device 100 ... Image transfer device

Claims (2)

  A transfer medium including a transfer body on one surface and a transfer medium having an image receiving layer for receiving the transfer body on at least one surface overlap the surface including the transfer body of the transfer medium and the image receiving layer surface of the transfer body. In an image transfer method for forming an image by sandwiching between a thermal head and a platen roller and further transferring a transfer body on a transfer medium to an image receiving layer of the transfer medium by applying heat pressure, the platen roller including the transfer medium end An image transfer method, wherein the outer side has a lower pressing pressure than the center. A transfer medium including a transfer body on one surface and a transfer medium having an image receiving layer for receiving the transfer body on at least one surface overlap the surface including the transfer body of the transfer medium and the image receiving layer surface of the transfer body. A mechanism for transporting along the transport direction;
A thermal head that heats the transfer medium and transfers a transfer body in the transfer medium to the transfer medium;
A platen roller disposed to face the thermal head;
An image transfer apparatus comprising a mechanism for applying a printing pressure by sandwiching the transfer medium and the transfer medium between the thermal head and the platen roller,
An image transfer apparatus, wherein a pressing force of the outer platen roller including a region in contact with an end of the transfer medium against the transfer medium is lower than a central part of the platen roller.

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