JPS6253887A - Thermal transfer copying method - Google Patents

Abstract

PURPOSE:To enable a double-side original, a book or the like to be easily copied, by providing a step of obtaining an ink image on an intermediate transfer body as a mirror image of an original, and a step of laying a transfer body on the ink image side of the intermediate transfer body and heating to transfer the ink image onto the transfer body. CONSTITUTION:Rays alpha from a light source 11 are transmitted through the intermediate transfer body to reach an original 16. At a ground part of the original, a part of the rays is scattered as indicated at delta', while other part is transmitted as indicated at delta, so that neither of the parts of the rays generates heat. On the other hand, at an image part 16a, the rays alpha are absorbed to generate heat. The heat beta thus generated is transmitted to an ink layer 14 to melt the ink at the part facing the image part 16a. The melted ink 17 forms a mirror image of the image part 16a. The intermediate transfer body 12 with the ink image 12a (mirror image) formed thereon is released from an ink sheet 15, and is passed between a heated roller 19 and a pressing roller 20 together with a sheet 18 laid thereon, whereby the ink is thermally melted and is transferred onto the transfer body 18, thereby obtaining a copy image corresponding to the image of the original.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a thermal transfer copying method using a heat-melting ink sheet.

(Prior Art 1) Conventionally, there is a method shown in FIGS. 9 and 10 as a method of copying an original image by a thermal transfer method.

In this method, as shown in FIG. 9, an original 1 and a transfer paper 5 as a transfer medium are brought into close contact with each other with an ink sheet 4 in between, and as shown in FIG. etc. are exposed. When the light beam from the light source 6 is absorbed by the image area 3 (FIG. 9) of the original 1, the binding area generates heat, and this heat causes the ink on the ink sheet 4 in the corresponding area to melt and transfer onto the transfer paper 5. transcribed.

In this conventional method, the light and heat from the light source 6 must pass through the original 1, so it is not possible to copy originals with images printed on both the front and back sides (double-sided originals), books, etc. There is a drawback. Further, in the case of a thick original, the heat generated in the image area 3 is easily diffused, and as a result, there is a drawback that a clear copy image cannot be obtained.

(Purpose) The present invention has been made in order to eliminate the drawbacks of the conventional thermal transfer copying method described above. It is an object of the present invention to provide a copying method using a thermal transfer method capable of obtaining a copied image.

(Structure) The above object is achieved by the present invention having the following structure. That is, in the present invention, the image surface of an original is superimposed on the ink support side of an ink sheet having an ink layer formed on the support, and an intermediate transfer member is further superimposed on the ink layer side of the ink sheet. Then, the intermediate transfer members are brought into close contact with each other, and then exposed to light from the intermediate transfer member side to generate heat in the image area of the document, and this heat is transferred to the ink sheet to selectively melt the ink and transfer it to the intermediate transfer member. The first step is to create a mirror image corresponding to the original image on the intermediate transfer body using By doing this, the second step of melting the ink image on the intermediate transfer member and transferring it onto the transfer member obtains a normal image corresponding to the original image on the transfer member.

Hereinafter, the present invention will be explained based on Examples.

FIG. 1 is a diagram for explaining the principle of the copying method according to the present invention, particularly the first step thereof. In the figure, light source 1
1, the intermediate transfer body 12, the ink sheet 15, and the original 16 are stacked on top of each other in this order. In the figure, each member is shown separated from each other for the sake of explanation, but in reality, these members are pressed from above and below in the figure, and a gap like an air pocket is formed between them. Make sure they are in close contact with each other to avoid any problems.

The ink sheet 15 is formed by supporting an ink layer 14 by an ink support 13, and the ink layer 14 is overlapped with the intermediate transfer member 12, while the ink support 13 is overlapped with the original 16. The originals 16 are stacked so that the image portion 16m to be copied is on the ink sheet 15 side.

When the intermediate transfer member 12 and the like are exposed by the light source 11 in this state, the light ray α from the light source 11 passes through the intermediate transfer member 12 and the ink sheet 15 and reaches the original 16 . This light ray α that has reached the original 16 is exposed to the background part (for example, white) of the original 16.
Then, part of the light is scattered like δl, and the other part is transmitted like δ, and neither part generates heat. On the other hand,
In the image area (for example, black) 16a, the light ray α is absorbed and heat generation occurs.

The heat β generated in the image area 16a is transferred to the ink support 1
6 to the ink layer 14, and melts the ink in the portion facing the image area 16a. This melted ink 1
7 is transferred to the intermediate transfer body 12 in close contact to form a mirror image of the image portion 16a. The above is the first step.

Next, the intermediate transfer body 12 on which the ink image 12a, which is a mirror image, is formed is peeled off from the ink sheet 15, and as shown in FIG. A certain sheet 18 (for example, plain paper) is overlapped and further passed between a heating roller 19 having a built-in heater lamp 19a and a pressure roller 20. During this passing process, the ink of the ink image 12a is thermally fused and transferred from the intermediate transfer member 12 to the transfer member 18, and a copy image corresponding to the image of the original is obtained on the transfer member 18. This is the second step.

In the above copying method, the light source 11 is preferably a flash light source such as a xenon lamp capable of short-time exposure in order to prevent unnecessary diffusion of the generated heat.

Since the irradiated light from the light source 11 is used as radiant heat, its long wavelength components are effective.

As for the exposure method, instead of exposing the entire surface of the document 16 at one time, the document surface may be divided into several regions and each region may be exposed sequentially. Further, a curved reflector, a multifaceted reflector, a lens, etc. are arranged around the tubular light source to form an exposure slit in which the light rays from the light source 11 are converged, and by moving this slit, the entire surface of the document can be covered. A pseudo flash exposure method using light scanning may also be used. According to this method, it is possible to successively expose a fixed area to high energy light for short periods of time.

The ink sheet 15 can be a thermal transfer ink sheet that has been used in printers in recent years. This general ink sheet has an ink layer 14 of about 1 to 6 .mu.m thick, which is made by dispersing dye or pigment in heat-melting wax, on an ink support 13 of about 3 to 10 .mu.m of polyester. The lower limit of the softening point of the ink layer 14 is approximately 70 to 90°C.

In addition, since the color tone of the ink and the wavelength of light are closely related to this ink layer 14, dye-type ink, which absorbs less long-wavelength components of light, is generally better than pigment-type ink. preferable. For example, for black ink, a black pigment such as carbon black is undesirable because it has a high absorption rate for long wavelength components, and a mixture mainly consisting of three dye colors, cyan, magenta, and yellow, which absorbs only in the visible range, is used. body etc. is desirable.

As the intermediate transfer member 12, a sheet of polyethylene, terephthalate, polypropylene, polyethylene terephthalate, polyvinyl chloride, polyvinylidene chloride, nylon, or other material is used. In terms of characteristics, it is preferable to use a thin layer with high transmittance for long wavelength light and low thermal diffusion and heat insulation properties. Considering practicality such as operability and cost, 10 to 200μ
Furthermore, the thickness is preferably about 40 to 60 μm. As an extreme example, it is possible to use a glass plate with the same thickness as the original.
The exposure energy required to melt the ink depends on the size of the original 16, the image density, the materials of the original 16 and the ink,
It is greatly influenced by the long wavelength absorption rate of light of the ink sheet 15 and the intermediate transfer body 12, etc. However, general A4
For text manuscripts, 500 to 2000 joules is sufficient.

When exposing the original 16 in FIG. 1, a reflective plate is placed on the back of the original 16 and around the light source 11, so that the light transmitted through the white part of the original 16 and reflected and scattered by the cover is reflected again. The light can be reflected by the plate and reach the image area 16b of the original 16 again. In this way, it is possible to improve energy efficiency.

The temperature of the heating roller 19 is influenced by the paper feeding speed and other conditions, but a temperature of about 80 to 150°C is sufficient. Further, the pressure applied by the pressure roller 20 is sufficient to maintain close contact between the intermediate transfer member 12 and the transfer member 18.

In the first step, from the ink sheet 15 to the intermediate transfer body 1
The amount of ink transferred to 2 depends on the difference in ink adhesion. Ink sheet 1 from intermediate transfer body 12
When peeling off the ink sheet 15, as shown in Figure 6L,
If the ink is peeled off so that it is bent at an acute angle, the image is less likely to deteriorate and a stable ink image can be easily obtained.

When copying an original with an image on only one side (a so-called single-sided original), the light source 11 exposes the original 1 in the first step.
It can also be done from the 6th side.

Further, in the second step, the same effect can be obtained even if the image is transferred from the intermediate transfer member 12 to the transfer member 18 using an iron, a hot plate, or the like.

According to the above embodiment, since light and heat do not pass through the original 16 in the first step, the energy from the light source 11 reaches the image 16a without being affected by unstable factors such as the material and thickness of the original 16. . Furthermore, even if there is an image on the back side of the original 16, it does not affect the copying of the image on the front side of the original 16. Further, only the ink support 13 of the ink sheet 15 is present as a heat transfer layer, and this ink support 13 is a thin layer. Therefore, it is possible to minimize image deterioration due to heat diffusion in the heat transfer layer.

In the second step, since the transfer is performed from the intermediate transfer body 12 in the first step, the form of the original 16 is not restricted;
Also, copies can be obtained anywhere. Intermediate transfer body 1
It is also possible to weld the two together into a laminate, and it is also possible to weld it to a foam or the like.

Since copying is performed via the intermediate transfer member 12, the first to second steps are performed. At the stage of moving on to the process, it is possible to delete unnecessary information (unnecessary parts, dirt, etc.) ◇ Also, it is possible to perform intermediate checks on image content and image quality, and re-edit images without damaging the original. I can do it.

If a transparent sheet is used as the intermediate transfer body 12, alignment becomes easy.

In the above embodiment, the heat roller 19 was used as the heating method for the transfer body 12 in the second step. However, other methods described below may be used instead.

When the heat roller 19 as shown in FIG. 2 is used in the second step, even though there is a clear ink image corresponding to the image of the original 16 on the intermediate transfer member 12 in the first step, the transfer member The ink image transferred onto 18 may become unclear. This is considered to be due to differences in the temperature of the heat roller 19, the pressure between the heat roller 19 and the pressure roller 20, the linear speed of the roller (that is, the heating time), and the surface properties and materials of the transfer body 18.

For example, if the temperature, pressure, time, etc. mentioned above are insufficient for the surface quality and thickness of the transfer member 12, sufficient transfer cannot be performed. On the other hand, if the temperature is excessive, the molten ink will flow out into the surrounding area, resulting in ink "bleeding".
will occur.

Further, as described above, an iron or a hot plate can be used instead of the heat roller 19 in the second step.

However, with this method, temporal control is more difficult than with a heated roller, and image quality deterioration due to ``bleeding'' becomes significant. It is convenient to expose the intermediate transfer body 12 and the transfer body 18 to light with the light source 21 to generate heat, thus heating the ink image 12a on the intermediate transfer body 12. The heating time when using the heat roller 19 is generally 10-odd mg@Q to several tens of milligrams.
0m5ec, and when using an iron, it is several 11@
However, when heat generation due to exposure is utilized as described above, the time required for heating is short. For example, if a flash light source such as a xenon lamp is used, 2 to 3 fifi@
(Heating is performed in an extremely short period of time as shown in B. As a result, the melting transfer operation is performed in a shorter time than the time it takes for the ink to melt and flow out, and the occurrence of "bleeding" is prevented.

Note that if you try to heat the ink image in the second step by exposure in this way, you will end up performing the same work as the exposure in the first step.
In the first step, the original 16 is exposed to light on the ink sheet 15.
This is done through the ink layer 14 of . Here, since the ink layer 14 absorbs light in a specific wavelength range, if the wavelength of the exposure light falls within this specific wavelength range, the ink in the ink layer 14 will melt due to exposure regardless of the image 16a. The image is transferred to the intermediate transfer body 12. Therefore, the exposure amount in the first step is at least enough to melt the ink due to the heat generated by the document image 16m, and at most the ink in the ink layer 14 is not melted, that is, the ink on the background part of the image is melted. The amount can be determined as much as possible.

On the other hand, the exposure in the second step is performed on the intermediate transfer body 12.
Since the purpose is to dissolve the upper ink image 2a itself, it is necessary that the exposure amount be higher than the exposure amount in the first step.

When heating the ink image 12a in the second step by exposure, the exposure can be used more effectively if the intermediate transfer body 12 is transparent. Furthermore, since exposure, especially flash exposure, requires a short time for heating, the transfer of heat from the ink layer 14 to other parts can be almost ignored, and therefore the surface properties of the transfer body 18 itself There is no need to give special consideration to heat capacity, etc. Further, since there is no need to hold the transfer body 18 etc. with rollers or the like, glass, metal, or the like having a sufficient three-dimensional thickness can be used as the transfer body 18. That is, it is possible to transfer onto the surfaces of these glasses and the like.

In addition, in FIG. 4, for the sake of explanation, the intermediate transfer body 12 and the transfer body 1 are
8 is shown separated, but in reality, both are pressed against each other.

According to this embodiment, since exposure is used in both the first step and the second step, it is possible to use common equipment, which is advantageous in terms of equipment costs.

Through the above explanation, the thermal transfer copying method according to the present invention has been understood in principle. Next, a description will be given of an apparatus that actually utilizes the method of this invention, that is, a copying apparatus.

FIG. 5 is a perspective view of a portable copying device 51, which is an example of such a copying device. As shown in the figure, the portable copying device 51 includes, from above the device, an electrical control section 52 with electronic components incorporated on a board, an operation section 55 such as a display lamp switch, etc.
It has a charging part 54 mainly consisting of a capacitor etc. that stores the light emission energy of a flash lamp, a light emitting part 55 having a flash lamp 11 as a light source, a reflecting plate 82, etc., and a translucent platen plate 61, a translucent buffer member 62, etc. Translucent platen portions 56 are arranged in a stacked manner.

As shown in FIG.
This is the part that presses the transfer sheet 77 and the transfer sheet 77 when they are closely layered. The transfer sheet 77 is previously formed integrally by bringing the intermediate transfer body 12 and the ink sheet 15 into close contact with each other, as shown in FIG. The ink sheet 15 is connected to the ink support 13 and the ink 14 supported by it.
What is made of and is as explained in connection with FIG. A frame 75 is used between the intermediate transfer member 12 and the ink sheet 15 as necessary. The frame 75 is placed around the intermediate transfer body 12 as shown in FIG.

In FIG. 8, first, the transfer sheet 77 is placed on the original 16 to be copied so that the ink sheet 15 side is on the original 16 side. The portable copying device 51 is placed thereon so that the platen portion 56 is in close contact with the transfer sheet 77. The copying apparatus 51 is connected to a power source such as a commercial 100 V power source or a rechargeable battery, and the seven-lash charging capacitor is charged to a preset potential level by this power source.

Due to the weight of the copying device 51 and the pressure applied through the copying device 51, the platen portion 56 of the copying device 51 and the transfer sheet 77
, and each of the originals 16 is uniformly pressed and brought into close contact with each other. If the trigger switch of the 7 lash lamp is turned on in this state,
The flash lamp 11 emits light, and the original 16 is exposed through the platen section 56 and the transfer sheet 77.

The details of the subsequent copying work are the same as those described in connection with FIGS. 1 to 4.

(Effects) As described above, according to the present invention, it is not necessary for the light component effective for thermal transfer to pass through the document, unlike in conventional copying methods, and therefore it is possible to handle various forms of document. .

Since only the support of the ink sheet is present before the heat generated in the image area is transmitted to the ink layer, a good transferred image can be obtained with little heat diffusion. By using an intermediate transfer member, copying including reediting of images, which was impossible with conventional methods, becomes possible.

If the ink image on the intermediate transfer member is heated by exposure in the second step, the heating operation can be completed within a short time, and "bleeding" due to ink leakage can be prevented.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the principle of the first step of the copying method according to the present invention, FIG. 2 is an explanatory diagram of the second step of the copying method, and FIG.
The figure is an explanatory diagram showing a method of separating the intermediate transfer member and the ink sheet in the same copying method, FIG. 4 is an explanatory diagram of another example of the second step, and FIG. 5 is a copying apparatus that executes the copying method according to the present invention. FIG. 6 is a cross-sectional view of a transfer sheet having an intermediate transfer body and an ink sheet, FIG. 7 is a perspective view of this transfer sheet, FIG. 8 is an explanatory diagram of how to use this copying apparatus, FIGS. 9 and 10 are diagrams showing a conventional copying method. 14... Ink layer 13... Ink support 1
5... Ink sheet, 16... Original 12... Intermediate transfer body 12a... Ink image 18-... Transfer body 19... Heating roller 11.21-... Light source

Claims (4)

[Claims] (1) An original is laminated on the ink support side of an ink sheet equipped with a heat-fusible ink layer and an ink support that supports the hot-fusible ink layer, and an intermediate transfer body is laminated on the ink layer side of the ink sheet. The first step is to selectively melt the ink by exposure to light and obtain an ink image that is a mirror image of the original on the intermediate transfer body. A thermal transfer copying method comprising a second step of transferring onto a transfer body. (2) In the second step, the overlapped intermediate transfer body and transfer body are passed between two rollers, at least one of which is heated, and the ink image is heated by the heated roller. A thermal transfer copying method according to claim 1. (3) The thermal transfer copying method according to claim 1, wherein in the second step, the ink image is heated by exposing the intermediate transfer member and the transfer member that are overlapped. (4) The thermal transfer copying method according to claim 3, wherein the light energy of the exposure in the second step is greater than the light energy of the exposure in the first step.