JPH071708A - Image transferring device - Google Patents

Abstract

PURPOSE:To prevent the pressing force due to the deflections of heat rollers from lowering by a simple structure. CONSTITUTION:On a guide plate 32, on the sides of which image sheet 26 and image receiving sheet 28 are placed respectively, convex surfaces, which makes the thickness of the guide plate gradually thicker in the direction of the axis lines of heat transferring rollers from the thicknesses (d) at both end parts of the rollers toward their axial middle parts, are made. The change of the thickness in the axial direction of the heat transferring rollers of the guide plate 32 corresponds to the amounts of deflection of the heat transferring rollers under the condition that the predetermined pressure are applied to the journal end parts of the heat transferring rollers. Thus, to the heat transferring rollers, between which and the guide plate 32 the image sheet and the image receiving sheet are pinched respectively, nearly uniform same stresses as the stresses F applied at the journal ends of the heat transferring rollers are acted axially, resulting in developing no decrease of pressing force between the image sheet and the image receiving sheet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image transfer device for transferring an image by applying a predetermined pressure between an image sheet and an image receiving sheet which are held on a support plate.

[0002]

2. Description of the Related Art When a printing plate is prepared from a color original using a plate-making material such as a PS plate, and a large number of printed matter is prepared by this printing plate, a color proof is prepared prior to printing to perform a plate inspection work. It is normal to do. As a light-sensitive material for making this color proof, a silver salt photographic light-sensitive material, an electrophotographic light-sensitive material, a light-sensitive material using a photopolymer, etc. are known. When making a color proof, it becomes an original. A color image is color-separated, and development processing is performed for each color to form a colored image of each color on the photosensitive material, and then these colored images are transferred to a transfer target sheet (hereinafter referred to as "image receiving sheet") Calibrate.

In this case, four colored originals (hereinafter referred to as "image sheets") of black, cyan, magenta, and yellow are prepared on each photosensitive material using four photosensitive materials, and these are sequentially made the same. A color proof can be created by superposing and transferring the image on the image receiving sheet.

When producing such a color proof, there is a method in which the image formed on the image sheet is transferred to the image receiving sheet by heating while heating the image sheet and the image receiving sheet. As an apparatus for producing a color proof by such a method, an image sheet and an image receiving sheet are integrally sandwiched by a pair of heat rollers heated to a predetermined temperature by an internal heat source, and an image to which pressure is applied while heating is applied. There is a transfer device.

In such an image transfer device, when the image receiving sheet and the image sheet are integrally nipped and conveyed by the pair of heat rollers, the image receiving sheet and the image sheet are integrally heated by the heat of the heat rollers. Along with this, a predetermined pressure is applied between the image receiving sheet and the image sheet by the sandwiching force applied between the pair of heat rollers.
As a result, the transferred image recorded on the image sheet is transferred to the image receiving sheet.

[0006]

However, when an attempt is made to apply pressure by sandwiching the image receiving sheet and the image sheet by the pair of heat rollers, the heat roller is slightly deflected, and the heat roller has a slight axial deflection. The pressing force will decrease. For this reason, in order to apply a desired considerably large pressing force to the front surface between the image sheet and the image receiving sheet, it is necessary to apply a large pressure to the shaft end portion of the heat roller. There must be.

In order to prevent the bending of the heat roller pair, there is a method of suppressing the intermediate portion in the axial direction by a backup roller or the like so as not to cause the bending on the opposite sides of the heat rollers. The structure of the device becomes complicated.

Further, as a method for eliminating the uneven pressure distribution due to the bending of the heat roller, a so-called crown roller in which the diameter of the middle portion of the heat roller is gradually increased can be used. The production of
Considering the amount of deflection, it is necessary to perform extremely precise processing to bend the surface smoothly, leading to an increase in the cost of the heat roller.

The present invention has been made in consideration of the above facts, and it is an object of the present invention to provide an image transfer device which has a simple structure and prevents a decrease in pressing force due to bending of a heat roller.

[0010]

According to a first aspect of the present invention, in an image transfer device, an image sheet and an image receiving sheet which are superposed and held on a support are heated and pressed while being nipped and conveyed by a heat roller, An image transfer device for transferring the transferred image to an image receiving sheet, wherein the support has a thickness distribution along the axial direction of the heat roller that changes in accordance with the bending of the heat roller. And

The image transfer apparatus according to claim 2 of the present invention is
The image transfer apparatus according to claim 1, wherein a surface of the support opposite to a side holding the front image image sheet and the image receiving sheet is a convex surface according to the bending of the heat roller.

[0012]

In the image transfer apparatus according to the first aspect of the present invention,
The thickness of a supporting plate for overlapping and holding the image sheet and the image receiving sheet is changed according to the bending of the heat roller. For example, both end portions have a predetermined thickness, and the middle portion is thickened according to the bending of the heat roller.

As a result, when the support plate holding the image receiving sheet and the image sheet is sandwiched by the pair of heat rollers and pressure is applied, the middle portion of the heat rollers bends,
The outer peripheral portion of the heat roller is not separated from the surface of the support plate, and the bending of the heat roller can be substantially eliminated.

With this, the image receiving sheet and the image sheet can be pressed together with the support plate with a substantially uniform pressure along the axial direction, and a desired pressure can be obtained without applying a large pressure to the shaft end portion of the heat roller. Can be added between and the image sheet.

In the image transfer apparatus according to the second aspect of the present invention, only the surface of the support plate opposite to the surface holding the image receiving sheet and the image sheet is a convex surface corresponding to the bending of the heat roller. Thereby, the image receiving sheet and the image sheet can be placed on the flat surface of the supporting plate, and even the supporting plate whose thickness changes along the axial direction of the heat roller,
The image receiving sheet and the image sheet can be held on a flat surface in a stable state, and the registration between the image receiving sheet and the image sheet can be surely performed.

As described above, according to the present invention, by simply processing the image receiving sheet and the supporting plate to be inserted together with the image sheet between the heat rollers, the bending of the heat roller can be substantially eliminated and the image can be received in the optimum state. A pressing force can be applied between the sheet and the image sheet.

[0017]

1 and 2 show an image transfer device 10 which is an embodiment of the present invention. 1 is a schematic configuration view of the image transfer apparatus 10 as seen from the left side surface, and FIG. 2 is a schematic exploded perspective view of the image transfer apparatus 10.

In this image transfer device 10, a working portion 18, a transfer portion 22, and a receiving portion 24 are sequentially arranged along the longitudinal direction of a pair of side plates 14 and 16 provided upright on the machine base 12.

In the working section 18, a work table 30 is arranged between the side plates 14 and 16. Both sides of the workbench 30 are supported by the side plates 14 and 16, and a guide plate 32 is mounted on the upper surface of the workbench 30 so as to slide between the both side plates 14 and 16. On the guide plate 32, the image receiving sheet 28 and the image sheet 26 on which the image is printed are aligned (registered) and arranged in an overlapping manner, and the guide plate 32 is moved to move them from the working unit 18 to the transfer unit 22, Receiver 2
4 and the image on the image sheet 26 is transferred to the image receiving sheet 28. Note that the registration between the image sheet 26 and the image receiving sheet 28 may be performed by using, as a mark, the registration mark recorded at a predetermined position on the image sheet 26 together with the transferred image. 26 and the image receiving sheet 28 are provided with positioning holes at predetermined positions, and the pins of the positioning device are inserted into these positioning holes so that the image sheet 26 and the image receiving sheet 28 are registered. It may be.

As the image sheet 26, there are used four image sheets 26 on which transfer images of black, cyan, magenta and yellow are formed via a mask original obtained by color-separating a color original. The image sheet 26 is superposed on one image receiving sheet 28, and a predetermined temperature and pressure are applied to transfer the image on the image sheet 26 to the image receiving sheet 28. By performing this work on the four image sheets 26 in order, a color image can be formed on one image receiving sheet 28 for performing the plate inspection work.

The guide plate 32, which is a support plate, uses a planographic plate made of aluminum. As shown in FIG. 3, the guide plate 32 has a flat surface on which the image receiving sheet 28 and the image sheet 26 are placed (the surface on the upper side of the paper surface shown in FIG. 3).
The opposite lower surface may be a curved surface that is curved so that the central portion in the conveyance width direction (arrow B direction) projects. For example, the relationship between the thickness d of both ends of the guide plate 32 in the conveyance width direction and the thickness of the central portion is based on the amount of bending when the heat transfer rollers 94 and 96 of the transfer unit 22 described later sandwich the guide plate 32. Is decided.

As shown in FIG. 2, one end of the cover sheet 20 is attached to the tip of the guide plate 32 placed on the work table 30 on the side where it is inserted into the transfer portion 22, and the guide plate 32 is attached to the guide plate 32. After arranging the image receiving sheet 28 and the image sheet 26 in an overlapping manner, these are covered with the cover sheet 20,
The image sheet 26 and the image receiving sheet 28 are protected.

As shown in FIG. 1, an insertion mechanism 62 is arranged below the work table 30 of the work section 18. Figure 2
As shown in, a pair of side plates 64 and 66 having an L-shaped cross section are attached to the insertion mechanism 62 so as to face each other. Two shafts 68 and 70 are hung between the side plates 64 and 66 and are axially supported. Shaft 6
Sprockets 72 are arranged near the side plates 64 and 66 at both ends of the sprockets 8 and 70, and a chain 74 is wound around the sprockets 72 facing each other. A sprocket 76 is fixed to the shaft 68 near one of the sprockets 72.
A chain 80 is wound around the sprocket 78A (shown in FIG. 1) attached to the drive shaft of the motor 78 (shown in FIG. 1). The motor 78 is fixed (not shown) to the lower surface side of the workbench 30, and the drive of the motor 78 causes the chain 74, which is wound around both ends of the shafts 68 and 70, to integrally rotate.

On the workbench 30 side of the chain 74, an insertion bar 82 is hung between the side plates 74 and 76, and is movably connected to the workbench 30 in parallel along a slit formed in the side plates 74 and 76. A plurality of insertion pins 84 are projected on the upper surface side of the insertion bar 82. The tips of these insertion pins 84 are inserted into the moving holes 30 </ b> A formed in the workbench 30 and project from the upper surface of the workbench 30. Work table 30
The moving hole 30A is formed long along the transport direction (direction of arrow A), and the insertion bar 82 is driven by the forward rotation and the reverse rotation of the motor 78, and the insertion pin 84 is moved into the moving hole 3.
It is designed to reciprocate in 0A.

Insertion pin 8 protruding from this moving hole 30A
The tip end of No. 4 is arranged so that the end surface of the guide plate 32 placed on the workbench 30 on the opposite side of the transfer portion 22 comes into contact, and the insertion pin 84 moves to the transfer portion 22 side in this state. Thus, the guide plate 32 is pushed and inserted into the transfer portion 22.

A notch 86 is formed in the side plate 14, 16 at a position corresponding to the transfer portion 22. A pair of housing plates 88 are attached to the notches 86, respectively. As shown in FIG. 1, the housing plate 88
Between the halogen lamps 150, 15 on the working unit 18 side.
2 are arranged vertically in pairs with the passage of the guide plate 32 interposed therebetween,
Behind the halogen lamps 150 and 152, reflectors 154 and 156 having a substantially U-shaped cross section are arranged, and a preheat zone 158 is constituted as a whole. The halogen lamps 150 and 152 are controlled by a control unit 160, which will be described later, to turn on / off and generate heat.

A pair of heat transfer rollers 94 and 96 are disposed adjacent to the preheat zone 158 of the transfer section 22. The heat transfer roller 96 is attached to the housing plate 88 while being prevented from moving downward, and has a structure for supporting the heat transfer roller 94 arranged above.

The guide plates 32 passing through the preheat zone 158 together with the image sheet 26, the image receiving sheet 28 and the cover sheet 20 are heated by the radiant heat from the halogen lamps 150 and 152 and the radiant heat from the reflectors 154 and 156, and are paired. It is inserted between the heat transfer rollers 94 and 96. At this time, the image receiving sheet 28 and the image sheet 2
In No. 6, the temperature rises and they are lightly adhered to each other, and when they are sandwiched by the heat transfer rollers (heat rollers) 94 and 96 in the next step, they are not displaced from each other.

As shown in FIG. 2, the heat transfer roller 9
Nos. 4 and 96 are generally-used in which the outer peripheral surface of a substantially cylindrical core metal having a hollow inside is covered with an elastic body such as a rubber coating layer, and shaft end members 162 are press-fitted and fixed to both axial end portions. Uses hollow rollers. Heat transfer rollers 94, 9
Reference numeral 6 constitutes a heat roller in which a rod-shaped heater 98 is coaxially provided inside the hollow, and the outer peripheral surface thereof is the heater 98.
Is heated to a predetermined temperature.

The heat transfer roller 96 has a shaft end member 162 axially supported by the housing plate 88 by a bearing (not shown) attached to the housing plate 88. Further, the heat transfer roller 94 is supported by a bearing (not shown) whose shaft end member 162 is attached to the small plate 164, and the small plate 164 is fitted and attached to the notch 168 formed in the housing plate 88. Is supported by the housing plate 88. The heater 98 inside the heat transfer rollers 94 and 96 is provided with the bearing member 16
The end portion pulled out from No. 2 is attached to the housing plate 88 through the support member 168, and the heat roller itself does not rotate but only the heat roller main body rotates.

As shown in FIG. 2, in the notch 168 of the housing plate 88 in which the small plate 164 is fitted,
A pressure mechanism 170 is attached. Pressure mechanism 170
When the small plate 164 tries to move in a direction in which the small plate 164 is separated from the heat transfer roller 96, the small plate 164 is moved by the internal spring (not shown).
It is adapted to be urged toward the 6 side with a predetermined pressure.

Therefore, in the state where the guide plate 32 on which the image sheet 26 and the image receiving sheet 28 are placed is not inserted between the heat transfer roller 94 and the heat transfer roller 96,
It is in a state of being in contact with the heat transfer roller 96 by its own weight. Further, when the heat transfer roller 94 is about to be separated from the heat transfer roller 96 by inserting the guide plate 32 on which the image sheet 26 and the image receiving sheet 28 are placed between the heat transfer roller 96, the pressing mechanism. 170
Energize the small plate 164. As a result, the image sheet 26 and the image receiving sheet 28 sandwiched between the heat transfer rollers 94 and 96 are pressed together with the guide plate 32 from above and below. In addition, the pressing force at this time is the pressing mechanism 1
The urging force of 70 on the small plate 164 can be adjusted and changed.

A sprocket 100 is attached to the tip of the shaft end member 162 of the heat transfer roller 96 on the lower side outside the housing plate 88. Further, a motor 102 is arranged near the housing plate 88, and the sprocket 10 is attached to the output shaft of the motor 102.
2A is attached. A chain 104 is wound around the sprocket 100 and the sprocket 102A. Therefore, the driving force of the motor 102 is transmitted by the chain 104 to rotate the heat transfer roller 96, and further, the heat transfer roller 94 in contact with the heat transfer roller 96 rotates following the rotation. Therefore, when the motor 102 is driven to rotate in the normal direction or the reverse direction, the guide plate 32 sandwiched by the heat transfer rollers 94 and 96 moves from the working unit 18 to the receiving unit 24 or from the receiving unit 24 to the working unit 1.
Transported in 8 directions. The heat transfer rollers 94, 96
The periphery of is covered with a cover (not shown) to prevent heat from being unnecessarily released to the outside.

In this embodiment, in consideration of the characteristics of the image receiving sheet 28 and the image sheet 26, the heating temperature of the heat transfer rollers 94 and 96 in the transfer section 22 is set to about 120 ° C.
The transfer image of the image sheet 26 is set to 130 ° C. and the conveying speed is about 90 cm / min so that the transfer image of the image sheet 26 can be transferred to the image receiving sheet 28 in an optimum state. A minimum pressure of about 4 Kgf / cm ² necessary for sure transfer to the image receiving sheet 26 is applied by the pressure mechanism 170. In addition, this setting value is
It is more preferable to set the temperature in consideration of the temperature and humidity in the working environment.

As shown in FIG. 2, the working unit 1 of the transfer unit 22.
The receiving portion 24 provided on the opposite side of the side plate 8 is the side plate 14,
It is provided with a pedestal 112 which is mounted so as to be stretched between the sixteen. The pedestal 112 has a pair of long holes 114 penetrating through the front and back sides at the end opposite to the transfer unit 22 along the transport direction. The contact pins 118 of the insertion mechanism 116 are inserted into the elongated holes 114.

The insertion mechanism 116 is arranged on the lower surface side of the pedestal 112, is pivotally supported by a pair of L-shaped brackets 120 mounted on the lower surface side of the pedestal 112, and the conveyance direction of the guide plate 32 is in the axial direction. Shaft 1 arranged along the direction
22 is provided. Both ends of the shaft 122 project to the outside of the bracket 120, and blocks 124 are fixed to the respective tip ends. A contact pin 118 is projectingly provided on these blocks 124.

A sprocket 126 is attached to an intermediate portion of the shaft 122, and a chain 130 is wound around the sprocket 126 between the sprocket 128A attached to the output shaft of the motor 128. . The motor 128 is attached to the lower surface of the pedestal 112 via a bracket 132.

Accordingly, the block 124 rotates together with the shaft 122 by the driving of the motor 128, whereby the contact pin 118 projects from the elongated hole 114 to the upper surface of the pedestal 112 and moves toward the transfer portion 22 side while rotating. Then, at the end of the long hole 114 on the transfer section 22 side, the pedestal 112 is
It is designed to move to the bottom side of. This contact pin 1
By the rotational movement of 18, the guide plate 32 placed on the pedestal 112 is pushed toward the transfer section 22 and inserted into the transfer section 22.

The operation of the image transfer device 10 is performed by the control unit 1.
Controlled by 60. As shown in FIG.
0 is equipped with a microcomputer 190 to which a CPU 180, a ROM 182, a RAM 184 and an I / O port 186 are connected by a bus 188. The microcomputer 190 includes a motor 78 of the insertion mechanism 62 of the working unit 18, a transfer unit 2
2 halogen lamps 150, 152, heat transfer roller 9
The heater 98 and the motor 102 of 4, 96 and the motor 128 of the insertion mechanism 112 of the receiving portion 24 respectively drive the drivers 192A, 192B, 192C, 192D, 192E, and 192A.
They are connected via 192F and 192G and are controlled by the microcomputer 190.

In the control unit 160, the workbench 3 of the work unit 18
The guide plate 32 placed on 0 is sent to the transfer section 22 by the insertion mechanism 62, and is sent out while being transferred to the receiving section 24 by the heat transfer rollers 94 and 96 in the transfer section 22. At this time, in the transfer section 22, the heat transfer roller 9
4, 96, the image sheet 26 together with the guide plate 32.
The image receiving sheet 28 is heated while being pressed, and the image recorded on the image sheet 26 is transferred to the image receiving sheet 28. In the receiving section 24, the guide plate 32 in the shape of the receiving table 112 is sent to the transfer section 22 by the insertion mechanism 116, and the work table 3 of the working section 18 is transferred from the transfer section 22.
It is designed to send out 0.

A temperature sensor 194 for detecting the temperature outside the machine is connected to the microcomputer 190, and the halogen lamp 1 is set to a temperature stored in advance according to the temperature outside the machine.
Halogen lamps 150, 152 by heating 50, 152
The radiant heat of the guide plate 32 heats the surface of the guide plate 32 passing through the preheat zone 158 to a predetermined temperature.

Next, the operation of this embodiment will be described. When a power switch (not shown) of the image transfer device 10 is turned on, the motor 102 is driven to rotate the heat transfer rollers 94 and 96. In addition, the insertion pin 84 of the insertion mechanism 62 of the working unit 18
Has moved to the end of the through hole 30A on the side opposite to the transfer portion 22. At the same time, the heater 98 of the heat transfer rollers 94 and 96 of the transfer unit 22 is energized.

After that, the image receiving sheet 28 and the image sheet 26 are superposed on the guide plate 32 placed on the workbench 30 of the working unit 18, the registration is performed, and then the cover sheet 20 covers them. At this time, a squeeze mechanism for removing air from between the cover sheet 20 and the image sheet 26 may be provided.

Next, when the transfer operation is started, the motor 74 of the insertion mechanism 62 is driven to insert the insertion pin 84 into the through hole 30.
It is moved toward the transfer portion 22 in A. by this,
The guide plate 32 is pressed toward the transfer portion 22, and the image sheet 26 and the image receiving sheet 28 together with the guide plate 32 pass through the preheat zone 158. Preheat zone 158
Then, when the insertion of the guide plate 32 is detected, the temperature outside the machine measured in advance by the temperature sensor 194 (temperature under the working environment), that is, the temperature outside the machine can be regarded as the temperature of the guide plate 32. The heat generation amount of the halogen lamp is adjusted to a preset and stored temperature according to this temperature.

The guide plate 32 has a preheat zone 158.
When it passes through, it is heated to a predetermined temperature by the radiant heat from the halogen lamps 150 and 152, and is inserted between the heat transfer rollers 94 and 96. Since the guide plate 32 is heated by the halogen lamps 150 and 152,
Immediately when it is inserted between the heat transfer rollers 94 and 96, it is heated to a necessary temperature, so that it becomes possible to raise the temperature between the image sheet 26 and the image receiving sheet 28 to a temperature required for transfer. At this time, the image sheet 26 and the image receiving sheet 28 are also heated, and are in a state of easily adhering to each other,
There is no deviation when inserted between the heat transfer rollers 94 and 96.

The heat transfer roller 94 together with the guide plate 32,
Image receiving sheet 28 and image sheet 26 inserted between 96
Is conveyed while being heated and pressurized while being sandwiched by the heat transfer rollers 94 and 96. At this time, the image receiving sheet 2
8 and the image sheet 26 are heated by the heat transferred from the surfaces of the heat transfer rollers 94 and 96, and the pressing force from the heat transfer rollers 94 and 96 acts on the image transfer sheet 8 and the image sheet 26.
The transferred image formed on the sheet is adhered to the image receiving sheet 28 and transferred.

From the transfer section 22 to the heat transfer rollers 94, 96
The guide plate 32 sandwiched and conveyed by the
It is placed on the receiving table 112 of the receiving portion 24. Receiver 24
The guide plate 32 placed on the pedestal 112 is sent to the transfer unit 22 this time by the contact pin 118 that is moved by the drive of the motor 28 of the insertion mechanism 116 of the receiving unit 24. At this time, in the transfer unit 22, the rotation of the motor 102 is reversed, and the guide plate 32 fed from the receiving unit 24 is nipped by the heat transfer rollers 94 and 96 and conveyed toward the work table 30 of the work unit 18. Then, the image receiving sheet 28 and the image sheet 26 together with the guide plate 32 are returned to the work table 30 of the working unit 18. After reversal, halogen lamp 150, 1
No heating by 52 is necessary, and the halogen lamp 150,
152 is off.

In this way, when one transfer is completed, the cover sheet 20 is rolled up and the image sheet 26 after transfer is peeled off from the image receiving sheet 28, and the image receiving sheet 2
The image sheet 26 on which the next transferred image is formed is aligned with the sheet 8 and is placed on the guide plate 32 to perform the transfer operation.
By repeating this, a predetermined colored image can be formed on the image receiving sheet 28.

In the transfer section 22, the image transfer sheet 9 and the image receiving sheet 28 placed on the guide plate 32 are transferred to the heat transfer roller 9.
Before transferring under pressure while heating at 4, 96, the halogen lamp 15 is passed through the preheat zone 158.
0, 152 heats the image sheet 26, the image receiving sheet 28, and the guide plate 32 to a predetermined temperature. Therefore, the heat transfer rollers 94 and 96 are used to guide the guide plate 3.
When the image sheet 26 and the image receiving sheet 28 are heated while being pressed together with 2, the temperature of the guide plate 32 does not rise as expected, and the temperature between the guide plate 32 affects the temperature between the image sheet 26 and the image receiving sheet 28. It is possible to prevent such a problem that the temperature becomes lower than the desired temperature.

That is, as shown in FIG. 4, when the guide plate 32 in the working environment is conveyed while being sandwiched by the heat transfer rollers 94 and 96, the guide plate 32 in the low temperature environment is not preheated. Heating transfer roller 94,
When heated by 96, the temperature of the surface of the guide plate 32 becomes only E, which is greatly reduced from the optimum temperature D. In FIG. 4, the solid line indicates the guide plate 32 in this embodiment.
~ The temperature distribution between the cover sheets 20 is shown, and the one-dot chain line shows the temperature distribution when the guide plate 32 is processed by a conventional device that does not preheat. At this time, between the image sheet 28 and the image receiving sheet 26 that affect the transfer of the image,
Because of the influence of the guide plate 32, the temperature G is only considerably lower than the optimum temperature D, and the transferred image on the image sheet 26 cannot be transferred to the image receiving sheet 28 under the optimum temperature condition.

On the other hand, in this embodiment, the guide plate 3
2 is preheated to a predetermined temperature in the preheat zone 158, the temperature between the image sheet 26 and the image receiving sheet 28 heated by the heat transfer rollers 94 and 96 is set to the transfer target recorded on the image sheet 26. The temperature D can be set to the optimum temperature for transferring the image to the image receiving sheet 28.

In this embodiment, the temperature sensor 194 measures the temperature or temperature / humidity of the work environment, and the heat transfer rollers 94 and 96 measure the guide plate 3 during image transfer.
Although the surface temperature of 2 is set to a predetermined temperature,
The temperature of the guide plate 32 inserted into the preheat zone 158 is directly detected, and the temperature of the guide plate 32 inserted between the heat transfer rollers 94 and 96 is set to a preset temperature regardless of the temperature under the working environment. You may make it raise to. Further, the halogen lamps 150 and 152 for preheating may be provided only on the lower side facing the guide plate 32 when only the guide plate 32 needs to be heated.

Further, in the preheat zone 158, the halogen lamps 150 and 152 may be used to heat the image sheet 26 and the image receiving sheet 28 together with the guide plate 32 to the optimum temperature for image transfer. The rollers 94 and 96 may be configured to apply a predetermined pressing force while preventing a temperature decrease between the image receiving sheet 28 and the image sheet 26.

Further, in this embodiment, not only the heat generation state of the halogen lamps 150 and 152 is controlled according to the temperature outside the machine, but also the driving speed of the heat transfer rollers 94 and 96 may be controlled. In the preheat zone 158, the image receiving sheet 28 and the image sheet 26 are previously formed together with the guide plate 32.
Since they are also heated, if they are further heated by the heat transfer rollers 94 and 96, the space between the image sheet 26 and the image receiving sheet 28 can be raised to the optimum temperature C (approximately temperature D) in a short time. A predetermined pressing force may be applied between the image sheet 26 and the image receiving sheet 28 in this optimum temperature state, so that the drive speed of the motor 128 is increased to guide the guide plate 3.
2 may be passed through the transfer portion 22.

Next, the pressing force applied between the image receiving sheet 28 and the image sheet 26 by the heat transfer rollers 94 and 96 will be described.

When the image sheet 26 and the image receiving sheet 28 together with the guide plate 32 are nipped by the heat transfer rollers 94, 96, the nip force between the pressure transfer mechanism 170 and the heat transfer rollers 94, 96 via the shaft end member 162. Is added. At this time, the heat transfer rollers 94 and 96 may be bent, and the pressing force at the intermediate portion in the axial direction may decrease.

On the other hand, in this embodiment, as shown in FIG. 3, the surface opposite to the surface on which the image receiving sheet 28 is placed is curved so that the intermediate portion of the guide plate 32 in the conveying width direction becomes thick. ing. Therefore, even if the heat transfer rollers 94 and 96 are bent, the axes of the heat transfer rollers 94 and 96 are not substantially separated from the surface of the guide plate 32 that faces them, and the heat transfer rollers 94 and 96 are not separated. It is possible to prevent the distribution of the pressing force of 96 from becoming nonuniform along the axial direction.

That is, as shown in FIG. 5, the stress, which is the reaction force against the pressing force, will be described. When the heat transfer rollers 94 and 96 are bent, a predetermined amount is applied to both ends in the axial direction. Although the stress F is generated, the stress at the intermediate portion in the axial direction is greatly reduced (shown by the chain double-dashed line).

On the other hand, in this embodiment, the guide plate 32
The thickness f of the intermediate portion of the heat transfer rollers 94 and 96 is changed in consideration of the amount of bending of the heat transfer rollers 94 and 96.
Does not change the stress of the heat transfer roller 94. Therefore, the image sheet 26 and the image receiving sheet 28
It is possible to prevent a change in the pressing force between the image sheet 26 and the image receiving sheet 28 by applying a predetermined pressure between the image sheet 26 and the image receiving sheet 28 and transfer the transferred image recorded on the image sheet 26 to the image receiving sheet 28. it can.

In this embodiment, the surface of the guide plate 32 opposite to the surface on which the image receiving sheet 28 is placed is curved.
If there is no problem in registering the image receiving sheet 28 and the image sheet 26, the surface on the image receiving sheet 28 side may be curved,
Both surfaces may be curved to ensure a predetermined thickness f.

Further, when a support plate or the like for sandwiching the guide plate 32 together with the heat transfer roller 94 is provided in place of the heat transfer roller 96 so that the member facing the lower surface side of the guide plate 32 does not bend, The thickness f of the guide plate may be set, for example, as the amount of bending and the thickness d of the end portion in consideration of the bending amount of only the heat transfer roller 94 in which the guide plate 32 is curved. As a result, the image sheet 26 and the image receiving sheet 28 can be pressed substantially uniformly with a predetermined pressing force along the conveyance width direction, and a pressing force optimum for transfer can be applied between the image sheet 26 and the image receiving sheet 28. it can.

Further, in order to apply a predetermined pressing force between the image sheet 26 and the image receiving sheet 28 by the heat transfer rollers 94, 96, the shaft end member 162 of the heat transfer roller 94 is applied.
Since it is not necessary to set a particularly large pressure to be applied to the heat transfer rollers 94 and 96, it is possible to allow a sufficient margin for mounting the heat transfer rollers 94 and 96, and it is not necessary to have a strong structure for applying a large pressing force. In order to prevent the thermal transfer rollers 94 and 96 from bending, the thermal transfer roller 9
Since it is not necessary to specially provide a mechanism for preventing bending around 4 and 96 and suppress the decrease in pressing force of the heat transfer rollers 94 and 96, the structure of the apparatus can be simplified. .

Further, as a structure for preventing the bending of the roller, for example, a so-called crown is formed in which the outer peripheral portion of the roller is gradually expanded in the axial direction from the shaft end to the intermediate portion to form a substantially barrel shape. When performing, extremely high processing accuracy is required,
Although it will increase the cost of the device, it is not necessary to use such a roller with crown processing,
The cost increase of the device for preventing the bending of the roller can be suppressed.

The image transfer apparatus 1 applied to this embodiment
The transfer unit 22 and the heat transfer rollers 94 and 96 of No. 0 represent an example of the present invention, and do not limit the configuration of the image transfer apparatus to which the present invention is applicable. The present invention can be applied to an image transfer device having a general structure in which a predetermined temperature and a pressing force are applied to the image sheet and the image receiving sheet, which are placed together, and the transferred image formed on the image sheet is transferred to the image receiving sheet.

[0065]

As described above, in the image transfer apparatus according to the present invention, the heat roller is bent only by placing the image sheet and the image receiving sheet and processing the support plate inserted between the heat rollers. It can be resolved.

In addition to this, when a desired pressure is applied between the image receiving sheet and the image sheet, it is not necessary to apply a large pressure to the heat roller, so that the apparatus is made firm and the heat roller is prevented from bending. It is possible to obtain an excellent effect that it is not necessary to have a complicated structure.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an image transfer apparatus that is an embodiment of the present invention.

FIG. 2 is an exploded perspective view of a main part of the image transfer device of FIG.

FIG. 3 is a perspective view showing an example of a guide plate used in the present invention.

FIG. 4 is a graph showing a temperature distribution between a cover sheet and a guide plate sandwiched between heat transfer rollers and an image sheet and an image receiving sheet between them.

FIG. 5 is a front view of a heat transfer roller and a graph showing a stress distribution of the heat transfer roller.

FIG. 6 is a block diagram showing a schematic configuration of a control unit that controls the operation of the image transfer apparatus of the present invention.

[Explanation of symbols]

 10 image transfer device 18 working unit 22 transfer unit 26 image sheet 28 image receiving sheet 32 guide plate (support plate) 94, 96 heat transfer roller (heat roller)

Claims (2)

[Claims] 1. An image transfer device for transferring an image to be transferred of an image sheet onto an image receiving sheet by heating and pressing the image sheet and the image receiving sheet, which are superposed and held on a support, while being nipped and conveyed by a heat roller, An image transfer apparatus, characterized in that as the support, a support whose thickness distribution along the axial direction of the heat roller is changed according to bending of the heat roller is used. 2. The image transfer apparatus according to claim 1, wherein the surface of the support opposite to the side for holding the front image image sheet and the image receiving sheet is a convex surface according to the bending of the heat roller.