JPH01167757A - Pressurizing transfer device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of rimples and the stain of the surface of a roller by providing a gap forming member which forms a gap thinner than thickness obtained when a doner sheet is superposed on a receiver sheet and thicker than the thickness of the doner sheet. CONSTITUTION:The doner sheet 4 and the receiver sheet 5 pass between upper and lower rollers 1 and 2 and these sheets are pressurized with the pressures of the upper and lower rollers 1 and 2. And the images formed on the doner sheet is transferred to the receiver sheet 5. The thickness of a ring 3 is thinner than the thickness obtained when the doner sheet 4 is superposed on the receiver sheet 5 and thicker than that of the doner sheet 4. The ring 3 and the lower roller 2 are not in contact with each other while passing the doner sheet 4 and the receiver sheet 5, so that sufficient pressure is added. Meanwhile, when only doner sheet 4 intervenes, the ring 3 and the lower roller 2 are in contact with each other and the pressure is energized on the contact surface. Thus, the occurrence of the rimples and the stain of the surface of the roller can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention relates to a process in which a donor sheet and a receiver sheet are passed between a pair of pressure rollers in an overlapping manner, and an image on the donor sheet is transferred to the receiver sheet. This invention relates to a pressure transfer device.

(b) Conventional technology In a pressure transfer device in which a donor sheet and a receiver sheet are overlapped and passed between a pair of pressure rollers, an image is formed on the donor sheet through an exposure process, etc. Image transfer is performed onto the receiver sheet with the donor sheet and receiver sheet overlapped. Generally, in such a pressure transfer device, the pressure between the pressure rollers is often very high. For example, in the case where a light-receiving sheet coated with microcapsules containing a colorless dye and a photocuring agent is used as a donor sheet, and an image-receiving sheet coated with a developing material is used as a receiver sheet, the pressure between the pressure rollers is is 80-100 kg/
If the material is very high in da and does not roll, a large abnormal sound will be generated.This occurs when the rear end of the sheet leaves the rollers. This occurs as wrinkles on the other sheet when it has finished passing. Furthermore, if the donor sheet using the above-mentioned microcapsules is always held between rollers, and the receiver sheet is in the form of a cut sheet, there will be no exposure at all.
When the non-image area passes between the rollers, the microcapsules are destroyed and the dye inside flows out, causing a problem in that the flowed out dye contaminates the roller surface.

To deal with this problem, conventionally, both the donor sheet and the receiver sheet were supplied in rolls, and the sheet was cut after it passed the pressure roller, so that the two sheets were always sandwiched between the rollers. In order to prevent the formation of non-image areas, the control of the optical device for image forming exposure and the conveyance control of the donor sheet have been devised.

(C) Problems solved by the invention A However, from the viewpoint of handling the sheet, it is more convenient to configure the donor sheet in roll form, but the receiver sheet is supplied in a cassette like in a normal electrophotographic copying machine. It is preferable to make it into a cut sheet. Further, in a structure in which two sheets are always held between pressure rollers, there is a problem that wrinkles are more likely to occur because pressure is always applied to these sheets. Furthermore, constant pressure applied to the donor sheet may have an adverse effect on the donor sheet and the roller, such as contamination of the roller surface by liquid flowing out from the capsule. Furthermore, it is extremely difficult to control the formation of non-image forming areas.

An object of the present invention is to provide a pressurizer that can configure the donor sheet and the receiver sheet in the form of rolls and canted sheets, respectively, and that prevents pressure from being applied to the donor sheet when the receiver sheet does not pass between pressure rollers. An object of the present invention is to provide a pressure transfer device.

(d) Means for Solving the Problems This invention provides a pressure transfer method in which a donor sheet on which an image is formed and a receiver sheet that receives an image transfer from the donor sheet are passed between a pair of rollers in an overlapping manner. The apparatus is characterized in that a gap forming member is provided between the pair of rollers to form a gap that is thinner than the thickness when the donor sheet and receiver sheet are overlapped and thicker than the thickness of the donor sheet.

(81 action) In the pressure transfer device according to the present invention, a gap is formed between a pair of rollers that is thinner than the thickness of the donor sheet and the receiver sheet when they are overlapped, and is thicker than the thickness of the donor sheet. By providing the member, sufficient pressure is applied to the two sheets when they are passing between the pressure rollers, and no pressure is applied to the donor sheet when only the donor sheet is passing.

(f) Embodiment FIG. 1 shows an embodiment of the present invention. FIG. 3A shows a state in which the donor sheet and receiver sheet are held between a pair of pressure rollers, and FIG. 2B shows a state in which only the donor sheet is present between the pressure rollers.

The pressure roller is composed of an upper roller 1 and a lower roller 2, and pressure is applied between the upper and lower rollers by a pressure device (not shown). Rings 3, which are the gap forming members of the present invention, are provided at both ends of the upper roller 1. This ring 3 is made of a metal belt. A donor sheet 4 and a receiver sheet 5 pass between the upper and lower rollers 1 and 2.
, 2 pressurize these sheets. The image formed on the donor sheet is transferred to the receiver sheet 5 by this pressure. The thickness of the ring 3 is thinner than the thickness when the donor sheet 4 and the receiver sheet 5 are overlapped, and is thicker than the thickness of the donor sheet 4. Therefore, as shown in FIG. When the receiver sheets 5 are passing between the upper and lower rollers in a superimposed state, the ring 3 and the lower roller 2 do not come into contact with each other. Therefore, sufficient pressure is applied to the donor sheet 4 and the receiver sheet 5. On the other hand, when only the donor sheet 4 is interposed between the upper and lower rollers 1 and 2 as shown in Figure CB), the ring 3 and the lower roller 2 are in contact, and pressure is applied to this contact surface. At this time, the thickness of the ring 3 is the donor sheet 4
Because it is thicker than the thickness of the donor sheet 4, no pressure is applied to the donor sheet 4 interposed between the upper and lower rollers 1 and 2. In the figure, since no pressure is applied to the donor sheet 4, the donor sheet 4 becomes loose and A state in which the donor sheet 4 is not in close contact with the roller 1 is shown.

As the ring 3, a metal belt is used as the upper and lower rollers 1 and 2.
You may also use a roller wound around the upper and lower rollers 1 and 2.
It may be formed into a ring shape by cutting both ends of the ring. It is also possible to use an elastic ring made of hard rubber or the like instead of metal.

With the above configuration, the donor sheet 4 supply section can be configured as a roll, and the receiver sheet 5 can be configured in the form of a cut sheet. That is, even if the donor sheet 4 is always interposed between the upper and lower rollers 1 and 2, pressure is applied to the donor sheet 4 only in the state shown in FIG. 1(A). That is, as shown in FIG. 1(B), in some cases, only the donor sheet 4 is interposed between the upper and lower rollers, and no pressure is applied to the donor sheet 4.
Prevents wrinkles. Furthermore, if the donor sheet 4 is coated with microcapsules filled with a liquid substance, the surface of the upper roller 1 will be contaminated by the liquid substance that is broken and spilled out. can also be prevented. Further, when the rear end portion of the receiver sheet 5 in the form of a cut sheet passes the upper and lower rollers 1 and 2, the upper and lower rollers 1 and 2 are prevented from coming into contact with each other due to a large pressure. Because of this, a loud impact sound (abnormal sound)
will not occur. That is, the ring 3 acts as a buffer.

In the above structure, when the receiver sheet 5 is not between the upper and lower rollers, the ring 3 is pressurized, but if this state continues for a long time, the ring 3 may become deformed. When the receiver sheet 5 is not between the upper and lower rollers, the image forming operation is not performed, so the time during which the ring 3 is pressurized is generally long. Therefore, in order to prevent deformation of the ring 3, it is desirable to provide a mechanism for releasing the pressure on the upper and lower rollers when no image forming operation is being performed. That is, the ring 3 is connected to the receiver seat 5.
Immediately after the rear end comes off from between the upper and lower rollers, it acts as a cushion, and then the pressure release mechanism is immediately activated to separate the upper and lower rollers. In this way, it is possible to reduce the impact noise when the rear end of the receiver sheet 5 comes off the upper and lower rollers, and to prevent the ring 3 from being deformed.

FIG. 2 shows this pressure relief mechanism. The figure (A) shows a state in which the pressure release mechanism is not operating, and the figure (B) shows a state in which the pressure release mechanism is operating.

In the figure, 10 is an upper roller support member that supports the upper roller 1, and 11 is a lower roller support member that supports the lower roller 2. The shaft 12 is located approximately at the center of the lower roller support member 11.
The upper roller support member 10 is rotatably supported. Also, the upper roller support member 10 and the lower roller support member 11
A pressurizing spring 13 is placed between the right end portions. The elastic force of this spring 13 causes the upper and lower rollers l to move.

2 is pressurized. A roller 14 is supported at the left end of the lower roller support member 11, and a cam 15 that contacts this roller 14 is further provided. The shaft 16 of the cam 15 is connected to a drive mechanism (not shown), and the cam 1 is driven by a signal from a control section.
5 rotates by a predetermined angle. In FIG. 2(A), when the cam 15 is in the position indicated by the solid line in the figure, pressure is applied between the upper and lower rollers 1 and 2. From this state, the cam 15 is 90
When the cam 15 rotates counterclockwise, the cam 15 becomes in the state shown by the dashed line in the figure, and the lower roller support member 11 rotates clockwise about the shaft 12. Then, the lower roller 2 moves downward, and a gap is created between the upper and lower rollers 1 and 2, resulting in the state shown in FIG. 2(B).

The timing at which the motor (not shown) rotates and the cam 15 rotates counterclockwise from the state shown in FIG. 2(A).

The angle is set when the rear end of the receiver sheet 5 comes off the upper and lower rollers 1.2. In this case, immediately after the rear end of the seat sheet 5 comes off the upper and lower rollers 1 and 2, the ring 3 hits the lower roller 2 and reduces the impact noise.
Thereafter, the ring 3 separates from the lower roller 2 in the state shown in FIG. 2 CB). The state shown in FIG. 2(B) continues until the print switch of the image forming apparatus is pressed next. When the print switch is pressed down, the motor is driven again and the cam 15 rotates in the direction of the arrow in the figure, as shown in Figure 2 (A).
The state shown in is reached.

By providing the pressure release mechanism as described above, it is possible to prevent the ring from being pressurized when an image forming operation is not being performed, thereby eliminating deformation of the ring.

FIG. 3 shows a schematic configuration diagram of an image forming apparatus having the above-mentioned pressure transfer device.

Reference numeral 20 denotes an image forming apparatus main body, in which an upper roller 1 is disposed approximately in the center, and a lower roller 2 is disposed below this. A roll 21 of the donor sheet 4 is attached to a shaft 22 at the upper left side of the upper roller 1 . Further, a cassette 23 for storing the receiver sheet 5 is attached to the lower right side of the image forming apparatus main body 20, and a paper feed roller 24 is provided above the tip of the cassette 23, and a paper feed timing setting roller is provided downstream of the cassette 23. A paper feed timing roller 25 is provided. A peeling claw 26 is arranged on the left side of the pressure point P2 of the upper and lower rollers 1.2, and further downstream of the peeling claw 26 is a conveyor belt 27. of the receiver sheet 5. Heat roller 28. Paper ejection roller 29. A paper discharge tray 30 is provided. A winding shaft 31 for the donor sheet 4 is provided on the left side of the roll 21, and winds up the used donor sheet 4.

A document mounting table 32 is arranged at the upper part of the image forming apparatus main body 20, and an optical device 33 is provided below it. The optical device 33 includes a light source 40.41 and four reflecting mirrors 42 to 41.
45 and a lens 46, the light sources 40, 41 and the reflecting mirror 42 together constitute a scanner, which scans an original 47 placed on the original table 32. An exposure point Pl is set on the upper roller 1, and the light reflected by the fourth reflection mirror 45 of the optical device 33 reaches this exposure point P1 and forms an image.

Note that the donor sheet 4 is a light-receiving sheet coated with microcapsules encapsulating a colorless dye and a photocuring agent, and the receiver sheet is an image-receiving sheet coated with a developing material. When image-forming exposure is performed on this light-receiving sheet at the exposure point (Pl), the microcapsules in the exposed areas harden.
Overall, a selectively hardened image is formed. When this selectively cured image-formed photoreceptor sheet is overlaid with an image-receiver sheet coated with a developing material and pressurized at pressure point P2, the uncured microcapsules are destroyed and encapsulated inside. Colorless dye flows out.

Then, the colorless dye reacts with the developing material on the image-receiving sheet to develop color. That is, development and transfer are performed at the same time in the pressure point P2. An image forming method using such a light-receiving sheet and an image-receiving sheet to form a colored image on the image-receiving sheet is disclosed in Japanese Patent Laid-Open No. 58-8
The details are shown in Japanese Patent No. 8739.

(g) Effects of the Invention As described above, according to the present invention, since the donor sheet can be fed from a roll and the receiver sheet can be formed into a cart sheet shape, the operability of the image forming apparatus can be improved. Immediately after the rear end of the receiver sheet comes off the upper and lower rollers, the gap forming member prevents the upper and lower rollers from coming into sudden pressure contact, which has the advantage of reducing impact noise. In addition, when the receiver sheet is not interposed between the upper and lower rollers, no pressure is applied to the donor sheet, so the donor sheet does not wrinkle or wrinkle, and the donor sheet is coated with microcapsules containing a liquid substance. Even if the microcapsules are used, the microcapsules will not be destroyed and the surface of the upper roller will not be contaminated by the liquid substance inside.

[Brief explanation of the drawing]

FIG. 1 shows a pressure transfer device which is an embodiment of the present invention.
FIG. 5A shows a state in which a donor sheet and a receiver sheet are interposed between the upper and lower rollers, and FIG. 2B shows a state in which only the donor sheet is interposed between the upper and lower rollers. Figure 2 shows the structure of a pressure transfer device including a pressure relief device, where (A) shows a state in which the pressure relief device is not operating, and (B) shows a state in which the pressure relief device is in operation. Indicates the condition. FIG. 3 is a schematic diagram of an image forming apparatus using the above pressure transfer device. 1-upper roller (upper pressure roller), 2-lower roller (lower pressure roller), 3-ring (gap forming member), 4-donor sheet, 5-receiver sheet.

Claims (1)

[Claims] (1) In a pressure transfer device in which a donor sheet on which an image has been formed and a receiver sheet that receives an image transfer from the donor sheet are passed in an overlapping manner between a pair of pressure rollers, the donor sheet and the receiver sheet are A pressure transfer device comprising a gap forming member that forms a gap between the pair of pressure rollers that is thinner than the thickness of the donor sheet when stacked and thicker than the thickness of the donor sheet.