JPH05165347A - Pressure transfer device and transfer member - Google Patents

Abstract

PURPOSE:To prevent image staining and the corrosion of a roller surface and to eliminate from being generated need for an extra pressing force by equipping one of a couple of pressure roller with an elastic member on its surface and inhibiting at least both end parts of a photosensitive member from being pressed. CONSTITUTION:This device consists principally of an upper pressure roller 61, an intermediate pressure roller 62, and a lower pressure roller 63; and the lower pressure roller 63 is provided with two bearings 100 and the intermediate pressure roller 62 is loaded at two points. The elastic member 101 which covers the surface of the upper pressure roller 61 is made of polyurethane resin, and 1mm thick and as wide as the transfer member 11. The effect for the absorption of pressure unevenness is larger and larger as the elastic member 101 is softer and softer, but the load needs to be increased for specific-density transfer. The photosensitive member 8 and transfer member 11 are sandwiched between the elastic member 101 and intermediate pressure roller 62 for pressure transfer. Thus, the elastic member is made nearly as wide as the transfer member and then the photosensitive member is not pressed outside the transfer member, so the extra pressing force is eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine or a printer for forming an image using a photosensitive transfer type photosensitive member, and more particularly to a pressure transfer apparatus and a transfer member used therefor.

[0002]

2. Description of the Related Art A wide variety of image forming methods and apparatuses are known, and a conventional example of an image forming apparatus using a photosensitive transfer type heat developing material is, for example, Japanese Patent Laid-Open No. 62-
No. 147461 can be mentioned. According to this publication, main mechanical parts such as an exposure part, a heat developing part, and a pressure transfer part are formed inside one constituent body in the apparatus, and image formation is performed in the following procedure.

First, a roll-shaped photosensitive transfer type heat-developable material is cut into a predetermined length and then imagewise exposed to form a latent image. Next, thermal development is performed with a heating roller. After that, the photosensitive member and the transfer member are superposed on each other and pressure-transferred by the rollers, and the separating member discharges the photosensitive member to the photosensitive material discarding portion and the transfer member to the tray via the fixing device.

Japanese Patent Application Nos. 3-24929 and 3-1628
By providing an elastic member on the pressure roller surface of the pressure transfer device as shown in No. 91, pressure unevenness caused by a shape error of the pressure roller and unevenness of the thickness of the transfer member is eliminated. Can be absorbed, a uniform pressure distribution can be obtained, density unevenness due to pressure unevenness can be eliminated, and an image forming apparatus with high image quality can be formed.

[0005]

However, the above-mentioned prior art has the following problems.

Conventionally, when the pressure roller has no elastic member, the pressing force is applied only to the width of the transfer member, and the surface of the photosensitive member and the lower pressure roller are not in contact with each other outside the transfer member. However, when the pressure roller is provided with an elastic member, when pressure transfer is performed, the elastic member is crushed and deformed due to the applied pressure, and the photosensitive member and the transfer member are embedded in the elastic member, so that they are located outside the transfer member. Will be applied pressure. Therefore, on the outside of the transfer member, the photosensitive member comes into contact with the lower roller and is pressed, and the color material is transferred from the photosensitive member to the lower pressure roller. In this way, the coloring material attached to the lower pressure roller has a drawback that it stains the transfer member and significantly deteriorates the image quality.

Further, since the coloring material contains a chemical substance for thermal development, there is a possibility that the coloring material attached to the lower roller may erode the surface of the roller, thereby deteriorating the durability of the roller.

Further, if a pressure is applied also to the outside of the transfer member, an extra pressure which is not necessary for transferring the color material is required, and there is a drawback that the apparatus becomes large and the cost becomes high. The present invention solves the above problems in view of such a situation, and an object thereof is to prevent pressurization at both ends of a photosensitive member, thereby preventing image stains and roller surface erosion. The object of the present invention is to provide a small-sized, low-priced, high-quality image transfer device and transfer member that does not require extra pressure.

[0009]

The pressure transfer device of the present invention is a pressure transfer device in which a photosensitive member of a photosensitive transfer type and a transfer member are superposed and pressed by a pair of pressure rollers. Has an elastic member on the surface,
A transfer member used in a pressure transfer device in which at least both ends of the photosensitive member are not pressed, and one of which is pressed by a pair of pressure rollers having elastic members on the surface, The thickness of the elastic member is thicker than the amount of the elastic member crushed by the pressure.

[0010]

EXAMPLES The pressure transfer device and transfer member of the present invention will be described in detail with reference to the following examples.

FIG. 1 is a side sectional view showing an embodiment of a copying machine to which the pressure transfer device of the present invention is applied. First, the operation of the copying machine will be described.

A document 2 is placed on a document table 1 movably provided in the direction of arrow A in the figure, and light rays emitted from a red lamp 3, a green lamp 4 and a blue lamp 5 which are light sources are emitted from the document 2. And the reflected light from the original 2 is imaged on the photosensitive member 8 that moves on the exposure table 7 through the lens 6 to form a so-called scan exposure system.

A continuous sheet-like photosensitive member 8 delivered from a cartridge 20 containing an unexposed photosensitive member 8.
After being exposed on the exposure table 7 to form a latent image, it is heat-developed by the heat developing device 40 via the carrying roller 9. on the other hand,
The cut sheet-shaped transfer member 11 housed in the paper feed tray 10 is sent out by the paper feed device 12, and is superposed on the photosensitive member 8 in synchronization with the image area formed on the photosensitive member 8 so that the roller pressing system is used. Pressure transfer is performed by the pressure transfer device 60. The pressure unit of the pressure transfer device 60 includes an upper pressure roller 61,
It is composed of three rollers, an intermediate pressure roller 62 and a lower pressure roller 63, and includes an upper pressure roller 61 and an intermediate pressure roller 6.
Pressure transfer is performed between the two.

After that, the transfer member 11 is separated from the photosensitive member 8 by the separation roller 64 and is discharged to the paper discharge tray 14 through the conveying roller 13. The photosensitive member 8 is pinched to promote the conveyance and separation of the photosensitive member 8. It is wound around the winding shaft 21 via the roller 65.

Reference numeral 15 is a manual paper feed port, and 16 is a gas filter for removing gas generated in the machine.

Next, details of the pressure transfer device and the transfer member, which characterize the present invention, will be described. The present invention can be divided into two types, (1) the characteristic of the structure of the pressure transfer device and (2) the characteristic of the structure of the transfer member. First, regarding the structure of the pressure transfer, the pressure transfer of FIG. This will be described with reference to a front sectional view of the device.

The pressure transfer device 60 is mainly composed of the upper pressure roller 6
1, a middle pressure roller 62 and a lower pressure roller 63. The lower pressure roller 63 is provided with two bearings 100, and the middle pressure roller 62 has two bearings at two points.
A load of 00 kgf is applied. The surface of the upper pressure roller 61 is covered with the elastic member 101 with a uniform thickness. The material of the elastic member 101 is a polyurethane resin having a hardness of 55 degrees (durometer D), the thickness is 1 mm, and the width is the same as that of the transfer member 11. A softer elastic member 101 has a larger effect of absorbing pressure unevenness, but it is necessary to increase a load in order to transfer a predetermined density. Photosensitive member 8 and transfer member 1
1 is sandwiched between the elastic member 101 and the intermediate pressure roller 62 and transferred under pressure. For the sake of explanation, the elastic member 10 is shown in the drawing.
The thicknesses of the photosensitive member 8, the photosensitive member 8 and the transfer member 11 are exaggerated, and the same applies to FIGS. 3 and 4 described below. .

Even if the elastic member is provided in this manner, the elastic member 1
By setting the width of 01 to be approximately the same as that of the transfer member 11, it is possible to provide a structure in which the photosensitive member 8 outside the transfer member 11 is not pressed, and the transfer of the color material from the photosensitive member 8 to the intermediate pressure roller 62 is performed. It is possible to prevent the transfer member 11 from being soiled and prevent the medium pressure roller 62 from being corroded by the coloring material, thereby eliminating an excessive pressing force.

FIG. 3 is a front sectional view of a pressure transfer device showing a second embodiment of the present invention.

The surface of the upper pressure roller 61 has an elastic member 101.
Covers with a uniform thickness. The material of the elastic member 101 is a polyurethane resin having a hardness of 55 degrees (durometer D) and a thickness of 1 mm. The photosensitive member 8 and the transfer member 11 are sandwiched between the elastic member 101 and the intermediate pressure roller 62 and transferred under pressure. Both ends of the intermediate pressure roller 62 are smaller in diameter than the central portion and have a stepped structure.

With such a structure of the intermediate pressure roller 62, even if the transfer member 11 is embedded in the elastic member 101, the steps on both ends of the intermediate pressure roller 62 are outside the transfer member 11 because of the photosensitive member. 8 can be avoided and pressure on the photosensitive member 8 can be prevented. Further, in this embodiment, it is possible to prevent the pressurization to both ends of the photosensitive member 8 with a relatively simple structure in which only the steps are provided at both ends of the intermediate pressure roller 62.

Next, an embodiment having a characteristic structure of the transfer member will be described.

FIG. 4 is a front sectional view of a transfer member and a pressure transfer device to which the transfer member is applied according to a third embodiment of the present invention.

The transfer member 11 is a coated paper in which a chemical for improving the absorption of the coloring material is applied to the base paper in a thickness of about 30 μm. Normally, a high-quality paper having a thickness of about 0.1 mm is used as the base paper, but in the present embodiment, the high-quality paper having a thickness of 0.4 mm is used as the base paper. The upper pressure roller is covered with the elastic member 101 with a uniform thickness. Elastic member 10
The material of No. 1 is a polyurethane resin having a hardness of 55 degrees (durometer D) and has a thickness of 1 mm. Photosensitive member 8 and transfer member 1
1 is sandwiched between the elastic member 101 and the intermediate pressure roller 62 and transferred under pressure.

The pressure for pressure transfer is usually about 2 to 3 kgf per 1 mm 2 in terms of surface pressure, but the elastic member 101 is crushed by about 0.3 mm when subjected to such high stress. Therefore, when the transfer member 11 has a thickness of about 0.1 mm, the photosensitive member 8 and the intermediate pressure roller 62 come into contact with each other outside the transfer member 11 and are pressed, but in the present embodiment, the transfer member 11 is pressed. By making the thickness of the photosensitive member 8 thicker than the crushed amount of the elastic member 101, it is possible to prevent pressure from being applied to the photosensitive member 8 outside the transfer member 11. Further, with such a structure, similar effects can be obtained even when the transfer members 11 having different sizes are used.

Further, the thickness of the transfer member 11 is set to a normal value of 0.1.
Even when the thickness is set to mm, by using a resin having a hardness of 70 (durometer D) or more for the elastic member 101, the effect of absorbing pressure unevenness is reduced, but even if the surface pressure required for pressure transfer is applied to the elastic member 101. The crush amount can be set to less than 0.1 mm, and pressure on the photosensitive member 8 outside the transfer member 11 can be prevented.

In the present embodiment, an image forming apparatus using a heat-developable photosensitive member has been described as an example, but the present invention is not limited to this, and generally, the selective curability of microcapsules is used to apply the image forming apparatus. Needless to say, the present invention can be applied to general image forming apparatuses that form images by pressure.

Further, in the present embodiment, a copying machine has been described as an example, but the present invention is not limited to this, and it is needless to say that the present invention can be applied to all image forming apparatuses such as printers, facsimiles and electronic cameras. Absent.

[0029]

As described above, according to the pressure transfer device of the image forming apparatus of the present invention, in the pressure transfer device using the photosensitive member of the photosensitive transfer type, one of the pressure rollers is elastic on the surface. A transfer member used in a pressure transfer device that has a member and is structured such that at least both ends of the photosensitive member are not pressed, or one of them is pressed by a pair of pressure rollers having an elastic member. By making the thickness of the elastic member thicker than the amount of the elastic member crushed by pressure, pressure at both ends of the photosensitive member is prevented, and there is no image stain or erosion of the roller surface. It is possible to provide a pressure transfer device and a transfer member that are small in size, low in cost, and have high image quality, which do not require the above.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of the present invention.

FIG. 2 is a front sectional view of a pressure transfer device showing a first embodiment of the present invention.

FIG. 3 is a front sectional view of a pressure transfer device showing a second embodiment of the present invention.

FIG. 4 is a front sectional view of a pressure transfer device showing a third embodiment of the present invention.

[Explanation of symbols]

 1 Original Plate 2 Original 3 Red Lamp 4 Green Lamp 5 Blue Lamp 6 Lens 7 Exposure Plate 8 Photosensitive Member 9, 13 Conveying Roller 10 Paper Tray 11 Transfer Member 12 Paper Feeding Device 14 Paper Ejection Tray 15 Manual Paper Feeding Port 16 Gas Filter 20 Cartridge 21 Winding Shaft 40 Thermal Development Device 60 Pressure Transfer Device 61 Upper Pressure Roller 62 Middle Pressure Roller 63 Lower Pressure Roller 64 Separation Roller 65 Pinch Roller 100 Bearing 101 Elastic Member

Claims (2)

[Claims] 1. A pressure transfer device in which a photosensitive member having a microcapsule in which at least a photosensitive material and a coloring material are encapsulated on a support and a transfer member are overlapped and pressed by a pair of pressure rollers. Any one of the above has a structure in which an elastic member is provided on the surface and at least both ends of the photosensitive member are not pressed. 2. A microcapsule in which at least a photosensitive material and a coloring material are encapsulated is laminated with a photosensitive member on a support, and one of them is applied by a pair of pressure rollers having an elastic member on the surface. What is claimed is: 1. A transfer member used in a pressure transfer device, wherein the thickness of the transfer member is thicker than the amount of collapse of the elastic member due to pressure.