JPH05150436A - Image forming device - Google Patents

Abstract

PURPOSE:To eliminate the wrinkles of a photosensitive member caused in a heat developing device and to prevent image quality from being deteriorated by the unevenness of density caused by the wrinkles. CONSTITUTION:A tension roller which rotates in an outside direction so that tension in the outside direction may be given to both ends of a photosensitive member 8, or a frictional disk which holds a film by the parts of two disks so as to guide to the outside, or tension rollers 302, 303, 304 and 305 which are arranged to be inclined to the outside and nip the photosensitive member 8 are provided on or around the heating cylinder 41 of the heat developing device 40.

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 for forming an image on a copying machine, a printer or the like using a heat developing material.

[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 heat developing material is, for example, a photosensitive transfer type heat developing material. No. 62-147461 can be mentioned. According to this publication, the exposure unit, the thermal development unit,
A main mechanism portion such as a pressure transfer portion is formed inside one constituent body, and image formation is performed by 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 image receiving paper are superposed and pressure-transferred by the roller, and the photosensitive member is transferred to the photosensitive material discarding section by the separating device.
The image receiving paper is discharged to the tray via the fixing device.

[0004]

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

The photosensitive member often uses a resin film such as polyethylene terephthalate or paper as a base material, and greatly expands when heated. As a result, wrinkles are gradually generated from the contact area with the heating surface, and the portion that has become wrinkles and floats is insufficiently heated, resulting in uneven development, causing unevenness in image density and paper wrinkles in pressure transfer. , The image quality was remarkably deteriorated.

The present invention has been made in view of the above circumstances and solves the above problems. An object of the present invention is to perform thermal development of an image forming apparatus capable of obtaining a high quality image by uniformly heating a photosensitive member. To provide a device.

[0007]

The heat developing apparatus of the present invention comprises:
It is characterized in that it has means for applying tension in a direction perpendicular to the traveling direction of the photosensitive member.

[0008]

EXAMPLES The heat developing apparatus of the present invention and the image forming apparatus using the same will be described in detail below with reference to Examples.

FIG. 1 is a front sectional view of a copying machine using a heat developing apparatus according to an embodiment of the present invention. First, the operation of this 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-shaped 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 conveying roller 9 and the tension applying means 100. 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 to press the roller. The pressure is transferred by the pressure transfer device 60 of the method. The pressure unit of the pressure transfer device 60 is composed of three rollers, an upper roller 61, a middle roller 62, and a lower roller 63.
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, an embodiment of the heating portion of the heat developing apparatus of the present invention will be described.

FIG. 2 is a thermal developing device 4 of the image forming apparatus of FIG.
It is the perspective view which showed 0. The photosensitive member 8 is wound around a heating cylinder 41 having a heating peripheral surface by a predetermined amount, and while being conveyed while being given a tension, is contact-heated from the surface on which the microcapsules are not applied. Both ends of the heating cylinder 41 are rotatably supported by bearings 42 attached to a frame (not shown). Further, the heating cylinder 41 has a halogen lamp heater 43 inside the cylinder, and the heating amount is appropriately controlled so that the heating peripheral surface becomes constant at a predetermined temperature between about 120 ° C and 160 ° C. ing.

The photosensitive member 8 of the present invention comprises a support made of a PET (polyethylene terephthalate) film and a photosensitive silver halide, a reducing agent and a polymerizable compound disclosed in the above-mentioned JP-A-62-147461. And the microcapsule in which the coloring material is enclosed is applied. The coefficient of thermal expansion of the above-mentioned PET material is approximately 0.005% to 0.0
Although it is 2% / ° C, it can be adjusted by a residual strain generated in the film manufacturing process and an annealing treatment for removing it. The photosensitive member 8 is the heating cylinder 4
1 expands according to the temperature heated above and the coefficient of thermal expansion.

Next, an embodiment of the tension applying means of the heat developing apparatus which is a feature of the present invention will be described.

FIG. 3 is an exploded perspective view of the tension applying means 100. FIG. 3 shows the upper unit 110 centered on the guide roller 101 and the tension roller 10 for the sake of explanation.
The lower unit 120 centering around 2, 102 is shown separately. The guide roller 101 is rotatably supported by a bearing 103 fixed to a frame (not shown). The photosensitive member 8 is slightly wound around and guided by the guide roller 101. Guide roller 1
01 is driven as the photosensitive member 8 is conveyed. The tension rollers 102, 102 are rotatably supported by the lower frame 104, and are rotated by being driven in the directions of arrows A and A ′ in the figure by a motor 107 via gears 105, 106. A friction member 108 made of felt is provided on the circumferential surfaces of the tension rollers 102, 102. The lower unit is rotatably mounted in the main body of the device (not shown) via a shaft 109, and the spring 1
The tension roller 102 is urged upward by 11, 111 so as to come into pressure contact with the guide roller 101 at the position indicated by the alternate long and short dash line in the figure. By the pressure contact force of the spring 111 and the friction coefficient of the friction member 108, an arrow F,
The tension perpendicular to the transport direction indicated by F'is set.

According to the experiments conducted by the present inventor, when the tensions F and F'have a magnitude of 200 gr or more, wrinkles do not occur during heat development and a good image is obtained. At this time, the friction coefficient between the back surface of the photosensitive member 8 and the friction member 108 was 0.2, and the pressure contact force of the spring 111 was 1 kg. If the number of revolutions of the tension roller was in the range of 10 rpm to 3000 rpm, there was no significant difference in the effect of preventing the generation of wrinkles.

Next, a second embodiment of the tension applying means of the heat developing apparatus of the present invention will be described with reference to FIGS. FIG. 4 is a top view of the tension applying means 200 of this embodiment, and FIG. 5 is a cross-sectional view taken along the line AA 'and BB' in FIG. As shown in FIG. 5, the friction discs 201, 201 made of hard rubber are rotated so that a part of both discs presses the side end portions of the photosensitive member 8 from both sides to a bent rotation shaft 202 fixed to a device body (not shown). A pair of friction disks 201, 201, which are movably mounted, are arranged on both sides of the photosensitive member 8 which is conveyed in the direction of arrow C in the figure as shown in FIG. In a portion where the friction disk 201 shown by the diagonal lines in FIG. 4 presses the photosensitive member 8,
Since the peripheral speed direction of the friction disk has a component for pulling the photosensitive member 8 outward as indicated by arrows D and D ′ in FIG. 4, it is possible to apply tension in a direction perpendicular to the transport direction.

According to experiments conducted by the present inventor, in the present embodiment, the diameter of the friction disk is 10 mm to 100 mm,
The bending angle α of the rotating shaft 202 is 5 degrees to 45 degrees, and the photosensitive member 8
It was recognized that the effect of preventing the development of wrinkles due to heat development was obtained when the angle β in the peripheral speed direction at the pressure contact portion with was in the range of 30 to 70 degrees.

Next, a third embodiment of the tension applying means of the heat developing apparatus of the present invention will be described with reference to FIGS. FIG. 6 is a perspective view of the tension applying means 300 of this embodiment. The guide roller 301 is rotatably supported by a bearing 309 fixed to a frame (not shown). Photosensitive member 8
Is slightly wound around the guide roller 301 and guided. The guide roller 301 is driven as the photosensitive member 8 is conveyed. The four rubber tension rollers 302, 303, 304 and 305 are rotatably supported by the lower frame 306. The lower frame 306 is rotatably attached to the main body of the device (not shown) via a shaft 307, and includes springs 308, 3 and 3.
08, tension rollers 302, 303, 30
4, 305 are urged upward so as to come into pressure contact with the guide roller 301. FIG. 7 shows the tension roller 302,
FIG. 6 is a view showing angles at which 303, 304, and 305 are arranged, and is seen from above in FIG. 6 except for the guide roller 301 and the photosensitive member 8. As shown in FIG. 7, since the tension rollers 302, 303, 304 and 305 are arranged so as to spread from the upstream side to the downstream side in the conveying direction of the photosensitive member 8, the tension rollers 302, 303, and 303 are arranged as the photosensitive member 8 is conveyed. When the 304 and 305 are driven and rotated, a force in a direction pulling the photosensitive member 8 to the outside is generated, and a tension in a direction perpendicular to the conveying direction can be applied.

According to experiments conducted by the present inventor, the opening angles α of the outer tension rollers 302 and 305 are in the range of 5 to 30 degrees, and the opening angles β of the inner tension rollers 303 and 304 are in the range of 2 to 20 degrees. It was also found that setting α such that α is larger than β is effective in preventing the occurrence of heat development wrinkles.

Next, a fourth embodiment of the tension applying means of the heat developing apparatus of the present invention will be described with reference to the perspective view of FIG. In this embodiment, the upper unit of the embodiment shown in FIG. 3 also serves as the heating portion of the heat developing device. Similar to the heat developing device shown in FIG. 2 described above, the photosensitive member 8 is wound around a heating cylinder 401 having a heating peripheral surface by a predetermined amount and is conveyed while being given a tension. A feature of this embodiment is that the surface coated with the microcapsules is heated by contact in order to prevent damage to the capsule application surface from the tension roller 102 of the lower unit 120, which is the tension applying means. Both ends of the heating cylinder 401 are rotatably supported by bearings 402 attached to a frame (not shown). The heating cylinder 401 has a halogen lamp heater 403 inside the cylinder, and the heating peripheral surface is about 120 ° C.
The heating amount is appropriately controlled so as to be constant at a predetermined temperature between 160 ° C. Heating cylinder 401 of photosensitive member 8
The wrap angle is provided by wrap rollers 406 and 407 rotatably mounted on a frame (not shown). The detailed configuration of the lower unit 120 is shown in FIG.
The embodiment shown in FIG.

Also in this embodiment, the effect of preventing the development of wrinkles due to heat development was similar to that of the embodiment shown in FIG. 3 described above, but when the pressure contact force of the tension roller was increased, the tension roller was pressed against the image. The damage was considered to be caused by. However, the present embodiment has an effect that the device can be configured more compactly and inexpensively within the range of the appropriate pressure contact force of the tension roller.

The tension applying means which is a feature of the present invention has been described with reference to some embodiments. However, in any mechanism, the tension applying means is provided in the vicinity of the heating portion of the heat developing device in a direction perpendicular to the conveying direction of the photosensitive member. The effect intended by the present invention can be exerted as long as the above-mentioned tension is applied, and therefore the present invention is not limited to the mechanical configuration of the above-described embodiment.

Further, in all of the above-mentioned embodiments, the heating cylinder is rotated along with the static friction force by the conveying force of the photosensitive member 8, but the heating cylinder is stationary and the photosensitive member slides on the heating surface. However, it has been confirmed that the same effect can be obtained with a configuration in which heating is performed. In that case, it is not always necessary to have a completely cylindrical shape, and a heat developing apparatus having a heating surface using a part of an arc may be used.

Further, the present invention can be widely applied to all photothermographic materials and is not limited to the photoconductive transfer type photothermographic material described in this embodiment.

In the present embodiment, the 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.

[0030]

As described above, according to the image forming apparatus of the present invention, in the image forming apparatus using the photosensitive transfer type heat developing material, the image forming apparatus is provided in the vicinity of the heat developing apparatus in the direction perpendicular to the traveling direction of the photosensitive member. By providing the means for applying tension, there is an effect that a wrinkle of the photosensitive member is not generated in the heating portion of the thermal developing device, so that a high quality image having no density unevenness can be obtained with a simple structure.

[Brief description of drawings]

FIG. 1 is a front sectional view showing an image forming apparatus using the present invention.

FIG. 2 is a perspective view showing an embodiment of the heat developing apparatus of the present invention.

FIG. 3 is an exploded perspective view showing a first embodiment of the tension applying means of the heat developing apparatus of the present invention.

FIG. 4 is an elevational view showing a second embodiment of the tension applying means of the heat developing apparatus of the present invention.

5 is a cross-sectional view of cross sections AA 'and BB' in FIG.

FIG. 6 is a perspective view showing a third embodiment of the tension applying means of the heat developing apparatus of the present invention.

FIG. 7 is a diagram showing a roller arrangement of a third embodiment of the tension applying means of the heat developing apparatus of the present invention.

FIG. 8 is a perspective view showing a fourth embodiment of the tension applying means of the heat developing apparatus 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 Ejecting Tray 15 Manual Paper Feeding Port 16 Gas Filter 20 Cartridge 21 Winding Shaft 40 Thermal Development Device 41, 401 Heating Cylinder 42, 402 Bearing 43, 403 Halogen Lamp Heater 60 Pressure Transfer Device 61 Upper Roller 62 Middle Roller 63 Lower Roller 64 Separation Roller 65 Pinch Roller 101, 301 Guide Roller 102 , 302, 303, 304, 305 Tension roller 110 Upper unit 120 Lower unit 201 Friction disk 202 Rotating shaft 406, 407 Winding roller

Claims (1)

[Claims] 1. An image forming apparatus using a heat-developable photosensitive member, comprising at least an exposure device for exposing the photosensitive member and a heat developing device for heating the photosensitive member,
An image forming apparatus comprising a means for applying a tension in a direction perpendicular to a traveling direction of a photosensitive member near the heat developing device.