JP2955694B2 - Thermal developing apparatus and image forming apparatus having the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat developing apparatus for an image forming apparatus for forming an image using a heat developing material, such as a copying machine or a printer.

[0002]

2. Description of the Related Art A wide variety of image forming methods and apparatuses are known. As a conventional example of an image forming apparatus using a heat developing material, for example, a photosensitive transfer type heat developing material is disclosed in No. 62-147461. According to this publication, an exposure unit, a heat development unit,
A main mechanism such as a pressure transfer unit is formed inside one component, and image formation is performed in the following procedure.

[0003] First, after a roll-shaped photosensitive transfer type heat developing material is cut to a predetermined length, image exposure is performed to form a latent image. Next, thermal development is performed by a heating roller. Thereafter, the photosensitive member and the image receiving paper are superimposed and pressure-transferred by a roller.
The image receiving paper is discharged to a tray via a fixing device.

[0004] The heating surface of the heating roller for performing the thermal development is a smooth cylindrical curved surface, and is a straight line without unevenness when viewed in a cross section in the paper width direction. The photosensitive member is heated by rotating the cylinder on a cylindrical heating surface, or by fixing the cylinder and sliding the photosensitive member while contacting the back surface of the photosensitive member.

[0005]

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

[0006] The photosensitive member is often made of a resin film such as polyethylene terephthalate or paper as a base material, and greatly expands when heated. As a result, wrinkles gradually occur from the contact area with the heated surface, and the wrinkled and floating parts are insufficiently heated, causing uneven development, causing uneven image density and paper wrinkles due to pressure transfer. Image quality was significantly degraded.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to solve the above-described problems. It is an object of the present invention to provide an image forming apparatus capable of obtaining a high-quality image by uniformly heating a photosensitive member. It is to provide a device.

[0008]

Means for Solving the Problems The heat developing apparatus of the present invention comprises:
Heat development is performed by heating the exposed photosensitive member while transporting the photosensitive member, and the photosensitive member is wound around a heating unit, and is contact-heated only from one surface side while being tensioned. On the contact surface of the heating unit, a plurality of fine irregularities are formed in a direction perpendicular to the direction of conveyance of the photosensitive member, and by using tension, wrinkles due to thermal expansion of the photosensitive member are formed along the minute irregularities. It is characterized by absorption. In this case, it is desirable that the length of the curve along the minute unevenness of the heating section is slightly longer than the width in consideration of the thermal expansion of the photosensitive member.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The thermal developing apparatus of the present invention and an image forming apparatus using the same will be described in detail below with reference to embodiments.

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 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 emitted from a red lamp 3, a green lamp 4, and a blue lamp 5, which are light sources, is applied to the document 2. , And the reflected light from the original 2 forms an image on a photosensitive member 8 that moves on an exposure table 7 through a lens 6 to form a so-called scan exposure system.

A continuous sheet-like photosensitive member 8 sent out from a cartridge 20 containing an unexposed photosensitive member 8
Is exposed on an exposure table 7 to form a latent image, and is heated and developed by a heat developing device 40 via a transport roller 9. on the other hand,
The transfer member 11 in the form of a cut sheet stored in the paper feed tray 10 is sent out by the paper feed device 12 and is superimposed on the photosensitive member 8 in synchronization with an image area formed on the photosensitive member 8 so that a roller pressing system is used. Pressure transfer is performed by the pressure transfer device 60. The pressing portion of the pressure transfer device 60 includes three rollers, an upper roller 61, a middle roller 62, and a lower roller 63, and the pressure transfer is performed between the upper roller 61 and the middle roller 62.

Thereafter, the transfer member 11 is separated from the photosensitive member 8 by a separation roller 64, and is discharged to the paper discharge tray 14 through the transfer roller 13. The photosensitive member 8 is pinched to transfer the photosensitive member 8 and to promote separation thereof. It is wound on the winding shaft 21 via the roller 65.

Reference numeral 15 denotes a manual paper feed port, and reference numeral 16 denotes a gas filter for removing gas generated inside the apparatus.

Next, an embodiment of the heat developing apparatus of the present invention will be described.

FIG. 2 shows a thermal developing device 4 of the image forming apparatus shown in FIG.
FIG. The photosensitive member 8 is wound around a heating cylinder 41 having a heating peripheral surface by a predetermined amount, and while being transported under 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). The heating cylinder 41 has a halogen lamp heater 43 inside the cylinder, and the heating amount is appropriately controlled such that the heating peripheral surface is kept at a predetermined temperature between about 120 ° C. to 160 ° C. ing.

FIG. 3 is a sectional view of the heating cylinder 41. The cylindrical surface is periodically provided with arc-shaped irregularities having a pitch P = 20 mm and an amplitude a = 0.2 mm. Regarding the method of forming the unevenness, it is preferable that the unevenness is such that the length of the curve along the unevenness on the cross section in the cylindrical axis direction shown in FIG. 3 is slightly longer than the width of the photosensitive member after the thermal expansion. If the length of the curve along the irregularities is equal to or shorter than the width of the photosensitive member after thermal expansion, wrinkles of the photosensitive member 8 during heating often occur. If the length is too long, the photosensitive member 8 in the concave portion floats, resulting in poor heating. Has been experimentally confirmed.

The photosensitive member 8 of the present invention is formed on a support made of a PET (polyethylene terephthalate) film on a photosensitive silver halide, a reducing agent and a polymerizable compound disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 62-147461. And a microcapsule in which a coloring material is sealed. The coefficient of thermal expansion of the above-mentioned PET material is approximately 0.005% to 0.05%.
Although it is 2% / ゜ C, it can be adjusted by the residual strain generated in the film manufacturing process and the annealing treatment for removing the residual strain.

FIGS. 4A and 4B are perspective views showing how wrinkles occur when heat development is performed using the heat developing apparatus 40 of this embodiment and the smooth heating cylinder 141 described in the conventional example. . In the conventional example, wrinkles are generated on the heating cylinder 141, whereas in the heat developing device 40 (FIG. 4A) of the present invention, the photosensitive member 8 other than the heating cylinder 41 is wavy. That is, the excess length of the photosensitive member 8 extending laterally is eliminated by wrinkling, but is eliminated by following the irregularities, and the extra length is given by the irregularities. A force for pulling the photosensitive member 8 inward from the unheated portion is applied to stably suppress wrinkles.

Next, another embodiment of the heat developing apparatus of the present invention will be described with reference to a sectional view of a heating cylinder 241 shown in FIG. The configuration is the same as the above-described conventional example except that the shape of the unevenness on the heating cylinder 241 is different. In the heating cylinder 241 of the present embodiment, a portion where the image area of the photosensitive member 8 contacts the heating cylinder 241 is smooth, and projections are provided on both ends of the periphery outside the image area. In the above-described embodiment, wrinkles due to unevenness may occur depending on the state of tension and the like due to unevenness in the image portion, but in the present embodiment, since the heating cylinder in the image area is smooth, the image due to the occurrence of fine wrinkles There is no quality deterioration.

[0021]

Further, in the embodiment shown in FIG. 3, distortion may occur due to a change in the path length of the photosensitive member 8 in the transport direction between the concave portion and the convex portion, which may appear as density unevenness. The unevenness can be avoided by providing a spiral.

In all of the above-described embodiments, the heating cylinder is rotated by receiving the static friction force due to the conveying force of the photosensitive member 8, but the heating cylinder is stationary and the photosensitive member slides on the heating surface. It has been confirmed that a similar effect can be obtained even with a configuration in which heating is performed. In that case, the entire cylindrical shape is not necessarily required, and a heat developing device having a heating surface using a part of an arc may be used.

The present invention can be applied to a wide range of photothermographic materials in general, and is not limited to the photothermographic materials of the photosensitive transfer type described in the present embodiment.

In this embodiment, a copying machine has been described as an example. However, the present invention is not limited to this, and it goes without saying that the present invention can be applied to all image forming apparatuses such as printers, facsimile machines, and electronic cameras. Absent.

[0026]

As described above, according to the image forming apparatus of the present invention, in an image forming apparatus using a photosensitive transfer type heat developing material, the heat developing device has unevenness in a direction perpendicular to the traveling direction of the photosensitive member. Alternatively, by having a curved heating surface, there is an effect that a high-quality image with no density unevenness can be obtained with a simple configuration because there is no wrinkling of the heated photosensitive member.

[Brief description of the drawings]

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

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

FIG. 3 is a cross-sectional view showing one embodiment of the heat developing device of the present invention.

FIG. 4 is a perspective view showing the effect of the present invention.

FIG. 5 is a sectional view showing another embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Document table 2 Document 3 Red lamp 4 Green lamp 5 Blue lamp 6 Lens 7 Exposure table 8 Photosensitive member 9, 13 Conveyance roller 10 Paper feed tray 11 Transfer member 12 Paper feeder 14 Paper discharge tray 15 Manual paper feed port 16 Gas filter REFERENCE SIGNS LIST 20 cartridge 21 take-up shaft 40 heat developing device 41, 141, 241 heated cylinder 42 bearing 43 halogen lamp heater 60 pressure transfer device 61 upper roller 62 middle roller 63 lower roller 64 separation roller 65 pinch roller

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A 2-58236 (JP, U) JP-A 51-70539 (JP, U) JP-B 57-496 (JP, B2) (58) Field (Int.Cl. ⁶ , DB name) G03D 13/00

Claims (3)

(57) [Claims] 1. A thermal developing apparatus for performing thermal development by heating an exposed photosensitive member while transporting the photosensitive member, wherein the photosensitive member is wound around a heating unit that heats the photosensitive member, and is provided with tension. At the same time contact heating is performed from only one surface side, and a plurality of minute irregularities are formed on the contact surface of the heating unit in a direction perpendicular to the conveying direction of the photosensitive member. A thermal developing device for absorbing wrinkles caused by thermal expansion of the photosensitive member along the fine irregularities. 2. A method for applying a force to pull the photosensitive member to the inside of a heating area, and adjusting the length of a curve along the minute unevenness of the heating unit to such an extent that the photosensitive member does not float. 2. The heat developing apparatus according to claim 1, wherein the width is slightly longer than a width in consideration of expansion. 3. An image forming apparatus comprising the heat developing device according to claim 1.