JP2589372B2 - Pressure developing device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION (a) Industrial Field of the Invention The present invention relates to an improvement of a pressure / pressure release mechanism in a pressure developing device that performs development by pressing.

(B) Prior Art A method of releasing pressure using an eccentric cam in a pressure developing device having a pressure roller pressed at high pressure is disclosed in JP-A-63-92954. That is, pressurization / pressure release is performed by rotating the eccentric cam. By releasing the pressure, the jam in the pressure roller portion and the maintenance operation can be easily performed, and by releasing the pressure when the paper is jammed, rapid torque fluctuation can be prevented.

(C) Problems to be Solved by the Invention However, the eccentric cam may rotate when stopped in an unstable state. It is very dangerous if the eccentric cam rotates and the pressure release state cannot be maintained when the pressure is released to perform jam release, maintenance, or the like.

SUMMARY OF THE INVENTION It is an object of the present invention to improve safety by allowing a stopped state to be maintained even when an eccentric cam is in an unstable state.

(D) Means for Solving the Problems The present invention relates to a pressure developing device for pressurizing / releasing a pair of pressure rollers using a spring and an eccentric cam. A driving force transmission device for transmitting rotation to the eccentric cam,
The driving force transmission device includes a one-way clutch that constantly restricts rotation of the eccentric cam in a direction opposite to a rotation direction of the driving device.

(E) Function In the present invention, the driving force transmission device is provided with the one-way clutch, so that the driving force transmission device and the eccentric cam can rotate only in one direction (positive direction). In other words, the rotational force in the forward direction of the driving device is transmitted to the eccentric cam via the one-way hook, and the eccentric cam can be rotated. However, when an external force in the opposite direction is applied to the eccentric cam, rotation in the opposite direction is prevented by the one-way clutch. FIG. 2 shows a cam curve, for example, a,
The pressure developing device is in a pressurized state at points b and c, and is in a pressure released state at point d. By the one-way clutch, the eccentric cam can rotate to the right in the figure but is prevented from rotating to the left. Therefore,
Even if the cam is stopped at any of the points a to d, the state does not come off. Further, at the time of pressurization, the pressurization is performed by the drive device acting as a brake and operating slowly.

(F) Example FIG. 3 is a diagram showing a configuration of an image forming apparatus provided with a pressure developing device.

An original table 1 made of a transparent hard glass body is provided on the upper surface of the image forming apparatus main body. An original A to be copied is placed on the original table 1 with the original surface facing down. Platen 1
An optical system is provided below. Optical system 2 is light source 2
a, 2b, mirrors 2c to 2f, lens 2g, and filter 2h. The document A on the document table 1 is exposed by light sources 2a and 2b, and the reflected light is guided to an exposure point described later via mirrors 2c to 2f, a lens 2g, and a filter 2h. The filter 2h has a plurality of filters having different transmission wavelengths, and performs color correction of the document reflected light by adjusting the amount of each filter inserted into the optical path. The insertion amount of the filter is determined according to the sensitivity characteristics of the media sheet, the image color desired by the user, and the like.

A slide projector 3 is provided on the right side of the image forming apparatus main body.
Is provided detachably. The slide projector 3 has a light source 3a, a slide holder 3b, and a lens 3c. A slide film to be printed is inserted into the slide holding section 3b. On the other hand, the mirror 2f of the original reflected light optical system is rotatable, and is rotated substantially 90 degrees by rotating a handle (not shown) provided on the front side of the image forming apparatus main body. . When the mirror 2f is rotated (the state shown by the two-dot chain line in the figure), the transmitted light of the slide film inserted into the slide holder 3b is transmitted to the lens 3c.
Through the exposure point. The lens 3c is also provided with a color correction filter.

A mounting portion for a media sheet is provided on the left side in the image forming apparatus main body. The media sheet 4 is made of a light-curable material,
It is coated with microcapsules having a particle size of about 10 to 20 μm enclosing a coloring dye or the like. The microcapsules are hardened by exposure and destroyed by pressure, causing the chromogenic dye to flow out. This media sheet becomes a photosensitive and pressure-sensitive sheet in combination with a receiver sheet described later. The receiver sheet is obtained by applying a thermoplastic resin and a developing material (which develops the coloring dye) onto paper.

The media sheet 4 is wound around a supply shaft 51 and is housed in a storage room R of a media cartridge 5 made of a light shielding material, and is protected from external light and external pressure. The supply shaft 51 can be locked by a ratchet mechanism including a solenoid. The media cartridge 5 also has a take-up shaft 52, and the used media sheet is taken up by the take-up shaft 52. Winding shaft
52 is always urged in the winding direction to prevent the media sheet 4 from becoming loose. Replacement of the used media sheet 4 is performed for the entire cartridge 5.

The replacement of the media cartridge 5 is performed by taking the media cartridge 5 in and out. The bucket 6 is provided on the front side of the main body of the image forming apparatus along the sliders 61 and 61 so as to be able to be pulled out, so that the media cartridge 5 can be inserted from above. A tractor roller 62 is provided at the upper right end of the bucket 6. A pin 62a is provided around the end of the tractor roller 62. On the other hand, in the new media cartridge 5, the leading end of the media sheet 4 is slightly pulled out from the opening 53 of the storage chamber R. This is pulled out by hand and hooked on the tractor roller 62. A leader sheet, which is strongly stiff and slightly wider than the media sheet, is attached to the end of the media sheet, and the holes formed at both ends of the leader sheet are the pins of the tractor roller 62.
Multiplied by 62a. When the leader sheet is hooked on the tractor roller 62 and the bucket 6 is pushed into the image forming apparatus main body, the bucket sensor S1 is turned on, and when the front cover of the image forming apparatus main body is closed, the cover switch S2 is turned on. When both of them are turned on, automatic loading of the media sheet (automatic setting of the media sheet) is performed.

An exposure table 7, a buffer roller 8, and a pressure developing device 9 are provided on the right side of the media sheet mounting portion. The media sheet that has been wound on the tractor roller 62 at the time of the initial setting is wound on the winding shaft 52 via the exposure table 7, the buffer roller 8, and the pressure developing device 9 by automatic loading. The above-mentioned document reflected light or slide transmission hole is guided to the exposure point P1 on the exposure table 7, and exposes the media sheet 4. Then, a latent image (an image in which a partial microcapsule is hardened) corresponding to the document or the slide image is formed on the media sheet 4. Reference numeral 71 denotes a heater that is turned on at the time of exposure, and the media sheet 4 is provided to keep the light sensitivity constant because the light sensitivity changes depending on the temperature.

FIGS. 1A and 1B are views showing the configuration of a pressure developing device. The pressure developing device 9 has upper and lower pressure rollers 91 and 92. Pressure development point P between upper and lower pressure rollers 91 and 92
2 The upper pressure roller 91 is held by the upper holder 93 so as to be movable in the vertical direction. Backup rollers 91a and 91b are rotatably held above the upper pressure roller 91. The lower pressure roller 92 is rotatably held by a lower holder 94. The upper and lower holders 93 and 94 are provided rotatably about a fulcrum shaft 95, and pressurization / pressure release is performed by a spring 96 and an eccentric cam 97. When the upper and lower holders 93 and 94 are pressurized, the upper and lower pressure rollers 91 and 92
Is naturally pressurized (FIG. 1 (A)). At this time, since the upper pressure roller is urged downward by the backup rollers 91a and 91b, a uniform pressure can be obtained in the axial direction. When the pressure of the upper and lower holders 93 and 94 is released, the pressure of the upper and lower pressure rollers 91 and 92 is also released (FIG. 1B). The upper and lower pressure rollers 91 and 92 are pressurized only during pressure development, and are in a pressure released state at other times.

The drive force of a motor (drive device) 99 is transmitted to the eccentric cam 97 by a drive force transmission device 98. The driving force transmission device 98 transmits the driving force of the motor 99 to the eccentric cam 97 by the gears 98a to 98d. The gear 98b is provided with a one-way clutch 98e to prevent the gears 98a to 98d and the eccentric cam 97 from rotating in opposite directions.

This eccentric cam 97 has characteristics as shown in FIG.
Since it can rotate only in one direction, it can be stably stopped at points a to d, for example. One-way clutch
If the stop is performed in such a state without 98e, the eccentric cam rotates in the reverse direction, which is extremely dangerous when the jam is released in the pressure release state d. Further, since the pressure can be applied at different pressure points as shown in a to c, the image density can be adjusted. The higher the pressure, the higher the density of the formed image because the microcapsules are easily broken, and the lower the pressure, the lower the density. Pressure release state d
When returning to the pressurized state a from, the rotation of the motor 99 acts as a brake, so that the pressurizing operation is not sharpened. It should be noted that as the number of gears used in the driving force transmission device is increased, the external force is alleviated and the cam can be stopped stably.

The buffer roller 8 is provided so as to be movable in the directions of arrows B and C in the figure. This movement is performed by a motor (not shown). In this image forming apparatus, the pressure development step is performed after the exposure step is completed. This is because the exposure speed and the pressure development speed are set separately, and the image quality can be improved. The buffer roller 8 is used to change the transport speed of the media sheet.
In the exposure step, exposure is performed while moving the backup roller 8 in the direction of arrow B. Then, the media sheet 4 on which the latent image is formed is stored in the buffer unit at the upper right of the exposure table. When the exposure is completed, the backup roller 8
Moves in the direction of arrow C and sends out the media sheet 4 on which the latent image has been formed to the pressure developing device 9. At this time, the receiver sheet is overlaid on the latent image of the media sheet 4 and pressed together.

A paper cassette 10 is provided on the right side of the image forming apparatus main body. The sheet cassette 10 stores the receiver sheet 11 and is sent out by the sheet feeding device 12. The receiver sheet 11 is temporarily stopped by the timing roller 13 and fed at a timing at which the receiver sheet 11 is superimposed on the latent image on the media sheet. If the leading edge of the latent image on the media sheet 4 and the leading edge of the receiver sheet 11 reach the pressure development point P2, both sheets
4 and 11 are temporarily stopped, and the upper and lower pressure rollers 91 and 92 are pressed. When the pressure is sufficiently applied, the upper and lower compressive rollers 91 and 92 rotate to perform pressure development. At this time, as described above, the buffer roller 8 also moves in the direction of arrow C by the motor. If the media sheet 4 and the receiver sheet 11 are overlaid and pressurized, the uncured microcapsules are broken and the chromogenic dye flows out. The dye develops a color with the developing material and forms an image on the receiver sheet. Thereafter, the two sheets are peeled off, the media sheet 4 is wound around a winding shaft 52, and the receiver sheet 11 is sent to the glossing device 20.

The glossing device 20 heats and presses the receiver sheet 11 so that the resin on the sheet is in a softened state, covers the image surface, and further smoothes it. This gives the image a gloss. In addition, the heating promotes the coloring reaction of the coloring dye. The image formed in this way is discharged to the discharge tray 21 on the left side of the image forming apparatus main body.

(G) Effects of the Invention As described above, according to the present invention, when the pressure roller is in the pressurized state, the reverse rotation of the eccentric cam is always restricted, and the eccentric cam can be stopped in a stable state. For,
Safety during jam clearing processing and maintenance can be ensured. In addition, since the eccentric cam can be reliably stopped while the pressure roller is pressurized with an arbitrary pressure, the pressure of the pressure developing device can be arbitrarily adjusted. Further, at the time of pressurization, the drive device acts as a brake and is slowly pressurized, so that there is no danger, and the device does not shake due to sudden pressurization.

[Brief description of the drawings]

FIGS. 1A and 1B are views showing the structure of a pressure developing device according to an embodiment of the present invention. FIG.
FIG. 6B shows a state at the time of pressure release. FIG. 2 is a cam curve of an eccentric cam used in the apparatus, and FIG. 3 is a schematic configuration diagram of an image forming apparatus provided with the apparatus. 9 Pressure developing device, 91, 92 Pressure roller, 93, 94
Holder, 95: Support shaft, 96: Spring, 97: Eccentric cam, 98a-98d: Gear, 98e: One-way clutch, 99
……motor.

Claims (1)

(57) [Claims] A pressure developing device for pressurizing / releasing a pair of pressure rollers using a spring and an eccentric cam, a driving device for generating one-way rotation, and transmitting the rotation of the driving device to the eccentric cam. And a driving force transmission device, wherein the driving force transmission device has a one-way clutch for always restricting rotation of the eccentric cam in a direction opposite to a rotation direction of the driving device.