JPH0367834A - Picture forming apparatus having pressure developing device - Google Patents

Abstract

PURPOSE:To prevent a light and pressure sensitive sheet from offset due to pressure without a image receiving sheet by providing a means for stopping the start of pressure developing process when a jam sensor detects the jamming of the image receiving sheet. CONSTITUTION:Unless a sensor S2 detects an image receiving sheet within a time taken for said sheet travelling from a PS roller 6 to the sensor S2, any jam is judged to be present, so that the PS roller 6 is stopped and the jam is displayed on an operating panel 27. Thus, the subsequent pressure developing process is not started to prevent an image receiving sheet from offset caused by the jam.

Description

DETAILED DESCRIPTION OF THE INVENTION (Al Industrial Field of Application) This invention relates to a photosensitive pressure-sensitive sheet coated with microcapsules enclosing a photo-curing material 1 and a color-forming dye, and a developing material coated with the color-forming dye. The present invention relates to an image forming apparatus that performs image formation using an image receiving sheet.

fbl Conventional technology In an image forming apparatus that forms images using a photosensitive pressure-sensitive sheet and an image-receiving sheet, when the photosensitive pressure-sensitive sheet is irradiated with imaging light such as reflected light from an original, only the microcapsules in the areas hit by the light are removed. It hardens to form a latent image. When an image-receiving sheet is placed over this latent image area and pressure is applied, the uncured microcapsules are destroyed, and the encapsulated color-forming dye flows out and is colored by the developing material on the image-receiving sheet, forming an image. It looks like this.

Problems to be Solved by the IcI Invention As mentioned above, in the photosensitive pressure sensitive sheet, the uncured microcapsules are destroyed by pressure, and the dye flows out. Therefore, if the image-receiving sheets are not overlapped when the photosensitive pressure-sensitive sheets are fed into the pressure developing device, the dye that flows out will adhere to the pressure developing device, which will stain the next image-receiving sheet. This is a so-called offset phenomenon.

Therefore, it is necessary to prevent only the photosensitive pressure-sensitive sheet from being fed into the pressure developing device and being pressurized.

However, in conventional devices, no countermeasures have been considered in the event that the image receiving sheet gets jammed between the PS roller and the pressure developing device, and due to this jamming of the image receiving sheet, only the photosensitive pressure sensitive sheet is applied. Off-cents may occur due to pressure. Since the PS roller feeds the image receiving sheet instantaneously, it is stopped with the image receiving sheet bent, and since the sheet feeding is unstable when feeding starts, the distance between the PS roller and the pressure developing device is to some extent. Although a distance is provided, a conventional jam sensor has not been provided between this distance, and if the image receiving sheet is jammed during this distance, an offset will occur as described above.

An object of the present invention is to provide a jam sensor immediately before the pressure developing device, and prevent the pressure developing process from being performed when the jam sensor detects a jam in the image receiving sheet.
An object of the present invention is to provide an image forming apparatus that can prevent stains on images.

+d1 Means for Solving the Problem This invention provides an image forming apparatus in which an image receiving sheet temporarily stopped by a PS roller and a photosensitive pressure sensitive sheet on which a latent image has been formed are fed to a pressure developing device and pressurized. The present invention is characterized in that a jam sensor is disposed immediately before the developing device, and means is provided for stopping the start of the pressure developing process when the jam sensor detects a jam in the image receiving sheet 1-.

(e) Function In the pressure developing device of the present invention, when the image receiving sheet jams, the start of the pressure developing process is stopped, so that only the photosensitive pressure sensitive sheet I- is not pressurized. When the image-receiving sheet is momentarily fed by the PS roller, the leading edge of the sheet may bend and cause a jam, but this device reliably detects such jams and performs pressure development only when there is no jam. is started, so offset can be reliably prevented. The means for stopping the start of the pressure development process is (f) Embodiment FIG. 5 is a schematic front view of a copying machine which is an embodiment of the present invention.

A document table 1 is provided on the top surface of the copying machine body, and below it are a light source unit 2a, a mirror unit 2b, a lens 2c,
An optical system having a fixed mirror 2d is provided. The light source unit 2a and the mirror unit 2b are provided so as to be movable back and forth along the document table 1, and when they move forward, they scan the document on the document table and guide the reflected light to an exposure section, which will be described later.

Media cartridge 3 is located on the right side of the center inside the copier body.
is detachably attached to the main body of the copying machine. The media cartridge 3 is provided with a supply shaft 3a9 and a take-up shaft 3b. The supply shaft 3a is housed in a storage chamber R shielded from external light and pressure, and an unused photosensitive pressure sensitive sheet 31 is wrapped around it. One end of the photosensitive pressure sensitive sheet 31 is a storage chamber R.
The film is wound around the winding shaft 3b via the exposure section Pl, the buffer roller 4, the clamping mechanism 8, and the pressure developing device 9. The light reflected from the original is guided to the exposure portion Pl by the above-mentioned optical system, and the photosensitive pressure sensitive sheet 31 is exposed here to form a latent image. The vanofa roller 4 is a row roller capable of reciprocating movement as shown by the arrow in the figure, and moves forward during exposure to once move the photosensitive pressure sensitive sheet on which a latent image has been formed to the upper right side of the exposure area. Note that the clamping mechanism 8 clamps the photosensitive pressure sensitive sheet 31 at this time to prevent the photosensitive pressure sensitive sheet from being pulled out in the opposite direction from the winding shaft 3b. When the exposure is completed, the photosensitive roller 4 moves backward to send the photosensitive pressure sensitive sheet 1- on which the latent image has been formed to the pressure developing device 9. The pressure developing device 9 includes upper and lower pressure rollers 9a and 9b, and a bank up roller 9C that forces the upper pressure roller 9a downward.
It is constructed so that pressure can be released. In this embodiment, when the image-receiving sheet is jammed, the pressure developing device is brought into a pressure release state to stop the start of the pressure developing process.

3(A) and 3(B) are front sectional views of the pressure developing device, with FIG. 3(A) showing the state when pressure is applied and FIG. 3(B) showing the state when the pressure is released. FIG. 4 is an external view of the pressure developing device.

The upper pressure roller 9a and the hasoquano roller 9C are supported by the upper holder 10, and the lower pressure roller 9B is supported by the lower holder 11.
is supported by The upper and lower holders 10.11 are fulcrum shafts 12
It is rotatable by a spring 13 and biased in the pressure contact direction. The upper pressure roller 9a is point-supported so as to be able to move up and down, and is urged downward by the Hanoku roller 9C to come into pressure contact with the roller 9b. By urging the upper pressure roller 9a by the bathoassopro roller 9C, uniform pressing force can be obtained in the axial direction of the upper and lower pressure rollers 9a and 9b.

On the other hand, the pressure on the upper and lower pressure rollers 9a and 9b is released by a cam 14 and an engaging portion 15. When the cam 14 rotates, the cam 1 rotates as shown in FIG. 3(B).
4 presses the engaging portion 15, the upper holder 10 is lifted, and the pressing force of the upper and lower pressure rollers 9a and 9b is released. The pressing force of the pressure roller can also be adjusted by changing the rotation angle of the rotation rim 140). Adjustment of the pressing force is useful in that an image can be formed depending on the size of the image-receiving sheet and the image density state. Driving force from a motor 17 is transmitted to the cam 14 via gears 16a to 16c. The gear 16C is provided with a one-way cruff 16d, which restricts the cam 14 from rotating in only one direction.

That is, this is to prevent the risk of the cam 14 rotating in the opposite direction and being pressurized when the pressure is released. The cam 14 rotates after the pressure development process is completed, and applies pressure to the upper and lower pressure rollers 9a and 9b only during the pressure development process.

In Fig. 5, there is a manual feed tray 5 on the right side of the copying machine main body.
a, paper strength centers 5b and 5c are provided, and an image receiving sheet 5
1 is stored. A PS roller 6 is arranged between the manual feed tray 5a and paper cassettes 5b and 5c.

At the same time as the copying operation starts, an image receiving sheet 51 of an appropriate size is fed from either the manual feed tray 5a or the paper cassettes 5b and 5C. At this time, the PS roller 6 is in a stopped state, and the image receiving sheet is in contact with the PS roller 6 and the leading edge is bent 4.
It will be stopped in the state where it is connected. This image-receiving sheet is then sent to the pressure developing device 9 by the rotation of the PS roller 6. Note that SL and S2 are sensors that detect the image receiving sheet. Sl is composed of an optical sensor and determines not only whether there is an image receiving sheet but also whether the front and back surfaces are accurate by detecting the amount of reflected light. Further, S2 consists of an optical sensor or a microsinch, and the image-receiving sheet 1-51 on which an image is formed in the pressure developing device 9, which is a jam sensor in the present invention, is heated and pressurized in the post-glossy device 21 and then discharged. paper tray 2
2.

FIG. 2 is a block diagram of the main parts of the copying machine.

The detection states of sensors such as Sl and S2 are input to a control unit 25 that controls the entire copying machine, and copy conditions, print start commands, etc. are input from an operation panel 27. In response to these human forces, the control unit 25 1) drives the S roller 6, the lower pressure corolla gb (the crafchi which transmits the driving force from the main motor to them), and the motor driver 16 for rotating the cam 14; Note that the operation panel 27 is provided with a display section that displays errors such as the occurrence of a jam, and when a jam is detected, the control section 25 displays a display that a jam has occurred.

FIG. 1 is a flowchart showing the main processing procedure of the copying machine.

When the print start command on the operation panel is operated, the copying process is started and a latent image is formed on the photosensitive pressure sensitive sheet 31.
The photosensitive pressure sensitive sheet on which the latent image has been formed is moved to the upper right part of the exposure area by the buffer roller 4. Simultaneously with the start of this exposure, the image receiving sheet 51 is fed from a manual feed tray or a paper cassette and is stopped by the PS roller 6. When the exposure process is completed, the pressure development process begins. First, the buffer roller 4 starts to move back and feeds the photosensitive pressure sensitive sheet to the pressure developing device section. At this time, the upper and lower pressure rollers 9a and 9b of the pressure developing device are in a pressure released state, and no offset occurs even if the photosensitive pressure-sensitive sheet is fed. Then, when a predetermined period of time has elapsed after the start of the backward movement of the buffer roller 4, feeding of the image receiving sheet held by the PS roller 6 is started.

First, the PS roller 6 is started to be driven at nl, and the image receiving sheet 51 is fed toward the pressure developing device 9. At the same time, timer t is started and counts 'l゛1 (n
2→n3). T1 is the time required for the image receiving sheet 51 to move from the PS roller 6 to the sensor S2, and if the sensor S2 does not detect the image receiving sheet during that time, it is determined that a jam has occurred, the PS roller 6 is stopped, and a message is displayed on the operation panel. A jam display is performed (n4.n5→n6). This prevents the subsequent pressure development process from being started, making it possible to prevent offset caused by jamming of the image-receiving sheet.

When sensor S2 detects the image receiving sheet, P
The S roller 6 stops, the motor 17 rotates, and the upper and lower pressure rollers 9a and 9b are pressurized (n7 to n13).
2, the image receiving sheet 51 is transferred from the sensor S2 to the pressure developing device 9.
T3 is the time required for the colas 9a and 9b to be completely pressurized under the vertical pressure in the pressure released state. With this control, when the leading edge of the image receiving sheet reaches the pressure developing device 9, the conveyance of the image receiving sheet 1 is stopped, and pressure is applied in this state. At this time, the conveyance of the photosensitive and pressure sensitive sheets is also stopped, and both sheets 31
．． 51 ensures that the pressure starts at the tip, thereby eliminating density unevenness in the formed image.

When the upper and lower pressure rollers 9a and 9b are pressurized in this manner, both rollers are then rotated and pressure development is started. The rotation of both rollers 9a and 9b pulls the photosensitive pressure-sensitive sheet and the image-receiving sheet, and pressurizes them in a superimposed state (n14).

Then, the rear end of the image receiving sheet passes the position of sensor S2,
Thereafter, when T2 has elapsed, the rotation of the pressure roller is stopped and the pressure development process is completed (n15 to n18). Then, the motor 17 rotates again to release the pressure on the upper and lower pressure rollers (
n19-n22).

As described above, according to this embodiment, the jam sensor S2 is provided immediately before the pressure developing device 9 and detects a jam in the image receiving sheet 1, so that the pressure on the photosensitive pressure sensitive sheet can be prevented even when there is no image receiving sheet. can be reliably prevented,
It is possible to prevent the image of the device 1 from becoming dirty. Furthermore, in this embodiment, the pressure of the pressure developing device is normally released, and during the development process, the pressure is applied and the pressure is released while the conveyance of the photosensitive pressure sensitive sheet and the image receiving sheet is stopped. The pressure start point and pressure end point can be set reliably, and off-cent can be more reliably prevented. Note that if the conveyance of the photosensitive pressure-sensitive sheet is not stopped when the leading edge of the image is located in the pressure developing device, or if a pressure developing device that is always kept in a pressurized state is used, the area between the latent images By exposing using an auxiliary light source (8 in FIG. 5), offset can be prevented. In this case as well, when the sensor S2 detects a jam in the image receiving sheet, it is natural that the start of the pressure development process is stopped by stopping the conveyance of the photosensitive pressure sensitive sheet or releasing the pressure.

(0 Effects of the Invention As described above, according to this invention, if the image-receiving sheet jams, the start of the pressure development process is stopped. It is possible to prevent offset from occurring and prevent the device and the image receiving sheet from getting dirty during the next image formation.Also, since the jam sensor is installed just before the pressure developing device, jam detection is reliable and offset prevention will also be ensured.

[Brief explanation of drawings]

Fig. 1 is a flowchart showing the pressure development processing procedure in a copying machine which is an embodiment of the present invention, Fig. 2 is a block diagram of the main parts of the copying machine, and Figs. 3 (A) and (B) are pressure development equipment. is a front sectional view of the same figure (A) when pressurized
) indicates the state when pressure is released. FIG. 4 is an external view of the pressure developing device, and FIG. 5 is a schematic front view of the entire copying machine. 6-PS roller, 9-pressure developing device, 3 4 9b-pressure roller, spring, cam, engaging part, motor, photosensitive pressure-sensitive sheet, image receiving sheet], jam sensor.

Claims (1)

[Claims] (1) In an image forming apparatus in which an image receiving sheet temporarily stopped by a PS roller and a photosensitive pressure sensitive sheet on which a latent image has been formed are fed to a pressure developing device and pressurized, a jam sensor is installed immediately before the pressure developing device. What is claimed is: 1. An image forming apparatus having a pressure developing device, further comprising means for stopping the start of pressure developing processing when the jam sensor detects a jam of an image receiving sheet.