JPH0830888B2 - Image forming method - Google Patents

Description

Description: (a) Field of Industrial Application The present invention relates to an image forming method for forming an image using a light and pressure sensitive media sheet, and more particularly to setting of a conveyance speed of the media sheet.

(B) Conventional Technology In recent years, development of an image forming apparatus for forming an image using a media sheet in which microcapsules (particle diameter of about 5 μm) encapsulating a photocurable material, a dye and the like are dispersed and coated on a resin film has been developed. It is being advanced. An image is formed on the media sheet by passing through the exposure section and the pressure development section. That is, in the exposure section, the media sheet is exposed with image forming light such as reflected light of an original so that a partial microcapsule is cured to form a latent image, and in the pressure development section, a receiver sheet is superposed on the latent image. By applying pressure, the uncured microcapsules are destroyed, the dye flows out, and an image is formed on the receiver sheet.

(C) Problems to be Solved by the Invention By the way, when an image is formed using the above-mentioned media sheet, the exposure speed and the pressure development speed (both speeds = media are used) depending on the light sensitivity and pressure sensitivity of the media sheet (microcapsules). Sheet conveyance speed) must be set.
However, these sensitivities, particularly the photosensitivity, are low, and the conveyance speed of the media sheet is set to be slow in accordance with the conventional low sensitivities, resulting in a problem that the processing time of the entire image formation becomes long.

Therefore, an object of the present invention is to provide an image forming method capable of shortening the image forming processing time by changing the processing speed for each process during the image forming processing.

(D) Means for Solving the Problem In the image forming method of the present invention, a roll-shaped media sheet having photosensitivity is passed through the exposure section while being conveyed while the passage to the pressure development section is regulated. The first step of forming a latent image and storing the media sheet that has passed through the exposure unit between the exposure unit and the pressure developing unit, and the medium sheet in the pressure developing unit with the pressure of the pressure developing unit released. A second step of passing the leading edge of the latent image to the pressure developing section, and a third step of passing a receiver sheet on the latent image with the pressure developing section under pressure and passing the pressure developing section. Further, the media sheet transport speed in the first step is set according to the light sensitivity of the media sheet, and the media sheet transport speed in the third step is the pressure sensitivity of the media sheet. With corresponding sets in, the media sheet conveyance speed at the time of the second step, characterized in that set faster than the media sheet conveying speed when the first and third step.

(E) Action The conveying speed of the media sheet during exposure (during the first step) and pressure development (the third step) is set too high because the media sheet has sensitivity (light sensitivity, pressure sensitivity) characteristics. I can't do it. However, at any other time, that is, while the leading edge of the latent image formed on the media sheet is transported to the pressure developing unit, no processing is performed, so that an appropriate transport speed can be set. Therefore, according to the present invention, at least after the exposure process is completed and while the leading edge of the latent image formed on the media sheet is conveyed to the pressure development unit, the conveyance speed of the media sheet is increased while the pressure of the pressure development unit is released. By doing so, the process time taken during that time is shortened, and as a result, the time required for the entire image forming process is shortened.

(F) Embodiment FIG. 2 is a schematic front view of a copying machine for forming an image using a media sheet.

An original table 1 made of transparent hard glass is provided on the upper surface of the main body of the copying machine, and an original to be copied is placed on the original table 1. Below the platen 1, a light source, a mirror,
An optical system 2 including a lens and the like is provided, scans a document on the document table 1, and guides the reflected light to an exposure unit described later.

The media cartridge 3 is on the left side of the center of the copying machine.
Is detachably attached to the main body of the copying machine. The media cartridge 3 has a supply shaft 31 and a take-up shaft 32, and an unused media sheet 4 is wound around the supply shaft 31. Supply axis
The media sheet 4 of 31 is pulled out from the media cartridge 3 and taken up by the take-up shaft 32 via the exposure section P1, the buffer roller roller 5 and the pressure developing section P2. The supply shaft 31 is urged in the direction to pull back the media sheet 4, and the take-up shaft 32 is urged in the direction to wind the media sheet 4. The above-mentioned document reflected light is guided to the exposure section P1,
A latent image is formed on the media sheet. Pressure development part P2
Is composed of a pressure developing device 6. The pressure developing device 6 has a pair of pressure rollers 61 and 62, and presses the media sheet and the receiver sheet between them (P2). Reference numeral 63 denotes a backup roller for urging the upper pressure roller 61 downward in the axial direction without unevenness. Actually, the backup roller 63 and the pressure roller 62 are urged in a direction in which they are pressed against each other. The upper and lower pressure rollers 61, 62 are pressed against each other. Pressure roller 61 (backup roller 63)
The pressure roller 62 and the pressure roller 62 can be pressurized / released by a spring, a cam, a motor for rotating the cam, and the like (not shown), and are in a released state except during pressure development, as will be described later. In addition, the pressure when pressurizing the pressure developing device is
It is around 100 kg / cm.

The buffer roller 5 is moved by an arrow F by a motor (not shown).
And can be moved in the R direction. When the buffer roller 5 moves in the arrow F direction, the media sheet 4 on the supply shaft 31 is pulled out, and the media sheet 4 passes through the exposure section P1 at a predetermined speed (1/2 of the buffer roller moving speed). The exposed media sheet is stocked by the buffer roller 5 in the upper right part (buffer part) of the exposure part P1. Then, when the buffer roller 5 moves in the direction of arrow R, the media sheet in the buffer section is sent out in the pressure developing section P2 direction, and pressure developing is performed in the pressure developing section P2.

A lock mechanism 7 is provided between the buffer roller 5 and the pressure developing device 6. The lock mechanism 7 holds the media sheet 4 at this position so that it cannot be conveyed. Specifically, sandwiching members are provided above and below in the thickness direction of the media sheet, and the sandwiching members are moved in a direction in which they are pressed against each other by a solenoid. The nipping member and the solenoid are provided at both ends of the media sheet 4, and nipping and locking the media sheet at both ends. When the solenoid is turned off, the media sheet is pinched, the media sheet 4 is not unnecessarily wound around the winding shaft, and the media sheet on the winding shaft is not pulled back. When the solenoid is turned on, the locked state is released so that the media sheet 4 can be sent to the pressure developing section P2 and the winding shaft 32.

A paper cassette 81 and a manual feed tray 82 are provided on the right side surface of the copying machine body. A receiver sheet 9 is stored in the paper cassette 81 and the manual feed tray 82. The receiver sheet 9 is fed by a sheet feeding device and temporarily stopped at the position of the registration roller 10. Registration roller 10
Rotates at a predetermined timing to feed the receiver sheet 10 to the pressure developing unit P2. The predetermined timing is the timing when the tip of the receiver sheet coincides with the tip of the latent image on the media sheet 4 in the pressure developing section.

Reference numeral 11 behind the pressure developing device 6 is a heating device for sharpening an image on the receiver sheet, and reference numeral 12 is a discharge tray to which the image-formed receiver sheet is discharged.

FIG. 1 is a time chart during image formation in the copying machine configured as described above.

First, the exposure process is started at t ₁ . That is, the buffer roller 5 moves in the direction of arrow F and pulls out the media sheet from the supply shaft 31. At this time, the pressure developing device 6 is in the pressure released state and the lock mechanism 7 is in the locked state. At the same time when the media sheet 4 is pulled out, the optical system 2 scans the document on the document table and guides the reflected light to the exposure section P1. This cures the partial microcapsules on the media sheet 4 to form a latent image. The speed of pulling out the media sheet at this time is
It is about 5 mm / sec. The light sensitivity of the media sheet is low,
Moreover, since the light amount of the optical system is also limited by the light source and the like, only slow exposure can be performed.

When the exposure is completed at t ₂ , the buffer roller 5 immediately moves in the R direction at a high speed (about 100 mm / sec).
This is an operation of moving the leading edge of the latent image to the pressure developing unit P2. At the end of exposure, the leading edge of the latent image is at the position indicated by A in FIG. 2 (the position that was P1 at the start of exposure). After moving point A to pressure developing unit P2, pressure is applied to points A and beyond. This is for developing. Therefore, this operation has nothing to do with the actual process of image formation, and it is desirable that the operation is completed in the shortest possible time, and the time is shortened by conveying the media sheet at a high speed. At this time, the lock mechanism 7 is turned on, and the media sheet 4 loosened by the movement of the buffer roller 5 is taken up by the take-up shaft 32.

On the other hand, the registration roller 10 rotates in anticipation of the timing when the leading edge of the latent image on the media sheet is positioned at the pressure developing section P2, and the leading edge of the latent image and the leading edge of the receiver sheet are positioned at the pressure developing section P2 at the same time. And the pressure developing device 6
Is pressurized, and pressure development is started at t ₃ . The pressure development speed is set according to the pressure sensitivity of the media sheet 4, and is about 60 mm / sec in this example. Since the light sensitivity and the pressure sensitivity of the media sheet differ depending on the sheet type, the media sheet transport speed during exposure and pressure development is set according to the type of the media sheet.

As described above, the media sheet conveyance speed step in this image forming process is divided into several steps (at least the exposure step, the latent image leading edge adjusting step, the pressure developing step),
Processes that are not related to pressure sensitivity (latent image tip alignment process)
Then, by conveying the media sheet at a speed as fast as possible, it is possible to shorten the image forming processing time as a whole.

(G) Effect of the Invention According to the present invention, after the exposure step, the leading edge of the latent image formed on the media sheet is conveyed to the pressure developing section.
In the process, in order to speed up the conveyance speed of the media sheet while the pressure of the pressure development section is released, the processing time as a whole of the image forming process is shortened and the media sheet is conveyed at high speed without being pressed. In addition, wrinkles do not occur on the media sheet and skew feeding does not occur. Further, since the pressure developing unit does not carry out high speed conveyance, it is not necessary to switch the speed of the pressure developing unit.
The speed of the pressure developing unit can be easily controlled.

[Brief description of drawings]

FIG. 1 is a time chart during image formation in a copying machine which is an embodiment of the present invention, and FIG. 2 is a schematic front view of the copying machine. 4 ... Media sheet, 5 ... Buffer roller, 6 ... Pressure developing device, 7 ... Lock mechanism, 9 ... Receiver sheet, 31 ... Supply shaft, 32 ... Winding shaft, P1 ... Exposure unit, P2 ... Pressure developing unit.

Claims (1)

[Claims] 1. A latent image is formed by passing a roll-shaped media sheet having photosensitivity and pressure while passing through the exposure section while forming a latent image and passing through the exposure section. The first step of storing the sheet between the exposure section and the pressure developing section, and passing the media sheet through the pressure developing section with the pressure of the pressure developing section released to convey the leading edge of the latent image to the pressure developing section. And a third step of allowing a receiver sheet to be superposed on the latent image and passing through the pressure developing section while the pressure developing section is under pressure, further comprising the step of: Of the media sheet is set in accordance with the light sensitivity of the media sheet, the media sheet transportation speed in the third step is set in accordance with the pressure sensitivity of the media sheet, and the media sheet speed in the second step is set. An image forming method characterized in that a media sheet transport speed is set to be higher than the media sheet transport speed in the first and second steps.