JPH03205250A - Photosensitive sheet transporting device - Google Patents

Abstract

PURPOSE:To prevent the slack of a sheet with the simple constitution by allowing a feeding shaft and a taking-up shaft to be locked, energizing a transport roller in the direction for pulling out a photosensitive sheet from both the shafts and allowing the photosensitive sheet having one image formation portion to be shifted by an energizing force to a pulling-out position. CONSTITUTION:A photosensitive sheet 1 is wound on a feeding shaft 1a, and taken up on a taking-up shaft 1b through a roller 8, light exposure part P1, transport roller 2, roller 9, and a development part P2. The revolution of the feeding shaft 1a is locked by turning ON/OFF a clutch, and also a lock released state can be generated. The transport roller 2 is always energizing in the pulling direction by a weight 24. Accordingly, in the state where both the shafts 1a and 1b are locked, the slack and undulation within the range of the light exposure part P1 are eliminated on the photosensitive paper 1. After sensing light, the lock for the feeding shaft 1a is released, and the photosensitive paper sheet is pulled out from the feeding shaft 1a by the portion of formation of one sheet by the shift in the A direction by the weight 24 of the transport roller 2, and after locking, the taking-up shaft 1b is revolved, and the photosensitive paper 1 after light exposure is taken up through the development part P2.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Field of Application This invention relates to an image forming apparatus in which a rolled photosensitive sheet is pulled out and kept stationary for image forming exposure. This invention relates to improvement of a photosensitive sheet conveying device.

(b) Conventional technology Using a photosensitive sheet coated with pressure-sensitive microcapsules, a latent image is formed on the photosensitive sheet by exposing the photosensitive sheet to image-forming light such as light reflected from an original;
There is an image forming apparatus that develops and transfers the latent image onto the image-receiving sheet by superimposing an image-receiving sheet on the latent image and applying pressure.

When exposing the photosensitive sheet to image formation, a scanning method is generally used in which the photosensitive sheet is exposed while being conveyed. However, this method requires high precision in the conveyance speed of the photosensitive sheet, and in particular, When performing density printing, there is a problem in that considerably high precision is required. Therefore, a static exposure method has come into use in which the entire image is exposed at once while the photosensitive sheet is stopped.

Further, when performing image forming processing using a static exposure method, there is an image forming apparatus that performs exposure processing and pressure development processing at the same time to save time. A conveyance roller is installed between the exposure section and the pressure development section, and moves with the photosensitive sheet pulled out from the supply shaft suspended, and by moving the conveyance roller, the exposed photosensitive sheet is temporarily stored in the bath sofa section. Then, while performing the next exposure process, the photosensitive sheet in the buffer section is sent to the pressure developing section.

(C) Problems to be Solved by the Invention When exposing a photosensitive sheet to form an image, it is desirable that a certain amount of tensile load be applied to the photosensitive sheet. This is to prevent image distortion caused by loosening and waviness of the photosensitive sheet during exposure processing. When exposure processing is performed by the scanning method, the photosensitive sheet is pulled out during the exposure processing, so that the photosensitive sheet does not become loose or wavy due to the load of pulling out. however,
In the case of the static exposure method, there is no load due to pulling out, so there is slack. It has been very difficult to maintain a photosensitive sheet without waviness.

SUMMARY OF THE INVENTION An object of the present invention is to provide a photosensitive sheet conveying device that can hold a photosensitive sheet under tension during exposure processing in a static exposure type image forming apparatus.

(di Means for Solving the Problems) This invention involves winding up a photosensitive sheet pulled out from a supply shaft onto a take-up shaft via an exposure table and a conveyance roller, and making the photosensitive sheet stationary on the exposure table to perform image forming exposure. The image forming apparatus includes a lock mechanism that locks the photosensitive sheet from being pulled out from the supply shaft and the take-up shaft; The present invention is characterized in that it is provided with a roller pulling mechanism that moves the image-shaped precept photosensitive sheet to a position where it is pulled out by the urging force.

(Q) Function When the image forming apparatus equipped with the photosensitive sheet conveying device of the present invention locks the withdrawal of the photosensitive sheet from the supply shaft and the take-up shaft, the photosensitive sheet is moved to the supply shaft and the take-up shaft by a roller tension mechanism. A biasing force is applied in the direction of pulling it out from the shaft, which causes the photosensitive sheet to slacken. Retained without rippling.

The roller pulling mechanism moves the transport roller to a position where at least one image-shaped photosensitive sheet is pulled out. When the supply shaft is unlocked when the exposure process is completed, the photosensitive sheet is pulled out from the supply shaft by the urging force of this roller pulling mechanism and stored in the bath sofa section. The pull-out length of this photosensitive sheet is determined by the tie a that locks the supply shaft.
The photosensitive sheet can be pulled out to any desired length. Then, during the next exposure process, if the locking mechanism on the take-up shaft side is released and the photosensitive sheet in the bath sofa section is sent to the take-up shaft via the pressure development section, the exposure processing and pressure development processing are performed simultaneously. This will save you money. At this time, the photosensitive sheet is also stretched by the roller tensioning mechanism, so that the photosensitive sheet does not become loose or wavy.

(f) Embodiment FIG. 4 is a diagram schematically showing the structure of an image forming apparatus equipped with a photosensitive sheet II feeding device, which is an embodiment of the present invention.

A photosensitive sheet 1 coated with photosensitive and pressure-sensitive microcapsules is wound around a supply shaft 1a, and is connected to a roller 8 and an exposure section P.
1, Buffalo roller (vIi feed roller) 2, Roller 9,
The film is wound up onto the winding shaft 1b via the pressure developing section P2.

A brake 12 is provided on the supply shaft 1a via a clutch 11. When the clutch 11 is off, the supply shaft 1a
The rotation of the photosensitive sheet 1 is stopped, and the extraction of the photosensitive sheet 1 from the supply shaft 1a is locked. Conversely, when the clutch 11 is in the ON state, the supply shaft 1a is free to rotate, and the photosensitive sheet can be pulled out from the supply shaft 1a.

Rollers 8.9 arranged in the conveyance path of the photosensitive sheet 1
A rotary encoder 8a9a is attached to each of the rotary encoders 8a9a to detect the amount of rotation of the roller 8.9. The rotation amount of this roller 8.9 corresponds to the conveyance length of the photosensitive sheet 1, and the rotation amount of the rotary encoder 8.9 corresponds to the conveyance length of the photosensitive sheet 1. The operation timing of the buffer roller 2 is controlled by the photosensitive sheet conveyance length determined by 9a.

The buffer roller 2 is urged in a direction to pull out the photosensitive sheet 1 from the supply shaft 1a and the take-up shaft lb, and is movable in the directions of arrows A and B. FIG. 1(A) is a diagram showing the structure of a photosensitive sheet conveyance section including a buffer roller 2. As shown in FIG.

The buffalo roller 2 is rotatably supported by the guide portion 21 at both ends. The guide section 21 is movable in the directions of arrows A and B along a rail (not shown) provided on the main body of the image forming apparatus. A wire 22 is fixed to the guide portion 21, and a weight 24 is attached to the other end of the wire 22 via a bobbin 23. The weight of this weight 24 is balanced by the brake that locks the take-up shaft and the lock mechanism of the supply shaft 1a, so that when the supply shaft 1a and the take-up shaft 1b are locked, the photosensitive sheet is removed from the supply shaft 1a and the take-up shaft 1b. It is never brought out. At this time, the weight 24 pulls the photosensitive sheet 1. Maintain it in a state with no tension or undulations.

The pressure developing section P2 has upper and lower pressure developing rollers 7a, 7 in pressure contact with each other.
It is structured by b. The pressure developing rollers 7a and 7b can be pressurized/released by a pressure mechanism including a spring and an eccentric cam (not shown), and are pressurized only during pressure development processing.

FIG. 5 is a block diagram of the main parts of the printer.

The entire printer is controlled by a control unit 31, which controls the amount of withdrawal and rewinding of the photosensitive sheet 1 from the supply shaft 1a detected by the rotary encoder 8a, and the amount of photosensitive sheet 1 transferred to the winding shaft 1b detected by the rotary encoder 9a. The amount of winding and rewinding of one sheet 1 is manually determined. Depending on the amount of these photosensitive sheets pulled out, the supply shaft 1
It controls the clutch 11 that locks/unlocks a, the motor 28 that moves the buffer roller 2 in the directions of arrows A and B, the pressure mechanism 32 that presses/releases the pressure on the pressure developing rollers 7a and 7b, and the like.

Next, an outline of the image forming process will be explained.

The photosensitive sheet 1 pulled out from the supply shaft 1a is placed in the exposure section P1.
, image-forming exposure light guided from an upper optical system (light emitted from a light source 5 to a liquid crystal panel 4 on which an image has been written by a semiconductor laser 3, and this light reflected by the liquid crystal panel 4) It is exposed to light and a latent image is formed.

This image-forming exposure is static exposure performed with the photosensitive sheet 1 stopped. A paper cassette 6 is placed on the latent image on the photosensitive sheet.
Image receiving sheets 6 are fed from a, stacked on top of each other, and pressurized in a pressure developing section P2. As a result, the latent image on the photosensitive sheet is developed and transferred to the image receiving sheet 6. In addition, when performing image-form precept processing continuously, the buffer roller 2
By temporarily moving the photosensitive sheet to the bathtub portion 2a, exposure processing and pressure development processing are performed simultaneously, thereby shortening the processing time.

The procedure for transporting the photosensitive sheet 1 during image forming processing will be described in detail. FIG. 2 is a diagram showing the conveyance state of the photosensitive sheet during image formation, and FIG. 3 is a time chart.

One Image Formation Process> When the number of images to be formed is one, the process is performed without moving the batho roller 2. Figure 3 (A) is 1
3 is a time chart during image forming processing of two sheets.

First, as shown in FIG. 2(A), the exposed portion PL is image-formingly exposed to form a latent image of l1 length (t. to 1+). At this time, the supply shaft 1a and the take-up shaft 1b are locked, and the photosensitive sheet 1 is not pulled out from the supply shaft 1a and the take-up shaft 1b. In this state, the photosensitive sheet 1 is urged in the drawing direction by the weight 24, so that it does not become loose or wavy, and a distortion-free latent image can be formed.

When the image forming exposure is completed (t1), the photosensitive sheet 1 is pulled out. The supply shaft 1a and the take-up shaft 1b are unlocked, and the photosensitive sheet 1 is pulled out from the supply shaft 1a and wound onto the take-up shaft 1b. Here, the length of the latent image is l+
, the length from the tip of the latent image to the pressure developing rollers 7a, 7b (
Hereinafter, the latent image of J length will be expressed as l1 (or 12, 1, . . . ), and the inter-image area will be expressed as a.

Then, the image formation process transfers the rear end of the latent image l1 to the image receiving sheet 6.
The winding shaft 1b ends when the image is copied to ``1l''.
+a'' worth of photosensitive sheets must be wound up. When drawing out the photosensitive sheet, the drawing length is detected by rotary encoders 8a and 9a, and r7B, +a
When the amount of photosensitive sheets corresponding to "1" have been pulled out, the rotation of the supply shaft 1a and the take-up shaft 1b is stopped, and the withdrawal of the photosensitive sheets is stopped (t,). At this time, the rear end of the latent image l1 is located at the pressure developing section P2.

During this extraction process, the pressure development process is started when the leading edge of the latent image l1 is located at the pressure development section P2 (t2).

When the rotary encoder 9a detects that aJ worth of photosensitive sheets have been pulled out, the pressure developing rollers 7a, 7b
is pressed, and the image receiving sheet 6 is superimposed on the latent image l on the photosensitive sheet. Then, with both sheets 1.6 pressed, the pressure developing rollers 7a and 7b rotate to perform pressure development processing (tz to t3). The speed of this pressure development process is determined by the rotational speed of the pressure development rollers 7a and 7b.

When the pressure development process is completed, the supply shaft 1a and the take-up shaft 1b rotate in the opposite direction, and the photosensitive sheet on the take-up shaft 1b is pulled back (t3
~t4). At the end of the pressure development process, all of the photosensitive sheet in the area after the pressure development section P2 is unused, but the next image formation process will be performed in the area l, so if the next image formation process is performed as it is, it will be ra. , 1 of photosensitive sheets are wasted.

Therefore, the photosensitive sheet is rewound by an amount "a" to prevent wastage. The rewinding length of the photosensitive sheet 1 is detected by the rotary encoders 8a, 9a, and when the length "a" is reached, the supply shaft 1a and the take-up shaft 1b are locked and the rewinding process is completed.

<Image formation processing for multiple sheets> When performing image forming processing for multiple sheets, the buffer roller 2 is used in order to simultaneously perform exposure processing and pressure development processing to save processing time. FIG. 3(B) is a time chart during continuous image forming processing.

First, in tlO""tl1 as when processing one sheet?
Image exposure processing is performed (FIG. 2(A)). When the exposure process is completed, as shown in FIG. 2(B), the supply shaft 1a
will be unlocked. Then, the bumper roller 2 is moved in the direction of arrow A by the force of the weight 24 and pulls out the photosensitive sheet from the supply shaft 1a (j++ to t1). At this time,
The take-up shaft 1b is in a locked state, and the photosensitive sheet 1 will not be pulled back from the take-up shaft 1b. Further, the length of the photosensitive sheet 1 being pulled out is detected by the rotary encoder 8a, and when the photosensitive sheet 1 is pulled out by "β1", the supply shaft 1a is locked and the pulling out is stopped. However, even after the supply shaft 1a is closed, the photosensitive sheet 1 is still being pulled by the weight 24, so the photosensitive sheet 1 becomes loose. No ripples will occur.

At the end of this drawing, the inter-image area a and the latent image l are drawn out by the bumper roller 2, as shown in FIG. 2(C), and the next latent image area 12 is located at the exposure portion P1. The area 1t is then exposed to the next image-forming exposure light (t
IF"" t 14) A latent image is formed. Immediately before the start of the exposure process for the second sheet, the lock on the winding shaft 1b is released, and the winding shaft 1b rotates in the forward direction to wind up the photosensitive sheet on the bath sofa section 2a (Fig. 2 (D)). . The winding length of the photosensitive sheet is detected by the rotary encoder 9a,
When the photosensitive sheet 1 of length aj is conveyed, the rotation of the winding shaft la is stopped, and the winding shaft 1b is locked to stop the winding.Then, as shown in FIG. , the first latent image II is in a state facing the pressure developing section P2.After this, the weight 24 pulls the photosensitive sheet 1 and loosens it, so that no waving occurs. Distortion is prevented.After this, exposure processing is performed.

When the exposure process is completed, the photosensitive sheet 1 corresponding to 12 latent images is pulled out from the supply shaft 1a at tw to tl5 (FIG. 2(F). Then, the exposure process for the third sheet is performed (
The photosensitive sheet for t+s~t+, )lt is wound up on the winding shaft 1b, during which pressure development processing is performed (t's~
t). In the pressure development process, the image receiving sheet 6 is superimposed on the latent image l1, and the latent image 11 is transferred to the pressure developing roller 7a.
, to 7b? Both rollers are pressurized while facing toward each other. During this time, the pull-out length of the photosensitive sheet is detected by the roller 8a, the winding length is detected by the roller 9a, and the supply shaft 1a is locked.

Above tl4~tl? The following operations are performed for the number of images to be formed.tt
When the final exposure process is completed at s, the final operation begins. First, as before, place a latent image l7 on the photosensitive sheet.
``At tl9, pull out from the supply shaft 1a.
)), then at t I 9”” t 20 the latent image l■
, is subjected to pressure development treatment (Fig. 2(E)).

Then, the take-up shaft 1b is locked, and immediately after that, the supply shaft la (
7) By releasing the lock, move the bath roller 2 in the direction of arrow A and pull out the photosensitive sheet for the inter-image area a, Ctz. ~t21), and the final latent image l0
is subjected to pressure development treatment (t21 to t2■). As a result of the above operations, the state returns to the initial state shown in FIG. 2(A), but at this time an unused photosensitive sheet is located in the inter-image area a. Therefore, the photosensitive sheet is pulled back from t22 to tt3 to prevent the photosensitive sheet from being wasted.

FIG. 1(B) shows the photosensitive sheet 1 of the buffer roller 2 being fed to the supply shaft 1a. FIG. 7 is a diagram illustrating another example of a roller pulling mechanism that urges the roller in the direction of pulling it out from the take-up shaft 1b. In this example, the guide portion 21 supporting the buffer roller 2 is biased in the direction in which the photosensitive sheet 1 is pulled out by a spring 25 whose one end is fixed to the main body of the image forming apparatus. In this case as well, the photosensitive sheet 1 can be maintained without loosening or waving as in the example shown in FIG. Can be stocked.

In this embodiment, the buffalo roller is moved without a motor, and the buffalo roller moving mechanism can be constructed at low cost.

(g) Effects of the Invention As described above, according to the present invention, a force is applied from both wheels in the direction of pulling out the photosensitive sheet by the pulling mechanism with the photosensitive sheet being pulled out from the supply shaft and the winding shaft in a locked state. , tension is applied to the photosensitive sheet to prevent it from loosening and waving. This prevents latent image distortion during exposure processing, making it possible to form images of stable quality.

In addition, the conveyance roller can be moved by the pulling mechanism to pull out the photosensitive sheet, and this mechanism does not require a motor, gear, etc. to move the conveyance roller, so the cost of the device can be reduced. .

[Brief explanation of drawings]

FIG. 1(A) is a diagram showing a partial configuration of a photosensitive sheet conveying device according to an embodiment of the present invention, and FIG. 1(B) is a diagram showing a configuration of another embodiment. Figures 2 (A) to (F) are diagrams showing the operating state of the photosensitive sheet conveying device during image forming processing, and Figures 3 (A) and (B) are diagrams showing the photosensitive sheet conveying device during image forming processing. FIG. 4 is a schematic front view of an image forming apparatus equipped with the same apparatus, and FIG. 5 is a block diagram of essential parts of the image forming apparatus. 1-photosensitive sheet, 1a, 2-buffer roller, A, 21-guide portion, W, 24 one weight, 25 forming device main body. Supply shaft, 1b-take-up shaft, 7a, 7b-pressure development row 22-wire, 23-pooh spring, 26-image

Claims (1)

[Claims] (1) In an image forming apparatus that winds up a photosensitive sheet pulled out from a supply shaft onto a take-up shaft via an exposure table and a conveyance roller, and performs image-forming exposure by keeping the photosensitive sheet stationary on the exposure table, the supply shaft and a locking mechanism for locking the photosensitive sheet from being pulled out from the take-up shaft, and urging the conveying roller in a direction to pull out the photosensitive sheet from both the shafts, and to a position where at least one image-forming photosensitive sheet is pulled out. A photosensitive sheet conveying device comprising: a roller pulling mechanism that is moved by the biasing force.