JPH03205251A - Photosensitive sheet transporting device - Google Patents

Abstract

PURPOSE:To prevent slack and form a stable image by locking the pulling-out of a photosensitive sheet supplied from a feeding shaft and taking-up shaft by a locking mechanism and energizing a transport roller in the direction for pulling out the photosensitive sheet from the feeding shaft and the taking up shaft. 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 pressure development part P2. On the feeding shaft 1a, a brake is installed through a clutch, and the revolution is locked and released by turning ON/OFF a clutch. The transport roller 2 is axially supported in turnable manner on a guide part 21 at both the edge parts, and the guide part 21 is energized by a spring 22, in the direction for pulling out the photosensitive paper and connected with a driving block 25, and fixed on a driving belt 27. Accordingly, the slack and undulation within the light exposure part P1 are eliminated in the light exposure part 1, and when the lock for the feeding shaft 1a is released by the drive of the driving belt 27, the photosensitive sheet 1 can be pulled out, and the stable image formation can be carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION (Al Industrial Field of Application) This invention relates to a photosensitive sheet that is used in an image forming apparatus that pulls out a rolled photosensitive sheet and performs image forming exposure while keeping it stationary. This invention relates to improvements in conveyance devices.

M) 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 form an image, a scanning method is generally used in which the photosensitive sheet is exposed while being conveyed, but this method requires high accuracy in the conveying 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.

(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, it is extremely difficult to maintain the photosensitive sheet in a state without loosening or waving because no load is applied by pulling it out.

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

(Means for Solving Problem d1) 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 keeping the photosensitive sheet stationary on the exposure table for image forming exposure. The image forming apparatus includes: a lock mechanism that locks the photosensitive sheet from being ejected from the supply shaft and the take-up shaft; and a lock mechanism that urges the conveyance roller in a direction to pull out the photosensitive sheet from the supply shaft and the take-up shaft. A biasing member is provided.

In an image forming apparatus equipped with the photosensitive sheet conveying device of the present invention, when the withdrawal of the photosensitive sheet from the supply shaft and the take-up shaft is locked, the biasing member causes the photosensitive sheet to be pulled out from the supply shaft and the take-up shaft. A force is applied in the direction of pulling it out. For this reason, the photosensitive sheet is held in a state without loosening or waviness.

(f) Embodiment FIG. 4 is a diagram showing a schematic structure of an image forming apparatus equipped with a photosensitive sheet conveying device according to 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.
The film is wound onto the winding shaft 1b via the bath roller (transport roller) 2, the roller 9, and the pressure developing section P2.

A brake l2 is provided on the supply shaft 1a via a clamp 11. When the clutch 11 is off, the supply shaft 1a
The rotation of the photosensitive sheet 1 is controlled, and the withdrawal of the photosensitive sheet l from the supply shaft 1a is controlled.

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

The buffer roller 2 is biased in the direction of pulling out the photosensitive sheet 1 from the supply shaft 1a and the take-up shaft 1b, and is moved in the direction indicated by the arrow A. It is possible to move in the B direction. FIG. 1 is a diagram showing the structure of a photosensitive sheet conveying 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 portion 21 is connected to a drive block 23 by a spring 22. Spring 22
is a biasing member of the present invention, which biases the huffer roller 2 in the direction in which the photosensitive sheet 1 is pulled out from the supply shaft 1a and the take-up shaft 1b. On the other hand, a drive belt 27 is stretched between the pulleys 24, 25, and 26. A motor 28 is connected to the booby 24 via a clutch, and a drive belt 27
is rotated in the directions of arrows A' and B' in the figure.

The drive block 23 is fixed to the drive belt 27, and moves in the direction of arrow A or B as the drive belt 27 rotates. As a result, the buffer roller 2 moves in the direction of arrow A or B.

The pressure developing section P2 has upper and lower pressure developing rollers 7a, 7 in pressure contact with each other.
It is composed of 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 tor is manually determined. Depending on the amount of these photosensitive sheets pulled out, the supply shaft 1
It controls the clutch 11 that locks/releases the candle a, the motor 28 that moves the buffer roller 2 in the directions of arrows A and B, the pressure mechanism 32 that pressurizes/releases the pressure of the pressure developing rollers 7a and 7b, and the like.

Next, an outline of image-form precept processing will be explained.

The photosensitive sheet 1 pulled out from the supply shaft 1a is placed in the exposure section PL.
, 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. An image receiving sheet 6 is fed from a paper feeder 6a and superimposed on the latent image on the photosensitive sheet, and is pressed 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. When image forming processing is performed continuously, the photosensitive sheet is temporarily stocked onto the bath sofa section 2a by the buffer roller 2, whereby the exposure processing and the pressure development processing are performed simultaneously, thereby shortening the processing time.

The procedure for transporting the photosensitive sheet 1 during image 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.

<Single Image Forming Process> When the number of image sheets is one, the process is performed without moving the buffer roller 2. Figure 3 (A) is 1
FIG.

First, as shown in FIG. 2(A), the exposed portion P1 is image-formingly exposed and an 11-length latent image is formed (t. to 1+). At this time, the supply shaft 1a and the take-up shaft 1b are locked, and the photosensitive sheet 1-1 is not pulled out from the supply shaft 1a and the take-up shaft 1b. In this state, the photosensitive sheet 1 is biased in the pulling direction by the spring 22 attached to the roller 2, so it becomes loose. There is no undulation, and it is possible to create a latent image without distortion.

When the image forming exposure is completed, the (1+) 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 1
1. The length from the tip of the latent image to the pressure developing rollers 7a and 7b (inter-image area length) is a, and hereafter the 11-length latent image is expressed as l, ,
(or 112, 7!3...), the inter-image area is a
It is written as

Then, the image forming process transfers the rear end of the latent image 11 to the image receiving sheet 6.
The process ends when the image is copied to the winding shaft lb. ．． ! It is necessary to wind up the photosensitive sheet for an amount of 150 mm. When the photosensitive sheet is pulled out, the length of the photosensitive sheet is detected by the rotary encoder 8a, and when the photosensitive sheet corresponding to "IH+a" has been pulled out, the rotation of the supply shaft 1a and the take-up shaft 1b is stopped, and the photosensitive sheet is pulled out in a straight line. (t3). At this time, the rear end of the latent image IIO is exactly 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 l is positioned at the pressure development section P2 (t2).

When the rotary encoder 8a detects that "a" 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, the pressure developing rollers 7a and 7b rotate with both sheets 1 and 6 pressed, and pressure development processing is performed (tz to t3).

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 since the next image forming process will be performed in area l1, if the next image formation process is performed as is, A'' worth 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 encoder 8a, and when the length aJ 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 a plurality of sheets, the bath 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 thereof.

First, t, as in the case of processing one sheet. ~t. An image-forming exposure process is performed in the step (FIG. 2(A)). When the exposure process is completed, the supply shaft 1a is unlocked as shown in FIG. 2(B), and the hasher roller 2 moves in the direction of arrow A to pull out the photosensitive sheet from the supply shaft 1a (j z-
j + z). At this time, the take-up shaft 1b is in a locked state, and the photosensitive sheet 1 is pulled back from the take-up shaft 1b. When it is detected and pulled out by "11", the supply shaft 1a is closed, the buffer roller 2 is stopped, and the withdrawal is completed.

At this time, the stop timing of buffer roller 2 is set to supply shaft 1.
The lock timing is slightly delayed from the lock timing of a. As a result, the spring roller 2 is pulled by the spring 22, and the photosensitive sheet 1 is prevented from becoming loose and undulating.

At the end of this drawing, as shown in FIG. 2(C), the inter-image area a and the latent image 7!1 are drawn out by the roller 2, and the next latent image area l2 is located in the exposure portion P1. Then, area l2 is exposed with the next image-forming exposure light (1
＋■〜j z) A latent image is manifested. Immediately before the start of the exposure process for the second sheet, the winding shaft 1b and the puffer roller 2 start moving in the direction of arrow B, and the inter-image area a is wound onto the photosensitive sheet (FIG. 2(D)). At this time, the winding length of the photosensitive sheet is detected by the rotary encoder 9a.
When a long photosensitive sheet 1 is conveyed, the rotation of the winding shaft 1a is stopped and the locking mechanism 10 is closed to stop winding. Then, as shown in FIG. 2(E), the first latent image 1 is in a state facing the pressure developing section P2. Note that when winding is stopped, if the winding shaft 1b is stopped slightly later than the path roller 2, sufficient tension is applied to the photosensitive sheet 1, and even after the path roller 2 is stopped, the exposure process continues. There is no possibility that the photosensitive sheet l will become loose or wavy and the latent image will be distorted. After this, exposure processing is performed.

When the exposure process is completed, a latent image l2 is formed at tl4 to tl5.
photosensitive sheets 1 are pulled out from the supply shaft 1a (second
Figure (F). Then, the exposure process for the third sheet is performed (t, 5 to t17), and the 11-minute photosensitive sheet is wound up on the winding shaft 1b, and during this time, the pressure development process is performed (t1,
~t16). The pressure development process produces an image receiving sheet 6 on the latent image l1.
are superimposed, and while the latent image l1 faces the pressure developing rollers 7a and 7b, both rollers are pressurized. During this time, the length of the photosensitive sheet being pulled out is detected by the roller 8a, and the winding length is detected by the roller 9a. Controls such as locking the supply shaft 1a and moving/stopping the huffer roller 2 are performed.

The above operations from tl4 to tit are performed for the number of images, and t.
When the final exposure process is completed, the final operation begins. First, as before, attach a photosensitive sheet with a latent image of 17 minutes.
At tl9, pull out from the supply shaft 1a (Fig. 2 (F)
), and then the latent images i,, -1 are subjected to pressure development processing from tl9 to tzo (FIG. 2(E)).

Then, the supply shaft 1a is unlocked and the take-up shaft 1b is turned to move the bath roller 2 in the direction of arrow A to draw out the photosensitive sheet for the inter-image area a.
. ~jz+), and the last latent image l. is subjected to pressure development treatment (t2, to t2■). As a result of the above operations, Figure 2 (A
), but at this time an unused photosensitive sheet is located in the inter-image area a. So t2
(2) In tZ3, the photosensitive sheet is pulled back to prevent the photosensitive sheet from being wasted.

In this embodiment, since the feed amount of the photosensitive sheet 1 from the supply shaft la is detected by the rotary encoder 8a9a, it is not necessary to control the movement of the differential roller 2 so precisely, and the cost for these precisions can be reduced. It can be done. Also, the lock of the supply shaft 1a. Winding shaft 1
Since the timing of stopping the locking roller 2 in b can be accurately operated with almost no fluctuation after receiving a lock signal or a stop signal, the range of variation in the tension applied to the photosensitive sheet can also be reduced. Furthermore, conventionally, in a conveying device that does not include a biasing member (spring 22), in order to apply tension to the photosensitive sheet 1, the supply shaft 1a is locked and the take-up shaft tb is slightly rotated to apply torque. However, in this device, the radius of the take-up shaft 1b changes as the photosensitive sheet 1 is used, so there is a risk that the sheet tension will change. To prevent this, a conveying roller (huffer roller 2) Although it was necessary to widen the mechanical margin, this is not necessary with the device of this embodiment.

In this embodiment, the conveyance roller (bath sofa roller 2) is supported by the movable block 23, but the conveyance roller may be supported by a fixed block. In this case as well, the conveying roller is urged in the direction of drawing out the photosensitive sheet 1 from the supply shaft 1a and the take-up shaft 1b by a biasing member such as a spring.

(Effects of the Invention As described above, according to this invention, a force is applied in the direction of pulling out the photosensitive sheet from both shafts while the drawing out of the photosensitive sheet from the supply shaft and the winding shaft is locked. Tension is applied to the film to prevent it from loosening and waving.This prevents distortion of the latent image during exposure processing, making it possible to form images of stable quality.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a partial structure of a photosensitive sheet conveying device according to an embodiment of the present invention, and FIGS. 2 (A) to (F) show operating states of the photosensitive sheet conveying device during image forming processing. Figure, 3rd
Figures (A) and (B) are time charts related to the photosensitive sheet conveying device during image forming processing, Figure 4 is a schematic front view of an image forming apparatus equipped with the same device, and Figure 5 is a schematic diagram of the image forming apparatus. It is a partial block diagram. Reference Signs List 1-photosensitive sheet, 1a-supply shaft, 1b-take-up shaft, 2-housing roller, 7a, 7b-pressure developing roller, 21-guide portion, 22-spring, 23-driving block, 24
．． 25. 26-pulley, 27 drive belt, 28-motor.

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 that locks the photosensitive sheet from being pulled out from the take-up shaft, and a biasing member that biases the conveyance roller in a direction to pull out the photosensitive sheet from the supply shaft and the take-up shaft. Photosensitive sheet conveyance device.