JPH03215859A - Image forming device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention relates to an image forming method in which an image is formed using a photosensitive donor sheet and a receiver sheet to which a latent image formed by exposure on the donor sheet is transferred. The present invention relates to a forming device.

(b) Prior art FIG. 6 shows an image forming apparatus using a donor sheet coated with microcapsules containing a photocurable material and an image forming agent, and a receipt sheet coated with a developing material that causes the image forming agent to develop color. It is a general configuration diagram.

The light beam oscillated by the semiconductor laser 32 irradiates and exposes the donor sheet 51 on the exposure plate 60 through the optical device 3 including a triangular mirror, a liquid crystal screen, a mirror, and the like. This exposure is
This is done by freeing the supply shaft 53, moving the bath roller 61 in the eight directions of the arrow, and moving the unexposed portion of the donor sheet to the exposure position. The exposed microcapsules are cured by exposure, and a selectively cured image (latent image) is formed on the donor sheet. When the exposure is completed, the take-up shaft 54 is rotated to move the bumper roller 61 in the direction of arrow B, thereby transporting the latent image area on the donor sheet to the pressure developing section 6. On the other hand, the receiving sheet 41 is fed from the paper feed section 4 to the pressure developing section in synchronization with the latent image. The donor sheet 51 and the receiver sheet 41 are passed between pressure rollers 63 and 64 in an overlapping state to be pressurized. As a result, the uncured microcapsules on the donor sheet are destroyed, and the image forming agent flows out and reacts with the developing material on the receiver sheet to form a color. For multi-image formation, the used donor sheet is wound onto the take-up shaft 54, and when the last pressure development is completed, the rear end of the latent image is exposed to light for effective use. Reverse feed to the vicinity of the position. On the other hand, the receiver sheet 41 is subjected to heat treatment in the glossing device 7 and is discharged to the paper discharge section 8.

In the above-described image forming apparatus, since the latent image on the roll-shaped donor sheet 1 is transferred to the cassette-like receiver sheet, it is necessary to set the image position on the receiver sheet, that is, the timing of the latent image on the donor sheet 1. It is necessary to feed the Recchiha sheet accordingly.

Conventionally, the method of setting the feeding timing of the receiver sheet, that is, the timing of starting driving of the timing roller, is based on, for example, the start of movement of the buffer roller 61 in the direction of arrow B in the case of the above-mentioned image forming apparatus. , based on the conveyance timing of the donor sheet.

(Problem to be solved by the Cl invention) In the conventional method of setting the feeding timing, the feeding timing is uniquely set based on the feeding timing of the donor sheet.
It is independent of the amount of donor sheet withdrawal. However, the amount of donor sheet pulled out from the supply shaft after the previous exposure is not constant but changes. This is done by leaving the supply shaft free when pulling out the donor sheet, so for example, even if the huffer roller stops pulling out, the donor sheet will be pulled out excessively due to the inertia of the supply shaft and become slack, and tension will be applied to this situation. This is done by rotating the take-up shaft and tensioning the slack. For these reasons, the amount of donor sheet pulled out for each image formation differs slightly, and if the feeding timing of the receiver sheet is uniquely set,
There is a slight shift each time an image is formed, and the positional accuracy of the image on the receiver sheet becomes extremely poor.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an image forming apparatus with high positional accuracy of an image on a receiver sheet.

(d) Means for Solving the Problems In this invention, a donor sheet wound around a supply shaft is pulled out and exposed, and then the donor sheet is conveyed and the latent image formed by the exposure is transferred to a pressure roller. and sent it,
In an image forming apparatus, a timing roller feeds a receiver sheet to a pressure roller in synchronization with the latent image, and development is performed by applying pressure with the pressure roller in a state where the latent image and the receiver sheet are overlapped. , a donor sheet withdrawal amount detection means for detecting the amount of withdrawal of the donor sheet 1 from the supply shaft; and a donor sheet withdrawal amount detection means for detecting the amount of withdrawal of the donor sheet from the supply shaft; The present invention is characterized in that a timing control means for controlling timing is provided.

(e) Operation FIG. 1 is a block diagram of the present invention. The donor sheet D wound around the supply shaft 102 is conveyed through an image forming path that includes an exposure position, a pressure roller, etc., and is wound onto a take-up shaft 103. On the other hand, the receiving sheet R is fed by the timing roller 106 to the pressure roller 105 in synchronization with the latent image formed by the exposure of the donor sheet D. In multi-image formation, the donor sheets are exposed to light one after another with a fixed interval between images, and the donor sheets are sequentially conveyed to expose the latent image formed by exposure first. When the images reach the pressure roller, development is performed one after another.

First, when exposure is performed at the exposure position (the tip is point PL), the supply shaft 102 is freed and the take-up shaft 103 (or other rollers or special rollers for pulling out the donor sheet D, etc.) Rotate and pull out the unexposed portion of the donor sheet D. At this time, the donor sheet withdrawal amount detection stage 101 accurately detects the two withdrawal amounts of the donor sheet D. Based on the detection result of the withdrawal amount,
Timing control means 100 controls the timing at which the timing roller 106 starts driving.

Therefore, even if you stop withdrawing Donacy 1-D,
The supply shaft rotates extra due to inertia. The donor sheet draw-out amount detection means 101 accurately detects the excess feed (slack) at that time, and the time required for the leading edge of the latent image to reach the pressure contact point P2 of the pressure roller, which varies slightly each time image is formed, is detected accurately. The drive start timing of the timing roller 106 is controlled by calculation.

Specifically, the pressure roller 10 is now moved from the exposure position tip P1.
If the distance of the conveyance path to the pressure contact point P2 of No. 5 is l, then the distance that the leading edge d1 of the latent image on the donor sheet reaches the pressure contact point P2 is also ρ. When the supply shaft 102 is freed and the donor sheath 1-D is pulled out, and the withdrawal is stopped, the supply shaft 1
Due to the inertial force of 02, the donor sheet D is extended out excessively and becomes slack, resulting in the shape shown by the two-dot chain line in the figure. The excess amount of loosening of this donor seam D is assumed to be α. Thereafter, in order to tighten the excess slack α, the winding shaft 103 is rotated to wind up the excess. This extra amount α is a variable that differs each time. Therefore, the distance for the latent image leading edge d1 to reach the pressure contact point P2 is actually βα, which is the amount by which the donor sheet D is pulled out, and differs for each image formation. Therefore, the time TI1 for the latent image tip d1 to reach the pressure contact point P2 is:
If the conveyance speed of donor sheet D is 1, then T. One (βα
)/■1, and this Tゎ also changes every time an image is formed. On the other hand, if the conveyance speed of the receiver sheet R is V2 and the distance from the timing roller 106 to the pressure contact point P2 is aR, then the time TR for the receiver sheet R stopped by the timing roller to reach the pressure contact point 2 is TR - It is constant at R/V2. Accordingly, the timing at which the timing roller 106 starts driving is the time T from the start of bowing of the donor sheet D. - This can be done after TR. Therefore, when the amount of donor sheet D is pulled out is large, this is because the excess amount α corresponding to the slack is large, and (2-α) becomes small, and the time T for the tip end d1 of the latent image to reach the pressure contact point P2,
is small and will soon reach pressure contact point P2, so time T. -TR (TR is constant) becomes smaller, i.e.
To speed up the timing at which the timing roller 106 starts driving. Conversely, when the amount of pull-out of the donor sheet D is small, this is because the excess amount α corresponding to the slack is small, and (lα) becomes large, and the time T for the tip end d1 of the latent image to reach the pressure contact point P2,
is large, the time TDTR (TR is constant) is large, and it takes time to reach the pressure contact point P2, which delays the timing at which the timing roller 106 starts driving.

As described above, since the timing control means controls the timing of starting driving of the timing roller according to the amount of withdrawal of the donor sheet, it is possible to improve the positional accuracy of the image developed on the receiver sheet.

(f) Embodiment FIG. 5 is a schematic diagram of an image forming apparatus according to an embodiment of the present invention. This image forming apparatus is an image forming apparatus to which the present invention is applied to the image forming apparatus shown in FIG. 6. Identical parts are given the same numbers, and details will be explained except for those already explained.

At the top of the image forming apparatus main body 1, a semiconductor laser 32 on the right side, an encoder 33, a motor 34, a triangular mirror 35,
An optical device 3 including a liquid crystal screen 36, a lamp 37, a filter 38, a left mirror 39, etc. is provided. The donor sheet 51 is wound around a supply shaft 53 and stored in the box 5, is conveyed along a conveyance path, and is wound onto a take-up shaft 54. A detection roller 11 is located at a turn-back position on the conveyance path near the outlet for donor sheet 51.
A rotary encoder 10 is disposed in contact with the back surface (uncoated surface) of the detector roller 11 and detects the amount of rotation of the detector roller coaxially with the detector roller 11 (donor sheet withdrawal amount detection means of this embodiment). is installed. Thereafter, an exposure plate 60, a bath roller 61, and pressure rollers 63 and 64 are arranged along the conveyance path of the donor sea +-.

A cassette 40 is disposed at the lower right side.
A receiver sheet 41 is housed inside. A feeding roller 47 and a timing roller 48 are arranged on the conveyance path of the receiver sheet 41 from the cassette 40 to the pressure developing section 6. A glossing device 7 is installed on the left side of the pressure developing section 6.
A paper ejection roller 81 is provided on the left side of the paper ejection roller 81, and a paper ejection section 8 is provided on the upper part of the main body 1.

Next, the image forming operation will be explained.

The light beam oscillated by the semiconductor laser 32 is reflected by a triangular mirror 35 attached to the shaft of the motor 34 and is reflected onto the liquid crystal screen 36.
is irradiated. The liquid crystal screen 36 has three screens, and red, green, and blue information is irradiated and written on each screen. Red, green, and blue lights are irradiated from the lamp 37 through the film 38 onto the liquid crystal screen 36 on which red, green, and blue information is written and are reflected. The red, green, and blue reflected lights are reflected by the mirror 39 and irradiated onto the donor sheet 51 of the exposure plate 60 for exposure. At this time, the rotation of the supply shaft 53 is made free and the bumper roller 61 is moved in the direction of arrow A to pull out the donor sheet. Even if the bath roller is stopped and the withdrawal is stopped, the supply shaft 53 does not stop immediately due to its inertia, and some of the donor sheet 51
I end up paying out too much. Since the excess slackens, the winding shaft 54 is rotated to wind it up a little, and the donor sheath 1/51 is brought into tension. In this way, the amount of pull-out of the donor sheet 51, which differs slightly each time an image is formed, is detected when the donor sheet 51 is brought into contact with the detection roller 11 at the folding position and is conveyed. Since the surface of the detection roller 11 is made of a material with high frictional resistance (rubber in this embodiment), it rotates with the movement of the donor sheet 51, has a structure with low inertia, and is installed at a folding position. Therefore, the movement of the donor sheet 51 can be accurately followed without slipping. Therefore, by detecting the amount of rotation of the detection roller 11 using the rotary encoder 12, the amount of withdrawal of the donor sheet can be accurately detected.

When the exposure is completed, the take-up shaft 54 is rotated to move the bath roller 61 in the direction of arrow B, and the latent image portion is transferred to the pressure developing section 6.
transport to. On the other hand, the receipt number 41 is cassette number 4.
The sheets are fed out one by one from zero, conveyed by a feeding roller 47, and temporarily stopped at a timing roller 48 to wait. The timing roller 48 starts driving at a timing set based on the amount of withdrawal detected by the donor sheet withdrawal amount detection means, and feeds the receiver 1 to the pressure rollers 63 and 64. This ensures that the image is always formed at the correct location on the recipient.

The donor sheet 51 and the receiver sheet 41 are passed between pressure rollers 63 and 64 in an overlapping state to be developed under pressure. The donor sheet 51 that has been used after pressure development is wound onto the winding shaft 54, and is rolled up into the receiver sheet 4.
1 is glossing device 7 and 13? After being processed, the sheet is conveyed from bottom to top by the discharge roller 81 and discharged to the paper discharge section 8 .

FIG. 4 is a diagram illustrating the withdrawal amount of the donor seam 1 in the image forming apparatus. The same figure (A) shows the state during exposure, in which the donor sheet 51 wound around the supply shaft 53 passes through the detection roller 11, the exposure position Pll to P1, the bottom roller 61, and the pressure rollers 63 and 64. and is wound onto the winding shaft 54. Banfarora 61 is BH
It is located at P. Assuming that the point on the donor sheet 51 currently located at Pl+ is d1, the point d becomes the leading edge of the latent image formed by exposure. The point on the donor sheet of the pressure contact point P2 of the pressure rollers 63 and 64 is d2, and the tip of the latent image dI
Let L be the distance from the latent image tip d1 to the pressure contact point P2 (same as d2 in this case) when fJ<P1I. Next, in the same figure (B), after freeing the rotation of the supply shaft 53 and moving the hasher roller 61 in the eight directions of the arrow and pulling out the donor seams 1 and 51 from the supply shaft 53, the hasher sofa roller 61 is moved at BP in the figure. This shows a state 14 in which the drawing is stopped and the withdrawal is stopped. The supply shaft 53 rotates due to inertia and feeds out an extra amount α of the donor sheet, causing it to become loose. At this time, d1 is moving as shown in the figure, but the distance I between d and pressure contact point P2 (same as d2 in this case) remains unchanged. However, U7 cannot continue exposing the donor sheet 51 in its loosened state, so fix the supply shaft 53 and slightly rotate the take-up shaft 54 to remove the donor sheet 5.
1 is applied with tension, resulting in the state shown in FIG. 1 (C). At this time, d1 and d2 have moved toward the winding shaft 54 by α as shown in the figure, and d2 has passed through the press contact point P2 by α. Then, the distance between the latent image tip d1 and the pressure contact point P2 is shortened by α, and becomes L - α. Therefore, the distance between the tip d1 of the latent image and the pressure contact point P2 varies depending on α,
The amount of the donor sheet 51 being pulled out from the supply shaft 53 is detected by the detection roller 11, and based on this detection result, the timing to start driving the timing roller is determined, and the image is transferred to an accurate position on the receipt sheet. can.

15 FIG. 3 is a block diagram of a part of the control section of the image forming apparatus.

A ROM 91 and a RAM 92 are connected to the CPU 90, which drives a main motor drive circuit 94 that drives a main motor 95, a donor sheet withdrawal amount detection means 96, a control circuit 97, and a bath roller 61 via an I/093. A roller drive circuit 99 for driving the roller and a timing roller drive circuit 98 for driving the timing roller 48 are connected. The control circuit 97 includes a clutch CI that connects the rotational force of the main motor to the supply shaft 53, a clutch C2 that connects the rotational force of the main motor to the winding shaft 54, and a pressure roller 6.
A clutch C3 that connects the rotational force of the main motor is connected to the clutch C3.

The CPU 90 controls the entire image forming apparatus, and the ROM 9
1 has a control program written in advance. RAM
92 is assigned a timer, counter, and other working areas. The CPU 90 reads out the control program and outputs signals to the main motor drive circuit 94, control circuit 97, roller roller drive circuit 99, timing crawler drive circuit 98, etc. via the I/093 to perform image forming operations. go. For example, when a drive signal for the roller roller 61 is output to the drive circuit 99 of the roller roller 61, and the roller roller 61 is driven and the donor sheet is pulled out,
A donor sheet withdrawal amount detection means 96 detects the withdrawal amount.

The CPU 90 takes in the detection data, reads out the control program from the ROM 91 or RAM 92, determines the timing to start driving the timing roller 48, and outputs a drive signal to the timing roller drive circuit 98. As a result, the timing of feeding a different receipt sheet each time an image is formed is controlled, and the position of the image on the receipt sheet is made accurate.

FIG. 2 is a flowchart of a control operation for feeding timing of receiving sheets in the case of multi-image formation in the same image forming apparatus.

When the power is turned on and the initial operations of each part are performed (
n1), waits for a print request from the postcomputer. When a printing request is made (I]2), an image is formed on the liquid crystal screen according to the image data sent from the 17 boss 1 computer (n3). When writing to the three images of red, green, and blue is completed (n4), an exposure step is performed (n5). The supply shaft is made free (r+6), and the counter N is reset to start I (n7) (the counter I of the withdrawal amount detection means is integrated into the RAMO counter N area).

Start moving the Hafa roller in the eight directions of the arrows in FIG. 5 (n8). When the hash sofa roller reaches position 13P in Fig. 4 (n9), the drive of the haw sofa roller is stopped (
nlo). At this time, the supply shaft rotates due to inertia and feeds out an extra toner sheet, causing the donor sheet 1 to slacken. At this time, the CPU 90 counts the donor seal by counting N.
The pull-out tail is determined and the timing to start driving the timing roller is generated (ni1). Turn the supply shaft (n12), rotate the take-up shaft (nl3), and tension the loosened donor sheet (nl4.). Thereafter, the winding shaft is stopped (nl5) and the Hanofa roller starts moving in the direction of arrow B in FIG. 5 (r+16). The timing roller is driven by the quimming (nl7) to feed the receiver sheet. The latent image on the donor sheet and the receiver sheet are overlapped and a pressure development process is performed using a pressure roller (n18), and the process returns to n5 to perform the next image forming operation.

In the above configuration, nll and nl7 correspond to timing control means.

In this embodiment, a detection roller and a rotary encoder were used as means for detecting the amount of donor sheath 1 pulled out, but any other means may be used as long as it can accurately detect the amount of withdrawal, including the slack of the donor sheath 1. No problem.

(g) Effects of the Invention According to the present invention, when feeding a receiver sheet in synchronization with the latent image formed on the donor sheet by exposure, the driving start timing of the timing roller is adjusted. , and is controlled according to the withdrawal amount of donor sea 1. Therefore, when the supply shaft is freed after exposure and the unexposed part of the donor seam 1 is pulled out, the amount of excess drawn out due to the haze of the supply 1 9 shaft after the withdrawal is stopped is also taken into account as the amount of withdrawal. Therefore, the latent image and the Recchier sheet are accurately aligned during pressure development, and it is possible to improve the positional accuracy of the image on the Recchifer sheet.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the present invention. FIG. 2 is a flowchart of the control operation for the feeding timing of receiver sheets in the case of multi-image formation in the image forming apparatus according to the embodiment of the present invention. FIG. 3 is a block diagram of a part of the control section of the image forming apparatus. FIG. 4 is a diagram illustrating the amount of donor sheet pulled out in the image forming apparatus. FIG. 5 is a schematic configuration diagram of the image forming apparatus. FIG. 6 is a schematic configuration diagram of a conventional image forming apparatus. 11-detection roller, 4 1-receiver sheet, 9n timing roller, donor sheet, supply shaft, take-up shaft, bumper roller, 66-pressure roller,

Claims (1)

[Claims] (1) After pulling out the donor sheet wound around the supply shaft and exposing it to light, the donor sheet is conveyed and the latent image formed by the exposure is sent to the pressure roller, and the timing is adjusted to the latent image. , an image forming apparatus in which a timing roller feeds a receiver sheet to a pressure roller, and the latent image and the receiver sheet are overlapped with each other, and the pressure roller applies pressure to develop the image. donor sheet withdrawal amount detection means for detecting the withdrawal amount of the donor sheet; and timing control means for controlling the timing of starting driving of the timing roller according to the donor sheet withdrawal amount detected by the donor sheet withdrawal amount detection means. An image forming apparatus characterized by: