JPH03195260A - Optical printer - Google Patents

Abstract

PURPOSE:To surely prevent production of banding at both front and rear edges by using a ridge exposure means so as to expose a ridge erasure light to both the front and rear edges in the carrier direction of a recording medium. CONSTITUTION:In order to prevent production of banding at a tip of a recording film P, when a tip of the recording film P is located at a downstream roller 23, a strobo light source is flashed and let the width of an exposure area between both rollers 22, 23 be X, then the ridge is erased by the strobo light source 26 for a range of Xmm from the starting point of the position of l-S1. Similarly, the position by S1mm from the rear ridge of the recording film P is takes as a start point and the range of Xmm from the point is subject to ridge erasure.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an optical printer that irradiates a photosensitive recording medium with light based on image data; ia +- forms an image on the recording medium.

The conventional technology is a type of optical printer (7) for photosensitive recording media.
An optical printer is known in which image exposure is performed using a laser beam. In this type of optical printer, the image is recorded by modulating the laser light according to the image data and irradiating the modulated laser light onto a photosensitive recording medium such as a silver halide film. I try to reproduce it in the medium. Writing an image onto a recording medium is carried out using a sub-scanning drum and two pressurized drums.
This is performed in a sub-scanning section having two nip rollers.

Problems to be Solved by the Invention When an image is reproduced using such an optical printer, banding may occur on the recording medium. Banding and stone formation are phenomena in which white lines or thin lines are formed on a recording medium, and they often occur particularly at predetermined positions between the leading edge and trailing edge of the recording medium. This is not preferable from the viewpoint of image reproduction. This phenomenon is thought to be caused by the nip roller when it bites the leading edge of the recording medium in the sub-scanning section and when it separates from the trailing edge.

In order to prevent banding, since this phenomenon occurs due to shock when the nip rollers are caught, a transparent part has been installed in the area between the two nip rollers that is irradiated with laser light. Attempts have been made to prevent the occurrence of the shock, but the transmittance of light when it passes through the transparent system changes, causing distortion in the image.

The present invention has been made in view of the above-mentioned problems of the prior art, and it is an object of the present invention to remove banding that occurs on a recording medium to reproduce a good-looking image.

Means for Solving the Problems In order to achieve the object described in item 1, the optical printer of the present invention conveys a photosensitive recording medium using a sub-scanning drum and two nip rollers that are in pressure contact with the sub-scanning drum. An optical printer that performs image exposure on a photosensitive recording medium between nip rollers, comprising: an optical module that performs image exposure by optically scanning the recording medium; and an optical module that exposes an edge of the recording medium in the conveying direction with edge-erasing light. and edge exposure means.

An image is written on the photosensitive recording medium by the light from the optical module, and the front and rear edges of the recording medium in the transport direction are exposed to edge erasing light by the edge exposure means, so that banding in these areas is eliminated. occurrence is reliably prevented.

EXAMPLE Hereinafter, the present invention will be described in detail with reference to the drawings showing an example of the present invention.

FIG. 1 is a schematic diagram showing the entire internal structure of an optical printer according to an embodiment of the present invention. A sub-scanning drum 11 is rotatably mounted in a housing 10 of the printer. is rotationally driven by a motor (not shown). Two nip rollers 12 and 13 are in pressure contact with the sub-scanning drum 11, parallel to the rotation center of the sub-scanning drum 1 and spaced apart from each other by a predetermined distance. Both ends of these two nip rollers 12 and 13 are rotatably supported by bearing members (not shown), and the sub-scanning drum 1
1. A pressing force is applied against.

The photosensitive recording film is housed in the paper feed section 14,
The sub-scanning section 1 consists of a sub-scanning drum 11 and a nip roller], 2.13, from which the sheets are fed out one by one.
5. This conveyance is performed by a pair of conveyance rollers 16 provided adjacent to the paper feed section 14.

Images are written on the recording film using a laser beam from an optical module, that is, a laser beam unit 17. The recording film is optically scanned and exposed to the optical module 17 by a laser beam modulated according to image data sent from a control section (not shown). The recording film on which the image has been written by the sub-scanning section 15 is conveyed through a guide path 18 to a developing device (not shown), and is developed there.

A guide plate 20 is installed between the sub-scanning section 15 and the pair of transport rollers 1-6, and an edge exposure device 21 is installed on the guide plate 20. As shown in an enlarged view in FIG. It is lightly pressed. As shown in FIGS. 3(A) and 3(B), these rollers 22, 23 are rotatably supported by bearing parts 24 at both ends, and are supported by spring parts (not shown) attached to these bearings 24. Accordingly, the rollers 22 and 23 have guide portions + (20).
The elastic force directed toward the two sides is energized.

A cover 25 is provided on one side of the rollers 22 and 23, and a strobe light source 26 is assembled into the cover 25. The cover 25 prevents the light from the light source 26 from leaking outside the cover 25, and regulates the exposure area in the transport direction and width direction of the recording film. The width of the exposure area is set to be slightly larger than the width of the recording film.

The leading edge or trailing edge of the recording film fed out from the paper feed unit 14 and conveyed along the guide plate 20 by the pair of conveying rollers 6 is connected to the two position detection rollers 22 and 23.
In order to detect that the position of the roller 22 located on the 1-1 flow side in the conveying direction has been reached, the roller 22 shown in FIGS.
As shown in FIG. 2, an actuator 27 that functions as a photointerlator is fixed to the bearing member 24. FIG. 3A shows a state in which the recording film P has not yet reached the position of the roller 22, and at this time, the two rollers 22 and 23 are in direct contact with the guide plate 20. The recording film P is continuously conveyed, and as shown in FIG. 3(B), the leading end of the recording film P touches the roller 2.
When the recording film P reaches position 2, the recording film P is sandwiched between the roller 22 and the kite board 20, so the roller 22
is separated from the guide plate 20, and the bearing portion 24 is tilted as shown. In order to detect that the leading end of the recording film P is bitten by the roller 22 due to this inclination,
As shown in FIG. 3, a photo sensor 28 having a light emitting element and a light receiving element is provided. Biting is detected when the actuator 27 blocks the photosensor 28.

Assuming that the distance between the contact points of the two nip rollers 22 and 23 with the sub-scanning drum 11 is L as shown in FIG.
Banding was observed to occur at a position 2/L from the leading edge of the recording film and at a position 2/L before the trailing edge. Therefore, if the strobe light source 26 is used to expose a range of ±3 mm around this position between the rollers 22 and 23, banding will not occur on the developed recording film.

Therefore, in order to prevent banding from occurring at the leading edge of the recording film P, the timing at which the strobe light source 26 is turned on is shown in FIG. 4(A). In this figure, the strobe light source is turned on when the leading edge of the recording film P reaches the position of the downstream roller 23, and the width dimension of the exposure area between both rollers 22 and 23 is
Then, in order to expose a range of ±3 mm as described above, X must be set larger than 6 mm.

Moreover, if the distance between the centers of both rollers 22 and 23 is β,
The distances S1 and S2 shown in FIG. 4 are 51-
(ρ+X)/2, which becomes 52(n-X)/2. And these W1 separation values are S 1 < (L/2
) -3mm52> (L/2) +3mm.

In the above case, the distance from the leading edge of the recording film P to Ω-81
The strobe light source 26 erases the edges in a range of X mm starting from the position of . Similarly,
Starting from a position 81 mn from the rear end of the recording film P, an area of X mm from this point is erased. however,
Instead of this method, as shown in FIG. 3(B), exposure may be performed when the leading edge of the recording film reaches the edge of the exposure area. In this case, the width dimension of the exposure area, Y, must be set to Y > (L/2) + 3 mm. is irradiated.

In the illustrated optical printer, a positive film is used to reproduce a positive image. There are two printing formats, one with white edges and one with black edges, which can be automatically switched by a signal from the control unit by an operator operating a key.

FIG. 5 is a flowchart showing the operating procedure of the illustrated optical printer. If it is determined in step 30 that the operator has turned on the print switch in order to form an image on the recording film P, step 31 and paper feed section 1
The recording film P is fed out from inside the recording film 4, and is further conveyed by the conveyance roller 16. From the host computer side, a voter instruction, ie, an edge instruction, comes in step 32. This instruction is white, i.e. step 3
If it is determined No in step 2, the edge exposure device 21 does not operate for the fed recording film P, and the leading edge of the recording film P reaches a predetermined position in the sub-scanning section 15. If it is determined in step 33]0, in step 34, the recording film P is illuminated with laser light from the optical module 1-7.
14, an image is formed.

On the other hand, if YES is determined in step 32, it means that a command to make the edges black has been issued, and if the sensor 28 is turned on as the recording film P is transported (step 35) , the timer is turned on in step 36. This timer starts from the fourth time the sensor 28 turns on.
As shown in Figure (A), this is to count the time until the leading edge of the recording film P reaches the position of the roller 23 on the downstream side.If the end of the timer is detected in step 37, step 38 is performed. The strobe light source 26 is turned on. If it is determined in step 3 that the leading edge of the recording film P has reached the predetermined position of the sub-scanning section 15, as in step 33, an image is written in step 40.

Images are recorded on the recording film P while being fed in the conveyance direction, that is, in the sub-scanning direction, by the rotation of the sub-scanning drum 1. When the rear end of the recording film P passes the position of the roller 22 on the upstream side, Step 4], the sensor 28 is turned off, and immediately in step 42
・Robo light source 26 lights up. As a result, the trailing edge of the recording film P is exposed to edge erasing light by the edge exposure device 21. If it is determined in step 43 that writing of the image by the optical module 17 has been completed, the process returns to step 30 and waits for the next print command.

However, the area where the edge-erasing light was exposed by the strobe light source 26 will be re-attached to the optical module during the image writing process]
The laser beam from 7 is used to overwrite the image in black, and the density of a portion of the porter, that is, the front and rear edges, is set to be uniform.

In the illustrated embodiment, before an image is written on the recording film P, the edge exposure device 17 is used to expose the recording film P to strobe light, but after the optical module 17 has finished writing the image, the strobe light is exposed. You can do it like this. In that case, the edge exposure device 17 will be installed downstream of the sub-scanning section 15.

2 Effects of the Invention As described in -1-, according to the present invention, the banding that occurs at both the front and rear edges of the recording medium in the conveying direction is erased by light from the edge exposure means, and the banding is removed by the light from the edge exposure means. A reproduced image with good later appearance was formed on the recording medium.

[Brief explanation of drawings]

FIG. 1 is a schematic front view showing the internal structure of an embodiment of the optical printer of the present invention, FIG. 2 is an enlarged sectional view of the main part of FIG.
Figures 3(A) and 3(B) are schematic sectional views showing the operating state of the sensor for detecting the position of the recording medium, and Figure 4(A)
)(B) is a sectional view showing the dimensions of the exposure area by the edge exposure device, and FIG. 5 is a flowchart showing the operating procedure of the optical printer. DESCRIPTION OF SYMBOLS 11... Sub-scanning drum, 1-2. 13... Nip roller, 15... Sub-scanning part, 1-7... Optical module, 21... Edge exposure device.

Claims (1)

[Claims] An optical printer that performs image exposure on the photosensitive recording medium between the two nip rollers while conveying the photosensitive recording medium by a sub-scanning drum and two nip rollers that are in pressure contact with the sub-scanning drum, the recording medium being optically scanned. An optical printer comprising: an optical module that performs image exposure by performing image exposure; and an edge exposure unit that exposes an edge of the recording medium in the conveyance direction with edge erasing light.