JPH10333063A - Optical writing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To use a light quantity detecting sensor and an image write starting position detecting sensor in common for an optical writing device performing sub-scanning by the displacement of a scanning mirror in addition to main scanning by an optical chip. SOLUTION: This device turns on/off light radiated from a lamp 21 by an optical chip 31 being driven based on an image signal and performs sub-scanning on a printing paper 6 in the direction of an arrow Y or reverse direction by moving a scanning mirror 40 back and forth. In this case, light sensors 51, 52 arrange many light receiving elements corresponding to the optical chip 31 in the main scanning direction and are installed outside a plotting area. At the time of plotting and starting the rotation of the scanning mirror 40, light is detected by the light sensors 51, 52 and write starting position P2 or P2 ' is determined based on the detection timing. The light quantity of each optical chip is detected from the received light quantity of the light sensor 51 or 52 and compensation data for removing the irregularity of light quantity are calculated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical writing device, and more particularly, to an optical chip such as PLZT for turning on and off light based on an image signal and writing an image (latent image) on a photosensitive material. The present invention relates to an optical writing device.

[0002]

BACKGROUND OF THE INVENTION Generally, in order to form an image (latent image) on a photographic paper, a film, or an electrophotographic photoreceptor using a silver halide photosensitive material, light is emitted pixel by pixel using an optical shutter chip such as PLZT. Various optical writing devices that perform on / off control have been provided. In this type of optical writing device, a large number of optical shutter chips are arranged in a main scanning direction, and a photosensitive material is moved in a sub-scanning direction orthogonal thereto to draw a two-dimensional image. However, it is difficult to precisely move the photosensitive material in the sub-scanning direction and speed.

Therefore, a method has been proposed in which, in addition to the main scanning by the optical shutter chip, the mirror is rotated and the light is sub-scanned. In this method, at the time of drawing, the photosensitive material only needs to be held in a stationary state, the accuracy of sub-scanning movement is not required at all, and the drawing speed of one sheet is improved.

However, this scanning method has a problem in that various optical sensors are required and the cost increases accordingly. That is, a sensor is required to detect the writing start position in the sub-scanning direction. Furthermore, since the light shutter chips have different light transmission characteristics and change over time (deterioration due to fatigue), a light amount detection sensor that samples data for light amount correction obtains a high-quality image. Is necessary for

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an optical writing device which can use the light amount detection sensor as an image writing start position detection sensor.

In order to achieve the above object, an optical writing apparatus according to the present invention is an optical writing apparatus that performs a sub-scan by a scanning mirror in addition to a main scan by an optical chip.
An optical sensor in which a large number of light receiving elements are arranged in the main scanning direction in correspondence with the optical chip is provided outside a drawing area where sub scanning is performed by a scanning mirror.

In the present invention, a large number of optical chips arranged in the main scanning direction are turned on and off to perform main scanning of an image one line at a time, and sub-scanning is performed by displacing a scanning mirror, so that a stationary state is obtained. A two-dimensional image is formed on a certain light receiving surface. The optical sensor receives the light to be sub-scanned outside the drawing area, detects the light amount of each optical chip, and corrects the light amount of each optical chip based on the detected value.

If the creation and correction processing of the light quantity correction data is performed in parallel with the drawing, it is executed between the timing when the optical sensor receives light outside the drawing area and the timing when the image writing is started. Alternatively, a correction data creation mode independent of drawing may be set separately. This mode of creating the light quantity correction data is performed when the power of the printer is turned on or every predetermined number of prints. Alternatively, it is executed at an appropriate time by a serviceman's operation.

On the other hand, when the optical sensor receives the scanning light from the scanning mirror, an image writing start timing is set by a timer or the like, and the ON / OFF control (ON / OFF) of the optical chip is performed from the set timing (writing start position). Image writing) is performed. Regarding the image writing position control, it is sufficient that at least one light receiving element receives light.

That is, according to the present invention, the photosensors in which the light receiving elements are arranged in the main scanning direction in correspondence with the optical chips are provided outside the drawing area to be sub-scanned by the scanning mirror.
The optical sensor for correcting the light amount and the optical sensor for detecting the image writing start position in the sub-scanning direction can be used in common, and the number of optical sensors to be installed can be reduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an optical writing device according to the present invention will be described below with reference to the accompanying drawings.

(Color Printer) FIG. 1 shows a color printer 1 and a printer processor 10 for photographic printing on which an optical writing head 20 according to an embodiment of the present invention is mounted.
This color printer 1 has an optical writing head 20
And a photographic paper delivery cartridge 5 containing a photographic paper 6 using a silver halide photosensitive material in a roll shape is mounted on the left side of the main body 2 and a photographic paper take-up cartridge 7 is mounted on the right side. It is installed. The printing paper 6 is introduced into the main body 2 from the cartridge 5, and after the image (latent image) is drawn by the optical writing head 20, the printing paper 6 is wound into the cartridge 7.

The printer processor 10 processes development, drying, cutting, and the like of the exposed photographic paper 6. The cartridge 7 wound with the exposed photographic paper 6 is
And is attached to the sending unit 11 of the processor 10. Here, the exposed photographic paper 6 is pulled out of the cartridge 7 and developed while being transported in the processor 10.
After being dried and cut to a predetermined length, it is discharged outside the machine.

(Optical writing head) FIG.
2 shows an optical writing head 20 for full color mounted on the optical recording head. The optical writing head 20 is for writing a full-color image on the photographic paper 6, and generally includes a halogen lamp 21, a heat-insulating filter 22, an RGB filter 25, an optical fiber array 26, an optical shutter module 30, and an imaging lens 35. , A scanning mirror 40, an imaging lens 45, and optical sensors 51 and 52. The full-color drawing is a method in which R, G, and B images separated into three primary colors are superimposed and reproduced, and is well known in itself.

The RGB filter 25 is provided for each of R, R, and B components formed by an optical shutter chip 31 and a scanning mirror 40 described below.
It is driven to rotate in synchronization with the writing of the G and B images, and changes the passing color for each sub-scan. Optical fiber array 26
Is composed of a number of optical fibers, and one end 26a is bundled and faces the RGB filter 25. The other ends 26b are arranged in the main scanning direction indicated by the arrow X, and emit light in a line.

The optical shutter module 30 has a slit-shaped opening in a ceramic substrate or a PLZT
Is provided, and a driver IC 32 is provided side by side with the optical shutter chip 31. In each of the optical shutter chips 31, only those corresponding to pixels to be drawn by the driver IC 32 are driven (turned on). Further, polarizing plates 33 and 34 are provided before and after the optical shutter module 30.

As is well known, PLZT is a light-transmitting ceramic having an electro-optic effect having a large Kerr constant, and light linearly polarized by the polarizing plate 33 is supplied to the optical shutter chip 31 with a voltage. The rotation of the polarization plane is caused by the on / off of the electric field generated by the application, and the light emitted from another polarizing plate 34 is turned on / off. Polarizing plate 3
The light emitted from 4 passes through the imaging lens 35 and is guided to the scanning mirror 40.

The scanning mirror 40 is installed so as to be able to reciprocate at a predetermined angle and speed by a motor (not shown) with the support shaft 41 as a fulcrum. As shown in FIG. 3, when the scanning mirror 40 rotates in the direction of the arrow y, the light transmitted through the imaging lens 35 is scanned in the sub-scanning direction indicated by the arrow Y, and is stopped via another imaging lens 45. Is exposed on the photographic printing paper 6 in the above. When the scanning mirror 40 rotates in the direction opposite to the arrow y, the light is sub-scanned in the direction opposite to the arrow Y.

The light sensors 51 and 52 have a large number of light receiving elements arranged in the main scanning direction X in correspondence with the optical shutter chip 31, and have positions P ₁ and P ₁ ′ outside the drawing area P ₂ -P ₂ ′. It was installed in. The optical sensor 51 receives light at a position P ₁ when the light is scanned in the direction of the arrow Y, and the optical sensor 52 receives light at a position P ₁ ′ when the light is scanned in the direction opposite to the arrow Y.

(Image Writing and Light Amount Correction, First Operation Mode) In the first operation mode, data creation for light amount correction is processed independently of image writing. That is, processing is performed when the power of the printer 1 is turned on, every time a predetermined number of images are formed, or when a service person inputs execution of the light quantity correction data creation mode. In this case, all of the light shutter elements 31 while applying a predetermined voltage, the lamp 21 lit by rotating the RGB filter 25, an optical sensor 51 or 5 at a position P ₁ or P ₁ '
2, the light amount of each of R, G, and B is measured by sampling the detection value of each light receiving element, and the CPU calculates correction data for equalizing the transmitted light amount of each optical shutter chip 31. Thereafter, the image signal is corrected by referring to the correction data at the time of printing, and the light shutter chip 3
1 is driven.

When writing an image on the photographic paper 6, when the scanning mirror 40 is rotated in the direction of the arrow y, when the optical sensor 51 receives the scanning light, the voltage application to the optical shutter chip 31 is temporarily turned off, and the timer is turned off. Counts the time between P _{1 and} P ₁ , on / off control of the optical shutter chip 31 is started based on the image signal. Similarly, when the scanning mirror 40 rotates in the direction opposite to the arrow y, the position P ₂ ′ is determined based on the light receiving signal of the optical sensor 52 at the position P ₁ ′.
, The on / off control of the optical shutter chip 31 is started.

In reproducing a full-color image as in this embodiment, R, R
The G and B images are scanned, and one full-color image is drawn by a total of three rotations. When writing an image in the first operation mode, it is not necessary that all the light receiving elements of the optical sensors 51 and 52 receive light, and it is sufficient that at least one light receiving element receives light.

(Image Writing and Light Amount Correction, Second Operation Mode) In the second operation mode, light amount correction data is created in parallel with image writing, and correction processing is executed. R,
Assuming that images are written in the order of G and B, first, as shown in FIG. 4, the scanning mirror 40 is rotated in the direction of arrow y, the optical shutter chip 31 is turned on, and the optical sensor 51 is irradiated with R light. The light receiving of R light when passed between P ₁ -P ₂ starts scanning of the R image (see FIG. 5). During the period between P _{1 and} P _2, the optical shutter chip 31 is maintained in the off state, and during that time, the light amount correction data of the R light is calculated from the amount of light received at the position P ₁ , and the R light amount between the P _{2 and} P ₂ ′ is calculated. Feedback to image scanning.

The scanning of the R image is completed at the position P ₂ ′, and when the scanning mirror 40 is rotated to the angle for irradiating the position P ₁ ′, the rotation direction is switched in the direction opposite to the arrow y, and the light The shutter chip 31 is turned on and the light sensor 52 is irradiated with the G light (see FIG. 6). Then, the scanning of the G image is started when a period between P ₁ ′ and P ₂ ′ has elapsed from the reception of the G light (see FIG. 7). During the period P ₁ ′ −P ₂ ′, the light shutter chip 31 is kept in the off state, and during that time, the light amount correction data of the G light is calculated from the light reception amount at the position P ₁ ′,
This is fed back to the scanning of the G image between P ₂ ′ and P ₂ .

The scanning of the G image ends at the position P ₂ , and when the scanning mirror 40 rotates to the angle for irradiating the position P ₁ , the rotating direction is switched in the direction of the arrow y, and at the same time, the optical shutter chip 31 is turned on. Then, the light sensor 51 is irradiated with the B light (see FIG. 8). Hereinafter, as in the scanning of the R image, P
Calculates the light quantity correction data B light between _{1 -P 2, P 2 -P 2} '
It feeds back to the scanning of the B image between (see FIG. 9).

When the scanning of the B image is completed, the printing paper 6 is
To move the pitch (one image forming area) and draw the next image, the scanning mirror 40 is rotated in the direction opposite to the arrow y to scan the R image, and the G image and the B image are sequentially scanned. Perform a scan.

(Other Embodiments) The optical writing device according to the present invention is not limited to the above embodiment, but can be variously modified within the scope of the invention.

In particular, in the above embodiment, a color printer for forming a full-color image has been described, but a printer for forming a monochrome image may be used. As an optical chip, besides PLZT, LCS (Liquid Cryst
al Shutter), DMD (Deformable Device), and the like, and the configuration of the imaging optical system is arbitrary.
Further, an ND filter or a color correction filter may be provided before or after the heat insulating filter 22, or a slit may be interposed between the optical fiber array 26 and the polarizing plate 33.

Further, the present invention is applicable not only to an image writing apparatus for photographic paper using a silver halide photosensitive material but also to an image writing apparatus for a silver halide film or an electrophotographic photosensitive member or an image projection apparatus on a display. Applicable.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating a printer and a processor including an optical writing head according to an embodiment of the invention.

FIG. 2 is a perspective view showing the optical writing head.

FIG. 3 is an explanatory diagram illustrating an image writing operation in a first operation mode.

FIG. 4 is an explanatory diagram showing an image writing operation in a second operation mode.

FIG. 5 is an explanatory diagram showing an image writing operation in a second operation mode, and is a continuation of FIG. 4;

FIG. 6 is an explanatory view showing an image writing operation in the second operation mode, and is a continuation of FIG. 5;

FIG. 7 is an explanatory view showing an image writing operation in the second operation mode, and is a continuation of FIG. 6;

FIG. 8 is an explanatory diagram showing an image writing operation in the second operation mode, and is a continuation of FIG. 7;

9 is an explanatory diagram showing an image writing operation in the second operation mode, and is a continuation of FIG. 8;

[Explanation of symbols]

 Reference Signs List 6 photographic paper 20 optical writing head 21 halogen lamp 30 optical shutter module 31 optical shutter chip 32 driver IC 35, 45 imaging lens 40 scanning mirror 51, 52 optical sensor

Claims (1)

[Claims] 1. An optical shutter module comprising a number of optical chips arranged in a main scanning direction, each optical chip being turned on and off based on an image signal, and an illumination optical system for irradiating the optical shutter module with light. An imaging optical system that forms an image of light emitted from the optical shutter module on a light receiving surface; a scanning mirror that scans light emitted from the optical shutter module in a sub-scanning direction; An optical writing device, comprising: an optical sensor arranged in the main scanning direction corresponding to the optical chip and installed outside a drawing area of light to be sub-scanned by the scanning mirror.