JPH06337361A - Optical scanning mechanism - Google Patents

Abstract

PURPOSE:To simultaneously make exposure with three colors without making a rotary polygon mirror large in size. CONSTITUTION:Red, green and blue laser beams are made incident on the mirror face 12a of the rotary polygon mirror 12, each optical axis 1R, 1B and 1G is lying on the same plane 2 and made incident on a straight line which is parallel to the rotary center shaft 12b of the rotary polygon mirror 12. The optical axes 1R and 1B of red and blue laser beams are posisioned on both sides of the optical axis 1G of the green laser beam by forming an angle W, and they intersect on a point on photoreceptor material through the mirror face 12a. Scanning is carried out by rotating the rotary polygon mirror 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical scanning mechanism for scanning a light beam with a rotating polygon mirror.

[0002]

2. Description of the Related Art As a method for obtaining a color hard copy, there is an optical scanning method. For example, in an optical scanning method in which a silver salt sensitive material such as an instant color film is directly written using a laser beam of three colors, the laser beam can be narrowed down to a minute diameter, so that the resolution is high and each dot to be recorded is Since the density can be modulated, excellent reproducibility can be obtained even in an image having many halftones.

In order to record a color image with a laser beam of three colors, one of the laser beams of red, green and blue is used as a reference, and the optical axes of the laser beams of the other two colors are set on the optical axis. By making them coincide with each other, all the three-color laser beams can be made incident on the rotary polygon mirror with one optical axis. In this case, the laser beams of each color can be gathered at one point on the recording surface, and color image recording can be performed without color deviation.

There is also known a structure in which laser beams of three colors are made incident on a rotating polygonal mirror with different optical axes, and hitherto, the optical axis of each laser beam is the central axis of rotation of the rotating polygonal mirror. In the same plane that is substantially orthogonal to, the incident points of the laser beams are aligned on a straight line orthogonal to the central axis of rotation of the rotary polygon mirror on the mirror surface of the rotary polygon mirror. In this case, there are one in which each laser beam is incident on the rotary polygon mirror at different angles, and one in which each laser beam is incident on the rotary polygon mirror at the same angle (incident in parallel). The latter one Uses an imaging optical system to collect each laser beam at one point on the recording surface.

[0005]

However, in order to make the laser beams of three colors enter the rotary polygon mirror with a single optical axis,
Dichroic mirrors are indispensable, and high precision is required for aligning the optical axis of each laser beam, which is expensive. Furthermore, in the case where each laser beam is guided to a rotating polygon mirror with different optical axes and each laser beam is made incident on a straight line orthogonal to the rotation center axis of the rotating polygon mirror, movement of the mirror surface of the rotating polygon mirror Since the incident points of each laser beam are aligned in each direction, the time for all the laser beams to be incident on the same mirror surface is shortened, and the scanning range is narrower unless the mirror surface is made larger than when scanning a single laser beam. Become.

The present invention has been made in order to solve the above problems, and shifts the recording timing of each light beam when the light beam of a laser or the like is made incident on a plurality of rotary polygon mirrors to perform optical scanning. It is an object of the present invention to provide an optical scanning mechanism that can perform recording without a need, and can be downsized and reduced in cost.

[0007]

In order to achieve the above object, the present invention makes a plurality of light beams incident on the mirror surface of a rotary polygon mirror along the same plane parallel to the central axis of rotation of the rotary polygon mirror. Moreover, the incident positions of the light beams on the mirror surface are arranged on a straight line orthogonal to the central axis of rotation of the rotary polygon mirror. Further, in the invention according to claim 2, the plurality of light beams are on the same plane parallel to the rotation center axis of the rotating polygon mirror, and at different angles with respect to a plane orthogonal to the rotation center axis. It is configured to enter the rotating polygon mirror.

[0008]

According to the above construction, the respective light beams reflected by the rotary polygon mirror form different scanning planes,
Since the scanning positions of the light beams in each scanning plane are all the same, it is not necessary to shift the recording timing of each light beam. If each light beam is incident on the surface orthogonal to the rotation center axis of the rotating polygon mirror at a different angle so that each light beam converges at one point on the recording surface, recording with the rotating polygon mirror An optical system for deflecting the light beam in a direction orthogonal to the scanning surface is not required between the surface and the surface.

[0009]

FIG. 2 shows an example in which the present invention is applied to a heat development type silver salt color printer for producing an ID card. To the input terminals 10R, 10G, and 10B, the gradation data of the red image, the gradation data of the green image, and the gradation data of the blue image, which are captured by a scanner or the like and are written in the memory for each color for each dot, are set to 1 It is input for each scanning line and sent to the timing control circuit 11.

The rotary polygon mirror 12 is integrally provided with a shaft,
The rotary polygon mirror 12 is rotated by driving the motor 13. The controller 14 rotates the motor 13 at a constant rotation speed and inputs a signal synchronized with the rotation of the motor 13 to the timing control circuit 11. Timing control circuit 1
1 receives a signal from the controller 14, and the rotary polygon mirror 1
The gradation data for each color dot is sent to the optical modulator drivers 15R, 15G, 15B at the timing synchronized with the rotation of 2.

A He-Ne laser oscillator is used as the laser oscillator 16R and emits a red (wavelength 632.8 nm) laser beam. In addition, laser oscillators 16G, 16
An Ar ⁺ laser oscillator and a He-Cd oscillator are used for B, respectively, and emit green (wavelength 514.5 nm) and blue (wavelength 441.6 nm) laser beams.

The laser beams emitted from the laser oscillators 16R, 16G and 16B are ultrasonic light modulators 17R, 17G and
It is incident on 17B. Ultrasonic light modulators 17R, 17G,
As well known, 17B is composed of an acousto-optic modulator, a lens optical system, and the like, and the optical modulator driver 15R, 1B.
Driven by the modulation signals from 5G and 15B, the light amount of the laser beam passing through is increased or decreased for each color. Since the modulation signal corresponds to the gradation data for each color dot, as a result, the ultrasonic light modulators 17R, 17G, 17
The laser beam having passed through B is adjusted to have a light amount corresponding to the light and shade of each color dot. The laser beam whose amount of light is increased / decreased is transmitted to the ultrasonic light modulators 17R and 17R.
It is emitted as a parallel light flux from G and 17B.

The imaging lenses 18R, 18G and 18B are lenses for converging the diameter of the laser beam of the parallel light flux from the ultrasonic light modulators 17R, 17G and 17B, and are incident on the mirror surface 12a of the rotary polygon mirror 12. The diameter of the laser beam reflected from the mirror surface 12a is converged to the minimum on the main scanning line.

As shown in FIG. 1, the imaging lenses 18R,
Optical axis 1 of laser beam emitted from 18G, 18B
R, 1G and 1B are rotation center axes 12b of the rotary polygon mirror 12.
Is on the same plane 2 parallel to. The optical axes 1R and 1B of the red and blue laser beams are the optical axes 1R of the green laser beams.
It is inclined with respect to G at an inclination angle ω. With this tilt angle ω, the optical axes 1R of the red and blue laser beams,
Since 1B is set so as to intersect the optical axis 1G of the green laser beam on the recording surface at one point, on the mirror surface 12a of the rotary polygon mirror 12, the incident point of each laser beam is parallel to the rotation center axis 12b. They will line up in a straight line. And
By rotating the rotary polygon mirror 12 around the rotation center axis 12b, the laser beams of the three colors form individual scanning planes, but form one scanning line on the recording plane.

The rotary polygon mirror 12 has eight mirror surfaces 12a, and scans eight times in one rotation. Sensitive material 19 is drum 20
It is wrapped around the surface of and is placed on a cylindrical surface containing the main scanning line. The controller 14 drives the motor 21,
By rotating the drum 20, the photosensitive material 19 is sent in the sub-scanning direction in synchronization with the main scanning, and the image is exposed on the photosensitive material 19. The photosensitive material 19 is a heat-developable silver salt photosensitive material,
Cyan, magenta, and yellow are emitted corresponding to the green and blue laser beams.

Next, the operation of the above configuration will be described with an example of creating an ID card. The facial photograph is taken by a scanner or an electronic still photograph and stored in a memory. Further, necessary items such as name, company name, department, etc. are input to the computer, and a face photograph, name, etc. are combined as image data on a memory at a predetermined position of the ID card form.
This image data is gradation data for each color of red, green, and blue, and these gradation data are sent to the timing control circuit 11 for each scanning line.

The laser beams from the laser oscillators 16R, 16G and 16B are transmitted by the ultrasonic light modulator 17R. 17
It is incident on G and 17B.

The timing control circuit 11 includes a rotary polygon mirror 1.
When the recording point comes to a desired recording position at a timing matched with the rotation angle and the rotation speed of 2, the image data of each color of one scanning line is supplied to the optical modulator drivers 15R and 15R for each dot.
Start sending to G, 15B. At this time, gradation data for each color dot recorded at the same position is simultaneously transmitted. The ultrasonic light modulators 17R, 17G, and 17B increase or decrease the light amount of each laser beam according to the density of dots to be recorded at the recording point. Each laser beam thus modulated is emitted as a parallel light beam, and the imaging lenses 18R, 18
The beam diameter is narrowed by G and 18B, and is incident on the rotary polygon mirror 12.

The laser beams of the respective colors reflected by the rotary polygon mirror 12 are converged to one point by the business card-sized photosensitive material 19 wound around the drum, and are exposed with the light amount corresponding to each image data. As a result, cyan, magenta, and yellow latent images are formed on the dots. As the rotation of the rotary polygon mirror 12 progresses, the optical modulator drivers 15R, 15G,
Gradation data is input to each dot 15B one after another, the laser beam is struck by the mirror surface 12a, and a latent image is formed on the photosensitive material 19 by sequentially changing the light and shade of each dot.

At this time, the same plane where the optical axes of the three-color laser beams are parallel to the rotation center axis 12b of the rotary polygon mirror 12, and the optical axes 1R, 1G, and
1B is incident on one straight line parallel to the rotation center axis 12b of the rotary polygon mirror 12 at the mirror surface 12a, so that 3B is always 3
The color laser beams are incident on the mirror surface 12a at the same time, and main scanning can be used to fill the width direction of the mirror surface 12a.

In this way, one surface of the mirror surface 12a exposes one scanning line portion, the photosensitive material 19 is sent in synchronization with the main scanning, and the main scanning is performed one after another. A latent image is formed on the image. After all the exposure of the image is completed, the photoconductor 19 is thermally developed, and cyan, magenta, and yellow are colored, and a print in which a face photograph and characters such as name are combined is obtained. By setting the photoconductor according to the arc drawn by the recording point, it is possible to obtain a wider angle of view and higher image quality.

In the embodiments described above, the heat-developable silver salt sensitive material was used for the photoconductor, but it can be applied to photoconductors such as instant film and positive film. Although the gas laser is used as the light source for recording each color, a semiconductor laser may be used. When using a semiconductor laser, it is also possible to input a drive signal corresponding to image data to the light source itself to increase or decrease the light amount of laser light. The tilt angle ω of the optical axis of the laser beam is not necessarily required, and when ω = 0 (each optical axis is parallel), the beam reflected by the rotating polygon mirror is refracted by a prism or the like to be matched on the recording surface. Good.

[0023]

As described in detail above, according to the present invention, the optical axes of a plurality of light beams are on the same plane and are parallel to the rotation center axis of the rotary polygon mirror of the mirror surface of the rotary polygon mirror. Since it is arranged so as to be incident on one straight line, the mirror surface of the rotary polygon mirror can be effectively utilized in the rotation direction, and it becomes possible to simultaneously expose dots at the same position of each color without increasing the size.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a state of laser light incident on a rotary polygon mirror.

FIG. 2 is a schematic view of a heat developable silver salt photographic color printer embodying the present invention.

[Explanation of symbols]

 1R, 1G, 1G Optical axis 12 Rotating polygon mirror 12a Mirror surface 16R, 16G, 16B Laser oscillator 17R, 17G, 17B Ultrasonic light modulator 19 Sensitive material

Front page continued (72) Inventor Hiroyuki Uchiyama 3-13-45 Izumi, Asaka-shi, Saitama Fuji Photo Film Co., Ltd.

Claims (2)

[Claims] 1. An optical scanning mechanism in which a plurality of light beams are made incident on a rotating polygonal mirror, and a plurality of light beams are collected at one point on a recording surface to obtain one scanning line. The light beam is incident on the mirror surface of the rotating polygon mirror along the same plane parallel to the rotation center axis of the rotating polygon mirror, and the incident positions of the light beam on the mirror surface are aligned. Scanning mechanism. 2. The optical scanning mechanism according to claim 1, wherein the plurality of light beams are incident on the rotary polygon mirror at different angles with respect to a plane orthogonal to the rotation center axis of the rotary polygon mirror. .