JPS59164568A - Reproducing device of color picture - Google Patents

Abstract

PURPOSE:To obtain a reproduced color picture with high quality by modulating a beam so that each dot is not overlapped to one color picture element to be reproduced. CONSTITUTION:If one picture element to be reproduced is lXl, the diameter of a laser beam scanning on a photosensitive drum is set up to l/2, laser beam scanning executes l/2 pitch scanning in both main scanning X and sub-scanning Y and the one picuture element is expressed by 4 dots. Each color out of yellow (Y), magenta (M), cyan (S), and black (B) is scanned on every other dot in the main scanning X and on every other line in the sub-scanning Y and only 1/4 area of one picture element is scanned. Namely each color data are scanned only by 1/4 area of an output picture element and prevented from being overlapped with each other, so that color reproducibility at the output of many colors to the same picture element can be improved. Consequently, a reproduced color picture with high quality can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a color image regeneration device that performs color regeneration by outputting multicolor dots.

(Prior Art) In recent years, consideration has been given to using electrophotographic color copying machines as color CART output printers and color facsimile terminals by aging them with laser beams. This is because it is expected to have many uses as a device that can quickly convert output signals from computers into color images. However, with the current umbrellas, it is not possible to obtain high-quality color reproduction images because an image processing technology capable of faithful color reproduction has not been established.

Particularly in devices that obtain desired color reproduction images using electrophotography, when the color materials yellow, magenta, and cyan are subtracted and mixed, the spectral reflection characteristics of each color material are not ideal, resulting in a muddy color and one-color reproducibility. becomes worse.

(Objective) The present invention has been made in view of the above points, and an object of the present invention is to provide a color image reproducing device that can obtain high quality color reproduced images. (Embodiments) Examples of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows a color electrophotographic recording apparatus to which the present invention can be applied. In FIG. 1, a semiconductor laser light source unit 1 is provided, and a collimated light beam modulated by an image signal is emitted from this light source unit. This original beam is deflected by an original deflector 2 made of a rotating polygonal mirror or the like, passes through an imaging lens 6, and is imaged on a photosensitive drum 4 to form an image. In that case, the photosensitive drum 4 is neutralized by the charger 4a, then uniformly charged by the charger 4b, and then exposed to a light beam at the same time as the charge is removed by the charge remover 4C, so that an image is formed on the photosensitive drum 4. A corresponding electrostatic latent image is formed. Subsequently, the latent image thus formed is developed by the developing devices 5a to 5d.

The developing units 5a to 5d each contain toners of Y (yellow), M (magenta), C (cyan), and Bl (black), and one of them is selected. That is, the input signal is separated into four colors each of Y, M, C, and Bl, and a modulated beam corresponding to each color is emitted from the semi-binding unit 1 for each color. The corresponding developing device is driven. The toner images of the respective colors formed on the photosensitive drum in this manner are transferred onto the recording paper 7 wrapped around the transfer drum 6 in a superimposed manner.

The radius ratio between the photosensitive drum 4 and the transfer drum 6 is 2:1, and an image is recorded on each half of the photosensitive drum. That is, while development is being performed on one half of the photosensitive drum 4, charging or latent image formation is performed on the other half.

FIG. 2 shows a horizontal synchronization method for the device shown in FIG. Components having the same functions as in FIG. 1 are given the same reference numerals. The laser beam LB output from the laser light source unit 1 is polarized by the rotating polygon mirror 2, and scans on the photosensitive drum 4 as shown in the figure.A light receiving element 10 is installed on the laser beam scanning line, and the laser The light source unit 1 is configured to emit a modulated beam corresponding to image data after a predetermined timing after the light receiving element 10 detects the laser beam.

FIG. 6 shows a method for reproducing a color image in this embodiment. 1 pixel that reproduces a color image is l1xll
In this embodiment, the diameter of the laser scanning the photosensitive drum 4 is 3/! It is set to l. In other words, laser beam scanning is performed at a pitch of %l in both the main scan It is meant to be expressed. (
As can be seen from the figure (Fig. 6 solid line square part)
), magenta CM), cyan (C), black (Bt)
In the scanning of each color, the main scanning X scans every other dot, and the sub-scanning Y scans every other line, and only an area of 1% of one pixel is scanned.

For example, when scanning yellow (Y), the sub-scan Y is
, ■, ■, etc., and the main scan scans the odd numbered dots as in ■, ■, ■, etc. In other words, ``each color data is scanned only in an area corresponding to % of the output pixel, and is prevented from overlapping each other, thereby improving color reproducibility when multiple colors are output to the same pixel.

Note that the diameter of the laser beam dot can be varied by pulse width modulation.

FIG. 4 is an example of a block circuit diagram of the can-image reproducing apparatus of the present invention. In the figure, 10 is a terminal for inputting color-separated binary pixel data V, 11 is a line memory for temporarily storing input pixel data VID, 12 is a control unit for controlling input pixel data V, and 16 is a terminal for inputting color-separated binary pixel data V. 2 In the horizontal synchronization detection circuit that detects the laser beam using the light receiving element in Figure 10, the horizontal synchronization signal H8 is generated every time the laser beam is detected.
Emit YNO20. To explain the operation, first, color-separated yellow (Y) image data V is stored in line memory 1.
It is stored in 1. The control unit 12 outputs the horizontal synchronization signal H8YNO after the yellow (Y) pixel data output start timing.
20, the address signal ADH is sent to the line memory 11.
supply to.

The address signal ADH is supplied by the control unit 12 so that one line of pixel data is sequentially read out from the line memory 11 in synchronization with a pixel data transfer lock CLK 22 in which one period is the time for scanning the laser beam by l. . Yellow (Y) sequentially read out from line memory 11
) is input to AND circuits 16 and 17. The AND circuit 17 is supplied with the pixel data transfer clock OLE 22, and the AND circuit 16 is supplied with the pixel data transfer clock (J) via the inverter 18.
, OLK 2 which has a phase difference of 180° from K 22
4 is supplied. Pixel data transfer lock O
The output width of yellow (Y) pixel data read out from the line memory 11 is divided into the first half and the second half using the LK 22 and the AND circuits 16 and 17. Also yellow (Y
), the control unit 12 applies the select signal 26 to the selector 14 to select and output the first half of the output width of the input pixel data, that is, the pixel data input to the terminal 2. In this way, only the first 1,000 copies of the normal output width of yellow (Y) pixel data is output for one line. When a horizontal synchronizing signal H8YNC20 indicating that the first line is to be scanned after one laser beam scan for yellow (Y) K is input, the control section 12 does not read out the line memory 11. That is, for yellow, every other line is scanned.

Next, for magenta (M), every other line is scanned at the same scanning position as for yellow (Y).

The selector 14 selects and outputs the second half of the output width, that is, the pixel data input to the terminal 1, from the output pixel data V from the terminal 0 as OUT.

For cyan (C) and black (M) pixel data, the horizontal synchronization signal H8YNO20 after the output start timing
When , no output is performed and the color is yellow.

Scanning is performed every other line, which is different from the magenta line. Similarly, cyan (C) selects the first half of the output width of pixel data as black (IM selects the second half).

The operation of this embodiment will be explained in more detail using the timing chart of FIG. 5. Each color is yellow (Y), magenta (M), and cyan (C).

Let A be the output start timing of black (E13).

First, the case of yellow (Y) output will be explained. The control unit 12 starts counting from the rising edge of H8YIJO next to timing A, and when it reaches a certain value, starts timing B.
The address signal ADR21 is supplied to the line memory 11, and the pixel data of yellow (Y) stored in the line memory 7'c is read out.

A gate is performed by the transfer lock CLK 22, and OUT Y is output from the yellow (Y) image output V only during the first half 3AT of the transfer time T of one clock. Yellow (Y)
Data output for one line is finished at timing D, and yellow (Y) data is not output at timing D of the primary l18YNC. After that, every other HBYkJC has the same 4
υ1 and outputs yellow (Y) pixel data.

In the case of magenta (M), the timing output is similar to that of yellow from output start timing A, but OU
TM is gated by the clock OLK 24, so it is 1
The second half of the clock transfer time T is the output section.

For cyan (0) and black < B11), H8YNC at timing A! Then, when the horizontal synchronizing signal H8YNC at timing D is not output and the horizontal synchronizing signal H8YNC is input, the address signal ADR22
The contents of the line memory 11 are read out. 0UTC is clock C from the cyan image 1 output V! LK22
Since it is gated by the clock OLK 24, the first half y2T of one clock transfer time T becomes the output section, and since the clock OllTM is gated by the clock OLK 24, the second half y, T
is the output interval.

(Effects) As detailed above, since dots of each color are outputted so that the color materials of each color do not overlap in one pixel, a high-quality color reproduction image can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a color electrophotographic recording device to which the present invention can be applied, FIG. 2 is a diagram illustrating the horizontal synchronization method of the color electrophotographic recording device of FIG. 1, and FIG. Figure 4 is a block circuit diagram of this embodiment;
FIG. 5 is a timing chart for explaining the operation of each part of the 41st part. Here, 1... Semiconductor laser light source unit 4... Photosensitive drum 10... Light receiving element 11... Line memory 12... Control circuit 16... Horizontal synchronization detection circuit 14... Selector 1<S , 17...AND circuit 18...inverter. i knee, ・

Claims (1)

[Claims] A color image reproducing device that reproduces a color image by forming dots with a beam, characterized in that said beam is modulated so that dots of each color do not overlap with respect to one color pixel to be reproduced.