JPS58158623A - Wide area photoscanning system - Google Patents

Abstract

PURPOSE:To prevent the disorder of print, etc., by devising a connection at the boundary point of each partial scan in a main scanning direction. CONSTITUTION:Light projected from a light source 2 is reflected by the specular surface (f) of a rotary polygon mirror 1, which rotates to scan in a scanning direction from 16 to 17 through an optical system 6 for image formation and a plane mirror 4. When the specular surface (f) reaches a position (f'), the lightprojected from a light source 3 is reflected by the specular surface (f') and further reflected by a plane mirror 5 through an optical system 7 for image formation to scan in a direction form 17 to 18. A means for detecting boundaries of partial scans is provided to generate detection signals for the starting and ending points of the partial scans. In this case, light from light sources 2 and 3, or 8 and 9 can be used under the control of the optical systems.

Description

DETAILED DESCRIPTION OF THE INVENTION (211 Invention CI) Technical Information The present invention relates to a wide-area optical scanning device, and more particularly to an optical scanning method that achieves wide-area optical scanning by dividing a scanning area into a plurality of partial scanning areas.

fbl Technology background A printer S that forms a submerged layer on a photosensitive drum using a laser source, develops it with toner, transfers it to paper, and prints characters, etc.
It is used. However, the printers currently in use have a relatively small paper width υ).
There is a desire S to print on a large and wide paper surface, and for this purpose it is necessary to increase the width of the photosensitive drum and the optical scanning width.

I7 However, there is a limit to enlarging the entire scanning width using one light source, therefore, use multiple light sources, divide the entire scanning width into multiple parts using multiple optical systems, and expand the area divided into the multiple parts. Each optical system is in charge of partial scanning, and the partial scanning circuit is connected to the scanning line to complete a series of scans. (partial scanning υ) at the connection point, that is, at the boundary, the previous stage 0) partial scanning σ) the next stage from the final modulation point 0] If the distance of the black cloth at the start of modulation in a partial scan is different from the distance between adjacent modulation points i and 7 in the same partial scan, it will be unsightly. For example, when printing characters, the former will be distorted in the sub-scanning direction of the printing rod, and the latter will result in uneven dot spacing. Therefore, countermeasures against the above problems are desired.

(cl Invention θ) Purpose Invention υ) Purpose r Based on the above request, we devised connections in the main scanning direction of the partial scans at the boundary points of each partial scan to achieve wide-area optical scanning without causing print disturbances, etc. The goal is to provide a method.

fdl Structure of the Invention The structure of the present invention detects the boundary between red and blue parts scanned individually by eight optical systems and outputs the scanning start point detection signal and the scanning*? P
! A circuit that generates an end point detection signal is provided, and counting is started by the scan start point detection signal of the partial scan that starts the entire scan first, and the counting is completely stopped by the scan end point detection signal of the partial scan σ). Counting continues and restarts again with the scan start point detection signal of the partial scan, stops counting again with the detection signal at the end of the scan of the partial scan, and continues counting 1c with the scan start point detection signal of the next partial scan. A power panonta is provided, and the counter is incremented by the modulation position control sub-clock, and the variable light modulation clock 7 is controlled in synchronization with the modulation position control suck lock by the output of the counter. By configuring σ) as shown above, the distance from the final modulation point of the previous partial scan to the black cloth at the end of the scan is counted and stored, and the next partial scan is started to check the start of the scan of the partial scan. When the output signal is detected, the counter resumes counting continuously, so that the distance from the scanning start point to the modulation start black cloth is calculated.

fel Embodiment of the Invention FIG. 1 shows an example of the configuration of a wide-area optical scanning device to which the present invention is fully applied. 1 is a rotating polygon mirror, and 2 and 3 are light sources. The light projected from the light source 2 is reflected at f, one of the mirror 3 surfaces of the rotating polygon mirror 1, and if the rotating polygon mirror is rotating in the direction shown by the arrow, the imaging optics It passes through the system 6, is reflected by the plane mirror 4, and scans in the direction from 16 to 170) as shown in the scanning direction. If tl-person is between 16 and 17, then A indicates the area of the first partial scan. Rotating polygon mirror 1 force S
When the mirror surface f rotates and reaches the position f', the light projected from the source 3 is reflected on the mirror surface f' and passes through the imaging optical system 7 to the plane #! It is reflected by 5 and scans in the direction from 17 to 18. If 6B is set between 17 and 18, B indicates the area of the second partial scan.

16.17, 1F3 is provided with a means for detecting the boundary of partial scanning to obtain a scanning start point detection signal and a scanning end point detection signal, but there is no method or method using the light from light sources 2 and 3 by controlling the optical system. As in the example, there is a method of providing light sources 8 and 9 and using the light. Incidentally, the positional deviation in the sub-scanning direction caused by the temporal delay of each partial scan can be avoided by, for example, the deflector 2 (1 (deflection I) inserted between the plane mirror 4 and the scanning surface 19.
I: may be constant).

FIG. 3 is a waveform diagram illustrating the operating principle of the present invention. In FIG. 2, a modulation control unit 5 generates an optical modulation clock by the output of a counter 14 which is incremented by a suck lock for modulation position control. Powerful. As shown in FIG. 1, when the number of divisions of the entire scanning area is 2, the scan start point detection signal generator 10 starts the counter 14 at the scan start point shown in FIG.
Fully start up.

The scan end point detection signal generator 11 detects all the scan end points at the boundary point shown in FIG. 17 (stops the counting of the 7 counter 14, and holds the count value σ) until then. Rotating polygon #! When the mirror surface f of I rotates and reaches the position of the 11th surface and starts scanning the partial scanning area B, the scanning start point detection signal generator 12 counter 14 is activated again by the light passing through the boundary point 17, and the holding ( Counting is started from the count value that was 7. When the scanning t reaches 8 in Fig. 1, the scanning end point detection signal generator 1
3 completely resets the counter 14. In FIG. 3, it is generated by optical modulation, and the frequency is ]/. If the dotted line is the boundary between partial scans A and B shown in FIG. In this case, it becomes a scanning start point detection signal. Output data is modulated at the rising edge of the optical modulation clock.

If the interval between the output data is ft and the interval between the output data between the boundary tubes shown by the dotted line is y2 t/, then t' is 0 as shown below.
It is obtained from Eq.

Therefore, t' can fall within an error range of 2/+1 or less with respect to t. As in this example, if <K=10, t' is 0.91 to 1
．． 1t range.

If the present invention is not applied 0≦t'≦(1+-)t Therefore, the error range is significantly improved.

(G) Effects of the Invention (B) As explained above, the present invention provides a method for determining the difference between the distance zl of the modulation start black cloth from the final modulation point between adjacent partial scans and the distance t between adjacent modulators 2 within the partial scan range. can be made smaller, and the effect is significant.

[Brief explanation of drawings]

Fig. 1 shows the configuration of a wide-area optical scanning device to which the present invention is fully applied, and Fig. 2 shows an example of the present invention. Block diagram of the circuit shown, 3rd
The figure is a waveform diagram illustrating the operating principle of the present invention. 1 is a rotating polygon mirror, 2 + 3.8 t 9 is a light source, 4 and 5 are plane mirrors, 6 and 7 are light beam systems, 10°12 is a scanning start point detection signal generator, 11.13 is a scanning end A point detection signal generator, 14 a counter, and 15 a modulation control section.

Claims (1)

[Claims] 1 item 0) A rotating polygon mirror and the rotating polygon mirror 0) N light sources that project light onto N different mirror surfaces and the camphor force of the projected light) σ) Reflected light All images are formed on the same scanning line In a wide-area optical scanning device, which has N optical systems, and completes a series of scans by continuously forming N images by the N optical systems,
partial scans υ) individually scanned by the N optical systems;
Means for detecting all the boundaries and generating a scan start point detection signal and a scan end point detection signal; Means for counting and storing the distance of the scan end point distribution from the final modulation point of partial scan; and Modulation from the scan start point of partial scan. means for calculating the distance to the starting point based on the scanning starting point detection signal and the stored distance; A wide-area optical scanning system whose main feature is distance control.