JPH0510868B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application) The present invention relates to a registration adjustment device for a multicolor printer. The present invention relates to a registration adjustment device for a multicolor printer that prints in a plurality of colors.

(Prior Art) Electrophotographic printers have been known as printing devices for computer output. FIG. 1 shows an outline of a printer device for printing in two different colors.

Two print transfer units 1 along the recording paper conveyance path 30
0 and 20 are placed. Each print transfer section 10, 20
are photosensitive drums 11, 21, developing devices 12, 22,
It is composed of transfer corotrons 13, 23 and optical scanners 14, 24.

When the recording paper stored in the paper tray 31 is conveyed along the recording paper conveyance path 30 and reaches the scheduled position upstream of the photosensitive drums 11 and 21,
A #1 page start signal is supplied to the print transfer section 10, and the photosensitive drum 11 is scanned by the optical scanner 14.
Exposure to light begins.

As is well known, for example, in the print transfer unit 10, the optical scanner 14 includes a laser beam generator, a laser beam focusing/deflecting device, and a #1 video signal or print pattern signal of the laser beam. The laser beam is deflected and scanned on the photosensitive drum 11 by a scan start signal, and its intensity is modulated by a #1 video signal.

As a result, # is deposited on the surface of the photosensitive drum 11.
An electrostatic latent image corresponding to one video signal is formed. Thereafter, development is performed using toner of a desired first tone (for example, black) using the developing device 12, and then this image is transferred onto the recording paper using the transfer corotron 13.

Through the same procedure, the print transfer section 20 transfers an image using toner of a second tone (for example, red) based on the #2 video signal, and the fixing device 32 fixes the transferred image onto the recording paper. .

The recording sheets onto which the two-color toner images have been transferred and fixed in the manner described above are accumulated in the stacker 33.

In this case, in order to write two-color images of the first and second tones on the respective photosensitive drums 11 and 21, the two optical scanners 14 and 24 receive video signals corresponding to the images of the first and second tones, respectively. It is natural that this is given.

The timing of giving the video signal--i.e.
FIG. 2 shows an example of the scan start signal SSS and page start signal PSS.

As is clear from this figure, the two print transfer sections 10 and 20 write video signals of respective tones onto separate photosensitive drums 11 and 21, so two types of tones corresponding to the same page are supported. The writing timing of the video signal will be different.

That is, the difference t between the rise times of the #1 and #2 page start signals PSS for the same page in FIG. 2 is determined according to the interval between the two photosensitive drums 11 and 21 in FIG. .

An example of a conventional print pattern generating device is shown in FIG. As mentioned above, the printing pattern generating device is provided individually (exclusively) for each of the optical scanners 14 and 24, but since their configurations are exactly the same, only one printing pattern generating device will be described here.
Color--For example, only a print pattern generator for black will be illustrated and described.

In the page buffer 41, a video signal corresponding to a character (image) to be printed in black (generally, a designated color) in a page of image to be printed is sent to the processor using a commonly known method. (not shown) and stored.
In this case, the video signal -- that is, the print data -- consists of a character code and color designation data.

The print data stored in the page buffer 41 is taken out line by line and put into the line buffer 42. The mapping processor 43 takes out data one character at a time from the line buffer 42 and calculates the address of the font memory 44 and the print position.

According to instructions from the mapping processor 43, the print pattern read from the font memory 44 is written to a corresponding position in a pair of output buffers 45, 46 having a capacity for one scan.

Writing and reading are performed alternately in the output buffers 45 and 46 by switching the switches S1 and S2, and the read data is transferred to the optical scanner 14 as a video signal.

The operations and timing of the page buffer 41, row buffer 42, mapping processor 43, font memory 44, and output buffers 45 and 46 as described above are controlled by a sequence control circuit 49. .

That is, as is well known, the sequence control circuit 49 receives the page start signal #1-
PSS and scan start signal #1-SSS are supplied to generate signals for controlling the operation timing of each of the above-mentioned units.

In this way, when an image is formed on the photosensitive drum 11 by the scan method and transferred to recording paper, the scannable area on the photosensitive drum 11 (hereinafter referred to as physical imaging space) and the the area in the physical imaging space that is actually imaged by the scan;
Alternatively, it is necessary to correctly adjust the positional relationship with the area on the photosensitive drum 11 (hereinafter referred to as logical imaging space) that the recording paper comes into contact with during transfer.

This will be further explained below with reference to FIG.

In FIG. 4, the physical imaging space 17 is a scannable area on the photosensitive drum 11 as described above, in other words, an image (toner image) can be formed at any position within this area. can do.

Note that the arrow 18 is the rotation direction of the photosensitive drum 11 or the conveyance direction of the recording paper, and the arrow 19 is
This is the longitudinal direction of the photosensitive drum 11 or the scan direction by the optical scanner 14.

Further, the logical imaging space 16 is an area on the photosensitive drum 11 that the recording paper comes into contact with during image transfer.

As is clear, in order to correctly transfer the toner images formed on the photosensitive drums 11 and 21 onto the recording paper, it is necessary to form the toner images only within the range of the logical imaging space 16.

For this reason, in conventional single-color scanning laser printers, etc., an XY coordinate plane is assumed whose origin is the intersection point O of the contour line in the scan direction and the drum rotation direction in the physical imaging space, and its coordinates (X1, The scan timing is controlled so that an image is formed using a video signal only within an area corresponding to the size of the recording paper (the range of the logical imaging space 16) using the point O1 of Y1) as the starting point or origin. ing.

In this case, the coordinate X1 is represented by the number of dots in the scanning direction, and the coordinate Y1 is the number of dots (or the amount of transport) in the recording paper transport direction.
(or the rotation angle of the photosensitive drum, etc.).

For this purpose, an X margin register and a Y margin register for storing the X1 and Y1 are provided in the print pattern that generates the video signal.

That is, in the conveyance direction of the recording paper, after performing a Y scan from the origin O of the physical imaging space 17, and in each scan,
The application timing of the video signal to the optical scanner 14 is controlled so that image writing (exposure) using the video signal starts after the X-th dot counting from the beginning.

Therefore, the X margin register and Y
By adjusting the value of the margin register, the image can be printed at the correct desired position on the recording paper.

By the way, in a conventional two-color (generally multicolor) printer as shown in FIG.
It is common practice to adjust the margins in the second color print transfer section 20 (or subsequent print transfer sections) by adjusting the positions and installation intervals of and 21.

However, in reality, due to thermal expansion and contraction of various parts of the device due to temperature changes, or expansion and contraction of recording paper due to changes in temperature and humidity, the printing position in the first color print transfer section 10 and the second color print transfer section There is a drawback that the printing position at 20 (or the subsequent printing transfer section) is misaligned.

As can be easily understood, in the case of multicolor printing, if there is a color shift even by a few dots, the quality of the print will be extremely degraded, resulting in an extremely unsightly image.

(Purpose) The present invention has been made in order to eliminate the above-mentioned drawbacks, and its purpose is to make the printing (printing) position of the second and subsequent colors so that the printing (printing) position of the first color
To provide a registration adjustment device for a multicolor printer that can prevent misalignment with respect to the position and obtain multicolor prints without color shift.

(Overview) In order to achieve the above object, the present invention provides the above-mentioned X
The feature is that a margin register and a Y margin register are provided individually.

(Example) The present invention will be described in detail below with reference to the drawings.

FIG. 5 is a block diagram of one embodiment of the present invention. In this figure, the same reference numerals as in FIG. 1 represent the same or equivalent parts.

As is clear from a comparison with FIG. 1, this embodiment uses a video signal supplied to each optical scanner 14, 24, that is, a print pattern signal corresponding to a color tone corresponding to information obtained by color-separating one print pattern. a printing pattern generating section 40 for generating
50, each independent X margin register 40
A, 50A and Y margin register 40B, 5
0B is provided.

Next, the margin adjustment operation in this embodiment will be explained with reference to FIG. In addition, the 6th
In the figure, the same reference numerals as in FIG. 4 represent the same or equivalent parts.

In the figure, section A on the right side represents the relationship of the imaging space in the print transfer section 10 of FIG. 1 or FIG.
It represents the relationship between imaging spaces at 0.

16-2 and 17-2 are a logical imaging space and a physical imaging space in the second color print transfer section 20, respectively.

First, X and Y margin registers 40A, 4
The location of the logical imaging space 16 is adjusted by inputting the stored contents of 0B from, for example, a numeric keypad (not shown) on the console. Thereby, it is possible to perform printing in the first color on a desired position or area on the recording paper.

Thereafter, the recording paper is conveyed along the recording paper conveyance path 30, and printing in the second color is performed in the print transfer section 20.

However, in this case, for the reasons mentioned above, the position of the origin O-2 in the print transfer section 20 in the X direction (that is, in the longitudinal direction of the photosensitive drum 21) is
As shown by the symbol d in FIG. 6, the origin O in the print transfer section 10 may be shifted from that of the
Furthermore, the Y-direction shift Y2 of the logical imaging space 16-2 with respect to the origin O-2 may also change.

Therefore, if a color shift occurs as a result of printing the second color, the X2 margin register 50A and Y2 margin register 50B
The color shift can be eliminated by resetting the stored value of and moving the position of the logical imaging space in the same manner as described above.

In this case, the amount and direction of color shift are as follows:
The user can inspect the printed image and make the determination, or it can be automatically determined mechanically and automatically adjusted and determined.

Furthermore, although the above description has been made of the case where the present invention is applied to a two-color printer, it can also be applied to a multi-color printer by providing X and Y margin registers in the print pattern generation section of each print transfer section.
It will be clear that the respective color shifts can be eliminated in a similar manner.

(Effects) As is clear from the above description, according to the present invention, the following effects are achieved.

(1) Since X and Y margin registers are provided in the print pattern generation part of each print transfer part,
The printing position relative to the recording paper can be adjusted independently for each color, and a high-quality multicolor print image without color shift can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the configuration of a printing section of a general two-color printer, FIG. 2 is a waveform diagram for explaining the printing timing in the two-color printer, and FIG.
The figure is a block diagram showing the configuration of one color of a conventional multi-color print pattern generator, FIG. 4 is a diagram showing the positional relationship between the physical imaging space and the logical imaging space in a conventional monochrome printer, and FIG. FIG. 6 is a schematic diagram showing the main structure of a two-color printer according to an embodiment of the present invention. FIG. 6 is a diagram showing a physical imaging space and a logical imaging space in the embodiment. 10,20...Print transfer section, 11,21...Photosensitive drum, 12,22...Developer, 13,23...
... Transfer corotron, 14, 24 ... Optical scanner, 30 ... Recording paper conveyance path, 32 ... Fixing device,
40... Print pattern generation unit, 41... Page buffer, 42... Line buffer, 43... Mapping processor, 44... Font memory, 45-
48...Output buffer, 49...Sequence control circuit, 40A, 40B, 50A, 50B
...margin register.

Claims (1)

[Claims] 1. It has a plurality of print transfer sections arranged in order at intervals along the recording paper conveyance path, and each print transfer section includes at least a photosensitive drum, a developer, a transfer corotron, and an optical scanner. each optical scanner is connected to a print pattern generator that supplies a print pattern signal corresponding to the color tone corresponding to the color-separated information of one print pattern; A registration adjustment device for a multicolor printer configured to form a latent image on the photosensitive drum, wherein each print pattern generation section has a logical registration adjustment device for a physical imaging space in a corresponding print transfer section. A registration adjustment device for a multicolor printer, characterized in that it independently has an X margin register and a Y margin register for determining the relative position of an imaging space.