JP2001038964A - Printer controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the structure by providing means for generating band unit display list, means for converting band raster data and means for correcting skew/magnification for a page of image data and correcting positional shift thereby reducing the circuits or memories required for each correction. SOLUTION: The printer controller comprises a band raster converting means for reading out display lists in units of band and converting raster data for a band buffer, an ROM 2 for storing control program thereof, and a RAM 3 for storing a page of image data received from a personal computer 101 through an input interface 105 in the subscanning direction in a receiving buffer region 6 and raster data corresponding to each color in band buffer regions 8c-8k. A shift detected by a skew/magnification detecting means 111 is transmitted to a printer engine 5 and the results of the skew/magnification detecting means are delivered through an engine interface 109 to an imaging means 114.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tandem type color image forming apparatus having an electrophotographic mechanism having a plurality of photosensitive members, a plurality of line type ink jet mechanisms, and the like. The present invention relates to a printer controller having a function of correcting distortion.

[0002]

2. Description of the Related Art In recent years, a tandem type in which a full-color image is formed by superimposing and transferring each color image of a cyan image, a magenta image, a yellow image, and preferably a black image employing an electrophotographic method or an ink jet method on a sheet material. Color image forming apparatuses have become widespread. However,
The above-described color image forming apparatus has a problem in how to properly correct the positional deviation of each image formed by different image forming units, and a tandem type color image forming apparatus that corrects the positional deviation. Various devices have been proposed.

A conventional tandem type color image forming apparatus for correcting a displacement will be described below with reference to the drawings.

FIG. 4 is a functional block diagram of a conventional tandem type color image forming apparatus having a correction function.

[0005] In FIG. 4, reference numeral 101 denotes a personal computer (CAD, workstation, digital camera, or the like, but not shown) for generating image data to be printed; 102, a printer controller;
Denotes a printer engine, and the printer controller 10
2 converts the image data received from the personal computer 101 into raster data and transmits the raster data to the printer engine 103. 104, a tandem type color image forming apparatus having a printer controller 102 and a printer engine 103; 105, an input interface for receiving image data transmitted from the personal computer 101 and storing it in an internal reception buffer; 106, data communication and a printer engine A microprocessor for controlling printing by 103; a ROM 107 for storing a control program for operating the microprocessor 106 and parameters used for the processing; a raster 108 for storing raster data developed by the microprocessor 106 RA
M and 109 are engine interfaces for transmitting raster data stored in the RAM 108 to the printer engine 103, 110 is a line memory for storing data of lines in the printing sub-scanning direction by an amount required for correction, and 111 is a printing position described later. A skew / magnification detecting means 112 for detecting a shift, a skew / magnification correction coefficient calculating means 112 for calculating an alignment amount of each image according to the positional shift amount detected by the skew / magnification detecting means 111, and a skew / magnification 113 A skew / magnification correction unit 114 that performs correction based on the correction coefficient calculation unit 112, and an image forming mechanism 114 that forms an image on a transfer material (not shown) based on the corrected data.

Next, the image forming mechanism 114 will be described below with reference to the drawings.

FIG. 5 is a configuration diagram of a general image forming mechanism (printer engine).

In FIG. 5, 21c, 21m, 21y, 21c
21k is an image forming station corresponding to each color of cyan, magenta, yellow, and black, 22c, 22m, and 2
2y and 22k are photosensitive members as image carriers, 23c and 23
m, 23y and 23k are chargers, 24c, 24m and 24
y, 24k are developing units, 25c, 25m, 25y, 25k
Is a cleaning unit, 26c, 26m, 26y, and 26k are exposure units, 27 is a transfer unit, and 28c, 28m, 28y, and 28
k denotes a transfer unit constituting the transfer unit 27, 29c, 29m, 2
9y and 29k are laser beams, 30 and 31 are driving rollers for driving an intermediate transfer belt 32 described later, 33 is a control unit, 34 is a paper feed cassette, 35 is a sheet material, 36 is a paper feed roller, and 37 is a sheet. Material transfer roller, 38 is a fixing device, 3
8a is a heating roller.

The image forming mechanism 11 configured as described above
The operation of No. 4 will be described below.

First, a black component color latent image of image information is formed on a photoreceptor 22k by a known electrophotographic process means such as chargers 23k and 26k of an image forming station 21k. Is visualized as a black toner image by the developing material having the black toner, and the black toner image is transferred to the intermediate transfer belt 32 by the transfer unit 28k. Hereinafter, the cyan toner image, the magenta toner image, and the yellow toner image are similarly transferred. When the superposition of the four color toner images on the intermediate transfer belt 32 is completed, the paper feed roller 36 feeds the paper feed cassette 34.
The four color toner images are collectively transferred and conveyed by a sheet material transfer roller 37 onto a sheet material 35 such as paper fed from
The sheet is heated and fixed by the fixing device 38, and a color image is obtained on the sheet material 35.

As described above, since the image forming station is provided for each color, the speed of the image forming operation can be increased. However, the displacement of the transferred image of each color formed in a different image forming station occurs.

The following describes the displacement of the transferred image.

FIG. 6 is a view showing a positional shift of a transferred image in the tandem type color image forming apparatus. FIG. 6 (a) shows a positional shift (hereinafter referred to as sub-scanning) in the transfer material moving direction (arrow A direction in the figure). FIG. 6B is a diagram showing a positional deviation (hereinafter, referred to as a main scanning positional deviation) in a scanning direction (a direction perpendicular to the direction of arrow A in the figure). 6
FIG. 6C is a diagram showing an oblique displacement (hereinafter, referred to as a skew error), FIG. 6D is a diagram showing a magnification error, and FIG. 6E is a diagram showing a curvature error. FIG. In the actual transfer image, an image in which the above five types of positional deviations are superimposed appears.

Hereinafter, the main causes of the above-described five types of positional deviations will be described.

The sub-scanning position shift shown in FIG.
The main causes of the main scanning position shift shown in (b) are shifts in the mounting of the image forming stations 21c, 21m, 21y, 21k and the scanning optical system, and shifts in the mounting of lenses and mirrors (not shown) in the scanning optical system. . The main cause of the oblique displacement shown in FIG. 6C is the image forming station 21.
c, 21m, 21y, and 21k, the angular deviation of the rotation axis of the photosensitive drum and the mounting angular deviation of the scanning optical system. The main cause of the shift due to the magnification error in FIG. 6D is a shift in the scanning line length due to an error in the optical path length from each scanning optical system to the photosensitive drum of the image forming station. FIG.
The main cause of the deviation due to the curvature error in (e) is an assembly deviation of a lens or the like in each scanning optical system.

[0016]

However, the above-described conventional printer controller has the following problems.

A. To correct the skew / magnification of the printer engine 103 with respect to the raster data generated by the printer controller 102, the printer engine 1
On the 03 side, the line memories 110 for the number of lines required for correction
And circuits are required, and productivity is lacking.

The present invention solves the above-mentioned conventional problems. By correcting a position shift in a printer controller, the number of circuits and memories for skew correction and magnification correction on the printer engine side is reduced, and the configuration is reduced. An object of the present invention is to provide a simple tandem type color printer.

[0019]

According to the present invention, there is provided an image forming apparatus comprising: an image formed by an n-color toner or ink;
A printer controller for generating image data of a tandem-type image forming apparatus that forms a divided image for each color by image forming means (1 <m ≦ n) and superimposes n colors to form a composite image; A band-unit display list generating means for generating a band-unit display list, which is a band-unit drawing list, while dividing image data for one page of printing received via the printer into α bands in the printing sub-scanning direction; Band raster data conversion means for converting the unit display list into band raster data, which is raster data in band units, while reading the display list in band units; and mechanical and optical accuracy of m image forming means for the band raster data. Skew and magnification correction means for correcting relative distortion such as skew and magnification caused by It has a structure in which and a band buffer memory for holding the band raster data 3 or band of for each m pieces of said image forming means.

This configuration has the following operation.

A. After converting the image data received via the interface into raster data in band units, skew and magnification correction is performed on the raster data, and the corrected raster data can be sent to the printer engine. It is possible to provide a printer controller that can realize a correction mechanism having a simple configuration without adding a line memory, a circuit for correction, and the like to the printer engine.

Here, the band buffer memory must be able to hold three or more bands of band raster data. When correcting raster data developed in band units, raster data for two bands is required, and buffer memory for the remaining one or more bands is stored in buffer memories for one or more bands. This is for developing raster data.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A printer controller according to a first aspect of the present invention forms an image of n colors of toner or ink or the like by m (1 <m ≦ n) image forming means by dividing the image into color units. A printer controller for generating image data of a tandem-type image forming apparatus that forms a composite image by superimposing n colors, wherein α image data of one print page received via an interface is α data in a print sub-scanning direction. A band-unit display list generating unit that generates a band-unit display list that is a band-unit drawing list while dividing the band into bands, and reads the band-unit display list into band-band raster data that is band-unit raster data while reading the band-unit display list. Band raster data conversion means for converting, and m number of the image Skew / magnification correcting means for correcting relative distortion such as skew / magnification caused by mechanical and optical accuracy of the forming means, and the band raster data for each of the m image forming means for three or more bands. And a band buffer memory.

According to this configuration, after converting into raster data in band units, the data can be sent to the printer engine while performing skew and magnification correction when the raster data is read. A correction mechanism having a simple configuration can be realized without adding a memory, a control circuit for operating the line memory, a correction circuit, and the like.

Embodiment 1 Hereinafter, Embodiment 1 of the present invention will be described with reference to the drawings.

FIG. 1 is a functional block diagram of a tandem-type image forming apparatus according to Embodiment 1 of the present invention.

In FIG. 1, 101 is a personal computer, 105 is an input interface, 106 is a microprocessor, 109 is an engine interface,
Numeral 111 denotes a skew / magnification detecting means, and numeral 114 denotes an image forming mechanism, which are the same as those in the prior art. Reference numeral 1 denotes a tandem type color image forming apparatus according to the first embodiment;
Is a ROM that stores a control program that reads a display list in band units and performs raster data conversion on a band buffer. Reference numeral 3 denotes a RAM that temporarily stores received image data received via the input interface unit 105. The buffer area 6, a banding-compatible display list area 7 for storing image data stored in the reception buffer area 6 as a display list, and raster data corresponding to each color (cyan, magenta, yellow, and black) are developed. Band buffer areas 8c, 8m, 8y, and 8k. Reference numeral 4 denotes a printer controller according to the first embodiment, and reference numeral 5 denotes a printer engine according to the first embodiment.

FIG. 2 is a diagram showing an example of a document to be printed according to the first embodiment of the present invention.

In FIG. 2, n, n + 1, n + 2, n +
Reference numeral 3 denotes a band when the display list for one page is divided into four bands, and the display list of each band indicates that a part of the character “A” is drawn. For example, as a display list of band n, a description that “is a part above the character“ A ”” or a print portion called a scan line is a set of vectors in one direction (for example, horizontal direction). These methods also include coordinate information, color information, pattern information at the time of painting called a brush, and the like.

FIG. 3A is a diagram showing the state of the cyan band buffer 8c during raster data developing operation on the (n + 2) th band, and FIG. 3 (b) is the cyan band buffer during raster data developing operation on the (n + 3) th band. It is a state diagram of the band buffer 8c.

In FIG. 3A, the band buffer 8c
Can hold band raster data for three bands,
It holds raster data of bands n and n + 1 that have already been developed and n + 2 data that is currently being raster data developed.
In FIG. 3B, the data of (n + 2) has already been developed into raster data, and the raster data is currently being developed in the (n + 3) th band.

The image forming operation of the tandem-type color image forming apparatus 1 configured as described above will be described below.

First, in the personal computer 101, color image data to be printed as shown in FIG. 2 is created by a user's input operation.

Here, when printing is performed, the skew / magnification detecting means 111 detects the amount of displacement.
Specifically, a pattern serving as a reference for color misregistration (hereinafter referred to as a registration pattern) is drawn in advance, a registration pattern is detected by a plurality of sensors (not shown), and a misregistration amount is calculated from the result. I do. In the first embodiment, it is assumed that when the data expanded into the raster data is directly transmitted (without correction) to the printer engine and printed, the cyan color is printed in an inclined manner to the upper right.

When a print command for the created color image data is issued on the personal computer 101 by a user's input operation, the color image data is stored in a printer driver (not shown) stored in the personal computer 101. ) Is sent to the software. The printer driver converts the color image data into a data format that the printer controller 4 can interpret,
The color image data is sent to the input interface 105 inside the printer controller 4. The color image data received by the printer controller 4 is temporarily stored in the reception buffer area 6 of the RAM 3.

Next, the microprocessor 106 sets R
The color image data held in the reception buffer area 6 is read out according to the program stored in the OM 2, and the banding-compatible display list area 7 in the RAM 3 is read out.
Develop as a display list. At this time, a list is generated as a banding-compatible display list while one page of printing paper is divided into α bands (band-wise display list generating means). When the display list corresponding to the banding is generated, the microprocessor 106 sequentially reads the display list in band units from the printing start band, and rasterizes the raster data in the band buffer areas 8c, 8m, 8y, and 8k for each color ( Band raster data conversion means).

Next, each band buffer area 8c, 8
Correction is performed on the m, 8y, and 8k raster data. In the first embodiment, as described above, the skew / position shift of cyan is detected by the skew / magnification detecting unit 111, and the skew / position shift is detected in magenta, yellow, and black. Not been. Therefore, the raster data developed in the band buffer area 8c is corrected, and the other band buffer areas 8c are corrected.
The raster data of m, 8y, and 8k is sent to the printer engine 103 as it is.

Next, the data developed in each band buffer area is transmitted to the printer engine 103.

As shown in FIG. 3, the correction operation for raster data expanded in the band buffer area 8c is performed to correct the skew of the printer engine 5 for raster data of bands n and n + 1 which have already been expanded. As shown by a parallelogram indicated by a dotted line in the middle, raster data in an area (including a part of (n + 1)) skewed at an angle opposite to the skew direction of the printer engine 5 is read and transferred to the printer engine 5. (Skew / magnification correction means). Here, since the band buffer 8c holds three bands of band raster data, it is possible to output raster data corresponding to a part of n + 1. FIG.
In (b), the same operation as in FIG. 3 (a) is repeated. By performing the above operation for each band, the raster data can be transferred to the printer engine while performing the correction, so that the skew correction can be easily realized.

Although only the skew correction has been described above, even in the case where magnification correction is further performed, a further scaling function (no need for precision) is required when data is sent to the printer engine 10 while performing the above-described operations. In this case, the operation is realized by inflating and thinning out the data, and when accuracy is required, the magnification is adjusted while complementing the data.

In order to correct temporal continuity of data caused by hardware-based intermittent reading by skew reading and increase / decrease of data amount by performing magnification correction, a buffer memory such as a FIFO is usually used. Although it may be necessary, it is not shown.

In the configuration described in the first embodiment, the microprocessor 3 reads the display list in band units and expands the raster data in the band buffer. It is also conceivable that the configuration is replaced with, for example. Further, as the band buffer areas 8c, 8m, 8y, and 8k, a memory different from the memory having the reception buffer area 6 and the banding-compatible display list area 7 may be used. In any case, as shown in the first embodiment, when raster data is expanded in band units, at least three or more band buffers are provided so that the controller can correct the skew and magnification of the engine while the printer engine performs correction. All the configurations for sending the corrected data to are included in the present invention.

In the first embodiment, the tandem-type printer engine for four-color printing has been described.
A tandem-type printer engine that handles the above colors can be similarly implemented. In the first embodiment, a toner-type printer engine is described. However, a plurality of line-type ink-jet printer engines can be similarly implemented.

As described above, the skew correction and the magnification correction conventionally performed by the printer engine can be easily performed on the printer controller 9 side.

[0045]

As described above, according to the present invention, the skew / magnification correction is performed on the raster data generated by the printer controller, and then the corrected raster data is transmitted to the printer engine. Accordingly, it is possible to reduce the number of circuits and memories for skew correction and magnification correction on the printer engine side, and it is possible to provide a tandem-type color printer device having a simple configuration.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of a tandem-type image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an example of a document according to the first embodiment of the present invention.

FIG. 3A is a diagram showing a state of a band buffer during raster data development operation on the (n + 2) th band according to the first embodiment of the present invention. (B) A raster data development operation is performed on the n + 3 band in the first embodiment of the present invention. State diagram of the band buffer

FIG. 4 is a functional block diagram of a conventional tandem image forming apparatus.

FIG. 5 is a configuration diagram of a general image forming mechanism.

6A is a diagram illustrating a positional shift in a transfer material moving direction. FIG. 6B is a diagram illustrating a positional shift in a scanning direction. FIG. 6C is a diagram illustrating a positional shift in an oblique direction. (E) Diagram showing deviation of bending error

[Explanation of symbols]

 Reference Signs List 1 tandem image forming apparatus 2 ROM 3 RAM 4 printer controller 5 printer engine 6 reception buffer area 7 display list area corresponding to banding 8c, 8m, 8y, 8k band buffer area 21c, 21m, 21y, 21k image station 22c, 22m, 22y, 22k Photoconductors 23c, 23m, 23y, 23k Chargers 24c, 24m, 24y, 24k Developing Units 25c, 25m, 25y, 25k Cleaning Units 26c, 26m, 26y, 26k Exposure Units 27 Transfer Units 28c, 28m, 28y, 28k transfer unit 29c, 29m, 29y, 29k exposure unit 30, 31 drive roller 32 intermediate transfer belt 33 control unit 34 paper feed cassette 35 sheet material 36 paper feed roller 37 sheet material transfer roller 38 fixing device 38a heating roller 10 DESCRIPTION OF SYMBOLS 1 Personal computer 102 Printer controller 103 Printer engine 104 Tandem type image forming apparatus 105 Input interface 106 Microprocessor 107 ROM 108 RAM 109 Engine interface 110 Line memory 111 Skew / magnification detecting means 112 Skew / magnification correction coefficient calculating means 113 Skew / magnification correction Means 114 Image Forming Mechanism

Continued on the front page F term (reference) 2C087 AA15 AB05 AB08 AC07 AC08 BC02 BC05 BD12 BD13 BD24 2C262 AA02 AA05 AA24 AB15 AC07 EA04 EA06 FA06 GA04 GA09 GA13 2H030 AD11 5B021 AA01 AA02 DD13 LB07 LG07 LL05 9A001 H42H

Claims (1)

[Claims] 1. An image formed by an n-color toner or ink is m
A printer controller for generating image data of a tandem image forming apparatus for forming a divided image for each color by image forming means (1 <m ≦ n) and superimposing n colors to form a composite image; A band-unit display list generating means for generating a band-unit display list, which is a band-unit drawing list, while dividing image data for one page of printing received via the printer into α bands in the printing sub-scanning direction; Band raster data conversion means for converting the unit display list into band raster data, which is raster data in band units, while reading the display list in band units; and mechanical and optical accuracy of m image forming means for the band raster data. Skew and magnification correction means for correcting relative distortion such as skew and magnification caused by
a band buffer memory for holding the band raster data for three or more bands for each of the m image forming units.