JP2008306247A - Image processing apparatus and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processing apparatus and method in which mirror reversal processing and top-and-bottom reversal processing can be carried out at high speed without adding a hardware resource such as a dedicated mirror reversal portion or a top and bottom reversal portion and without using a dedicated memory. <P>SOLUTION: The apparatus includes a memory 310 having an area 320 for storing the raster data of a print image, an address control section (compression address control section 314) for generating the read-out address of the raster data stored in the raster data storage area 320 at least depending on the need of skew correction and other process execution, and a section 306 for reading out the raster data according to the read-out address generated by the read-out address control section and performing a predetermined compression processing. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image processing apparatus such as a color copying machine, a color printer, and a color facsimile employing an electrophotographic process, and an image processing method for image data to be input.

  When copying or printing with an electrophotographic printer or multifunction printer, image data read by a scanner or digital still camera, print data input from a personal computer, or fax received image data is converted to raster data. Then, copy processing and print processing are realized through processes such as toner image formation, paper transfer, and toner fixing based on the raster data.

  In this electrophotographic image forming apparatus, it is known that a skew (SKEW) occurs due to an accuracy error in assembling an image recording unit or the influence of heat in the image forming apparatus.

  20A, 20B, and 20C are explanatory diagrams showing the state of the print line when skew occurs on the printing paper and after skew correction.

  In the image forming apparatus, a print line is formed by performing optical scanning in the main scanning direction. However, as shown in FIGS. The print lines recorded in the above are shifted in the sub-scanning direction, and so-called skew occurs.

  Therefore, the skew can be corrected as shown in FIG. 20C by shifting each pixel constituting the print line by a predetermined amount in the sub-scanning direction.

  FIGS. 21A and 21B are explanatory diagrams showing the state of the print line when skew occurs in the color image forming apparatus and after skew correction.

  With colorization of print images, for example, in a tandem type image forming apparatus in which four color image recording units of cyan, yellow, magenta, and black are arranged in a row, not only skew with respect to print paper but also FIG. There is also a skew caused by the relative inclination when forming each color image as shown in FIG.

  In an image forming apparatus that forms a color image by superimposing a plurality of single color images, for example, the pixels constituting each of the cyan, magenta, and yellow print lines are shifted in the sub-scanning direction with reference to the black print line. The skew can be corrected as shown in FIG.

  With respect to such skew at the time of image formation, for example, Patent Document 1 discloses a raster data skew correction method. The technique disclosed in (Patent Document 1) not only performs skew correction, but also eliminates the need for a line memory for skew correction by performing skew correction before transmitting raster data to the image forming apparatus. By compressing and storing the skew-corrected raster data, the memory usage efficiency is improved.

  By the way, in recent years, due to environmental considerations, opportunities for printing and copying on both sides of printing paper are increasing. However, when performing double-sided printing, the direction of printing on the front and back sides is 180 degrees opposite due to the convenience of paper transport. Therefore, a function for reversing the image data upside down is required. Further, when the image is copied on a special sheet and then heated and transferred to a T-shirt or the like with an iron, a mirror inversion function of the image is required.

  FIG. 22 is a configuration diagram of an image processing apparatus configured to be able to execute a skew correction in combination with top and bottom inversion and mirror inversion using a conventional technique.

  If the technique disclosed in the above-mentioned (Patent Document 1) is used to execute a combination of mirror reversal and top-and-bottom reversal processing for skew correction, a configuration as shown in FIG. 22 is obtained.

  In FIG. 22, 100 is a memory, 101a is a copy image processing unit, 101b is a print image processing unit, 102 is an interface unit, 103 is a CPU, 106 is a mirror reversing unit, 108 is a top / bottom reversing unit, 110 is a skew correcting unit, 112 Is a data compression unit, and 114 is a data decompression unit. Further, in the memory 100, a raster data storage area 115, a data storage area 116 after mirror inversion processing, a data storage area 117 after top and bottom inversion processing, a data storage area 118 after skew correction processing, and a compressed data storage area 119 are stored. Is assigned.

  An image image (scan data) read by a scanner, a digital camera, or the like is subjected to, for example, RGB to CMYK color conversion processing or print γ correction processing by the copy image processing unit 101a, and a raster data storage area in the memory 100 115 is stored. Also, print data input via the interface 102 from a personal computer (not shown) outside the apparatus is subjected to image processing by the print image processing unit 101b and rasterization processing by the CPU 103 or the like, and similarly stored as raster data. Stored in area 115.

  If the image stored in the raster data storage area 115 is expressed by the letter F shown in FIG. 7 (r), the mirror inversion unit 106 performs mirror inversion, and the data stored in the data storage area 116 after the mirror inversion processing is the same. As shown in FIG. Further, when the data that has been subjected to the mirror inversion process is inverted by the upside-down inversion unit 108, the data stored in the data storage area 117 after the upside-down inversion process is as shown in FIG. Further, when the skew-corrected data is skew-corrected by the skew correction unit 110, the data stored in the data storage area 118 after the skew correction processing is as shown in FIG.

As described above, in order to realize the mirror inversion processing, the top inversion processing, and the skew correction processing, respective dedicated processing circuits are required. In addition, a memory used by each dedicated processing circuit is required.
JP 2000-246965 A

  However, according to the above-described conventional configuration, the circuit scale is increased by adding the mirror inversion unit and the top / bottom inversion unit to the skew correction unit, and an extra working memory is required for performing the mirror inversion processing and the top / bottom inversion processing. become. Furthermore, a problem such as a delay in operation time due to an increase in processing occurs. In addition, the skew correction process, the mirror inversion process, and the upside down process cannot be performed at the same time.

  The present invention solves the above-described conventional problems, and in an image processing apparatus that executes at least skew correction processing, there is no need to add hardware resources such as a dedicated mirror reversing unit or top / bottom reversing unit, and a dedicated memory It is an object of the present invention to provide an image processing apparatus and an image processing method capable of executing mirror inversion processing and top-to-bottom inversion processing at high speed without using the.

  In order to solve the above problems, an image processing apparatus according to the present invention stores a raster data storage memory that stores raster data of a print image, and raster data storage according to whether or not at least skew correction processing and other processing need to be performed. A read address control unit that generates a read address for raster data stored in a memory, and a compression unit that reads raster data in accordance with the read address generated by the read address control unit and performs a predetermined compression process. is there.

  According to the image processing apparatus and the image processing method of the present invention, it is possible to simultaneously perform other processing such as skew correction, mirror inversion processing, and top-to-bottom inversion processing, and as a result, the processing speed can be increased. . Further, the scale of the processing circuit can be reduced, and the memory capacity used can be further reduced.

  An image processing apparatus according to the present invention includes a raster data storage memory for storing raster data of a print image, and raster data stored in the raster data storage memory according to whether or not at least skew correction processing and other processing are necessary. A read address control unit that generates a read address and a compression unit that reads raster data and performs a predetermined compression process according to the read address generated by the read address control unit are provided.

  This makes it possible to simultaneously perform skew correction and other processing, and as a result, increase the processing speed. Further, the scale of the processing circuit can be reduced, and the memory capacity used can be further reduced.

  According to the present invention, the other processes are at least one of a mirror inversion process that inverts the left and right sides of the print image and an upside down process that inverts the top and bottom of the print image.

  As a result, skew correction, mirror inversion processing, and upside down processing can be performed simultaneously, and as a result, the processing speed can be increased. Further, the scale of the processing circuit can be reduced, and the memory capacity used can be further reduced.

  The image processing apparatus of the present invention also includes a raster data storage memory that stores raster data of a print image, a read address control unit that generates a read address of raster data stored in the raster data storage memory, and the read address control. The raster data is read in accordance with the read address generated by the unit, a predetermined compression process is performed, a compressed data storage memory that stores data compressed by the compression unit, and the compressed data storage memory A decompression unit that reads data and performs decompression processing, and a data output unit that outputs raster data decompressed by the decompression unit to the image forming apparatus, and the read address control unit corrects the skew of the image forming apparatus. A skew correction unit that generates a read address and a print image A mirrored portion that generates a read address so as to reverse the right and left, which is constituted of the upper and lower printed image in a vertical reversing unit for generating a read address to vertical.

  With this configuration, skew correction, mirror inversion, and top-to-bottom inversion processing can be performed simultaneously depending on the address control method for reading data from the memory when raster data is compressed, so an image processing device that does not require a dedicated circuit for such processing Can be provided. In addition, since simultaneous processing is performed, it is possible to provide an image processing apparatus capable of speeding up processing.

  The image processing apparatus of the present invention also includes a raster data storage memory that divides raster data of a print image into several regions in the sub-scanning direction of printing and stores the data for each band, and a raster stored in the raster data storage memory. A read address control unit that generates a data read address, a compression unit that reads raster data in accordance with the read address generated by the read address control unit and performs a predetermined compression process for each band, and a band for each band by the compression unit A compressed data storage memory for storing the compressed data for each band, a print order storage unit for storing information indicating the print order of the compressed data for each band, and a print order recorded by the print order storage unit, A decompression unit that reads the compressed data from the compressed data storage memory for each band and performs decompression processing; and A data output unit that outputs raster data decompressed by the decompression unit to the image forming apparatus, a read address control unit, a skew correction unit that generates a read address so as to correct skew of the image forming apparatus, and a print image The mirror inversion unit that generates a read address so as to invert the left and right, and the top and bottom inversion unit that generates a read address so that the top and bottom of the print image are upside down.

  With this configuration, skew correction, mirror inversion, and top-to-bottom inversion processing can be performed simultaneously depending on the address control method for reading data from the memory when raster data is compressed, so an image processing device that does not require a dedicated circuit for such processing Can be provided. In addition, since the configuration allows processing for each band, especially when the upside down processing is specified, skew correction is performed sequentially each time raster data is input in units of bands without having to store one page of raster data before compression. Thus, it is possible to provide an image processing apparatus that can reduce the memory required for processing by performing mirror inversion and top-and-bottom inversion simultaneously. In addition, since simultaneous processing is performed, it is possible to provide an image processing apparatus capable of speeding up processing.

  In the present invention, the raster data storage memory and the compressed data storage memory are configured to share the same memory.

  As a result, the amount of work memory used for image processing can be reduced.

  In the present invention, the compression unit and the expansion unit are configured to operate simultaneously in parallel.

  Thereby, the throughput of the entire image processing can be increased.

  In the present invention, raster data is binary image data. As a result, for example, binary image data sent from a personal computer or the like outside the image processing apparatus can be processed at high speed.

  In the present invention, raster data is multi-value image data. Thereby, for example, multi-value image data sent from a scanner or a digital camera can be processed at high speed.

  The image processing method of the present invention stores raster data of a print image in a memory, and generates a read address of raster data stored in the memory at least according to the necessity of execution of skew correction processing and other processing. The raster data is read according to the generated read address and subjected to a predetermined compression process.

  This makes it possible to simultaneously perform skew correction and other processing, and as a result, increase the processing speed.

  In the image processing method of the present invention, raster data of a print image is stored in a memory, read address control of the memory is performed, raster data specified by the controlled address is read, and the read raster data is predetermined. The data compressed by the compression process is stored in the memory, the compressed data is read from the memory, the decompression process is performed, and the raster data decompressed by the decompression process is output to the image forming apparatus. In the processing method, read address control when performing predetermined compression processing includes read address control for correcting the skew of the image forming apparatus, read address control for inverting the left and right of the print image, and top and bottom of the print image. Address control that combines at least one of the read address controls It is obtained so as to generate.

  This makes it possible to simultaneously perform skew correction, mirror inversion, and top-to-bottom inversion, depending on the address control method for reading data from the memory during raster data compression, and since these are processed simultaneously, image processing is extremely fast. Can be executed.

  Hereinafter, embodiments of the present invention will be described in detail using a color image forming apparatus as an example.

  In addition, this invention is not limited to the individual specific aspect as an apparatus, It can implement as a method backed by description of embodiment, The content shown in embodiment is created so that execution is possible It is also possible to implement the program by using a program.

(Embodiment 1)
FIG. 1 is an explanatory diagram showing connections between the multifunction device of Embodiment 1 of the present invention and its external devices.

  In the first embodiment, the printing unit 205 of the multi-function device 200 constitutes a so-called electrophotographic apparatus.

  As shown in FIG. 1, the multi-function device 200 includes an interface unit 201 that receives image data from an external device (for example, a personal computer 206 and a digital camera 207) and a FAX line 208, a scanner unit 202 that reads an image, and a printing unit. 205 and a control unit 203 that controls them. The flow of image data when printing is performed by the multi-function device 200 is that image data sent from a personal computer 206 or a digital camera 207 as an external device is received through the interface unit 201, and the image forming apparatus according to the present invention is used. After the image processing is performed by the data processing unit 204, which is an example, the image is formed by the printing unit 205. In addition, the flow of data when copying is executed by performing image processing on the scan data read by the scanner unit 202 by the data processing unit 204 and then performing image formation by the printing unit 205.

  FIG. 2 is a schematic configuration diagram of the data processing unit 204 of the multifunction device 200 according to Embodiment 1 of the present invention.

  As shown in FIG. 2, image data input from the above-described external device or scanner unit 202 (see FIG. 1) passes through a receiving unit 301, and then a copy image processing unit 302 for scan data or a print for print language data. Data processing is performed by the processing unit 303, the digital camera image processing unit 304, the FAX processing unit 305, and the like, and finally converted into raster data used for image formation in the printing unit 205.

  For the purpose of temporarily storing such raster data in the memory 310, the compression unit 306 often performs data compression, and the raster data once compressed and stored in the memory 310 is stored in the decompression unit 307 in the original raster data. And is sent to the printing unit 205 via the data transmission unit 308.

  Here, the encoding method of the still image used in the compression unit 306 shown in Embodiment 1 is not particularly limited. For example, a commonly known encoding scheme such as JPEG, JBIG, MH, MR, MMR, etc. may be used, or a uniquely devised encoding scheme may be used. Also, it has a plurality of encoding methods, and the type of image data input to the compression unit 306, that is, output data of the copy image processing unit 302, output data of the print processing unit 303, output data of the digital camera image processing unit 304, The encoding method may be switched according to the output data of the FAX processing unit 305. The decompression unit 307 uses a decoding method that matches the coding method of the compression unit 306.

  FIG. 3 is a configuration diagram of the printing unit 205 of the multi-function device 200 according to Embodiment 1 of the present invention.

  The printing unit 205 according to the first embodiment applies an electrophotographic process, and the printing unit 205 sequentially forms images of four colors of cyan, magenta, yellow, and black as shown in FIG. ) It is a tandem type.

  Hereinafter, the image forming process in the printing unit 205 according to the first embodiment will be described in more detail.

  The printing unit 205 executes image formation by forming latent images on the photoconductors 2a, 2b, 2c, and 2d, which are image carriers, in accordance with the raster data sent from the data processing unit 204 described above.

  As shown in FIG. 3, the printing unit 205 includes four image forming stations 1a, 1b, 1c, and 1d. The image forming stations 1a, 1b, 1c, and 1d are photoconductors 2a and 2b as image carriers. 2c and 2d, and charging means 3a, 3b, 3c and 3d for uniformly charging the surface of each photosensitive drum, and developing means 4a for visualizing the electrostatic latent image. 4b, 4c, 4d, cleaning means 5a, 5b, 5c, 5d for removing residual toner, and scanning optical system exposure for irradiating each photoconductor 2a, 2b, 2c, 2d with light according to image information Means 6a, 6b, 6c, 6d and transfer means 8a, 8b, 8c, 8d for transferring the toner image to the intermediate transfer belt 12 constituting the transfer means 7 are arranged, respectively.

  Here, a yellow image, a magenta image, a cyan image, and a black image are formed at the image forming stations 1a, 1b, 1c, and 1d, respectively, and the yellow image, the magenta image, and the cyan image are formed from the exposure units 6a, 6b, 6c, and 6d, respectively. Then, exposure light 9a, 9b, 9c, 9d, which is scanning light corresponding to the black image, is output.

  An endless belt-like intermediate transfer belt 12 supported by rollers 10 and 11 is disposed below the photoreceptors 2a, 2b, 2c, and 2d in a manner that passes through the image forming stations 1a, 1b, 1c, and 1d. And rotate in the direction of arrow A.

  Further, pattern detection means 14 is provided for forming an image on the intermediate transfer belt 12 for detecting a resist (formation position) for each color and detecting the pattern.

  The sheet material 17 such as printing paper stored in the paper feed cassette 16 is fed by a paper feed roller 18 and is discharged to a paper discharge tray (not shown) through a transfer roller 19 and a fixing device 20. .

  In the printing unit 205 configured as described above, first, in the image forming station 1d, black component color as image information is formed on the photosensitive drum 2d by a known electrophotographic process unit using the charging unit 3d and the exposure unit 6d. A latent image is formed. Thereafter, the developing unit 4d visualizes the black toner image with a developer having black toner, and the transfer unit 8d transfers the black toner image to the intermediate transfer belt 12.

  On the other hand, while the black toner image is being transferred to the intermediate transfer belt 12, a cyan component color latent image is formed at the image forming station 1c, and the cyan toner image of the cyan toner is visualized by the developing means 4c. This is transferred by the transfer means 8c and superimposed on the black toner image previously transferred onto the intermediate transfer belt 12.

  Thereafter, image formation is similarly performed for the magenta toner image and the yellow toner image, and when the four color toner images are superimposed on the intermediate transfer belt 12, the paper is fed from the paper feed cassette 16 by the paper feed roller 18. A four-color toner image is transferred and transported collectively onto a sheet material 17 such as paper by a transfer roller 19 and heated and fixed by a fixing device 20, and a full-color image is obtained on the sheet material 17.

  The respective photoreceptors 2a, 2b, 2c, and 2d that have been transferred have the residual toner removed by the cleaning means 5a, 5b, 5c, and 5d, and are prepared for the next subsequent image formation, thereby completing the printing operation. .

  Since the printing unit 205 having such a tandem type configuration includes the image forming stations 1a to 1d in which an image forming process is executed for each color, it is advantageous for speeding up printing. However, there is a problem in how well the registration (registration) of the images formed in the different image forming stations 1a to 1d is performed. This is because the shift in the image forming positions of the four colors transferred to the sheet material 17 finally appears as a positional shift or a change in color tone.

  In particular, the positional deviation in the oblique direction (hereinafter referred to as “skew error” or simply “skew”) as shown in FIG. 21A is a problem peculiar to the tandem configuration, and FIG. As shown in FIG. 21, it is effective to correct the print image data in advance so that the inclination of one color (black reference in FIG. 21) and the other colors (cyan, yellow, magenta in FIG. 21) are matched.

  The amount to be corrected (shift amount) at this time is a reference pattern (resist pattern) transmitted from the data processing unit 204 in advance, and a toner image is formed on the intermediate transfer belt 12 in the printing unit 205. Correction data corresponding to the amount to be corrected can be obtained based on the detection result obtained by detecting the inclination of each toner image by the pattern detection means 14.

  FIG. 4 is a configuration diagram showing the configuration of each functional block of the data processing unit 204 according to Embodiment 1 of the present invention, and shows the configuration of the data processing unit 204 shown in FIG. 2 in more detail.

  FIG. 5 is an explanatory diagram for explaining a process of skew correction processing and mirror inversion processing executed by the data processing unit 204 according to Embodiment 1 of the present invention.

  Hereinafter, operations of the skew correction process and the mirror inversion process performed after detecting the inclination of each toner image will be specifically described with reference to FIGS. 4 and 5.

  Here, reference numeral 310 denotes a memory that temporarily stores image data and stores variables handled by the CPU 313. The compression address control unit 314 that generates the data read address and write address of the compression unit 306 includes a mirror inversion address control unit 315, a skew correction address control unit 316, and an upside down address control unit 317.

  Scan data and print data input to the receiving unit 301 are subjected to data processing by the copy image processing unit 302 and the print processing unit 303 as necessary, and finally stored in the memory 310 as raster data. Here, the copy image processing unit 302 and the print processing unit 303 are inserted between the receiving unit 301 and the memory 310 for convenience, but the configuration may be changed as appropriate depending on the flow of data processing and the presence or absence of software processing. Absent.

  Hereinafter, a case where the skew correction process is executed alone will be described.

  The skew correction address control unit 316 controls the read address of the memory 310 according to the “amount to be corrected (deviation amount)”, thereby rearranging the image data in the direction opposite to the deviation direction due to the skew. For this purpose, printing of the rearranged data can cancel the image misalignment.

  Here, it is assumed that when the raster data shown in FIG. 5A is printed without skew correction, the image forming apparatus is in a state in which a skew error in the upper right direction for two pixels occurs. The skew direction and shift amount of the image forming apparatus are determined based on values measured in advance, and the skew correction address control unit 316 shifts the data shown in FIG. To give instructions. The memory address output from the compression address control unit 314 is controlled so as to read the raster data in accordance with the order of L1 to L20 and the direction of the arrow, and the data compressed by the compression unit 306 is stored in the compressed data storage area 321.

  After at least one page of compressed data has been prepared (the compression process may be in progress if the compression process can be performed at a high speed that can follow the print throughput), the decompression unit 307 generates address information generated by the decompression address control unit 318 ( In accordance with the compression rule, the decompressed image data is read out from the compressed data storage area 321 in accordance with the image data after decompression, and the compressed data is decompressed. The decompressed raster data is transmitted to the printing unit 205 by the data transmission unit 308. Here, the arrangement of the data after being decompressed by the decompression unit 307 is shifted to the lower right direction by two pixels (shift correction processing) as shown in FIG. The result of printing is an image subjected to skew correction processing.

  Next, an address generation operation by the mirror inversion address control unit 315 and the skew correction address control unit 316 shown in FIG. 4 will be described with reference to FIGS. 5C and 5D.

  Here again, it is assumed that when the raster data shown in FIG. 5C is printed without skew correction, the image forming apparatus is in a state in which a skew error in the upper right direction for two pixels occurs. The skew direction and shift amount of the image forming apparatus are determined based on values measured in advance, and the skew correction address control unit 316 shifts the data shown in FIG. To give instructions. The mirror inversion address control unit 315 instructs the compression address control unit 314 to reverse the reading direction of the raster data in the main scanning direction. The memory address output from the compression address control unit 314 is controlled so as to read raster data in accordance with the order of L1 to L20 and the direction of the arrow, and the data compressed by the compression unit 306 is stored in the compressed data storage area 321.

  After at least one page of compressed data has been prepared (the compression process may be in progress if the compression process can be performed at a high speed that can follow the print throughput), the decompression unit 307 generates address information generated by the decompression address control unit 318 ( In accordance with the compression rule, the decompressed image data is read out from the compressed data storage area 321 in accordance with the image data after decompression, and the compressed data is decompressed. The decompressed raster data is transmitted to the printing unit 205 by the data transmission unit 308. Here, the arrangement of the data after decompression by the decompression unit 307 is an arrangement in which two pixels are shifted diagonally downward to the right as shown in FIG. 5D (shift correction processing), and the left and right sides of the image are mirrored. Since the arrangement is reversed, the result of printing by the printing unit 205 is an image in which skew correction processing and mirror inversion processing are performed simultaneously.

  FIG. 6 is an explanatory diagram for explaining the process of skew correction processing, top / bottom inversion processing, and mirror inversion processing executed by the data processing unit 204 according to Embodiment 1 of the present invention.

  The address generation operation by the upside down address control unit 317 and the skew correction address control unit 316 shown in FIG. 4 will be described with reference to FIGS. 6 (a) and 6 (b).

  Here again, it is assumed that when the raster data shown in FIG. 6A is printed without skew correction, the image forming apparatus is in a state where a skew error in the upper right direction for two pixels occurs. The skew direction and shift amount of the image forming apparatus are determined based on values measured in advance, and the skew correction address control unit 316 shifts the data shown in FIG. To give instructions. In addition, the upside down address control unit 317 instructs the compression address control unit 314 to reverse the raster data reading direction in the sub-scanning direction. The memory address output from the compression address control unit 314 is controlled so as to read raster data in accordance with the order of L1 to L20 and the direction of the arrow, and the data compressed by the compression unit 306 is stored in the compressed data storage area 321.

  After at least one page of compressed data has been prepared (the compression process may be in progress if the compression process can be performed at a high speed that can follow the print throughput), the decompression unit 307 generates address information generated by the decompression address control unit 318 ( In accordance with the compression rule, the decompressed image data is read out from the compressed data storage area 321 in accordance with the image data after decompression, and the compressed data is decompressed. The decompressed raster data is transmitted to the printing unit 205 by the data transmission unit 308. Here, the arrangement of the data after decompression by the decompression unit 307 is an arrangement in which two pixels are shifted diagonally downward to the right (shift-corrected) as shown in FIG. Since the arrangement is reversed, the result of printing by the printing unit 205 is an image in which the skew correction process and the upside down process are performed simultaneously.

  Further, the address generation operation by the top and bottom inversion control unit 317, the mirror inversion address control unit 315, and the skew correction address control unit 316 shown in FIG. 4 will be described with reference to FIGS. 6C and 6D.

  Here again, it is assumed that the image forming apparatus is in a state in which a skew error in the diagonally upward direction for two pixels occurs when raster data shown in FIG. 6C is printed without skew correction. The skew direction and shift amount of the image forming apparatus are determined based on values measured in advance, and the skew correction address control unit 316 shifts the data shown in FIG. To give instructions.

  Further, the mirror inversion address control unit 315 issues an instruction to the compression address control unit 314 so that the reading direction of the raster data in the main scanning direction is reversed. The upside down address control unit 317 instructs the compression address control unit 314 to reverse the reading direction of the raster data in the sub-scanning direction. The memory address output from the compression address control unit 314 is controlled so as to read the raster data in accordance with the order of L1 to L20 and the direction of the arrow, and the data compressed by the compression unit 306 is stored in the compressed data storage area 321.

  After at least one page of compressed data has been prepared (the compression process may be in progress if the compression process can be performed at a high speed that can follow the print throughput), the decompression unit 307 generates address information generated by the decompression address control unit 318 ( In accordance with the compression rule, the decompressed image data is read out from the compressed data storage area 321 in accordance with the image data after decompression, and the compressed data is decompressed. The decompressed raster data is transmitted to the printing unit 205 by the data transmission unit 308. Here, the arrangement of the data after decompression by the decompression unit 307 is an arrangement in which two pixels are shifted diagonally downward to the right as shown in FIG. 5B (shift correction processing), and the left and right sides of the image are mirrored. Since the arrangement is reversed, the result of printing by the printing unit 205 is an image in which skew correction processing, upside down processing, and upside down processing are performed simultaneously.

  As described above, in FIG. 5 and FIG. 6, the final compressed address control unit 314 is operated by a part or all of the skew correction address control unit 316, the mirror inversion address control unit 315, and the upside down address control unit 317. We explained how the output address changes.

  As described above, the image processing apparatus according to the first embodiment includes a raster data storage memory (memory 310 having or defined the raster data storage area 320) that stores raster data of a print image, at least skew correction processing, and other processing. A read address control unit (compressed address control unit 314) that generates a read address of raster data stored in the raster data storage memory according to necessity of execution of processing, and a read address generated by the read address control unit And a compression unit 306 that reads raster data and performs a predetermined compression process.

  Hereinafter, the generation process of the output address of the compressed address control unit 314 that realizes the above-described operation will be described with reference to FIGS.

  FIG. 7 is an explanatory diagram showing addresses output from the compressed address control unit 314 in Embodiment 1 of the present invention.

  FIG. 7A shows the address of the memory in which 100 pixels (N = 100) in total of 10 pixels of main scanning (number of main scanning pixels M = 10) and 10 pixels of sub scanning are stored. The upper left is address 0 and the lower right is address 99. In most cases, the memory address where data is actually stored is an address to which an offset address (for example, offset address 10000) is added, but the offset address is ignored for the sake of simplicity.

  In the following description, multi-value image data having a data amount of, for example, 8 bits / pixel is assumed as image data. That is, one pixel (multi-valued image data) is designated by one address generated by the compressed address control unit 314.

  S shown in FIG. 7A is a start address, which is an initial value of the address generation processing of the compressed address control unit 314.

  p1 and p2 respectively represent a first skew correction point and a second skew point, and both represent the distance (number of pixels) from the left end of the memory space expressed as shown in FIG.

  FIG. 7B shows the stored memory address of N = 100 pixels and the image data “F”, and the compressed address generator 314 sets the memory address in the direction of the arrows L1 to L12. Occurs and the compression unit 306 reads the data. Here, after the distance to the change point, that is, after passing through the first skew correction point p1 and the second skew point p2, as shown in FIG. 5 and FIG. 6, an operation of shifting the read pixel is performed to perform skew correction. However, as shown in FIG. 7B, this includes an operation of returning the address value by one step in the sub-scanning direction (decreasing the address value).

  FIG. 7C shows a state in which the data is rearranged at the part where the arrow in FIG. 7B is broken and the data is rearranged. As a result of the rearrangement, the image of the image data “F” is skewed downward. Indicates that data can be generated.

  FIG. 8 is a flowchart showing the operation of the compressed address control unit 314 in Embodiment 1 of the present invention.

  FIG. 9 is an explanatory diagram illustrating a process in which the skew correction process, the top / bottom inversion process, and the mirror inversion process are executed according to the address output from the compressed address control unit 314 according to the first embodiment of the present invention.

  Hereinafter, a specific example of address generation will be described using the flowchart of FIG. 8 together with FIGS.

  In FIG. 8, S is the start address already described, and indicates the initial value of the address generation process. B is the start address of raster data, E is the final address of raster data, M is the number of main scanning pixels, N is the total number of pixels, p1 is the distance to the first skew correction point, and p2 is the distance to the second skew correction point. , I is a main scanning counter, j is a sub-scanning counter, k is a pixel counter, r is an address variable, x is a scanning direction of the main scanning (1: scanning right, -1: scanning left), y is sub-scanning The scanning direction (1: scanning down, -1: scanning up), z is the skew correction direction (1: right upward direction, -1 right downward direction), and Ad is the output address value.

  In the example of FIG. 7, B = 0, E = 99, M = 10, p1 = 4, p2 = 7, N = 100, x = 1, y = 1, and z = −1. A flowchart will be described.

  First, in step 1, variables j and k are initialized to 0, and an initial value for address generation processing is input to S. In the case shown in FIG. 7B, S = 0.

  Next, in step 2, the initial value S of the address generation process is entered in the address variable r (since j is 0, the calculated value of r becomes S), and then the main scanning counter i is reset to 0.

  In step 3, the pixel count k is incremented, and the process ends when the count value exceeds the total number N of pixels.

  In step 4, it is determined whether or not the skew correction point p1 or p2 has been passed. If it has passed, the address is changed by one line. Since the value of z is -1, the address is returned by one line.

  In step 5, it is confirmed whether the address variable r is an address in the data area (addresses 0 to 99). If it is out of the range, the process jumps to step 7.

  In step 6, the value of the address variable r is entered in the address output Ad to determine the address of the data to be compressed. After that, x is added to the address variable, but since the value of x is 1, the address is changed in the increasing direction.

  In step 7, the main scanning counter i is incremented, and if the counter value is less than M, the process returns to step 3. When it becomes equal to M, the sub-scanning counter j is incremented as shown in Step 8 and the process returns to Step 2. When j is incremented, the raster data represents a line feed.

  According to the above flowchart, the address output from the compressed address control unit 314 has the value shown in FIG.

  In the flowchart shown in FIG. 8, B = 0, E = 99, M = 10, p1 = 4, p2 = 7, N = 100, x = 1, y = 1, z = 1, and the initial address generation processing. Assuming that the value S is the pixel address two lines before the upper left pixel, that is, S = −20 as shown in the left side of FIG. 9A, addresses are generated in order from L1 to L12, and the image data is rearranged. 9 (a) The image shown on the right side. This image shows that skew correction data in the direction opposite to that in FIG. 7C can be generated, and the sign of z controls the direction of skew correction.

  In the flowchart of FIG. 8, B = 0, E = 99, M = 10, p1 = 3, p2 = 6, N = 100, x = -1, y = 1, z = 1, and further address generation processing Is set to the pixel address two lines before the upper right pixel, that is, S = -11 as shown in the left side of FIG. 9B, addresses are generated in order from L1 to L12, and the image data is rearranged. And the image shown on the right side of FIG. This image shows that the image is mirror-inverted compared to FIG. 9A, and the sign of x controls the presence or absence of mirror inversion.

  In the flowchart of FIG. 8, B = 0, E = 99, M = 10, p1 = 4, p2 = 7, N = 100, x = 1, y = -1, z = -1, and further address generation The initial value S of processing is the pixel address after two lines of the lower left pixel, that is, S = 110 as shown in the left side of FIG. 9C, addresses are generated in the order of L1 to L12 in the figure, and the image data is When rearranged, the image shown on the right side of FIG. This image shows that the image is upside down compared to FIG. 9A, and the sign of y controls the presence / absence of upside down.

  In the flowchart of FIG. 8, B = 0, E = 99, M = 10, p1 = 3, p2 = 6, N = 100, x = -1, y = -1, z = 1, and further address generation The initial value S of processing is the address of the lower right pixel, that is, S = 99 as shown in the left side of FIG. 9D, addresses are generated in the order of L1 to L12 in FIG. When rearranged, the image shown on the right side of FIG. This image shows that the image is upside down as compared with FIG. 9A. By making both the sign of x and the sign of y negative, mirror inversion and upside down control are simultaneously performed. It shows that it is possible.

  In the flowchart of FIG. 8, the condition that there are two skew correction points is used for the sake of simplicity. However, even when there are a plurality of points, the concept is the same except that the condition of step 4 in the flowchart is increased. Note that the flowchart shown in FIG. 8 can be easily expressed in HDL (hardware description language), so that it can be easily realized in hardware.

  In the above description, the processing target is described as multi-valued image data. However, even in the case of binary data, the above description of the flowchart can be applied almost as it is. However, when mirror inversion processing is performed on binary image data, each bit corresponds to one pixel, and therefore processing for rearranging bits within one byte is added.

  As described above, in the first embodiment, the memory address is manipulated when the raster data is read. After the image processing in the copy image processing unit 302 or the print processing unit 303, the raster data is converted into the raster data. Even when the memory address is manipulated when writing to the storage area 320, the same effect can be obtained.

  The configuration described in the first embodiment has been described on the assumption that the printing unit 205 is a tandem type, but the present invention is also effective for a device in which the printing unit is configured only by a single color image forming process. . Although the first embodiment has been described based on the image forming apparatus using toner as the color material, the type of color material used for image formation or the scanning system for forming an image does not depart from the spirit of the present invention. Any device can be applied. For example, the printing unit 205 may be configured using a line-type inkjet head.

(Embodiment 2)
In the first embodiment, for example, when the top-and-bottom inversion process is executed, it is necessary to store one page of data in the raster data storage area 320 of the memory 310 shown in FIG. 4, but the image processing shown in the second embodiment The apparatus divides input raster data into several bands and processes each band to reduce the storage memory capacity.

  As described above, the first and second embodiments differ only in whether the unit for performing image processing is a page unit or a band unit, and data that is an example of the multifunction device 200 or the image processing device. The basic configuration of the processing unit 204 is the same. Therefore, the overlapping description is omitted.

  FIG. 10 is an explanatory diagram for explaining the data processing process of the data processing unit 204 in the second embodiment of the present invention.

  Hereinafter, with reference to FIG. 10, a process of simultaneously performing mirror inversion processing and top-to-bottom inversion processing while skew correcting input raster data in Embodiment 2 of the present invention will be described.

  The memory 310, the compression unit 306, and the decompression unit 307 in FIG. 10 have the same configuration as that shown in FIG. In order to simply explain the processing for each band, it is assumed that the input raster data is divided into four bands as shown on the left side of FIG.

  First, the first band (input band 1) of the input raster data is stored in the input buffer 1 of the memory 310. While the input raster data of the next band (input band 2) is stored in the input buffer 2 of the memory 310, the previously stored data in the input buffer 1 is transferred to the compression unit 306, and the compressed data is transferred. Stored in the compression band 1 of the memory 310. At this time, as shown in the compressor input data within the dotted line in the center of FIG. 10, in order to simultaneously perform the skew correction process, the mirror inversion process, and the upside down process, the data in the input buffer 1 are numbered L1, L2, L3, Data is read in the direction of the arrow in the order of L4 and L5 and compressed.

  Further, while the input raster data of the next band (input band 3) is being stored in the input buffer 3 of the memory 310, the previously stored data in the input buffer 1 and the input buffer 2 is transferred to the compression unit 306. The compressed data is stored in the compression band 2 of the memory 310. At this time, as indicated by the compressor input data in the dotted line in the center of FIG. 10, the data in the input buffer 1 and the input buffer 2 are assigned the number L1 in order to simultaneously perform the skew correction process, the mirror inversion process, and the upside down process. , L2, L3, L4, and L5 in the order of the arrows, data is read and compressed.

  The input raster data of the last band (input band 4) is stored again in the input buffer 1 of the memory 310, and the data stored in the input buffer 2 and the input buffer 3 in the meantime is transferred to the compression unit 306. The compressed data is stored in the compression band 3 of the memory 310. At this time, as indicated by the compressor input data within the dotted line in the center of FIG. 10, in order to perform skew correction, mirror inversion, and top-to-bottom inversion simultaneously, the directions of the arrows in the order of numbers L1, L2, L3, L4, and L5 The data is read out and compressed.

  Finally, the previously stored input buffer 3 and the data in the input buffer 1 are transferred to the compression unit 306, and the compressed data is stored in the compression band 4 of the memory 310. At this time, as shown in the compressor input data in the dotted line in the center of FIG. 10, in order to perform the skew correction process, the mirror inversion process, and the upside down process at the same time, the numbers L1, L2, L3, L4, L5, L6, Data is read in the direction of the arrow in the order of L7 and compressed.

  After compressing one page of input raster data by such a procedure, a printing operation is performed while decompressing the data through the decompression unit 307 in this order in the compression bands 4, 3, 2, 1 of the memory 310. As shown in the decompressor output data surrounded by the dotted line on the right side of FIG. 10, the decompressed data is illustrated as data that has been subjected to skew correction processing, mirror inversion processing, and upside down processing.

  When skew correction processing, mirror inversion processing, and upside down processing are simultaneously performed while performing band division in this way, the input buffer size for temporarily storing input raster data in the memory 310 is required for at least three bands. In FIG. 10, since the number of divided bands of the input raster data is set to 4 for convenience of explanation, the size of the input buffer requires 3/4 of one page, but actually a little more bands (for example, 10 to 20 bands). ), The buffer size can be reduced. However, if the number of band divisions is increased too much, the buffer size will be reduced, but managing the connection of the band-divided data will be complicated, and the processing speed will not be in time if the control of band connection is left to the software. Since there is a risk of harmful effects, an appropriate number of divisions is desirable.

(Embodiment 3)
In the first and second embodiments described above, the amount of skew correction (hereinafter referred to as “skew amount”) has been described as being known.

  In the third embodiment, an example of a configuration for detecting the skew amount will be described in detail.

  FIG. 11 is a schematic configuration diagram of an image forming apparatus according to Embodiment 3 of the present invention.

  FIG. 11 shows four photoconductors 601, 602, 603, and 604 and a transfer unit 605 extending over these as an example of the configuration of an image forming apparatus having a photoconductor as an image carrier. A so-called tandem type color image forming apparatus is shown. There are charging devices 606, 607, 608, 609, exposure devices 610, 611, 612, 613, developing devices 614, 615, 616, 617, and photoconductor cleaning devices around the respective photoconductors 601, 602, 603, 604. 618, 619, 620, 621 are arranged.

  Developer storage units 622, 623, 624, and 625 store toners of colors corresponding to the developing devices 614, 615, 616, and 617, respectively. The developing devices 614 to 617 are replenished so that the density becomes substantially constant.

  The transfer unit 605 includes a belt-like transfer body 626, a driving roller 627 for rotating and conveying the belt-like transfer body 626, a pressing roller 629 that applies a pressing force to the belt-like transfer body 626 via the recording paper 628, A support roller 630 located on the opposite side of the drive roller 627 across the recording paper 628 and a belt-like transfer member 601 in contact with the belt-like transfer member 601 by applying tension to the belt-like transfer member 626 at the time of image formation. It is composed of a tension roller 631 and the like for flattening the opposing surfaces.

  In Embodiment 3, the belt-like transfer body 626 constitutes a so-called intermediate transfer body that transfers the toner image directly on the surface thereof and then transfers it to the recording paper 628. Instead, for example, the belt-like transfer body 626 adsorbs the paper onto the belt. A so-called transfer paper transport body that transfers a toner image onto the paper may also be used.

  Note that the transfer unit 605 is provided with a belt cleaning device 632 for cleaning so-called residual toner remaining on the surface of the belt-shaped transfer body 626 without being transferred to the recording paper 628.

  In addition, the color image forming apparatus shown in FIG. 11 has a paper feed cassette 633 for storing the recording paper 628, and the recording paper 628 is transferred from the paper feed cassette 633 to the recording paper including the support roller 630 and the pressing roller 629. A sheet feeding unit 638 including a sheet feeding roller 635 for supplying to the unit 634, a pickup roller 636, a registration roller 637, a fixing device 639 for fixing the toner image transferred on the surface of the recording sheet 628, and the like are provided. It has been.

  FIG. 12 is a sectional view of an exposure apparatus mounted on the image forming apparatus according to Embodiment 3 of the present invention.

  Hereinafter, the configuration of the exposure apparatus according to the third embodiment will be described with reference to FIG.

  The color image forming apparatus according to the third embodiment includes exposure apparatuses 610 to 613 corresponding to a plurality of photoconductors 601 to 604, but all have the same configuration. A single photoconductor 601 and an exposure apparatus 610 for exposing the photoconductor 601 will be described.

  In Embodiment 3, an organic electroluminescence element (hereinafter referred to as an organic EL element) is employed as the light emitting element 540 that exposes the photoconductor 601. A light-emitting element array in which the light-emitting elements 540 formed of the organic EL elements are arranged at a pitch corresponding to, for example, 600 dpi (that is, 42.3 μm) is formed on a glass substrate 544, and the glass substrate 544 has a long length. It is held in the housing 541 (extends in the direction toward the back of the sheet of FIG. 12). The glass substrate 544 is fixed at a predetermined position of the exposure apparatus 610 by fixing through a screw insertion hole (not shown) via positioning pins (not shown) provided at both ends of the long housing 541.

  The light emitting element 540 is driven by a thin film transistor 551 (hereinafter referred to as a TFT, see FIG. 13) formed over the same glass substrate 544 as the light emitting element 540.

  The gradient index rod lens array 546 is configured by stacking gradient index rod lenses on the front surface of the light emitting element 540, and constitutes an imaging optical system.

  Reference numeral 548 denotes a cover provided on the housing 541. The housing 541 covers the periphery of the glass substrate 544, and the side facing the photoconductor 601 is open.

  In such a structure, light emitted from the light emitting element 540 formed on the glass substrate 544 is imaged on the surface of the photoreceptor 601 by the rod lens array 546.

  A light-absorbing member (paint) (not shown) is provided on the surface of the housing 541 facing the end surface of the glass substrate 544.

  In Embodiment 3, the light emitted from the light emitting element 540 is configured to enter the rod lens array 546 through the glass substrate 544 (that is, the bottom emission structure), and thus the light emitting element 540 is formed. The substrate to be used needs to be made of a transparent material like the glass substrate 544, but the so-called top emission type that outputs light emitted from the light emitting element 540 without passing through the substrate on which the light emitting element 540 is formed. It is good. In this case, a ceramic substrate or the like may be used instead of the glass substrate 544. Note that the light emitting element array formed on the glass substrate 544 is sealed with a glass plate (not shown) or the like.

  FIG. 13 is a plan view showing the configuration of the organic EL light-emitting element array according to Embodiment 3 of the present invention.

  As shown in FIG. 13, the glass substrate 544 mounted on the exposure apparatus 610 of Embodiment 3 has light emitting elements 540_0001 to 540_5120 (that is, 5120) that are responsible for image formation arranged in the main scanning direction, and similarly. Light receiving sensors for detecting light from the outside of the exposure apparatus 610, provided corresponding to the light emitting elements for skew measurement 540a, 540b, 540c, and 540d provided on the glass substrate 544, and the light emitting elements for skew measurement 540a and 540b. A light receiving sensor 501b that detects light from outside the exposure apparatus 610 is formed corresponding to the light emitting elements 540c and 540d for skew measurement.

  The light emitting elements 540_0001 to 540_5120 responsible for image formation are controlled to be turned on / off according to the image data, whereby a so-called electrostatic latent image is formed on the photoreceptor 601 (see FIG. 12).

  In the following description, among the light emitting elements 540, the light emitting elements responsible for image formation are collectively described as the light emitting element 540pel. When the skew measuring light emitting elements are collectively described, they are described as a skew measuring light emitting element 540ad.

  Reference numeral 551 denotes a driver circuit that includes a TFT and supplies current to the light emitting element 540pel and the skew measuring light emitting element 540ad (hereinafter referred to as TFT 551).

  In FIG. 13, the interval between the skew measuring light emitting element 540 b and the light emitting element 540 — 0001 responsible for image formation is drawn close to each other for convenience, but actually, the skew measuring light emitting element 540 b is outside the image forming area of the photoconductor 601. (Same for all of the skew measuring light emitting elements 540ad).

  The skew measuring light emitting element 540ad is provided on the same surface of the light emitting element 540pel and the glass substrate 544 at a predetermined interval.

  The skew measuring light emitting element 540ad according to the third embodiment is generated at the same time as the light emitting element 540pel by distributing a polymer electroluminescent material, and constitutes a so-called organic EL element.

  Further, since the light receiving sensors 501a and 501b are also collectively generated by the same manufacturing process as the TFT 551, for example, a polysilicon forming process, the light receiving elements 540ad and the light receiving sensors 501a and 501b are added. There is an advantage that the function is improved without increasing the cost.

  Here, in Embodiment 3, the number of light emitting elements for skew measurement 540ad is four, but the number may be increased if the amount of light is insufficient, and the light emitting region (area) of the light emitting element for skew measurement 540ad is configured to be large. (In this case, the number may be reduced). In the third embodiment, the skew measuring light emitting element 540ad is provided separately from the light emitting element array formed by the light emitting element 540pel responsible for image formation. However, the number of light emitting elements constituting the light emitting element array is described above. The light emitting element provided near the light receiving sensors 501a and 501b may be used as the light emitting element for skew measurement. In this case, a part of the light emitting element 540pel is used as a light emitting element for skew measurement.

  In the third embodiment, the light receiving sensors 501a and 501b are provided at positions separated in the sub-scanning direction with respect to the light emitting element row formed by the light emitting elements 540pel that bears an image. The light emitting elements 540pel configure this. You may make it provide in the position shown on the substantially extended line of a light emitting element row | line, ie, Pos1 and Pos2. In this case, since the light receiving sensors 501a and 501b do not interfere with the arrangement position of the TFT 551, there is an advantage that the design of the TFT 551 becomes easy.

  FIG. 14 is a block configuration diagram showing the configuration of the skew amount detection unit in the third embodiment of the present invention.

  In FIG. 14, reference numeral 501 denotes a light receiving sensor for detecting the reflected light of the photoconductor 601 and corresponds to the light receiving sensors 501a and 501b described above (hereinafter referred to as the light receiving sensors 501a and 501b). Point to one). Reference numeral 502 denotes an A / D converter for quantizing the analog light quantity level of the light receiving sensor 501, and 503 denotes a control unit for recognizing the light quantity level quantized by the A / D converter 502 and performing arithmetic control.

  Reference numeral 506 denotes a drive circuit for causing the skew measurement light emitting element 540ad to emit light. In response to a lighting signal from the control unit 503, a supply current flows from the drive circuit 506 to the skew measurement light emitting element 540ad, and light emission is started. The light flux forms an image on the photosensitive member 601 through the above.

  Then, the light reflected by the surface of the photoconductor 601 enters the light receiving sensor 501 again via the rod lens array 546.

  FIG. 15 is an explanatory diagram of an imaging optical system centering on the rod lens array 546 in Embodiment 3 of the present invention.

  In FIG. 15, when the working distance, which is the distance from the end surface of the rod lens array 546 to the object or the image plane, is L0, and the length of the rod lens array 546 itself is Z0, the conjugate length Tc of the rod lens array 546 is Tc. = Z0 + 2 × L0.

  The light emitting element 540 (both the light emitting element 540pel responsible for image formation and the light emitting element for skew measurement 540ad) and the rod lens array 546 in the exposure apparatus 610 so that the light beam is completely imaged (focused) on the photoconductor 601. And the photosensitive member 601 are in a conjugate relationship as described above.

  With such a configuration, both the light emitted from the above-described light emitting element for skew measurement 540ad and the light emitting element 540pel responsible for image formation are imaged on the surface of the photoreceptor 601 by the rod lens array 546.

  FIG. 16 is a configuration diagram showing the configuration of the photoconductor 601 incorporated in the image forming apparatus according to Embodiment 3 of the present invention.

  As shown in FIG. 16, detection markers M <b> 1 and M <b> 2 are provided on the photoreceptor 601 outside the image forming area in the main scanning direction. The detection markers M1 and M2 are formed so as to have different reflection characteristics from the surface of the photoreceptor 601.

  The detection markers M1 and M2 are for measuring the absolute position in the rotation direction of the photosensitive member 601, and are not formed by the toner image when measuring the skew amount, but are fixed patterns.

  For example, when the surface of the photoconductor 601 exhibits a strong regular reflection characteristic, the detection markers M1 and M2 are formed to have a strong diffuse reflection characteristic by partially roughening the surface of the photoconductor 601. Alternatively, it is formed by distributing a paint having good absorption characteristics with respect to the wavelength of the light emitting element 540 formed of an organic EL element. Conversely, when the surface of the photoconductor 601 has diffuse reflection characteristics, the surface of the photoconductor 601 is partially mirror-polished so as to have strong regular reflection characteristics. Further, the positions of the detection markers M1 and M2 in the sub-scanning direction are formed so as to be at the same interval with respect to the reference line P0 parallel to the main scanning direction of the photosensitive member 601 (that is, Δp1 = Δp2). In the third embodiment, the photoconductors 602 to 604 have the same configuration.

  Based on the configuration of the image forming apparatus described above, the process of detecting the amount of skew when the exposure apparatus 610 is inclined with respect to the main scanning direction of the photoconductor 601 (hereinafter referred to as skew) will be described.

  17, FIG. 18, and FIG. 19 are explanatory diagrams for explaining a skew amount detection process in the third embodiment of the present invention.

  As shown in FIGS. 17 and 18, the optical positional relationship between the detection markers M1 and M2 on the photoconductor 601 and the skew measuring light emitting element 540ad and the light receiving sensors 501a and 501b provided in the exposure apparatus 610 is the skew. The emitted light output from the measurement light emitting elements 540a and 540b irradiates the detection marker M1, and the reflected light enters the light receiving sensor 501a. Also, the output light output from the skew measurement light emitting elements 540c and 540d. The optical arrangement is such that the incident light irradiates the detection marker M2 and the reflected light is incident on the light receiving sensor 501b (the detection markers M1 and M2 are mirror surfaces and have strong regular reflection). Configuration when showing characteristics).

  Alternatively, when the light emitted from the skew measuring light emitting element 540ad is irradiated on the surface of the photoconductor 601 other than the detection markers M1 and M2, the reflected light may be incident on the light receiving sensors 501a and 501b. (The above is the case where the surface of the photoconductor 601 forms a mirror surface and the skew detection markers M1 and M2 form a diffusion surface).

  As described above, exposure apparatus 610 of Embodiment 3 is an exposure apparatus that exposes an image carrier (photosensitive body 601) to form an image on the image carrier, and is a light emitting device that includes a plurality of light emitting elements. Provided corresponding to the element rows (light emitting elements 540a and 540b for skew measurement and the light emitting element 540pel responsible for image formation) and a part of the light emitting elements constituting the light emitting element row (light emitting element for skew measurement 540ad); And a light receiving unit (light receiving sensors 501a and 501b) for detecting light incident from the outside of the exposure apparatus (that is, light reflected from the photosensitive member 601 as an image carrier).

  In this configuration, if the light emitting element 540pel responsible for image formation is defined as a first light emitting element and the skew measuring light emitting element 540ad is defined as a second light emitting element, the exposure apparatus 610 of Embodiment 3 includes a plurality of first light emitting elements. A light emitting element array composed of light emitting elements, a second light emitting element provided outside the arrangement range of the light emitting element array (that is, outside the image forming area), and provided corresponding to the second light emitting element. In other words, the light receiving unit may detect light incident from the outside of the exposure apparatus.

  Next, the process of detecting the skew amount will be described with reference to FIGS.

  In the state shown in FIG. 18, the exposure device 610 is attached with a slight inclination with respect to the main scanning direction of the photosensitive member 601, and after the power of the image forming apparatus is turned on, the photosensitive member 601 is driven by an unillustrated driving means in FIG. It rotates in the direction of. At a predetermined time t0, the skew measuring light emitting element 540ad starts to emit light in response to a driving signal from the driving circuit 506 (see FIG. 19). If the surface of the photoconductor 601 exhibits strong specular reflection, the light receiving sensors 501a and 501b A high level of light is incident. When the detection markers M1 and M2 on the photoconductor 601 approach the vicinity of the exposure device 610, the emitted light beam from the skew measuring light emitting element 540ad irradiates the detection markers M1 and M2, and changes from regular reflection to diffuse reflection. . That is, when the detection markers M1 and M2 are detected, the amount of light incident on the light receiving sensors 501a and 501b decreases, and therefore the passing time of the leading or trailing end of the detecting markers M1 and M2 in the photosensitive member 601 rotation direction R0 is measured. can do.

  Accordingly, two timers (not shown) provided in the control unit 503 (see FIG. 14) start the timer from the light emission start time t0 as shown in FIG. 19, and the light amount level incident on the light receiving sensors 501a and 501b is reduced. Each time is monitored independently (that is, the count value of the timer increases as the detection timing of the detection markers M1 and M2 is delayed). The light emitting element 540ad for skew measurement and the light emitting element 540pel responsible for image formation are arranged in parallel to the main scanning direction of the exposure apparatus 610. Further, as described above, the front end portion or the rear end of the detection markers M1, M2 The exposure unit 610 is parallel to the main scanning direction of the photoconductor 601 when the above-described times are the same. However, if they are not simultaneously, they are skewed (inclined) with respect to the main scanning direction.

  It makes sense to use two timers as described above. If the timer is set to one system and the timer operation is started based on the detection timing of t2, for example, when the detection timings of t1 and t2 are reversed, the value of the timer count becomes large (worst case) The counting is continued for the time that the photoconductor 601 makes a round). This is nothing but a difference in detection time between the detection of two events, and there is a possibility that an extra error component due to uneven rotation cycle of the photosensitive member 601 may be mixed in the skew amount measurement.

  Now, the difference between t1 and t2 measured by two systems of timers, that is, the time difference Δt = t1−t2, has a sign (+ or −) indicating the skew direction, and an absolute value indicating the magnitude of the skew amount. In the third embodiment, the skew amount as the distance information is obtained by multiplying the time difference Δt by the driving speed of the photosensitive member 601 (process speed P shown in FIG. 19). The calculation of the skew amount is executed by the control unit 3 (see FIG. 14). Based on the skew amount thus measured, the skew correction processing described in detail in the first and second embodiments is performed.

  As described above, in the first to third embodiments, the color image forming apparatus has been described as an example to which the image processing apparatus or method of the present invention is applied. However, the present invention also applies to a monochrome image forming apparatus. Needless to say, this is applicable.

  The present invention can be used in printing operations such as copying a document, printing an image scanned by a scanner, printing an image taken by a digital camera, and a document created by application software of a host device. The present invention can be applied to applications such as a digital copying machine, a multifunction printer device, and a printer device.

Explanatory drawing which shows the connection with the multifunction apparatus of Embodiment 1 of this invention, and its external apparatus 1 is a schematic configuration diagram of a data processing unit of a multifunction device according to Embodiment 1 of the present invention. 1 is a configuration diagram of a printing unit of a multifunction device according to Embodiment 1 of the present invention. The block diagram which shows the structure of each functional block of the data processing part in Embodiment 1 of this invention Explanatory drawing explaining the process of the skew correction process performed by the data processing part in Embodiment 1 of this invention, and a mirror inversion process Explanatory drawing explaining the process of the skew correction process performed in the data processing part in Embodiment 1 of this invention, a top-and-bottom inversion process, and a mirror inversion process Explanatory drawing which shows the address which a compression address control part outputs in Embodiment 1 of this invention. The flowchart which shows operation | movement of a compression address control part in Embodiment 1 of this invention. Explanatory drawing explaining the process in which skew correction processing, top-and-bottom inversion processing, and mirror inversion processing are executed by the address output from the compressed address control unit in Embodiment 1 of the present invention Explanatory drawing explaining the process of the data processing of a data processing part in Embodiment 2 of this invention. Schematic configuration diagram of an image forming apparatus according to Embodiment 3 of the present invention. Sectional drawing of the exposure apparatus mounted in the image forming apparatus in Embodiment 3 of this invention The top view which shows the structure of the organic electroluminescent light emitting element array in Embodiment 3 of this invention. The block block diagram which shows the structure of the skew amount detection part in Embodiment 3 of this invention. Explanatory drawing of the imaging optical system centering on the rod lens in Embodiment 3 of this invention Configuration diagram showing a configuration of a photoconductor built in an image forming apparatus according to Embodiment 3 of the present invention. Explanatory drawing explaining the skew amount detection process in Embodiment 3 of this invention. Explanatory drawing explaining the skew amount detection process in Embodiment 3 of this invention. Explanatory drawing explaining the skew amount detection process in Embodiment 3 of this invention. Explanatory drawing showing the state of the print line when skew occurs on the printing paper and after skew correction Explanatory drawing which shows the state of the printing line at the time of skew occurrence in the color image forming apparatus and after skew correction Configuration diagram of an image processing device configured to be able to execute skew correction in combination with top and bottom inversion and mirror inversion using conventional technology

Explanation of symbols

1a to 1d Image forming station 2a to 2d Photoconductor 3a to 3d Charging means 4a to 4d Developing means 5a to 5d Cleaning means 6a to 6d Exposure means 8a to 8d Transfer means 9a to 9d Exposure light 12 Intermediate transfer belt 13 Raster data receiving section DESCRIPTION OF SYMBOLS 14 Pattern detection means 16 Paper feed cassette 17 Sheet material 18 Paper feed roller 19 Transfer roller 20 Fixing device 100 Memory 101 Copy / print image processing 101a Copy image processing 101b Print image processing 102 Interface 103 CPU
104 ROM
106 Mirror inversion unit 108 Upside down inversion unit 110 Skew correction unit 112 Data compression unit 114 Data decompression unit 115 Raster data storage area 116 Data storage area after mirror inversion processing 117 Data storage area after upside down processing 118 Data storage area after skew correction processing 119 Compressed data storage area 200 Multi-function device 201 Interface unit 202 Scanner unit 203 Control unit 204 Data processing unit 205 Printing unit 206 Personal computer (PC)
207 Digital Camera 208 FAX Line 301 Receiving Unit 302 Copy Image Processing Unit 303 Print Processing Unit 304 Digital Camera Image Processing Unit 305 FAX Processing Unit 306 Compression Unit 307 Decompression Unit 308 Data Transmission Unit 310 Memory 312 ROM
313 CPU (DSP)
314 Compression address control unit 315 Mirror inversion address control unit 316 Skew correction address control unit 317 Upside down address control unit 318 Decompression address control unit 320 Raster data storage area 321 Compressed data storage area 501, 501 a, 501 b Light receiving sensor 502 A / D converter 503 Control unit 504 Actuator drive unit 506 Drive circuit 540 Light emitting element 540 pel Light emitting element (light emitting element) responsible for image formation
540a, 540b, 540c, 540d, 540ad Light emitting element for skew measurement 544 Glass substrate 545 Light emitting part 546 Rod lens array 551 TFT (thin film transistor)
601 602 603 604 photoconductor 605 transfer unit 606 607 608 609 charging device 610 611 612 613 exposure device 614 615 616 617 developing device 618 619 620 621 photoconductor cleaning device 622, 623, 624, 625 Developer storage unit 626 Belt-shaped transfer body 627 Driving roller 628 Recording paper 629 Pressing roller 630 Support roller 631 Tension roller 632 Belt cleaning device 639 Fixing device M1, M2 Detection marker S Start address (address generation) Initial value of processing)
B Start address of raster data E Last address of raster data M Number of main scanning pixels N Total number of pixels p1 Distance to first skew correction point p2 Distance to second skew correction point i Main scanning counter j Sub scanning counter k Pixel counter r Address variable x Scanning direction of main scanning y Scanning direction of subscanning z Skew correction direction Ad Output address value

Claims (10)

Raster data storage memory for storing raster data of print images;
A read address control unit that generates a read address of the raster data stored in the raster data storage memory, at least according to the necessity of execution of skew correction processing and other processing;
According to the read address generated by the read address control unit, the raster data is read, and a compression unit that performs a predetermined compression process;
An image processing apparatus comprising: The image processing apparatus according to claim 1,
The other processing,
Mirror inversion processing for inverting the left and right of the printed image;
An image processing apparatus as at least one of the top and bottom inversion processing for top and bottom of the print image. Raster data storage memory for storing raster data of print images;
A read address control unit that generates a read address of the raster data stored in the raster data storage memory;
A compression unit that reads the raster data in accordance with a read address generated by the read address control unit and performs a predetermined compression process;
A compressed data storage memory for storing data compressed by the compression unit;
A decompression unit that reads the compressed data from the compressed data storage memory and performs decompression processing;
A data output unit that outputs the raster data expanded by the expansion unit to an image forming apparatus;
The read address control unit
A skew correction unit that generates a read address so as to correct the skew of the image forming apparatus;
A mirror inversion unit that generates a read address so as to invert the left and right of the print image;
A top-and-bottom inversion unit that generates a read address so that the top and bottom of the print image are top and bottom;
An image processing apparatus composed of Raster data storage memory that divides raster data of a print image into several areas in the sub-scanning direction of printing and stores each band;
A read address control unit that generates a read address of the raster data stored in the raster data storage memory;
A compression unit that reads the raster data in accordance with a read address generated by the read address control unit, and performs a predetermined compression process for each band;
A compressed data storage memory for storing the data compressed for each band by the compression unit;
A print order storage unit that stores information representing the print order of the compressed data for each band;
A decompression unit that reads out the compressed data from the compressed data storage memory for each band according to the print order recorded by the print order storage unit, and performs decompression processing;
A data output unit that outputs the raster data expanded by the expansion unit to an image forming apparatus;
The read address control unit
A skew correction unit that generates a read address so as to correct the skew of the image forming apparatus;
A mirror inversion unit that generates a read address so as to invert the left and right of the print image;
A top-and-bottom inversion unit that generates a read address so that the top and bottom of the print image are top and bottom;
An image processing apparatus composed of The image processing apparatus according to claim 3, wherein:
The raster data storage memory and the compressed data storage memory share the same memory. The image processing apparatus according to claim 3, wherein:
An image processing apparatus configured to operate the compression unit and the decompression unit simultaneously in parallel. An image processing apparatus according to any one of claims 1, 3, and 4,
An image processing apparatus using the raster data as binary image data. An image processing apparatus according to any one of claims 1, 3, and 4,
An image processing apparatus in which the raster data is multivalued image data. Save raster data of print image in memory,
At least according to the necessity of execution of skew correction processing and other processing, a read address of raster data stored in the memory is generated,
An image processing method for reading the raster data in accordance with the generated read address and performing a predetermined compression process. Save raster data of print image in memory,
Performs read address control of the memory, reads the raster data specified by the controlled address,
A predetermined compression process is performed on the read raster data,
The data compressed by this compression process is stored in the memory,
Read the compressed data from the memory and perform decompression processing,
In an image processing method for outputting raster data expanded by this expansion processing to an image forming apparatus,
Read address control when performing the predetermined compression processing is as follows:
In addition to read address control for correcting the skew of the image forming apparatus,
Read address control for inverting the left and right of the print image;
An image processing method for generating an address by combining at least one address control among the read address controls for top and bottom of the print image.

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