JP2007155766A - Image forming apparatus, image forming method and image forming program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of outputting an image of high image quality, free from misalignment related to each color, and to provide an image forming method and an image forming program. <P>SOLUTION: A transfer condition acquiring part 131 acquires a transfer condition related to image information from the image information. A subscanning correction value calculation part 133 specifies a subscanning delay amount correction value from a subscanning delay amount correction value storage part 134 that stores delay amount correction value information where the transfer condition showing the transfer information is correlated with the subscanning delay amount correction value showing the correction value in the subscanning direction for each color based on the transfer condition acquired by the transfer condition acquiring part 131. A subscanning signal output part 125 outputs a subscanning timing signal based on the subscanning delay amount correction value specified by the subscanning correction value calculating part 133, then, a toner image writing position on the transfer belt is controlled. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus, an image forming method, and an image forming program, and particularly to prevention of color misregistration in a color image.

  Conventionally, as a color image forming apparatus, a tandem type color image forming apparatus that superimposes each color on a transfer belt and transfers a color image onto a transfer medium is generally known. In such a color image forming apparatus, there has been a problem in that color misregistration occurs due to a shift in the position of each color image transferred to a transfer medium on a transfer belt, resulting in a reduction in image quality.

  As a solution to such a problem, a color image forming apparatus that aligns images of respective colors has been disclosed (see Patent Document 1). Such an image forming apparatus detects a correction pattern formed on the transfer belt, and if there is a deviation, corrects the position by performing correction of the writing timing in the main scanning direction and the writing timing in the sub scanning direction. This is to correct the deviation.

JP 2002-244387 A

  However, in the technique disclosed in Patent Document 1 in which the image processing that is actually performed when outputting image data is different from the image processing that is performed on the correction pattern at the time of detecting the correction pattern, the correction pattern detection is used. There is a problem in that the position shift of each color cannot be eliminated only by correcting the calculated correction value of the position shift.

  The present invention has been made in view of the above, and provides an image forming apparatus, an image forming method, and an image forming program capable of outputting a high-quality image in which misregistration of each color is prevented. Objective.

  In order to solve the above-described problems and achieve the object, the invention according to claim 1 acquires image information, forms a toner image of a plurality of colors corresponding to the image information, and transfers the toner image on a transfer belt. In an image forming apparatus that transfers images superimposed on a medium, a sub-scanning delay amount correction value indicating a transfer condition indicating information related to the transfer and a correction value for a positional deviation in the sub-scanning direction between colors generated when forming a toner image. In the sub-scanning delay amount correction value storage means, the transfer condition acquisition means for acquiring the transfer condition for the image information from the image information, and the sub-scanning delay amount correction value storage means in the transfer Sub-scanning correction value specifying means for specifying the sub-scanning delay amount correction value associated with the transfer condition acquired by the condition acquiring means; and the sub-scanning correction value specifying means Therefore, based on the sub-scanning delay amount correction value specified, characterized in that it comprises an image forming means for correcting the writing position of the toner image in the transfer belt.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the image forming unit performs image data based on the sub-scanning delay amount correction value specified by the sub-scanning correction value specifying unit. The toner image writing position on the transfer belt is corrected by controlling the transmission timing.

  According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the transfer position, which is a position on the transfer belt and is a position to transfer the toner image of each color, is corrected. Correction pattern detection means for acquiring detection information of the correction pattern transferred for the purpose, and positional deviation correction value calculation means for calculating a sub-scanning positional deviation correction value based on the detection information acquired by the correction pattern detection means The image forming means further corrects the writing position of the toner image on the transfer belt based on the sub-scanning position deviation correction value calculated by the position deviation correction value calculation means, It is characterized by.

  According to a fourth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, information indicating that the transfer condition is at least image data received by a printer controller, or One of the information indicating that the image data is read from the scanner is included.

  According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the transfer condition includes at least the number of gradations of the acquired image information. And

  According to a sixth aspect of the present invention, in the image forming apparatus according to any one of the first to fifth aspects, the transfer condition includes at least a resolution of the acquired image information. .

  According to a seventh aspect of the present invention, in the image forming apparatus according to any one of the first to sixth aspects, the transfer condition includes at least a resolution of image information to be formed by the image forming unit. It is characterized by.

  According to an eighth aspect of the present invention, in the image forming apparatus according to any one of the first to seventh aspects, the sub-scanning delay amount correction value is a value based on a predetermined transfer condition. It is characterized by this.

  The invention according to claim 9 is an image forming method in which image information is acquired, a toner image of a plurality of colors corresponding to the image information is formed, and the toner image is transferred onto a transfer medium while being superimposed on a transfer belt. A transfer condition acquisition step for acquiring a transfer condition for the image information from the image information, a transfer condition indicating information related to the transfer, and a correction value for a positional deviation in the sub-scanning direction between the colors generated when the toner image is formed. In the sub scanning delay amount correction value storage means for storing the sub scanning delay amount correction value indicating the sub scanning delay amount correction value, the sub scanning delay amount correction value associated with the transfer condition acquired by the transfer condition acquisition step Based on the sub-scanning correction value specifying step specified by the sub-scanning correction value specifying step and the sub-scanning delay amount correction value specified by the sub-scanning correction value specifying step, And having and an image forming step of correcting the writing position of the toner image in the shooting belt.

  According to a tenth aspect of the present invention, a computer is caused to execute the image forming method according to the ninth aspect.

According to the present invention, the transfer condition for the image information is acquired from the image information, the transfer condition indicating the information related to the transfer, and the correction value for the positional deviation in the sub-scanning direction between the respective colors generated when the toner image is formed. In the sub-scanning delay amount correction value storage means for storing the sub-scanning delay amount correction value indicating the sub-scanning delay amount correction value, the sub-scanning delay amount correction value associated with the transfer condition is specified, and the sub-scanning delay amount correction value is specified. Based on this, by correcting the writing position of the toner image on the transfer belt, it is possible to correct the shift of the writing position of each color in the sub-scanning direction in consideration of the delay due to image processing. There is an effect that a quality image can be output.

  Exemplary embodiments of an image forming apparatus, an image forming method, and an image forming program according to the present invention are explained in detail below with reference to the accompanying drawings. The present invention is not limited to these embodiments.

  The present embodiment will be described with reference to the accompanying drawings. First, a configuration example of a multifunction machine to which the present invention is applied will be described. FIG. 1 is a block diagram illustrating a configuration of a multifunction machine according to the present embodiment.

  The multifunction peripheral 100 according to the present embodiment includes pattern detection sensors 15 and 16, an engine control unit 110, a printer controller 140, a scanner 150, and LD (laser diode) control units 160K, 160M, 160C, and 160Y. An image forming unit and an image output unit (not shown) are provided.

  The pattern detection sensors 15 and 16 are sensors for detecting the correction pattern transferred to the transfer belt in order to calculate the positional deviation of each color image. The printer controller 140 receives image data transmitted from another information terminal or the like via a network. The scanner 150 acquires image data by reading a document.

  The engine control unit 110 performs image processing on image data received by the printer controller 140 or image data acquired from the scanner 150, performs writing control, and transmits LD light emission data obtained by converting the image data.

  The LD control unit 160 causes the LD to emit light based on the LD light emission data transmitted by the engine control unit 110. When the LD emits light, a toner image is formed on the photosensitive drum. The formed toner image is transferred to a transfer medium and output.

  The engine control unit 110 further includes a correction pattern detection unit 111, a CPU 112, a RAM 113, an image processing unit 114, and a writing control unit 115.

  The correction pattern detection unit 111 acquires detection information of the correction pattern transferred to the transfer belt in order to correct the positional deviation of each color image.

  Here, acquisition of detection information of the correction pattern formed on the transfer belt 3 will be described. FIG. 2 is an explanatory diagram showing a correction pattern formed on the transfer belt. In the multifunction peripheral 100 which is a tandem type color image forming apparatus, an alignment technique between colors is an important issue due to its configuration. Therefore, the multifunction peripheral 100 according to the present embodiment corrects the misregistration of each color prior to performing the actual color image forming operation on the transfer paper.

  Specifically, two detection sensors 15 and 16 are arranged at both ends of the transfer belt 3 in the main scanning direction, and the correction pattern 14 is arranged on the transfer belt 3 in correspondence with the arrangement positions of the detection sensors 15 and 16. Form. The formed correction pattern 14 is detected when the transfer belt 3 moves and sequentially passes through the detection sensors 15 and 16. The correction pattern detection unit 111 acquires signals detected by the correction pattern detection sensors 15 and 16.

The CPU 112 reads and executes programs and data stored in the RAM 113 and a ROM (not shown). Further, the CPU 112 transmits a start signal (STTRIG_N) serving as a reference for the transmission timing of the image data to the writing control unit 115.

  The image processing unit 114 performs various image processing on the image data received by the printer controller 140 and the image data acquired by the scanner 150.

  Next, details of the write control unit 115 will be described. The write control unit 115 further includes a signal output timing correction unit 117, a write control unit (K) 116K for each color, a write control unit (M) 116M, a write control unit (C) 116C, and a write control unit (Y) 116Y. ing.

  The signal output timing correction unit 117 calculates the sub-scanning delay amount from the positional deviation correction value and the delay amount correction value. Here, the misregistration correction value is a correction for correcting the output timing of the image data from the image processing unit 114 in order to correct the misregistration between the respective colors caused by the misalignment of the writing timing of the image data by the LD. Value. Further, the delay amount correction value corrects the output timing of the image data from the image processing unit 114 in order to correct the positional deviation between the colors caused by the delay in the writing image processing performed on the image data of each color. It is a correction value.

  FIG. 3 is a block diagram illustrating a detailed configuration of the signal output timing correction unit. The signal output timing correction unit 117 further includes a transfer condition acquisition unit 131, a misregistration correction value calculation unit 132, a sub scanning delay amount calculation unit 133, and a sub scanning delay amount correction value storage unit 134.

  The sub scanning delay amount correction value storage unit 134 defines a sub scanning delay amount correction value corresponding to the transfer condition. FIG. 4 is an explanatory diagram showing an example of the data configuration of the sub-scanning delay amount correction value storage unit. The sub scanning delay amount correction value storage unit 134 stores the transfer condition and the sub scanning delay amount correction value in association with each other. Note that the sub-scanning delay amount correction value storage unit 134 shown in FIG. 4 defines the sub-scanning delay amount correction value when the write image processing is not performed in the correction pattern detection processing.

  Here, the transfer condition indicates information relating to transfer, and is a correction value for correcting a positional deviation between the colors caused by a delay in the writing image processing performed on the image data of each color. This is a condition for determining a scanning delay amount correction value. The transfer conditions include the type of image data, the resolution of the input image, the number of gradations of the input image, and the resolution of the output image. Here, the printer of the image data type indicates image data transmitted via a network, and the copy indicates image data acquired by a scanner.

  The sub-scanning delay amount correction value is set for each color of black (K), magenta (M), cyan (C), and yellow (Y). Even under the same transfer conditions, the required image processing function may differ depending on the color. That is, the number of internal delay lines varies depending on the image processing of each color. The sub-scanning delay amount correction value is a value corresponding to such a delay.

Here, the sub-scanning delay amount correction value will be specifically described. For example, a monochrome image is subjected to smoothing processing, but a color image is not subjected to smoothing processing. When performing the smoothing process, it is necessary to refer to a plurality of lines, so a line memory for a plurality of lines is required. However, for colors that are not subjected to smoothing processing, it is sufficient to have a line memory for two lines at a maximum for speed conversion. Therefore, between K and color (M, C, Y), the number of internal delay lines in the writing control unit 122 necessary for outputting LD image data is different. The sub-scanning delay amount correction value is a value for correcting this delay.

  The transfer condition acquisition unit 131 acquires a transfer condition, which is a condition necessary for specifying a sub-scanning delay amount correction value, from image data or preset image data reading conditions and output conditions.

  The misregistration correction value calculation unit 132 determines various color misregistration amount correction values, specifically a main scanning magnification correction value, a main scanning position misalignment correction value, from the detection information of the correction pattern detected by the correction pattern detection unit 111. The sub-scanning position deviation correction value is calculated.

  The sub-scanning delay amount calculation unit 133 specifies a sub-scanning delay amount correction value from the sub-scanning delay amount correction value storage unit 134 according to the transfer condition acquired by the transfer condition acquisition unit 131. The sub-scanning delay amount is calculated by adding the sub-scanning position shift correction value calculated by the positional shift correction value calculation unit 132 to the sub-scanning delay amount correction value. Thereby, the sub-scan delay amount of each color is calculated.

  Next, the write control units 116K, 116M, 116C, and 116Y will be described. FIG. 5 is a block diagram showing a detailed configuration of the write control unit. Each color write control unit 116K, 116M, 116C, 116Y includes a line memory 121, a write image processing unit 122, a correction pattern generation unit 123, an LD data output unit 124, and a sub-scanning signal output unit 125 for each color. It has.

  The sub-scanning signal output unit 125 outputs the sub-scanning timing signal (* _FSYNC_N) according to the sub-scanning delay amount calculated by the sub-scanning delay amount calculation unit 133 of the signal output timing correction unit 117 with the start signal (STTRIG_N) as a reference. This is output to the image processing unit 114. The sub-scan signal output unit 125 for each color outputs a sub-scan timing signal for each color in accordance with the sub-scan delay amount for each color, so that the delay generated in the writing image processing unit 122 is absorbed, and the color image is misaligned. Color shift can be prevented.

  The line memory 121 is a memory that sequentially stores the image data sent from the image processing unit 114. The writing image processing unit 122 performs various types of image processing using image data stored in the line memory 121. For example, smoothing processing or edge processing is performed.

  The correction pattern generation unit 123 generates image data of the correction pattern 14 to be transferred to the transfer belt 3 in order to calculate a correction value for correcting the positional deviation of each color on the transfer belt 3 described above. .

  The LD data output unit 124 outputs LD data in order to transfer the image data processed by the writing image processing unit 122 to the photoconductor.

  Next, an image forming process performed by the MFP 100 configured as described above will be described. FIG. 6 is a flowchart illustrating an image forming process procedure performed by the correction pattern generation unit, the correction pattern detection unit, the transfer condition acquisition unit, the correction value calculation unit, the sub-scanning delay amount calculation unit, and the writing control unit.

The correction pattern generation unit 123 generates the correction pattern 14 (step S601). The image data of the correction pattern 14 for each of the K, M, C, and Y colors is transferred to the transfer belt 3 via the LD data output unit 124 and the LD control unit 160 for each color, and the correction pattern 14 is formed. The correction pattern detection unit 111 acquires detection information of the correction pattern 14 detected by the correction pattern detection sensors 15 and 16 (step S602).

  The misregistration correction value calculation unit 132 calculates a main scanning magnification correction value from the detection information detected by the correction pattern detection unit 111 (step S603). The misregistration correction value calculation unit 132 calculates a main scanning misregistration correction value from the detection information detected by the correction pattern detection unit 111 (step S604).

  A sub-scanning position deviation correction value is calculated from detection information detected by the correction pattern detection unit 111 (step S605). M, C, and Y sub-scanning position shift correction values are calculated with K as a reference. The M, C, and Y sub-scanning position shift correction values for K are A1, A2, and A3. As described above, it is possible to detect a displacement due to the timing at which the correction pattern is detected by the sensor, and to write it onto the transfer belt, and to calculate a correction value for correcting the displacement and control the writing timing. Therefore, it is possible to prevent a positional shift due to the writing timing and to output a high-quality image.

  The transfer condition acquisition unit 131 acquires a transfer condition for determining a sub-scanning delay amount correction value from information such as image data, an output condition, and an input condition (step S606). The sub-scanning delay amount calculation unit 133 determines the sub-scanning delay amount correction value for each color associated with the transfer condition acquired by the transfer condition acquisition unit 131 from the sub-operation delay amount correction value storage unit 134 (step S607). ). As described above, since the delay amount correction value can be set in advance from the transfer condition that can be determined by the input image data or the like, it is possible to prevent the positional deviation caused by the delay caused by the image processing. High-quality images can be output.

  The sub-scanning delay amount calculation unit 133 calculates the sub-scanning delay amount of each color by adding the sub-scanning position shift correction value and the sub-scan delay amount correction value for each color with reference to the value at the time of K misregistration correction. (Step S608). Specifically, the sub-scanning delay amount (* _mfcntld) based on the start signal includes the sub-scanning delay amount correction value (B0 to B3) and the sub-scanning position shift correction value (A1 to A3) when the color shift correction is executed. ) Can be obtained as follows.

K_mfcntld = value at the time of misalignment correction + B0
M_mfcntld = Value at the time of misalignment correction + A1 + B1
C_mfcntld = Value at the time of misalignment correction + A2 + B2
Y_mfcntld = Value at the time of misalignment correction + A3 + B3

  The output timing of the image data transmitted from the image processing unit 114 is controlled by the sub-scanning delay amount calculated by the sub-scanning delay amount calculating unit 133, and the printing process is performed (step S609). Specifically, a process for correcting sub-scanning color misregistration will be described. The alignment for correcting the color misregistration is based on the start signal and the image processing is performed on the sub-scan timing signal (* _FSYNC_N) reflecting the sub-scan delay amounts Y_mfcntld, M_mfcntld, C_mfcntld, and K_mfcntld calculated as described above. Output to the unit 114. The image processing unit 114 outputs a sub-scanning gate signal (* _IPFGATE_N) using * _FSYNC_N as a trigger, and the image data (* _IPDATA [7: 0] _N) is transferred. That is, the image data is output at a timing that takes into account the delay caused by the written image processing. After writing image processing on the image data, a toner image is formed on the photoconductor via the LD controllers 160K, 160M, 160C, and 160Y, and the image is output to a transfer medium. As a result, it is possible to prevent color misregistration due to image misregistration of each color.

FIG. 7 is a timing chart in which the sub-scanning delay amount calculated by the sub-scanning delay amount calculating unit is added. In FIG. 7, the sub-scanning delay amounts Y_mfcntld, M_mfcntld, C_mfcntld, and K_mfcntld of each color calculated by the sub-scanning delay amount calculation unit are reflected, and the sub-scanning gate signal (* _IPFGATE_N) is output. That is, image data (* _IPDATA [7: 0] _N) at the same timing
Is output. The LD data output unit 124 generates LD light emission data (* _LDDATA) from the image data delayed by the writing image processing, and outputs it to the LD control units 160K, 160M, 160C, and 160Y for each color. The LD control unit 160 causes the LD to emit light based on the LD emission data, forms a toner image on the photosensitive drum, and transfers and outputs the toner image to a transfer medium. Thus, by outputting the image data reflecting the sub-scan delay amount of each color, it is possible to prevent color misregistration between the colors.

  In the above description, the correction process used for the sub-scanning delay amount has been described. However, the correction process for the main scanning magnification correction value and the main scanning position deviation correction value is also performed by a known method, and the printing process is performed. .

  When correcting the misregistration between the colors, when correcting the misregistration by outputting a correction pattern, the correction pattern generation unit 123 generates and outputs the correction pattern without using the line memory 121. Therefore, the LD image data (* _LDDATA) is not delayed with respect to the sub-scanning gate signal (* _IPFGATE_N) output from the image processing unit 114.

  However, when outputting image data or the like actually read by the scanner 150, the line memory 121 is used, so that LD image data is output for the sub-scanning gate signal (* _IPFGATE_N) output from the image processing unit 114. (* _LDDATA) may be delayed. In addition, the number of lines used may differ for each color. In the present application, it is possible to correct color misregistration due to misregistration between colors due to the use of the line memory 121 and the difference in the number of used lines.

  Next, specific delay amount correction will be described. FIG. 8 is a timing chart for explaining an example of correction of the sub-scanning delay amount. In this example, C and Y are omitted because they have the same timing as M, and timing charts for K and M are shown.

  When the correction pattern is output, since the line memory 121 is not used as described above, the LD image data (* _LDDATA) is not delayed with respect to the sub-scanning counter, that is, the sub-scanning gate signal (* _IPFGATE_N).

  In the case of image data type: printer, resolution of input image: 600 dpi, number of gradations of input image: binary, output image analysis level: 600 dpi output (without correction), 4 lines are provided by writing image processing unit (K) 122K. The write image processing unit (M) 122M is delayed by one line. In this case, the absolute position of sub-scanning is shifted by 4 lines for K and 1 line for M compared to when the correction pattern is output. That is, even if the position deviation correction value is calculated using the correction pattern, the position deviation occurs unless correction is made taking this difference into account.

  The case of image data type: printer, resolution of input image: 600 dpi, number of gradations of input image: binary, analysis degree of output image: 600 dpi output (with correction) will be described. In the MFP 100 according to the present embodiment, the sub-scanning delay amount correction value for correcting the difference in delay amount in the writing control unit 115 when the correction pattern and the actual image are printed is used as the sub-scanning delay in FIG. Refer to the amount correction value storage unit 134. As the sub-scanning delay amount correction value, K = −4 and M = −1 are specified. The delay amount is corrected by reflecting the sub-scan delay amount correction values K = −4 and M = −1 in the start signal reference sub-scan delay amount (* _mfcntld). Therefore, the multifunction peripheral 100 according to the present embodiment can output a high-quality image with color misregistration prevented.

An example of correcting color misregistration in another sub-scanning direction will be described. FIG. 9 is a timing chart for explaining an example of correction of the sub-scanning delay amount when color misregistration occurs due to a certain transfer condition. Image data type: copy, input image resolution: 600 dpi, number of input image gradations: multilevel (4 bits), output image resolution: 600 dpi output, write in K and color (M, C, Y) In this example, the number of delay lines in the image processing unit 122 is the same number of one line. As the correction values obtained from the sub-scan delay amount correction value (B) in FIG. 4, K = −1, M = −1, C = −1, Y = −1, and the start signal reference sub-scan delay amount (* _mfcntld ), The delay amount is corrected.

  Further, in the case of image data type: printer, resolution of input image: 300 dpi, number of gradations of input image: binary, output image resolution: 600 dpi output, K = −8, M as the sub-scanning delay amount correction value The delay amount is corrected by reflecting = −2, C = −2, Y = −2 in the sub-scan delay amount (* _mfcntld) based on the start signal. Note that the writing control unit 122 performs sub-scanning double-dense processing.

  An example of correcting misalignment in another sub-scanning direction will be described. FIG. 10 is a timing chart for explaining an example of correction of the sub-scanning delay amount when color misregistration occurs due to a certain transfer condition. This is an example when the resolution of the printer is doubled and the line period is halved. Image data type: printer, resolution of input image: 1200 dpi, number of gradations of input image: binary, resolution of output image: 600 dpi, as a correction value obtained from the sub-scanning delay amount correction value (B) in FIG. The delay amount is corrected by reflecting K = −8, M = −2, C = −2, and Y = −2 in the sub-scan delay amount (* _mfcntld) based on the start signal.

  As another example, a description will be given of correction of a delay amount when a misregistration correction pattern is generated and set to the same delay amount as the sub-scanning internal delay amount in the writing control unit under a certain transfer condition. FIG. 11 is a timing chart for explaining an example of correction of the sub-scanning delay amount when color misregistration occurs due to a certain transfer condition. In this case, the reference of the sub-scanning position is based on the image data type: printer, the resolution of the input image: 600 dpi, the number of gradations of the input image: binary, and the resolution of the output image: 600 dpi.

  FIG. 12 is an explanatory diagram illustrating an example of a data configuration of the sub-scanning delay amount correction value storage unit. The difference from the above-described sub-scanning delay amount correction value storage unit 134 is that the sub-scanning delay amount correction value is defined when the write image processing is performed under a predetermined transfer condition in the correction pattern detection processing. Specifically, the predetermined transfer conditions are: image data type: printer, resolution of input image: 600 dpi, number of gradations of input image: binary, resolution of output image: 600 dpi. As a reference, a sub-scanning delay amount correction value under other transfer conditions is defined.

  In such a case, the correction values obtained from the sub-scanning delay amount correction value (B) in FIG. 12 are K = + 3, M, C, and Y = 0. By reflecting the correction value on the sub-scan delay amount (* _mfcntld) based on the start signal, the delay amount is corrected. In other words, the LD image has the same timing as the reference transfer conditions (in this case, image data type: printer, resolution of input image: 1200 dpi, number of gradations of input image: binary, resolution of output image: 600 dpi). If correction is made so that data (* _LDDATA) is output, misalignment correction due to writing timing by LD is dealt with separately, and misalignment due to writing image processing can be corrected. Even in other modes, an image in which color misregistration is prevented can be printed by using the values shown in FIG.

  In this way, by generating and using a correction value table based on the correction values when the misregistration correction pattern is formed under the same conditions as the transfer conditions used when forming the image data, it is possible to The value to be added as the scanning delay amount correction value is reduced, the adjustment time is shortened, and the processing time can be reduced.

Here, the image forming principle of the color image forming apparatus which is the premise of the present embodiment will be described. FIG.
FIG. 3 is an explanatory diagram illustrating a configuration of an image processing unit and a transfer belt of a multifunction peripheral that is a color image forming apparatus.

  Image processing units 1Y, 1M, 1C, and 1K that form images of the respective colors are arranged in a line along a transfer belt 3 that conveys a transfer sheet 2 as a transfer medium. The transfer belt 3 is installed between a driving roller 4 that rotates and a driven roller 5 that rotates and is driven to rotate in the arrow direction A → A ′ by the rotation of the driving roller 4. A paper feed tray 6 in which the transfer paper 2 is stored is provided below the transfer belt 3. The transfer sheet 2 at the uppermost position among the transfer sheets 2 stored in the sheet feed tray 6 is fed toward the transfer belt 3 during image formation, and is attracted onto the transfer belt 3 by electrostatic adsorption. The adsorbed transfer paper 2 is conveyed to the first image processing unit 1Y, where yellow image formation is performed.

  The first image processing unit 1Y includes a photosensitive drum 7Y, and a charger 8Y, an exposure unit 9, a developing unit 10Y, and a photosensitive cleaner 11Y disposed around the photosensitive drum 7Y. The surface of the photosensitive drum 7Y is uniformly charged by the charger 8Y, and then exposed by the exposure device 9 with the laser light LY corresponding to the yellow image, thereby forming an electrostatic latent image. The formed electrostatic latent image is developed by the developing device 10Y, and a toner image is formed on the photosensitive drum 7Y. This toner image is transferred to the transfer paper 2 by the transfer device 12Y at a position (transfer position) where the photosensitive drum 7Y and the transfer paper 2 on the transfer belt 3 are in contact with each other. ) Is formed. In the photoreceptor drum 7Y after the transfer, unnecessary toner remaining on the drum surface is cleaned by the photoreceptor cleaner 11Y to prepare for the next image formation.

  As described above, the transfer paper 2 on which the single color (yellow) is transferred by the first image processing unit 1Y is conveyed to the second image processing unit 1M by the transfer belt 3. Similarly, the toner image (magenta) formed on the photosensitive drum 7M is transferred onto the transfer paper 2 in a similar manner. The transfer paper 2 is further conveyed to the third image processing unit 1C and the fourth image processing unit 1K in order, and similarly, the formed toner image is transferred to the transfer paper 2 and thereby on the transfer paper 2 A color image is formed. The second to fourth image processing units 1M, 1C, and 1K have the same structure as that of the first image processing unit 1Y, and thus description thereof is omitted.

  Further, the transfer paper 2 on which the color image has been formed by passing through the fourth image processing unit 1 is peeled off from the transfer belt 3, fixed by the fixing device 13, and then discharged.

  FIG. 14 is a block diagram illustrating a hardware configuration of the multifunction machine according to the present embodiment. As shown in the figure, the multifunction peripheral 100 has a configuration in which a controller 210 and an engine unit (Engine) 60 are connected by a PCI (Peripheral Component Interconnect) bus. The controller 210 is a controller that controls the entire MFP 100 and controls drawing, communication, and input from an operation unit (not shown). The engine unit 60 is a printer engine that can be connected to a PCI bus, and is, for example, a monochrome plotter, a one-drum color plotter, a four-drum color plotter, a scanner, or a fax unit. The engine unit 60 includes an image processing part such as error diffusion and gamma conversion in addition to a so-called engine part such as a plotter.

The controller 210 includes a CPU 112, a north bridge (NB) 213, a system memory (MEM-P) 212, a south bridge (SB) 214, a local memory (MEM-C) 17, and an ASIC (Application Specific Integrated Circuit). 216 and a hard disk drive (HDD) 18, and the north bridge (NB) 13 and the ASIC 216 are connected by an AGP (Accelerated Graphics Port) bus 215. The MEM-P 212 includes a ROM (Read Only Memory) 212a and a RAM (Rando
m Access Memory) 113.

  The CPU 112 performs overall control of the multifunction peripheral 100, has a chip set including the NB 213, the MEM-P 212, and the SB 214, and is connected to other devices via the chip set.

  The NB 213 is a bridge for connecting the CPU 112 to the MEM-P 212, SB 214, and AGP 215, and includes a memory controller that controls reading and writing with respect to the MEM-P 12, a PCI master, and an AGP target.

  The MEM-P 212 is a system memory used as a memory for storing programs and data, a memory for developing programs and data, a drawing memory for printers, and the like, and includes a ROM 212 a and a RAM 113. The ROM 212a is a read-only memory used as a program / data storage memory, and the RAM 113 is a writable / readable memory used as a program / data development memory, a printer drawing memory, or the like.

  The SB 214 is a bridge for connecting the NB 213 to a PCI device and peripheral devices. The SB 214 is connected to the NB 213 via a PCI bus, and a network interface (I / F) unit and the like are also connected to the PCI bus.

  The ASIC 216 is an integrated circuit (IC) for image processing having hardware elements for image processing, and has a role of a bridge for connecting the AGP 215, the PCI bus, the HDD 18 and the MEM-C 17 respectively. The ASIC 216 includes a PCI target and an AGP master, an arbiter (ARB) that is the core of the ASIC 216, a memory controller that controls the MEM-C 17, and a plurality of DMACs (Direct Memory) that perform image data rotation by hardware logic and the like. Access Controller) and a PCI unit that performs data transfer between the engine unit 60 via the PCI bus. An FCU (Fax Control Unit) 30, a USB (Universal Serial Bus) 40, and an IEEE 1394 (the Institute of Electrical and Electronics Engineers 1394) interface 50 are connected to the ASIC 216 via a PCI bus.

  The MEM-C 17 is a local memory used as an image buffer for copying and a code buffer, and an HDD (Hard Disk Drive) 18 is a storage for storing image data, programs, font data, and forms. It is.

  The AGP 215 is a bus interface for a graphics accelerator card that has been proposed to speed up graphics processing. The AGP 215 speeds up the graphics accelerator card by directly accessing the MEM-P 212 with high throughput. .

  Note that the image forming program executed by the multifunction peripheral 100 of the present embodiment is provided by being incorporated in advance in a ROM or the like.

  The image forming program executed by the MFP 100 according to the present embodiment is a file in an installable or executable format, such as a CD-ROM, a flexible disk (FD), a CD-R, a DVD (Digital Versatile Disk), or the like. You may comprise so that it may record and provide on a computer-readable recording medium.

Further, the image forming program executed by the multifunction peripheral 100 of the present embodiment may be provided by being stored on a computer connected to a network such as the Internet and downloaded via the network. Further, the image forming program executed by the multifunction peripheral 100 of the present embodiment may be provided or distributed via a network such as the Internet.

  The image forming program executed by the MFP 100 according to the present embodiment includes a module configuration including the above-described units (transfer condition acquisition unit, correction value calculation unit, sub-scanning delay amount calculation unit, LD output timing control unit, and the like). As actual hardware, a CPU (processor) reads out and executes an image forming program from the ROM, and the respective units are loaded onto the main storage device, and a transfer condition acquisition unit, a correction value calculation unit, A scanning delay amount calculation unit, an LD output timing control unit, and the like are generated on the main storage device.

  Furthermore, in another modified example, the signal output timing correction unit 117 may not include the position deviation correction value calculation unit 132. In this case, only the delay caused by the writing image processing is corrected without performing the positional deviation correction.

1 is a block diagram illustrating a configuration of a multifunction machine according to an embodiment. It is explanatory drawing which shows the correction pattern formed on the transfer belt. It is explanatory drawing which shows the detailed structure of a signal output timing correction | amendment part. It is explanatory drawing which shows an example of a data structure of a subscanning delay amount correction value memory | storage part. It is a block diagram which shows the detailed structure of a write-control part. 5 is a flowchart illustrating an image forming process procedure performed by a correction pattern generation unit, a correction pattern detection unit, a transfer condition acquisition unit, a correction value calculation unit, a sub-scanning delay fishing correction unit, and an LD output timing control unit. 6 is a timing chart in which a sub-scanning delay amount calculated by a sub-scanning delay amount calculation unit is added. It is a timing chart for demonstrating an example of correction | amendment of subscanning delay amount. 6 is a timing chart for explaining an example of correction of a sub-scanning delay amount when color misregistration occurs due to certain transfer conditions. 6 is a timing chart for explaining an example of correction of a sub-scanning delay amount when color misregistration occurs due to certain transfer conditions. 6 is a timing chart for explaining an example of correction of a sub-scanning delay amount when color misregistration occurs due to certain transfer conditions. It is explanatory drawing which shows an example of a data structure of a subscanning delay amount correction value memory | storage part. FIG. 3 is an explanatory diagram illustrating a configuration of an image processing unit and a transfer belt of a multifunction peripheral that is a color image forming apparatus. It is a block diagram which shows the hardware constitutions of the multifunctional device concerning this Embodiment.

Explanation of symbols

15, 16 Correction pattern detection sensor 100 MFP 110 Engine control unit 111 Correction pattern detection unit 112 CPU
113 RAM
114 Image processing unit 115 Write control unit 116K Write control unit (K)
116M Write controller (M)
116C Write controller (C)
116Y Write control unit (Y)
117 Signal output timing correction unit 121 Line memory 122 Write image processing unit 123 Correction pattern generation unit 124 LD data output unit 125 Sub-scanning signal output unit 131 Transfer condition acquisition unit 132 Misalignment correction value calculation unit 133 Sub-scanning delay amount calculation unit 134 Sub-scanning delay amount correction value storage unit 140 Printer controller 150 Scanner 160K LD control unit (K)
160M LD controller (M)
160C LD controller (C)
160Y LD controller (Y)

Claims (10)

In an image forming apparatus that acquires image information, forms a toner image of a plurality of colors corresponding to the image information, and transfers the toner image on a transfer medium while being superimposed on a transfer medium.
Sub-scan delay amount correction that stores a transfer condition indicating information related to transfer and a sub-scan delay amount correction value that indicates a correction value for a positional deviation in the sub-scanning direction between the colors generated when the toner image is formed. Value storage means;
Transfer condition acquisition means for acquiring transfer conditions for the image information from the image information;
In the sub-scanning delay amount correction value storage unit, a sub-scanning correction value specifying unit that specifies the sub-scanning delay amount correction value associated with the transfer condition acquired by the transfer condition acquiring unit;
Image forming means for correcting the writing position of the toner image on the transfer belt based on the sub-scanning delay amount correction value specified by the sub-scanning correction value specifying means;
An image forming apparatus comprising:   The image forming unit corrects the writing position of the toner image on the transfer belt by controlling the transmission timing of the image data based on the sub-scanning delay amount correction value specified by the sub-scanning correction value specifying unit. The image forming apparatus according to claim 1, wherein: Correction pattern detection means for acquiring detection information of a correction pattern transferred in order to correct a transfer position, which is a position on the transfer belt, which is a position to transfer a toner image of each color;
A positional deviation correction value calculating means for calculating a sub-scanning positional deviation correction value based on the detection information acquired by the correction pattern detecting means;
The image forming means further corrects a toner image writing position on the transfer belt based on the sub-scanning position deviation correction value calculated by the position deviation correction value calculation means. The image forming apparatus according to claim 1.   The transfer condition includes at least either information indicating that the image data is received by a printer controller or information indicating that the image data is read from a scanner. The image forming apparatus according to any one of 3.   The image forming apparatus according to claim 1, wherein the transfer condition includes at least the number of gradations of the acquired image information.   The image forming apparatus according to claim 1, wherein the transfer condition includes at least a resolution of the acquired image information.   The image forming apparatus according to claim 1, wherein the transfer condition includes at least a resolution of image information to be formed by the image forming unit.   The image forming apparatus according to claim 1, wherein the sub-scanning delay amount correction value is a value based on a predetermined transfer condition. In an image forming method for acquiring image information, forming a toner image of a plurality of colors corresponding to the image information, and transferring the toner image on a transfer belt while being superimposed on a transfer medium.
A transfer condition obtaining step for obtaining a transfer condition for the image information from the image information;
Sub-scan delay amount correction that stores a transfer condition indicating information related to transfer and a sub-scan delay amount correction value that indicates a correction value for a positional deviation in the sub-scanning direction between the colors generated when the toner image is formed. In the value storage means, a sub-scanning correction value specifying step for specifying the sub-scanning delay amount correction value associated with the transfer condition acquired in the transfer condition acquiring step;
An image forming step of correcting a writing position of a toner image on the transfer belt based on the sub-scanning delay amount correction value specified in the sub-scanning correction value specifying step;
An image forming method comprising:   An image forming program for causing a computer to execute the image forming method according to claim 9.

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