JP4420453B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus that switches a recording signal addressed to a pixel in synchronization with a pixel synchronization clock that defines a pixel section on a line in the main scanning direction and performs pixel recording on the line in the main scanning direction by the recording signal. . One of the typical examples of this type of image forming apparatus is a laser printer, and the most typical one is that a plurality of image forming units that form toner images of different colors are arranged in tandem along a conveyance belt, This is a color laser printer in which toner images of different colors are superimposed and transferred onto a transfer belt and then transferred onto a sheet of paper, or overlaid onto a transfer sheet conveyed by a conveyance belt.

  An optical scanning device that forms a latent electrostatic image on a photoconductor by laser scanning the photoconductor of each image forming unit reflects the laser beam from the laser light source with a polygon mirror and reflects it with a first mirror through an fθ lens. The photosensitive member surface is exposed and scanned. However, in an image forming apparatus having a plurality of image forming units for forming each color image, misregistration (color shift) is likely to occur in image formation between the image forming units.

  Conventionally, with respect to such a positional deviation, the adjustment is called skew adjustment for changing the reflection angle of the first mirror, and the image writing start timing is controlled, so that it is orthogonal to the main scanning direction which is the laser scanning direction. The image position shift adjustment in the sub-scanning direction is performed, and the expansion and contraction of the image in the main scanning direction are adjusted by adjusting the frequency of the write CLK (pixel synchronization clock). Theoretically, as shown in FIGS. 19A and 19B, when the recording pixel (dotted line bar) is shifted in the main scanning direction with respect to the reference position (solid line bar), it is shown in FIGS. 19C and 19D. As shown, by changing the pixel synchronization clock from CLKo to CLKa, the deviation can be reduced as shown in (e). There is already a method for adjusting the misalignment in the main scanning direction by creating a misregistration detection mark on the belt, measuring the misalignment by reading it with a sensor, and adjusting the writing timing in the main scanning direction. Proposed. However, this adjustment method cannot correct a pixel position shift (pixel shift in the main scanning direction) caused by lens distortion or the like. For example, it was not possible to adjust for irregular changes caused by local distortion of the lens.

  The light beam emitted from the optical scanning device and scanned on the photosensitive member has a problem that the scanning speed on the photosensitive member varies depending on the ambient temperature. FIG. 20 is a graph showing changes in the amount of positional deviation in the main scanning direction due to temperature changes. As shown in the figure, the amount of positional deviation at each position of the lens changes with time as the temperature rises. This is because the oscillation wavelength of the laser fluctuates due to a change in the ambient temperature, and accordingly, the refractive index of the optical component such as a lens with respect to the incident laser light changes, and the thermal expansion of the component such as the casing of the optical scanning device. The main cause is that the position of an optical component such as a lens changes.

JP-A-6-320786 JP 2000-255098 A.

  In order to prevent image displacement and size variation due to fluctuations in the main scanning speed, Patent Document 1 discloses SOS (scanning start side end in the light beam scanning range) and EOS (scanning in the scanning range). It has been proposed to measure the scanning time of the laser beam between the end side ends) and to control the frequency of the clock signal by the PLL based on the measurement result. However, even in the above technique, no consideration is given to the correction of the partial magnification of the image (the positional deviation of each pixel in one main scanning line in the main scanning direction), and the variation in the partial magnification of the image (pixels in the main scanning direction). It is difficult to accurately correct image misalignment and size variation including misalignment).

  Patent Document 2 discloses a registration mark sensor arranged at three points on one line in the main scanning direction for the purpose of correcting the magnification (line length) and partial magnification (pixel shift on a line) of the entire image. The position of the mark in the main scanning direction is detected, the magnification of the entire image and the partial magnification of the image along the main scanning direction of the light beam are measured, and the deviation between the setting value of the magnification and the measured value is reduced, and The frequency average value of the pixel synchronization clock within one main scanning period of the light beam and the frequency of each ½ main scanning period are adjusted so that the deviation between the set value of the partial magnification and the measured value becomes small.

  However, registration marks are detected at three points, ie, both ends and the center point of one line in the main scanning direction, and the pixel synchronization clock frequencies of the first half and the latter half of one line are set based on these detection values, and at the beginning of each half area. Since the pixel synchronization clock frequency is set to the set value by the PLL, the main scanning position deviation of each pixel in each half region cannot be sufficiently corrected. For example, as shown in FIG. 22A, when the pixel position deviation is distributed in the main scanning direction, the pixel position deviation varies depending on the main scanning direction position in each of the first half and the second half of one line in the main scanning direction. In the frequency adjustment in the two sections of the first and second half, the adjustment of the pixel position deviation (partial magnification) in the main scanning direction is insufficient.

  The first object of the present invention is to adjust the pixel position deviation on one line in the main scanning direction at a higher density, and the second object is to automatically adjust the pixel position deviation due to a change in apparatus temperature. The third object is to perform these adjustments quickly.

(1) A recording signal addressed to a pixel is switched in synchronization with a pixel synchronization clock (CLK) that defines a pixel section on a line in the main scanning direction (x), and pixel recording is performed on the line in the main scanning direction by the recording signal. In the image forming apparatus to perform,
Image detection means (76a-76c) for detecting recording pixel position shifts in the main scanning direction at a plurality of locations (94a-94d, 95a-95d) on the line;
A plurality of pixels (M = 32) less than the number of inter-location pixels at the plurality of locations on the line in the main scanning direction, calculated based on the recording pixel position shifts in the main scanning direction at the plurality of locations detected using the image detecting means. Adjustment data storage means for storing pixel synchronous clock adjustment data addressed to the positions of the plurality of points in the main scanning direction for reducing each of the recording pixel position shifts in the main scanning direction at a plurality of points distributed at a pitch of (19,67);
The image recording position on the line by the main scanning, the pitch (M = 32) content of each time of change, the adjustment data read address of the memory means of the address is switched to the position addressed was the change pixel synchronizing clock adjustment data Reading means for reading (17,68,69); and
Multi-clock generating means (63) for generating a plurality of pixel synchronization clock candidates having the same period but shifted in phase, and one pixel synchronization clock corresponding to the pixel synchronization clock adjustment data read by the reading means Adjusting means (63, 66) including selecting means (66) for selecting and outputting ;
An image forming apparatus comprising:

  In addition, in order to make an understanding easy, the symbol or the corresponding matter of the corresponding element of the Example shown in drawing and mentioned later in parentheses was added as reference for reference. The same applies to the following.

Since the image detection means (76a-76c) detects the recording pixel position shift in the main scanning direction at a plurality of positions (94a-94d, 95a-95d) on the line in the main scanning direction. for example the main be calculated scanning direction of the recording pixel offset in the main scanning direction position recording pixel offset of the location more than point number (3) at a plurality of points between locations adjacent three) (2 points at a minimum) Can be obtained.

  The pixel synchronous clock adjustment data can be assigned to each pixel on one line in the main scanning direction. However, since the number of pixels on one line is several thousand, the data stored in the adjustment data storage means (19, 67) The amount becomes large. Therefore, in the embodiments described later, pixels on one line are divided by M (for example, 8, 16, 32, 64, or 128) pixel pitch, and the pixel synchronization clock adjustment data amount is set to the number of pixels on one line / M. The pixel synchronization clock adjustment data corresponding to the main scanning position is read out from the adjustment data storage means (19, 67) for every M pixels of main scanning during image formation, and the same pixel synchronization clock is applied to consecutive M pixels. The adjustment data is addressed.

For example, to reduce each of the recording pixel position shifts at a predetermined number of pixels M = 32 on the main scanning line of 4600 pixels (position of 32 pixel pitch), that is, a position of 4600/32 (about 144) . The pixel synchronization clock adjustment data (144 in total ) is stored in the adjustment data storage means (19, 67) by the image detection means (76a-76c) for each position , and the readout means (17, 68, 69). but whenever the change in the image recording position of a predetermined number of pixels M = 32 pieces of on-line by the main scanning, in accordance with the change, the adjustment data storage means (19,67) positions addressed to the read address and the change in The pixel synchronization clock adjustment data at the address is read out, and the adjustment means (63, 66) adjusts the pixel synchronization clock based on the read out pixel synchronization clock adjustment data.

Therefore, even if the pixel synchronization clock adjustment data is switched at a predetermined pixel pitch (M = 32) and the number of positions where the recording pixel positional deviation is detected is small, there are many pixel positional deviation adjustment points on one line in the main scanning direction. Adjustment of pixel position deviation on one line in the scanning direction is performed with high density.

Further, the multi-clock generating means (63), a plurality, albeit at the same cycle to generate the pixel synchronizing clock candidates whose phases are shifted from each other, by selecting one pixel synchronizing clock candidate selection means (66) Output. Therefore, the pixel synchronization clock adjustment data designates one of the plurality of pixel synchronization clock candidates that minimizes the pixel position shift.

It should be noted that, based on a plurality of locations (for example, 3 locations) detected by the image detection means (76a-76c), calculation of recording pixel positional deviations in the main scanning direction at a plurality of points (about 144 points) , and each recording pixel positional deviation obtained generation of pixel synchronizing clock adjustment data to reduce, and, writing to adjustment data storage means of the generated pixel synchronization clock adjustment data (19,67), the adjustment data generation that Oite defined below SL in the examples below Although the means (79a-79c, 17) is automatically performed, the user or operator may access the image forming apparatus with a computer such as a personal computer and use the computer. Alternatively, an operation board that is equipped or connected to the image forming apparatus may be operated by a user or an operator.

(2) The image forming apparatus according to (1), further including a driving unit (70) that supports the image detection unit (76a-76c) and drives the image detection unit (76a-76c) in the main scanning direction (x). According to this, it is possible to arbitrarily set the recording pixel position deviation detection portion. Also, can in many sets the recording pixel offset detection point, depending on the design, it is also possible to perform recording pixel offset detection over the entire length of one line in the main scanning direction. In the embodiments described later, the driving means (70) capable of detecting the recording pixel positional deviation over the entire length of one line in the main scanning direction is employed.

(3) The position control means (17), which further controls the drive means (70) to drive the image detection means to a set position on the line in the main scanning direction. Image forming apparatus.
According to this, a plurality of pixel position deviation detection locations can be set, such as a first set location and a second set location, and pixel position deviation detection by sampling is possible.

  (4) After the test image (94b, 95b) intermittently distributed in the main scanning direction for detecting the position shift is read by the image detecting means at the first set of places, the image detecting means is changed to the second set of places. The test image (94c, 95c) intermittently distributed in the main scanning direction for detecting displacement is read by the image detecting means (FIG. 14 (d), FIG. 15 (d). )), Detecting the position of each read test image in the main scanning direction, calculating the deviation of each test image from the reference position in the main scanning direction, and generating pixel synchronization clock adjustment data that minimizes the deviation, The image forming apparatus according to any one of (1) to (3), further including adjustment data generation means (79a-79c, 17) stored in the adjustment data storage means (19, 67).

  That is, the adjustment data generation means (79a-79c, 17) detects pixel position shifts at a plurality of positions on the main scanning direction line using the image detection means (76a-76c), and based on the detection value, The calculation of the recording pixel position deviation in the main scanning direction at a plurality of points, generation of pixel synchronization clock adjustment data for reducing the obtained recording pixel position deviation, and adjustment data storage means for the generated pixel synchronization clock adjustment data (19 , 67) automatically. Therefore, there is no burden on the user or operator.

  In addition, the number of samples for pixel position deviation detection can be made dense. For example, as shown in FIG. 21A, when pixel position shifts are distributed on one line in the main scanning direction X, the pixel position shift detection values at three locations Xa1d, Xb1d (center), and Xc1d are used to be adjacent. FIG. 21B is calculated by calculating the amount of positional deviation of each part of the entire line area by calculating the interpolation between the detection points and the outside of the end part by interpolation and extrapolation methods, and adjusting the positional deviation of the entire line length. ) And misalignment correction may be insufficient. According to this embodiment, the X of the test image (94b in FIG. 15 (a) / 95b in FIG. 17 (a)) at the same time at the first set of three detection points Xa1d, Xb1d and Xc1d is detected. After the position is detected, the image detecting means (76a-76c) is used to detect a pixel position shift simultaneously at the second set of three detection points Xa2d, Xb2d and Xc2d (94c / 94b in FIG. 15B). The X position of 95c) in FIG. 17B is detected, and the distance between adjacent detection points and the outside of the end points are calculated by interpolation calculation of the interpolation method and the extrapolation method on the basis of the total six points of displacement detection values. Then, when the positional deviation amount of each part in the entire line area is calculated and the positional deviation of the entire line length is adjusted, it becomes as shown in FIG. 22B, and the positional deviation is greatly reduced.

( 5 ) In an image forming apparatus that switches a recording signal addressed to a pixel in synchronization with a pixel synchronization clock that defines a pixel section on a line in the main scanning direction and performs pixel recording on the line in the main scanning direction by the recording signal.
Image detection means (76a-76c) for detecting a recording pixel position shift in the main scanning direction on the line;
Drive means (70) for supporting the image detection means and driving in the main scanning direction;
Was calculated on the basis of the main scanning direction of the recording pixel offset of the plurality of points on said image detecting means is driven in the main scanning direction in the main scanning direction detected by using the image detection means line by said drive means, the main Main scanning at each of the plurality of points for reducing each of a plurality of recording pixel positional deviations in the main scanning direction distributed at a pitch of a plurality of pixels smaller than the number of pixels between the plurality of points on the line in the scanning direction. Adjustment data storage means (19, 67) for storing pixel synchronous clock adjustment data addressed to the position in the direction;
The image recording position on the line by the main scanning, the pitch (M = 32) content of each time of change, the adjustment data read address of the memory means of the address is switched to the position addressed was the change pixel synchronizing clock adjustment data Reading means for reading (17,68,69); and
Multi-clock generating means (63) for generating a plurality of pixel synchronization clock candidates having the same period but shifted in phase, and one pixel synchronization clock corresponding to the pixel synchronization clock adjustment data read by the reading means Adjusting means (63, 66) including selecting means (66) for selecting and outputting ;
An image forming apparatus comprising:

According to this, in addition to the operational effects described in the above-mentioned “Effects of the invention”, the recording pixel positional deviation detection location can be arbitrarily set. Also, can in many sets the recording pixel offset detection point, depending on the design, it is also possible to perform recording pixel offset detection over the entire length of the main scanning direction one line. In the embodiments described later, the driving means (70) capable of detecting the recording pixel positional deviation over the entire length of one line in the main scanning direction is employed.

( 6 ) The test image (94b, 95b / 94c, 95c), which is intermittently distributed in the main scanning direction for detecting misalignment of the detected portion, is read by the image detecting means, and the position of the test image in the main scanning direction is detected. The adjustment data generating means for calculating the deviation of the test image from the reference position in the main scanning direction, generating pixel synchronous clock adjustment data that minimizes the deviation, and storing it in the adjustment data storage means (19, 67) (79a-79c, 17); The image forming apparatus according to any one of (2) to (5) .

  That is, the adjustment data generation means (79a-79c, 17) detects pixel position shifts at a plurality of positions on the main scanning direction line using the image detection means (76a-76c), and based on the detection value, The calculation of the recording pixel position deviation in the main scanning direction at a plurality of points, generation of pixel synchronization clock adjustment data for reducing the obtained recording pixel position deviation, and adjustment data storage means for the generated pixel synchronization clock adjustment data (19 , 67) automatically. Therefore, there is no burden on the user or operator.

( 7 ) In order to read the test images (94a, 94b, 94c / 95a, 95b, 95c) distributed intermittently in the main scanning direction for detecting misregistration, the drive means sets the image detection means (76a-76c). When driving in the main scanning direction, the detection signal generated by the image detection means is read, the position of the test image in the main scanning direction is detected based on the level change of the detection signal, and the main scanning direction of the test image is detected. The above (2 ) further comprising adjustment data generating means (79a-79c, 17) for calculating deviation from the reference position, generating pixel synchronous clock adjustment data for minimizing the deviation, and storing it in the adjustment data storage means The image forming apparatus according to any one of (5) to (5) .

  That is, the adjustment data generation means (79a-79c, 17) detects pixel position shifts at a plurality of positions or arbitrary positions on the main scanning direction line using the image detection means (76a-76c), and based on the detection value, Calculation of recording pixel position deviations in the main scanning direction at multiple points or multiple positions between detection points, generation of pixel synchronization clock adjustment data for reducing each recording pixel position deviation obtained, and generation of the generated pixel synchronization clock adjustment data Writing to the adjustment data storage means (19, 67) is automatically performed. Therefore, there is no burden on the user or operator.

  Further, since the detection signals generated by the image detection means are read while driving the image detection means (76a-76c) in the main scanning direction by the driving means, the pixel shift at each position in the main scanning direction is continuously detected. Therefore, the pixel shift adjustment points can be set with high density.

(8) A recording signal addressed to a pixel is switched in synchronization with a pixel synchronization clock (CLK) that defines a pixel section on a line in the main scanning direction (x), and pixel recording is performed on the line in the main scanning direction by the recording signal. In the image forming apparatus to perform,
Test image forming means (14) for forming each test image on a test surface to each of a plurality of reference positions in the main scanning direction;
Image position detecting means (76a-76c, 79a-79c, 17) for detecting the position in the main scanning direction of each test image formed on the test surface;
Adjustment data storage means (19, 67);
Calculated based on the deviation of the position of each test image detected using the image detection means with respect to each reference position , distributed at a pitch of a plurality of pixels smaller than the number of pixels between the reference positions on the line in the main scanning direction (x) In order to reduce each of the recording pixel position shifts in the main scanning direction of the plurality of points, pixel adjustment clock adjustment data addressed to the respective positions in the main scanning direction of the plurality of points is generated, and the adjustment data storage means (19, 67) adjustment data generation means (79a-79c, 17) stored in
The image recording position on the line by the main scanning, the pitch (M = 32) content of each time of change, the adjustment data read address of the memory means of the address is switched to the position addressed was the change pixel synchronizing clock adjustment data Reading means for reading (17,68,69); and
Multi-clock generating means (63) for generating a plurality of pixel synchronization clock candidates having the same period but shifted in phase, and one pixel synchronization clock corresponding to the pixel synchronization clock adjustment data read by the reading means Adjusting means (63, 66) including selecting means (66) for selecting and outputting ;
An image forming apparatus comprising:

According to this, in addition to the operational effects described in the above “Effects of the invention”, the adjustment data generating means (79a-79c, 17) can provide many main scanning positions on one line in the scanning direction. Pixel synchronization clock adjustment data that reduces the recording pixel position deviation in the main scanning direction is generated and written to the adjustment data storage means (19, 67). Accordingly, the pixel synchronization clock adjustment data at the main scanning position can be read to automatically adjust the pixel clock. By increasing the number of pixel position deviation adjustment points on one line in the main scanning direction, it is possible to adjust the pixel position deviation on one line in the main scanning direction with high density.

( 9 ) The image forming apparatus further includes temperature detection means (61a-61c, 62a-62c); the adjustment data storage means (19, 67) is a pixel synchronous clock adjustment data group (for example, 1 ) addressed to each of the plurality of temperature sections. The group holds 144 data) , and the reading means (17, 68, 69,) stores the data of the pixel synchronous clock adjustment data group addressed to the temperature section to which the temperature detected by the temperature detecting means belongs. The image forming apparatus according to any one of (1) to ( 8 ), wherein reading is performed from the adjustment data storage unit (19, 67).

When image forming use by the image forming apparatus is started, as shown in FIG. 20B, the temperature in the image forming apparatus rises with time and the pixel position shift amount in the main scanning direction changes. In this embodiment, since the pixel synchronization clock adjustment data corresponding to the temperature in the image forming apparatus is used for the pixel position deviation adjustment, the reliability of the pixel position deviation adjustment can be increased even if there is a temperature variation.

( 10 ) The read-out means (17, 68, 69,) is arranged such that when the detected temperature of the temperature detection means (61a-61c, 62a-62c) has changed from the previous temperature, the adjustment data storage means ( 19, 67) is switched to the data group addressed to the temperature category to which the detected temperature belongs, and the previous temperature is updated to the detected temperature (12, 13 in FIG. 9). The image forming apparatus according to ( 9 ) above. According to this, when there is no temperature change, the pixel synchronous clock adjustment data group is not switched. This eliminates unnecessary switching work of the pixel synchronous clock adjustment data group .

In an example described later, the temperature region is a first region of 10 ° or less, a second region of over 10 ° and 20 ° or less, a third region of over 20 ° and 30 ° or less, and a third region of over 30 ° and 45 ° or less. 4 areas and a fifth area exceeding 45 ° are divided into five areas. For example, if the detected temperature changes from the second area to the third area, the adjustment data storage means (19 the reading of the pixel synchronizing clock adjustment data from 67), a second region addressed group (group; switching from a table) in the third area addressed group (group).

(11) an image forming apparatus, a temperature detecting means (61a-61c, 62a-62c ), and further comprising detecting location storage means (19) for storing a positional deviation detecting portion of the temperature classification are addressed; said position control means (17) reads out the detection location (94b, 95b / 94c, 95c) addressed to the temperature category to which the temperature detected by the temperature detection means belongs from the detection location storage means (19), and displays an image on the detection location. The image forming apparatus according to any one of (1) to (10), wherein the detection unit (76a-76c) is driven.

  For example, as shown in FIG. 21A, when pixel position shifts are distributed on one line in the main scanning direction X, the pixel position shift detection values at three locations Xa1d, Xb1d (center), and Xc1d are used to be adjacent. FIG. 21B is calculated by calculating the amount of positional deviation of each part of the entire line area by calculating the interpolation between the detection points and the outside of the end part by interpolation and extrapolation methods, and adjusting the positional deviation of the entire line length. ) And misalignment correction may be insufficient. In this case, the misalignment is detected at the midpoint Xa2d between Xa1d and Xb1d and at the midpoint Xb2d between Xb1d and Xc1d, and the position misalignment of each part of the entire line area is calculated based on the detected value. When the positional deviation is adjusted, it becomes as shown in FIG. 21C, and the positional deviation is greatly reduced. However, since the positional deviation distribution on the line (for example, FIG. 21A) also depends on the temperature, it is preferable to determine the position where the positional deviation is detected corresponding to the temperature. According to the present embodiment, it is possible to automatically set a detection portion that can cope with temperature and can reduce the positional deviation of each portion of one line in the main scanning direction.

(12) The image forming apparatus transfers the electrostatic latent image on the photosensitive member by switching the laser recording pixel recording signal synchronized with the pixel synchronization clock between the main scanning direction laser scanning on the photosensitive member and the scanning. A frequency adjusting means for adjusting the frequency of the original clock (output of 61) so that the number of pixels in one line of laser scanning is set as a set value; and the multi-clock generating means (63 ) Frequency-divides the original clock whose frequency is adjusted, and outputs a plurality of frequency-divided signals having the same period but relatively shifted in phase by an integer period of the original clock (63) The image forming apparatus according to any one of (1) to (11) above. According to this, the number of pixels (line length magnification) on each main scanning line becomes the same.

(13) The pixel synchronization clock adjustment data of the adjustment data storage means (19, 67) is addressed to each division obtained by dividing the number of pixels in one line of laser scanning by two or more M pixel pitches; The readout means (17, 68, 69) includes a second frequency dividing means (69) for dividing the pixel synchronous clock output from the selection means (66) into 1 / M and a clock divided into 1 / M. The pixel synchronization clock adjustment data associated with the count data of the counting means is read from the adjustment data storage means (67); any one of (1) to (12) above the image forming apparatus according to one or. According to this, the amount of pixel synchronization clock adjustment data becomes the number of pixels on one line / M, and the amount of data stored in the adjustment data storage means (19, 67) can be suppressed.

(14) The image forming apparatus is a color printer that includes a plurality of image forming units that form images of a plurality of colors and forms a color image on a transfer sheet by superimposing the images of the plurality of colors; The means (79a-79c, 17) forms the test image on the test surface for each of a plurality of colors, generates the pixel synchronous clock adjustment data, and stores it in the adjustment data storage means; The image forming apparatus according to 4), (6), (7) or (8) . According to this, the color shift of the color print is reduced. The pixel position shift of each color can be detected with high accuracy.

(15) The image forming apparatus is a color printer that includes a plurality of image forming units that form images of a plurality of colors and forms a color image on a transfer sheet by superimposing the images of the plurality of colors; The means (79a-79c, 17) is formed by arranging test images of a plurality of colors in the main scanning direction on the test surface, reading each color test image on the same test surface, and reading the pixel synchronization clock adjustment data for each color. The image forming apparatus according to (4), (6), (7) or (8) above, wherein the image data is generated and stored in the adjustment data storage means. According to this, the color misregistration of the color print is reduced. Since the pixel position shift of each color is detected at once, the time required for pixel position shift detection for generating adjustment data can be shortened.

(16) The image forming apparatus according to (14) or (15) above;
Imaging means (10) for generating color component image data of an image having an imaging element and projected thereon; and
An image data processing device (ACP) that converts the color component image data generated by the imaging means (10) into image data for color image formation of the color image forming device and outputs the image data to the color image forming device;
A color image forming apparatus comprising: According to this, the image read by the imaging means (10) can be printed out by the image forming apparatus.

(17) The image forming apparatus according to (14) or (15) above; and
A color image forming apparatus comprising: an image data processing apparatus (ACP) that converts document information instructed by an external device (PC) to print image data suitable for the image forming apparatus and outputs the converted image data to the image forming apparatus. According to this, it is possible to print out document information instructed to be printed by an external device (PC).

(18) The image forming apparatus according to (14) or (15) above;
Imaging means (10) for generating color component image data of an image having an imaging element and projected thereon; and
Color component image data generated by the imaging means is converted into image data for color image formation of the color image forming apparatus and output to the color image forming apparatus, and document information instructed to be printed by an external device (PC), An image data processing apparatus (ACP) that converts the image forming apparatus into record image data suitable for output to the image forming apparatus;
A color image forming apparatus comprising:

  Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

  FIG. 1 shows a multi-function full-color digital copying machine according to a first embodiment of the present invention. This full-color copying machine is roughly constituted by units of an automatic document feeder (ADF) 13, an operation board 20, a color scanner 10, a color printer 14 and a finisher 100. The operation board 20, the color scanner 10 with the ADF 13, and the finisher 100 are units that can be separated from the printer 14. The color scanner 10 includes a control board having a power device driver, a sensor input, and a controller. 14 communicates directly or indirectly with the image data processing device ACP (FIG. 6) of the control board 14 in the machine to read the document image under timing control.

  The image data processing apparatus ACP (FIG. 6) is connected to a LAN (Local Area Network) connected to a personal computer PC, and the facsimile control unit FCU (FIG. 6) is connected to a telephone line PN (facsimile communication line). The exchange PBX is connected. The printed paper of the color printer 14 is discharged to the finisher 100.

  FIG. 2 shows the mechanism of the color printer 14. The color printer 14 of this embodiment is a laser printer. An assembly (image forming unit) of a photoconductor 56 and a developing device 55 and a charger, a cleaning device, and a transfer device (illustration unit) (not shown) that forms a one-color toner image is M (magenta), C (cyan), Y ( Yellow) and Bk (black) for each image formation, there are 4 sets in total, arranged in tandem along the conveying belt 57 in this order, and each color toner image formed by them is sequentially It is transferred onto a single sheet of transfer paper.

  The transfer sheets stacked on the first tray 48, the second tray 49, and the third tray 50 are fed by the first paper feeding device 51, the second paper feeding device 52, and the third paper feeding device 53, respectively, and are conveyed vertically. The unit 54 is transported to a position where it abuts against the photoreceptor 56.

  The image data read by the scanner 10 is corrected by the image data processor IPP (FIG. 6), once written in the memory MEM (FIG. 6), read, and using the read image data in FIG. By the laser exposure from the writing unit 30, writing is performed on the uniformly charged photoreceptor 56 by a charger (not shown), thereby forming an electrostatic latent image. As the electrostatic latent image passes through the developing unit 55, a toner image appears on the photoreceptor 56. The toner image on the photoconductor 56 is transferred while the transfer paper is conveyed by the conveyance belt 57 at the same speed as the rotation of the photoconductor 56. Thereafter, the image is fixed by the fixing unit 58 and discharged by the paper discharge unit 59 to the finisher 100 of the post-processing apparatus.

  A light-reflective sensor (hereinafter referred to as a test image sensor) 76a for detecting a pixel recording deviation (partial magnification) at a predetermined position on a line in the main scanning direction x (perpendicular to the paper surface of FIG. 2) of each color image recording. A driving device 70 that supports ˜76c (FIG. 7) and can be driven in the main scanning direction x is above the roller Rs that indicates the conveying belt 57. The configuration of the driving device 70 will be described later with reference to FIG.

  The finisher 100 of the post-processing apparatus shown in FIG. 2 can guide the transfer paper conveyed by the paper discharge unit 59 of the main body in the normal paper discharge roller 103 direction and the staple processing unit direction. By switching the switching plate 101 upward, the sheet can be discharged to the normal discharge tray 104 side via the transport roller 103. Further, by switching the switching plate 101 downward, the switching plate 101 can be conveyed to the staple table 108 via the conveying rollers 105 and 107. The transfer paper loaded on the staple table 108 is aligned by the paper jogger 109 every time one sheet is discharged, and is bound by the stapler 106 upon completion of partial copying. The group of transfer sheets bound by the stapler 106 is stored in the staple completion discharge tray 110 by its own weight.

  On the other hand, the normal paper discharge tray 104 is a paper discharge tray that can move back and forth (in a direction perpendicular to the paper surface of FIG. 2). The paper discharge tray section 104 that can be moved back and forth moves forward and back for each original or each copy section sorted by the image memory, and simply sorts the discharged copy paper. When images are formed on both sides of the transfer paper, the transfer paper fed from each of the paper feed trays 48 to 50 is not guided to the paper discharge tray 104 side, and the branching claw 60 for switching the path is used. By turning it downward, it is once guided to the reversing unit 112 and then stocked in the duplex feeding unit 111.

  Thereafter, the transfer paper stocked on the double-sided paper feed unit 111 is again fed from the double-sided paper feed unit 111 to transfer the toner image formed on the photosensitive member 56, and the branching claw for switching the path. 60 is returned to the illustrated horizontal position and guided to the paper discharge tray 104. In this way, when creating images on both sides of the transfer paper, the reversing unit 112 and the duplex feeding unit 111 are used.

  The photoconductor 56, the conveyance belt 57, the fixing unit 58, the paper discharge unit 59, and the development unit 55 are driven by a main motor (not shown), and each of the paper feeding devices 51 to 53 is also not shown. It is driven by being transmitted by each sheet feeding clutch. The vertical conveyance unit 54 is driven by transmitting the drive of the main motor by an intermediate clutch (not shown).

  FIG. 3 is an enlarged plan view of the optical unit constituting the writing unit (writing optical system) 30 in FIG. 2 as viewed from above. In the figure, light beams from a laser diode unit (LD unit) 31bk and an LD unit 31m including a laser diode and a laser driver that modulates the laser light pass through cylinder lenses 32bk and 32m, and are reflected by a reflecting mirror 33bk and a reflecting mirror 33m. Is incident on the lower surface of the polygon mirror 34, and the polygon mirror 34 rotates to deflect the light beam, pass through the fθ lens 35ybk and the fθ lens 35mc, and is folded back by the first mirror 36bk and the first mirror 36m. It is.

  On the other hand, the light beams from the LD unit 31y and the LD unit 31c pass through the cylinder lenses 32y and 32c and enter the upper surface of the polygon mirror 34, and the polygon mirror 34 rotates to deflect the light beam, and the fθ lens. The light passes through 35ybk and the fθ lens 35mc and is folded by the first mirror 36y and the first mirror 36c.

  Cylinder mirrors 37ybk and 37mc and sensors 38ybk and 38mc are provided on the upstream side from the writing position in the main scanning direction. It is configured to be incident on the sensors 38ybk and 38mc. These sensors 38ybk and 38mc are synchronization detection sensors for synchronizing in the main scanning direction.

  In the detection of the light beams from the LD units 31bk and 31y, a common sensor 38ybk is used on the writing side. Similarly, for the detection of the light beams from the LD units 31m and 31c, a common sensor 38mc is used on the writing side. Since two color imaging light beams are incident on the same sensor, the timing at which each light beam is incident on each sensor can be set by making the incident angles of the polygon mirrors 34 different from each other. Instead, it is output as a pulse train in time series. As can be seen from the figure, K (bk) and Y (y) and M (m) and C (c) are scanned in the opposite directions.

  In the present embodiment, the thermocouple temperature sensors 61a to 61c and 62a to 62c are added to the fθ lenses 35mc and 35ybk because the pixel position shift (partial magnification) in the main scanning direction varies greatly due to the temperature change of the fθ lenses 35mc and 35ybk. Equipped with.

  FIG. 4 shows the configuration of the image writing control unit 16 c in the image forming unit 16 (FIG. 6) of the color printer 14. The print image control units 25m, 25c, 25y and 25k addressed to the magenta M, cyan C, yellow Y and black K color image signals control the entire write control unit 16c by the command of the CPU of the process controller 17, and write The image signals M, C, Y and K output from the image signal generation of each color writing I / F of the built-in I / F 15 (FIG. 6) are transferred to the laser drive circuits 23m, 23c, 23y and 23k.

  In the following, in order to simplify the description, the component component codes m, c, y, and k are omitted and the element codes are shown.

  The write clock generation circuit 21 sends to the phase synchronization circuit 22 an original clock OCL having a frequency higher than the frequency of the clock CLK having a period in units of main scanning pixels. The phase synchronization circuit 22 includes a laser detection signal DETk, DETc, DETm, DETy for each color image separated from the laser detection signals of the synchronization detection sensors 38ybk and 38mc by signal separation processing, and a write clock generation circuit 21. 16 sets (16 series) of pixel synchronization clock candidates CLK0 to CLK15 generated by dividing the clock OCL in two stages are supplied.

FIG. 5 shows an outline of functional configurations of the write clock generation circuit 21 and the phase synchronization circuit 22. The frequency adjusting circuit 61 of the write clock generating circuit 21 generates an intermediate clock having a frequency specified by the frequency control data provided by the frequency control data latch 62 from the original clock OCL, supplies the intermediate clock to the frequency divider 63, and outputs the intermediate clock. pulses of the clock by 1/16 minutes, the pixel synchronizing clock first candidate frequency divider 63 is output; (output of the first output port 0 of the frequency divider 63 a clock and the intermediate clock to 1/16 min) The phase of the intermediate clock is controlled by PLL control so as to be in phase. In the frequency control data latch 62, the controller 17 sets (latches) frequency control data in which the frequency of the pixel synchronization clock first candidate is a frequency corresponding to the number of set pixels on one main scanning line. Thereby, the line length (line length magnification) of each main scanning line becomes constant.

  The frequency divider 63 of the write clock generation circuit 21 outputs the pixel synchronization clocks from the first candidate (reference pixel synchronization clock) to the sixteenth candidate to each of the output ports 0 to 15 in parallel. These first to sixteenth candidate pixel synchronization clocks are obtained by dividing the intermediate clock by 1/16 and have the same period (same frequency). However, the phase is shifted by one period of the intermediate clock. In other words, the pixel synchronization clocks of the first to sixteenth candidates are sequentially shifted in phase by 1/16 of their period. By selecting one candidate from the first to sixteenth candidates and using it as the pixel synchronization clock, and switching the candidate to be selected, the pixel position deviation can be adjusted to the minimum. For example, when the pixel synchronization clock CLKo shown in FIG. 19A is used as the output of the eighth output port 7 of the frequency divider 63 (eighth candidate: reference pixel synchronization clock), a test image is created. Assuming that an image indicated by a dotted line is formed in (b) of FIG. 6B and shifted from the reference position indicated by a solid line, by switching the pixel synchronization clock to a candidate that minimizes the shift for each period of the pixel synchronization clock, The pixel position shift (partial magnification) in the main scanning direction on the main scanning line is minimized (constant).

  The phase synchronization circuit 22 has 22k, 22c, 22m, and 22y for each color K, C, M, and Y, but the functional configuration is the same. Therefore, only the outline of the functional configuration of the phase synchronization circuit 22k is shown in FIG.

The internal synchronization signal generation circuit 64 of the phase synchronization circuit 22 (22k), when the number of intermediate clocks specified by the line end instruction data of the switching timing data latch 65 is generated after the laser detection signal DET (k) is generated. Next, the line synchronization signal LSY (k) that defines the writing start point in the main scanning direction is switched to a valid level (synchronization instruction level), and then maintained at a significant level for a predetermined period (a predetermined number of intermediate clocks) and then invalidated. Return to level. In addition, after the image forming start signal is supplied from the controller 17, a predetermined time from the line synchronization signals LSYk, LSYc, LSYm, and LSYy in which the number of line synchronization signals L specified by the page leading instruction data of the switching timing data latch 65 is generated. Later, the laser drive circuits 23k, 23c, 23m, and 23y start laser writing (line writing). The processor 17 determines the line leading edge instruction data and the page leading edge instruction data set in the timing data latch 65 so that the leading edge of each color line image by writing of each color is in the same position in the x and y directions on the transport belt 57. (7, 9 in FIG. 9 ). As a result, the image forming start point (the leading pixel of the line) in the sub-scanning direction y (first line of the page) and the main scanning direction x in each color image can be made uniform.

  The selection gate 66 of the phase synchronization circuit 22 (22k) is supplied with the pixel synchronization clock first to 16th candidates output from the frequency divider 63 of the write clock generation circuit 21. The selection gate 66 outputs the candidate designated by the adjustment data output from the selection data memory 67 among the first to sixteenth candidates to the laser drive circuit 23 (k) as the pixel synchronization clock CLK (k). Although details will be described later, an adjustment data table is stored in the adjustment data table (memory area) of the nonvolatile memory 19 (FIG. 6) according to the classification of the temperature area and the recording color, and the processor detects the detection temperature area (classification) and the recording. One adjustment data group corresponding to the color is read from the nonvolatile memory 19 (FIG. 6) and written to the selection data memory 67. Adjustment data of 1 / M (for example, M = 32) of a predetermined number of pixels (for example, 4600) of one line length in the main scanning direction is one adjustment data group, and during normal image formation, the frequency divider 69 performs pixel synchronization. Each time the clock CLK (k) is counted and M pixel synchronization clocks are counted, a data update pulse is output, and the address counter 68 counts up this pulse to select the adjustment data corresponding to the count value as the selected data. Output from the memory 67 to the selection gate 66. Note that, at the time of test image creation for position shift detection, which will be described later, only the adjustment data designating the reference pixel synchronization clock (output of the output port 7 of the frequency divider 63: eighth candidate) is supplied to the selection gate 66. This is given to the selection gate 66.

  FIG. 6 shows the system configuration of the image processing system of the copying machine shown in FIG. In this system, a color document scanner 10 including a reading unit 11 and an image data output I / F (Interface) 12 is connected to an image data interface control CDIC (hereinafter simply referred to as CDIC) of an image data processing apparatus ACP. Yes. A color printer 14 is also connected to the image data processing apparatus ACP. The color printer 14 receives the recorded image data from the image data processor IPP (Image Processing Processor; hereinafter simply referred to as IPP) of the image data processing apparatus ACP to the writing I / F 15 and prints it out by the image forming unit 16. . The image forming unit 16 is shown in FIG.

  The image data processing device ACP (hereinafter simply referred to as ACP) includes a parallel bus Pb, an image memory access control IMAC (hereinafter simply referred to as IMAC), a memory module MEM (hereinafter simply referred to as MEM) as an image memory, a program And a hard disk device HDD (hereinafter simply referred to as HDD) for storing and storing document information, a system controller 1, RAM 4, nonvolatile memory 5, font ROM 6, CDIC, IPP, and the like. A facsimile control unit FCU (hereinafter simply referred to as FCU) is connected to the parallel bus Pb. The operation board 20 is connected to the system controller 1.

  The reading unit 11 for optically reading the original of the color original scanner 10 photoelectrically converts the reflected light of the lamp irradiation on the original with a CCD on a sensor board unit SBU (hereinafter simply referred to as SBU). , B image signals are generated, converted to RGB image data by an A / D converter, shading corrected, and sent to the CDIC via the output I / F 12.

  The CDIC performs data transfer between the document scanner 10 (output I / F 12), the parallel bus Pb, and the IPP, and communication between the process controller 17 and the system controller 1 that controls the entire ACP. The RAM 18 is used as a work area for the process controller 17, and the nonvolatile memory 19 stores an operation program for the process controller 17.

  An image memory access control IMAC (hereinafter simply referred to as IMAC) controls writing / reading of image data to / from the MEM or HDD. The system controller 1 controls the reading and writing of data other than document information such as programs and control data with respect to the HDD, and controls the operation of each component connected to the parallel bus Pb. The RAM 4 is used as a work area for the system controller 1, and the nonvolatile memory 5 stores an operation program for the system controller 1.

  The operation board 20 instructs processing to be performed by the ACP. For example, the type of processing (copying, facsimile transmission, image reading, printing, etc.), the number of processings, etc. are input. Thereby, the image data control information can be input.

  The image data read from the reading unit 11 of the scanner 10 is subjected to shading correction 210 by the SBU of the scanner 10 and then subjected to image processing for correcting reading distortion such as scanner gamma correction and filter processing by IPP. Accumulate in MEM or HDD. When printing out MEM or HDD image data, IPP performs color conversion of RGB signals to YMCK signals, printer gamma conversion, gradation conversion, and image quality processing such as gradation processing such as dither processing or error diffusion processing. Do it. The image data after the image quality processing is transferred from the IPP to the writing I / F 15. The writing I / F 15 performs laser control on the gradation-processed signal by pulse width and power modulation. Thereafter, the image data is sent to the image forming unit 16, and the image forming unit 16 forms a reproduced image on the transfer paper.

  Based on the control of the system controller 1, the IMAC controls the access of image data to the MEM and HDD, develops print data of a personal computer PC (not shown) connected to the LAN (hereinafter simply referred to as PC), Compress / decompress image data for effective use.

  The image data sent to the IMAC is stored in the MEM and HDD after data compression, and the stored image data is read out as necessary. The read image data is decompressed, returned to the original image data, and returned from the IMAC to the CDIC via the parallel bus Pb. After the transfer from the CDIC to the IPP, the image quality processing is performed and output to the writing I / F 15, and a reproduced image is formed on the transfer paper in the image forming unit 16.

  In the flow of image data, the functions of the digital multi-function peripheral are realized by the bus control by the parallel bus Pb and the CDIC. Facsimile transmission is performed by performing image processing on the read image data by IPP and transferring it to the FCU via the CDIC and the parallel bus Pb. The FCU performs data conversion to the communication network and transmits it as facsimile data to the public line PN. Facsimile reception is performed by converting line data from the public line PN into image data by the FCU and transferring it to the IPP via the parallel bus Pb and CDIC. In this case, no special image quality processing is performed, and the image is output from the writing I / F 15 and a reproduced image is formed on the transfer paper in the image forming unit 16.

  In a situation where a plurality of jobs, for example, a copy function, a facsimile transmission / reception function, and a printer output function operate in parallel, the usage rights of the reading unit 11, the image forming unit 16, and the parallel bus Pb are assigned to the system controller 1 and the process. Control is performed by the controller 17. The process controller 17 controls the flow of image data, and the system controller 1 controls the entire system and manages the activation of each resource. The function selection of the digital multi-function peripheral is performed on the operation board 20, and processing contents such as a copy function and a facsimile function are set by a selection input of the operation board 20.

  The system controller 1 and the process controller 17 communicate with each other via parallel buses Pb, CDIC, and serial bus Sb. Specifically, communication between the system controller 1 and the process controller 17 is performed by performing data format conversion for data and interface between the parallel bus Pb and the serial bus Sb in the CDIC.

  Various bus interfaces, such as a parallel bus I / F 7, a serial bus I / F 9, a local bus I / F 3, and a network I / F 8, are connected to the IMAC. The controller unit 1 is connected to related units via a plurality of types of buses in order to maintain independence in the entire ACP.

  The system controller 1 controls other functional units via the parallel bus Pb. The parallel bus Pb is used for transferring image data. The system controller 1 issues an operation control command for storing image data in the MEM to the IMAC. This operation control command is sent via IMAC, parallel bus I / F 7, and parallel bus Pb.

  In response to this operation control command, the image data is sent from the CDIC to the IMAC via the parallel bus Pb and the parallel bus I / F 7. Then, the image data is stored in the MEM under the control of the IMAC.

  On the other hand, the ACP system controller 1 functions as a printer controller, network control, and serial bus control in the case of a call from the PC as a printer function. In the case of via the network, the IMAC receives print output request data via the network I / F 8.

  Print output request data from the PC is developed into image data by the system controller 1. The development destination is an area in MEM. Font data necessary for expansion is obtained by referring to the font ROM 6 via the local bus I / F 3 and the local bus Rb. The local bus Rb connects the controller 1 to the nonvolatile memory 5 and the RAM 4. Regarding the serial bus Sb, in addition to the external serial port 2 for connection with the PC, there is also an interface for transfer with the operation board 20 which is an operation unit of the ACP. This is not print development data, but communicates with the system controller 1 via the IMAC, accepts processing procedures, displays the system status, and the like. Data transmission / reception between the system controller 1 and the MEM, HDD, and various buses is performed via the IMAC. Jobs that use MEM and HDD are centrally managed in the entire ACP.

FIG. 7 shows the arrangement positions of the test image sensors 76 a to 76 c supported by the driving device 70 (FIG. 2) with respect to the conveyance belt 57. The sensors 76 a to 76 c are arranged on the same straight line extending in the main scanning direction x, fixed to the support frame 75, and above the roller Rs that supports the conveyance belt 57. The support frame 75 is fixed to a screw rod 74 that extends parallel to the main scanning direction x. The screw rod 74 is screw-coupled to the feed nut in the speed reducer 71 and passes through it. There is a gear distributed along the circumference on the outer circumference of the nut, and the pulse motor 72 rotationally drives a drive gear meshing with the gear. A rotary encoder 73 is coupled to the rotation shaft of the pulse motor 72 and generates one rotation synchronization pulse for each rotation of the pulse motor 72 at a predetermined small angle. A base point index 78 is provided on the back surface of the support frame 75, and a reflection type optical sensor 77 for detecting this is mounted on the outer surface of the speed reducer 71. By driving the pulse motor 72 forward and backward, the test image sensors 76a to 76c are driven and positioned at the positions shown in FIGS. 14 to 17, and the main scanning drive is performed in the direction indicated by the arrow in the figure. Test images 94a to 94d and 95a to 95d formed on the conveyor belt 57 can be read.

  Referring to FIG. 8, test bar reading circuits 79a to 79c process test image reading signals of the test image sensors 76a to 76c. The functional configurations of the test image sensors 76a to 76c are the same, and therefore the functional configurations of the test bar reading circuits 79a to 79c are also the same. When reading a test image, the controller 17 gives the D / A converter 91 energization data specifying the energization current value of the light emitting diode (LED) 85 of the optical sensor 76 (a), and the D / A converter 91 applies it. The analog voltage is converted and applied to the LED driver 86. The LED driver 86 supplies a current proportional to the analog voltage to the LED 85. The light generated by the LED 85 hits the transfer belt 57 through a slit (not shown) inclined by 45 ° in the main scanning direction x, and most of the light is reflected by the transfer belt 57 and hits the phototransistor 87 through the slit. As a result, the impedance between the collector and emitter of the transistor 87 becomes low, and the emitter potential rises. By driving the test image sensors 76a to 76c in the main scanning direction x (for example, the direction of the thick arrow in FIGS. 14 to 17), the test images 94a to 94d and 95a to 95d (lines inclined by 45 ° in the main scanning direction x). When the test image absorbs light when it reaches the position facing the LED 85, the amount of light received by the transistor 87 is reduced, and the collector / emitter becomes high impedance. The level of the detection signal in (a) decreases. Therefore, when a test pattern is formed on the transfer belt 57 and the test image sensor 76 (a) is driven in the main scanning direction x, the detection signal of the test image sensor 76 (a) varies in level. A high voltage means no test image, and a low voltage means a test image is present.

  The detection signal of the test image sensor 76 (a) is further calibrated to 0 to 5 V by an amplifier 89 for level calibration through a low-pass filter 88 for removing high frequency noise, and applied to the A / D converter 90. The The calibrated detection signal is also supplied to the window comparator 93 through the amplifier 92.

  The A / D converter 90 includes a sample hold circuit on the input side thereof and a data latch (output latch) on the output side thereof. When the controller 17 gives the A / D conversion instruction signal Scr, the detection signal at that time The voltage is held, converted into digital data, and held in the data latch. Therefore, the controller 17 can read the digital data representing the level of the detection signal, that is, the detection data Ddr by giving the instruction signal Scr when the detection signal needs to be read.

The window comparator 93 generates a level determination signal Swf of a low level L when the detection signal is within a range of 2V or more and 3V or less, and a high level H when the detection signal is outside the range. The controller 17 can immediately recognize whether or not the detection signal is within the range by referring to the level determination signal Swf. Test image sensor 76 that Mashimasu viewing the test image presence of (a) a low level L (1V so), the constant speed movement in the main scanning direction x of the test image sensor 76 (a), the test image sensor 76 The detection signal (a) causes a level fluctuation.

FIG. 18A shows an enlarged part of the fluctuation. In this case, the descending region where the level of the test image detection signal is reduced corresponds to the leading edge region in the x direction of the test image, and the ascending region corresponding to the rising edge corresponds to the trailing edge region of the test image in the x direction. The region between the descending region and the ascending region is the region of the test image width w. When reading the test image, the controller 17 drives the test image sensor 76 (a) at a constant speed in the direction of the arrow shown in FIGS. 14 to 17 while testing the field of the test image sensor 76 (a). In the process in which the detection signal changes from H to L when the image arrives, the window comparator 93 in FIG. 8 waits for the detection signal Swf = L indicating that the detection signal is 2 to 3V, When Swf = L, the A / D conversion is instructed to the A / D converter 90 repeatedly at a predetermined period while Swf = L, and A / D conversion data is read. The controller 17 reads the A / D conversion data described above during the main scanning drive of the test image sensor 76 (a) during the set range (the range of the length of the arrow shown in FIGS. 14 to 17). .

  As shown in FIG. 18B, the center position a of the descending area where the level of the test image detection signal is lowered and the center position b of the ascending area which is rising next is within the range of 2V to 3V. Is the center position of one test image in the x direction, and similarly, the center position c of the descending region where the level of the test image detection signal that appears next to the center point c decreases, and the next rise The middle point Ayrp of the center position d of the rising area is the center position in the x direction of another test image. The controller 17 calculates the x position (the center position in the x direction) of each test image (line image extending in the y direction) based on the read A / D conversion data.

  Referring again to FIG. 8, the controller 17 gives a normal rotation, reverse rotation, and stop instruction to the motor driver 80 that rotationally drives the pulse motor 72 to control the driving of the motor 72 (the driving of the sensor 76 in the x direction). The position counter 81 counts the rotation synchronization pulse generated by the rotary encoder 73. The position counter 81 counts up the rotation synchronization pulse while the controller 17 gives the forward rotation instruction to the motor driver 80, and issues the reverse rotation instruction. Count down while giving. When the optical sensor 77 detects the base point index 78, the count value is initialized. That is, it is set to a value (for example, 0) indicating the base point position. The controller 17 gives a normal rotation, reverse rotation, and stop instruction to the motor driver 80, monitors the transition of the count data of the position counter, and drives and stops (positioning) the test image sensor 76 (a) to the set position. Controls x-direction constant speed drive (x scan) for test image reading and return to the base point (78).

  Thermocouple temperature sensors 61 a to 61 c and 62 a to 62 c shown in FIG. 3 are connected to the temperature reading circuits 83 and 84. When there is a temperature data output request from the controller 17, the temperature reading circuit 83 digitally converts and reads the detection signals of the three sensors 61a to 61c, calculates an average value, and the deviation is large with respect to the average value. When there is temperature data, the average value excluding the temperature data is calculated, the average value data is updated, and the average value data is output to the controller 17. The configuration and operation of the temperature reading circuit 84 are the same as those of the temperature reading circuit 83.

  FIG. 9 shows an overview of image formation control of the controller 17 mainly focusing on color misregistration search and color misregistration adjustment. When the power is turned on and an operating voltage is applied to the controller 17, the controller 17 sets the internal state of the controller 17 to an initial state and sets the input / output port for the outside of the controller to a standby state (step 1). In the following, the word “step” is abbreviated in parentheses, and step no. Write numbers only.

Next, the controller 17 reads the internal state of the printer 14 and the command from the system controller 1 (FIG. 6) (2). In this “status reading” (2), when a state in which printing operation cannot be performed is detected, an abnormality is displayed on the operation board 20 via the system controller 1 (3, 4). If there is no abnormality, the temperature detection circuits 83 and 84 are requested to obtain temperature data, an average value of the temperature values represented by the temperature data output from the circuits 83 and 84 is calculated, and the average value is converted into temperature region data. Convert. That is, in this embodiment, the temperature region is a first region of 10 ° or less, the second region of over 10 ° and 20 ° or less, the third region of over 20 ° and 30 ° or less, and the third region of over 30 ° and 45 ° or less. 4 regions and a 5th region exceeding 45 ° are divided into 5 regions, and the temperature region data representing the region to which the calculated average value belongs is determined by determining which of the first to fifth regions the temperature region belongs to. Is generated. Then, the page end instruction data and the line end instruction data addressed to the generated temperature region in the nonvolatile memory 19 are read out and set in the switching timing data latch 65 of the phase synchronization circuits 22k, 22c, 22m, 22y. Moreover, the adjustment data table of the nonvolatile memory 19, and reads out the color adjustment data group generated temperature region destined writes phase synchronization circuit 22k, 22c, 22m, the selection data memory 67 22y.

  In the next “input reading” (5), the controller 17 waits for an operator or user input to the operation board 20 and a command from the system controller 1, and when there is an input, performs processing corresponding to the input. Upon receiving an “image shift search” instruction in this “input reading” (5), the controller 17 executes “image shift search” (7).

  FIG. 10 shows an outline of processing of “image shift search” (7). First, temperature data is requested from the temperature detection circuits 83 and 84, and an average value of temperature values represented by the temperature data output from the circuits 83 and 84 is calculated and held (21). Next, depending on which mode is specified, standard search (“fine”, “medium” or “coarse”) or simple search (“simple fine”, “simple medium” or “simple coarse”) The test pattern image corresponding to the mode is formed on the conveying belt 57. Note that the default mode is simple search (“simple secret”), but other modes can be specified (set) using the operation board 20 or the property selection function of the personal computer.

  When the standard search (“fine”, “medium”, or “coarse”) mode is designated, the controller 17 first sets the seventh pixel synchronization clock candidate (frequency divider) to the selection gate (66) of each of the phase synchronization circuits 22k to 22y. 63, the output clock of the seventh output port 7), and the test images 96 and 97 for searching for the line shift and the test image 94a for searching for the Bk pixel position shift shown in FIG. An image is formed (23). Test screen information with these test images is stored in the HDD, and the system controller 1 reads the mode-compatible test screen information from the HDD via the IMAC and outputs it to the printer 14 via the CDIC.

  A test image 96 for searching for line deviation is an image in which Bk, C, M, and Y line images, which are inclined by 45 ° with respect to the main scanning direction x, are arranged in this order in the y direction. One group is formed at positions 76a, 76b and 76c, and a total of three groups. These test images 96 are read by driving the conveyor belt 57 at a constant speed in the paper feeding direction (24 in FIG. 10). If the line position at the front end of each color image page is the same, the test image 96 is detected so that the distance of each subsequent line from the Bk line at the front end in the y direction is the same as the reference value. The difference in the detection distance with respect to the reference value includes image forming position shifts (shifts in the sub-scanning direction) of other colors with respect to Bk in the sub-scanning direction y. However, the shift amount in the main scanning direction x of the line tip (line writing start end) of another color with respect to Bk is also included. A test image 97 is also formed in order to detect the deviation in the main scanning direction x.

Although the test image 97 for searching for line deviation is also inclined by 45 ° with respect to the main scanning direction x, Bk, C, M, and Y line images are arranged in this order in the x direction. One group is formed near the x position of 76b and 76c, and there are three groups in total. Reading of these test images 9 7 stops the driving of the conveyor belt 57 when the test image 97 after the reading of the test image 96 has reached the x position of the sensor 76a to 76c, the sensor 76a to 76c main scanning direction This is performed by driving to x at a constant speed (24 in FIG. 10).

  The controller 17 calculates the shift amount in the main scanning direction x of the line leading end of other colors (line writing start end) with respect to Bk from the read result of the test image 97 and holds it as each color line leading end shift data. By subtracting from the difference in detection distance with respect to the reference value calculated from the read result of the test image 96, the subtracted value is held as each color page leading edge deviation data (25 in FIG. 10).

  The test image 94a for searching for the black pixel misalignment is also inclined by 45 ° with respect to the main scanning direction x, but is a Bk line image arranged in the x direction at a reference pitch, and the x direction of the conveyor belt 57 Is formed over the entire maximum imageable width. In reading these test images 94a, when the reading of the test image 97 is completed and the test image 94a reaches the x position of the sensors 76a to 76c, the driving of the conveyor belt 57 is stopped, as shown in FIG. Then, the sensors 76a to 76c are positioned outside the left end of all the test images 94a, and then the sensors 76a to 76c are driven by x to perform one main scan in the length section of the thick line arrow shown in FIG. Read (26).

  Next, the controller 17 calculates a deviation of the read line image at each pitch position from the x position (pixel position) of each reference pitch, and sends a group (Bk) to the x position (pixel position) of each reference pitch. The pixel position deviation data group) is stored in the memory (27), and is output to the output means (operation board 20 / printer 14 / PC) designated by the operator together with the temperature average value calculated in step 21 (28). ). Then, it waits for the sensor position designation input from the operator (29). The operator refers to the distribution of Bk pixel displacement data (for example, FIG. 22A), and sets sampling points for pixel displacement adjustment in the main scanning direction x to “fine”, “medium”, “ Specify either “Rough 1” or “Rough 2”. If not specified, the default is “medium”.

  Here, “fine” designates the x position (pixel position) of each of the reference pitches of the test image 94a for pixel position deviation search as a sampling point, and “medium” designates six for pixel position deviation search described later. The reference position of the test image 94d (FIG. 15C) is designated as a sampling point, and “Coarse 1” is three test images 94b for searching for pixel displacement described later (FIG. 15A). Is designated as the sampling point, and “rough 2” is designated as the sampling point for the three test images 94c (FIG. 15B) for searching for pixel displacement described later. It is. If there is a sensor position designation input, the default is “medium” if there is no input. In the sensor position selection table of the nonvolatile memory 19, the sensor position designation data column for the temperature region to which the detected temperature read this time belongs and for Bk Update writing is performed in (memory area) (29). The above is the content of “Bk position shift search” (22a).

  Subsequently, the controller 17 sequentially executes “c position shift search” (22b), “m position shift search” (22c), and “y position shift search” (22d). These contents are the same as the above-mentioned “Bk position shift search” (22a). However, the test image 94a for pixel position shift search is not Bk but m (magenta), c (cyan), and y (yellow), respectively, and the sensor position designation is specified in the sensor position selection table of the nonvolatile memory 19. Update writing is performed in the sensor position designation data column addressed to the current temperature range and m, c, and y.

  Four sets of start point deviation data (each color line leading edge deviation data, each color page leading edge deviation data) calculated in step 25 are obtained by executing “positional deviation search” (22a, 22b, 22c, 22d). The controller 17 checks and eliminates abnormal values using four sets of data, calculates an average value of normal values, and obtains the page leading instruction data and line leading instruction data for each color that minimizes the average value. The calculated and updated data is written to the temperature region to which the current temperature detection value of the start point table of the nonvolatile memory 19 belongs, and the page front end instruction data and the line front end instruction data are set in the switching timing data latch 65 (30). The above is the image shift search when “standard search” is instructed.

When the “simple search” (“simple fine”, “simple middle”, or “simple coarse”) mode is designated, the controller 17 performs the line shift search shown in FIG. Test images 96 and 97 are formed, and the pixel misalignment search test image 95a is inclined by 45 ° with respect to the main scanning direction x, similarly to the test image 97, but Bk, C, M , Y line images are alternately arranged in this order at the reference pitch in the x direction, and are formed over the entire maximum imageable width in the x direction of the conveyor belt 57 (23 e ). The contents of “read start point test bar” (24e) are the same as the above “read start point test bar” (24). The content of “Calculate & Update Start Point Deviation” (25e) is the same as “Calculate Start Point Deviation” (25) described above, but since the same “Calculate Start Point Deviation” is not executed thereafter, calculation is performed here. The page tip instruction data and line tip instruction data addressed to each color are updated and written to the temperature region to which the current temperature detection value of the start point table of the nonvolatile memory 19 belongs, and the page tip instruction data and line tip instruction data are switched. The data latch 65 is set (25e).

  Next, since the test image 95a for searching for the pixel position deviation is an image in which Bk, C, M, and Y line images are arranged in this order at the reference pitch in this order, “X of Bk, C, M, Y test bar” In “position reading” 26e, the test image 95a is read over the entire region in the x direction, and then the test bar position data is grouped by Bk, C, M, and Y (26e).

  Next, the controller 17 calculates a deviation from the x position (pixel position) of each reference pitch of each color line image for each color test bar position data group of Bk, C, M, Y (27e), and each color classification. And the temperature average value calculated in step 21 is output to the output means (operation board 20 / printer 14 / PC) designated by the operator (28). Then, it waits for an input of sensor position designation for each color from the operator (29e). The operator refers to four sets of distribution of each color pixel position deviation data (for example, (a) in FIG. 22), and sets sampling points for pixel position deviation adjustment in the main scanning direction x for each color. ”,“ Medium ”,“ Coarse 1 ”, or“ Coarse 2 ”. If not specified, the default is “medium” (29e).

  Refer to FIG. 9 again. When there is an instruction for “image shift adjustment”, the controller 17 executes “image shift adjustment” (9).

  FIG. 11 shows an outline of “image shift adjustment” (9). “Image shift adjustment” has six modes of “fine”, “medium”, “rough”, “simple fine”, “simple medium”, and “simple coarse”. Alternatively, one can be selected by input from the PC. The default is “simple density”, but this can also be changed by input from the operation board 20 or input from the PC. In “image shift adjustment” (9), the controller 17 first requests temperature data from the temperature detection circuits 83 and 84, calculates the average value of the temperature values represented by the temperature data output from the circuits 83 and 84, The data is converted into the temperature region data to which it belongs and the data is held (31).

  When the “dense” mode is selected, the controller 17 performs the line deviation search test image 96 shown in FIG. 14A and the test image 96 shown in FIG. 97 and a test image 94a for searching for Bk pixel position deviation are formed on the conveying belt 57 (34). Similarly to the “image misalignment search” (24 to 27 in FIG. 10), the test images 96 and 97 are read to calculate the color line leading edge misalignment data and the color page leading edge misalignment data. The update writing is made to the temperature region data obtained this time in the table, and the page leading instruction data and the line leading instruction data are set in the switching timing data latch 65 (35, 36). Next, the controller 17 reads the test image 94a (37). Next, the controller 17 calculates a deviation of the read line image at each pitch position from the x position (pixel position) of each reference pitch, and sends a group (Bk) to the x position (pixel position) of each reference pitch. The pixel position deviation data group) is stored in the memory (38). Next, the controller determines the total number of pixels on one line distributed in the M pitch in the entire main scanning direction (image forming area) based on the positional deviation data of the x position of each reference pitch, that is, the pixel positional deviation in the main scanning direction. A pixel shift in the main scanning direction of each of the M pixels is calculated using an interpolation method (interpolation method and extrapolation method), and adjustment data (the write clock generation circuit 21 is generated) that minimizes the pixel shift. One of the first to sixteenth pixel synchronization clock candidates) is generated, and the Bk adjustment data group addressed to the current temperature region data in the adjustment data table of the nonvolatile memory 19 is updated to the data group generated this time. Then, the data group generated this time is written into the selection data memory (67 in FIG. 5) of the phase synchronization circuit 22k (39). When the test image 94a is distributed at M pitches throughout the main scanning direction, no interpolation calculation is required, and adjustment data that minimizes each measurement calculation value (each pixel shift amount) held in the memory. Is the adjustment data of the pixel M pitch. The above is the content of “Bk positional deviation adjustment” (33a).

  Subsequently, the controller 17 sequentially executes “c positional deviation adjustment” (33b), “m positional deviation adjustment” (33c), and “y positional deviation adjustment” (33d). These contents are the same as the above-described “Bk positional deviation adjustment” (33a). However, the pixel misalignment search test image 94a is not Bk but m (magenta), c (cyan), and y (yellow), respectively.

  When the “medium” mode is selected, the controller 17 generates the Bk, c, m, and y color adjustment data groups and adjusts the nonvolatile memory 19 in the same manner as the “image shift adjustment” in the “fine” mode. The data group in the selected data memory (67 in FIG. 5) of the data table and the phase synchronization circuits 22k to 22y is updated to the one calculated this time. However, in the “medium” mode, instead of the test image 94a in which the test image is distributed over the entire area in the main scanning direction formed in the “dense” mode, a test image 94d having a six-point distribution shown in FIG. . Since four line images are formed at a short pitch in one place, the pixel shift in the main scanning direction of each of the four line images is obtained for one place, and the average value thereof is the pixel shift at the place (the center point). The detection value. In this way, when the respective pixel shift amounts at six locations (six sampling points) are obtained, they are used by the interpolation method (interpolation and extrapolation) at an M pitch in the entire main scanning direction (imaging region). The pixel shift in the main scanning direction of each distributed pixel number / M pixels on one line is calculated (40a to 40d).

  Reference is now made to FIG. When the “coarse” mode is selected, the controller 17 reads out the sensor position data addressed to the current temperature region data from the sensor selection position table (see step 29 in FIG. 10) in the nonvolatile memory 19. When the sensor position data is “coarse 1”, the sensor positions are set to Xa1, Xb1, and Xc1 shown in FIG. 15A, and 3 shown in FIG. When the location distribution 94b is formed and the sensor position data is “rough 2”, the sensor location is set to Xa2, Xb2, and Xc2 shown in FIG. A three-point distribution 94c shown in FIG. 15B is formed. In any case, since four line images are formed at a short pitch in one place, a pixel shift in the main scanning direction of each of the four line images is obtained for one place, and an average value thereof is calculated in the center of Point) pixel shift detection value. When the pixel shift amounts at three locations (three sampling points) are obtained in this manner, one line distributed at M pitches in the entire area in the main scanning direction (image forming region) is obtained by using them and using an interpolation method. The pixel shift in the main scanning direction of each of the upper total number of pixels / M is calculated (47a to 47d).

  When the “simple density” mode is selected, the controller 17 tests the line misalignment search test image 96 shown in FIG. 16A in the same manner as the above-described “image misalignment search” (23e in FIG. 10). And 97, and Bk, c, m, y test images are alternately distributed in this order, and a test image 95a for pixel misregistration search is formed on the conveying belt 57 (55). Similarly to the “image misalignment search” (24e to 27e in FIG. 10), the test images 96 and 97 are read to calculate each color line front end misalignment data and each color page front end misalignment data. The update data is written to the temperature region data obtained this time in the table, and the page end instruction data and the line end instruction data are set in the switching timing data latch 65 (56, 57). Next, the controller 17 reads the test image 95a (58). Next, the controller 17 groups the detected position data of each line image into those of Bk, c, m, and y, and for each group, the x position (each reference pitch) of the line image at each pitch position. Deviation from the pixel position is calculated and held in the memory as one group (pixel position deviation data group of each color) addressed to the x position (pixel position) of each reference pitch (59). Next, the controller distributes the color misregistration data group of each color at M pitches in the entire main scanning direction (image forming area) based on the positional misalignment data at the x position of the reference pitch, that is, the pixel misalignment in the main scanning direction. The pixel shift in the main scanning direction of each pixel of the total number of pixels / M on one line is calculated using an interpolation method, and adjustment data that minimizes the pixel shift (pixel synchronization generated by the write clock generation circuit 21) One of the first to sixteenth clocks) is generated, and each color adjustment data group addressed to the current temperature region data in the adjustment data table of the nonvolatile memory 19 is updated to the data group generated this time. Then, the data group generated this time is written into each selected data memory (67 in FIG. 5) of the phase synchronization circuits 22k to 22y (60).

  Reference is now made to FIG. When the “simple” mode is selected, the controller 17 generates Bk, c, m, and y color adjustment data groups to generate the non-volatile memory 19 in the same manner as the “image shift adjustment” in the “simple density” mode. The data group of the adjustment data table and the selection data memory (67 in FIG. 5) of the phase synchronization circuits 22k to 22y are updated to those calculated this time. However, in the “simple middle” mode, instead of the test image 95a in the entire main scanning direction formed in the “simple dense” mode, a test image 95d having a six-point distribution shown in FIG. 17C is formed. Since four line images are formed at a short pitch in one place, the pixel shift in the main scanning direction of each of the four line images is obtained for one place, and the average value thereof is the pixel shift at the place (the center point). The detection value. In this way, when the respective pixel shift amounts at six locations are obtained, they are used by the interpolation method, and the main scanning of the total number of pixels on one line / M pixels distributed in the M pitch in the entire main scanning direction. The pixel shift in the direction is calculated. Then, the data group generated this time is written into each selected data memory (67 in FIG. 5) of the phase synchronization circuits 22k to 22y (61 to 66).

  When the “simple rough” mode is selected, the controller 17 reads out the sensor position data addressed to the current temperature region data from the sensor selection position table (see step 29 in FIG. 10) of the nonvolatile memory 19. When the sensor position data is “rough 1”, the sensor position is set to Xa1, Xb1, and Xc1 shown in FIG. 17A, and the test position 95 shown in FIG. When the location distribution 95b is formed and the sensor position data is “rough 2”, the sensor location is set to Xa2, Xb2, and Xc2 shown in FIG. 17B and replaced with the test image 95d having the 3-location distribution. A three-location distribution 95c shown in FIG. 17B is formed. In any case, since four line images are formed at a short pitch in one place, the pixel shift in the main scanning direction of each of the four line images is obtained for one place, and the average value thereof is calculated as the pixel shift in the place. The detection value. In this way, when the respective pixel shift amounts at three locations are obtained, they are used by an interpolation method, and the total number of pixels on one line / M pixels distributed in M pitches throughout the main scanning direction. The pixel shift in the main scanning direction is calculated. Then, the data group generated this time is written into each selected data memory (67 in FIG. 5) of the phase synchronization circuits 22k to 22y (67 to 73).

  Refer to FIG. 9 again. When a print instruction (copy start, print start) is given from the operation board 20 or the personal computer PC to the process controller 17 via the system controller 1, the controller 17 reads the temperature detection data from the temperature reading circuits 83 and 84. An average value is calculated, and the average value is converted into temperature region data to which the average value belongs, and held (11). If it is the same as the temperature region data held in the register, an image is formed and discharged on one sheet. (11-12-16). As long as there is no temperature change (change in the temperature region to which the detected temperature belongs), the designated number of images are repeated (11, 12-16, 17).

  However, when there is a temperature change (change in the temperature region to which the detected temperature belongs), the temperature region data obtained this time is updated and stored in the register (13), and the temperature region data obtained this time in the start point table of the nonvolatile memory 19 and The page leading instruction data and the line leading instruction data addressed to each color are read out and set in each of the switching timing data latches (65) of the phase synchronization circuits 22k-22y (14). Then, the temperature region data obtained this time and the adjustment data group addressed to each color in the adjustment data table of the nonvolatile memory 19 are read out, and updated and written in the selection data memories (67) of the phase synchronization circuits 22k to 22y (15). . With this update process (14, 15), when there is a predetermined temperature change, a page given to the internal synchronization signal generation circuit 64 to a value determined to minimize color shift and pixel position shift at the new temperature. The leading edge instruction data and the line leading edge instruction data, and the adjustment data group for selecting the pixel synchronization clock candidate given to the selection gate 66 are updated.

  In the first embodiment described above, a test image is formed on the conveyor belt, and the position of the test image in the main scanning direction is detected by the sensors 76a to 76c. May be detected. In this case, detection may be performed at either the position before the sheet enters the fixing device 58 or the position downstream of the fixing device 58. In a color printer using an intermediate transfer belt, the above-described test image can be formed on the intermediate transfer belt, and the position of the test image in the main scanning direction can be detected by the sensors 76a to 76c.

1 is a front view of a full-color multifunctional copying machine that is an image forming apparatus according to an embodiment of the present invention. FIG. 2 is an enlarged longitudinal sectional view showing an outline of an image forming mechanism of the full-color printer 14 shown in FIG. 1. FIG. 3 is an enlarged plan view of the writing unit 30 shown in FIG. 2. It is a block diagram which shows the function structure of the image writing control part 16c in the image formation unit 16 shown in FIG. It is a block diagram which shows the outline | summary of a function structure of the write clock generation circuit 21 and the phase-synchronization circuits 22k-22y shown in FIG. FIG. 2 is a block diagram showing an outline of an image processing system of the copying machine shown in FIG. 1. (A) is an enlarged plan view of the conveyor belt 57 shown in FIG. 2, and (b) is an enlarged cross-sectional view. It is a block diagram which shows the functional outline | summary of a test bar reading circuit 79a-79c and other functional elements which process the detection signal of the sensors 76a-76c shown in FIG.7 (b). It is a flowchart which shows the outline | summary of the image processing control of the process controller 17 shown in FIG. 10 is a flowchart showing the contents of “image shift search” (7) shown in FIG. 9. 10 is a flowchart showing a part of the content of “image shift adjustment” (9) shown in FIG. 9; 10 is a flowchart showing another part of the content of “image shift adjustment” (9) shown in FIG. 9. 10 is a flowchart showing the remaining part of the content of “image shift adjustment” (9) shown in FIG. 9. (A) is an enlarged plan view of a part of the conveyor belt 57, and shows a test image formed on the conveyor belt 57 in "image shift search" (7) and "image shift adjustment" (9). (B) shows the positions of the test image 94a and the sensors 76a to 76c immediately before reading the test image 94a shown in (a). FIG. 15 is an enlarged plan view of a part of the conveyance belt 57, and shows three other forms of test images 94b, 94c, and 94d formed in place of the test image 94a shown in FIG. (A) is an enlarged plan view of a part of the conveyor belt 57, and shows another test image formed on the conveyor belt 57 in "image shift search" (7) and "image shift adjustment" (9). Show. (B) shows the positions of the test image 95a and the sensors 76a to 76c immediately before the test image 95a shown in (a) is read. FIG. 17 is an enlarged plan view of a part of the conveyance belt 57, and shows other three forms of test images 95b, 95c, and 95d formed in place of the test image 95a shown in FIG. 8A is a time chart showing the input voltage of the A / D converter 90 of the test bar reading circuit 79a shown in FIG. 8, and FIG. 8B is a time chart showing a voltage range read by the controller 17 after digital conversion by the A / D converter 90. It is. 5 is a time chart showing pixel synchronization clocks CLKo and CLKa given to the laser drive circuits 23k to 23y shown in FIG. 4 and image forming position shifts of test bars formed in synchronization therewith. It is a time chart which shows transition by the temperature change of the image formation position shift amount of a test bar with time. (A) is a graph showing the image forming position deviation amount in the main scanning direction at each position in the main scanning direction on one main scanning line, and (b) is a graph showing three positions (Xa1d, Xb1d, Xc1d). The amount of deviation after correction based on the deviation detection value is shown, and (c) further adds one point (Xa2d) and corrects based on the deviation detection value of four points (Xa1d, Xa2d, Xb1d, Xc1d). Indicates the amount of deviation. (A) is a graph showing the image forming position deviation amount in the main scanning direction at each position in the main scanning direction on one main scanning line, and (b) is a graph showing six positions (Xa1d, Xa2d, Xb1d, Xb2d). , Xc1d, Xc2d) shows the amount of deviation after correction based on the detected deviation value.

30: Write unit 31y, 31m, 31c, 31bk: Laser diode unit (LD unit)
32y, 32m, 32c, 32bk: cylinder lens 33bk, 33y: reflection mirror 34: polygon mirror 35bkc, 35ym: fθ lens 36y, 36m, 36c, 36bk: first mirror 37bkc, 37ym: cylinder mirror 38bkc, 38ym: sensor 48: First tray 49: Second tray 50: Third tray 51: First paper feeder 52: Second paper feeder 53: Third paper feeder 54: Vertical transport unit 56: Photoconductor 57: Transport belt 58: Fixing Unit 59: paper discharge unit 60: branch claw 26: transport motor 55: developing device 100: finisher 101: switching plate 103: paper discharge roller 104: paper discharge tray 105: transport roller 106: stapler 107: transport roller 108: staple table 109: Jogger 110: Paper discharge tray 111: Double-sided paper feed Knitting 112: reversing unit

Claims (18)

In an image forming apparatus that switches a recording signal addressed to a pixel in synchronization with a pixel synchronization clock that defines a pixel section on a line in the main scanning direction and performs pixel recording on the line in the main scanning direction by the recording signal.
Image detecting means for detecting recording pixel position shifts in the main scanning direction at a plurality of locations on the line;
Distributed at a pitch of a plurality of pixels smaller than the number of pixels between the plurality of locations on the line in the main scanning direction, calculated based on the displacement of the recording pixels in the main scanning direction at the plurality of locations detected using the image detecting means to shift the recording pixel position in the main scanning direction at a plurality of points, of for reducing respectively, adjustment data storage means for storing the location addressed pixel synchronizing clock adjustment data of the plurality of points each of the main scanning direction;
The image recording position on the line by the main scanning, the each time pitch changes, the adjustment data read address of the memory means of the address is switched to the position addressed was the change pixel synchronizing clock adjustment data reading reading means ;and,
Multi-clock generation means for generating a plurality of pixel synchronization clock candidates having the same period but shifted in phase, and one pixel synchronization clock corresponding to the pixel synchronization clock adjustment data read by the reading means is selectively output. Adjustment means including selection means ;
An image forming apparatus comprising:   The image forming apparatus according to claim 1, further comprising a drive unit that supports the image detection unit and drives the image detection unit in the main scanning direction.   The image forming apparatus according to claim 2, further comprising a position control unit that controls the driving unit to drive the image detection unit to a set position on a line in the main scanning direction.   After the test image, which is intermittently distributed in the main scanning direction for detecting misalignment in the first set of locations, is read by the image detecting device, the image detecting device is driven to the second set of locations, The test image that is intermittently distributed in the main scanning direction for detecting the positional deviation at the location is read by the image detecting means, the position of the read test image in the main scanning direction is detected, and the reference position of the test image in the main scanning direction is detected. The adjustment data generation means which calculates the shift | offset | difference of this, produces | generates the pixel synchronous clock adjustment data which minimizes a deviation | shift, and stores it in the said adjustment data storage means; Image forming apparatus. In an image forming apparatus that switches a recording signal addressed to a pixel in synchronization with a pixel synchronization clock that defines a pixel section on a line in the main scanning direction and performs pixel recording on the line in the main scanning direction by the recording signal.
Image detecting means for detecting a recording pixel position shift in the main scanning direction on the line;
Driving means for supporting the image detecting means and driving in the main scanning direction;
Was calculated on the basis of the main scanning direction of the recording pixel offset of the plurality of points on said image detecting means is driven in the main scanning direction in the main scanning direction detected by using the image detection means line by said drive means, the main Main scanning at each of the plurality of points for reducing each of a plurality of recording pixel positional deviations in the main scanning direction distributed at a pitch of a plurality of pixels smaller than the number of pixels between the plurality of points on the line in the scanning direction. Adjustment data storage means for storing pixel synchronous clock adjustment data addressed to the position in the direction;
The image recording position on the line by the main scanning, the each time pitch changes, the adjustment data read address of the memory means of the address is switched to the position addressed was the change pixel synchronizing clock adjustment data reading reading means ;and,
Multi-clock generation means for generating a plurality of pixel synchronization clock candidates having the same period but shifted in phase, and one pixel synchronization clock corresponding to the pixel synchronization clock adjustment data read by the reading means is selectively output. Adjustment means including selection means ;
An image forming apparatus comprising: A test image that is intermittently distributed in the main scanning direction for detecting misalignment of the detected portion is read by the image detecting means, a position of the test image in the main scanning direction is detected, and a reference position in the main scanning direction of the test image is detected. according to further any one of claims 2 to 5 comprising a; deviation is calculated, and generates the pixel synchronizing clock adjustment data to minimize the deviation, adjustment data generating means for storing the adjustment data storage means Image forming apparatus. Reads detection signals generated by the image detecting means when the driving means drives the image detecting means in the main scanning direction for reading test images intermittently distributed in the main scanning direction for detecting displacement. Detects the position of the test image in the main scanning direction based on the level change of the detection signal, calculates the deviation of the test image from the reference position in the main scanning direction, and generates pixel synchronization clock adjustment data that minimizes the deviation The image forming apparatus according to claim 2 , further comprising an adjustment data generation unit that is stored in the adjustment data storage unit. In an image forming apparatus that switches a recording signal addressed to a pixel in synchronization with a pixel synchronization clock that defines a pixel section on a line in the main scanning direction and performs pixel recording on the line in the main scanning direction by the recording signal.
Test image forming means for forming each test image on each of the plurality of reference positions in the main scanning direction on the test surface;
Image position detecting means for detecting the position of each test image formed on the test surface in the main scanning direction;
Adjustment data storage means;
A plurality of points distributed at a pitch of a plurality of pixels smaller than the number of pixels between the reference positions on the line in the main scanning direction, calculated based on a deviation of each test image position detected using the image detection unit with respect to each reference position Adjustment data generation for generating pixel synchronous clock adjustment data addressed to the positions in the main scanning direction of the plurality of points and storing them in the adjustment data storage means for reducing each of the recording pixel position shifts in the main scanning direction means;
The image recording position on the line by the main scanning, the each time pitch changes, the adjustment data read address of the memory means of the address is switched to the position addressed was the change pixel synchronizing clock adjustment data reading reading means ;and,
Multi-clock generation means for generating a plurality of pixel synchronization clock candidates having the same period but shifted in phase, and one pixel synchronization clock corresponding to the pixel synchronization clock adjustment data read by the reading means is selectively output. Adjustment means including selection means ;
An image forming apparatus comprising: The image forming apparatus further includes a temperature detection unit; the adjustment data storage unit holds a pixel synchronous clock adjustment data group addressed to each of a plurality of temperature sections, and the reading unit includes a temperature to which the temperature detected by the temperature detection unit belongs. the data of the pixel synchronizing clock adjustment data group destined for division is read from the adjustment data storage means; image forming apparatus according to any one of claims 1 to 8. When the temperature detected by the temperature detecting means has changed from the previous temperature, the reading means reads the pixel synchronous clock adjustment data from the adjustment data storage means to the temperature section to which the detected temperature belongs. The image forming apparatus according to claim 9 , wherein the previous temperature is updated to the detected temperature by switching to another data group . The image forming apparatus further includes a temperature detection means and a detection location storage means for storing a position shift detection location addressed to each of the temperature sections; the position control means is assigned to a temperature section to which the temperature detected by the temperature detection means belongs. The image forming apparatus according to any one of claims 1 to 10, wherein an addressed detection location is read from the detection location storage means, and the image detection means is driven to the detection location. The image forming apparatus forms an electrostatic latent image on the photosensitive member by switching a laser recording pixel-synchronizing signal synchronized with the pixel synchronization clock during the main scanning direction laser scanning with respect to the photosensitive member. A laser printer comprising frequency adjusting means for adjusting a frequency of an original clock so that the number of pixels in one line of laser scanning is set as a set value; 12. A first frequency dividing unit that divides and outputs a plurality of frequency- divided signals having the same cycle but relatively shifted in phase by an integer cycle of the original clock; The image forming apparatus described. The pixel synchronization clock adjustment data of the adjustment data storage means is for each division obtained by dividing the number of pixels in one line of laser scanning by two or more M pixel pitches; the reading means is the selection means Includes a second frequency dividing unit that divides the pixel synchronization clock output by 1 / M and a count unit that counts the clock divided by 1 / M, and the pixel synchronization associated with the count data of the counting unit reads clock adjustment data from the adjustment data storage means; image forming apparatus according to any one of claims 1 to 12. The image forming apparatus is a color printer that includes a plurality of image forming units that form images of a plurality of colors and forms a color image on a transfer sheet by superimposing a plurality of color images; for each of a plurality of colors, to form the test image on the test surface and stores this in the product and the adjustment data storage means of the pixel synchronizing clock adjustment data; according to claim 4, 6, 7 or 8 Image forming apparatus. The image forming apparatus is a color printer that includes a plurality of image forming units that form images of a plurality of colors and forms a color image on a transfer sheet by superimposing a plurality of color images; A plurality of test images of a plurality of colors are formed side by side in the main scanning direction on the test surface, each color test image on the same test surface is read, and the pixel synchronous clock adjustment data is generated for each color and stored in the adjustment data storage means The image forming apparatus according to claim 4, 6, 7, or 8 . The image forming apparatus according to claim 14 or 15;
Imaging means for generating color component image data of an image having an imaging element and projected thereon; and
An image data processing device for converting color component image data generated by the imaging means into image data for color image formation of the color image forming device and outputting the image data to the color image forming device;
A color image forming apparatus comprising: The image forming apparatus according to claim 14 or 15, and
An image data processing device that converts document information instructed by an external device to print image data that is compatible with the image forming device and outputs the data to the image forming device;
A color image forming apparatus comprising: The image forming apparatus according to claim 14 or 15;
Imaging means for generating color component image data of an image having an imaging element and projected thereon; and
The color component image data generated by the imaging unit is converted into image data for color image formation of the color image forming apparatus and output to the color image forming apparatus. An image data processing device that converts the recorded image data into a suitable recording image data and outputs it to the image forming device;
A color image forming apparatus comprising:

Images