JP2009066907A - Method of controlling line head and image forming device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of controlling a line head in which image quality is improved by correcting the displacement of exposure position, and an image forming device using the method. <P>SOLUTION: The amount of displacement of the exposure position of a photosensitive member in each photosensitive element line in the rotating direction is stored in a resistor (○1). A pattern for detecting the curved/skew deviation amount is printed (○2). In printing, the conversion of sequence of pixel data in a lens and a processing for correcting the displacement of the exposure position in each light emitting element line in the auxiliary scanning direction are performed. The printed pattern for detecting the curved/skew deviation amount is read by an optical sensor, and the curved amount and the skew deviation amount are measured in unit of μm (○3). From the results of the measurement, curved displacement correction information and skew correction information are calculated (○4). The calculated curved displacement correction information and the skew correction information are stored in an EEPROM (○5). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for controlling a line head that corrects exposure position deviation and the like to suppress image quality deterioration and an image forming apparatus using the same.

  As an exposure light source for an image forming apparatus, a configuration in which a line head using LEDs is installed is known. Patent Document 1 proposes a method of correcting the skew deviation caused by the accuracy of the line head body attachment in units of blocks corresponding to the skew deviation amount. In the present invention, the image memory is divided into a plurality of storage areas along the axial direction (main scanning direction) of the photoconductor based on the skew deviation amount. That is, it is divided into block units. Next, the read address of each divided storage area is converted in accordance with the skew deviation amount to correct the skew deviation. Thus, skew shift correction is realized with a small memory capacity and a simple circuit configuration.

JP 2003-285473 A

  In a micro lens array (MLA) line head using a micro lens having a negative optical magnification as an imaging lens array, a plurality of rows are arranged in the rotation direction (sub-scanning direction) of the photoconductor with respect to a single lens. The light emitting element rows are arranged. For this reason, an exposure position shift in which a latent image is formed at a position different in the rotation direction occurs in the photosensitive member. The conventional skew correction method in units of blocks as described in Patent Document 1 does not consider such exposure position deviation.

  In addition, the line head may be bent due to manufacturing accuracy. In such a case, the latent image formed on the photosensitive member is deviated in curvature and the image quality is deteriorated. Patent Document 1 does not consider the suppression of image quality degradation due to such a curvature deviation. For this reason, the patent document 1 has a problem that it cannot cope with image quality deterioration of the MLA line head.

  Further, in Patent Document 1, when acquiring the skew correction information of the line head, a skew displacement amount detection pattern is printed, and the print result is measured by an optical sensor or the like, thereby determining the skew displacement amount. Detected. However, since the MLA line head has an exposure position shift for each light emitting element row as described above, the skew shift amount detection pattern itself cannot be printed normally when Patent Document 1 is applied. For this reason, there is a problem that accurate skew correction information cannot be acquired.

  The present invention has been made in view of the above-described problems of the prior art, and its object is to provide a curvature deviation caused by the manufacturing accuracy of the line head, a skew deviation caused by the body mounting accuracy, and an exposure position deviation. It is an object of the present invention to provide a line head control method and an image forming apparatus using the same.

The line head control method of the present invention that achieves the above object comprises a substrate, a light emitter array in which a plurality of light emitting elements are arranged on the substrate along an axial direction of a photoreceptor, and a light emitting element group row is formed; An image forming lens array provided corresponding to the light emitter array, the light emitter array and the image forming lens array being arranged in a plurality of rows with respect to the rotation direction of the photoconductor, Each has a line head that forms a latent image at a different position,
The light emitting element is divided into a plurality along the axial direction of the photoconductor to form a block,
Perform rearrangement processing of pixel data corresponding to the light emitting elements in the block, and transmission delay processing of the pixel data,
A method of controlling a line head, comprising correcting a curvature deviation caused by manufacturing accuracy of the line head, a skew deviation caused by accuracy of mounting of the main body, and an exposure position deviation of the photosensitive member.

  In the line head control method of the present invention, the block unit is a plurality of light emitting elements corresponding to one lens of the imaging lens array.

  In the line head control method of the present invention, the pixel data rearrangement process is an emission order rearrangement process corresponding to a lens having a negative optical magnification of the imaging lens array.

  In the line head control method of the invention, the pixel data transmission delay process is a process of correcting an exposure position deviation for forming a latent image at a different position for each row with respect to the photoconductor. And

  Further, the line head control method of the present invention is different for each row with respect to the photoconductor, the curve correction information for correcting the curve shift, the skew correction information for correcting the skew shift, and the photoconductor. And a light emitting element row correction information for correcting an exposure position shift of the light emitting element row of the line head that forms a latent image at the position.

  In the line head control method of the present invention, before performing the bending deviation amount measurement for obtaining the curvature correction information and the skew deviation amount measurement for obtaining the skew correction information, the optical head is controlled. The rearrangement process of the light emission order corresponding to a lens with a negative magnification is performed.

  In the line head control method of the present invention, the light emission may be performed before the curvature deviation amount measurement for obtaining the curvature correction information and the skew deviation amount measurement for obtaining the skew correction information. The exposure position shift of the light emitting element row is corrected according to the element row correction information.

  The image forming apparatus according to the present invention includes an image forming station in which image forming units including a charging unit, a line head controlled by any of the above methods, a developing unit, and a transfer unit are arranged around an image carrier. At least two or more are provided, and the transfer medium passes through each of the image forming stations so that image formation is performed by a tandem method.

  The present invention will be described below with reference to the drawings. FIG. 9 is an explanatory diagram showing an embodiment of the present invention. FIG. 9A is a plan view partially showing the line head in a state in which the light emitting element group 6 is viewed through the imaging lens 4, and FIG. 9B is a relationship between the single imaging lens 4 and the light emitting element group 6. FIG. As shown in FIG. 9A, a plurality of light emitting element groups are arranged in correspondence with each imaging lens in the axial direction (main scanning direction) of the photosensitive member.

  As described above, the light emitting elements are divided into block units corresponding to the respective imaging lenses along the axial direction of the photosensitive member. In addition, a plurality of imaging lenses 4 are provided in the axial direction and the rotation direction of the photoconductor to constitute an imaging lens array. The light emitting element group 6 is formed on a substrate, and constitutes a light emitting element array as a whole.

  In the embodiment of the present invention, such a state in which a plurality of light emitting element groups are arranged in the axial direction of the photosensitive member is defined as a “light emitting element group row”. In FIG. 9A, a plurality of light emitting element group rows A, B, and C are arranged in the rotation direction of the photosensitive member. Each light emitting element group row AC forms a light emitter array as described above. In the light emitting element groups adjacent to each other in the axial direction of the photosensitive member in each of the light emitting element group rows A to C, the lengths R, S, and T between the center positions are set equal. In addition, in the light emitting element groups of the respective light emitting element group rows A to C adjacent in the rotation direction of the photosensitive member, the lengths r, s, and t between the center positions are set to be equal.

  In FIG. 9B, the light emitting element group 6 is provided with a light emitting element row 7a in which a plurality of light emitting elements are arranged in the axial direction of the photoreceptor. A plurality of the light emitting element rows are arranged in the rotation direction of the photosensitive member, and in the example of FIG. 9B, light emitting element rows 7a, 7b, and 7c are provided. As described above, FIGS. 9A and 9B describe that, for example, in the light emitting element group row A, three light emitting element rows 7a, 7b, and 7c are provided. In addition, the imaging lenses are also arranged in three rows in the rotation direction of the photosensitive member.

  FIGS. 10 and 11 are explanatory diagrams of an example in which the exposure position shift occurs in the photosensitive member in the line head in which the imaging lens and the light emitting element group are associated as shown in FIG. In FIG. 10, single coupled lenses 4, 5, and 8 are arranged at the head positions of the light emitting element group rows A to C, respectively. The pitch between coupled lens rows is Da and Db.

  As the coupling lens, a micro lens (ML) having a negative optical magnification is used, and a group of each ML forms a micro lens array (MLA). In such an MLA, an exposure position shift occurs due to individual differences in the pitch between MLA lens rows and the diameter of the photoconductor. When such an exposure position shift occurs, a latent image as shown in FIG. 11A is formed on the photoreceptor.

  In FIG. 11A, reference numerals 6a, 6b, and 6c denote patterns of latent images formed on the photoconductor when the MLA exposure position deviation is not corrected. Ta represents the MLA inter-lens exposure position shift, and Tb represents the MLA in-lens exposure position shift. Here, the distance between the lens rows represents a relationship between the lenses when a plurality of imaging lenses are arranged in a direction orthogonal to the axial direction of the photosensitive member. The latent image pattern 6a includes latent image rows k to n. The latent image pattern 6b includes latent image rows p to r, and the latent image pattern 6c includes latent image rows s to u.

  FIG. 11B is an explanatory diagram showing a latent image when the exposure position deviation of the MLA is corrected. At this time, the latent image 16 is formed on the photosensitive member like 17a to 17f by the output light transmitted through each ML. That is, the latent image is formed in one linear shape in the axial direction (main scanning direction) of the photosensitive member. For this reason, deterioration of image quality can be suppressed. In this correction, for example, the following processing is performed if the moving direction of the photosensitive member is Y. In the example of the latent image pattern 6a in FIG. 11A, the in-lens exposure position deviation correction is performed with the latent image row k as a reference. That is, the latent image sequence m is formed at a timing delayed by one row from the latent image sequence k. Further, the latent image row n is formed at a timing delayed by two rows from the latent image row k.

  Similarly, the latent image patterns 6b and 6c are also subjected to exposure position shift correction by delaying the latent image row by row. In the lens row exposure position correction, the latent image pattern 6b is delayed by one timing in the Y direction with reference to the latent image pattern 6a, and the latent image pattern 6c is delayed by two timings in the Y direction. Therefore, the actual exposure position deviation correction is formed by delaying the timing in the Y direction sequentially for each line image row m to u with reference to the latent image row k of the latent image pattern 6a.

In the embodiment of the present invention, the exposure position shift of the MLA is corrected by controlling the light emitting element in the block unit. Also,
It corrects the curvature deviation caused by the manufacturing accuracy of the line head and the skew deviation caused by the accuracy of mounting the main body together to prevent image quality deterioration. Hereinafter, this embodiment will be described.

  In the present invention, a microlens having a negative optical magnification is used. For this reason, it is necessary to rearrange the data, unlike when using a lens with a positive optical magnification. This point will be described first. FIG. 3 is an explanatory diagram showing the relationship between the arrangement of the light emitting elements and the latent image formed on the photoconductor when a lens having a positive optical magnification is used. In FIG. 3, 2 is a light emitting element in which ◯ 1 to ◯ 60 are arranged (hereinafter, a circled number is expressed as ◯ 1 for reasons of conversion). 4a is a lens, and 6 is a latent image. In this example, the latent image forming dots ◯ 1 to ６０60 formed on the photoconductor via the lens 4a correspond to the light emitting elements ◯ 1 to ６０60. Y is the rotation direction of the photosensitive member.

  FIG. 4 is an explanatory diagram of an example in which a microlens having a negative optical magnification is used. In FIG. 4, the light-emitting elements 2 are arranged in the order of ○ 1 to ○ 60 as in FIG. 3. The microlens 4 having a negative optical magnification irradiates the photoconductor by inverting the output light of the light emitting element 2 in the axial direction of the photoconductor and the rotating direction of the photoconductor. For this reason, the imaging dots ○ 1 to ○ 60 of the latent image 6 formed on the photosensitive member are reversed from the arrangement of the light emitting elements 2 in the axial direction of the photosensitive member and in the rotation direction of the photosensitive member. Become. Therefore, when forming a latent image on the photoconductor as in FIG. 3, it is necessary to rearrange the data so as to be reversed in the axial direction of the photoconductor and the rotation direction of the photoconductor.

  FIG. 1 is a block diagram showing a procedure for obtaining each correction information. In FIG. 1, the exposure position deviation amount (in line units) in the rotation direction (sub-scanning direction) of the photosensitive body of each light emitting element row is preliminarily calculated from the light emitting element arrangement (design value) of the MLA and the line head. It is stored in 20 registers (◯ 1). In this embodiment, the exposure position deviation between the light emitting element rows in the light emitting element group is 2 lines, and the exposure position deviation between the light emitting element groups is 160 lines.

  A pattern for detecting the amount of bending / skew deviation is printed (○ 2). When printing, exposure position deviation correction processing in the sub-scanning direction of each light emitting element row is performed according to the light emitting element row correction information stored in the register of the head controller (e). The exposure position deviation correction process in the sub-scanning direction will be described later. Further, when the lens has a negative optical magnification, the order of arrangement of the light emitting elements and the exposure position are different as shown in FIG. 4, and therefore the order of pixel data is converted in the lens (◯ 2, d).

  The printed curved / skew deviation detection pattern is read by an optical sensor or the like, and the curvature deviation and the skew deviation are measured in μm units (○ 3). Curve correction information and skew correction information are calculated from the measurement result (◯ 4). At this time, the bending deviation amount and the skew deviation amount are converted from μm units to line units. The calculated curvature correction information and skew correction information are stored in the EEPROM mounted on the line head 10 (◯ 5). This process corresponds to a process of writing the curvature correction information and the skew correction information in the EEPROM.

  As described above, in the embodiment of the present invention, the exposure position deviation of the light emitting element row is corrected according to the light emitting element row correction information before printing the curve / skew deviation amount detection pattern of the line head, and the optical magnification is increased. The order of pixel data corresponding to the negative lens is converted. For this reason, there is an advantage that the pattern for detecting the amount of bending / skew deviation of the line head can be printed accurately. In addition, after accurately printing the line head curve / skew deviation detection pattern, the curve deviation measurement for obtaining the curve correction information of the line head and the skew for obtaining the skew correction information are obtained. The amount of deviation is measured. For this reason, it is possible to accurately correct curvature / skew deviation.

  FIG. 2 is a block diagram of the control unit in the embodiment of the present invention. In FIG. 2, a head controller 20, a print controller 21, and a mechanical controller 22 are provided as control means for the line head 10. The print controller 21 includes an image processing unit 21a, and the head controller 20 includes an EEPROM communication control unit 23, a video I / F unit 26, a sub-scanning direction exposure position deviation correction unit 27, and a line head. A control signal generation unit 28, a request signal generation unit 29, a register 30, a write address generation unit 31, and an in-lens data order conversion unit 32 are provided. The sub-scanning direction exposure position deviation correction unit 27 includes an SRAM, and the in-lens data order conversion unit 32 includes a buffer 1 and a buffer 2. Further, the register 30 stores light emitting element row correction information, curvature correction information, and skew correction information.

  When the printer is turned on, the EEPROM communication control unit 23 reads the curvature correction information and the skew correction information from the EEPROM 25 mounted on the line head 10 and stores them in the register 30 of the head controller 20 (◯ 1 ). Here, the curvature correction information and the skew correction information are stored in advance in the EEPROM when the printer is shipped.

  When printing is started, the mechanical controller 22 detects the end of the recording paper, and transmits a Vsync signal to the request signal generation unit 29 of the head controller 20 (（2). The request signal generation unit 29 generates a Vreq signal (video data request signal) and an Hreq signal (line data request signal), and transmits them to the print controller 21 via the video I / F unit 26 (◯ 3). The Hreq signal is sent to the write address generation unit 31, the sub-scanning direction exposure position deviation correction unit 27, and the head control signal generation unit 28 to synchronize the modules.

  The print controller 21 transmits the processed image data to the video I / F unit 26 of the head controller 20 by using the received Vreq signal and Hreq signal as a trigger (◯ 4). At this time, in order to reduce the wiring cost and facilitate the wiring, it is desirable to convert parallel image data into serial data (parallel-to-serial conversion) and transmit the data through high-speed serial communication.

  The video I / F unit 26 converts the image data from serial to parallel and transmits it to the in-lens data order conversion unit 32 (○ 5). The in-lens data order conversion unit 32 rearranges the image data in the light emission order corresponding to the negative optical magnification of the microlens and transmits it to the sub-scanning direction exposure position deviation correction unit 27 (（6). In the present embodiment, the in-lens data order conversion unit 32 performs in-lens data order conversion using two line buffers. One line buffer writes the order-converted image data, and the other line buffer reads the order-converted image data, so that the processing speed difference between the in-lens data order conversion unit 32 and the sub-scanning direction exposure position deviation correction unit 27 is reduced. Is absorbed.

  The sub-scanning direction exposure position deviation correction unit 27 corrects various sub-scanning direction deviations by writing the sequence-converted image data into the SRAM in accordance with the write address generated by the write address generation unit 31 (○ 7). . The write address generation unit 31 generates a write address based on the light emitting element row correction information, the curvature correction information, and the skew correction information stored in the register 30 (the write address generation method will be described in detail later). In this embodiment, the write address is generated based on the correction information and the exposure position deviation in the sub-scanning direction is corrected. However, the read address is generated based on the correction information and the deviation in the sub-scanning direction is corrected. You may do it.

  The corrected image data stored in the SRAM of the sub-scanning direction exposure position deviation correction unit 27 is read and transmitted to the line head 10 (○ 8). At this time, the read address monotonically increases as 0, 1, 2,. At the same time, the head control signal generator 28 generates various head control signals (clock, start signal, reset signal, etc.) and transmits them to the line head 10 (○ 8).

  FIG. 5 is an explanatory diagram showing an image data writing image 32 to the SRAM provided in the sub-scanning direction exposure position deviation correction unit 27 described in FIG. In this example, the light emitting element arrangement is similar to that of FIG. 10, the light emitting element group is three groups (A, B, C), the light emitting element rows in the group are three rows (1, 2, 3), and the light emitting element rows are between. It is assumed that the exposure position deviation amount is 2 lines in the rotation direction of the photoconductor, and the exposure position deviation amount between the light emitting element group rows is 160 lines in the rotation direction of the photoconductor.

  In addition, nine light emitting elements are arranged in one microlens, 15 light emitting elements are divided into one block that divides the light emitting elements arranged in the axial direction of the photosensitive member, and the curve / skew deviation amount of block No0 is two lines. The amount of curve / skew deviation of block No. 1 is one line. In FIG. 9A, the light emitting element blocks are arranged in correspondence with the respective imaging lenses. However, in the example of FIG. 5, the light emitting element blocks are not associated with the imaging lenses. . In FIG. 5, only two blocks No. 0 and No. 1 are displayed, but there is a block number of “total number of dots in the axial direction of the photosensitive body of the line head / 15”.

  In FIG. 5, 32 line addresses of line addresses 0 to 31 are displayed. The line address number corresponds to the array number from the left end side of the light emitting elements arrayed in the photosensitive body axis direction of the line head. As described above, since nine light emitting elements are arranged in one microlens, the line number is divided for each nine line address numbers to correspond to lens numbers 0 to 3. In addition, since 15 light emitting elements are arranged in one block, a delimiter line is written in the portions 14 and 31 of the line address. In the example of the light emitting element group A, when the block number is 0, pixel data D7, D4, and D1 are written in BANK2. In addition, pixel data D8, D5, and D2 are written in BANK4. Further, pixel data D9, D6, and D3 are written in BANK6.

  When one latent image is formed in the axial direction of the photoreceptor, the pixel data in the light emitting element group A is originally D1, D2, D3, D4, D5, D6, D7, D8 when the block number is 0. Are exposed in the order of D9. However, since a microlens having a negative optical magnification is used, it is necessary to reverse the pixel data in the axial direction of the photosensitive member and perform the rearrangement for writing to the line address. is there. FIG. 6 is an explanatory diagram of an image 32a for performing rearrangement for writing such pixel data into the storage means. In FIG. 6A, pixel data is written in BANK0, BANK2, and BANK4 in the order of D1 to D9 in the axial direction of the photosensitive member. FIG. 6B shows the pixel data in the light emitting element group A when viewed in the axial direction of the photoconductor, by inverting FIG. 6A to D7, D8, D9, D4, D5, D6, D1, Pixel data is written in the order of D2 and D3. The pixel data of the light emitting element group B and the light emitting element group C is also rearranged in the same manner as inverted in the axial direction of the photosensitive member.

  Similarly, in the rotation direction of the photosensitive member, it is necessary to perform the rearrangement in which the pixel data is inverted and written to the line address. FIG. 7 is an explanatory diagram of an image 32b in which such pixel data is rearranged to be written with spots in the rotation direction of the photosensitive member. FIG. 7 (a) corresponds to FIG. 6 (b). The pixel data D7, D8, D9, D4, D5, D6, D1, D2, and D3 in the light emitting element group A inverted in the axial direction of the photosensitive member are shown in FIG. Invert in the direction of rotation. Accordingly, when viewed in the rotating direction of the photosensitive member, the pixel data in the light emitting element group A is written in the pixel data corresponding to the order of D9, D8, D7, D6, D5, D4, D3, D2, D1. Has been done. FIG. 7B corresponds to an arrangement of pixel data of the light emitting element group A of FIG. Similar rearrangement is performed on the pixel data of the light emitting element group B and the light emitting element group C. As described above, in the example of FIG. 5, the pixel data is rearranged in the axial direction of the photoconductor and the rotation direction of the photoconductor.

  Here, in each light emitting element group, three light emitting element rows are arranged, and the exposure position shift amount of each light emitting element row is two lines. For this reason, for example, in the light emitting element group A, pixel data is written in the address of BANK4 which is delayed by two lines in the rotation direction of the photosensitive member with respect to the address of BANK2. In addition, image data is written in the address of BANK 6 which is delayed by two lines in the rotation direction of the photosensitive member with respect to the address of BANK 4. As described above, the pixel data is written in the light emitting element row of each light emitting element group at an address delayed by two lines in the rotation direction of the photosensitive member.

  As described above, the bending / skew deviation amount of the block No0 is 2 lines, and the bending / skew deviation amount of the block No1 is 1 line. For this reason, as for the pixel data corresponding to the light emitting elements arranged in the block No 0, for example, the image data is written to the BANK 2 address of the light emitting element group A with a delay of two lines from the head BANK 0. Further, pixel data is written to the BANK 162 address of the light emitting element group B with a delay of two lines from the head BANK 160.

  Next, pixel data is written into the BANK 321 address of the light emitting element group C corresponding to the block No 1 with a delay of one line from the head BANK 320. Further, pixel data is written to the BANK 161 address of the light emitting element group B with a delay of one line from the head BANK 160. As described above, the pixel data corresponding to the light emitting element group B includes a delay of 2 lines and a delay of 1 line in a block correspondence.

  FIG. 8 is a block diagram illustrating an example in which a write address is generated in the write address generation unit 31 described in FIG. The line counter 71 counts 0 to the total number of dots formed in the axial direction of the photoreceptor. The line counter 71 counts up the line address by using the clock signal (Clk) as a trigger, and generates the write address 1. The write address is formed in units of pixel data. The line address is reset using the Hreq signal as a trigger. That is, initialization is performed.

  The BANK counter 72 counts up the BANK address using the Hreq signal as a trigger, and resets (initializes) the BANK address using the Vreq signal as a trigger. The BANK counter 72 counts BANK from 0 to 479 in association with FIG.

  When the value of the line address reaches the number of dots of one block (15 dots), the curve / skew correction information management unit 73 reads the curve / skew correction information (BANK unit) of the line head corresponding to each block. The light emitting element row correction information management unit 74 reads light emitting element row correction information (BANK unit) corresponding to each dot from the value of the line address. A write address 2 is generated by adding the BANK address, the read curvature / skew correction information, and the light emitting element row correction information. The write address 1 and the write address 2 are combined to generate the SRAM write address.

  In the embodiment of the present invention, a tandem color printer that exposes four photoconductors with four line heads, simultaneously forms four color images, and transfers them onto one endless intermediate transfer belt (intermediate transfer medium). The target is a line head used in (image forming apparatus). FIG. 12 is a longitudinal side view showing an example of a tandem image forming apparatus using an organic EL element as a light emitting element. In this image forming apparatus, four line heads 101K, 101C, 101M, and 101Y having the same configuration are exposed to four corresponding photosensitive members (image carriers) 41K, 41C, 41M, and 41Y having the same configuration. They are arranged at each position.

As shown in FIG. 12, this image forming apparatus is provided with a drive roller 51, a driven roller 52, and a tension roller 53. The intermediate transfer belt is circulated and driven in the direction indicated by the arrow (counterclockwise) by the tension roller 53. (Intermediate transfer medium) 50 is provided. Photosensitive members 41K, 41C, 41M, and 41Y are arranged at predetermined intervals with respect to the intermediate transfer belt 50.
K, C, M, and Y added after the reference sign mean black, cyan, magenta, and yellow, respectively. The photoconductors 41 </ b> K to 41 </ b> Y are driven to rotate in the direction indicated by the arrow (clockwise) in synchronization with the driving of the intermediate transfer belt 50. Around each photoconductor 41 (K, C, M, Y), charging means 42 (K, C, M, Y) and a line head 101 (K, C, M, Y) are provided.

  Further, a developing device 44 (K, C, M, Y) that applies a toner as a developer to the electrostatic latent image formed by the line head 101 (K, C, M, Y) to form a visible image; The primary transfer roller 45 (K, C, M, Y) and the cleaning device 46 (K, C, M, Y) are included. The emission energy peak wavelength of each line head 101 (K, C, M, Y) and the sensitivity peak wavelength of the photoconductor 41 (K, C, M, Y) are set to substantially coincide.

  The black, cyan, magenta, and yellow toner images formed by the four-color single-color toner image forming station are intermediated by the primary transfer bias applied to the primary transfer roller 45 (K, C, M, Y). The toner image, which is sequentially primary transferred onto the transfer belt 50 and sequentially superposed on the intermediate transfer belt 50 to become a full color, is secondarily transferred to a recording medium P such as paper by a secondary transfer roller 66, and serves as a fixing unit. The toner is fixed on the recording medium P by passing through the fixing roller pair 61, and is discharged onto a paper discharge tray 68 formed in the upper part of the apparatus by a paper discharge roller pair 62.

  63 is a paper feed cassette in which a large number of recording media P are stacked and held, 64 is a pickup roller for feeding the recording media P from the paper feed cassette 63 one by one, and 65 is a secondary transfer portion of the secondary transfer roller 66. A pair of gate rollers for defining the supply timing of the recording medium P to the roller, 66 is a secondary transfer roller as a secondary transfer means for forming a secondary transfer portion with the intermediate transfer belt 50, and 67 is an intermediate after the secondary transfer. This is a cleaning blade that removes toner remaining on the surface of the transfer belt 50.

  In the embodiment of the present invention, an LED, an organic EL, a VCSEL (Vertical Cavity Surface Emitting Laser (Vertical Cavity Surface Emitting Laser)), or the like can be used as a light emitting element of the light emitter array. Moreover, as a lens array, SLA (Selfoc Lens Array), MLA (Micro Lens Array), etc. can be used.

  The line head control method and the image forming apparatus using the line head control method that corrects the exposure position deviation and the like of the present invention and suppresses the deterioration of the image quality have been described above based on the embodiments. However, the present invention is limited to these embodiments. Various modifications are possible.

It is a block diagram which shows embodiment of this invention. It is a block diagram which shows embodiment of this invention. It is explanatory drawing which shows the related technique of this invention. It is explanatory drawing which shows embodiment of this invention. It is explanatory drawing which shows embodiment of this invention. It is explanatory drawing which shows embodiment of this invention. It is explanatory drawing which shows embodiment of this invention. It is a block diagram which shows embodiment of this invention. It is explanatory drawing which shows embodiment of this invention. It is explanatory drawing which shows embodiment of this invention. It is explanatory drawing which shows embodiment of this invention. 1 is a longitudinal side view of an image forming apparatus according to an embodiment of the present invention.

Explanation of symbols

  4, 5, 8 ... imaging lens, 6 ... light emitting element group (block), 7a-7b ... light emitting element row, 20 ... head controller, 21 ... print controller, 22. ..Mechanical controller, 23... EEPROM communication control unit, 24... Driver IC, 25... EEPROM, 26... Video I / F, 27.・ ・ ・ Head control signal generation unit, 29 ・ ・ ・ Request signal generation unit, 30 ・ ・ ・ Register, 31 ・ ・ ・ Write address generation unit, 32 ・ ・ ・ In-lens data order conversion unit, 41 (Y, M, C, K) ... photosensitive member, 101 (Y, M, C, K) ... line head, P ... recording medium, Y, M, C, K ... image forming station, A to C ... Light emitting element group rows

Claims (8)

A substrate, a light emitter array in which a plurality of light emitting elements are arranged on the substrate along the axial direction of the photosensitive member to form a light emitting element group row, and an imaging lens array provided corresponding to the light emitter array; The light emitter array and the imaging lens array are arranged in a plurality of rows with respect to the rotation direction of the photoconductor, and a line that forms a latent image at a different position for each row with respect to the rotation direction of the photoconductor Have a head,
The light emitting element is divided into a plurality along the axial direction of the photoconductor to form a block,
Perform rearrangement processing of pixel data corresponding to the light emitting elements in the block, and transmission delay processing of the pixel data,
A method of controlling a line head, comprising correcting a curvature deviation caused by manufacturing accuracy of the line head, a skew deviation caused by accuracy of mounting of the main body, and an exposure position deviation of the photosensitive member. 2. The method of controlling a line head according to claim 1, wherein the block unit is a plurality of light emitting elements corresponding to one lens of the imaging lens array. The line head according to claim 1, wherein the pixel data rearrangement process is a rearrangement process of a light emission order corresponding to a lens having a negative optical magnification of the imaging lens array. Control method. The transmission delay process of the pixel data is a process of correcting an exposure position shift for forming a latent image at a position different for each row with respect to the photoconductor. A method of controlling a line head according to claim 1. A light-emitting element of a line head that forms a latent image at a different position for each row with respect to the photosensitive member, and curvature correction information for correcting the curvature deviation, skew correction information for correcting the skew deviation, and 5. The control of a line head according to claim 1, further comprising storage means for storing light emitting element row correction information for correcting the exposure position shift of the row as correction information. Method. Before performing the curvature deviation amount measurement for obtaining the curvature correction information and the skew deviation amount measurement for obtaining the skew correction information, the light emission sequence corresponding to the lens having a negative optical magnification is arranged. 6. The method for controlling a line head according to claim 3, wherein a replacement process is performed. Before performing the curvature deviation amount measurement for obtaining the curvature correction information and the skew deviation amount measurement for obtaining the skew correction information, the exposure position deviation of the light emitting element rows according to the light emitting element row correction information. The line head control method according to claim 1, wherein the line head is corrected. An image forming unit including a charging unit, a line head controlled by the method according to any one of claims 1 to 7, a developing unit, and a transfer unit is disposed around the image carrier. An image forming apparatus, wherein at least two image forming stations are provided, and a transfer medium passes through each of the image forming stations to form an image in a tandem manner.

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