JP2009139449A - Image forming method and image forming apparatus using the same - Google Patents

Abstract

An image forming method using an imaging lens having a negative optical magnification and an image forming apparatus using the same.
A head controller, a print controller, and a mechanical controller are provided as control means for the line head. The print controller 21 includes an image processing unit 21a, and the head controller 20 includes a main scanning direction printing position deviation correction unit 25, a video (Video) I / F unit 26, and a sub scanning direction exposure position deviation correction. 27, a line head control signal generation unit 28, a request signal generation unit 29, a register 30, and a write address generation unit 31 are provided. Sub-scanning exposure position deviation correction is performed after main-scanning direction printing position deviation correction.
[Selection] Figure 1

Description

  The present invention relates to an image forming method and an image forming apparatus using the same, in which image quality deterioration due to a printing position shift when an imaging lens having a negative optical magnification is used.

  As an exposure light source of an image forming apparatus, a configuration in which a line head using an LED or an organic EL is installed is known. Patent Document 1 describes a method for correcting color misregistration in the main scanning direction of a toner image transferred onto a recording sheet. In this color misregistration correction procedure, (1) a registration mark for detecting a color misregistration amount is formed on a transfer belt. (2) The position of the registration mark formed on the transfer belt is detected by a reflective photosensor. (3) A color misregistration correction amount in the main scanning direction is calculated based on a detection signal output from the reflective photosensor. (4) A white pixel amount for forming a blank portion inserted at an end of the exposure apparatus in the main scanning direction is adjusted according to a color misregistration correction amount.

JP 2004-133217 A

  Japanese Patent Application Laid-Open No. H10-228561 describes a color misregistration correction method in the axial direction (main scanning direction) of a photoreceptor in a tandem image forming apparatus. However, in the monochrome and 4-cycle image forming apparatuses, there is no description about the registration adjustment method (centering the printing position with respect to the recording paper) in the axial direction of the photosensitive member, and the monochrome and 4-cycle methods. In this image forming apparatus, there is a problem that it is unclear how to adjust the resist in the axial direction of the photosensitive member. In addition, in a microlens array (MLA) line head using a microlens with a negative optical magnification as an imaging lens array, the conventional color misregistration correction in the main scanning direction as described in Patent Document 1 above. However, since the exposure position shift for each light emitting element row specific to the MLA line head and the light emission order corresponding to the negative optical magnification lens are not considered, the processing order is not appropriate (data arrangement corresponding to the negative optical magnification). There has been a problem that a latent image different from the original image is formed.

  The present invention has been made in view of the above-described problems of the prior art, and an object thereof is a line that suppresses image quality degradation caused by a printing position shift when an imaging lens having a negative optical magnification is used. It is an object to provide a head control method and an image forming apparatus using the same.

The image forming method of the present invention that achieves the above-described object comprises:
A substrate,
A light emitter array in which a plurality of light emitting elements are arranged along the axial direction of the photoreceptor on the substrate to form a light emitting element row;
An imaging lens having a negative optical magnification provided corresponding to the light emitter array;
Having a line head with
After correction of the printing position deviation of the toner image in the axial direction of the photosensitive member, in-lens data order conversion which is data rearrangement corresponding to the imaging lens having a negative optical magnification is performed.

The image forming method of the present invention includes
A substrate,
A light-emitting array in which a plurality of light-emitting element rows in which a plurality of light-emitting elements are arranged on the substrate along the axial direction of the photoconductor are formed in the rotation direction of the photoconductor;
An imaging lens having a negative optical magnification provided corresponding to the light emitter array;
A line head for forming a latent image at a different position for each light emitting element row with respect to the photoconductor,
After correcting the misalignment of the printing position of the toner image in the axial direction of the photoconductor, a process of correcting a latent image formed at a different position for each light emitting element row is performed, and then the image with the negative optical magnification is formed. In-lens data order conversion, which is data rearrangement corresponding to the lens, is performed.

The image forming method of the present invention includes
A substrate,
A light-emitting array in which a plurality of light-emitting element rows in which a plurality of light-emitting elements are arranged on the substrate along the axial direction of the photoconductor are formed in the rotation direction of the photoconductor;
An imaging lens having a negative optical magnification 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,
It has a line head for forming a latent image at a different position for each light emitting element row with respect to the photoconductor, and performs processing in the following order.
(1) Correction of a printing position shift of the toner image in the axial direction of the photoconductor.
(2) A latent image formed at a different position for each light emitting element row is corrected.
(3) A latent image formed at a different position for each light emitting element group row is corrected.
(4) In-lens data order conversion, which is data rearrangement corresponding to an imaging lens having a negative optical magnification, is performed.

The image forming method of the present invention includes
The correction of the latent image formed at a different position for each light emitting element row is correction of curvature deviation caused by the manufacturing accuracy of the line head and skew deviation caused by the body mounting accuracy.

  The image forming method of the present invention is characterized in that the light emitting element group row correction is correction of an inter-row exposure position shift of the imaging lens.

  In the image forming method of the present invention, the correction information for correcting the printing position deviation of the toner image in the axial direction of the photoconductor, the light emitting element row correction information, and the light emitting element group row correction information are used as correction information. Storage means for storing is provided.

Further, the image forming method of the present invention counts 0 to the total number of dots formed in the axial direction of the photoconductor to generate a first write address in units of pixel data length,
Adding the bank address, the read light emitting element row correction information, and the light emitting element group row correction information to generate a second write address;
The first write address and the second write address are combined to generate the write address of the storage means.

  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. And a transfer medium passes through each of the image forming stations to form an image by a 4-cycle method or a monochrome method.

  The present invention will be described below with reference to the drawings. FIG. 11 is an explanatory diagram showing an embodiment of the present invention. FIG. 11A 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. 11B is a relationship between the single imaging lens 4 and the light emitting element group 6. FIG. As shown in FIG. 11A, 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. 11A, 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. 11B, 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 photoconductor, and in the example of FIG. 11B, light emitting element rows 7a, 7b, and 7c are provided. As described above, FIGS. 11A and 11B 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. 12 and 13 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 as shown in FIG. 11 correspond to each other. In FIG. 12, 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. 13A is formed on the photoreceptor.

  In FIG. 13A, 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. 13B 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 the same as the original image and is formed in one linear shape in the axial direction (main scanning direction) of the photoreceptor. 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. 13A, 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 can be corrected by controlling the light emitting element in the block unit. In addition, by correcting the printing position deviation of the toner image in the axial direction of the photoreceptor first, and then correcting 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. This prevents 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. 2 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. 2, 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. 3 is an explanatory diagram of an example in which a microlens having a negative optical magnification is used. In FIG. 3, the light-emitting elements 2 are arranged in the order of ○ 1 to ○ 60 as in FIG. 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. 2, 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 of a control unit in the embodiment of the present invention. In FIG. 1, 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 a main scanning direction printing position deviation correction unit 25, a video (Video) I / F unit 26, and a sub scanning direction exposure position deviation correction. 27, a line head control signal generation unit 28, a request signal generation unit 29, a register 30, and a write address generation unit 31 are provided.

  The main scanning direction printing position deviation correction unit 25 is provided with a delay circuit 25a, and the sub-scanning direction exposure position deviation correction unit 27 is provided with an SRAM. Further, the register 30 is provided with a storage unit 30a for storing main-scanning direction printing position deviation information, and a storage unit 30b for storing light emitting element row correction information and light emitting element group row correction information.

  Prior to factory shipment, the light emitting element row correction information and the light emitting element group row correction information are stored in the storage unit 30b in the register 30 of the head controller 20 (◯ 1). Also, main-scanning direction printing position deviation correction information is stored in the storage unit 30a (◯ 1). Here, the light emitting element row correction information and the light emitting element group row correction information are values obtained by converting the unit of the design value (μm) of the light emitting element arrangement of the MLA + line head into a line unit. The main scanning direction positional deviation correction information is a value obtained by converting a unit (μm) obtained by measuring a printing positional deviation amount in the main scanning direction with an optical sensor or the like before shipment from the factory into a dot unit.

  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 main scanning direction printing position deviation correction unit 25, 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 the converted image data to the main-scanning direction print position misalignment correction unit 25 (◯ 4). The main scanning direction printing position deviation correction unit 25 is inserted at the end in the main scanning direction based on the main scanning direction printing position deviation information stored in the main scanning direction printing position deviation correction information storage means 30a of the register 30. Adjust the margins in dots. When adjusting the margin, the time from the Hreq signal until the head data of the line data is output is controlled by a delay circuit (Philip flop). Thereafter, the image data corrected in the main scanning direction printing position deviation is transmitted to the sub-scanning direction deviation correction unit 27.

  In the example of FIG. 1, a delay circuit (Philip flop) 25 a is provided in the main-scanning direction print position deviation correction unit 25. Although the margin portion is adjusted by the delay circuit 25a, the margin portion may be corrected by using a line buffer to which a memory corresponding to the printing position deviation amount in the main scanning direction is added. That is, when one line data sent from the Video I / F unit is stored in the line buffer, dummy data (0 data) corresponding to the detected printing position deviation amount in the main scanning direction is added to the head of the line data. Thus, the margin part inserted at the end in the main scanning direction is corrected.

  The sub-scanning direction deviation correction unit 27 writes the order-converted image data to the SRAM according to the write address generated by the write address generation unit 31. By performing such processing, the sub-scanning direction deviation (light emitting element row deviation, light emitting element group row deviation) due to the arrangement of the light emitting elements peculiar to MLA is corrected (（6). The write address generation unit 31 generates a write address based on the light emitting element row correction information and the light emitting element group row correction information stored in the register. A method for generating the write address will be described later.

  When the sub-scanning direction deviation corrected image data stored in the SRAM of the sub-scanning direction deviation correction unit 27 is read, the image data is rearranged in the light emission order corresponding to the negative optical magnification shown in FIG. Data order conversion, 7). For example, in the case of the light emitting element arrangement shown in FIG. 3, the read address is {59, 58,..., 1, 0, 119, 118,..., 61, 60, 179, 178.

  Such processing is to invert the readout address for each lens. The corrected data is transmitted to the line head 10 (○ 8). 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. 4 is an explanatory diagram showing an image data writing image 33 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 in FIG. 12, the light emitting element group is 3 groups (A, B, C), the light emitting element rows in the group are 3 rows (1, 2, 3), and between the light emitting element rows. 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 printing position deviation amount in the main scanning direction is 2 dots. Shall. Further, the amount of curve / skew deviation in the sub-scanning direction is 2 lines for block No 0 and 1 line for block No 1. In FIG. 11A, the block of the light emitting element is arranged corresponding to each imaging lens. However, in the example of FIG. 4, the block of the light emitting element is not associated with the imaging lens. . In FIG. 4, 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. 4, 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, nine light emitting elements are arranged in one microlens, but since the amount of misalignment in the printing position in the main scanning direction is 2 dots, the number of light emitting elements in the head microlens is adjusted to seven. Yes.

  Since 15 light emitting elements are arranged in one block, the dividing lines are written in the portions 14 and 31 of the line address. Thus, the block unit is a number of non-integer multiples of the number of light emitting elements corresponding to one lens of the imaging lens array (in this example, 9 excluding the head) (15 in this example). ). In the example of the light emitting element group A, when the block number is 0, pixel data D1, D4, and D7 are written in BANK2. Since the pixel data D1 has a printing position deviation amount of 2 dots in the main scanning direction, it corresponds to the line address “2”.

  Pixel data D3 and D6 are written in BANK4, which is shifted from BANK2 in the two-line sub-scanning direction. Further, pixel data D2 and D5 are written in BANK6. In FIG. 4, the arrangement of pixel data is two each for BANK4 and BANK6. For example, dummy data may be stored at address 1 in BANK4 and dummy data may be stored at address 0 in BANK6.

  For the light emitting element group B, nine pixel data D8 to D16 are stored across the block numbers “0” and “1”. For the light emitting element group C, nine pixel data D17 to D25 are stored in the block No. “1”. Subsequent to the light emitting element group C, the pixel data D <b> 26 and below of the light emitting element group A are stored again from the line address 27.

  In the embodiment of the present invention, in a line head that forms a latent image at a different position for each light emitting element row with respect to the photoconductor, first, correction of the printing position deviation in the main scanning direction is performed, and then the light emitting element row varies. Light-emitting element row correction that corrects the latent image formed at the position and light-emitting element group row correction, followed by in-lens data order conversion that is data rearrangement corresponding to an imaging lens with a negative optical magnification It is. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 5 is an explanatory diagram showing a related technique of the present invention. In FIG. 5, the main-scanning-direction printing position deviation correction and the deviation correction in the rotation direction (sub-scanning direction) of the photosensitive member (the curve head skew / skew correction, the light-emitting element row correction, and the light-emitting element group row correction) ), And in-lens data conversion when an imaging lens having a negative optical magnification is used. In the example of FIG. 5, there are 18 light emitting elements in an imaging lens with one optical magnification minus, and the light emitting element rows are configured to be 3 rows.

  That is, three light emitting element rows of light emitting elements 1 to 16, 2 to 17, and 3 to 18 are formed. There are six light emitting elements in each light emitting element row, and 18 in one imaging lens. The light emitting elements are arranged. Therefore, the number of light emitting elements in one imaging lens is different from the example of FIG. 4 (9 light emitting elements are arranged in one imaging lens). In addition, there is a shift of two lines in the sub-scanning direction between the light emitting element rows.

  FIG. 5A shows the original image data in the memory area 34. In this example, the skew correction is 0 because the line head curve / skew correction is not performed. Further, since the light emitting element rows and the light emitting element group rows that form latent images at different positions in the rotation direction of the photosensitive member are not corrected, the data transmission delay amount is also zero. Thus, in FIG. 5A, the deviation correction amount in the rotation direction of the photosensitive member is zero. Further, as described above, neither the printing position deviation correction nor the in-lens data conversion in the main scanning direction is performed.

  FIG. 5B shows the light emitting element surface 35 of the light emitter array. The 18 light emitting elements 1 to 18 form three light emitting element rows as described above. FIG. 5C shows an exposure spot 36 on the photoreceptor. When an imaging lens having a negative optical magnification is used, the output light of each light emitting element is reversed between the axial direction of the photosensitive member and the rotating direction of the photosensitive member. For this reason, the exposure spot 36 is formed at the position shown in the drawing.

  FIG. 5D shows a latent image formed on the photoconductor. Image data “11111” written in BANK0 to BANK4 in FIG. 5A is supplied to the light emitting element 1 shown in FIG. In the light emitting element rows 2 to 17, the light emitting element rows 2 to 17 operate with a delay of two lines from the light emitting element rows 1 to 16 in the rotation direction of the photosensitive member. In the light emitting element rows 3 to 18 as well, the light emitting element rows 3 to 18 operate with a delay of two lines from the light emitting element rows 2 to 17 in the rotation direction of the photosensitive member.

  For example, the light emitting element 1 operates with a delay of two lines from the light emitting element 2 with respect to the rotating direction of the photosensitive member, and the light emitting element 2 operates with a delay of two lines from the light emitting element 3 with respect to the rotating direction of the photosensitive member. To do. As shown in FIG. 5D, since no correction processing is performed, a latent image different from the original image in FIG. 5A is formed on the photoconductor. In the example of FIG. 5, the correction in the sub-scanning direction of the light-emitting element rows has been described, but actually, the correction in the sub-scanning direction of the light-emitting element group rows is also necessary.

  6 and 7 show a data flow and a latent image formed on the photosensitive member when processing is performed in the order of sub-scanning direction deviation correction → MLA correction → main scanning print position deviation correction. FIG. 6A shows image data after sub-scanning deviation correction stored in the memory area 34a. On the basis of the image data 1 to 16, the image data 2 to 17 correct the shift of two lines in the sub-scanning direction. Further, the image data 3 to 18 correct the shift of 2 lines in the sub-scanning direction than the image data 2 to 17, that is, the shift of 4 lines in the sub-scanning direction than the image data 1 to 16 is corrected.

  FIG. 6B shows image data 38 after data conversion in the main scanning direction in the MLA lens. For example, image data “11111” stored in BANKs 4 to 8 at address 0 is converted to BANKs 4 to 8 at address 17. Further, the image data “1818181818” stored in the BANKs 0 to 4 at the address 17 is converted into BANKs 0 to 4 at the address 0.

  FIG. 6C shows image data 39 obtained by shifting the image data 38 of FIG. 6B by 2 dots in the main scanning direction for correcting the printing position deviation. In this example, the image data “18” corresponding to address 0 is converted to address 2 which is shifted by 2 dots in the main scanning direction. Further, the image data “3” is converted from the address address 15 to the address address 17. Therefore, the image data “2” corresponding to the address 16 and the image data “1” corresponding to the address 17 are not shown in FIG. 6C.

  FIGS. 7A and 7B correspond to FIGS. 5B and 5C, respectively, and show the light emitting element surface 35 and the exposure spot 36 on the photoreceptor. FIG. 7C shows a latent image formed on the photoconductor. The latent image in FIG. 7C is formed by inverting the image data in FIG. 6C in the sub-scanning direction and shifting it by shifting two dots in the main scanning direction. As shown in FIG. 7C, if the processing order of the image data is inappropriate, an inferior latent image is formed on the photosensitive member instead of the original image.

  8 and 9 are explanatory diagrams according to the embodiment of the present invention. FIGS. 8 and 9 show a data flow and a latent image formed on the photosensitive member when processing is performed in the order of main-scanning direction printing position deviation correction → sub-scanning direction deviation correction → MLA correction. FIG. 8A shows image data after correction of the printing position deviation in the main scanning direction. That is, the image data 39a that has been previously corrected in the main scanning direction printing position deviation is stored with respect to the image data stored in the memory area 34 shown in FIG.

  Next, as shown in FIG. 8B, the image data 34b after the correction is performed by correcting the misalignment in the main scanning direction with respect to the image data stored in the memory area. Is stored in the memory area. Further, as shown in FIG. 8C, image data 38a after in-lens data conversion is formed.

  FIG. 9A shows a light emitting element surface 35 of the light emitter array, and FIG. 9B shows an exposure spot 36 on the photosensitive member. By rearranging the data corresponding to the MLA as described in FIG. 8, the same latent image as the original image data is formed on the photosensitive member as shown in FIG. 9C.

  The embodiment of the present invention can be applied to a line head including a light emitting element array and an imaging lens array as shown in FIG. In this case, as shown in FIG. 13, the light emitting element row correction for correcting the latent image formed at a different position for each light emitting element row and the latent image formed at a different position for each light emitting element group row. The light emitting element group row correction for correcting the image is performed. Thereafter, in-lens data order conversion, which is data rearrangement corresponding to an imaging lens having a negative optical magnification, is performed.

  Further, the embodiment of the present invention can be applied to an example in which the light emitting element of the line head as shown in FIG. 11 is divided into a plurality of block units along the axial direction of the photosensitive member. In this case, the block unit is formed by the number of light-emitting elements that is a non-integer multiple of the number of light-emitting elements corresponding to one lens of the imaging lens array, and is caused by the manufacturing accuracy of the line head in the block unit. After correcting the bending deviation and the skew deviation caused by the accuracy of mounting the main body, the data order in the imaging lens is converted.

  FIG. 10 is a block diagram illustrating an example of generating a write address 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 uses the clock signal (Clk) as a trigger to count up the line address and generate a write address 1 (first write address). 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 light emitting element row correction information management unit 73 reads the light emitting element row correction information (BANK unit) corresponding to each dot from the value of the line address.

  The light emitting element group row correction information management unit 74 reads light emitting element group row correction information (BANK unit) corresponding to each dot from the value of the line address. A write address 2 (second write address) is generated by adding the BANK address, the read light emitting element row correction information, and the light emitting element group row correction information. The write address 1 and the write address 2 are combined to generate the SRAM write address.

  The embodiment of the present invention can be applied to an image forming apparatus having a rotary configuration. FIG. 14 is a vertical side view of the image forming apparatus. In FIG. 14, the image forming apparatus 160 includes, as main constituent members, a rotary developing device 161, a photosensitive drum 165 functioning as an image carrier, and an image writing means (line head) 167 provided with an organic EL array. In addition, an intermediate transfer belt 169, a paper conveyance path 174, a fixing roller heating roller 172, and a paper feed tray 178 are provided.

  In the developing device 161, the developing rotary 161a rotates in the arrow A direction about the shaft 161b. The inside of the development rotary 161a is divided into four, and image forming units for four colors of yellow (Y), cyan (C), magenta (M), and black (K) are provided. Reference numerals 162a to 162d are arranged in the image forming units for the four colors. The developing rollers rotate in the arrow B direction, and the toner supply rollers 163a to 163d rotate in the arrow C direction. Reference numerals 164a to 164d are regulating blades that regulate the toner to a predetermined thickness.

  As described above, reference numeral 165 denotes a photosensitive drum that functions as an image carrier, 166 denotes a primary transfer member, 168 denotes a charger, and 167 denotes an image writing unit, which is provided with an organic EL array. The photosensitive drum 165 is driven in the direction of arrow D opposite to the developing roller 162a by a drive motor (not shown), for example, a step motor.

  The intermediate transfer belt 169 is stretched between the driven roller 170b and the drive roller 170a, and the drive roller 170a is connected to the drive motor of the photosensitive drum 165 to transmit power to the intermediate transfer belt. By driving the drive motor, the drive roller 170 a of the intermediate transfer belt 169 is rotated in the arrow E direction opposite to the photosensitive drum 165.

  The paper conveyance path 174 is provided with a plurality of conveyance rollers, a pair of paper discharge rollers 176, and the like, and conveys the paper. An image (toner image) on one side carried on the intermediate transfer belt 169 is transferred to one side of the paper at the position of the secondary transfer roller 171. The secondary transfer roller 171 is separated from and brought into contact with the intermediate transfer belt 169 by a clutch, and is brought into contact with the intermediate transfer belt 169 when the clutch is turned on, so that an image is transferred onto the sheet.

  The sheet on which the image has been transferred as described above is then subjected to a fixing process by a fixing device having a fixing heater H. The fixing device is provided with a heating roller 172 and a pressure roller 173. The sheet after the fixing process is drawn into the discharge roller pair 176 and proceeds in the arrow F direction. When the paper discharge roller pair 176 rotates in the opposite direction from this state, the paper reverses its direction and advances in the double-sided printing conveyance path 175 in the arrow G direction. 177 is an electrical component box, 178 is a paper feed tray for storing paper, and 179 is a pickup roller provided at the outlet of the paper feed tray 178.

  For example, a low-speed brushless motor is used as a drive motor for driving the transport roller in the paper transport path. The intermediate transfer belt 169 uses a step motor because it requires color misregistration correction. Each of these motors is controlled by a signal from a control means (not shown).

  In the state shown in the drawing, a yellow (Y) electrostatic latent image is formed on the photosensitive drum 165, and a high voltage is applied to the developing roller 62a, whereby a yellow image is formed on the photosensitive drum 165. When all of the yellow back side and front side images are carried on the intermediate transfer belt 169, the development rotary 161a rotates 90 degrees in the direction of arrow A.

  The intermediate transfer belt 169 rotates once and returns to the position of the photosensitive drum 165. Next, two images of cyan (C) are formed on the photosensitive drum 165, and this image is carried on the yellow image carried on the intermediate transfer belt 169. Thereafter, the 90-degree rotation of the development rotary 161 and the one-rotation process after the image is carried on the intermediate transfer belt 169 are repeated in the same manner.

  For carrying four color images, the intermediate transfer belt 169 rotates four times, and then the rotation position is further controlled to transfer the image onto the sheet at the position of the secondary transfer roller 171. The paper fed from the paper feed tray 178 is transported by the transport path 174, and the color image is transferred to one side of the paper at the position of the secondary transfer roller 171. The sheet on which the image is transferred on one side is reversed by the discharge roller pair 176 as described above, and stands by on the conveyance path. Thereafter, the sheet is conveyed to the position of the secondary transfer roller 171 at an appropriate timing, and the color image is transferred to the other side. The housing 180 is provided with an exhaust fan 181. In this example, since an image is formed on the transfer medium by one transfer member (secondary transfer roller 171), one image forming station is provided.

  FIG. 15 is a vertical side view of an image forming apparatus showing a different embodiment of the present invention. FIG. 14 is intended for a four-color rotary color image forming apparatus, but FIG. 15 is intended for a monochrome (monochrome) image forming apparatus. Detailed description is omitted, and only the main part will be described. In FIG. 15, an image forming apparatus 160a includes, as main constituent members, a developing device 161a, a photosensitive drum 165a that functions as an image carrier, a transfer member 166a, a line head 167a, a charging device 168a, a fixing roller pair 172a, and a sheet conveyance path. 174a, a paper feed tray 178a, and a paper feed roller 179a are provided. In this example, since one transfer member 166a forms an image on the transfer medium, one image forming station is provided.

  The developing device 161a is provided with a stirring blade 164x that stirs the toner 169a stored in the toner tank 166a, a toner supply roller 163b, and a developing roller 162a. Similarly to the image forming apparatus in FIG. 14, the image forming apparatus in FIG. 15 is an image forming station in which charging units, line heads, developing units, and transfer units are arranged around the image carrier. And the transfer medium passes through the image forming stations to form an image on the transfer medium.

  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.

  The embodiment of the present invention is an image forming apparatus that includes a line head and a negative optical magnification MLA (Micro Lens Array) and corrects color misregistration in the main scanning direction. By correcting the exposure position shift in the order of “correction”, the conventional color shift correction in the main scanning direction, the exposure position shift correction for each light emitting element row specific to the MLA line head, and the exposure position shift correction for each light emitting element group row , And the light emission order conversion corresponding to the negative optical magnification lens can be corrected correctly. For this reason, a high-quality image can be provided to the user.

  As described above, the image forming method and the image forming apparatus using the image forming method in which the exposure position deviation of the present invention is corrected and the image quality deterioration when the imaging lens having a negative optical magnification is used have been described based on the embodiments. However, the present invention is not limited to these examples, and various modifications are possible.

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 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 the related technique of this invention. It is explanatory drawing which shows the related technique 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 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. 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, 7a-7b ... light emitting element row, 20 ... head controller, 21 ... print controller, 22 ... mechanism Controller, 24... Driver IC, 25... Main-scanning direction print position deviation correction unit, 26... Video I / F, 27. Signal generation unit 29 ... Request signal generation unit 30 ... Register 31 ... Write address generation unit 161 ... Developing device 165 ... Photosensitive drum 167 ... Line head 169: Intermediate transfer belt, 171: Secondary transfer roller, 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 along the axial direction of the photoreceptor on the substrate to form a light emitting element row;
An imaging lens having a negative optical magnification provided corresponding to the light emitter array;
Having a line head with
After correcting the printing position deviation of the toner image in the axial direction of the photoconductor, the in-lens data order conversion which is data rearrangement corresponding to the imaging lens having a negative optical magnification is performed. Line head control method. A substrate,
A light-emitting array in which a plurality of light-emitting element rows in which a plurality of light-emitting elements are arranged on the substrate along the axial direction of the photoconductor are formed in the rotation direction of the photoconductor;
An imaging lens having a negative optical magnification provided corresponding to the light emitter array;
A line head for forming a latent image at a different position for each light emitting element row with respect to the photoconductor,
After correcting the misalignment of the printing position of the toner image in the axial direction of the photoconductor, a process of correcting a latent image formed at a different position for each light emitting element row is performed, and then the image with the negative optical magnification is formed. A method for controlling a line head, comprising performing in-lens data order conversion which is data rearrangement corresponding to a lens. A substrate,
A light-emitting array in which a plurality of light-emitting element rows in which a plurality of light-emitting elements are arranged on the substrate along the axial direction of the photoconductor are formed in the rotation direction of the photoconductor;
An imaging lens having a negative optical magnification 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,
A method for controlling a line head, comprising: a line head for forming a latent image at a different position for each light emitting element row with respect to the photosensitive member; and performing processing in the following order.
(1) Correction of a printing position shift of the toner image in the axial direction of the photoconductor.
(2) A latent image formed at a different position for each light emitting element row is corrected.
(3) A latent image formed at a different position for each light emitting element group row is corrected.
(4) In-lens data order conversion, which is data rearrangement corresponding to an imaging lens having a negative optical magnification, is performed. The correction of the latent image formed at a different position for each light emitting element row is correction of a curvature deviation caused by the manufacturing accuracy of the line head and a skew deviation caused by the body mounting accuracy. The method of controlling a line head according to claim 2 or claim 3. 5. The line head control method according to claim 3, wherein the light emitting element group row correction is an inter-row exposure position shift correction of the imaging lens. 6. And a storage unit that stores correction information for correcting a printing position shift of the toner image in the axial direction of the photoconductor, the light emitting element row correction information, and the light emitting element group row correction information as correction information. A method for controlling a line head according to any one of claims 1 to 5. Counting 0 to the total number of dots formed in the axial direction of the photoconductor to generate a first write address in pixel data length units;
Adding the bank address, the read light emitting element row correction information, and the light emitting element group row correction information to generate a second write address;
7. The line head control method according to claim 6, wherein the first write address and the second write address are combined to generate a write address of the storage means.   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 one image forming station is provided, and a transfer medium passes through each of the image forming stations to form an image by a 4-cycle method or a monochrome method.

Images