JP2008168562A - Image forming device and image formation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device which can smoothly and reasonably form images when light emitting elements are two-dimensionally arranged in a microlens. <P>SOLUTION: A plurality of the microlenses 5 whose optical magnifications are minus are arranged in an axial direction (main scanning direction, X direction) of an image carrier and the direction intersecting the axial direction at right angles (subsidiary direction, Y direction). In each of the microlenses 5, a plurality of light-emitting element lines where a plurality of light-emitting elements are arranged in a main scanning direction are arranged in the subsidiary scanning direction to arrange the light-emitting elements two-dimensionally in an emitter array in the form of a matrix. The output light of the light-emitting elements reversely forms an image on an image carrier by the microlenses 5. Image data is stored in a memory so as to ensure that a row of images are formed in the main scanning direction of the image carrier. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus and an image forming method that can smoothly and rationally form an image when a light-emitting element is two-dimensionally arranged on a light emitter array using a lens having a negative optical magnification. is there.

  In general, an electrophotographic toner image forming unit includes a photosensitive member as an image bearing member having a photosensitive layer on an outer peripheral surface, a charging unit that uniformly charges the outer peripheral surface of the photosensitive member, and a uniform charging unit using the charging unit. An exposure unit that selectively exposes the outer peripheral surface charged to form an electrostatic latent image, and a toner as a developer is applied to the electrostatic latent image formed by the exposure unit to form a visible image ( Developing means for forming a toner image).

  As a tandem type image forming apparatus for forming a color image, a plurality (for example, four) of toner image forming means as described above are arranged on the intermediate transfer belt. The toner images on the photoconductor by these single color toner image forming means are sequentially transferred to an intermediate transfer belt, and a plurality of colors (for example, yellow, cyan, magenta, black (black) toner images are superimposed on the intermediate transfer belt, There is an intermediate transfer belt type that obtains a color image on an intermediate transfer belt.

  In a tandem color image forming apparatus (printer), a technique using a light emitter array as the exposure means (line head) is known. For example, Patent Document 1 describes an example in which a latent image is formed by magnifying output light of a light emitting element arranged two-dimensionally in a light emitter array with a single lens and irradiating the photosensitive drum. . Patent Document 2 describes an example in which the writing position on the image plane (image carrier) is reversed from the position of the light emitting source by a microlens array arranged in the longitudinal direction of the LED array chip.

JP 2001-63139 A JP-A-8-166555

  In the light emitter array described in Patent Document 1, as shown in FIG. 1 of Patent Document 1, the single lens 14 reverses the output light of the light emitting member 1 in the main scanning direction, and the photosensitive drum 15. Irradiating. That is, the single lens 14 uses a microlens having a negative optical magnification. Therefore, unlike SLA (Selfoc lens array), the optical magnification is positive and the output light of the light emitting element is different from the case where the image carrier is irradiated in the optical axis direction.

  When a light emitter array in which a microlens is provided in an optical system as described in Patent Document 1 is used as a line head, image data stored in a memory is used for smooth image formation. A specific memory configuration and a read sequence of image data are required for how to read out and perform predetermined printing. However, Patent Document 1 only describes a configuration using a single lens. A memory configuration in the case where a light source is arranged two-dimensionally and a plurality of lenses are used, and a specific image data reading sequence are described. There was a problem that the example was not described. In addition, in the example described in Patent Document 2, it is generally only described that the writing position on the image carrier is reversed when the light emission sources are arranged in a straight line. For this reason, there is a problem that it is unclear how to deal with the case where the light emitting sources are arranged two-dimensionally and how to store the data in the memory.

  The present invention has been made in view of such problems of the prior art, and an object of the present invention is to form an image when a plurality of lenses in which light sources are arranged two-dimensionally and optical magnification is negative is used. An object of the present invention is to provide an image forming apparatus and an image forming method that can be performed smoothly and rationally.

  The image forming apparatus of the present invention that achieves the above object has a lens having a negative optical magnification and a line head provided with a light emitter array in which a plurality of light emitting elements are arranged, and the lens is in the axial direction of the image carrier ( A plurality of light emitting element lines arranged in the main scanning direction in the sub scanning direction are provided in correspondence with the main scanning direction) and a direction orthogonal to the axial direction (sub scanning direction). Corresponding light emitter blocks made up of m × n light emitting elements arranged in n rows, and driving each light emitting element in the axial direction and in the direction perpendicular to the axial direction to form an image on the image carrier It has the control means to do.

  In the image forming apparatus of the present invention, the control means outputs, in the axial direction of the image carrier, output light of m × n light emitting elements provided corresponding to the lenses arranged in the axial direction. One row of images is formed.

  In the image forming apparatus of the present invention, the control unit may output the image with output light of m × n light emitting elements provided corresponding to the lenses arranged in the axial direction and a direction orthogonal to the axial direction. A plurality of rows of images formed in a line in the axial direction of the carrier are formed in a direction perpendicular to the axial direction.

  In the image forming apparatus of the present invention, the m × n-th light emitting element of the light emitter block corresponding to each of the lenses is arranged in one row in a direction perpendicular to the axial direction on the tip end side in the axial direction of the light emitter array. The first light emitting elements of the light emitter block are arranged in the nth column on the rear end side in the axial direction and in the direction orthogonal to the axial direction.

  Further, the image forming apparatus of the present invention is provided with storage means for storing image data to be supplied to each light emitting element, and the storage means is sequentially arranged in one column along the axial direction from the axial writing position of the image carrier. The image data is stored so that an image is formed on the screen.

  In the image forming apparatus according to the aspect of the invention, the storage unit sequentially forms images in one column along the axial direction from the axial writing position of the image carrier, and images in the direction orthogonal to the axial direction. The image data is stored so that a plurality of columns are formed.

  In the image forming apparatus according to the aspect of the invention, the control unit may store the image data stored in the storage unit in the order of the nth column, the n−1th column,. Each light emitting element is driven by reading out.

  The image forming apparatus of the present invention is characterized in that a plurality of the line heads are provided corresponding to the respective colors, and image formation of a plurality of colors is simultaneously performed on the image carrier.

  In the image forming apparatus of the present invention, the light emitting element is an organic EL element.

  The image forming apparatus of the present invention is provided with at least two or more image forming stations in which the image forming units of the line head, the developing unit, and the transfer unit described above are arranged, and the transfer medium is provided for each of the transfer media. By passing through the station, image formation is performed by a tandem method.

  In addition, the image forming apparatus of the present invention includes an intermediate transfer medium.

The image forming method of the present invention includes a plurality of lenses having a negative optical magnification and arranged in an axial direction (main scanning direction) of the image carrier and a direction orthogonal to the axial direction (sub-scanning direction). A line head having a light emitter array corresponding to a light emitter block composed of m × n light emitting elements in which light emitting element lines in which m light emitting elements are arranged in the main scanning direction is arranged in n columns in the sub scanning direction is provided for each color. A plurality are provided corresponding to
Image data is formed so that images are sequentially formed in one column along the axial direction from the axial writing position of the image carrier on the storage means, and a plurality of images are formed in a direction orthogonal to the axial direction. Storing the data, reading the image data stored in the storage means, driving the light emitting elements in the axial direction and in the direction orthogonal to the axial direction by driving the read image data, And the step of simultaneously forming images of a plurality of colors on the image carrier.

  The image forming method of the present invention is characterized in that the reading of the image data is performed in the order of the nth column, the n−1th column,.

  In the embodiment of the present invention, a plurality of lenses having negative optical magnification are provided in the axial direction (main scanning direction) of the image carrier and the direction orthogonal to the axial direction (sub-scanning direction). Image formation by an image forming apparatus using a line head in which light emitting element lines in which m light emitting elements are arranged in the direction and m × n light emitting elements arranged in n rows in the sub-scanning direction are associated with each other Can be performed smoothly and rationally.

  Further, the storage means stores image data in a form suitable for such an image forming apparatus, and the image data is driven so that each light emitting element is driven in the axial direction and in a direction perpendicular to the axial direction. Since the data is read from the storage unit, a predetermined image created by a controller or the like can be accurately formed on the image carrier.

  Further, since an organic EL element is used as the light emitting element and the diameter of the light emitting part does not have to be reduced, the light power of the light emitting part can be increased. For this reason, it is possible to use an organic EL material having a low luminous efficiency. Such an image forming apparatus can be applied particularly to a tandem color image forming apparatus.

  A configuration which is a premise of the present invention will be described with reference to FIGS. 15 to 20. In the specification and drawings of the present invention, the longitudinal direction of the light emitter array used as the line head is defined as the main scanning direction (X direction), and the moving direction of the image carrier is defined as the sub scanning direction (Y direction). Then, the configuration of the line head will be described in three dimensions as necessary, along with the vertical direction (Z direction) of the light emitter array. Here, the longitudinal direction of the light emitter array corresponds to the axial direction of the photoconductor configured as an image carrier, and the moving direction of the image carrier corresponds to the direction orthogonal to the axial direction of the photoconductor. .

  FIG. 16 is a schematic explanatory view showing an example of a light emitter array used as a line head in the embodiment of the present invention. In FIG. 16, in the light emitter array 1, a plurality of light emitting element lines 3 in which a plurality of light emitting elements 2 are arranged in the main scanning direction (X direction) are provided in a plurality of columns in the sub scanning direction (Y direction). Group) 4. In the example of FIG. 16, the light emitter block 4 forms two rows of light emitting element lines 3 in which four light emitting elements 2 are arranged in the main scanning direction in the sub scanning direction. In the first row, light-emitting element rows by odd-numbered light-emitting elements are arranged, and in the second row, light-emitting element rows by even-numbered light-emitting elements are arranged.

  The light emitter block 4 is arranged corresponding to the microlens 5. The numbers 1 to 8 of the light emitting elements 2 correspond to the positions of the light emitting elements as viewed from the position A where the microlens 5 is not passed, as described in FIG. Therefore, in FIG. 16, for the sake of convenience, the microlens 5 is displayed with a solid line, but it should be originally displayed with a broken line as shown in FIG. As the light emitting element 2, for example, an organic EL element is used. Since the organic EL element does not need to reduce the diameter of the light emitting part, the light power of the light emitting part can be increased. For this reason, it is possible to use an organic EL material having a low luminous efficiency. The output light of each light emitting element is inverted in the main scanning direction by the microlens 5 and irradiated to the image carrier.

  The output light of each light emitting element 2 is inverted in the main scanning direction and the sub scanning direction by the microlens 5 and irradiated to the image carrier. Such inversion in the sub-scanning direction will be described with reference to FIG. FIG. 17 shows the position of the imaging spot (image formation position) when the output surface of the light emitting element 2 irradiates the exposure surface 7 of the image carrier (photosensitive body) 41 through the microlens 5 with the output light of each light emitting element 2. FIG. In FIG. 17, the microlens 5 has a negative optical magnification. When the output light of the light emitting element is irradiated, the imaging position 7 on the image carrier is the position of the light emitting element in the main scanning direction and the sub scanning direction. The position is reversed.

  That is, in FIG. 17, the imaging spot (image) on the image carrier 7 of the first light emitting element arranged on the upstream side in the moving direction (sub-scanning direction) of the image carrier is downstream in the sub-scanning direction. Formed on the side. Further, the imaging spot on the image carrier 7 of the second light emitting element arranged on the downstream side in the sub scanning direction is formed on the upstream side in the sub scanning direction. In FIG. 17, S is the moving speed of the image carrier, d is the distance in the sub-scanning direction between the light emitting elements, and T1 is the moving time between the predetermined distances of the image carrier, which corresponds to the memory address read timing described later.

  When a plurality of rows of light-emitting element lines 3 are arranged on the microlens 5 as shown in FIG. 16, as described with reference to FIG. Multiple rows are formed in the direction. Thus, when a plurality of rows of light emitting element lines 3 are arranged on the microlens 5, an imaging spot can be formed in a row in the main scanning direction of the image carrier.

  Here, in order to form the imaging spots in a line in the main scanning direction of the image carrier, the light emission timing of the light emitting elements in the first row (odd number) in FIG. 16 and the second row (even number) in FIG. It is necessary to adjust the light emission timing of the light emitting element. In consideration of the reversal of the imaging spot position in the sub-scanning direction, the second row of light emitting elements emits light first, and then the first row of light emitting elements emits light.

  FIG. 15 is an explanatory diagram when forming a row of imaging spots in the main scanning direction. FIG. 15A shows a table 10 of a line buffer memory that stores image data. A pixel number (image data number corresponding to the light emitting element number in FIG. 16) is set on the horizontal axis of the memory table 10, and a column number (imaging spot line formed on the image carrier) is set on the vertical axis. is doing. FIG. 15B shows the position of the imaging spot formed on the image carrier. The number of the imaging spot corresponds to the number of the light emitting element in FIG.

  Of the image data stored in the line buffer memory, the first image data (2, 4, 6, 8) corresponding to the light emitting elements in the second column of the light emitting element group shown in FIG. The device emits light. Next, after time T1, the second image data (1, 3, 5, 7) corresponding to the light emitting elements in the first column stored in the memory address is read and emitted. The output light of the light emitting element is inverted in the main scanning direction by the microlens and irradiated to the image carrier.

  In this way, the first row of imaging spots on the image carrier is formed in the same row as the second row of imaging spots in the main scanning direction. That is, as shown in FIG. 15B, the position of the light emitting element is reversed in the main scanning direction, and the imaging spots 8 arranged in a line on the image carrier are formed. In the pixel numbers set on the horizontal axis of the table of FIG. 15A, the even number of the memory address corresponds to the light emitting element (even number) in the second light emitting element column of FIG. Further, the odd number of the memory address corresponds to the light emitting element (odd number) of the first light emitting element row in FIG.

  When there are a plurality of imaging spot lines formed on the image carrier in the sub-scanning direction, the following processing is performed. For example, the reading procedure when the T1 time corresponds to the time required for the image carrier to move in the sub-scanning direction for one line is as follows. (1) The image data corresponding to the second row of light emitting elements in line 1 is read (even number) and light is emitted. (2) Read out image data corresponding to the first row of light emitting elements in line 1 (odd number), and simultaneously read out image data corresponding to the second row of light emitting elements in line 2 (even number), each emitting light Let (3) The above process 2 is repeated sequentially.

  As described above, when a plurality of light emitting element lines are arranged in the sub-scanning direction with respect to the microlens, the table structure of the memory that stores the image data supplied to each light emitting element is devised. . That is, as shown in FIG. 15A, the memory addresses are divided into even-numbered groups and odd-numbered groups. For example, image data of even-numbered groups is read at a time and transmitted to the corresponding light emitting elements. Next, after a predetermined time has elapsed, the image data of the odd group is simultaneously read and transmitted to the corresponding light emitting elements.

  The even-numbered group and odd-numbered group image data is divided into light-emitting element lines arranged in a plurality of rows in the sub-scanning direction corresponding to the microlenses and transmitted. The arrangement of the image data at the memory address is set in consideration of the fact that the imaging spot on the image carrier by the light emitting element is inverted in the main scanning direction. By setting the configuration of such a memory table and the timing of reading image data from the memory table, when a plurality of light emitting element lines are arranged in the sub-scanning direction corresponding to the microlens, the image carrier The imaging spots can be formed in a line in the main scanning direction. The light emitting element lines corresponding to the microlenses have been described so far as being arranged in two rows in the sub-scanning direction, but a configuration in which three or more light emitting element rows are arranged in the sub-scanning direction may be used.

  The explanatory diagram of FIG. 18 shows the imaging spot 9 on the image carrier when the microlens is poorly adjusted. As shown in FIG. 18, the T1 (movement time of the image carrier between a predetermined distance) due to fluctuations in the speed S of the image carrier, variations in the distance d of the light emitting element in the sub-scanning direction, optical adjustment variations, and the like. ) Is not stable, and even if designed so that T1 corresponds to one line, it varies slightly.

For this reason, the imaging spot formation position in the first row and the imaging spot formation position in the second row are shifted, and the shape of the imaging spot that should be aligned in one row is distorted as shown in FIG. That is, the image quality is degraded. Therefore, a slight misalignment is corrected by adopting a configuration in which T1 can be finely adjusted. T1 can be obtained as follows.
T1 = | (d × β) / S |
Here, each parameter is as follows.
d: Distance in the sub-scanning direction of the light emitting element
S: Moving speed of image plane (image carrier) β: Lens magnification

  So far, an example in which two rows of light emitting element lines made of four light emitting elements in the main scanning direction are arranged in the sub scanning direction with respect to the microlens 5 has been described. In the embodiment of the present invention, a larger number of light emitting element lines can be arranged on the microlens 5. FIG. 19 and FIG. 20 show an example in which four rows of light emitting element lines composed of eight light emitting elements in the main scanning direction are arranged in the sub scanning direction. Reference numeral 41 denotes an image carrier that moves at a speed S in the direction of the arrow. 19 and 20 also, an image spot is formed on the image carrier 41 at a position where the position of the light source is reversed in the main scanning direction and the sub-scanning direction.

  In the embodiment of the present invention, on the premise of the example described in FIGS. 15 to 20, a plurality of microlenses 5 are arranged in the main scanning direction and the sub-scanning direction of the light emitter array using the line head. Further, in each microlens 5, when a plurality of light emitting elements are arranged in a matrix in the main scanning direction and the sub-scanning direction, image data is written in a memory table so that a smooth image can be formed on the image carrier. Is. Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 9, a flowchart of FIG. 10, a memory configuration of FIGS. 11 and 12, and block diagrams of FIGS. 13 and 14.

  FIG. 1 shows an example in which a plurality of microlenses 5 are arranged in the main scanning direction and the sub-scanning direction of the light emitter array 1. In each microlens 5, a light emitter block 4 is formed by arranging four rows of light emitting element lines provided with eight light emitting elements in the main scanning direction in the sub scanning direction. The light emitter block 4 has a plurality of light emitting elements arranged in a matrix.

  FIG. 3 is an explanatory view showing the correspondence with the image carrier 41 by partially cutting the line head vertically. The light emitter array 1 in which a plurality of light emitting elements 2 are arranged in the main scanning direction and the sub scanning direction is attached to the case 70 and fixed to the holder 71 together with the microlens 5. A, B, and C indicate viewpoint positions. In FIG. 1, the viewpoint is at the position B, and the microlens 5 is displayed by a solid line.

  FIG. 2 is an explanatory view showing, in an enlarged manner, light emitting elements arranged corresponding to a single microlens 5 among the plurality of microlenses shown in FIG. In FIG. 2, each light emitting element is numbered 1 to 32. As described above, eight light emitting elements 2 are arranged in the main scanning direction to form light emitting element lines. The light emitting element lines are arranged in four rows in the sub-scanning direction. In this example, the number m of light emitting elements in the main scanning direction is m = 8, and the number of light emitting element lines n in the sub scanning direction is n = 4, and the light emitting elements are arrayed in m × n two-dimensionally on each microlens 5. ing. Thus, in the embodiment of the present invention, the m × n-th light-emitting element of the light-emitting body block (the 32nd in the example of FIG. 2) is arranged on the axial tip side of the light-emitting array and in the axial direction. They are arranged in the first row in the orthogonal direction (upstream in the moving direction of the image carrier). The first light emitting elements of the light emitter block are arranged on the rear end side in the axial direction and in the nth column (downstream in the moving direction of the image carrier) in the direction orthogonal to the axial direction.

  In FIG. 2, the numbers 1 to 32 assigned to the light emitting elements are different from the numbers described in FIG. 16. In FIG. 16, the light emitting element of the upper light emitting element line in the left end of the main scanning direction and the upper light emitting element line in the sub scanning direction is number 1, and the light emitting element of number 2 is arranged at the left end of the lower light emitting element line in the sub scanning direction. . On the other hand, in the example of FIG. 2, the light emitting element of the lower light emitting element line in the right end of the main scanning direction and the lower light emitting element line in the sub scanning direction is number 1, and the number 2 is the right end of the upper light emitting element line in the sub scanning direction. The light emitting element is arranged. This is because FIG. 2 is a diagram viewed from the viewpoint B of FIG. 3, that is, a diagram viewed through the microlens 5, and thus the positions of the light emitting elements appear to be reversed in the main scanning direction and the sub scanning direction.

  4 and 5 show the light emitter array seen from the viewpoint A in FIG. As for the arrangement order of the light emitting elements 1 to 32, the light emitting elements of the light emitting element lines on the upstream side in the sub-scanning direction at the left end in the main scanning direction are numbered as in the example described in FIG. By adopting such an arrangement order of the light emitting elements, consistency with a memory for storing image data is taken, and an imaging spot is smoothly formed on the image carrier. The configuration of the memory will be described later with reference to FIGS.

  FIG. 6 is an explanatory diagram showing a state in which it is assumed that the light emitter array 1 is projected onto the image carrier 41 viewed from the viewpoint C in FIG. FIG. 7 is a partially enlarged view of FIG. The light emitting elements appear to be arranged in the order of numbers 1 to 32 as described in FIG. 5 on the output side of the microlens 5. Therefore, the positions of the image forming spots formed on the image carrier 41 are formed as shown in FIG. 7 with the state of FIG. 5 reversed in the main scanning direction and the sub scanning direction.

  On the image carrier 41, the imaging spots 9 must be formed in one line in the main scanning direction as shown in FIG. When the light emitting elements 1 to 32 are arranged on the microlens 5 of the light emitter array 1 in the order shown in FIG. 2, in the embodiment of the present invention, as shown in FIG. The image data is stored in the memory so that the imaging spots 9 are formed in the order of 1 to 32 in one row. Reference numerals 62 to 64 denote imaging spots formed by light emitting elements arranged corresponding to adjacent microlenses.

  FIG. 10 is a flowchart showing the processing procedure of the present invention. Next, this flowchart will be described. The program is started (S1), and it is determined whether printing is started (S2). If this determination result is No, the process ends. If the determination result is Yes, the controller transmits video data (image data) for one column in the main scanning direction to the control device (S3). Next, video data for one column formed in the main scanning direction of the image carrier is stored in the line buffer memory (S4).

  As shown in FIG. 2, assuming that four rows of light emitting element lines are formed in the sub-scanning direction, only the video data corresponding to the fourth row of light emitting elements is read from the line buffer memory and transmitted to the line head ( S5). Hereinafter, only the video data corresponding to the light emitting elements in the third column to the first column is read from the line buffer memory and transmitted to the line head (S6 to S8). It is determined whether or not printing has been completed (S9). If the determination result is Yes, the process ends. If a determination result is No, it will return to the process of S3 and will repeat the loop process of S3-S9.

  11 and 12 are explanatory diagrams showing an example of the table 10 for storing video data (image data) provided in the line buffer memory. Hereinafter, the memory control will be described. The horizontal pixel number 1 in the table 10 corresponds to the image data at the writing position in the main scanning direction (longitudinal direction) of the image carrier. The column number in the vertical direction of the table 10 corresponds to the number of image data written in the sub-scanning direction (movement direction) of the image carrier. Next, the order of writing and reading of the table 10 will be described. (A) Video data (image data) for one column in the main scanning direction is stored in the line buffer memory. (B) Only video data (4, 8,...) Corresponding to the light emitting elements in the fourth column is read from the line buffer memory.

  (C) After T time, only the video data (3, 7,...) Corresponding to the light emitting elements in the third column is read from the line buffer memory. (D) Further, only video data (2, 6,...) Corresponding to the light emitting elements in the second column is read from the line buffer memory after T time. (E) Further, only video data (1, 5,...) Corresponding to the light emitting elements in the first column is read from the line buffer memory after T time. (F) The next column of video data in the main scanning direction is stored in the line buffer memory. As described above, in the embodiment of the present invention, the control unit converts the image data stored in the memory table into the order of the nth column, the n−1th column,. And the light emitting elements are driven to form one row of images in the axial direction of the image carrier.

  Next, a specific example of memory control as shown in FIGS. 11 and 12 by the control device will be described. In this example, the light emitter block described in FIG. 2 is referred to as a “group”. (A) The light emission timing of each group is determined based on a signal for identifying the group. (B) The image data in the group is counted, and the lines in the group are divided (n columns in the sub-scanning direction, n−1 columns,...) Based on the count value. (3) Inversion of the X axis (main scanning direction) and the Y axis (sub scanning direction) is determined based on the identification signal for identifying the line and the image data count value. (4) The write address of the line buffer memory is determined based on the horizontal synchronization signal (Hsync), the Duloop identification signal and the line identification signal, and the inverting circuit control. (5) The read address of the line buffer memory is determined based on the Hsync signal, the group identification signal and the line identification signal, and the inverting circuit control.

  FIG. 13 and FIG. 14 are block diagrams showing examples of the line head control device of the present invention. In FIG. 13, the controller 30 transmits the image data to the line buffer 23 of the control device 20 as described in FIG. Image data (video data) stored in the line buffer 23 is sequentially read from the data in the fourth column in the sub-scanning direction, and transmitted to the line head 101 provided in the printer 31.

  The control device 20 includes a counter 31 that counts image data in the light emitter blocks (groups) formed in the sub-scanning direction, a group detector 32 that detects the light emitter blocks, and an inversion circuit that inverts the image in units of light emitter blocks. 36, an inter-group timing controller 34 for controlling the light emission timing between the light emitter blocks, a column detector (not shown) for detecting the number of columns in the light emitting element group (light emitter block), and between the columns in the light emitter block It comprises a line timing controller (not shown) for controlling the light emission timing, a line buffer memory 23 for storing image data for the above timing, a horizontal sync signal (Hsync) generator 35, and an adder 37.

  The operation of the control device 20 will be described. (A) Group detection is performed based on a group detection signal sent from the controller 30. (B) Based on the counter value for counting the pixel unit of the image data of the counter 31, a Durrup detection signal is generated. (C) The inversion circuit 36 performs inversion processing of the light emitter block based on the group identification signal. (D) The reversing circuit 36 performs reversal processing of both the X axis (main scanning direction) and the Y axis (sub scanning direction). (E) The light emission timing of the light emitting element group is determined based on the group identification signal and the Hsync signal. (F) The light emission timings of the remaining light emitting element groups are determined based on the light emission timings of the first light emitting element group. (G) The light emission timing adjustment between the light emitting element groups is performed at a frequency higher than that of the image data clock.

  FIG. 14 is a block diagram illustrating the writing module P and the reading module Q of the control device 20 described in FIG. FIG. 14 shows a controller 30 for transmitting video data, a write module P for controlling the write address, a read module Q for controlling the read address, a Read / Write timing adjustment module 38 for controlling the overall write / read timing, and video data. A line buffer memory 23 for storing is shown.

  The write module P includes a write address counter 31a driven by a video clock, a pointer counter 31b driven by Hsync, and an adder 37a. Based on the count values of these counters 31 a and 31 b, the video data from the controller 30 is written at a predetermined address in the line buffer memory 23.

  Next, the read module Q detects the group and controls the inversion for each group by detecting the group by the read address counter 31 and the group detector 32 for controlling the offset amount between groups (between the light emitter blocks) based on the counter value of the read video clock And an odd / even detector 39 for controlling the detection of odd and even elements, a boundary detector 40 for controlling the boundary data at the end of the image by counting the readout video clock and Hsync, and an adder 37b. ing.

  The adder 37b controls the entire read timing based on the output signal of the group detector 32, the inverting circuit 36, the odd / even detector 39, and the Hsync counter value of the pointer counter 31b. When image data is stored in the line buffer memory 23, the light emission timing for each group may be adjusted to invert the image. In addition, the timing of light emission can be adjusted more precisely by adjusting the light emission timing for each group more finely than the video clock. Furthermore, when performing line head tilt correction, the algorithm does not become complicated if the light emission timing for each group is adjusted and the image is inverted before tilt correction.

  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. 21 is a longitudinal side view showing an example of a tandem image forming apparatus using an organic EL element as a light emitting element. This image forming apparatus includes four light emitter arrays (line heads) 101K, 101C, 101M, and 101Y having the same configuration and four corresponding photosensitive drums (image carriers) 41K and 41C having the same configuration. , 41M and 41Y, respectively, and is configured as a tandem image forming apparatus.

  As shown in FIG. 21, this image forming apparatus is provided with a driving roller 51, a driven roller 52, and a tension roller 53, and is tensioned by the tension roller 53 and stretched in the direction indicated by the arrow (counterclockwise). ) Is circulated to the intermediate transfer belt (intermediate transfer medium) 50. Photosensitive members 41K, 41C, 41M, and 41Y having photosensitive layers are arranged on the outer peripheral surface as four image carriers 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, and indicate that the photoconductors are black, cyan, magenta, and yellow, respectively. The same applies to other members. The photoreceptors 41K, 41C, 41M, and 41Y are rotationally driven 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 (corona charger) 42 (K) for uniformly charging the outer peripheral surface of the photoconductor 41 (K, C, M, Y), respectively. , C, M, Y) and the outer peripheral surface uniformly charged by the charging means 42 (K, C, M, Y) are synchronized with the rotation of the photoconductor 41 (K, C, M, Y). Thus, the above-described light emitter array (line head) 101 (K, C, M, Y) of the present invention for sequentially scanning the line is provided.

  Further, a developing device 44 that applies toner as a developer to the electrostatic latent image formed by the light emitter array (line head) 101 (K, C, M, Y) to form a visible image (toner image). (K, C, M, Y) and primary transfer as transfer means for sequentially transferring the toner image developed by the developing device 44 (K, C, M, Y) to the intermediate transfer belt 50 as a primary transfer target. A roller 45 (K, C, M, Y) and a cleaning device 46 (K, C) as a cleaning means for removing toner remaining on the surface of the photoconductor 41 (K, C, M, Y) after being transferred. C, M, Y).

  Here, in each light emitter array (line head) 101 (K, C, M, Y), the array direction of the light emitter array exposure head 101 (K, C, M, Y) is the photosensitive drum 41 (K, C). , M, Y) along the bus. Then, the emission energy peak wavelength of each light emitter array (line head) 101 (K, C, M, Y) and the sensitivity peak wavelength of the photoconductor 41 (K, C, M, Y) are substantially matched. Is set.

  The developing device 44 (K, C, M, Y) uses, for example, a non-magnetic one-component toner as a developer, and the one-component developer is conveyed to the developing roller by a supply roller, for example, and adhered to the developing roller surface. The film thickness of the developed developer is regulated by a regulating blade, and the developing roller is brought into contact with or increased in thickness by the photosensitive body 41 (K, C, M, Y), whereby the photosensitive body 41 (K, C, M, Y). The toner is developed as a toner image by attaching a developer according to the potential level.

  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.

  In FIG. 21, reference numeral 63 denotes a paper feed cassette in which a large number of recording media P are stacked and held, 64 denotes a pickup roller for feeding the recording media P one by one from the paper feed cassette 63, and 67 denotes a secondary transfer roller. Reference numeral 69 denotes a gate roller pair that regulates the supply timing of the recording medium P to the secondary transfer portion 66, and 69 denotes a cleaning blade as a cleaning means for removing toner remaining on the surface of the intermediate transfer belt 50 after the secondary transfer. .

  As described above, the image forming apparatus and the image forming method of the present invention have been described based on the principle and the embodiments, but the present invention is not limited to these embodiments and can be variously modified.

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 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 explanatory drawing which shows embodiment of this invention. It is a flowchart which shows the process sequence 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 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. 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 schematic cross-sectional view showing an overall configuration of an embodiment of an image forming apparatus using an electrophotographic process of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Light emitter array, 2 ... Light emitting element, 3 ... Light emitting element row, 4 ... Light emitter block (light emitting element group), 5 ... Micro lens, 7 ... Imaging position 8, 9 ... Imaging spot, 10 ... Table, 20 ... Control device, 23 ... Line buffer memory, 30 ... Controller, 31 ... Printer, 41 (K, C, M, Y) ... photosensitive drum (image carrier), 42 (K, C, M, Y) ... charging means (corona charger), 44 (K, C, M, Y) ... Developing device, 45 (K, C, M, Y) ... primary transfer roller, 50 ... intermediate transfer belt, 66 ... secondary transfer roller, 70 ... case, 71 ... holder, 101K , 101C, 101M, 101Y... Light emitter array (line head)

Claims (13)

A lens having a negative optical magnification and a line head provided with a light emitter array in which a plurality of light emitting elements are arranged, and the lens is in a direction orthogonal to the axial direction (main scanning direction) of the image carrier (the axial direction) A plurality of light emitting element lines each having m light emitting elements arranged in the main scanning direction are arranged in n rows in the sub scanning direction. An image forming apparatus comprising: a control unit configured to associate a light emitter block, drive each light emitting element by inverting it in the axial direction and a direction orthogonal to the axial direction, and form an image on the image carrier. . The control means forms a row of images in the axial direction of the image carrier with the output light of m × n light emitting elements provided corresponding to the lenses arranged in the axial direction. The image forming apparatus according to claim 1. The control means uses the output light of m × n light emitting elements provided corresponding to the axial direction and the lenses arranged in a direction perpendicular to the axial direction, in a line in the axial direction of the image carrier. The image forming apparatus according to claim 1, wherein the formed images are formed in a plurality of rows in a direction orthogonal to the axial direction. The m × n-th light emitting elements of the light emitter block corresponding to the respective lenses are arranged in a first column on the tip end side in the axial direction of the light emitter array and in a direction perpendicular to the axial direction. 2. The image forming apparatus according to claim 1, wherein the first light emitting elements are arranged in an n-th column on the rear end side in the axial direction and in a direction orthogonal to the axial direction. Storage means for storing image data to be supplied to each of the light emitting elements is provided, and the storage means stores image data so that images are sequentially formed in a line along the axial direction from the axial writing position of the image carrier. The image forming apparatus according to claim 1, wherein: The storage means sequentially forms image data in one column along the axial direction from the axial writing position of the image carrier, and image data so that a plurality of images are formed in a direction orthogonal to the axial direction. The image forming apparatus according to claim 1, wherein: The control means reads out the image data stored in the storage means in the order of the n-th column, the n−1th column,..., The first column of each light-emitting body block, and drives each light-emitting element. The image forming apparatus according to claim 5, wherein the image forming apparatus is characterized. The image forming apparatus according to claim 1, wherein a plurality of line heads are provided corresponding to each color, and image formation of a plurality of colors is performed simultaneously on the image carrier. The image forming apparatus according to claim 1, wherein the light emitting element is an organic EL element. At least two image forming stations in which image forming units including a charging unit, a line head according to any one of claims 1 to 9, a developing unit, and a transfer unit are arranged around an image carrier. An image forming apparatus provided as described above, wherein the transfer medium passes through each station and forms an image by a tandem method. The image forming apparatus according to claim 10, further comprising an intermediate transfer member. A plurality of lenses having a negative optical magnification and arranged in an axial direction (main scanning direction) of the image carrier and a direction orthogonal to the axial direction (sub-scanning direction), and m lenses in the main scanning direction. A plurality of line heads each having a light emitter array corresponding to a light emitter block made up of m × n light emitting elements in which n rows of light emitting element lines arranged in the sub-scanning direction are arranged corresponding to each color,
Image data is formed so that images are sequentially formed in one column along the axial direction from the axial writing position of the image carrier on the storage means, and a plurality of images are formed in a direction orthogonal to the axial direction. Storing the data, reading the image data stored in the storage means, driving the light emitting elements in the axial direction and in the direction orthogonal to the axial direction by driving the read image data, And an image forming method comprising: simultaneously performing image formation of a plurality of colors on the image carrier. The image forming method according to claim 12, wherein the image data is read in the order of the n-th column, the n−1th column,.

Images