JP2009149051A - Line head and image forming apparatus using this line head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique which can easily lead out wirings from a light emitting element to one direction side and which can simplify the manufacturing process of a line head and which can suppress the manufacturing cost of the line head. <P>SOLUTION: An image forming apparatus has a head substrate, a first light emitting element group arranged on the head substrate and having a first light emitting element and a second light emitting element, a second light emitting element group and a third light emitting element group arranged in the first direction of the head substrate, first wirings arranged between the second light emitting element group and the third light emitting element group of the head substrate and electrically connected to the first light emitting element, second wirings arranged between the second light emitting element group of the head substrate and the third light emitting element group of the head substrate, and electrically connected to the second light emitting element, and a connector electrically connected to the first wirings and the second wirings. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a line head that forms an image of a light beam emitted from a light emitting element with a lens, and an image forming apparatus using the line head.

  In such a line head, for example, as described in Patent Document 1, a plurality of light emitting elements arranged in the longitudinal direction (X direction in the same document) are arranged in two rows and in a staggered manner (refer to the same document). FIG. 3 etc.). These light emitting elements are formed on the head substrate, and the light emitting operation of each light emitting element is controlled by a controller outside the head substrate. The control of the light emitting element by the controller outside the head substrate can be realized by using a connection member such as a flexible printed circuit board called a so-called FPC (Flexible printed circuits).

  That is, one end of the FPC is attached to the head substrate, and the other end of the FPC is pulled out of the head substrate. One end of the FPC is connected to a wiring drawn from each light emitting element. Therefore, when a light emission control signal is input from the controller to the other end of the FPC, the light emitting element emits a light beam based on the light emission control signal. In this manner, the light emission of the light emitting element can be controlled by the external controller. The light beam from the light emitting element is imaged by a gradient index rod lens array to form a latent image on the surface of a latent image carrier such as a photoconductor.

JP 2007-290303 A

  By the way, in the above-described configuration, it may be difficult to draw out the wiring connected to the light emitting element only to one side of the head substrate. In other words, in the above configuration, a plurality of light emitting elements arranged in the longitudinal direction (X direction in the same document) are arranged in two rows and zigzag, and it may be difficult to pass wiring between the light emitting elements. . Furthermore, in order to perform the latent image forming operation with higher resolution, when the interval between the light emitting elements is narrowed, it is even more difficult to pass the wiring between the light emitting elements. As a result, in the line head as described above, it may be necessary to draw out wiring on both sides of the light emitting element in the width direction. More specifically, a wiring is drawn out from one row of light emitting elements to one side in the width direction, and a wiring is drawn out from the other row of light emitting elements to the other side in the width direction so that the wiring does not pass between the light emitting elements. It may be necessary to do so. Here, the width direction is a direction orthogonal or substantially orthogonal to the longitudinal direction.

  When wirings are drawn out on both sides in this way, FPCs connected to these wirings are also attached to both sides of the head substrate. However, from the viewpoint of simplifying the manufacturing process of the line head and suppressing the manufacturing cost, it is desirable that the member such as the FPC is attached only to one direction side of the head substrate. This is because in such a configuration, it is sufficient to perform a process for attaching a member such as an FPC only on one side of the head substrate.

  The present invention has been made in view of the above problems, and provides a technique that enables the wiring to be easily drawn out from the light emitting element in one direction, thereby simplifying the manufacturing process of the line head and suppressing the manufacturing cost. With the goal.

  In order to achieve the above object, a line head according to the present invention includes a head substrate, a first light emitting element group disposed on the head substrate and having a first light emitting element and a second light emitting element, and a first of the head substrate. The second light emitting element group and the third light emitting element group disposed in the direction, and the second light emitting element group and the third light emitting element group of the head substrate are disposed between the first light emitting element and the first light emitting element. A first wiring connected to the second light emitting element group, a second wiring electrically connected to the second light emitting element, the second wiring disposed between the second light emitting element group and the third light emitting element group of the head substrate, and the head It is characterized by having a connection portion which is disposed on the substrate and is electrically connected to the first wiring and the second wiring.

  In order to achieve the above object, an image forming apparatus according to the present invention includes a head substrate, a first light emitting element group disposed on the head substrate and having a first light emitting element and a second light emitting element, and a head substrate. The second light emitting element group and the third light emitting element group disposed in the first direction of the head substrate, and the first light emitting element disposed between the second light emitting element group and the third light emitting element group of the head substrate. A first wiring electrically connected to the second light emitting element group, and a second wiring electrically disposed between the second light emitting element group and the third light emitting element group of the head substrate. And a connection portion disposed on the head substrate and electrically connected to the first wiring and the second wiring, and a controller that outputs a light emission control signal for controlling light emission of the light emitting element. Yes.

  According to the thus configured invention (line head, image forming apparatus), the first light emitting element group having the first light emitting element and the second light emitting element, and the second light emitting element group disposed in the first direction. The third light emitting element group is disposed on the head substrate. The head substrate includes a first wiring electrically connected to the first light emitting element, a second wiring electrically connected to the second light emitting element, the first wiring, and the second wiring. And a connecting portion to be connected to each other. Here, the first wiring and the second wiring are disposed between the second light emitting element group and the third light emitting element group. Therefore, it is possible to electrically connect the first wiring and the second wiring to the connecting portion by effectively using the space between the second light emitting element group and the third light emitting element group. As a result, it is possible to reduce the size of the head substrate, thereby reducing the manufacturing cost of the line head.

  The first light emitting element group includes a first light emitting element row having a light emitting element including the first light emitting element disposed in the first direction, and a light emitting element including the second light emitting element disposed in the first direction. And the second light emitting element row may be disposed so as to be located closer to the connection portion than the first light emitting element row.

  In addition, the fourth light emitting element group may be arranged in the first direction of the first light emitting element group, and the first wiring may be arranged between the first light emitting element group and the fourth light emitting element group. . If comprised in this way, between the 1st light emitting element group and the 4th light emitting element group can be utilized effectively, and a 1st wiring can be electrically connected with a connection part suitably. Here, the first wiring may be wired on the side opposite to the side on which the connection portion is arranged and electrically connected to the connection portion. According to this configuration, it is possible to reliably avoid the first wiring passing between the light emitting elements belonging to the second light emitting element row. Accordingly, the interval between the light emitting elements can be shortened.

  The first light emitting element group has a third light emitting element row disposed so as to be positioned closer to the connection portion than the second light emitting element row, and the second wiring is a light emitting element of the third light emitting element row. It may be arranged between them. According to this configuration, since only the second wiring is disposed between the light emitting elements in the third light emitting element row, an increase in the interval between the light emitting elements in the third light emitting element row can be minimized.

  The first light emitting element group includes a fourth light emitting element row disposed so as to be positioned on the side opposite to the connection portion from the first light emitting element row, and the first wiring emits light from the fourth light emitting element row. It may be arranged between the elements. According to this configuration, since only the first wiring is disposed between the light emitting elements in the fourth light emitting element row, an increase in the interval between the light emitting elements in the fourth light emitting element row can be minimized.

  Further, a connection circuit that is electrically connected to the connection portion of the head substrate may be provided. According to this configuration, electrical connection with the outside of the head substrate can be easily performed via the connection circuit. Further, an electric circuit is provided which is electrically connected to the connection portion of the head substrate through or without the connection circuit and outputs a drive signal for driving the light emitting element based on the input light emission control signal. May be. Here, the electric circuit may be interposed between the connection part of the head substrate and the connection circuit. According to this configuration, the electric circuit can be disposed relatively close to the light emitting element. Therefore, it is possible to supply a driving signal with less dullness due to stray capacitance or the like to the light emitting element.

  Further, the electric circuit may be provided in the connection circuit. According to this configuration, since the electric circuit is not disposed on the head substrate, the area of the head substrate can be reduced. The electric circuit may be provided with a driving substrate, and the electric circuit may be electrically connected to the connection portion of the head substrate via the connection circuit. According to this configuration, since the electric circuit is provided on the driving substrate different from the head substrate, the degree of freedom in designing the electric circuit can be increased. Further, the connection portion of the head substrate may be configured such that the first wiring and the second wiring are gathered at one place in the first direction. According to this configuration, the connection portion can be reduced in size, and the connection configuration with the outside of the head substrate can be simplified.

  In order to achieve the above object, a line head according to another aspect of the present invention includes a plurality of light emitting elements grouped for each light emitting element group, and wiring connected to the light emitting elements. A head substrate in which a plurality of light emitting element group rows in which a plurality of groups are arranged in the first direction are provided in a second direction orthogonal or substantially orthogonal to the first direction, and one region on one side of the light emitting element group in the second direction of the head substrate A connecting member having one end attached to the head substrate and the other end drawn to the outside of the head substrate. In the light emitting element group row, a plurality of light emitting element groups are arranged with a space therebetween. The respective light emitting element group rows are shifted from each other in the first direction so that the positions of the respective light emitting element groups are different from each other in the direction, and each wiring is drawn out to one region In both cases, the wiring drawn from one light emitting element group row to the other region beyond the other light emitting element group row is drawn through the space of the other light emitting element group row, and one end of the connecting member is electrically connected to the wiring. The connection member is connected via a circuit or not, and the other end of the connection member can input a signal related to a light emission control signal output by a controller outside the head substrate.

  In order to achieve the above object, an image forming apparatus according to another aspect of the present invention includes a plurality of light emitting elements grouped for each light emitting element group, and wiring connected to the light emitting elements. A head substrate having a plurality of light emitting element group rows arranged in a first direction in a second direction orthogonal to or substantially orthogonal to the first direction, and one side of the head substrate in the second direction from the light emitting element group A line head having a connecting member having one end attached to one region of the head and a second end drawn to the outside of the head substrate, and a light emission control signal for controlling light emission of the light emitting element of the line head. In the light emitting element group row, a plurality of light emitting element groups are arranged with a space therebetween, and in the head substrate, each light emitting element group is arranged in the first direction. The respective light emitting element group rows are shifted from each other in the first direction so that the positions are different from each other, and each wiring is drawn out to one area and from one light emitting element group line to the other light emitting element group line. The wiring drawn out to the other light emitting element group row is drawn out, and one end of the connecting member is connected to the wiring through or without an electric circuit, and the other end of the connecting member Is characterized in that it can input a signal related to the light emission control signal output from the controller.

  In the invention thus configured (line head, image forming apparatus), a plurality of light emitting elements grouped for each light emitting element group and wirings connected to the light emitting elements are provided on the head substrate. In this head substrate, a plurality of light emitting element group rows in which a plurality of light emitting element groups are arranged in the first direction are provided in a second direction orthogonal or substantially orthogonal to the first direction. In the light emitting element group row, the plurality of light emitting element groups are arranged with a space therebetween. In addition, the light emitting element group rows are shifted from each other in the first direction so that the positions of the light emitting element groups are different from each other in the first direction. Therefore, a wiring that is drawn out from one light emitting element group row to one region beyond the other light emitting element group row is drawn through the space of the other light emitting element group row, so that the wiring is easily drawn out to one region. It is possible. Here, the “one region” is a region on one side of the light emitting element group in the second direction of the head substrate. Therefore, the connecting member connected to the wiring via the electric circuit or not can be provided in this one region, and the manufacturing process of the line head can be simplified and the manufacturing cost can be suppressed.

  In addition, a driver IC that converts the light emission control signal into a signal for driving the light emitting element is provided on the head substrate as the electric circuit, and one end of the connection member is connected to the wiring via the driver IC, and You may comprise so that a light emission control signal may be input into an other end part. In such a configuration, the driver IC can be disposed relatively close to the light emitting element. Therefore, it is possible to supply a driving signal with less dullness due to stray capacitance or the like to the light emitting element.

  In addition, a driver IC that converts the light emission control signal into a drive signal for driving the light emitting element is provided on a driver IC substrate different from the head substrate, and one end of the connection member is connected to the wiring, The end portion may be connected to the driver IC so that a drive signal is input from the driver IC. In such a configuration, the driver IC is provided on a drive substrate different from the head substrate. Therefore, the driver IC can be relatively freely arranged and laid out, and the cost of the driver IC can be suppressed.

  In addition, a driver IC that converts the light emission control signal into a drive signal for driving the light emitting element is provided between one end and the other end of the connection member, and one end of the connection member is connected to the wiring, A light emission control signal is input to the other end of the connection member, and the light emission control signal input to the other end is converted into a drive signal by a driver IC, and the drive signal is output from one end. May be. In such a configuration, since it is not necessary to provide a driver IC on the substrate, the substrate can be made small, and the line head can be configured compactly.

  In addition, the respective wirings may be drawn together at one place in the first direction, and one end of the connection member may be connected to each wiring. When configured in this way, one connecting member may be attached to the substrate, and the process of attaching the connecting member is only required once, so that the manufacturing cost can be suppressed.

  Each light emitting element may be configured to be driven in a time-sharing manner. When configured in this manner, the number of driver ICs can be reduced, and the manufacturing cost can be suppressed.

A. Explanation of Terms Before explaining embodiments of the present invention, terms used in this specification will be explained.

  1 and 2 are explanatory diagrams of terms used in this specification. Here, the terms used in this specification will be organized using these drawings. In this specification, the transport direction of the surface (image surface IP) of the photosensitive drum 21 is defined as a sub-scanning direction SD, and a direction orthogonal or substantially orthogonal to the sub-scanning direction SD is defined as a main scanning direction MD. . The line head 29 is arranged with respect to the surface (image surface IP) of the photosensitive drum 21 so that the longitudinal direction LGD corresponds to the main scanning direction MD and the width direction LTD corresponds to the sub-scanning direction SD. Has been.

  A set of a plurality of (eight in FIG. 1 and FIG. 2) light emitting elements 2951 arranged on the head substrate 293 in a one-to-one correspondence with the plurality of lenses LS included in the lens array 299 is defined as a light emitting element group 295. To do. That is, in the head substrate 293, the light emitting element group 295 including the plurality of light emitting elements 2951 is disposed for each of the plurality of lenses LS. Further, the light beam from the light emitting element group 295 is imaged toward the image plane IP by the lens LS corresponding to the light emitting element group 295, whereby a set of a plurality of spots SP formed on the image plane IP is obtained. It is defined as group SG. That is, the plurality of spot groups SG can be formed in one-to-one correspondence with the plurality of light emitting element groups 295. In each spot group SG, the most upstream spot in the main scanning direction MD and the sub-scanning direction SD is particularly defined as the first spot. The light emitting element 2951 corresponding to the first spot is particularly defined as the first light emitting element.

  Further, as shown in the column “on image plane” in FIG. 2, a spot group row SGR and a spot group column SGC are defined. That is, a plurality of spot groups SG arranged in the main scanning direction MD are defined as spot group rows SGR. The plurality of spot group rows SGR are arranged side by side in the sub-scanning direction SD at a predetermined spot group row pitch Psgr. A plurality (three in the figure) of spot groups SG arranged at the spot group row pitch Psgr in the sub-scanning direction SD and at the spot group pitch Psg in the main scanning direction MD are defined as a spot group column SGC. The spot group row pitch Psgr is a distance in the sub-scanning direction SD between the geometric centroids of two spot group rows SGR adjacent to each other in the sub-scanning direction SD. The spot group pitch Psg is the distance in the main scanning direction MD of the geometric centroids of two spot groups SG adjacent to each other in the main scanning direction MD.

  Lens rows LSR and lens columns LSC are defined as shown in the “lens array” column of FIG. That is, a plurality of lenses LS arranged in the longitudinal direction LGD are defined as a lens row LSR. The plurality of lens rows LSR are arranged side by side in the width direction LTD at a predetermined lens row pitch Plsr. A plurality (three in the figure) of lenses LS arranged at the lens row pitch Plsr in the width direction LTD and at the lens pitch Pls in the longitudinal direction LGD are defined as a lens row LSC. The lens row pitch Plsr is a distance in the width direction LTD of the geometric centroids of two lens rows LSR adjacent to each other in the width direction LTD. The lens pitch Pls is a distance in the longitudinal direction LGD between the geometric centroids of the two lenses LS adjacent to each other in the longitudinal direction LGD.

  As shown in the column “Head Substrate” in the drawing, a light emitting element group row 295R and a light emitting element group column 295C are defined. That is, a plurality of light emitting element groups 295 arranged in the longitudinal direction LGD is defined as a light emitting element group row 295R. The plurality of light emitting element group rows 295R are arranged side by side in the width direction LTD at a predetermined light emitting element group row pitch Pegr. In addition, a plurality of (three in the figure) light emitting element groups 295 arranged at the light emitting element group row pitch Pegr in the width direction LTD and at the light emitting element group pitch Peg in the longitudinal direction LGD are defined as a light emitting element group column 295C. The light emitting element group row pitch Pegr is a distance in the width direction LTD between the geometric centroids of two light emitting element group rows 295R adjacent to each other in the width direction LTD. The light emitting element group pitch Peg is the distance in the longitudinal direction LGD between the geometric centers of gravity of two light emitting element groups 295 adjacent to each other in the longitudinal direction LGD.

  As shown in the “light emitting element group” column of FIG. 2, a light emitting element row 2951R and a light emitting element column 2951C are defined. That is, in each light emitting element group 295, a plurality of light emitting elements 2951 arranged in the longitudinal direction LGD is defined as a light emitting element row 2951R. The plurality of light emitting element rows 2951R are arranged side by side in the width direction LTD at a predetermined light emitting element row pitch Pelr. A plurality of (two in the figure) light emitting elements 2951 arranged in the width direction LTD at the light emitting element row pitch Pelr and at the longitudinal direction LGD in the longitudinal direction LGD are defined as a light emitting element row 2951C. The light emitting element row pitch Pelr is a distance in the width direction LTD of the geometric centroids of two light emitting element rows 2951R adjacent to each other in the width direction LTD. The light emitting element pitch Pel is a distance in the longitudinal direction LGD between the geometric centroids of two light emitting elements 2951 adjacent to each other in the longitudinal direction LGD.

  As shown in the column “Spot Group” in the figure, a spot row SPR and a spot column SPC are defined. That is, in each spot group SG, a plurality of spots SP arranged in the longitudinal direction LGD are defined as spot rows SPR. The plurality of spot rows SPR are arranged side by side in the width direction LTD at a predetermined spot row pitch Pspr. Further, a plurality of (two in the figure) spots arranged at the spot pitch Pspr in the width direction LTD and at the spot pitch Psp in the longitudinal direction LGD are defined as a spot row SPC. The spot row pitch Pspr is a distance in the sub-scanning direction SD between the geometric centroids of two spot rows SPR adjacent to each other in the sub-scanning direction SD. The spot pitch Psp is a distance in the longitudinal direction LGD between the geometric centroids of two spots SP adjacent to each other in the main scanning direction MD.

B. First Embodiment FIG. 3 is a diagram showing an example of an image forming apparatus according to the present invention. FIG. 4 is a diagram showing an electrical configuration of the image forming apparatus of FIG. This apparatus uses a color mode in which four color toners of black (K), cyan (C), magenta (M), and yellow (Y) are superimposed to form a color image, and only black (K) toner. Thus, the image forming apparatus can selectively execute a monochrome mode for forming a monochrome image. FIG. 3 is a diagram corresponding to the execution of the color mode. In this image forming apparatus, when an image forming command is given from an external device such as a host computer to a main controller MC having a CPU, a memory, etc., the main controller MC gives a control signal to the engine controller EC and also outputs an image forming command. Corresponding video data VD is supplied to the head controller HC. The head controller HC controls the line head 29 for each color based on the video data VD from the main controller MC, the vertical synchronization signal Vsync from the engine controller EC, and parameter values. As a result, the engine unit EG executes a predetermined image forming operation, and forms an image corresponding to the image forming command on a sheet such as copy paper, transfer paper, paper, and an OHP transparent sheet.

  An electrical component box 5 containing a power circuit board, a main controller MC, an engine controller EC, and a head controller HC is provided in the housing main body 3 of the image forming apparatus. An image forming unit 7, a transfer belt unit 8, and a paper feed unit 11 are also disposed in the housing body 3. In FIG. 3, a secondary transfer unit 12, a fixing unit 13, and a sheet guide member 15 are disposed on the right side in the housing body 3. The paper feeding unit 11 is configured to be detachable from the apparatus main body 1. The paper feed unit 11 and the transfer belt unit 8 can be removed and repaired or exchanged.

  The image forming unit 7 includes four image forming stations Y (for yellow), M (for magenta), C (for cyan), and K (for black) that form a plurality of images of different colors. Each of the image forming stations Y, M, C, and K is provided with a cylindrical photosensitive drum 21 having a surface with a predetermined length in the main scanning direction MD. Each of the image forming stations Y, M, C, and K forms a corresponding color toner image on the surface of the photosensitive drum 21. The photosensitive drum is arranged so that the axial direction is substantially parallel to the main scanning direction MD. Each photosensitive drum 21 is connected to a dedicated drive motor and is driven to rotate at a predetermined speed in the direction of arrow D21 in the figure. As a result, the surface of the photosensitive drum 21 is conveyed in the sub-scanning direction SD that is orthogonal or substantially orthogonal to the main scanning direction MD. A charging unit 23, a line head 29, a developing unit 25, and a photoconductor cleaner 27 are disposed around the photoconductive drum 21 along the rotation direction. Then, a charging operation, a latent image forming operation, and a toner developing operation are executed by these functional units. Therefore, when the color mode is executed, the toner images formed at all the image forming stations Y, M, C, and K are superimposed on the transfer belt 81 of the transfer belt unit 8 to form a color image, and the monochrome mode is executed. In some cases, a monochrome image is formed using only the toner image formed at the image forming station K. In FIG. 3, the image forming stations of the image forming unit 7 have the same configuration, and therefore, for convenience of illustration, only some image forming stations are denoted by reference numerals, and the other image forming stations are omitted. .

  The charging unit 23 includes a charging roller whose surface is made of elastic rubber. The charging roller is configured to rotate in contact with the surface of the photosensitive drum 21 at the charging position, and at a peripheral speed in the driven direction with respect to the photosensitive drum 21 as the photosensitive drum 21 rotates. Followed rotation. The charging roller is connected to a charging bias generator (not shown). The charging roller is supplied with the charging bias from the charging bias generator and is charged at the charging position where the charging unit 23 and the photosensitive drum 21 come into contact with each other. The surface of 21 is charged.

  The line head 29 is disposed with respect to the photosensitive drum 21 such that the longitudinal direction thereof corresponds to the main scanning direction MD and the width direction thereof corresponds to the sub-scanning direction SD. Is substantially parallel to the main scanning direction MD. The line head 29 includes a plurality of light emitting elements arranged side by side in the longitudinal direction, and is spaced apart from the photosensitive drum 21. Then, light is emitted from these light emitting elements to the surface of the photosensitive drum 21 charged by the charging unit 23, and an electrostatic latent image is formed on the surface.

  The developing unit 25 has a developing roller 251 on which toner is carried. The charged toner is developed at a developing position where the developing roller 251 and the photosensitive drum 21 come into contact with each other by a developing bias applied to the developing roller 251 from a developing bias generator (not shown) electrically connected to the developing roller 251. Is moved from the developing roller 251 to the photosensitive drum 21, and the electrostatic latent image formed by the line head 29 becomes obvious.

  The toner image that has been made visible at the developing position in this way is conveyed in the rotational direction D21 of the photosensitive drum 21, and then a primary transfer position TR1 at which each of the photosensitive drums 21 comes into contact with the transfer belt 81, which will be described in detail later. 1 is primarily transferred to the transfer belt 81.

  In this embodiment, the photosensitive drum cleaner 27 is provided in contact with the surface of the photosensitive drum 21 on the downstream side of the primary transfer position TR1 in the rotational direction D21 of the photosensitive drum 21 and on the upstream side of the charging unit 23. It has been. The photoconductor cleaner 27 abuts on the surface of the photoconductor drum to clean and remove toner remaining on the surface of the photoconductor drum 21 after the primary transfer.

  The transfer belt unit 8 includes a driving roller 82, a driven roller 83 (blade facing roller) disposed on the left side of the driving roller 82 in FIG. 3, and a stretched direction of these rollers in the direction of the arrow D81 (conveying direction). And a transfer belt 81 that is driven to circulate. Further, the transfer belt unit 8 is disposed on the inner side of the transfer belt 81 so as to be opposed to each of the photosensitive drums 21 included in the image forming stations Y, M, C, and K when the photosensitive cartridge is mounted. Four primary transfer rollers 85Y, 85M, 85C, and 85K are provided. Each of these primary transfer rollers 85 is electrically connected to a primary transfer bias generator (not shown). As will be described in detail later, when the color mode is executed, as shown in FIG. 3, all the primary transfer rollers 85Y, 85M, 85C, 85K are positioned on the image forming stations Y, M, C, K side. Then, the transfer belt 81 is pushed and brought into contact with the photosensitive drums 21 included in the image forming stations Y, M, C, and K, so that the primary transfer position TR1 is set between each photosensitive drum 21 and the transfer belt 81. Form. Then, by applying a primary transfer bias from the primary transfer bias generator to the primary transfer roller 85 at an appropriate timing, the toner images formed on the surfaces of the photosensitive drums 21 correspond respectively. A color image is formed by transferring to the surface of the transfer belt 81 at the primary transfer position TR1.

  On the other hand, when the monochrome mode is executed, among the four primary transfer rollers 85, the color primary transfer rollers 85Y, 85M, and 85C are separated from the image forming stations Y, M, and C facing each other, and the monochrome primary transfer is performed. By bringing only the roller 85K into contact with the image forming station K, only the monochrome image forming station K is brought into contact with the transfer belt 81. As a result, the primary transfer position TR1 is formed only between the monochrome primary transfer roller 85K and the image forming station K. Then, by applying a primary transfer bias from the primary transfer bias generator to the monochrome primary transfer roller 85K at an appropriate timing, the toner image formed on the surface of each photosensitive drum 21 is subjected to primary transfer. A monochrome image is formed by transferring to the surface of the transfer belt 81 at a position TR1.

  Further, the transfer belt unit 8 includes a downstream guide roller 86 disposed on the downstream side of the monochrome primary transfer roller 85K and on the upstream side of the driving roller 82. Further, the downstream guide roller 86 is formed between the primary transfer roller 85K and the photosensitive drum 21 at the primary transfer position TR1 formed by the monochrome primary transfer roller 85K contacting the photosensitive drum 21 of the image forming station K. It is configured to contact the transfer belt 81 on a common inscribed line.

  The driving roller 82 circulates and drives the transfer belt 81 in the direction of the arrow D81 in the figure, and also serves as a backup roller for the secondary transfer roller 121. A rubber layer having a thickness of about 3 mm and a volume resistivity of 1000 kΩ · cm or less is formed on the peripheral surface of the driving roller 82, and secondary transfer is omitted by grounding through a metal shaft. The conductive path of the secondary transfer bias supplied from the bias generation unit via the secondary transfer roller 121 is used. When the rubber layer having high friction and shock absorption is provided on the driving roller 82 in this way, the sheet enters the contact portion (secondary transfer position TR2) between the driving roller 82 and the secondary transfer roller 121. Is difficult to be transmitted to the transfer belt 81, and image quality deterioration can be prevented.

  The sheet feeding unit 11 includes a sheet feeding unit having a sheet feeding cassette 77 capable of stacking and holding sheets and a pickup roller 79 that feeds sheets one by one from the sheet feeding cassette 77. The sheet fed from the sheet feeding unit by the pickup roller 79 is fed to the secondary transfer position TR2 along the sheet guide member 15 after the sheet feeding timing is adjusted by the registration roller pair 80.

  The secondary transfer roller 121 is provided so as to be able to come into contact with and separate from the transfer belt 81 and is driven to come into contact with and separate from a secondary transfer roller drive mechanism (not shown). The fixing unit 13 includes a heating roller 131 that includes a heating element such as a halogen heater and is rotatable, and a pressure unit 132 that presses and biases the heating roller 131. Then, the sheet on which the image is secondarily transferred is guided to a nip portion formed by the heating roller 131 and the pressure belt 1323 of the pressure portion 132 by the sheet guide member 15, and in the nip portion, a predetermined value is provided. The image is heat-fixed at temperature. The pressure unit 132 includes two rollers 1321 and 1322 and a pressure belt 1323 stretched between them. A nip portion formed by the heating roller 131 and the pressure belt 1323 by pressing the belt tension surface stretched by the two rollers 1321 and 1322 against the peripheral surface of the heating roller 131 among the surfaces of the pressure belt 1323. Is configured to be widely taken. Further, the sheet thus subjected to the fixing process is conveyed to a paper discharge tray 4 provided on the upper surface of the housing body 3.

  Further, in this apparatus, a cleaner portion 71 is disposed to face the blade facing roller 83. The cleaner unit 71 includes a cleaner blade 711 and a waste toner box 713. The cleaner blade 711 removes foreign matters such as toner and paper dust remaining on the transfer belt after the secondary transfer by bringing the tip of the cleaner blade 711 into contact with the blade facing roller 83 via the transfer belt 81. The foreign matter removed in this way is collected in a waste toner box 713. Further, the cleaner blade 711 and the waste toner box 713 are integrally formed with the blade facing roller 83. Therefore, when the blade facing roller 83 moves as will be described below, the cleaner blade 711 and the waste toner box 713 also move together with the blade facing roller 83.

  FIG. 5 is a perspective view showing an outline of the line head according to the present invention. FIG. 6 is a cross-sectional view in the width direction of the line head shown in FIG. As described above, the line head 29 is arranged with respect to the photosensitive drum 21 such that the longitudinal direction LGD corresponds to the main scanning direction MD and the width direction LTD corresponds to the sub-scanning direction SD. The longitudinal direction LGD and the width direction LTD are substantially orthogonal to each other. The line head 29 includes a case 291, and positioning pins 2911 and screw insertion holes 2912 are provided at both ends of the case 291 in the longitudinal direction LGD. Then, the positioning pin 2911 covers the photosensitive drum 21 and is fitted into a positioning hole (not shown) formed in a photosensitive cover (not shown) positioned with respect to the photosensitive drum 21, thereby The head 29 is positioned with respect to the photosensitive drum 21. Further, the line head 29 is positioned and fixed with respect to the photosensitive drum 21 by screwing and fixing a fixing screw into a screw hole (not shown) of the photosensitive member cover through the screw insertion hole 2912.

  The case 291 holds the lens array 299 at a position facing the surface of the photosensitive drum 21, and includes a light shielding member 297 and a head substrate 293 in the order close to the lens array 299. The head substrate 293 is formed of a material (for example, glass) that can transmit a light beam. A plurality of bottom emission organic EL (Electro-Luminescence) elements are arranged as light emitting elements 2951 on the back surface of the head substrate 293 (the surface opposite to the lens array 299 of the two surfaces of the head substrate 293). ing. The plurality of light emitting elements 2951 are arranged in groups for each light emitting element group 295, as will be described later. The light beams emitted from the respective light emitting element groups 295 are transmitted from the back surface to the front surface of the head substrate 293 and directed to the light shielding member 297.

  A plurality of light guide holes 2971 are formed in the light shielding member 297 on a one-to-one basis with respect to the plurality of light emitting element groups 295. Further, the light guide hole 2971 is formed as a substantially cylindrical hole penetrating the light shielding member 297 with a line parallel to the normal line of the head substrate 293 as a central axis. Therefore, among the light beams emitted from the light emitting element group 295, the light beams that are directed to other than the light guide hole 2971 corresponding to the light emitting element group 295 are blocked by the light blocking member 297. Thus, all the light emitted from one light emitting element group 295 is directed to the lens array 299 through the same light guide hole 2971, and interference between light beams emitted from different light emitting element groups 295 is prevented by the light shielding member 297. The Then, the light beam that has passed through the light guide hole 2971 formed in the light shielding member 297 is imaged as a spot on the surface of the photosensitive drum 21 by the lens array 299.

  As shown in FIG. 6, the back cover 2913 is pressed against the case 291 via the head substrate 293 by the fixing device 2914. That is, the fixing device 2914 has an elastic force that presses the back cover 2913 toward the case 291, and presses the back cover with the elastic force, thereby making the inside of the case 291 light-tight (that is, from the inside of the case 291. It is sealed so that light does not leak and so that light does not enter from the outside of the case 291. Note that a plurality of fixing devices 2914 are provided in the longitudinal direction of the case 291. The light emitting element group 295 is covered with a sealing member 294.

  FIG. 7 is a plan view schematically showing the lens array, and corresponds to the case where the lens array is viewed from the image plane side (that is, the surface side of the photosensitive drum 21). As shown in the figure, in this lens array 299, a plurality of lenses LS are arranged along the longitudinal direction LGD to form a lens row LSR, and three lens rows are arranged in the width direction LTD. These three lens rows LSR1 to LSR3 are shifted from each other in the longitudinal direction LGD so that the positions of the lenses LS are different from each other in the longitudinal direction LGD. As a result, the positions of the lenses LS in the longitudinal direction LGD are different from each other.

  FIG. 8 is a cross-sectional view of the lens array in the longitudinal direction, and corresponds to a case where the lens array is viewed in a cross section including the optical axis OA of each lens. In the figure, the upper side is the image plane side, and the lower side is the light emitting element group side. In the lens array 299, one lens substrate LB formed of glass is provided, and the lens LS is configured by two lens surfaces LSF1 and LSF2 arranged in the direction of the optical axis OA so as to sandwich the lens substrate LB. . These lens surfaces LSF1, LSF2 can be formed of, for example, a photocurable resin. Of the two lens surfaces, the lens surface LSF1 is formed on the back surface LBF1 of the lens substrate LB, and the lens surface LSF2 is formed on the surface LBF2 of the lens substrate LB. The lens row LSR is configured by arranging the lenses LS in the longitudinal direction LGD.

  FIG. 9 is a diagram showing the configuration of the back surface of the head substrate, which corresponds to the case where the back surface is viewed from the front surface of the head substrate. In FIG. 9, the lens LS is indicated by a two-dot chain line. This is for indicating that the light emitting element groups 295 are provided in one-to-one relationship with the lens LS. It does not indicate that it is arranged on the back surface of the head substrate. As shown in FIG. 9, three light emitting element group rows 295R in which a plurality of light emitting element groups 295 are arranged along the longitudinal direction LGD are arranged in three rows (295R_A, 295R_B, 295R_C) in the width direction LTD. In each light emitting element group row 295R_A to 295R_C, a plurality of light emitting element groups 295 are arranged with a space SC therebetween. The light emitting element group rows 295R are shifted from each other in the longitudinal direction LGD, and the positions of the light emitting element groups 295 are different from each other in the longitudinal direction LGD. More specifically, the positions LCA, LCB, and LCC in the longitudinal direction LGD of the light emitting element groups 295A1, 295B1, and 295C1 are different from each other. In the figure, positions LCA, LCB, and LCC are representatively represented by perpendicular legs drawn from the center of gravity of each light emitting element group 295A1, 295B1, and 295C1 to the longitudinal LGD axis.

  Since each light emitting element group row 295R is shifted in the longitudinal direction LGD as described above, each light emitting element group 295 is opposed to the space SC of the light emitting element group row 295R to which it does not belong in the width direction LTD. It becomes. Specifically, for example, the light emitting element group 295A2 faces the space SC of the light emitting element group rows 295R_B and 295R_C in the width direction LTD.

  For later explanation, a region located on one side in the width direction LTD from the plurality of light emitting element groups 295 arranged in this manner is referred to as one region AR. The one area AR is an area on the back surface of the head substrate 293, that is, the surface on which the light emitting element 2951 is formed.

  In each light emitting element group 295, light emitting element rows 2951R in which four light emitting elements 2951 are arranged in the longitudinal direction LGD are arranged side by side in the width direction LTD. The light emitting element rows 2951R are arranged so as to be shifted by the light emitting element pitch Pel in the longitudinal direction LGD, and the positions of the respective light emitting elements 2951 are different from each other in the longitudinal direction LGD. Thus, in the light emitting element group 295, two columns of light emitting element rows 2951R are arranged in a staggered manner.

  FIG. 10 is a plan view showing a connection mode of wirings to the light emitting element group in the first embodiment. As shown in the drawing, a wiring WL is connected to each of the plurality of light emitting elements 2951 included in the light emitting element group 295. Thus, the plurality of wirings WL connected to the light emitting element group 295 are bundled as a wiring bundle WLB, and the wiring bundle WLB is drawn to the outside of the lens LS. In the first embodiment, all the wirings WL (or wiring bundles WLB) drawn from each light emitting element group 295 are drawn to one area AR of the head substrate 293. At this time, the wiring WL drawn from one light emitting element group row 295R to the other area AR beyond the other light emitting element group row 295R is drawn through the space SC of the other light emitting element group row 295R. That is, the wiring WL drawn from the light emitting element group row 295R_B passes through the space SC of the light emitting element group row 295R_C and is drawn to the one area AR. Further, the wiring WL drawn from the light emitting element group row 295R_A passes through the space SC of the light emitting element group row 295R_B, and further passes through the space SC of the light emitting element group row 295R_C, and is drawn to the one area AR.

  In other words, the connection portion 2931 is provided in the one area AR. That is, the connection portion 2931 is arranged on one side opposite to the light emitting element group 295A2 in the width direction LTD with respect to the light emitting element groups 295B1 and 295B2. The wiring WL connected to the light emitting element 2951 of the light emitting element group 295A2 is electrically connected to the connection portion 2931 through the light emitting element group 295B1 and the light emitting element group 295B2. Further, the connection portion 2931 is disposed on one side opposite to the light emitting element group 295B2 in the width direction LTD with respect to the light emitting element groups 295C1 and 295C2. Then, the wiring WL connected to the light emitting element 2951 of the light emitting element group 295B2 passes between the light emitting element group 295C1 and the light emitting element group 295C2, and is electrically connected to the connection portion 2931.

  FIG. 11 is a diagram illustrating an arrangement relationship between the wiring bundle and the driver IC in the first embodiment. In the figure, only the wiring bundle WLB drawn to the outside of the lens LS is shown, and the details of the wiring WL connected to each light emitting element 2951 of the light emitting element group 295 are as shown in FIG. Therefore, the description is omitted. As shown in FIG. 11, a plurality of driver ICs (electric circuits) 300 are arranged in the longitudinal direction LGD in one area AR of the head substrate 293. These driver ICs 300 can be mounted on a head substrate 293 which is a glass substrate by so-called chip on glass technology. Each driver IC 300 is connected to the wiring bundle WLB drawn to the one area AR as described above. In other words, each driver IC 300 is electrically connected to a connection portion 2931 (FIG. 10) provided in one area AR, and is electrically connected to the wiring bundle WLB via this connection portion 2931. Further, one end E1 of the FPC 310 is attached to one area AR of the head substrate 293, and this one end E1 is connected to the driver IC 300. The other end E2 of the FPC 310 is configured to be pulled out to the outside of the head substrate 293 and to receive video data VD output from the head controller HC. Therefore, when the head controller HC outputs the video data VD at an appropriate timing (FIG. 4), the video data VD is input to the other end E2 of the FPC 310. The video data VD thus input to the other end E2 of the FPC 310 is input to the driver IC 300 connected to the one end E1 of the FPC 310. In the driver IC 300, the video data VD is converted into a drive signal for driving each light emitting element 2951. This drive signal is supplied to each light emitting element 2951 through the wiring WL. Each light emitting element 2951 to which the drive signal is given emits light beams having the same wavelength. The light emitting surface of the light emitting element 2951 is a so-called perfect diffusion surface light source, and the light beam emitted from the light emitting surface follows Lambert's cosine law.

  FIG. 12 is a diagram showing a spot forming operation by the above-described line head. The spot forming operation by the line head in this embodiment will be described below with reference to FIGS. In order to facilitate understanding of the invention, a case where a line latent image is formed by arranging a plurality of spots in a straight line extending in the main scanning direction MD will be described here. In general, in such a latent image forming operation, a plurality of light emitting elements are set in a predetermined manner according to video data VD output from the head controller HC while conveying the surface of the photosensitive drum 21 in the sub-scanning direction SD (width direction LTD). By emitting light at this timing, a plurality of spots are formed side by side in a straight line extending in the main scanning direction MD (longitudinal direction LGD). Details will be described below.

  First, among the light emitting element rows 2951R belonging to the most upstream light emitting element groups 295A1, 295A2,... In the width direction LTD, the light emitting element rows 2951R on the downstream side in the width direction LTD are caused to emit light. The plurality of light beams emitted by the light emitting operation are imaged on the surface of the photosensitive drum by the lens LS. In the present embodiment, the lens LS has an inverted characteristic, and the light beam from the light emitting element 2951 is imaged while being inverted. In this way, a spot is formed at the position of the “first” hatching pattern in FIG. In the figure, white circles represent spots that have not yet been formed and are to be formed in the future. In the same figure, the spots labeled with reference numerals 295C1, 295B1, 295A1, and 295C2 indicate spots formed by the light emitting element groups 295 corresponding to the reference numerals assigned thereto.

  Next, among the light emitting element rows 2951R belonging to the light emitting element groups 295A1, 295A2,..., The light emitting element row 2951R on the upstream side in the width direction LTD is caused to emit light. The plurality of light beams emitted by the light emitting operation are imaged on the surface of the photosensitive drum by the lens LS. In this way, a spot is formed at the position of the “second” hatching pattern in FIG. Here, the reason why light is emitted sequentially from the light emitting element row 2951R on the downstream side in the width direction WD is to correspond to the fact that the lens LS has an inverted characteristic.

  Next, among the light emitting element rows 2951R belonging to the second light emitting element group 295B1,... From the upstream side in the width direction, the light emitting element rows 2951R on the downstream side in the width direction LTD are caused to emit light. The plurality of light beams emitted by the light emitting operation are imaged on the surface of the photosensitive drum by the lens LS. Thus, a spot is formed at the position of the “third” hatching pattern in FIG.

  Next, among the light emitting element rows 2951R belonging to the second light emitting element group 295B1,... From the upstream side in the width direction, the light emitting element row 2951R on the upstream side in the width direction LTD is caused to emit light. The plurality of light beams emitted by the light emitting operation are imaged on the surface of the photosensitive drum by the lens LS. Thus, a spot is formed at the position of the “fourth” hatching pattern in FIG.

  Next, among the light emitting element rows 2951R belonging to the third light emitting element group 295C1,... From the upstream side in the width direction, the light emitting element rows 2951R on the downstream side in the width direction LTD are caused to emit light. The plurality of light beams emitted by the light emitting operation are imaged on the surface of the photosensitive drum by the lens LS. Thus, a spot is formed at the position of the “fifth” hatching pattern in FIG.

  Finally, among the light emitting element rows 2951R belonging to the third light emitting element group 295C1,... From the upstream side in the width direction, the light emitting element row 2951R on the upstream side in the width direction LTD is caused to emit light. The plurality of light beams emitted by the light emitting operation are imaged on the surface of the photosensitive drum by the lens LS. Thus, a spot is formed at the position of the “sixth” hatching pattern in FIG. In this way, by performing the first to sixth light emission operations, a plurality of spots are formed side by side in a straight line extending in the longitudinal direction LGD (main scanning direction MD).

  Thus, in the first embodiment, the plurality of light emitting element group rows 295R are provided side by side in the width direction LTD. In the light emitting element group row 295R, the plurality of light emitting element groups 295 are arranged with a space SC therebetween, and the positions of the light emitting element groups 295 are different from each other in the longitudinal direction LGD. 295R is displaced from each other in the longitudinal direction LGD. Accordingly, the wiring WL drawn from the one light emitting element group row 295R to the one area AR beyond the other light emitting element group row 295R is drawn out through the space SC of the other light emitting element group row 295R, whereby the wiring WL Can be easily pulled out to the one area AR. Therefore, the FPC 310 connected to the wiring WL via the driver IC 300 can also be provided in this one area AR, and the manufacturing process of the line head 29 can be simplified and the manufacturing cost can be reduced.

  In other words, in the first embodiment, the connection portion 2931 is arranged on one side opposite to the light emitting element group 295A2 in the width direction LTD with respect to the light emitting element groups 295B1 and 295B2. The wiring WL connected to the light emitting element 2951 of the light emitting element group 295A2 (corresponding to “first light emitting element group” of the present invention) is light emitting element group 295B1 (corresponding to “second light emitting element group” of the present invention). And the light emitting element group 295B2 (corresponding to the “third light emitting element group” of the present invention) and are electrically connected to the connection portion 2931. Further, the connection portion 2931 is disposed on one side opposite to the light emitting element group 295B2 in the width direction LTD with respect to the light emitting element groups 295C1 and 295C2. The wiring WL connected to the light emitting element 2951 of the light emitting element group 295B2 (corresponding to the “first light emitting element group” of the present invention) is the light emitting element group 295C1 (corresponding to the “second light emitting element group” of the present invention). And the light emitting element group 295C2 (corresponding to the “third light emitting element group” of the present invention) and are electrically connected to the connection portion 2931. Accordingly, the light emitting element group 295B1 and the light emitting element group 295B2 can be effectively used between the light emitting element group 295C1 and the light emitting element group 295C2. Thereby, the enlargement of the head substrate 293 can be suppressed, and the manufacturing cost of the line head 29 can be reduced.

  In the first embodiment, the driver IC 300 is provided on the head substrate 293. Therefore, in the first embodiment, since the driver IC 300 can be disposed relatively close to the light emitting element 2951, it is possible to supply the light emitting element 2951 with a drive signal that is less blunt due to stray capacitance or the like.

  By the way, in 1st Embodiment, the three light emitting element group rows 295R are arrange | positioned along with the width direction LTD. In each light emitting element group 295, two light emitting element rows 2951R in which four light emitting elements 2951 are arranged in the longitudinal direction LGD are arranged in the width direction LTD. However, the number of the light emitting element group rows 295R and the configuration of the light emitting element groups 295 are not limited to the contents of the first embodiment, and can be changed as follows, for example.

C. Second Embodiment FIG. 13 is a plan view showing a connection mode of wiring to a light emitting element group in a second embodiment. FIG. 14 is a diagram illustrating an arrangement relationship between the wiring bundle and the driver IC in the second embodiment. In the following description, differences from the first embodiment will be mainly described, and common portions will be denoted by corresponding reference numerals and description thereof will be omitted. As shown in FIG. 13, in the second embodiment, two light emitting element group rows 295R are arranged side by side in the width direction LTD. That is, in the second embodiment, a plurality of light emitting element group rows 295R are arranged in a staggered pattern in the longitudinal direction LGD. Further, as shown in FIG. 14, a plurality of lenses LS are also arranged in a staggered manner in the longitudinal direction LGD corresponding to the arrangement of the light emitting element groups 295. Further, in each light emitting element group 295, two light emitting element rows 2951R in which six light emitting elements 2951 are arranged in the longitudinal direction LGD are arranged in the width direction LTD (FIG. 13). These light emitting element rows 2951R are arranged to be shifted from each other in the longitudinal direction LGD, and as a result, the positions of the respective light emitting elements 2951 are different from each other in the longitudinal direction LGD.

  Thus, also in the second embodiment, a plurality of light emitting element group rows 295R are provided side by side in the width direction LTD. Further, as shown in FIG. 13, in the light emitting element group row 295R, the plurality of light emitting element groups 295 are arranged with a space SC therebetween, and the positions of the light emitting element groups 295 are different from each other in the longitudinal direction LGD. In addition, the light emitting element group rows 295R are shifted from each other in the longitudinal direction LGD. Accordingly, the wiring WL drawn from one light emitting element group row 295R (light emitting element group row 295R_A) to another region AR beyond the other light emitting element group row 295R (light emitting element group row 295R_B) is connected to the other light emitting element group. By drawing out through the space SC of the row 295R (light emitting element group row 295R_B), the wiring WL can be easily drawn out to the one area AR. Therefore, the FPC 310 connected to the wiring WL via the driver IC 300 can also be provided in this one area AR, and the manufacturing process of the line head 29 can be simplified and the manufacturing cost can be reduced.

  In other words, also in the second embodiment, the connection portion 2931 is provided in the one area AR. That is, the connection portion 2931 is arranged on one side opposite to the light emitting element group 295A2 in the width direction LTD with respect to the light emitting element groups 295B1 and 295B2. The wiring WL connected to the light emitting element 2951 of the light emitting element group 295A2 (corresponding to “first light emitting element group” of the present invention) is light emitting element group 295B1 (corresponding to “second light emitting element group” of the present invention). And the light emitting element group 295B2 (corresponding to the “third light emitting element group” of the present invention) and are electrically connected to the connection portion 2931. Therefore, the space between the light emitting element group 295B1 and the light emitting element group 295B2 can be used effectively. Thereby, the enlargement of the head substrate 293 can be suppressed, and the manufacturing cost of the line head 29 can be reduced.

  In the first and second embodiments, the driver IC 300 is provided on the head substrate 293. However, the arrangement position of the driver IC 300 is not limited to this, and can be changed as follows.

D. Third Embodiment FIG. 15 is a diagram illustrating an arrangement relationship between a wiring bundle and a driver IC in the third embodiment. In the following, differences from the first and second embodiments will be mainly described, and common portions are denoted by corresponding reference numerals and description thereof is omitted. As shown in the figure, one end E1 of the FPC 310 attached to one area AR of the head substrate 293 is connected to the wiring bundle WLB (or wiring WL). In the third embodiment, the driver IC 300 is provided between the one end E1 and the other end E2 of the FPC 310. The driver IC 300 is mounted on the FPC 310 by so-called chip on film technology.

  Therefore, when the head controller HC outputs the video data VD at an appropriate timing (FIG. 4), the video data VD is input to the other end E2 of the FPC 310. The video data VD thus input to the other end E2 of the FPC 310 is converted into a drive signal by the driver IC 300 mounted on the FPC 310 and output from the one end E1 of the FPC 310. Each light emitting element 2951 is driven by this drive signal.

  As described above, also in the third embodiment, the FPC 310 is provided in the one area AR, and the manufacturing process of the line head 29 can be simplified and the manufacturing cost can be reduced.

  In the third embodiment, the driver IC 300 is provided between one end E1 and the other end E2 of the FPC 310. Accordingly, since it is not necessary to provide the driver IC 300 on the head substrate 293, the head substrate 293 can be made small, and the line head 29 can be configured compactly.

E. Fourth Embodiment FIG. 16 is a diagram showing an arrangement relationship between a wiring bundle and a driver IC in the fourth embodiment. Hereinafter, differences from the above-described embodiment will be mainly described, and common portions will be denoted by corresponding reference numerals and description thereof will be omitted. As shown in the figure, a plurality of FPCs 310 are mounted side by side in the longitudinal direction LGD. One end E1 of the FPC 310 attached to one area AR of the head substrate 293 is connected to the wiring bundle WLB (wiring WL). The other end E2 of the FPC 310 is attached to a driver IC substrate DBS made of glass, and is connected to a driver IC 300 on the driver IC substrate DBS. That is, a plurality of driver ICs 300 are mounted on the driver IC substrate DBS by a chip-on-glass technique, and each driver IC 300 is connected to the other end E2 of the FPC 310. Further, video data VD from the head controller HC can be input to the driver IC 300.

  That is, when the head controller HC outputs the video data VD at an appropriate timing (FIG. 4), the video data VD is converted into a drive signal by the driver IC 300, and this drive signal is sent to each light emitting element 2951 through the FPC 310. Entered. Each light emitting element 2951 is driven by this drive signal.

  As described above, also in the fourth embodiment, the FPC 310 is provided in the one area AR, and the manufacturing process of the line head 29 can be simplified and the manufacturing cost can be suppressed.

  In the fourth embodiment, a plurality of driver ICs 300 are provided on a driver IC substrate DBS different from the head substrate 293. Therefore, the driver IC 300 can be relatively freely arranged and laid out, and the cost of the driver IC 300 can be suppressed.

F. Fifth Embodiment FIG. 17 is a diagram illustrating an arrangement relationship between a wiring bundle and a driver IC in the fifth embodiment. Note that FIG. 17 shows only the wiring bundle WLB drawn from some lenses LS. Hereinafter, differences from the above-described embodiment will be mainly described, and common portions will be denoted by corresponding reference numerals and description thereof will be omitted. As shown in the figure, the wiring bundle WLB drawn from each lens LS to the one area AR is gathered at one place OL in the longitudinal direction LGD. One FPC 310 is provided on the head substrate 293. That is, one end E1 of the FPC 310 is attached to one area AR of the head substrate 293, and this one end E1 is connected to the wiring bundle WLB (or wiring WL). The other end E2 of the FPC 310 is attached to a driver IC substrate DBS made of glass. A driver IC 300 is mounted on the driver IC substrate DBS by a chip-on-glass technique. The driver IC 300 receives video data VD from the head controller HC.

  Therefore, when the head controller HC outputs the video data VD at an appropriate timing (FIG. 4), the video data VD is converted into a drive signal by the driver IC 300, and this drive signal is sent to each light emitting element 2951 via the FPC 310. Entered. Each light emitting element 2951 is driven by this drive signal.

  As described above, also in the fifth embodiment, the FPC 310 is provided in the one area AR, and the manufacturing process of the line head 29 can be simplified and the manufacturing cost can be suppressed.

  Further, in the fifth embodiment, the wirings WL are drawn together at one place in the longitudinal direction LGD, and one end E1 of the FPC 310 is connected to the wirings WL. Therefore, in the fifth embodiment, it is only necessary to attach one FPC 310 to the head substrate 293, and the process of attaching the FPC 310 is only once, so that the manufacturing cost can be suppressed.

G. Sixth Embodiment FIG. 18 is a plan view showing a connection mode of wirings to a light emitting element group in a sixth embodiment. Hereinafter, differences from the above-described embodiment will be mainly described, and common portions will be denoted by corresponding reference numerals and description thereof will be omitted.

  In the sixth embodiment, two light emitting element group rows of light emitting element group rows 295R_A and 295R_B are arranged on the head substrate 293. Each light emitting element group 295 includes one side (connection side) light emitting element row 2951R_2 (corresponding to the “second light emitting element row” of the present invention) and the other side light emitting element row 2951R_1 (“first” of the present invention). 2 light emitting element rows) (corresponding to “light emitting element rows”). Similarly to the first embodiment shown in FIG. 10, the plurality of wirings WL connected to the light emitting element group 295 are bundled as a wiring bundle WLB, and the wiring bundle WLB is drawn to the outside of the lens LS. . Similarly to the first embodiment, all the wirings WL drawn from each light emitting element group 295 are electrically connected to the connection portion 2931 on one side of the head substrate 293 in the width direction LTD. Similarly to the first embodiment, the wiring WL drawn from the light emitting element group 295A2 (corresponding to the “first light emitting element group” of the present invention) is connected to the light emitting element group 295B1 (“second light emitting element group” of the present invention). ) And the light emitting element group 295B2 (corresponding to the “third light emitting element group” of the present invention), and is electrically connected to the connection portion 2931 on one side. Therefore, as in the first embodiment, the space between the light emitting element groups can be effectively utilized. In addition, the FPC 310 is attached to the connection portion 2931 by, for example, an anisotropic conductive film.

  In the sixth embodiment, the light emitting element belonging to the other side light emitting element row 2951R_1 (corresponding to the “first light emitting element row” of the present invention) (for example, light emitting element 2951_1, corresponding to the “first light emitting element” of the present invention). ) WL (corresponding to the “first wiring” in the present invention) WL is once drawn toward the other side opposite to the connection portion 2931 and then bent to be light-emitting element rows on one side. It passes through the outside of the 2951R_2 and is electrically connected to the connection portion 2931 on one side. Note that a wiring (for example, the light emitting element 2951_2, which corresponds to the “second light emitting element” of the present invention) belonging to the light emitting element row 2951R_2 (corresponding to the “second light emitting element row” of the present invention) on one side ( WL (corresponding to the “second wiring” of the present invention) is directly pulled out toward the connection portion 2931 on one side.

  In addition, among the light emitting elements 2951 belonging to the other light emitting element row 2951R_1 of the light emitting element group 295A2, a wiring (corresponding to the “first wiring” in the present invention) WL drawn from the left half light emitting element 2951 in FIG. The light emitting element group 295A2 (corresponding to the “first light emitting element group” of the present invention) and the light emitting element group 295A1 (corresponding to the “fourth light emitting element group” of the present invention) are arranged. As described above, according to the sixth embodiment, the wiring WL does not pass through the gap between the light emitting elements 2951 belonging to the light emitting element row 2951R_2 on one side. Accordingly, the interval between the light emitting elements 2951 can be reduced.

H. 7th Embodiment FIG. 19: is a top view which shows the connection aspect of the wiring with respect to the light emitting element group in 7th Embodiment. Hereinafter, differences from the sixth embodiment will be mainly described, and common portions are denoted by corresponding reference numerals and description thereof is omitted.

  Each light emitting element group 295 includes two light emitting element rows in the sixth embodiment, whereas the seventh embodiment includes three light emitting element rows. That is, the light emitting element row 2951R_2 (corresponding to the “second light emitting element row” of the present invention) on one side (the connection portion 2931 side) in the width direction LTD, and the light emitting element row 2951R_3 (the “third light emitting element row” of the present invention). Equivalent to “row”). In the seventh embodiment, as in the sixth embodiment, the light emitting elements belonging to the light emitting element row 2951R_1 disposed on the other side (for example, the light emitting element 2951_1, which corresponds to the “first light emitting element” of the present invention). Wiring (corresponding to the “first wiring” of the present invention) WL drawn from the wiring is once drawn toward the other side (the side opposite to the connection portion 2931), then bent, and light emitting element rows 2951R_2 and 2951R_3. Is electrically connected to the connection portion 2931 on one side.

  In addition, the wiring WL drawn from the light emitting elements (for example, the light emitting elements 2951_2 and 2951_3) belonging to the light emitting element rows 2951R_2 and 2951R_3 is directly drawn out toward one side and is electrically connected to the connection portion 2931. That is, a wiring (corresponding to a “second wiring” in the present invention) WL drawn from a light emitting element belonging to the light emitting element row 2951R_2 (eg, the light emitting element 2951_2) is a light emitting element belonging to the light emitting element row 2951R_3 (eg, the light emitting element 2951_3). It is electrically connected to the connection portion 2931 on one side through the gap. Thus, according to the seventh embodiment, wiring is prevented from passing through the gap between the light emitting elements 2951 belonging to the light emitting element row 2951R as much as possible. Accordingly, the interval between the light emitting elements 2951 can be reduced.

  In the seventh embodiment, each light emitting element group 295 includes three light emitting element rows, ie, light emitting element rows 2951R_1, 2951R_2, and 2951R_3, in order from the other side to the one side. Is not limited to this. For example, each light emitting element group 295 may include N light emitting element rows (N is an odd number of 3 or more) in order from one side to the other side. In this modification, the wiring drawn out from the light emitting elements belonging to the (N-1) / 2 light emitting element rows arranged on the other side is once drawn toward the other side and then bent, What is necessary is just to comprise so that it may electrically connect with the connection part 2931 of one side through the outer side of the light emitting element row arrange | positioned at one side. As a result, the wiring can be prevented from passing through the gap between the light emitting elements belonging to the light emitting element row as much as possible.

I. Eighth Embodiment FIG. 20 is a plan view showing a connection mode of wirings with respect to a light emitting element group in an eighth embodiment. Hereinafter, differences from the seventh embodiment will be mainly described, and common portions are denoted by corresponding reference numerals and description thereof is omitted.

  Each light emitting element group 295 includes three light emitting element rows in the seventh embodiment, whereas the eighth embodiment includes four light emitting element rows. That is, the light emitting element row 2951R_1 (corresponding to the “first light emitting element row” of the present invention) on the other side in the width direction LTD (on the side opposite to the connection portion 2931) and the light emitting element row 2951R_4 (“fourth of the present invention”). Equivalent to “light emitting element row”). In the eighth embodiment, as in the seventh embodiment, the wiring WL drawn from the light emitting element (for example, the light emitting element 2951_4) belonging to the light emitting element row 2951R_4 arranged on the most other side is temporarily on the other side. After being drawn out, it is bent, passes through the outside of the light emitting element rows 2951R_1 to 2951R_3, is drawn out to one side, and is electrically connected to the connection portion 2931.

  In addition, the wiring (corresponding to the “first wiring” of the present invention) WL drawn from the light emitting elements belonging to the light emitting element row 2951R_1 (for example, the light emitting element 2951_1, which corresponds to the “first light emitting element” of the present invention) WL is also implemented in the seventh embodiment. In the same manner as in the embodiment, after being pulled out toward the other side, it is bent, passed through the outside of the light emitting element rows 2951R_2 and 2951R_3, pulled out to one side, and electrically connected to the connection portion 2931. Yes. At this time, the wiring (corresponding to the “first wiring” of the present invention) WL drawn from the light emitting element belonging to the light emitting element row 2951R_1 (for example, the light emitting element 2951_1, which corresponds to the “first light emitting element” of the present invention) WL is the light emitting element The light-emitting elements belonging to the row 2951R_4 (for example, the light-emitting elements 2951_4) are drawn out to one side and electrically connected to the connection portion 2931.

  In addition, the wiring WL drawn from the light emitting elements belonging to the light emitting element rows 2951R_2 and 2951R_3 (for example, the light emitting elements 2951_2 and 2951_3) is directly pulled out toward one side as in the seventh embodiment, and is connected to the connection portion 2931. Electrically connected. That is, a wiring (corresponding to a “second wiring” in the present invention) WL drawn from a light emitting element belonging to the light emitting element row 2951R_2 (eg, the light emitting element 2951_2) is a light emitting element belonging to the light emitting element row 2951R_3 (eg, the light emitting element 2951_3). It is pulled out toward one side through the space and is electrically connected to the connection portion 2931. As described above, according to the eighth embodiment, wiring is prevented from passing through the gap between the light emitting elements 2951 belonging to the light emitting element row 2951R as much as possible. Accordingly, the interval between the light emitting elements 2951 can be reduced.

  In the eighth embodiment, each light emitting element group 295 includes four light emitting element rows of light emitting element rows 2951R_4, 2951R_1, 2951R_2, and 2951R_3 in order from the other side to one side. The number of lines is not limited to this. For example, each light emitting element group 295 may include M light emitting element rows (M is an even number of 2 or more) in order from one side to the other side. In this modification, the wiring drawn out from the light emitting elements belonging to the M / 2 rows of light emitting elements arranged on the other side is once drawn out toward the other side, then bent and arranged on one side. What is necessary is just to comprise so that it may electrically connect with the connection part 2931 of one side through the outer side of the provided light emitting element row | line | column. Accordingly, it is possible to prevent the wiring from passing through the gap between the light emitting elements belonging to the light emitting element row as much as possible.

J. et al. Others As described above, in the first to eighth embodiments, the longitudinal direction LGD corresponds to the “first direction” of the present invention, the width direction LTD corresponds to the “second direction” of the present invention, and the photosensitive drum 21. Corresponds to the “latent image carrier” of the present invention, and the surface of the photosensitive drum 21 corresponds to the “image surface” of the present invention. The FPC 310 corresponds to the “connection member” of the present invention, the video data VD corresponds to the “light emission control signal” of the present invention, and the video data VD and the drive signal relate to the “light emission control signal” of the present invention. Corresponds to “Signal”. The FPC 310 corresponds to the “connection circuit” of the present invention, and the driver IC substrate DBS corresponds to the “drive substrate” of the present invention.

  The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention. For example, in the above embodiment, the light emitting element group 295 is composed of two light emitting element rows 2951R arranged in the width direction LTD. However, the configuration of the light emitting element group 295 is not limited to this. For example, the number of light emitting element rows 2951R may be three or more.

  In the above embodiment, two or three light emitting element group rows 295R are arranged in the width direction LTD, but the number of light emitting element group rows 295R is not limited to this and may be three or more.

  In the first embodiment, the case where the driver IC 300 is used as the “electric circuit” of the present invention has been described. However, a circuit other than the driver IC can also be used as the “electric circuit” of the present invention.

  Each light emitting element 2951 can also be driven by so-called time-division driving. That is, each light emitting element 2951 is driven by time-division driving, which has been conventionally proposed in Japanese Patent Laid-Open No. 11-268333, Japanese Patent Laid-Open No. 2007-203555, Japanese Patent Laid-Open No. 2007-160650, or the like. May be. When configured in this manner, the number of driver ICs 300 can be reduced, and the manufacturing cost can be suppressed.

  In the above embodiment, the case where an organic EL element is used as the light emitting element 2951 has been described. However, the configuration of the light emitting element 2951 is not limited thereto, and for example, an LED (Light Emitting Diode) may be used as the light emitting element 2951.

  In the above embodiment, the FPC 310 is used as the “connection member”. That is, in the first and second embodiments, the video data VD is input to the other end E2, and the FPC 310 from which the video data VD is output to the one end E1 functions as a “connection member”. In the third embodiment, the FPC 310 in which the video data VD is input to the other end E2 and the drive signal obtained by converting the video data VD is output to the one end E1 functions as a “connecting member”. is doing. Further, in the fourth and fifth embodiments, the FPC 310 in which the drive signal is input to the other end E2 and the drive signal is output to the one end E1 functions as a “connecting member”. However, similarly to the FPC 310, another member that can output a signal corresponding to the signal input to the other end E2 from the one end E1 can be used as the “connecting member”.

Explanatory drawing of the term used by this specification. Explanatory drawing of the term used by this specification. 1 is a diagram illustrating an example of an image forming apparatus according to the present invention. FIG. 4 is a diagram illustrating an electrical configuration of the image forming apparatus in FIG. 3. The perspective view which shows the outline of the line head concerning this invention. FIG. 6 is a cross-sectional view in the width direction of the line head shown in FIG. 5. The top view which shows the outline of a lens array. Sectional drawing of the longitudinal direction of a lens array. The figure which shows the structure of the back surface of a head board | substrate. The top view which shows the wiring with respect to the light emitting element group in 1st Embodiment. The figure which shows the arrangement | positioning relationship between the wiring bundle | flux and driver IC in 1st Embodiment. The figure which shows the spot formation operation | movement by a line head. The top view which shows the wiring with respect to the light emitting element group in 2nd Embodiment. The figure which shows the arrangement | positioning relationship between the wiring bundle | flux and driver IC in 2nd Embodiment. The figure which shows the arrangement | positioning relationship between the wiring bundle | flux and driver IC in 3rd Embodiment. The figure which shows the arrangement | positioning relationship between the wiring bundle | flux and driver IC in 4th Embodiment. The figure which shows the arrangement | positioning relationship between the wiring bundle | flux and driver IC in 5th Embodiment. The top view which shows the connection aspect of the wiring with respect to the light emitting element group of 6th Embodiment. The top view which shows the connection aspect of the wiring with respect to the light emitting element group of 7th Embodiment. The top view which shows the connection aspect of the wiring with respect to the light emitting element group of 8th Embodiment.

Explanation of symbols

  21Y, 21K ... photosensitive drum (latent image carrier), 29 ... line head, 293 ... head substrate, 295 ... light emitting element group, 295R ... light emitting element group row, 2951 ... light emitting element, 2951R ... light emitting element row, 299 ... Lens array, 300 ... driver IC, 310 ... FPC, LS ... lens, MD ... main scanning direction, SD ... sub-scanning direction, LGD: longitudinal direction (first direction), LTD ... width direction (second direction), WL ... Wiring, WLB ... Wiring bundle, E1 ... One end, E2 ... Other end, AR ... One area, DBS ... Substrate for driver IC

Claims (15)

A head substrate;
A first light emitting element group disposed on the head substrate and having a first light emitting element and a second light emitting element;
A second light emitting element group and a third light emitting element group disposed in the first direction of the head substrate;
A first wiring disposed between the second light emitting element group and the third light emitting element group of the head substrate and electrically connected to the first light emitting element;
A second wiring disposed between the second light emitting element group and the third light emitting element group of the head substrate and electrically connected to the second light emitting element;
A line head, comprising: a connection portion disposed on the head substrate and electrically connected to the first wiring and the second wiring. The first light emitting element group includes a first light emitting element row having a light emitting element including the first light emitting element disposed in the first direction, and the second light emitting element disposed in the first direction. A second light emitting element row having light emitting elements including,
The line head according to claim 1, wherein the second light emitting element row is disposed so as to be positioned closer to the connection portion than the first light emitting element row.   A fourth light emitting element group is disposed in the first direction of the first light emitting element group, and the first wiring is disposed between the first light emitting element group and the fourth light emitting element group. The line head according to claim 2.   The line head according to claim 3, wherein the first wiring is wired on a side opposite to a side on which the connection portion is arranged, and is electrically connected to the connection portion. The first light emitting element group includes a third light emitting element row disposed so as to be positioned closer to the connection portion than the second light emitting element row.
The line head according to claim 4, wherein the second wiring is disposed between light emitting elements in the third light emitting element row. The first light emitting element group includes a fourth light emitting element row disposed so as to be located on the opposite side of the connection portion from the first light emitting element row.
The line head according to claim 5, wherein the first wiring is disposed between light emitting elements in the fourth light emitting element row.   The line head according to claim 1, further comprising a connection circuit electrically connected to the connection portion of the head substrate.   An electrical circuit that is electrically connected to the connection portion of the head substrate through or without the connection circuit, and that outputs a drive signal for driving the light-emitting element based on an input light emission control signal; The line head according to claim 7.   The line head according to claim 8, wherein the electric circuit is interposed between the connection portion of the head substrate and the connection circuit.   The line head according to claim 8, wherein the electric circuit is provided in the connection circuit. A drive board on which the electric circuit is disposed;
The line head according to claim 8, wherein the electric circuit is electrically connected to the connection portion of the head substrate via the connection circuit.   The line head according to any one of claims 1 to 11, wherein the connection portion of the head substrate is configured such that the first wiring and the second wiring are gathered at one place in the first direction. A head substrate;
A first light emitting element group disposed on the head substrate and having a first light emitting element and a second light emitting element;
A second light emitting element group and a third light emitting element group disposed in the first direction of the head substrate;
A first wiring disposed between the second light emitting element group and the third light emitting element group of the head substrate and electrically connected to the first light emitting element;
A second wiring disposed between the second light emitting element group and the third light emitting element group of the head substrate and electrically connected to the second light emitting element;
A connecting portion disposed on the head substrate and electrically connected to the first wiring and the second wiring;
An image forming apparatus comprising: a controller that outputs a light emission control signal for controlling light emission of the light emitting element.   The image forming apparatus according to claim 13, further comprising a connection circuit electrically connected to the connection portion of the head substrate.   A drive signal for driving the light emitting element is output based on the light emission control signal input from the controller, which is electrically connected to the connection portion of the head substrate via the connection circuit or not. The image forming apparatus according to claim 14, further comprising an electric circuit.

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