JP2013059928A - Optical print head and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical print head that can satisfy both of the high speed data transmission and securing of signal quality corresponding to narrow width, high density and high-speed writing.SOLUTION: The optical print head includes: an organic EL substrate 101 that has a plurality of light emitting sources 102 and the electrode wiring; a lens array 105 that performs image formation of the light beam of the light emitting sources 102 on an irradiated plane; a housing 106 having a bumping part 106a holding the organic EL substrate 101 and the lens array 105 and touching a face plate of the image forming apparatus; a printed board 107 that has a driving control circuit 150 that controls driving of the light emitting source 102 and signal wiring of the driving control circuit 150, and maintains the housing 106; and a biasing means that makes the bumping part 106a abut on the face plate by biasing the printed board 107 to the irradiated plane side in a parallel direction to the substrate surface. The printed board 107 maintains the housing 106 so that the electrode wiring and the signal wiring may be connected, as the substrate surface and the light axis of the lens array 105 become in parallel.

Description

  The present invention relates to an optical print head that is a solid-state writing head using a light emitting diode array or an organic electroluminescence element array as a light source, and an image forming apparatus using the optical print head.

  Various image forming apparatuses using an electrophotographic system have been devised as image forming apparatuses such as copiers, printers, facsimiles, and their combined machines, and are well known in the art. In the image forming process, an electrostatic latent image is formed on the surface of a photosensitive drum as an image carrier, and the electrostatic latent image on the photosensitive drum is developed with a toner or the like as a developer to be visualized. The developed image is transferred to recording paper (also referred to as paper, recording material, or recording medium) by a transfer device to carry the image, and the toner image on the recording paper is fixed by a fixing device using pressure or heat. doing.

  In such an electrophotographic image forming apparatus, as an exposure means for writing an electrostatic latent image on an image carrier, a micro light emitting segment array that selectively emits light from a large number of light emitting units arranged in an array is provided. It is known to use a self-scanning optical print head.

  For example, in Patent Document 1, an LED array in which a plurality of light emitting diodes (LEDs) are arranged in a line on the substrate in the main scanning direction (rotational axis direction of a photosensitive drum as an image carrier) and the LED array are driven. And a rod lens array (hereinafter referred to as a lens array) that forms a plurality of light beams from an LED array on an image carrier are disclosed. . At this time, the LED array is mounted on the substrate so that the light beam is emitted in a direction perpendicular to the substrate surface, the substrate is disposed perpendicular to the optical axis of the lens array, and a drive IC for driving the LED array is provided. It was deployed on the substrate.

  Here, as the image forming apparatus is further downsized, the photosensitive drum as an image carrier is downsized, and the optical print is brought close to the surface of the photosensitive drum as the irradiated surface at an interval of several mm. In the solid writing method in which the head is arranged, the optical printing is performed in the rotation direction of the photosensitive drum, so-called sub-scanning direction, in consideration of the layout with the charging device, the developing device, and the cleaning device arranged around the photosensitive drum. There is a demand for narrowing the head. However, the configuration described in Patent Document 1 described above is not preferable because the LED array and the driving IC are arranged on the same substrate, which increases the size of the substrate and increases the width of the optical print head.

  On the other hand, a configuration in which the driving IC is provided on a substrate different from the LED array is conceivable, but in this case, the wiring length between the LED array and the driving IC becomes long, and noise from the wiring mixes in the optical print head. There has been a problem that the exposure characteristics are degraded. In particular, high-density writing of 1200 dpi or more is becoming the mainstream in recent years, and in the A3 size range, each of the light emitting sources of 14000 or more is individually modulated according to image data. The amount of image data transferred from the write control circuit to be generated to the optical print head has become enormous, and with the increase in speed, data transfer using a harness as in the prior art has a more problematic deterioration in the quality of the transmitted signal. It has become to.

  Therefore, in Patent Document 2, a light-emitting substrate including a substrate and a circuit unit including an LED array disposed on the substrate, and a wiring that is provided so as to be drawn from the substrate and electrically connected to the circuit unit are provided. A configuration is disclosed in which a semiconductor element having a flexible printed circuit board and having at least a part of a drive circuit for driving an LED array formed on the flexible printed circuit board is provided.

  However, even in the optical print head described in Patent Document 2, it is not sufficient to achieve both narrowing of the optical print head and ensuring signal quality in high-speed data transfer.

  The present invention has been made in view of the above-described problems in the prior art, and it is possible to achieve both the narrowing of the optical print head and the ensuring of signal quality in high-speed data transfer corresponding to high-density and high-speed writing. It is an object of the present invention to provide an optical print head that can be used and an image forming apparatus using the optical print head.

  According to the present invention provided to solve the above-described problems, at least both ends of the longitudinal direction abut on a face plate of an image forming apparatus that holds and holds an image carrier in two directions, and positioning with respect to the image carrier is performed. An optical print head, a first substrate having a plurality of light emitting sources arranged in a line and electrode wiring for each of the plurality of light emitting sources, and a light beam from the plurality of light emitting sources on an irradiated surface A lens array that forms an image, a housing that holds the first substrate and the lens array in a predetermined arrangement relationship and that has an abutting portion that comes into contact with the face plate, and a plurality of light emitting sources according to image data. A drive control circuit that generates write data to be modulated and controls driving thereof, a signal wiring extending from the drive control circuit, a second substrate for holding the housing, and the second substrate as the substrate Plane and flat Biasing means for biasing the abutting portion of the housing against the face plate in such a direction as to irradiate the irradiated surface, and the second substrate has its substrate surface and the optical axis of the lens array. The optical print head is characterized in that the housing is held so that the electrode wiring and the signal wiring are connected to each other in parallel.

  According to the optical print head of the present invention, the drive control circuit is provided on the second substrate, and the second substrate holds the first substrate (a plurality of light emitting sources) and the lens array in a predetermined arrangement relationship. Since the housing to be held is held, the width of the optical print head can be reduced. In addition, the second substrate holds the housing and the electrode wiring on the first substrate and the signal wiring on the second substrate are connected, so that the plurality of light emitting sources and the drive control circuit are directly connected without going through a harness. Therefore, high-speed data transfer corresponding to high-density and high-speed writing can be realized. Further, the housing holds the first substrate (a plurality of light emitting sources) and the lens array in a predetermined arrangement relationship, and the second substrate is arranged so that the substrate surface of the housing is parallel to the optical axis of the lens array. And the biasing means biases the second substrate toward the irradiated surface in a direction parallel to the surface of the substrate and brings the abutting portion of the housing into contact with the face plate. In addition, the lens array can be easily positioned.

1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus according to the present invention. FIG. 2 is a perspective view showing a state where a face plate supports a photosensitive drum in the image forming apparatus of FIG. 1. 1 is a perspective view showing a configuration of a first embodiment of an optical print head according to the present invention. It is sectional drawing which shows the structure of 1st Embodiment of the optical print head based on this invention. It is a disassembled perspective view which shows the relationship between the organic electroluminescent board | substrate, the lens array, and the housing in the optical print head of FIG. FIG. 4 is a block diagram illustrating a configuration of a drive control circuit in the optical print head of FIG. 3. It is a perspective view which shows the structure of another urging means in the optical print head of FIG. FIG. 2 is a perspective view showing a support state of the optical print head of the invention in the image forming apparatus of FIG. 1. It is the schematic which shows the arrangement | sequence state of the dot of the light beam on a photoconductor drum. It is sectional drawing which shows the structure of 2nd Embodiment of the optical print head based on this invention. It is a disassembled perspective view which shows the relationship between the organic electroluminescent board | substrate, prism mirror, lens array, and housing in the optical print head of FIG. It is sectional drawing which shows another structure of 2nd Embodiment of the optical print head based on this invention.

The configurations of the optical print head and the image forming apparatus according to the present invention will be described below.
(Image forming device)
FIG. 1 shows a schematic configuration of a main part of a tandem type color image forming apparatus 400 which is an embodiment of an image forming apparatus including an optical print head according to the present invention. Hereinafter, the symbols Y, M, C, and K are distinguished as portions corresponding to the colors Y (yellow), M (magenta), C (cyan), and K (black).

  The image forming apparatus 400 according to this embodiment is a tandem type color image forming apparatus in which a plurality of photosensitive drums 401 are arranged in parallel, and the photosensitive drum 401 corresponding to each color with respect to the transfer belt 405 has the transfer belt 405. Are arranged at equal intervals in the order of Y, M, C, and K from the top in the figure along the moving direction. The photosensitive drums 401 for the respective colors are formed to have the same diameter, and the members are sequentially arranged around the photosensitive drums 401 according to an electrophotographic process.

That is, around the photosensitive drum 401, as shown in the yellow section in FIG. 1, the charging roller 402 for charging the photosensitive drum 401 along the rotation direction of the photosensitive drum (the arrow direction in the drawing), the image The optical print head 100 (or 200) of the present invention, which is an exposure apparatus that emits a light beam based on data, and a developing unit 403 that attaches toner to a latent image formed by exposure of the optical print head 100 (200) and develops it. A first transfer unit 405a that transfers the toner image on the photosensitive drum 401 to the transfer belt 405, and a cleaning device 404 that scrapes the remaining toner on the photosensitive drum 401 after the transfer are disposed.
Further, as shown in FIG. 2, the photosensitive drum 401 is sandwiched in two left and right directions by a pair of face plates 502 and 503 that are both ends of the rotation shaft of the photosensitive drum 401 as a part of the frame of the image forming apparatus 400. Is held.
This is the same configuration for each color.

  As a result, yellow, magenta, cyan, and black toner images formed based on the image information of each color are sequentially superimposed on the transfer belt 405 to form a color toner image.

  The transfer belt 405 is provided with a position shift detection sensor 409, and the position shift of each color toner image superimposed on the transfer belt 405 is determined from the center of the image and the width direction (main scanning direction) of the transfer belt 405. Are detected at three points on the front side and the back side, which are both end portions.

  Here, the recording paper is supplied from the paper cassette 406 along the conveyance path 407, and the color toner image on the transfer belt 405 is transferred to the recording paper by the second transfer unit 405 b, and then the toner image is transferred by the fixing unit 408. It is fixed on the recording paper and discharged.

  As described above, the image forming apparatus of the present invention is equipped with the optical print head 100 (200) corresponding to high-density and high-speed image recording with a narrow width as will be described later. It is possible to provide an image forming apparatus that can be reduced in diameter and that is small and lightweight, and that is compatible with high-quality image recording. Further, as will be described later, in the optical print head 100 (200), the drive circuit for driving the light emission source and the write control circuit are mounted on the same printed circuit board as the drive control circuit, whereby the harness in the apparatus is reduced. The present invention is simplified, and an image forming apparatus with good assemblability can be provided.

(Optical print head)
FIG. 3 is a perspective view showing the configuration of the first embodiment of the optical print head according to the present invention. FIG. 4 is a cross-sectional view orthogonal to the main scanning direction. In FIG. 3, the housing 106 is a perspective view so that the inside of the housing 106 can be seen.

  The optical print head 100 is an optical print head in which both end portions in the longitudinal direction are brought into contact with the face plates 502 and 503 of the image forming apparatus 400 to perform positioning with respect to the photosensitive drum 401, as shown in FIGS. Further, an organic electroluminescence (EL) substrate 101 which is a first substrate having a plurality of light emission sources 102 arranged in a line and an electrode wiring 104 for each of the plurality of light emission sources 102, and the plurality of light emission sources 102. The lens array 105 that forms an image of the light beam on the irradiated surface (the surface of the photosensitive drum 401), the organic EL substrate 101, and the lens array 105 are held in a predetermined arrangement relationship, and are in contact with the face plates 502 and 503. A housing 106 having an abutting portion 106a and write data for modulating the plurality of light emitting sources 102 in accordance with the image data are generated and driven. It has a signal line 151 extending from the drive control circuit 150 and the drive control circuit 150 for controlling includes a printed circuit board 107 which is a second substrate that holds the housing 106.

  Here, as shown in FIGS. 4A and 4B, the organic EL substrate 101 includes a transparent glass substrate 101b serving as a base, a plurality of light emitting sources 102 provided on the substrate surface of the glass substrate 101b, An electrode wiring 104 formed by patterning on the substrate surface and connected for each light source 102 and a sealing glass 103 for sealing the light source 102 are provided.

The light emission source 102 is a conventionally known organic EL element in which an organic layer is sandwiched between a cathode and an anode on a glass substrate 101b, for example, in the main scanning direction (rotational axis direction of the photosensitive drum 401). Is arranged. The light emission source 102 of the present embodiment is a bottom emission type organic EL element.
The light emitting source 102 may be a light emitting diode (LED).

  The electrode wiring 104 is connected to the cathode and anode of the light emitting source 102 which is an organic EL element. As shown in FIG. 4B, the electrode wiring 104 has an opening 104a through which a light beam emitted from the light source 102 toward the glass substrate 101b is formed in a portion where the light source 102 is formed. . The light emitting sources 102 and the openings 104a are formed corresponding to the number of pixels in the main scanning direction. For example, the adjacent dot pitch p corresponding to 1200 dpi is p = 21 μm, and the A3 width (297 mm) is about 14,000, A4. About 10,200 pieces are arranged in the width (216 mm).

  4B shows an example in which the light source 102 and the openings 104a are arranged in a line in the main scanning direction (left and right direction in the figure), and FIG. 4C shows the light source 102 and the openings 104a in the main scanning direction. Are arranged in two rows, and are arranged in a staggered pattern with a predetermined interval shifted in the sub-scanning direction (vertical direction in the figure). By arranging the light emitting sources 102 in a staggered manner, the interval between the adjacent light emitting sources 102 can be increased, and the aperture diameter can be increased.

  Thereby, the light emission emitted from the light source 102 passes through the opening 104a, then passes through the glass substrate 101b, and is emitted from the side opposite to the mounting surface of the glass substrate 101b. It becomes.

  The diffused light emitted from the light emitting surface of the light emitting source 102 forms an image on a minute spot by the lens array 105 on the surface of the photosensitive drum 401, but the light emitting surface has the same magnification on the surface of the photosensitive drum 401. Therefore, if the size of the light emitting surface is not uniform for all the pixels, the image has uneven density. For example, in an optical print head in which 14,000 or more emission sources 102 having an A3 size width are arranged, if the beam spot diameters on the photosensitive drum 401 between the emission sources 102 are not uniform, Density unevenness and vertical streaks deteriorate image quality. As the dot size decreases with high density writing, this effect becomes more prominent. Therefore, in this embodiment, the light beam diameter is defined by the opening 104a so that the spot diameters are uniform in all the pixels. Therefore, the spot diameters of the light beams from the light emitting sources 102 that form an image on the irradiated surface of the photosensitive drum 401 can be made uniform, and the dot diameters after toner adhesion can be made uniform.

  The lens array 105 is formed by bundling cylindrical refractive index distribution type rod lenses having a refractive index distribution of a quadratic curve distribution in the radial direction in a two-row staggered arrangement. In this embodiment, a gradient index lens is used, but the same applies to a lens array in which spherical or aspherical lenses are arranged in an array.

The housing 106 is a frame that holds the organic EL substrate 101 and the lens array 105 so that the light emitting surface of the light source 102 and the surface of the photosensitive drum 401 are in a conjugate relationship. For example, as shown in FIG. 5, the organic EL substrate 101 and the lens array 105 are fitted into the frame of the housing 106 so that the emission surface of the organic EL substrate 101 and the incident surface of the lens array 105 face each other, and the respective surfaces are fitted into the housing. The spacer is positioned in contact with the spacer portion in 106 so as to be held integrally.
The housing 106 has convex abutting portions 106a projecting toward the photosensitive drum 401 that come into contact with the face plates 502 and 503 at both ends in the longitudinal direction (main scanning direction).

  The printed circuit board 107 has a drive control circuit 150, which is a one-chip semiconductor element, a signal wiring 151 extended from the drive control circuit 150, and a contact provided at an end of the signal wiring 151 on the substrate surface. 152.

  As shown in FIG. 6, the drive control circuit 150 is connected to the writing control ASIC 150a to which the image data and the dot positional deviation data from the positional deviation detection sensor 409 are input, and the writing control ASIC 150a is connected to the image data for each line. A line buffer 150b that is expanded and temporarily stored, a drive IC 150c that receives a signal from the write control ASIC 150a and outputs a control signal to the organic EL substrate 101 side, and a memory 150m that stores light amount correction data.

  The write control ASIC 150 a is a control circuit that outputs a signal for controlling the light emission timings of the plurality of light emission sources 102. Specifically, the write control ASIC 150a calculates the light emission timings of the plurality of light emission sources 102 using the line-by-line image data from the line buffer 150b as the write data for each pixel, and from the dot position shift data from the position shift detection sensor 409. The sub-scan for each light source 102 is obtained so as to obtain the inclination and curvature of the pixel array in the belt conveyance direction, so-called sub-scanning direction, and to correct the inclination and curvature of the pixel array as the inclination and curvature of the pixel array on the photosensitive drum 401. The light emission timing in the direction is corrected, and the result is output as a control signal.

  The driving IC 150c is an integration of switching thin film transistors (TFTs) for driving the light emitting source 102, which is an organic EL element, provided for each pixel, and a control signal from the write control ASIC 150a. The current applied to the light source 102 is controlled based on preset light amount correction data stored in the memory 150m. At this time, the amount of light beam emitted from the opening 104a is made uniform in each pixel.

  Here, the housing 106 is arranged so that the emission surface of the organic EL substrate 101, that is, the substrate surface of the glass substrate 101b on which the plurality of light emission sources 102 are mounted, stands upright with respect to the substrate surface of the printed circuit board 107. Mounted on the printed circuit board 107. At this time, the printed circuit board 107 has its substrate surface parallel to the optical axis of the lens array 105.

  At the same time, the electrode wiring 104 on the organic EL substrate 101 and the signal wiring 151 on the printed circuit board 107 are connected. Specifically, when the housing 106 is mounted on the printed circuit board 107, the electrode wiring 104 on the glass substrate 101b comes into contact with the contact 152 as shown in FIG. -Connection of the contact 152-signal wiring 151 allows the light emitting source 102 and the drive control circuit 150 to be directly connected without using a harness.

  As described above, the drive control circuit 150 is provided on a substrate (printed substrate 107) different from the organic EL substrate 101, and the printed circuit board 107 includes the organic EL substrate 101 (that is, the plurality of light emitting sources 102) and the lens array 105. Since the housing 106 is held in a predetermined arrangement relationship, the optical print head 100 can be narrowed. Note that the glass substrate 101b in the organic EL substrate 101 may be set to a predetermined thickness, and the glass substrate 101b may be directly brought into contact with the incident surface of the lens array 105 for positioning, thereby depending on the accuracy of the housing 106. Accordingly, the conjugate length between the position of the light emitting source 102 (light emitting point position) and the irradiated surface (the surface of the photosensitive drum 401) can be stably maintained, and light corresponding to high-quality image recording without unevenness in density. A print head can be provided.

  Further, since the printed circuit board 107 holds the housing 106 and the electrode wiring 104 on the organic EL substrate 101 and the signal wiring 151 on the printed circuit board 107 are connected, the plurality of light emitting sources 102 and the drive control circuit 150 are connected via a harness. Because it is directly connected, high-speed data transfer corresponding to high-density and high-speed writing can be realized. Accordingly, since the modulation timing of each light source 102 can be controlled in real time according to the dot position deviation information on the transfer belt, an optical print head compatible with high-quality image recording can be provided.

  Further, as shown in FIG. 3, the printed circuit board 107 is provided with the housing 106 of the printed circuit board 107, the drive control circuit 150, etc. on the main surface of the channel-shaped support member 111 having a U-shaped section formed by sheet metal processing. It is held on the support member 111 in such a manner that the surface opposite to the contact surface is brought into contact. Specifically, the guide pins 110 are placed in the longitudinal direction of the printed circuit board 107 in a state where the printed circuit board 107 is placed on the main surface of the support member 111 and the optical axis of the lens array 105 is parallel to the main surface of the support member 111. It is fixed to the support member 111 so as to pass through each of the long holes 107a extending in the direction toward the irradiated surface provided on both sides in the (main scanning direction). Thus, the printed circuit board 107 is mounted so as to be movable on the main surface of the support member 111 using the guide pins 110 as a guide in the length direction of the long holes 107a (that is, the optical axis direction of the lens array 105).

  The optical print head 100 also includes urging means that urges the printed circuit board 107 toward the irradiated surface in a direction parallel to the surface of the printed circuit board 107 to abut the abutting portion 106a of the housing 106 against the face plates 502 and 503. . 3, the torsion spring 109 is inserted into the guide pin 110, one end of the torsion spring 109 is engaged with the printed circuit board 107, and the other end is erected on the main surface of the support member 111. The urging means is engaged with the protrusion 111a. As a result, the torsion spring 109 presses the printed circuit board 107 toward the support member 111 and urges the printed circuit board 107 to always be pressed against the irradiated surface (photosensitive drum 401) with reference to the support member 111. The abutting portion 106a of the housing 106 comes into contact with the notches 502a and 503a (FIG. 2) of the face plates 502 and 503 that pivotally support the photosensitive drum 401, and a plurality of the abutting portions (photosensitive drum 401) with respect to the irradiated surface (photosensitive drum 401). The positions of the light source 102 and the lens array 105 are determined.

FIG. 7 shows another configuration of the urging means.
Here, in FIG. 7, the configuration of the organic EL substrate 101, the lens array 105, the housing 106, and the printed circuit board 107 and the assembly of these are the same as those shown in FIG. Is different from that shown in FIG.

  First, as shown in FIG. 7, the printed circuit board 107 includes a housing 106 of the printed circuit board 107, a drive control circuit 150, and the like on the main surface of a channel-shaped support member 111 ′ having a U-shaped cross section formed by sheet metal processing. The surface opposite to the provided surface is fixed by adhesion or the like. The support member 111 ′ has cutout holes 119 at both corners in the longitudinal direction (main scanning direction) and at the corner opposite to the irradiated surface.

  In the optical print head 100 having such a configuration, the torsion spring 121 is attached to the guide pins 120 that are erected on the side plates 301 and 302 (FIG. 8) that are members constituting the image forming apparatus 400 and hold the optical print head 100. Is inserted, one end of the torsion spring 121 is engaged with the cutout hole 119 of the support member 111 ′, and the other is engaged with the projection 122 erected on the side plates 301 and 302 to serve as a biasing means. Thus, the torsion spring 121 urges the printed circuit board 107 to be always pressed against the irradiated surface (photosensitive drum 401) via the support member 111 ′ with the side plates 301 and 302 as a reference. The abutting portion 106a of the housing 106 comes into contact with the notches 502a and 503a (FIG. 2) of the face plates 502 and 503 that pivotally support the drum 401, and a plurality of light emitting sources for the irradiated surface (photosensitive drum 401). The positions of 102 and the lens array 105 can be easily determined.

  By the way, as shown in FIG. 8, the structure frame of the image forming apparatus 400 includes a bottom plate 303 and side plates 301 and 302 erected on the bottom plate 303, and the optical print head 100 (or 200 described later) is provided. The both ends in the longitudinal direction of the support member 111 (or 111 ′) are supported by the side plates 301 and 302, thereby being supported at predetermined positions in the image forming apparatus 400. Specifically, rectangular holes 304 and 305 are formed in the side plates 301 and 302, respectively, and the end portion of the support member 111 (111 ′) is inserted into and supported by the rectangular holes 304 and 305, thereby supporting the optical print head 100 ( 200) positioning is performed.

  In FIG. 8, four sets of rectangular holes 304 and 305 are formed in the side plates 301 and 302, and the four optical print heads 100 (200) form four photosensitive members of the image forming apparatus 400 by the rectangular holes 304 and 305. The relative arrangement relationship is maintained so as to correspond to each of the drums 401 (FIG. 1).

  Here, the support member 111 (111 ') has an inclination adjusting means for adjusting the inclination of the printed board 107 with respect to the irradiated surface (the surface of the photosensitive drum 401) in the portion supported by the rectangular holes 304 and 305. That is, first, as shown in FIG. 3 (or FIG. 7), the side that supports the support member 111 (111 ′) among the open ends of the rectangular holes 304 and 305 of the side plates 301 and 302 (the lower side in the figure) ) Is formed on the end portion that protrudes in the sub-scanning direction (upward in the drawing), and the coil spring 115 is fitted into the projection portion 116, and the coil spring 115 has rectangular holes 304 and 305. Each end of the support member 111 (111 ′) to be inserted is supported and urged in one direction in the sub-scanning direction (from the bottom to the top in the figure). At this time, in the rectangular hole 304 of the left side plate 301 in the drawing, the adjusting screw 113 is placed at the end of the side (upper side in the drawing) opposite the side that supports the support member 111 (111 ′) among the opening ends. A bending portion 114 having a screw hole for screwing is provided, and the tip of the adjustment screw 113 screwed into the screw hole abuts on the upper surface of the support member 111 (111 ′) biased by the coil spring 115. ing. On the other hand, in the rectangular hole 305 of the right side plate 302 in the figure, a coil spring 115 is attached to the end of the opening end that faces the side that supports the support member 111 (111 ′) (upper side in the figure). Protrusions 117 that abut at two points on the upper surface of the biased support member 111 (111 ′) are provided. Therefore, the support member 111 (111 ′) is sandwiched between the coil spring 115 urged by the end on the side plate 301 and the tip of the adjustment screw 113, and the coil spring 115 urged by the end on the side plate 302 side and the protrusion 117. It is held in a state sandwiched between.

  At this time, when the screwing amount of the adjustment screw 113 on the side plate 301 side into the screw hole of the bent portion 114 is changed, the position of the tip of the adjustment screw 113 is changed in the sub-scanning direction. The position in the sub-scanning direction of the support member 111 (111 ′) with which the tip of 113 is in contact changes while being supported by the coil spring 115. On the other hand, on the side plate 302 side, the end of the support member 111 (111 ') is held at a fixed position while being sandwiched between the coil spring 115 and the protrusion 117. Therefore, by adjusting the screwing amount of the adjusting screw 113, the inclination in the sub-scanning direction with respect to the irradiated surface of the printed circuit board 107 integrated with the support member 111 (111 ') can be adjusted.

  Such inclination adjusting means is provided in each of the four optical print heads 100 (200) of the image forming apparatus 400, and between the lines formed on the photosensitive drum 401 by the four optical print heads 100 (200). Can be corrected.

  That is, in the tandem color image forming apparatus, a plurality of independent optical print heads 100 (200) are used in accordance with each color. Therefore, adjacent to each organic EL substrate 101 due to a manufacturing error, the light beam is adjacent. When the dot pitch p varies, the full width L in the main scanning direction becomes different. Now, assuming that the ideal adjacent dot pitch p0 and the total width are L0, for example, if the adjacent dot pitch p is shifted by only 0.1%, the error ΔL of the total width corresponding to the A3 width becomes 300 μm, and each color toner image Is a level that can be visually discerned, leading to degradation of image quality (FIG. 9A).

  Therefore, in the present invention, the screw amount of the adjusting screw 113 provided in the support member 111 (111 ′) of the optical print head 100 (200) is adjusted in order to make the positional deviation not more than 50 μm, which cannot be visually discerned. The optical print head 100 (200) is tilted in the sub-scanning direction by an angle θ toward the upstream side opposite to the rotation direction of the photosensitive drum 401, and the adjacent dot pitch projected on the main scanning line is ideally adjacent. The dot pitch p0 is set (FIG. 9B).

  At this time, the tilt of the optical print head 100 (200) causes a shift in the sub-scanning direction of the pixel array. As described above, the drive control circuit 150 (250 described later) sequentially delays the light emission timing of each pixel. By doing so, the dot position can be corrected so as to be aligned on the main scanning line. For example, since the deviation in the sub-scanning direction of the final pixel due to the inclination by the angle θ is (L + ΔL) sinθ, the emission timing can be delayed by (L + ΔL) sinθ / v with respect to the starting pixel. That's fine. Note that v is the transfer belt conveyance speed. Similarly, the delay amount of the light emission timing may be set for any n-th pixel.

  As described above, in each of the optical print heads 100 (200), even if there is a variation in the inclination or arrangement pitch of the plurality of light emitting sources 102, the arrangement of dots formed on the irradiated surface of the photosensitive drum 401 Since the images written by the plurality of optical print heads 100 (200) can be accurately superimposed, high-quality image recording without color misregistration can be realized.

  As described above, in the present invention, a substrate (organic EL substrate 101) on which a plurality of light emitting sources 102 are mounted on a printed circuit board 107 on which a writing control circuit is formed is in a plane perpendicular to the substrate surface or a plane parallel to the substrate surface. Even if the write control circuit is mounted on the printed circuit board 107 by connecting the wiring without passing through the harness and positioning the sub-scanning direction with respect to the circuit board surface of the printed circuit board 107 as a reference, It was made not to become an obstacle to narrowing the print head. Furthermore, it is possible to integrate the drive circuit of the light source and the write control circuit on one chip to form an ASIC.

FIG. 10 is a cross-sectional view perpendicular to the main scanning direction showing the configuration of the second embodiment of the optical print head according to the present invention.
The optical print head 200 is an optical print head in which both end portions in the longitudinal direction are brought into contact with the face plates 502 and 503 of the image forming apparatus 400 to perform positioning with respect to the photosensitive drum 401. As shown in FIG. An organic electroluminescence (EL) substrate 201 which is a first substrate formed by forming a plurality of light emitting sources 202 arranged in a line on a substrate 201b and an electrode wiring 204 for each of the plurality of light emitting sources 202; A predetermined arrangement of a lens array 205 that forms an image of a light beam from the light source 202 on the irradiated surface (the surface of the photosensitive drum 401), an organic EL substrate 201, a prism mirror 208 that is a reflection mirror, and a lens array 205. A housing 206 having an abutting portion 206a which is held in a relationship and abuts against the face plates 502 and 503, and image data In response, the second light source has a drive control circuit 250 for generating write data for modulating the plurality of light emitting sources 202 and controlling the drive thereof, and a signal wiring 251 extending from the drive control circuit 250, and holding a housing 206. And a printed circuit board 207 which is a circuit board.

  Here, the organic EL substrate 201 includes a transparent glass substrate 201b serving as a base, a plurality of light emission sources 202 provided on the substrate surface of the glass substrate 201b, and a pattern formed on the substrate surface and connected to each of the light emission sources 202. Electrode wiring 204 and sealing glass 203 for sealing the light emitting source 202 are provided.

  The light emission source 202 is a conventionally known organic EL element in which an organic layer is sandwiched between a cathode and an anode on a glass substrate 201b, for example, in the main scanning direction (rotational axis direction of the photosensitive drum 401). Is arranged. The light emitting source 202 of this embodiment is a bottom emission type organic EL element. The light source 202 may be a light emitting diode (LED).

  The electrode wiring 204 is connected to the cathode and the anode of the light emitting source 202 that is an organic EL element. Similar to the first embodiment, the electrode wiring 204 is formed on the portion where the light emitting source 202 is formed from the light emitting source 202 to the glass substrate 201b side. An opening through which the emitted light beam passes is formed.

  Further, the housing 206 holds the organic EL substrate 201, the prism mirror 208, and the lens array 205 through the prism mirror 208 so that the light emitting surface of the light source 202 and the surface of the photosensitive drum 401 are in a conjugate relationship. Is the body. For example, as shown in FIG. 11, the housing 206 has openings on the lower side and the side surface, and has a space such as an L-shaped elbow tube in a cross section that connects the opening on the lower side to the opening on the side surface. The organic EL substrate 201 is attached to the lower opening of the housing 206 with its emission surface facing upward, and the incident surface is directly bonded to the emission surface of the organic EL substrate 201 and emitted upward from the organic EL substrate 201. A prism mirror 208 that bends the light beam to be parallel to the substrate surface of the printed circuit board 207 and a lens array 205 whose incident surface is directly joined to the exit surface of the prism mirror 208 are positioned and integrated in the housing 206. Is retained. Therefore, in the organic EL substrate 201, the prism mirror 208, and the lens array 205 held in the housing 206, the light beam emitted upward from the organic EL substrate 201 is bent by the prism mirror 208 in a right angle direction (right direction in FIG. 10). Then, the light enters the lens array 205 and is emitted as it is in the optical axis direction of the lens array 205.

  In addition, since the emission surface of the organic EL substrate 201-the incident surface of the prism mirror 208 and the emission surface of the prism mirror 208-the incident surface of the lens array 205 are in direct contact with each other, the light emission source 202 is used regardless of the accuracy of the housing 206. The conjugate length between the position (light emitting point position) and the irradiated surface (the surface of the photosensitive drum 401) can be stably maintained, and an optical print head compatible with high-quality image recording without density unevenness can be provided. .

  The housing 206 has convex abutting portions 206a projecting toward the photosensitive drum 401 that come into contact with the face plates 502 and 503 at both ends in the longitudinal direction (main scanning direction).

  The printed circuit board 207 includes a drive control circuit 250, which is a one-chip semiconductor element, and a signal wiring 251 extended from the drive control circuit 250 on the substrate surface (on the upper substrate surface in FIG. 10). Have.

  The drive control circuit 250 conforms to the configuration shown in FIG. 6, and is connected to the write control ASIC 150a to which image data and dot position shift data from the position shift detection sensor 409 are input, and to the image data connected to the write control ASIC 150a. For each line, a line buffer 150b for temporarily storing, a drive IC 150c for receiving a signal from the write control ASIC 150a and outputting a control signal to the organic EL substrate 201 side, and a memory 150m for storing light amount correction data Have. Details of each part are as shown in the first embodiment.

  Here, the housing 206 is arranged so that the emission surface of the organic EL substrate 201, that is, the substrate surface of the glass substrate 201b on which the plurality of light emitting sources 202 are mounted is parallel to the substrate surface of the printed circuit board 207. 207 is mounted. At this time, the substrate surface of the printed circuit board 207 and the optical axis of the lens array 205 are parallel. Accordingly, a light beam is emitted from the light emitting source 202 in a direction perpendicular to the substrate surface of the printed circuit board 207 (upward in the figure).

  At the same time, as shown in FIG. 10, when the mounting surface of the light emitting source 202 and the electrode wiring 204 on the organic EL substrate 201 is facing downward, and the organic EL substrate 201 is mounted on the printed board 207, it is provided on the printed board 207. The light emitting source 202 and the sealing glass 203 are fitted into the opening, and the lower substrate surface of the organic EL substrate 201 and the upper substrate surface of the printed circuit board 207 come into contact with each other. As a result, the electrode wiring 204 on the organic EL substrate 201 and the signal wiring 251 on the printed circuit board 207 are connected, and the light emission source 202 and the drive control circuit 250 are directly connected without going through the harness.

  As described above, the drive control circuit 250 is provided on a substrate (printed substrate 207) different from the organic EL substrate 201, and the printed substrate 207 includes the organic EL substrate 201 (that is, the plurality of light emitting sources 202), the prism mirror 208, and the lens. Since the housing 206 that holds the array 205 in a predetermined arrangement relationship is held, the width of the optical print head 200 can be reduced.

  In addition, since the printed circuit board 207 holds the housing 206 and the electrode wiring 204 in the organic EL substrate 201 and the signal wiring 251 in the printed circuit board 207 are connected, the plurality of light emitting sources 202 and the drive control circuit 250 are connected via a harness. Because it is directly connected, high-speed data transfer corresponding to high-density and high-speed writing can be realized. Therefore, since the modulation timing of each light source 202 can be controlled in real time according to the dot position deviation information on the transfer belt, an optical print head compatible with high-quality image recording can be provided.

  Similarly to the first embodiment, the optical print head 200 has support members 111 and 111 ′ (FIGS. 3 and 7), and the printed circuit board 207 is covered in a direction parallel to the substrate surface. There is provided urging means that urges the abutting portion 206a of the housing 206 against the face plates 502 and 503 by urging the irradiation surface side.

  As shown in FIG. 8, the optical print head 200 is supported at a predetermined position in the image forming apparatus 400 by supporting both end portions in the longitudinal direction of the support member 111 (or 111 ′) on the side plates 301 and 302. Is done. At this time, as in the first embodiment, the support member 111 (111 ′) is inclined with respect to the irradiated surface (the surface of the photosensitive drum 401) of the printed board 207 in the portion supported by the rectangular holes 304 and 305. Inclination adjusting means for adjusting is provided. Further, in response to the inclination of the optical print head 200, the drive control circuit 250 corrects the dot positions so that the light emission timings of the respective pixels are sequentially delayed and aligned on the main scanning line as described above. I do.

  Although the present invention has been described with the embodiments shown in the drawings, the present invention is not limited to the embodiments shown in the drawings, and other embodiments, additions, modifications, deletions, etc. Can be changed within the range that can be conceived, and any embodiment is included in the scope of the present invention as long as the effects and advantages of the present invention are exhibited.

For example, in the first and second embodiments, the case where the light emission sources 102 and 202 are bottom emission type organic EL elements has been described. However, the present invention is not limited to this, and the light emission sources 102 and 202 are the top emission type. It is good also as this organic EL element. FIG. 12 shows an example of the configuration.
In FIG. 12, the configuration of the organic EL substrate 201 is basically the same as that shown in FIG. 10, except that a light beam is emitted from a plurality of light emitting sources 202 in the direction opposite to the glass substrate 201b. . Therefore, the housing 206 holds the organic EL substrate 201 in a state where the light emission source 202 and the sealing glass 203 of the organic EL substrate 201 are fitted into the opening of the printed circuit board 207.
Here, also in FIG. 12, the housing 206 is such that the emission surface of the organic EL substrate 201, that is, the substrate surface of the glass substrate 201 b on which the plurality of light emission sources 202 are mounted is parallel to the substrate surface of the printed circuit board 207. In addition, it is mounted on the printed circuit board 207. At this time, the substrate surface of the printed circuit board 207 and the optical axis of the lens array 205 are parallel.
At the same time, as shown in FIG. 12, when the mounting surface of the light emitting source 202 and the electrode wiring 204 on the organic EL substrate 201 is facing upward, and the organic EL substrate 201 is mounted on the printed circuit board 207, the upper side of the organic EL substrate 201 is And the lower substrate surface of the printed circuit board 207 come into contact with each other, the electrode wiring 204 on the organic EL substrate 201 and the signal wiring 251 on the printed circuit board 207 are connected, and the light emitting source 202 and the drive control circuit 250 are connected to the harness. It will be connected directly without going through.

100,200 Optical print head
101, 201 Organic EL substrate 101b, 201b Glass substrate 102, 202 Light emission source 103, 203 Sealing glass 104, 204 Electrode wiring 104a Opening 105, 205 Lens array 106, 206 Housing 106a, 206a Abutting portion 107, 207 Printed substrate 107a Long hole 109 Torsion spring 110 Guide pin 111, 111 'Support member 111a Protrusion 113 Adjustment screw 114 Bending portion 115 Coil spring 116, 117 Protrusion portion 119 Notch hole 120 Guide pin 121 Torsion spring 122 Protrusion 150, 250 Drive control circuit 150a Write control ASIC
150b line buffer 150c driving IC
150 m Memory 151, 251 Signal wiring 152 Contact 208 Prism mirror 301, 302 Side plate 303 Bottom plate 304, 305 Rectangular hole 400 Image forming device 401 Photosensitive drum 402 Charging roller 403 Development unit 404 Cleaning device 405 Transfer belt 405a First transfer means 405b First 2 Transfer means 406 Paper cassette 407 Transport path 408 Fixing unit 409 Position shift detection sensor 502, 503 Face plate 502a, 503a Notch

JP 2010-194928 A JP 2010-115910 A

Claims (8)

An optical print head in which positioning with respect to the image carrier is performed by contacting both end portions in the longitudinal direction with a face plate of an image forming apparatus that holds the image carrier in at least two directions.
A first substrate having a plurality of light emitting sources arranged in a line and an electrode wiring for each of the plurality of light emitting sources;
A lens array that images light beams from the plurality of light emitting sources on an irradiated surface;
A housing that holds the first substrate and the lens array in a predetermined arrangement relationship and has a contact portion that comes into contact with the face plate;
A drive control circuit for generating write data for modulating the plurality of light emitting sources according to image data and controlling the drive; and a signal wiring extending from the drive control circuit; A substrate,
Urging means for urging the second substrate toward the irradiated surface side in a direction parallel to the substrate surface and bringing the abutting portion of the housing into contact with the face plate;
An optical print head, wherein the second substrate holds the housing so that the substrate surface is parallel to the optical axis of the lens array, and the electrode wiring and the signal wiring are connected.   The said 1st board | substrate is arrange | positioned so that the board | substrate surface in which these light emission sources are mounted may become perpendicular | vertical with respect to the board | substrate surface of a said 2nd board | substrate. Optical print head. The first substrate is disposed such that a substrate surface on which the plurality of light emitting sources are mounted is parallel to a substrate surface of the second substrate,
2. The optical print head according to claim 1, wherein the housing has a reflection mirror that bends light beams emitted from the plurality of light emitting sources toward the lens array. A support member for supporting the second substrate and having both longitudinal ends supported by side plates of the image forming apparatus;
4. The optical print head according to claim 1, wherein the support member includes an inclination adjusting unit that adjusts an inclination of the second substrate with respect to the irradiated surface. 5.   5. The optical print head according to claim 4, wherein the drive control circuit modulates the plurality of light emission sources in accordance with a tilt amount of the second substrate by the tilt adjusting unit.   6. The optical print head according to claim 1, wherein the electrode wiring on the first substrate has an opening for regulating a beam diameter of a light beam emitted from a light source. The plurality of light emission sources are bottom emission type organic electroluminescence elements,
The optical print head according to claim 6, wherein light beams from the plurality of light emitting sources are emitted through the first substrate.   An electrophotographic image forming apparatus comprising the optical print head according to claim 1.