JP4331459B2 - Optical writing apparatus and image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical writing apparatus that irradiates image light onto a surface of an image carrier from a plurality of light emitters, and an electrophotographic image forming apparatus to which the optical writing apparatus is applied.
[0002]
[Prior art]
In an electrophotographic image forming apparatus, an electrostatic latent image is formed by irradiating the surface of an image carrier with image light based on image data, a charging step for uniformly applying charges to the surface of the image carrier such as a photosensitive drum. An exposure process to form, a development process to visualize the electrostatic latent image on the surface of the image carrier into a developer image, and a transfer process to transfer the developer image from the surface of the image carrier to a recording medium are sequentially performed. . The unfixed developer image on the recording medium after the transfer process is firmly fixed on the surface of the recording medium in a fixing process in which the recording medium is heated and pressed together with the recording medium, thereby forming a clear image.
[0003]
Conventionally, as an optical writing device used in the exposure process in such an electrophotographic image forming apparatus, for example, as shown in FIG. 6, a laser beam which is image light emitted from a laser light emitting element is rotated and rotated. Laser scanning units 301a to 301d that deflect by a mirror or the like and scan in the main scanning direction to form an electrostatic latent image on the image carrier have been widely used.
[0004]
Since such a laser scanning unit deflects a laser beam emitted from one laser light emitting element at a wide angle, a large optical system with a long optical path length is required, and the apparatus is increased in size and cost. It cannot be applied to an image forming apparatus that is strongly demanded to be reduced in size and cost, such as a home-use image forming apparatus.
[0005]
Therefore, as shown in FIG. 5, solid scanning optical writing devices 201a to 201d in which light emitting elements such as LEDs and ELs are arranged in an array are used in the exposure process of the image forming apparatus. By using such an optical writing device, the image forming apparatus can be significantly reduced in size and cost, and the rotating mechanism can be eliminated so that noise can be reduced. .
[0006]
In the image forming apparatuses 200 and 300 shown in FIGS. 5 and 6, 202a to 202d are developing units (imaging devices), 203a to 203d are photosensitive drums, 204a to 204d are cleaners, and 205a to 205d are chargers. , 206a to 206d are transfer units.
[0007]
In such a solid scanning optical writing apparatus, for example, in order to form an A3 width image with a resolution of 600 dpi, about 7000 light emitting elements are arranged on one line. A drive circuit that controls the amount of light emitted and the light emission timing is required, and the drive circuit is mounted on a substrate on which the light emitting element is mounted (see Patent Documents 1 and 2).
[0008]
[Patent Document 1]
Japanese Patent Laid-Open No. 02-196476
[Patent Document 2]
Japanese Patent Laid-Open No. 02-062256
[Problems to be solved by the invention]
However, when the light emitting element that irradiates light in the normal direction of the substrate surface and the drive circuit configured in a relatively wide range on the substrate surface are mounted on the same substrate, as shown in FIG. The substrate is formed in a state extending in a direction orthogonal to the optical axis of the image light emitted from the image forming apparatus, and the optical axis of the image light in the image forming apparatus is substantially orthogonal to the sub-scanning direction, which is the conveyance direction of the recording medium; Since the space in the main scanning direction in the image forming apparatus is limited, the substrate of the optical writing device must be enlarged in the sub-scanning direction, and the optical writing device can be reduced in the sub-scanning direction. There is a problem that cannot be done.
[0009]
In addition, the conventional solid scanning optical writing device is not suitable for writing a multi-valued image due to a large light amount error of each light emitting element, and has been used only for an image forming device that forms a single color image. . However, in recent years, the technical progress of the solid scanning optical writing device has been remarkable in response to the demand for miniaturization and speeding up of the color image forming apparatus, and the solid scanning optical light is also applied to the image forming apparatus that forms color images. Writing devices are starting to be used.
[0010]
In order to increase the speed of the color image forming apparatus, as shown in FIGS. 5 and 6, a plurality of image forming stations configured by a plurality of functional units including the optical writing apparatus are arranged side by side in the sub-scanning direction. The tandem color image forming apparatus is usually provided with four image forming stations. Since the size of each functional unit constituting the image forming station affects the overall size of the image forming apparatus, the miniaturization of the optical writing device, which is one of the functional units, realizes the miniaturization of the color image forming apparatus. Is particularly important in doing so.
[0011]
An object of the present invention is to provide an optical writing device capable of reducing the size of the image forming apparatus by efficiently arranging the components constituting the solid scanning optical writing device, and an image provided with the optical writing device. It is to provide a forming apparatus.
[0012]
[Means for Solving the Problems]
  (1) In an optical writing apparatus that irradiates image light based on image data on the surface of an image carrier between a charger and a visualization device in an image forming apparatus that performs electrophotographic image formation.
  Multiple surface-emitting light emitting elements mounted in an arrayA head array and a lens array for imaging the image light emitted from the light emitting element on the surface of the image carrierA writing head and a driving circuit board on which a driving circuit for driving the light emitting element is mounted;PreparationThe drive circuit board is connected to the write head.AndForm independently and
  A support member that supports the drive circuit board so that a main surface thereof is positioned between the charger and the visualization device so as to be substantially parallel to an outer wall on the charger side of the visualization device; A support member that supports the head unit substrate and the lens array so that the optical axis of the image light passes through the rotation center of the image carrier,
  The support member includes a first block and a second block that hold both ends of the write head, a connecting member that connects the first block and the second block, and holds the drive circuit board, The connecting member is made of a material that is more easily deformed than the first block, the second block, and the write head.
[0013]
In this configuration, the drive circuit board on which the drive circuit for driving the write head is mounted and the head part board on which the light emitting element of the write head is mounted are formed independently of each other. Therefore, the substrate surface of the drive circuit board can be set at an arbitrary angle with respect to the optical axis of the image light emitted from the writing head.
[0014]
In addition to the optical writing device, functional units such as a charger, a developing unit, a transfer device, and a cleaner are disposed around the image carrier in the image forming apparatus. In order to carry out the exposure process, the development process and the transfer process before the charge applied to the surface of the image carrier by the charger is attenuated, the image should be irradiated in the normal direction. The charging position, exposure position, development position, and transfer position on the surface of the carrier need to be as close as possible. In general, the transfer position is formed at a position below the surface of the image carrier. In particular, in a tandem type image forming apparatus, the transfer position is formed at a position having a horizontal line as a tangent line on the surface of the image carrier. Further, in order to efficiently use the developer stored in the developing device, the developing device should be formed long in the vertical direction.
[0015]
In order to satisfy all of these conditions, the optical axis direction of the image light emitted from the optical writing device needs to be inclined from the vertical direction to the developing device side. In this case, if the substrate surface of the drive circuit board is arranged in parallel to the optical axis of the image light, the substrate area necessary for the drive circuit board cannot be secured because it interferes with the developing device. On the other hand, if the angle between the substrate surface of the drive circuit board and the optical axis of the image light is increased, the board area necessary for the drive circuit board cannot be secured due to interference with other functional units. Therefore, it is necessary to incline the substrate surface of the drive circuit board with respect to the optical axis of the image light by an angle in consideration of the positional relationship with other functional units.
[0016]
In this configuration, since the head unit substrate on which the light emitting element of the writing head that irradiates image light is mounted and the drive circuit substrate are formed separately, the substrate surface of the drive circuit substrate is connected to other functional units. It can be inclined with respect to the optical axis of the image light at an angle in consideration of the positional relationship.
[0021]
  (2)An image forming apparatus comprising: an image carrier; and a transfer device that transfers a visible image from the image carrier to a recording medium.
  Furthermore, (1)An optical writing device according to claim 1,AboveBy image light irradiation from optical writing deviceAboveA developing device for visualizing the electrostatic latent image formed on the image carrier,By the transfer deviceA visible image is transferred from the image carrier to a recording medium.
[0022]
In this configuration, the drive circuit board in the optical writing device arranged adjacent to the visualization device around the image carrier is formed independently from the head unit substrate on which the light emitting element of the writing head is mounted. Is done. Therefore, the board surface of the drive circuit board can be inclined with respect to the optical axis of the image light at an angle that considers the positional relationship with other functional units.
[0025]
  (3) An image forming apparatus in which a plurality of image carriers are juxtaposed in the moving direction of the recording medium together with the same number of optical writing devices and visualizing devices, and the drive circuit board is disposed between the visualizing devices. It is characterized by that.
[0026]
In this configuration, the optical writing device is disposed so that the substrate surface of the drive circuit substrate is substantially vertical in a narrow space between a plurality of visualization devices each formed with the vertical direction as the longitudinal direction. Is done. Therefore, the arrangement width of the optical writing device becomes narrower in the sub-scanning direction, which is the direction in which a plurality of visualization devices are arranged, and the image forming apparatus is downsized in the sub-scanning direction.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is an explanatory diagram showing a configuration of an image forming apparatus according to an embodiment of the present invention. The image forming apparatus 100 according to the embodiment of the present invention forms a multicolor or single color image on a predetermined recording medium such as paper based on image data supplied from the outside. Inside the image forming apparatus 100, image forming stations 11 a to 11 d, a transfer conveyance belt unit 8, a fixing unit 12, a paper feed tray 10, and a control unit 15 are provided. Further, above the inside of the image forming apparatus 100, a control unit 17 that controls and controls the operation of each unit, and an image processing unit 18 that performs predetermined image processing on image data input from the outside are provided. ing.
[0028]
The transfer / conveyance belt unit 8 is disposed at a substantially central portion inside the image forming apparatus 100, and the upper end portion of the endless transfer / conveyance belt 7 is made substantially horizontal by a driving roller 73, driven rollers 71 and tension rollers 72 and 74. It is stretched in a loop shape. The transfer conveyance belt 7 rotates in the direction of arrow B by the rotation of the drive roller 73, and conveys the recording paper that is electrostatically attracted to the outer surface in the upper portion of the loop. The transfer conveyance belt 7 is cleaned by a cleaner 9 at the lower portion of the loop. This is to remove the toner adhering to the photosensitive drums 3a to 3d, which will be described later, and prevent the back surface of the recording paper from being stained.
[0029]
The image forming stations 11 a to 11 d are arranged in parallel along the upper portion of the loop formed by the transfer conveyance belt 7. Each of the image forming stations 11a to 11d has the same configuration, and performs electrophotographic image formation based on image data of each color of black (K), cyan (C), magenta (M), and yellow (Y). Do. As an example, the image forming station 11a includes a charger 5a, an optical writing device 1a, a developing unit 2a, a transfer device 6a, and a cleaner 4a around the photosensitive drum 3a along the rotation direction of the photosensitive drum 3a. They are arranged in order.
[0030]
The photoconductive drum 3a has a photoconductive layer that generates a photoconductive action on its surface, and is supported so as to be rotatable in the direction indicated by the arrow in the figure. The charger 5a uniformly charges the surface of the photosensitive drum 3a to a predetermined potential by a roller-type or brush-type contact method or a charger method that performs corona discharge. The optical writing device 1a includes a writing head in which light-emitting elements such as EL or LED are arranged in an array in the rotation axis direction (main scanning direction) of the photosensitive drum 3a, and modulates based on K image data. The surface of the photosensitive drum 3a is exposed with the image light thus formed. Details of the optical writing device 1a will be described later. By exposure of image light from the optical writing device 1a, an electrostatic latent image is formed on the surface of the photosensitive drum 3a.
[0031]
The developing unit 2a supplies K toner to the surface of the photosensitive drum 3a on which the electrostatic latent image is formed, and visualizes the electrostatic latent image into a K toner image. The transfer device 6a is opposed to the photosensitive drum 3a with the upper portion of the loop formed by the transfer conveyance belt 7 interposed therebetween, and a high voltage having a polarity opposite to the charging polarity of the toner is applied to the transfer device 6a. As an example, the transfer device 6a is configured by covering a surface of a metal roller such as stainless steel having a diameter of 8 to 10 mm with a conductive elastic material made of EPDM, urethane foam, or the like. A high voltage is uniformly applied to the electrostatically adsorbed recording paper to transfer the toner image carried on the surface of the photosensitive drum 3a onto the surface of the recording paper. The transfer device 6a can also be configured in a brush shape. The cleaner 4a collects toner, paper dust, and the like remaining on the surface of the photosensitive drum 3a that has passed through the position facing the transfer device 6a.
[0032]
As described above, the image forming stations 11b to 11d perform image formation based on the image data of each color of C, M, and Y. Therefore, each of the optical writing devices 1b to 1d has each color of C, M, and Y. Image data is supplied, and each of the developing units 2b to 2d contains toner of C, M, and Y colors.
[0033]
The paper feed tray 10 stores paper used for image formation, and is detachably mounted below the image forming apparatus 100. Inside the image forming apparatus 100, the image is passed through the upper portion of the loop formed by the transfer conveyance belt 7 from the paper feed tray 10 and between the heating roller 31 and the pressure roller 32 in the fixing unit 12. The pickup roller 16, the registration roller 14, the flapper 34, and the paper discharge are provided between the paper discharge tray 33 mounted on one side of the forming apparatus 100 and the paper discharge tray 15 formed on the upper part of the image forming apparatus 100. A sheet transport path S is configured by the rollers 25 and the like.
[0034]
The paper discharge tray 33 stacks and stores recording paper with an image diameter in a face-up state with the image forming surface facing upward. The paper discharge tray 15 stacks and stores recording sheets having an image diameter in a face-down state with the image forming surface facing downward. The flapper 34 selectively switches the recording paper discharge position to the paper discharge tray 33 or the paper discharge tray 15.
[0035]
The pickup roller 16 is disposed on one end side of the paper feed tray 10 so as to face the uppermost surface of the paper stored in the paper feed tray 10, and guides the paper from the paper feed tray 10 to the paper transport path S one by one. The registration roller 14 temporarily stops the recording sheet fed from the sheet feeding tray 10 on the upstream side of the transfer conveyance belt 7 in the sheet conveyance path S, and then synchronizes with the rotation of the photosensitive drums 3a to 3d. It is guided to the transfer conveyance belt 7 at timing.
[0036]
That is, the registration roller 14 stops rotating at the timing when the recording paper is fed from the paper feed tray 10, and the front end of the recording paper is opposed to the photosensitive drums 3a to 3d and the transfer devices 6a to 6d. At the position, rotation is started at a timing that is carried on each of the photosensitive drums 3a to 3d and coincides with the leading edge of the developer image. At the time of full-color image formation, the K, C, M, and Y toner images carried on the photosensitive drums 3a to 3d are superimposed on each other on one recording sheet.
[0037]
The fixing unit 12 includes a heating roller 31 and a pressure roller 32. The heating roller 31 is controlled to a predetermined fixing temperature at which toner can be melted based on a signal from a temperature sensor (not shown), and the pressure roller 32 is in pressure contact with the heating roller 31 with a predetermined pressing force. The sheet on which the developer image has been transferred is heated and pressurized while passing through the fixing unit 12, and the developer image on the sheet is melted and firmly fixed on the surface of the sheet. The K, C, M, and Y developer images transferred onto one recording sheet at the time of full color image formation form a full color image by subtractive color mixing.
[0038]
At the time of full-color image formation, image formation is performed at all of the four image forming stations 11a to 11d. At the time of single-color image formation for forming a single-color image such as a monochrome image, among the four image forming stations 11a to 11d, Image formation is performed only in the image forming station corresponding to the image color to be processed.
[0039]
FIG. 2 is a diagram illustrating a configuration of a main part of the image forming apparatus, and illustrates a configuration and an arrangement state of the optical writing device. In this figure, the optical writing devices 1b and 1c, the developing units 2b and 2c, and the photosensitive drums 3b and 3c included in the image forming stations 11b and 11c are shown together with the developing unit 2d included in the image forming station 11d. The optical writing devices 1a to 1d included in each of the image forming stations 11a to 11d have the same configuration, and the optical writing devices 1a to 1d are described as the optical writing device 1 in the following description. However, descriptions of a to d are omitted as appropriate for the internal components and other functional units. The photosensitive drums 3b and 3c are also referred to as the photosensitive drum 3.
[0040]
The optical writing apparatus 1 includes a writing head 110 and a drive circuit board 120 that are separated from each other. The write head 110 includes a head unit substrate 112 on which an LED 113 that is a light emitting element is mounted, a lens array 114, and the like. Therefore, in the optical writing apparatus 1, the drive circuit board 120 is formed independently of the head part board 112 on which the LED 113 to be driven is mounted, and both are electrically connected via a flexible cable. It is connected.
[0041]
The LED 113 is lighted and driven according to image data read from the memory of the image processing unit 18 or image data transferred from an external device, and emits image light. The lens array 114 is, for example, a selfoc lens, and forms an image of the image light emitted from the LED 113 on the photosensitive drum 3. The writing head 110 forms an electrostatic latent image on the photosensitive drum 3 by image light based on the image data. The electrostatic latent image formed on the photosensitive drum 3 is visualized as a developer image by the toner supplied from the developing unit 2 and transferred onto the paper P.
[0042]
The optical axis of the image light of the writing head 110 facing the surface of the photosensitive drum 3 is a vertical line passing through the rotation center of the photosensitive drum 3 (a line perpendicular to both the main scanning direction and the sub-scanning direction). It has an angle of θ with respect to it. This is because the development process and the transfer process must be completed in a period in which the potential of the electrostatic latent image formed on the surface of the photosensitive drum 3 is not attenuated as much as possible, so that the exposure position of the image light is as close as possible to the transfer process position. This is because the outer diameter of the photosensitive drum 3 must be made as small as possible in order to reduce the size of the image forming apparatus 100. If the potential attenuation is not a problem and the demand for downsizing of the image forming apparatus 100 is weak, the outer diameter of the photosensitive drum 3 may be increased so that θ is zero.
[0043]
The drive circuit board 120 for driving the write head 110 to be lit is disposed so that the board surface thereof is substantially parallel to a vertical line passing through the rotation center of the photosensitive drum 3, and between the adjacent developing units 2 (for example, Between the developing unit 2c and the developing unit 2d) and substantially parallel to the outer walls 21 and 22 of the developing unit 2 on the optical writing device 1 side. Therefore, the angle θ ′ formed between the drive circuit board 120 and the optical axis of the image light of the write head 110 is formed by the optical axis of the image light of the write head 110 and a vertical line passing through the rotation center of the photosensitive drum 3. It substantially coincides with the angle θ. However, the angle θ ′ does not necessarily coincide with the angle θ, and is an angle determined by the inclination of the outer walls 21 and 22 of the developing unit 2.
[0044]
In the configuration shown in FIG. 2, the inclination of the inner wall 23 of the developing unit 2 can be increased, and an uneconomic state in which a part of the toner stored in the developing unit 2 remains unused. Trouble that does not occur.
[0045]
Thus, by making the drive circuit substrate 120 independent of the head portion substrate 112 of the write head 110, not only the write head 110 can be made small, but also a drive that requires a sufficient substrate area for mounting the drive circuit is required. The circuit board 120 can be arranged at an arbitrary angle regardless of the direction of the optical axis of the image light applied to the photosensitive drum 3. For this reason, by arranging the drive circuit board 120 in the space between the adjacent developing units 2 so as to be substantially parallel to the outer wall of the developing unit 2, this space can be formed narrowly, and the outer diameter of the photosensitive drum 3 can be reduced. Can be small. In addition, the arrangement interval D between the adjacent photosensitive drums 3 can be narrowed. In this embodiment, the outer diameter of the photosensitive drum 3 can be reduced by about 10 mm, and the interval between the photosensitive drums 3 can be reduced by about 10 mm. As a result, the distance from the photosensitive drum 3a of the most upstream image forming station 11a to the photosensitive drum 3d of the most downstream image forming station 11d is reduced by about 10 × 3 = 30 mm, and the sub-scan of the image forming apparatus 100 is performed. We were able to reduce the size of the direction sufficiently.
[0046]
FIG. 3 is a perspective view showing the configuration of the optical writing device. The optical writing device 1 includes a writing head 110 and a support unit 140 that supports the writing head 110 and is a support member of the present invention. The support unit 140 includes a first block 141, a second block 142, and a connecting member 143 that connects the first block 141 and the second block 142. For example, the first block 141 and the second block 142 are formed by molding using a resin containing glass fibers such as PPS (polyphenylene sulfide) or PPE (polyphenylene ether). Since these blocks 141 and 142 perform high-precision positioning of the write head 110, a material having a high strength and a small linear expansion coefficient is used.
[0047]
Further, since the second block 142 is located on the rear end side when the optical writing device 1 is inserted into the image forming apparatus 100, the second block 142 can be made larger than the first block 141. Considering the positional relationship, it is desirable to have a long and narrow shape, and therefore, PPS having a smaller linear expansion coefficient and higher strength is used. In this embodiment, resin is used in consideration of cost and productivity. However, when the strength is more important, it may be formed by aluminum die casting or the like.
[0048]
The connecting member 143 that connects the first block 141 and the second block 142 is a member processed by a press using an iron-based thin steel plate. In this example, a steel plate having a thickness of 0.6 mm is used for the connecting member 143. However, the connecting member 143 is not limited to a steel plate having this thickness, and depending on the material of the blocks 141 and 142, a thicker or thinner member may be used. Also good. Further, the connecting member 143 may be made of any material as long as it has lower rigidity than the first block 141, the second block 142, and the LED writing head 110.
[0049]
This example is characterized in that the connecting member 143 is configured to be a member that is most likely to be deformed in the optical writing device 1. Here, the fact that the deforming is likely to occur is used for the connecting member 143. The connecting member 143 is easily deformed by an external force, for example, when the elastic coefficient of the material to be formed is low and easily deformed, or when the shape of the connecting member 143 is formed so that the secondary moment of the section is small. . As long as the material of the connecting member 143 does not cause brittle fracture, the material is not limited to elastic deformation, and may be a material that immediately plastically deforms by an external force.
[0050]
FIG. 4 is a side view showing the configuration of the optical writing device. In the figure, the horizontal direction in the figure is the main scanning direction, and the direction perpendicular to the drawing is the sheet conveying direction. Here, the near side in the figure is the upstream side in the sheet conveying direction, and the far side in the figure is the downstream side in the sheet conveying direction.
[0051]
The connecting member 143 of the support unit 140 described above is fixed in a state where a part thereof is in contact with the metal frame 101 of the image forming apparatus 100. The drive circuit board 120 is attached to the connecting member 143 through a screw 123 while being shielded by the shield member 122. The drive circuit board 120 is attached to the shield member 122 so that a shield effect can be obtained when the ground line in the drive circuit board 120 is brought into contact with the shield member 122 by the screws 124 to be conductive. The drive circuit board 120 is covered with a shield cover member (not shown). The drive circuit board 120 is connected to the head part board 112 of the write head 110 via flexible cables 125 and 126, and supplies drive signals and power to the write head 110. . The drive circuit board 120 includes a connector 127 for connecting to the control unit 17 and the image processing unit 18 via a cable (not shown), and a connector 128 for connecting to the power source via a cable (not shown).
[0052]
As described above, the drive circuit board 120 is connected to the head part board 112 on which the LED 113 is mounted via the flexible cables 125 and 126. Therefore, even when the substrate surface of the drive circuit board 120 is tilted at an arbitrary angle with respect to the optical axis of the image light emitted from the LED 113 mounted on the head part board 112, the drive circuit board 120 and the head part substrate 112 are used. The electrical connection state can be maintained well. Further, when a failure occurs in one of the drive circuit board 120 or the head part board 112, only the failed one can be replaced and the other can be used continuously, and the components can be used efficiently.
[0053]
Further, since the drive circuit board 120 is fixed to the metal connecting member 143 constituting the support unit 140 via the shield member 122, and this connecting member 143 is fixed to the metallic frame 101, the drive circuit board is provided. The shield member 122 is not affected by noise, and the shield member 122 can be easily grounded via the support unit 140 of the optical writing head 110. In addition, since the drive circuit board 120 has a single unit structure with the optical writing head 110, the positional relationship between the drive circuit board 120 and the optical writing head 110 is fixedly maintained. Even when the partial substrate 112 is connected via the flexible cables 125 and 126, the electrical connection between the two can be maintained robustly.
[0054]
【The invention's effect】
(1) The positional relationship between the substrate surface of the drive circuit board and another functional unit is formed by separately forming the head part substrate on which the light emitting element of the writing head that emits image light is mounted and the drive circuit board. Can be inclined with respect to the optical axis of the image light at an angle in consideration of the above. As a result, the degree of freedom in design around the optical writing device is increased, each part constituting the solid scanning optical writing device can be efficiently arranged, and the image forming apparatus can be downsized.
[0055]
(2) By connecting the drive circuit board to the head part substrate on which the light emitting element is mounted via a flexible cable, the image of the substrate surface of the drive circuit board irradiated from the light emitting element mounted on the head part substrate Even when the optical circuit is tilted at an arbitrary angle with respect to the optical axis of the light, the electrical connection state between the drive circuit board and the head unit board can be maintained well. Further, when a failure occurs in one of the drive circuit board or the head part substrate, only the failed one can be replaced and the normal other can be used efficiently and continuously.
[0056]
(3) By attaching the drive circuit board together with the shield member to the support member of the optical writing head, the drive circuit board can be prevented from being affected by noise, and the shield is provided via the support member of the optical write head. The member can be easily grounded. Further, the positional relationship between the drive circuit board and the optical writing head can be fixedly maintained by making the drive circuit board and the optical writing head into a single unit structure, and the drive circuit board and the head unit board can be connected. Even when connected via a flexible cable, the electrical connection between the two can be maintained robustly.
[0057]
(4) The drive circuit board in the optical writing device arranged adjacent to the imaging device around the image carrier is made substantially parallel to the outer wall on the optical writing device side in the imaging device. As a result, the functional units including the optical writing device and the visualization device can be efficiently arranged, and the substrate area of the drive circuit substrate can be sufficiently secured.
[0058]
(5) Arranging the optical writing device so that the substrate surface of the drive circuit substrate is substantially vertical in a narrow space between a plurality of visualization devices each formed with the vertical direction as the longitudinal direction. Accordingly, the arrangement width of the optical writing device can be narrowed in the sub-scanning direction, which is the direction in which a plurality of visualization devices are arranged, and the image forming apparatus can be downsized in the sub-scanning direction.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a configuration of an image forming apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating a configuration of a main part of the image forming apparatus, and illustrates a configuration and an arrangement state of the optical writing device.
FIG. 3 is a perspective view illustrating a configuration of an optical writing device used in the image forming apparatus.
FIG. 4 is a side view showing a configuration of the optical writing device.
FIG. 5 is a diagram showing a configuration of an image forming apparatus using a conventional solid scanning optical writing device.
FIG. 6 is a diagram illustrating a configuration of an image forming apparatus using a conventional laser scan unit.
[Explanation of symbols]
1 (1a-1d) -optical writing device
2 (2a to 2d) -developing unit (visualization device)
3 (3a to 3d) -photosensitive drum (image carrier)
5 (5a-5d)-charger
100-Image forming apparatus
110-Write head
112-Head part substrate
113-LED (light emitting device)
120-Drive circuit board
122-Shield member
140-Support unit (support member)

Claims (3)

In an optical writing device that irradiates image light based on image data on the surface of an image carrier between a charger and a visualization device in an image forming apparatus that performs electrophotographic image formation,
A writing head including a head substrate on which a plurality of surface-emitting light-emitting elements are mounted in an array, a lens array that forms image light emitted from the light-emitting elements on the surface of an image carrier, and the light-emitting elements and a driving circuit substrate over which the driver circuit is mounted to be driven, the driving circuit board, independently formed from said write heads,
A support member that supports the drive circuit board so that a main surface thereof is positioned between the charger and the visualization device so as to be substantially parallel to an outer wall on the charger side of the visualization device; A support member that supports the head unit substrate and the lens array so that the optical axis of the image light passes through the rotation center of the image carrier,
The support member includes a first block and a second block that hold both ends of the write head, a connecting member that connects the first block and the second block, and holds the drive circuit board, And the connecting member is made of a material that is easier to deform than the first block, the second block, and the writing head. An image forming apparatus comprising: an image carrier; and a transfer device that transfers a visible image from the image carrier to a recording medium.
Furthermore, an optical writing device according to claim 1, and a visualizing unit for visualizing the electrostatic latent image formed on said image bearing member by irradiation of an image light from the optical writing device provided by adjacent image forming apparatus characterized by transferring the visualized image to the recording medium from the image carrier by the transfer device. An image forming apparatus in which a plurality of image carriers are juxtaposed in the moving direction of a recording medium together with the same number of optical writing devices and imaging devices, and the drive circuit board is disposed between the imaging devices. The image forming apparatus according to claim 2.

Images