JP4890954B2 - Optical writing apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to an optical writing apparatus and an image forming apparatus, and more particularly to an image forming apparatus that includes a deflecting device that deflects light from a light source and forms an image by electrophotography.

  In recent years, image forming apparatuses such as laser printers and digital copying machines are required to have high-quality images, high-speed image formation, space saving, energy saving, and low cost. Therefore, the optical system used in the optical writing device used in the image forming apparatus is also required to have high performance and low cost.

  In response to such a demand for higher image formation speed, the rotation speed of a deflecting device such as a polygon mirror used in the optical writing device is also high-speed rotation such as 30000 rpm or 40000 rpm. For this reason, in particular, a large amount of heat is generated from the rotary bearing of the deflecting device and the control IC, and various measures have been taken to deal with image quality degradation due to deformation of the casing and thermal expansion of the lens caused by the generated heat. Yes.

In order to dissipate the heat of the conventional deflection device effectively, the following techniques have been proposed. Japanese Patent Application Laid-Open No. H10-228667 describes a motor bearing for driving a polygon mirror provided with a heat radiating means made of a heat conductive material and fins to suppress excessive heat generation. Patent Document 1 describes a polygon scanner having a configuration in which a heat radiating fin is formed at one end of a heat radiating member made of a heat conducting member and the other end is fixed in contact with the polygon scanner, and an optical scanning device equipped with the polygon scanner. . Furthermore, Patent Document 1 describes a configuration in which a polygon scanner is attached to a groove-like flow path for introducing outside air formed on the outer surface of a housing.
JP 2001-242408 A

  However, in the above-described conventional technology, the target deflection device is such that a polygon scanner composed of a polygon mirror and a substrate is surrounded by a casing made of an upper case and a lower case (flange), and a heat radiating member is enclosed in this casing. Is fixed. For this reason, it cannot be used immediately for a general-purpose deflecting device including only a polygon mirror and a substrate.

  Accordingly, an object of the present invention is to enable effective cooling of an optical writing device having a general-purpose deflecting device including a polygon mirror and a substrate with an easy structure.

  The invention of claim 1 is an optical writing device that is attached to one side of a housing and includes a deflecting device that deflects a light beam from a light source and forms a latent image by irradiating the image carrier with the light beam. The opening is opened, and a peripheral portion of the opening is provided with a housing provided with a mounting portion for mounting the deflecting device and elasticity, and is attached to the mounting surface of the deflecting device to the housing. A heat transfer sheet, a first heat radiating member attached to the attachment surface portion via the heat transfer sheet, and attached to the first heat radiating means, penetrating through an opening of the housing, and the deflection device An optical writing device comprising: a second heat radiating member protruding to the opposite side to the side on which the is attached.

  According to a second aspect of the present invention, in the optical writing device according to the first aspect, the second heat radiating member is formed with a heat radiating protrusion.

  According to a third aspect of the present invention, in the optical writing device according to the second aspect, the heat dissipating member is a sheet metal member, and the projecting portion is a comb-like member formed by cutting out the sheet metal member. It is formed.

A fourth aspect of the present invention, an optical writing device according to claim 3 Symbol placement, the protruding portion is characterized in that it is configured to conform to the three faces erected from the mounting substrate portion.

  According to a fifth aspect of the present invention, in the optical writing device according to any one of the first to fourth aspects, a heat transfer sheet is disposed between the first heat radiating member and the second heat radiating member. To do.

The invention of claim 6 is an optical writing device according to any one of claims 1 to 5, 1 of the heat radiation member is attached from one side of the front Kikatamitai to the housing, the second heat radiating member characterized in that attached to the other side or al the housing of the casing.

A seventh aspect of the present invention is an image forming apparatus comprising the optical writing device according to any one of the first to fifth aspects .

  According to the optical writing device of the present invention, the first heat dissipating member attached to the attaching surface portion via the heat transfer sheet and the first heat dissipating means, and penetrates the opening of the housing. Since the second heat radiating member projecting to the side opposite to the side on which the deflecting device is mounted is provided, the heat generated by the deflecting device is reliably transmitted from the first heat radiating member to the second heat radiating member. To be cooled. For this reason, there is an effect that the optical writing device provided with the deflecting device having a general structure composed of the polygon mirror and the substrate can be effectively cooled with an easy structure.

  Embodiments as the best mode for carrying out the present invention will be described below with reference to the drawings.

  Embodiments of an image forming apparatus using an optical writing device according to the present invention will be described below. FIG. 1 is a cross-sectional view illustrating a configuration of an image forming apparatus according to an embodiment. The image forming apparatus 100 according to this example is a full-color printer using an electrophotographic method. In this example, the image forming apparatus 100 includes four image forming units 110Y, 110C, 110M, and 110K corresponding to yellow (Y), magenta (M), cyan (C), and black (K). Yes. The image forming units 110Y, 110C, 110M, and 110K are respectively provided with photosensitive drums 101. The photosensitive drums 101 are arranged in the order of rotation in the charging direction and the exposure unit (optical writing device) 106, respectively. , A developing unit 102, transfer units 112 and 113, and a cleaning unit 107 are provided.

  Here, each charging means 108 is a conductive roller formed in a roller shape, and a charging bias voltage is supplied to the roller from a power supply device to uniformly charge the surface of the photosensitive drum 102.

  The optical writing device 106 relates to an embodiment of the optical writing device according to the present invention, and includes therein a semiconductor laser 1, a coupling lens 2, an aperture 3, a cylindrical lens 4, a polygon mirror 5, a scanning lens 6, and the like. (Not shown). The optical writing device 106 irradiates the surface of the photosensitive drum with laser light to be turned on / off based on the image data, thereby forming an electrostatic latent image on the photosensitive drum.

  Each developing unit 102 visualizes the electrostatic latent image formed on the photosensitive drum as a toner image with a developer, and the transfer unit 112 transfers the toner image on the photosensitive member from the photosensitive member. Further, each cleaning unit 107 removes the developer remaining on the photosensitive drum 102 after the transfer.

  The image forming apparatus 100 according to the present example transfers the toner image on each photosensitive drum 102 to the intermediate transfer member 111 and then transfers the toner image onto a transfer material such as printing paper.

  The transfer material 103a such as printing paper is separated one by one by the roller 103b of the paper supply means 103, conveyed to the registration roller 103C, and further conveyed to the transfer means 113 described above.

  Next, the optical writing device will be described. FIG. 2 is a plan view showing an embodiment of the optical writing device used in the image forming apparatus shown in FIG. In this example, laser light emitted from a semiconductor laser 1 that oscillates laser light passes through a coupling lens 2, is shaped by an aperture 3, and enters a cylindrical lens 4 that is a line image imaging optical system. This lens has power in the sub-scanning direction and is condensed near the reflection surface of the polygon mirror 5.

The light beam reflected by the light deflecting device is deflected at a constant angular velocity as the polygon mirror rotates at a constant speed, passes through the scanning lens 6 and reaches the photosensitive member 7. A mirror is appropriately disposed in the optical path between them. Prior to optical scanning on the photosensitive member, the light beam is reflected by the mirror 8 and a synchronization detection device 10 obtains a synchronization signal.
The synchronization detection device 10 includes a lens 11, a light receiving element 12, and a synchronization detection board (signal generation circuit board) 13.

  FIG. 3 is a cross-sectional view showing an optical path of the optical deflecting device. In this example, two semiconductor lasers 1, a coupling lens 2, an aperture 3, a cylindrical lens 4, and two polygon mirrors 5 are arranged. In this example, the scanning plane after the polygon mirror 5 is configured in two upper and lower stages like the introduction part before the polygon mirror configured in two upper and lower stages.

Next, the structure of the optical writing device 106 according to this example will be described. FIG. 4 is a perspective view showing the optical writing device according to the first embodiment.
In this example, the optical writing device 106 attaches the optical deflection device 20 from above the housing 60 via the heat transfer sheet 30 and the first heat radiating member 40, and further attaches the second heat radiating member 50 from below. It is comprised by.

  In this example, the optical deflection apparatus 20 is configured by arranging parts such as the semiconductor laser 1 in addition to the polygon mirror 5 on the substrate 21 and is attached to the housing 60 with a machine screw.

  In this example, the housing 60 is formed with an engaging portion 63 for fitting and positioning the light deflecting device 20, and the engaging portion 63 has an opening 62 opened in the substrate 64 of the housing 60. Further, a deflection device mounting portion 61 that is disposed around the opening 62 and to which the light deflection device 20 is fixed with a small screw or the like, and a rib portion 65 that supports the 50 are formed.

  In this example, the first heat radiating member 40 is mounted on the rib portion 65 of the housing 60 before the light deflecting device is attached, and the heat transfer sheet 30 is placed thereon and fixed with a small screw. Thereby, the deformation of the first heat radiating member 40 is prevented.

  In this example, the heat transfer sheet 30 is a thin sheet having good thermal conductivity and elasticity such as rubber, and has a self-adhesive property. As such a heat transfer sheet, a commercially available sheet can be used.

  The first heat radiating member 40 is made of a metal having good thermal conductivity, for example, an aluminum plate, and the first heat radiating member 40 is formed with a mounting portion 41 of the second heat radiating member 50 protruding. . A screw hole is formed in the mounting portion 41, and the second heat radiating member 50 is screwed.

  Next, the second heat radiating member 50 will be described. FIG. 5 is a perspective view showing the configuration of the second heat radiating member. The second heat radiating member 50 according to this example is formed by cutting and molding an aluminum sheet metal, and is formed by radiating portions 52, 53, 54 standing on three sides of a quadrilateral bottom plate 51. In this example, the heat radiating portions 52, 53, 54 have a shape in which a large number of comb-like heat radiating protrusions 55 are erected. Such a configuration is formed by cutting out a sheet metal member that is erected from the three peripheral edges of the bottom plate 51. In the figure, reference numeral 56 denotes a screw hole for attachment to the first heat radiating member 40.

  In this example, since the heat radiating portions 52, 53, and 54 are formed in three directions, the airflow can pass through the heat radiating portion satisfactorily, and the heat radiating state can be improved. Therefore, in this example, the airflow hits the heat dissipation protrusion satisfactorily, and the heat dissipation efficiency is improved.

  In this example, the heat radiating protrusions 55 of the heat radiating portions 52, 53, and 54 of the second heat radiating member 50 can be formed so that adjacent heat radiating protrusions are not flush with each other. FIG. 6 is a plan view showing a second heat radiating member according to another embodiment. In this example, the heat radiating protrusions 55 of the heat radiating portions 52 and 54 are used as the inner heat radiating protrusion 55a and the outer heat radiating protrusion 55b so that adjacent heat radiating protrusions are not arranged on the same plane.

  In addition, if the flow of air is formed in the space where the second heat radiating member 50 is disposed, the cooling efficiency is further improved, and the shape of the heat radiating protrusion of the second heat radiating member 50 is a fin shape having a larger surface area. Further, the cooling efficiency is improved.

  Further, in this example, since the vertical positioning of the light deflecting device 20 is determined by the deflecting device mounting portion 61 of the housing 60, the dimensional error of the rib portion 65 of the housing 60 and the first heat radiating member 40 is reduced. The heat transfer sheet 30 can be absorbed within the elastic region.

  Furthermore, in this example, a plate material is used as the first heat radiating member 40 so that the cost does not increase. Moreover, the 2nd heat radiating member 50 protrudes below the housing | casing, and can secure a big heat radiating area, and it attaches the 2nd heat radiating member 50 separately from the bottom to the housing | casing 60 of the optical deflection apparatus 20. The handling property when assembling can be improved.

  Next, an optical writing device according to another embodiment of the present invention will be described. FIG. 7 is a perspective view showing an optical writing device according to another embodiment. In this example, the first heat radiating member 70 is a thick member, and the contact state with the second heat radiating member 50 is improved. The structure of the other members is the same as that of the first embodiment, and the same reference numerals are given to the same members in the figure.

  According to this example, the screw for mounting the second heat radiating member 50 is embedded in the screw hole formed in the first heat radiating member 70, and the heat of the first heat radiating member 70 is transferred to the second heat radiating member. The member 50 can be made to conduct well. For this reason, the heat dissipation effect is better than that of the first embodiment.

  In each of the above embodiments, the second heat radiating member is directly attached to the first heat radiating member. However, a heat transfer sheet can be sandwiched between the first heat radiating member and the second heat radiating member. . If it does in this way, thermal conductivity between the 1st heat dissipation member and the 2nd heat dissipation member can be made good.

1 is a cross-sectional view illustrating a configuration of an image forming apparatus according to an embodiment. FIG. 2 is a plan view showing an embodiment of an optical writing device used in the image forming apparatus shown in FIG. 1. It is sectional drawing which shows the optical path of an optical deflection apparatus. 1 is a perspective view showing an optical writing device according to a first embodiment. It is a perspective view which shows the structure of a 2nd heat radiating member. It is a top view which shows the 2nd heat radiating member which concerns on another Example. It is a perspective view which shows the optical writing device based on another Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Semiconductor laser 2 ... Coupling lens 3 ... Aperture 4 ... Cylindrical lens 5 ... Polygon mirror 6 ... Scanning lens 7 ... Photoconductor 8 ... Mirror 10 ... -Period detection device 11 ... Lens 12 ... Light receiving element 13 ... Period detection board (signal generation circuit board)
DESCRIPTION OF SYMBOLS 20 ... Light deflection apparatus 21 ... Board | substrate 30 ... Heat-transfer sheet 40 ... 1st thermal radiation member 41 ... Attachment part 50 ... 2nd thermal radiation member 51 ... Bottom plate 52, 53, 54 ... Radiating portion 55 ... Radiating projection 55a ... Radiating projection (inside)
55b ... Radiating protrusion (outside)
56 ... Screw hole 60 ... Housing 61 ... Deflector attachment part 62 ... Opening part 63 ... Engagement part 64 ... Substrate 65 ... Rib part 70 ... First Radiating member 100 ... image forming apparatus 101 ... image forming apparatuses 110Y, 110C, 110M, 110K ... image forming unit 101 ... photosensitive drum 102 ... developing means 103 ... feeding means 103a, transfer material 103b, roller 103C, registration roller 106, exposure means (optical writing device)
107: Cleaning means 108 ... Charging means 111 ... Intermediate transfer bodies 112, 113 ... Transfer means

Claims (7)

An optical writing device that is attached to one side of a housing and includes a deflecting device that deflects a light beam from a light source and forms a latent image by irradiating the image carrier with the light beam,
An opening is established, and a housing provided with a mounting portion for mounting the deflection device on the periphery of the opening;
A heat transfer sheet that comprises elasticity and is affixed to a mounting surface of the deflecting device to the housing;
A first heat radiating member attached to the attachment surface portion via the heat transfer sheet;
A second heat dissipating member attached to the first heat dissipating means, penetrating through the opening of the housing and projecting to the side opposite to the side on which the deflecting device is attached;
An optical writing device comprising:   2. The optical writing device according to claim 1, wherein the second heat radiating member is formed with a heat radiating protrusion.   3. The optical writing device according to claim 2, wherein the heat radiating member is formed of a sheet metal member, and the protrusion is formed as a comb-like member formed by cutting out the sheet metal member. The projection optical writing device according to claim 3 Symbol mounting, characterized in that it is configured to conform to the three faces erected from the mounting substrate portion.
  The optical writing device according to claim 1, wherein a heat transfer sheet is disposed between the first heat radiating member and the second heat radiating member. Mounting the first heat radiation member from one side of the front Kikatamitai to the housing, the second heat radiating member 1 through claim, characterized in that attached to the other side or we said housing of said casing 6. The optical writing device according to any one of 5 above.
An image forming apparatus comprising the optical writing device according to any one of claims 1 to 5.