JP2006053224A - Optical writing device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical writing device which prevents a plastic lens from deforming by the heat from the heating source and maintain the excellent image forming without complicating it and without incurring cost increases, and also to provide an image forming device. <P>SOLUTION: This optical writing device makes scanning by moving the light beams from the light source units 52, 53, 54, and 55 with an optical deflector 62, and focuses an image on the scanned surface of an image carrier by guiding the light from the optical deflector 62 through at least one or more plastic lenses 63, 64. And one or more ribs 502, 502' are disposed from the housing boss (fixing boss) Hb2 for securing the optical deflector to the rear surfaces of the areas where the plastic lenses 63, 64 are positioned. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical writing apparatus that irradiates a scanning surface of an image carrier with a light beam and writes a latent image, and includes the optical writing apparatus and develops a latent image formed on the image carrier. The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a plotter that develops with an agent and then sequentially transfers the image onto a transfer material and fixes it with a fixing means.

In recent years, there has been a demand for an improvement in printing speed when developing and printing a latent image formed on an image carrier by an optical writing device. Accordingly, an optical deflector that is a component of the optical writing device rotates at high speed. It is requested.
As the optical deflector rotates at a higher speed, the current value of the electric power supplied to the motor constituting the optical deflector increases, and therefore the amount of heat generated by the stator, which is a component of the motor, becomes extremely large.

As described above, since the amount of heat generated by the optical deflector is extremely large, there is a problem that the heat is transmitted to the plastic lens through the housing fixing the optical deflector and the lens itself is distorted by heat.
In addition, the way heat is transmitted to the plastic lens is usually transmitted concentrically around the heat source, resulting in a temperature deviation within the plastic lens, and the expansion coefficient varies locally within the plastic lens. Such as a large magnification shift and a difference in magnification deviation of a certain length may occur.

  In order to solve such a problem, a technique is known in which the pressure in the sealed chamber is controlled while presupposing that the optical deflector is sealed so that the heat is not reduced and the heat is not conducted. (For example, refer to Patent Document 1).

JP-A-10-221633

However, in the case of the above prior art, it is necessary to add a lid member and a pressure control device when sealing the optical deflector section, and there is a problem that the writing device becomes complicated and costs increase.
Furthermore, in order to suppress heat generation, a fan motor has been generally used, and forced cooling such as cooling the vicinity of the polygon motor and the writing device itself by a duct is performed so as not to transfer heat to the optical element. This also causes the problem that the writing device becomes complicated and the cost increases.

  The present invention has been made in view of such a background, and the optical writing device is made of plastic, in which the heat generated in the optical deflector is an optical element without complicating and without cost. By preventing the light from being transmitted unevenly to the lens, it is possible to prevent local distortion from occurring due to the effect of heat on the plastic lens itself and to maintain good image formation. An object is to provide an apparatus and an image forming apparatus.

  In order to achieve the above object, according to the first aspect of the present invention, the light beam from the light source unit is deflected and scanned by an optical deflector, and the light from the optical deflector is imaged through at least one plastic lens. In the optical writing apparatus that guides and forms an image on the surface to be scanned of the carrier, one or more ribs are provided from the housing boss for fixing the optical deflector to the back surface of the plastic lens arrangement portion. Features.

  The invention according to claim 2 is characterized in that the rib is made of a material having higher thermal conductivity than the housing material.

  According to a third aspect of the present invention, when there are a plurality of housing bosses for fixing the optical deflector, the plurality of housing bosses are connected to each other by connecting ribs.

  The invention described in claim 4 is characterized in that the housing boss, or the one or more ribs, or the connecting rib, and a bearing portion of the optical deflector are connected by a bypass rib.

  An image forming apparatus according to a fifth aspect of the invention is characterized by using the optical writing device according to at least one of the first to fourth aspects.

  According to the present invention, the apparatus is configured to prevent heat generated by the optical deflector from being unevenly transmitted to a plastic lens as an optical element without complicating the apparatus and without cost. Accordingly, it is possible to provide an optical writing device and an image forming apparatus that can prevent local distortion from being caused by heat in the plastic lens itself and maintain good image formation.

  That is, according to the first aspect of the present invention, since one or more ribs are formed from the housing boss to the back surface of the plastic lens arrangement portion, the apparatus is not complicated and the cost is not increased. In addition, it is possible to prevent heat generated by a heat source such as an optical deflector or a polygon motor from being transmitted to the lens non-uniformly, and to solve the problem that local distortion occurs due to a temperature distribution difference in the lens itself. And good image formation can be maintained.

  According to the second aspect of the present invention, in addition to the function and effect of the first aspect, the rib is made of a material having a higher thermal conductivity than the housing material, so that heat is easily transmitted to the rib, and the above-described effects are further improved. To do. In particular, it is possible to efficiently prevent heat from being unevenly transmitted to the lens and to increase the amount of heat transmitted to the rib. Therefore, the amount of heat transmitted to the housing base is slightly reduced, and the temperature rise of the lens itself can be further suppressed.

  According to invention of Claim 3, in addition to the effect of Claim 1, the temperature difference of housing bosses is reduced by directly connecting the housing bosses for fixing a plurality of deflectors with the connecting ribs, The amount of heat transferred from there to the ribs is also made uniform. Therefore, it is possible to effectively prevent heat generated by an optical deflector or the like from being transmitted nonuniformly to the lens without complicating the writing device and without further costing, and causing local distortion in the lens itself. The problem that occurs can be solved more efficiently.

  According to the fourth aspect of the present invention, in addition to the effect of the first aspect, the housing boss, the plurality of ribs, or the connecting rib, and the bearing portion of the optical deflector are bypass ribs. As a result, the coil, frictional heat, etc. are efficiently and evenly transferred to the housing boss through the bearing of the housing in the center of the motor, without complicating the device and without further cost, Heat generated by a heat source such as a motor can be more uniformly transmitted to the lens, and the problem that local distortion occurs in the lens itself can be solved more reliably.

  According to the fifth aspect of the present invention, the image forming apparatus can perform better image formation by mounting the optical writing apparatus according to the first to fourth aspects on the image forming apparatus.

  The optical writing apparatus of the present invention will be described below with reference to the accompanying drawings. The optical writing apparatus according to the present invention will be described as applied to a color copying machine as an example of an image forming apparatus. First, prior to description of the optical writing apparatus of the present invention, a schematic configuration of a color copying machine as an example of an image forming apparatus will be described.

  FIG. 1 is an explanatory diagram for explaining a schematic configuration of a color copying machine equipped with an optical writing apparatus according to the present invention. The color copying machine shown in FIG. 1 has a plurality of drum-shaped photoconductive photoreceptors (hereinafter referred to as photoreceptor drums) 1, 2, 3, 4 arranged side by side as an example of a plurality of image carriers. For example, the four photosensitive drums 1, 2, 3, 4 form an image corresponding to each color of black (Bk), cyan (C), magenta (M), and yellow (Y) sequentially from the right in the figure. (The order of the colors is not limited to this, and can be set arbitrarily).

  Around each of the four photosensitive drums 1, 2, 3, 4, charging units (charging roller, charging brush, charging charger, etc.) 6, 7, 8, 9, exposure portions of the light beams L 1, L 2, L 3, and L 4 from the optical writing device 5, developing portions (developing devices for the respective colors Bk, C, M, and Y) 10, 11, 12, and 13, and transfer A transfer conveyor device 22 having transfer means (transfer rollers, transfer brushes, etc.) 14, 15, 16, 17 disposed on the back side of the conveyor belt 22 a and a cleaning unit (cleaning blade, cleaning brush, etc.) 18, 19, 20, 21, etc. are arranged, and image formation of each color can be performed on each of the photosensitive drums 1, 2, 3, 4.

More specifically, in FIG. 1, when the Z direction in the drawing is a vertically upward direction and the X 1 and Y directions are horizontal directions, the parallel arrangement direction of the four photosensitive drums 1, 2, 3, 4 is relative to the horizontal plane. The transfer / conveying device 22 is substantially parallel to the juxtaposed direction of the four photosensitive drums 1, 2, 3, 4. In this way, it is arranged so as to be inclined with respect to the horizontal plane.
The transfer material (recording medium) is fed from the lower side in the inclined direction and is sequentially conveyed to the transfer portions of the four photosensitive drums 1, 2, 3, and 4 by the transfer conveyance belt 22a. A fixing device 26 is disposed on the downstream side in the conveyance direction of the transfer material and on the upper side in the inclination direction.
The optical writing device 5 is disposed obliquely above the image forming unit in which the four photosensitive drums 1, 2, 3, and 4 are arranged in parallel, and the housing 50 of the optical writing device 5 includes four photosensitive drums. Inclined frames 29 1, 30 of the color copying machine main body are arranged so as to be inclined with respect to a horizontal plane (X direction in the drawing) so as to be substantially parallel to the parallel arrangement direction of the body drums 1, 2, 3, 4. It is fixed to.

Here, as shown in FIG. 2, the optical writing device 5 includes four light source units 52, 53, 54, 55 and light beams L1, L2, L3 from the light source units 52, 53, 54, 55. An optical deflector 62 that deflects and scans L4 in two symmetrical directions, and a plurality of light beams L1 that are arranged symmetrically in the two directions around the optical deflector 62 and are deflected and scanned by the optical deflector 62. An optical system (image forming lenses 63, 64, 69, 70, 71, 72, optical path folding) for guiding L2, L3, and L4 onto the scanned surfaces of the corresponding photosensitive drums 1, 2, 3, and 4, respectively. Mirrors 65, 66, 67, 68, 73, 74, 75, 76, 77, 78, 79, 80, etc.), and these constituent members are housed in one housing 50. ing.
At least the imaging lenses 63 and 64 correspond to the plastic lenses described in the claims. You can think of other lenses as being made of plastic.

More specifically, as shown in FIG. 3, the housing 50 includes a base 50A on which the optical deflector 62 and the optical system are disposed, and a frame-like side wall 50B surrounding the base 50A. 50A is provided in a substantially central portion of the side wall 50B to partition the housing 50 up and down.
The four light source units 52, 53, 54, and 55 are arranged on the side wall 50 </ b> B of the housing 50 and are arranged side by side in substantially the same direction as the direction in which the photosensitive members are arranged in parallel. Optical members (imaging lenses 63, 64, 69, 70, 71, 72, optical path folding mirrors 65, 66, 67, 68, 73, 74, 75, 76, 77) arranged in the optical system and constituting the optical system , 78, 79, 80, etc.) are arranged separately on both surfaces (upper surface side and lower surface side) of the base 50A.
Covers 87 and 88 are provided at the upper and lower portions of the housing 50, and an opening through which the light beam passes is provided in the lower cover 87, and dustproof glasses 83, 84, 85, and 86 are provided in the openings. Is attached.

In this optical writing device 5, color-separated image data input from a document reading device (scanner) or an image data output device (personal computer, word processor, facsimile receiving unit, etc.) (not shown) is used as a light source driving signal. The light source (semiconductor laser (LD)) in each light source unit 52,53,54,55 is driven according to it, and a light beam is radiate | emitted.
The light beams emitted from the light source units 52, 53, 54, and 55 pass through cylindrical lenses 56, 57, 58, and 59 for surface tilt correction to the optical deflector 62 directly or via the mirrors 60 and 61, Deflection scanning is performed in two symmetrical directions by two-stage polygon mirrors 62a and 62b rotated at a constant speed by a polygon motor 62c.
In the configuration shown in FIGS. 1 to 3, the polygon mirror is divided into two upper and lower stages for the L2 and L3 light beams and the L1 and L4 light beams. It is good also as a structure which carries out a deflection scan by.

  The light beams deflected and scanned in two directions by the polygon mirrors 62a and 62b of the optical deflector 62 in two directions pass through imaging lenses 63 and 64 made up of, for example, upper and lower two-layer FΘ lenses. After being folded by the folding mirrors 65, 66, 67, and 68 and passing through the opening of the base 51, the second imaging lenses 69, 70, 71, and 72 made of, for example, a long toroidal lens are passed, 2 fold mirrors 73, 75, 77, 79, third fold mirrors 74, 76, 78, 80, dust-proof glasses 83, 84, 85, 86 through the photosensitive drums 1, 2, 3, 4 for each color. An electrostatic latent image is written on the scanning surface.

Next, as shown in FIG. 1, a transfer conveyance belt 22a stretched between a driving roller and a plurality of driven rollers is disposed below the four photosensitive drums 1, 2, 3, 4 arranged in parallel. It is conveyed in the direction indicated by the arrow in the figure by the drive roller.
In addition, a plurality of paper feeding units 23 and 24 that store transfer materials such as recording paper are installed at the lower part of the main body of the image forming apparatus, and the transfer materials stored in the paper feeding units 23 and 24 feed paper. The paper is fed to the transfer / conveyance belt 22a via the rollers, the conveyance rollers, and the registration rollers 25, and is carried and conveyed by the transfer / conveyance belt 22a.

  The latent images formed on the photosensitive drums 1, 2, 3, and 4 by the optical writing device 5 are made of toners of Bk, C, M, and Y colors of the developing units 10, 11, 12, and 13, respectively. The developed and visualized toner images of Bk, C, M, and Y colors are transferred onto the transfer conveyance belt 22 a by the transfer units 14, 15, 16, and 17 of the transfer conveyance device 22. The images are sequentially superimposed and transferred onto the transferred transfer material. The transfer material onto which the four color images have been transferred is conveyed to the fixing device 26, where the image is fixed by the fixing device 26, and then discharged onto the paper discharge tray 28 by the paper discharge roller 27.

FIG. 4 is a bottom view explanatory view showing the positional relationship between the imaging lenses 63 and 64 and the polygon mirror 62. The polygon motor 500 is a heat source (the bearing portion at the center of rotation is simply the center of the heat source). ) Shows the state of heat transfer to the imaging lenses (FΘ lenses) 63 and 64 via the housing base (see FIG. 6) Hb.
As shown in FIG. 4, when the polygon motor 500 is started, a temperature distribution is generated on a concentric circle centered on the rotation center of the polygon motor 500.
Although the temperature distribution shown in FIG. 4 is an example, it has been experimentally confirmed that one-dot chain lines in the order closer to the center show temperature contour lines of 55 ° C., 52 ° C., 49 ° C., 46 ° C., and 43 ° C.
In this case, the temperature distribution of the imaging lenses (FΘ lenses) 63 and 64 fixed to the housing base Hb has a plurality of temperature regions as shown by oblique lines following the temperature contour lines.

  Actually, since there is heat transfer in the imaging lenses (FΘ lenses) 63 and 64, the temperature region becomes ambiguous, or the temperature deviation is relaxed, but there is a temperature distribution. The expansion coefficients in the lenses 63 and 64 are different, and as a result, there arises a problem that a local magnification shift and a deviation of a fixed length magnification are different, which causes image deterioration.

  The first embodiment of the present invention (corresponding to claim 1) specifically shows an optical writing device that has been technically created to improve the above-mentioned problems. FIG. 5 is an explanatory view for explaining the installation relationship of the rib 502 and the like, which are technically the core of the present embodiment, with respect to the housing base Hb.

The hatched portion shown in FIG. 5 represents the cross-sectional shape of the housing base Hb. On the housing base Hb, a fixing boss portion for fixing the polygon mirror 62 connected to the rotation shaft of the polygon motor 500 (see FIG. 6; the same applies below) (housing boss for fixing the optical deflector: the same applies below) Hb2 Are arranged at four positions around the polygon mirror 62.
The four fixing bosses Hb2 project downward from the rear surface of the housing base Hb in the figure, and screws 501 are provided via a flat support plate (polygon motor base) for fixing the motor bearing 500a of the polygon motor 500. It is screwed. With this screw 501, the motor bearing 500a is fixed and the polygon mirror 62 is rotatably fixed.
Further, on the back side of the housing base Hb, a motor bearing support portion (corresponding to the bearing portion of the optical deflector described in the claims: the same applies below) Hb3 is configured to support the motor bearing 500a of the polygon motor 500. Thus, blurring or the like is prevented when the polygon motor 500 is started.

In particular, the four fixing bosses Hb2 are easy to conduct heat from the polygon motor 500, and this heat is transmitted to the imaging lenses 63 and 64 so as to make the temperature distribution of the imaging lenses 63 and 64 constant. A plurality of ribs 502, 502 ', 503, and 503' are provided from the four fixing bosses Hb2 to positions (arrangement portions) corresponding to the installation positions of the imaging lenses 63 and 64 on the back surface of the housing base Hb. It is extended in contact state.
That is, the plurality of ribs 502 and the like from each fixing boss Hb2 to the arrangement portion of the imaging lenses (FΘ lenses) 63 and 64 are in contact with the back surface of the housing base Hb, and the housing base Hb is connected to the imaging lenses 63 and 64. It extends to be sandwiched between.

FIG. 6 is an explanatory diagram for explaining the arrangement of a plurality of ribs 502 and the like when the housing base Hb of the present embodiment is viewed from the back side.
As shown in FIG. 6, the heat generated by the polygon motor 500 indicated by the dotted line is transmitted to the housing base Hb via the motor fixing portion (that is, including the motor bearing support portion Hb3). Therefore, the ribs 502, 502 ′, 503, 503 ′, 504, 504 ′, 505, and 505 ′ are placed under the imaging lenses (FΘ lenses) 63 and 64 from the fixing bosses Hb2 on the rear surface of the housing base Hb. It extends so-called radially to the side.
The temperature of the imaging motor (FΘ lens) 63, 64 is low through the ribs 502, 502 ′, 503, 503 ′, 504, 504 ′, 505, 505 ′ from the fixing boss Hb2 to the heat of the polygon motor 500. It is transmitted to a part, for example, a region of 43 ° C. or lower (see FIG. 4).

That is, the amount of heat transmitted by the ribs 503, 503 ′, etc. is made uniform by making the length of the ribs extending from one fixing boss Hb2 approximately equal to the length of the ribs 503, 503 ′, etc. Reduce non-uniformity.
The ribs 502, 502 ′, 503, 503 ′, 504, 504 ′, 505, 505 ′ raise the temperature of the low temperature portion of the imaging lens (FΘ lens) 63, 64, thereby forming the imaging lens 63. , 64 is made uniform.
As a result, the expansion coefficient inside the plastic imaging lenses 63 and 64 is kept constant to prevent distortion and the like, and the phenomenon of local magnification deviation and difference in magnification of a certain length is eliminated. can do. As a result, it is possible to prevent image quality from deteriorating and maintain high-quality image formation.

Next, an optical writing apparatus according to a second embodiment (corresponding to claim 2) of the present invention will be described. Although not shown in detail, the optical writing apparatus of the present embodiment is basically the same as that of the first embodiment, and the detailed description of the same parts is omitted.
The housing base Hb shown in FIG. 5 is often molded from plastic for the purpose of cost reduction and weight reduction. Plastics generally have a lower thermal conductivity than metal materials and are difficult to transfer heat.
Therefore, in the present embodiment, in order to sufficiently exhibit the effects described in the first embodiment, the amount of heat equivalent to the heat transmitted from the entire housing base Hb is applied to each rib 502, 502 ′, 503, 503. It is desirable to transmit to the low temperature side of the imaging lenses 63 and 64 by ', 504, 504', 505 and 505 '.
Therefore, in the present embodiment, the ribs 502, 502 ′, 503, 503′504, 504′505, and 505 ′ are formed of a metal system having higher thermal conductivity than the housing base Hb, for example, aluminum or copper.

In this case, compared with the case of the first embodiment, the effect of making the temperature distribution of the imaging lenses 63 and 64 more uniform can be improved.
Further, since the amount of heat transmitted to the ribs 502, 502 ′, 503, 503′504, 504′505, and 505 ′ increases, the amount of heat transmitted to the housing base Hb is slightly reduced, and the temperature rise of the imaging lenses 63 and 64 itself is suppressed to a low level. be able to.
Generally, mold thermal conductivity (typically about 5 to 50 W / m · k at normal temperature) <heat conductivity of aluminum or copper heat sink (aluminum: generally about 240 W / m at normal temperature)・ K and copper: Generally, about 400 W / m · k at normal temperature), it is preferable to use aluminum or a copper material for each rib 502 or the like, but other metals or the like may be used. Of course.

Next, an optical writing device according to a third embodiment (corresponding to claim 3) of the present invention will be described. Although not shown in detail, the optical writing apparatus of the present embodiment is basically the same as that of the first embodiment, and the detailed description of the same parts is omitted.
FIG. 7 is an explanatory view for explaining the arrangement of the plurality of ribs 502 and the like and the connecting ribs 701 when the housing base Hb of the present embodiment is viewed from the back side.
As shown in FIG. 7, the connecting rib 701 connects the four fixing bosses Hb2 in a so-called square ring shape as indicated by oblique lines, and each rib 502, 502 ′, 503, 503 ′ 504, 504. It is also connected to '505, 505'.
Note that the connecting rib 701 may be an integral rectangular annular member, or may be used by connecting individual members one by one.

Each of the four fixing bosses Hb2 has a polygon motor substrate attached thereto, but the temperatures of the four portions of the polygon motor substrate (that is, the portions of the fixing bosses Hb2) do not necessarily match. I don't mean.
For example, when the motor driver 500b in the figure, which generates a large amount of heat when the motor rotates, is arranged below the polygon motor board, the two other fixing bosses Hb2 near the motor driver 500b are the other two, that is, the upper side in the figure. The temperature tends to be higher than the two fixing bosses Hb2 farthest from the motor driver 500b.

In the present embodiment, the four fixing bosses Hb2 and the ribs 502, 502 ′, 503, 503′504, 504′505, and 505 ′ are connected by the connecting ribs 701. Even if the driver 500b generates heat, temperature nonuniformity of the ribs 502, 502 ′, 503, 503′504, 504′505, and 505 ′ does not occur.
For this reason, the expansion rate inside the plastic imaging lenses 63 and 64 is kept constant to prevent distortion and the like, and the phenomenon that the local magnification deviation and the deviation of the constant magnification are different. Can be resolved. As a result, it is possible to prevent image quality from deteriorating and maintain high-quality image formation.

Next, an optical writing device according to a fourth embodiment (corresponding to claim 4) of the present invention will be described. Although not shown in detail, the optical writing apparatus of the present embodiment is basically the same as that of the first embodiment, and the detailed description of the same parts is omitted.
FIG. 8 is an explanatory diagram for explaining the arrangement of the plurality of ribs 502, the connecting ribs 701, and the bypass ribs 801 when the housing base Hb of the present embodiment is viewed from the back side.
As shown in FIG. 8, in the present embodiment, four fixing bosses Hb2 are provided to the four fixing bosses Hb2 from the motor bearing support (bearing part of the optical deflector) Hb3. A bypass rib 801 is connected to the connecting rib 701 to be connected.
In the case of this example, each bypass rib 801 is directed from the motor bearing support portion (bearing portion of the optical deflector) Hb3 to the four fixing boss portions Hb2, and accordingly, each of the four fixing bosses radiates. You may think that it is connected with part Hb2.

The motor bearing support (rotation center) Hb3 is provided with a coil having the highest calorific value, and the motor bearing support Hb3 is subjected to frictional heat generated by rotation of the polygon mirror rotating shaft (injecting lubricant such as oil into the interior). It may be quite hot).
In the present embodiment, since the heat generated in the high temperature portion is also uniformly transferred to the fixing boss Hb2 by the bypass ribs 801, the effects obtained in the first to third embodiments are further improved. To do.

  The optical writing apparatus according to each of the embodiments described above is used for the color copying machine as the image forming apparatus described above. However, the connecting ribs such as the respective ribs 502 forming the core of the technical idea of the present invention. The rib 701 and the bypass rib 801 may be formed by forging using an iron-based material, and the screw 501 that is screwed into the fixing boss Hb2 may be formed of, for example, a zinc material.

  The optical writing apparatus of the present invention can be used as an image forming apparatus for a printer, a facsimile, a plotter, etc. in addition to a copying machine.

It is explanatory drawing explaining an example of the image forming apparatus which uses the optical writing device of this invention. It is a top view explanatory drawing explaining an example of the technique used as the premise of the optical writing apparatus of this invention. It is side view explanatory drawing explaining an example of the technique used as the premise of the optical writing apparatus of this invention. It is principal part explanatory drawing explaining an example of the temperature distribution characteristic of the technique used as the premise of the optical writing apparatus of this invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view main part explanatory diagram for explaining a configuration of an optical writing device according to a first embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a back view main part explanatory view for explaining a configuration of an optical writing device according to a first embodiment of the present invention. It is a back view principal part explanatory drawing explaining the structure of the optical writing apparatus which concerns on the 3rd Embodiment of this invention. It is a back view principal part explanatory drawing explaining the structure of the optical writing apparatus which concerns on the 4th Embodiment of this invention.

Explanation of symbols

1, 2, 3, 4 Photosensitive drum 5 Optical writing device 6, 7, 8, 9 Charging unit L1, L2, L3, L4 Light beam 10, 11, 12, 13 Developing unit 14, 15, 16, 17 Transfer Means 18, 19, 20, 21 Cleaning unit 22 Transfer conveyance device 22a Transfer conveyance device 23, 24 Paper feed unit 25 Registration roller 26 Fixing device 27 Paper discharge roller 28 Paper discharge tray 29, 30 Frame 50 Housing 50A Base 50B Side wall 52, 53, 54, 55 Light source unit 56, 57, 58, 59 Cylindrical lens 60, 61 Mirror 62 Optical deflector 62a, 62b Polygon mirror 63, 64, 69, 70, 71, 72 Imaging lens (plastic lens)
65, 66, 67, 68, 73, 74, 75, 76, 77, 78, 79, 80 Optical path folding mirror 83, 84, 85, 86 Dust-proof glass 87, 88 Cover Hb Housing base Hb2 Fixing boss (housing boss)
Hb3 motor bearing support (bearing part of optical deflector)
500 Polygon motor 500a Motor bearing 500b Motor driver 501 Screw 502, 502 ′, 503, 503 ′, 504, 504 ′, 505, 505 ′ Rib 701 Connecting rib 801 Bypass rib

Claims (5)

An optical writing apparatus that deflects and scans a light beam from a light source unit by an optical deflector and guides light from the optical deflector onto a scanned surface of an image carrier through at least one plastic lens. In
One or more ribs are arranged from the housing boss for fixing the optical deflector to the back surface of the plastic lens arrangement portion.   The optical writing device according to claim 1, wherein the rib is made of a material having a higher thermal conductivity than a housing material.   3. The optical writing device according to claim 1, wherein when there are a plurality of housing bosses for fixing the optical deflector, the housing bosses are connected to each other by a connecting rib.   4. The apparatus according to claim 1, wherein the housing boss, the one or a plurality of ribs, or the connecting rib and the bearing portion of the optical deflector are connected by a bypass rib. The optical writing device described. An image forming apparatus using the optical writing device according to claim 1.

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