JP2005208404A - Scanning optical apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive scanning optical apparatus which is excellent in printing accuracy and in workability for assembly. <P>SOLUTION: The scanning optical apparatus has: a light source device; a first imaging optical system which condenses a light beam emitted from the light source; a rotating polygon mirror which reflects and deflects the light beam passing through the first imaging optical system on a deflection and reflection face; a second imaging optical system which optically scans a photoreceptor with the light beam deflected with the polygon mirror and focuses as a spot on the photoreceptor; a horizontal synchronization signal detection means for detecting a signal of a writing-in position of a scanning line; an optical system for horizontal synchronization signal detection for guiding a portion of the light beam deflected with the rotating polygon mirror to the horizontal synchronization signal detection means; a slit which regulates the light beam made incident on the horizontal synchronization signal detection means; and a lid member which closes an optical box. The scanning optical apparatus is characterized by that the slit and the lid member are integrally formed as a unit. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a scanning optical device used in an image forming apparatus such as a laser printer or a laser facsimile.

  A scanning optical device used in an image forming apparatus such as a laser beam printer reflects a light beam such as a laser beam by a rotating polygon mirror that rotates at high speed, deflects and scans the light beam, and the obtained scanning light is sensitized on a rotating drum. An electrostatic latent image is formed by forming an image on the body. Next, the electrostatic latent image on the photosensitive member is visualized as a toner image by a developing device, transferred to a recording medium such as recording paper, sent to a fixing device, and the toner on the recording medium is heated and fixed to perform printing. Done.

  Conventionally, in order to guarantee the printing position accuracy in the scanning direction, the writing position of the scanning line has been adjusted.

  For example, Patent Document 1 discloses a conventional scanning optical device. That is, the horizontal sync detector, the slit for restricting the light beam incident on the horizontal sync detector, and the horizontal sync detector unit consisting of a holding member for holding them are moved in an arc shape to adjust the writing position. .

JP 2002-328321 A

  However, according to the above-described conventional scanning optical device, the workability when the writing position is readjusted with the scanning optical device attached to the image forming apparatus main body is poor, and the image is deteriorated due to the intrusion of dust during the work. There is a problem that occurs.

  In the configuration of an image forming apparatus such as a laser beam printer, an optical platform serving as a holding member of a scanning optical device is mounted on a main body frame serving as a housing for holding a developing device, a fixing device, a paper feeding device, a paper discharging device, a cartridge, In general, the adjusted scanning optical apparatus is positioned and fixed on the optical bench.

  Here, regarding the printing position accuracy in the scanning direction, the scanning optical writing position in the scanning optical device alone is adjusted by the method described in Patent Document 1 exemplified in the above-described prior art. In some cases, it may be necessary to readjust the scanning line writing position due to the error of the mounting position of the scanning optical device.

  Further, in order to reduce noise due to dust intrusion into the scanning optical device and rotation of the rotary polygon mirror, the scanning optical device is hermetically sealed by fixing a sheet metal or resin cover to the optical box with a screw or the like. It is common. For this reason, when the read-out position is readjusted as described above, the cover of the scanning optical device must be completely removed and the position of the horizontal synchronization detection unit must be adjusted, resulting in poor workability. . In addition, since the cover is removed during readjustment, dust in the air at the work site invades and adheres to the optical elements such as lenses and mirrors, or touches the optical elements during work and causes the optical elements to become dirty and scratched. As a result, there is a problem that image deterioration such as density unevenness may occur.

  In order to solve the above problem, for example, there is a means for adjusting the writing by moving the scanning optical device in the scanning direction with respect to the optical bench by providing a movement adjusting mechanism for the scanning optical device in the image forming apparatus. Since the components are necessary for the movement adjustment mechanism of the optical device, the configuration becomes complicated, and another problem arises in that the manufacturing cost of the entire device increases due to an increase in the number of components.

  An object of the present invention is to provide an inexpensive scanning optical device that solves the above problems, has high printing accuracy, and is excellent in assembling workability.

  In order to achieve the above object, a scanning optical device according to the present invention includes a light source device, a first imaging optical system for condensing a light beam emitted from the light source device, and the first imaging optical system. A rotary polygon mirror that reflects and deflects the light beam that has passed through the deflecting reflecting surface, and a second connection that optically scans the photosensitive member with the light beam deflected by the rotary polygon mirror and forms an image as a spot on the photosensitive member. An image optical system, a horizontal synchronization signal detecting means for detecting a scanning line writing position signal, and a horizontal synchronizing signal for guiding a part of the light beam deflected by the rotary polygon mirror to the horizontal synchronization signal detecting means In a scanning optical apparatus having a detection optical system, a slit for restricting a light beam incident on the horizontal synchronization signal detection means, and a lid member for closing the optical box, the slit is formed integrally with the lid member. That And butterflies.

  The lid member may be slidable in a direction perpendicular to the optical axis of the light beam incident on the front horizontal synchronization signal detecting means.

  Furthermore, it is further preferable that the lid member has a rotation reference portion, and the lid member is rotatable around the rotation reference portion.

  According to the present invention, the read-out position of the scanning line can be easily readjusted, the printing accuracy is high, the image density unevenness due to the contamination of the optical parts is not easily generated, and the workability at the time of adjustment is excellent. The scanning optical device can be provided at low cost.

  Further, by applying the scanning optical device according to the present invention to an image forming apparatus, an inexpensive image forming apparatus with high printing accuracy and excellent assembly workability can be provided at a low cost.

<Embodiment 1>
1 and 2 illustrate a first embodiment of a scanning optical apparatus according to the present invention.

  FIG. 1 is a perspective view of a scanning optical device according to the present embodiment. For the sake of explanation, the lid member 20 is shown in a vertically inverted direction.

  A collimator lens 2, a cylindrical lens 3, and a rotating polygon mirror 4 are sequentially arranged on the optical path in front of the semiconductor laser 1, and an imaging lens 5 is arranged on the optical path in the reflection direction of the rotating polygon mirror 4. Yes. An aperture stop 8 is provided between the cylindrical lens 3 and the rotary polygon mirror 4. Further, a horizontal synchronization detection optical system 6 and a horizontal synchronization detection sensor 7 are provided at a predetermined portion in the reflection direction of the rotary polygon mirror 4. These are held by an optical box 10 serving as a housing, and are closed by a lid 20. The optical box 10 is provided with positioning pins 11.

  A slit 21 is provided integrally with the lid 20, and the slit 21 is disposed on the optical axis of the horizontal synchronization detecting optical system 6. The lid 20 is provided with a guide hole 22 and a screw hole 23 and is fixed to the optical box 10 with a screw 30.

  FIG. 2 is a top view of the scanning optical apparatus according to the present embodiment. The basic principle of the scanning optical apparatus according to the present embodiment will be described with reference to FIG. For easy understanding, the lid 20 is shown in a removed state.

  The light beam emitted from the semiconductor laser 1 is made into substantially parallel light by the collimator lens 2, the light beam is shaped by the aperture stop 8, is condensed linearly on the rotary polygon mirror 4 by the cylindrical lens 3, and is rotated. The polygon mirror 4 deflects and scans in a predetermined direction perpendicular to the rotation axis, and passes through the imaging lens 5 to form an image on a rotating drum-shaped photoconductor. The light beam that forms an image on the photosensitive member forms an electrostatic latent image along with the main scanning by the rotation of the rotary polygon mirror and the sub-scanning by the rotating drum.

  A part of the light beam scanned by the rotary polygon mirror 4 enters the horizontal synchronization detection optical system 6 and is introduced into the horizontal synchronization signal detector 7 after being regulated by a slit 21 formed integrally with the lid 20. Then, the semiconductor laser 1 starts write modulation by the output signal. In FIG. 2, L1 is the optical axis of the light beam emitted from the semiconductor laser, and L2 is the optical axis of the light beam incident on the horizontal synchronization detection sensor.

  In the scanning optical device according to the present embodiment, as described above, the slit that regulates the scanning direction position of the light beam incident on the horizontal synchronization detection sensor is formed integrally with the lid member that closes the optical box. Therefore, it is possible to adjust the writing position of the scanning line by sliding the lid member in the direction perpendicular to the optical axis L2.

  A scanning line writing position adjustment method in the scanning optical apparatus according to the present embodiment will be described with reference to FIGS. FIG. 3 is a top view of the scanning optical apparatus according to the present embodiment, and FIG. 4 is an enlarged view of the vicinity of the horizontal synchronization detection sensor in the scanning optical apparatus.

  FIG. 3 is a top view of the scanning optical device according to the present embodiment with the lid member attached. A guide hole 22 is provided in the lid 20 at a position corresponding to the positioning pin 11 provided in the optical box 10. The direction of the guide hole 22 is such that the longitudinal direction is perpendicular to the optical axis L2, so that the lid member 20 can be slid in the direction perpendicular to the optical axis L2.

  Next, the scanning line writing position adjustment in the scanning optical apparatus according to the present embodiment will be briefly described with reference to FIG.

  As described above, the lid member 20 in which the slit 21 is integrally formed is slid in the direction orthogonal to the optical axis L2, thereby causing the slit 21 to be orthogonal to the optical axis L2, as indicated by a broken line in FIG. Move to. Accordingly, the timing at which the light beam is incident on the horizontal synchronization detecting sensor 7 is changed by the deflection of the rotary polygon mirror 4, so that the writing position of the scanning line can be adjusted.

  In the assembling process of the scanning optical apparatus according to the present embodiment, as described above, after the scanning member writing adjustment is performed by moving the lid member 20 in the direction orthogonal to the optical axis L2, the fixing screw 30 is fixed. Thus, the lid member 20 is fixed to the optical box 10 to complete the scanning optical device.

  In the scanning optical device according to the present embodiment, the scanning line writing position is adjusted by moving the lid. Therefore, the scanning line writing position is readjusted with the scanning optical device attached to the image forming apparatus. This can be easily performed, and the printing position accuracy in the scanning direction of the image forming apparatus can be improved.

  In the scanning optical device according to the present embodiment, as described above, the scanning line writing position is adjusted by sliding the lid member 20 formed integrally with the slit 21 in a direction perpendicular to the optical axis L2. Therefore, when it becomes necessary to readjust the scanning line writing position, it is not necessary to completely remove the lid member as in the scanning optical apparatus described in the conventional example, and the lid member 20 is only loosened slightly. It is possible to easily readjust the scanning line writing position by sliding. Therefore, when the scanning line writing position is readjusted, the optical components such as the lens are not exposed to the outside air, so that there is no possibility that the optical components are contaminated. After the readjustment, the lid member 20 is fixed to the optical box 10 with the fixing screw 30 as described above.

  Furthermore, in the scanning optical apparatus according to the present embodiment, the scanning line writing position can be easily performed in a state where the scanning optical apparatus is assembled to the image forming apparatus as described above, and the invention is to be solved. As described in the section of the problem, an image forming apparatus with little deviation in scanning line writing position caused by an attachment position error between the optical bench and the scanning optical apparatus can be obtained without greatly degrading the assembling property. It is possible to provide the configuration without complicating.

  In addition, when the configuration according to the present embodiment is applied to a multi-beam scanning optical apparatus, there is also an effect that dot deviation in the scanning direction between the beams can be reduced. In recent years, with the increase in the speed of image forming apparatuses, multi-beam scanning optical apparatuses using a multi-beam semiconductor laser having a plurality of light emitting points as light sources have come to be used. In such a multi-beam scanning optical device, if the straightness of the slit that restricts the light beam incident on the horizontal synchronization signal detection sensor is poor, dot deviation in the main scanning direction between the beams deteriorates. The straightness of the department is important.

  Furthermore, since an optical box serving as a casing of the scanning optical device requires strength, it is generally molded with a resin material containing glass fiber or the like. Therefore, when the slit is formed integrally with the optical box, the straightness of the slit is deteriorated due to the influence of the glass fiber. On the other hand, since the lid member does not require strength as compared with the optical box, the lid member is often formed of an inexpensive material that does not include glass fiber or the like.

  Therefore, in the scanning optical device of the present invention, as described above, the slit is formed integrally with the lid member, so that the straightness of the slit portion can be manufactured with high accuracy, and each beam in the multi-beam scanning optical device can be manufactured. There is also an effect that dot deviation in the scanning direction can be reduced.

<Embodiment 2>
5a and 5b are for explaining a second embodiment of the scanning optical apparatus according to the present invention. FIG. 5A is a perspective view showing the entire scanning optical apparatus according to this embodiment, and FIG. 5B is a perspective view of the lid member of the scanning optical apparatus according to this embodiment as viewed from the opposite direction. Since the basic configuration such as the lenses in the scanning optical apparatus is the same as that of the scanning optical apparatus of the first embodiment, the same components are denoted by the same reference numerals, and detailed description thereof is omitted here.

  Similar to the scanning optical device of the first embodiment, the slit 21 that restricts the light beam incident on the horizontal synchronization signal detection sensor 7 is covered by the lid member 20 so that the scanning line writing position can be adjusted. It is formed integrally with the member 20. Further, the lid member 20 is provided with a rotation reference portion 25 comprising a rotation shaft 25a and a frame portion 25b, and a fitting hole 15 is provided at a position corresponding to the rotation shaft 25a on the bottom surface of the optical box 10. Yes. Further, the lid member 20 is provided with a screw hole 23 and a tool receiving portion 26 used for adjustment.

  FIG. 6 is a top view of the scanning optical apparatus according to the present embodiment.

  As shown in FIG. 6, the above-described rotation reference unit 25 is provided on the optical axis L <b> 2 that is incident on the horizontal synchronization detection sensor. FIG. 7 is a partial sectional view of the rotation reference portion 25 and the slit 21 as seen from the direction of the optical axis L2. As shown in FIG. 7, since the frame portion 25 b is provided at a position corresponding to the optical axis L <b> 2 of the rotation reference portion 25, the rotation reference portion 25 blocks the light beam incident on the horizontal synchronization detection sensor 7. There is nothing.

  Since the scanning optical apparatus according to the present embodiment is configured as described above, the scanning line writing position can be adjusted by rotating the lid member 20 around the rotation reference portion 25.

  The adjustment of the scanning line writing position in the scanning optical apparatus according to the present embodiment will be described with reference to FIG.

  As described above, the lid member 20 is provided with the slit 21 and the rotation reference portion 25, and the fitting hole 15 is provided at a position corresponding to the rotation reference portion 25 of the optical box 10. 20 can be rotated around the rotation reference portion 25. When rotating the lid member 20, the tool receiving portion 26 is held by an adjustment tool or the like, and the lid member 20 is rotationally moved in the direction of the arrow B1. When the lid member 20 is rotated, the position of the slit 21 is also moved in the direction of the arrow B2, so that the timing at which the light beam deflected by the rotary polygon mirror 4 enters the horizontal synchronization detection sensor 7 changes, and the scanning line The writing position can be adjusted. After adjusting the scanning line writing position in this way, the lid member 20 is fixed to the optical box 10 by the fixing screw 30.

  Similar to the scanning optical device of the first embodiment, the scanning optical device according to the present embodiment is also attached to the image forming apparatus because the scanning line writing position can be readjusted without completely removing the lid member. Even in this state, the scanning line writing position can be easily adjusted. In addition, the effect that there is no fear of adhesion of optical components due to the intrusion of dust into the scanning optical device is the same as that of the first embodiment.

  Furthermore, in the scanning optical device of the present embodiment, since the rotation reference portion is provided on the optical axis of the light beam incident on the horizontal synchronization signal detection sensor, the sensitivity of scanning line writing position adjustment can be lowered. It has the effect of being able to.

  In FIG. 7, by increasing the ratio b1 / b2 of the distance b1 from the rotation reference portion 25 to the tool receiving portion 26 and the distance b2 from the rotation reference portion 25 to the slit 21, the scanning line writing by the rotational movement of the lid member 20 is performed. The sensitivity of position adjustment can be lowered. For example, if the lid member 20 is designed so that b1 / b2 = 5, the sensitivity of adjustment to the scanning optical apparatus of the first embodiment can be reduced to 1/5, and the scanning line writing position The workability at the time of adjustment can be greatly improved.

  The present invention can be applied to a scanning optical device used in an image forming apparatus such as a laser printer or a laser facsimile.

1 is a perspective view showing a scanning optical device according to Embodiment 1 of the present invention. 1 is a top view of a scanning optical device according to Embodiment 1 of the present invention. 1 is a top view of a scanning optical device according to Embodiment 1 of the present invention. It is a figure explaining scanning line writing-out adjustment in the scanning optical apparatus concerning Embodiment 1 of this invention. It is a perspective view which shows the scanning optical apparatus which concerns on Embodiment 2 of this invention. It is a perspective view which shows the scanning optical apparatus which concerns on Embodiment 2 of this invention. It is a figure explaining scanning line writing-out adjustment in the scanning optical apparatus concerning Embodiment 2 of this invention. It is a figure which shows the shape of the cover member of the scanning optical apparatus which concerns on Embodiment 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Semiconductor laser 2 Collimator lens 3 Cylindrical lens 4 Rotating polygon mirror 5 Imaging lens 6 Horizontal synchronization detection optical system 7 Horizontal synchronization signal detector 10 Optical box 11 Positioning pin 15 Fitting hole 20 Lid member 21 Slit 22 Guide hole 25 Rotation Reference part 30 Fixed screw

Claims (4)

A light source device, a first imaging optical system that collects a light beam emitted from the light source device, and a rotating polygon mirror that reflects and deflects the light beam that has passed through the first imaging optical system by a deflecting reflection surface A second imaging optical system that optically scans the light beam deflected by the rotary polygon mirror onto the photosensitive member and forms an image as a spot on the photosensitive member, and a signal for detecting a scanning line writing position Horizontal synchronization signal detection means, a horizontal synchronization signal detection optical system for guiding a part of the light beam deflected by the rotary polygon mirror to the horizontal synchronization signal detection means, and light incident on the horizontal synchronization signal detection means In a scanning optical device having a slit for regulating a beam, an optical box serving as a housing for holding them with high accuracy, and a lid member for closing the optical box,
A scanning optical apparatus, wherein the slit is provided integrally with the lid member.   2. The scanning optical apparatus according to claim 1, wherein the lid member is slidable in a direction perpendicular to the optical axis of the light beam incident on the front horizontal synchronization signal detecting means.   2. The scanning optical device according to claim 1, wherein the lid member has a rotation reference portion, and the lid member is rotatable around the rotation reference portion.   The scanning optical device according to claim 1, wherein the light source device is a multi-beam light source device that generates a plurality of light beams.

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