JP2009069304A - Image forming apparatus, and scanning optical apparatus mounted on image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus and scanning optical apparatus, which are high in an optical performance with an inexpensive and easy configuration, by preventing the deterioration of image quality and the generation of noise due to a vibration caused by the instability of the position regulation of the scanning optical apparatus and a supporting frame. <P>SOLUTION: The image forming apparatus includes: the scanning optical apparatus 8; and the supporting frame 9 which supports the scanning optical apparatus 8, wherein a positioning part 31a and a positioning plate 31e are integrally formed on a casing 31. A positioning pin 9a on the supporting frame 9 is force-inserted into the positioning part 31a of the casing 31, the positioning pin 9b is pinched by the positioning plate 31e, and the side faces of the respective positioning members are in press-contact with each other. Thus, the scanning optical apparatus 8 is regulated in its position at the supporting frame 9. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a scanning optical device that scans a laser beam to expose a photosensitive member, and an image forming apparatus equipped with the scanning optical device.

  In a conventional image forming apparatus, a scanning optical device is fixed to a support frame, which is a structure of the image forming device, by screw fastening or the like, and a laser is emitted from the scanning optical device to scan the photosensitive member to form an image. Is done. Therefore, the relative positioning of the scanning optical device and the photosensitive member needs to be accurately performed, and the positioning can be performed by engaging the positioning optical members and structures provided respectively on the scanning optical device and the support frame. Many.

  On the other hand, in an image forming apparatus, there is a case where vibration due to rotation of a deflection device (for example, a polygon mirror device) mounted on a scanning optical device propagates to an optical component or a casing or a support frame in the scanning optical device. It was. Conversely, vibrations from other drive sources outside the scanning optical device may propagate to the scanning optical device via the support frame. Due to this vibration, the scanning position accuracy of the laser light on the photosensitive member is deteriorated, and there is a possibility that the image quality of the image forming apparatus is deteriorated or abnormal noise is generated.

  In addition, as one of the factors affecting the image quality deterioration and abnormal noise generation due to the vibration propagation, there is a fixed (engaged) state between the scanning optical device and the support frame. That is, when the position regulation between the scanning optical device and the support frame is performed stably and firmly, image quality deterioration and abnormal noise generation can be suppressed, and when the position regulation is unstable Conversely, image quality deterioration and abnormal noise are likely to occur.

As a countermeasure against such a problem, a technique in which a base for fixing the scanning optical device to the support frame and a positioning pin are configured coaxially is known. Accordingly, when the fixing unit for fixing the scanning optical device to the support frame and the positioning unit are separated from each other, the amount of displacement due to vibration generated due to the contact state between the positioning unit and the support frame is reduced. It can be reduced (Patent Document 1). Further, a technique for reducing vibration by configuring an elastic body around the positioning portion between the scanning optical device and the support frame is known (Patent Document 2).
JP 2004-212591 A JP 2005-059380 A

  However, none of the inventions described in Japanese Patent Application Laid-Open Nos. 2004-225991 and 2005-59380 stabilize the contact state between the scanning optical device and the positioning portion of the support frame. In other words, the above-described conventional example is not necessarily configured to reduce the vibration itself generated due to the unstable positioning of the scanning optical device and the support frame.

In the invention described in Japanese Patent Application Laid-Open No. 2004-212591, it is necessary to strictly manage the shape dimensional accuracy and position accuracy of the positioning portions of the scanning optical device and the support frame, and the materials of the housing and the support frame are limited. The structure and structure become complicated. Further, the scanning optical device is fixed to the support frame from the support frame side, and assemblability and maintainability are deteriorated. The invention described in Japanese Patent Application Laid-Open No. 2005-59380 is to absorb vibration by inserting an elastic body around the positioning portion, and it is necessary to consider variation in vibration frequency to be reduced. It is also necessary to increase the accuracy of the shape and dimensions.

  The present invention has been made in view of the above-mentioned unsolved problems of the prior art. The object of the invention according to the present application is to suppress the deterioration of image quality and the generation of abnormal noise due to vibration caused by the instability of the position regulation of the scanning optical device and the support frame, and to achieve high optical performance with an inexpensive and easy configuration. An apparatus and an image forming apparatus are provided.

The present application employs the following means in order to solve the above problems. That is, a light source unit that emits laser light, a deflecting unit that deflects and scans the laser light on a photosensitive member, and an imaging unit that forms an image of the laser light on the photosensitive member are mounted on a housing. A scanning optical device,
An image forming apparatus comprising: a support frame that supports the scanning optical device and has a plurality of position restricting portions that restrict the position of the scanning optical device with respect to the photoconductor.
The housing is provided with a plurality of positioning portions that engage with each of the position restricting portions in the support frame,
At least one of the plurality of positioning portions is engaged with the position restricting portion in a state in which the side surface is in pressure contact with the side surface of the position restricting portion.

  In the present invention, the positioning portion of the scanning optical device and the position restriction portion of the support frame are always engaged with each other by pressing the side surfaces at one or more locations. It is possible to stabilize the contact state at the engaging portion and suppress the occurrence of vibration. Further, at that time, it is possible to suppress the material, the structure, and the assembling property and maintainability of the scanning optical device.

  The best mode for carrying out the present invention will be exemplarily described in detail below with reference to the drawings.

  FIG. 1 is a cross-sectional view of an image forming apparatus according to the present embodiment, and FIGS. 2 to 4 are a perspective view and a cross-sectional view of the scanning optical apparatus according to the present embodiment, as drawings that best represent the features of the present invention.

  A schematic configuration of the image forming apparatus according to the present exemplary embodiment will be described with reference to FIG. An exterior portion 2 including a door 3 that is opened and closed is formed on the outer periphery of the image forming apparatus 1. By opening and closing the door 3, a process cartridge 6 (described later) can be attached to and detached from the image forming apparatus 1. At the bottom of the image forming apparatus 1, a cassette 4 for storing a sheet material S for forming an image is provided. In the vicinity of the cassette 4, a conveying means 5 comprising a roller group of 5 a to 5 c is provided, and the sheet material S discharged from the cassette 4 can be conveyed to the vicinity of the process cartridge 6.

  The process cartridge 6 is a device for forming an image on the electrophotographic photoreceptor 6a. The electrophotographic photosensitive member 6 a of the process cartridge 6 is irradiated with a laser beam J corresponding to image information from the scanning optical device 8. That is, the laser beam J emitted from the scanning optical device 8 is irradiated while being scanned in the axial direction of the electrophotographic photosensitive member 6a, and the electrophotographic photosensitive member 6a is rotated to electrostatically apply it onto the electrophotographic photosensitive member 6a. A latent image is formed.

  The scanning optical device 8 is fixed to a support frame 9 that is a part of a frame (not shown) of the image forming apparatus 1. At that time, the scanning optical device 8 and the electrophotographic photosensitive member 6a are positioned and fixed so that the relative position between them is appropriate.

  Next, a basic operation of the image forming apparatus 1 having the above configuration will be described. The sheet material S loaded and stored in the cassette 4 is sequentially conveyed from the upper level toward the process cartridge 6 which is an image forming unit by the conveying unit 5. The surface of the electrophotographic photosensitive member 6a built in the process cartridge 6 is uniformly charged by a charging device (not shown). On the surface of the charged electrophotographic photosensitive member 6a, the laser beam J emitted from the scanning optical device 8 corresponding to the image information is irradiated to form an electrostatic latent image. The electrostatic latent image is developed as a toner image by developing means (not shown), and then transferred onto the sheet material S by the transfer means 7.

  Next, the sheet material S is conveyed to the fixing unit 10, and the toner image on the sheet material S is heated by the fixing unit 10 and fixed to the sheet material. Then, the sheet material S is discharged to the discharge stacking unit 11 by the transport unit 11a, and the image forming process is completed.

  Next, details of the scanning optical device 8 and its position restriction will be described with reference to FIGS. The scanning optical device 8 includes a light source device 21 as light source means having a semiconductor laser (not shown) as a light source. Laser light emitted from the light source device 21 is irradiated to the polygon mirror 24 after passing through the collimator lens 22 and the cylindrical lens 23.

  When the polygon mirror 24 rotates in the deflection scanning device 25, the reflection direction of the laser beam by the polygon mirror 24 is deflected. The laser light reflected by the polygon mirror 24 passes through the imaging lenses 26 and 27, is further changed in direction by the reflecting mirror 28, and is irradiated onto the above-described electrophotographic photosensitive member 6a. Reference numeral 29 denotes a scanning start signal detector, and 30 denotes a reflection mirror that guides laser light to the scanning start signal detector. The optical system constituted by each optical element described here corresponds to the imaging means in the present embodiment. The deflection scanning device 25 corresponds to a deflection unit.

  The scanning optical device 8 is configured by arranging and fixing these optical elements and electronic elements on a casing 31 molded with resin. A lid 32 is attached to the housing 31 to prevent dust from entering the scanning optical device 8. In addition, a positioning portion 31a having a positioning port 31b and a positioning plate 31e are provided on the back side of the surface of the housing 31 on which the above-described optical elements and electronic elements are arranged. The positioning portion 31a has a substantially cylindrical shape, and four slits 31c are formed at intervals of about 90 degrees in the axial direction of the cylinder. The slit 31c is a slit portion in the present embodiment.

  The scanning optical device 8 is fixed on the support frame 9 at four positions by fixing screws 33. The support frame 9 is provided with two positioning pins 9a and 9b. The positioning pins 9a and 9b are integrally formed with the support frame 9, and the position of the scanning optical device 8 on the support frame 9 is regulated by engaging the positioning portion 31a and the positioning plate 31e. As a result, the position of the scanning optical device 8 relative to the electrophotographic photosensitive member 6a is also restricted. The support frame 9 is formed with an opening 9c through which the laser light emitted from the scanning optical device 8 passes. Here, the two positioning pins 9a and 9b correspond to a plurality of position restricting portions and pin portions in this embodiment. Further, the positioning part 31a and the positioning plate 31e correspond to the positioning part in this embodiment. In this embodiment, the positioning portion 31a corresponds to one of the positioning portion and the position restricting portion and has a substantially cylindrical shape and a slit portion. In addition, the positioning pin 9a has a convex pin portion corresponding to the other of the positioning portion and the position restricting portion.

Next, basic adjustment and assembly in the scanning optical device 8 will be described. The light source device 21 is attached to the housing 31 in a state where the optical adjustment of the semiconductor laser (not shown) and the collimator lens 22 is completed in advance, and the cylindrical lens 23 is temporarily arranged on the housing 31. The deflection scanning device 25, the imaging lenses 26 and 27, the reflection mirror 28, and the scanning start signal detector 29 on which the polygon mirror 24 is mounted are positioned at predetermined positions on the housing 31 and fixed by screws or fixtures (not shown). .

  The focal position of the laser beam J is adjusted by moving the cylindrical lens 23 in the optical axis direction of the laser beam after passing through the collimator lens 22. Further, the reflection mirror 30 is adjusted and fixed so that the laser beam deflected and scanned by the polygon mirror 24 is incident on the scanning start signal detector 29. As described above, the optical adjustment of the scanning optical device 8 is completed, and the casing 31 is sealed by the lid 32, whereby the scanning optical device 8 is configured.

  Next, position regulation and fixing of the scanning optical device 8 to the support frame 9 will be described. As described above, the support frame 9 is integrally formed with positioning pins 9a and 9b for restricting the relative position of the scanning optical device 8 with respect to the reference position of the electrophotographic photosensitive member 6a. The positioning pins 9a and 9b are respectively engaged between the positioning portion 31a of the scanning optical device 8 and the two positioning plates 31e, so that the scanning optical device 8 is positioned with respect to the electrophotographic photosensitive member 6a. At this time, the inner diameter of the positioning port 31b of the positioning portion 31a and the distance between the two positioning plates 31e are set to be slightly smaller than the outer diameters of the positioning pins 9a and 9b. Accordingly, the four segments 31d and the two positioning plates 31e of the positioning portion 31a are surely in contact with the positioning pins 9a and 9b. Then, the scanning optical device 8 is fixed to the support frame 9 with a fixing screw 33.

  As described above, according to the present embodiment, the positioning portion 31a and the two positioning plates 31e that are engaged with the positioning pins 9a and 9b are formed in the resin casing so as to be elastically deformable. The pins 9a and 9b can be reliably brought into contact with each other. Specifically, the positioning pin 9a and the positioning portion 31a are at least four or more in the four sections 31d between the slit 31c and the side wall of the positioning pin 9a and the inner wall (side surface) of the positioning port 31b of the positioning portion 31a (Therefore, two or more locations) are in pressure contact. Further, the positioning pin 9b and the positioning plate 31e are in pressure contact with the side surface of the positioning pin 9b and the side surface of the positioning plate 31e at at least two places.

  Accordingly, at least the engagement between the positioning portion 31a engaged with the positioning pins 9a and 9b and the two positioning plates 31e can be stabilized, so that wear and damage of the resin portion can be suppressed. Furthermore, since the positioning portion 31a and the two positioning plates 31e can be configured integrally with the resin casing 31 of the scanning optical device 8, the design freedom is high and the configuration can be reduced.

  In this embodiment, when the positioning pin 9a is engaged with the positioning port 31b and when the positioning pin 9b is engaged with the positioning plate 31e, an elastic member such as vibration damping rubber is interposed therebetween. Also good. If it does so, it will become possible to suppress generation | occurrence | production of a vibration more reliably.

  In this embodiment, the positioning portion 31a is formed with four slits 31c extending in the axial direction of the cylinder at intervals of about 90 degrees, but the shape and number of slits are not limited thereto. . Of course, a slit extending in a direction perpendicular to the axis of the cylinder may be formed.

Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 5 is an explanatory diagram of the scanning optical device, FIG. 6 is an assembly explanatory diagram of the scanning optical device, FIG. 7 is a detailed diagram of a positioning portion of the scanning optical device, and FIG. The same configurations and operations as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the description thereof is omitted.

  In the scanning optical device 8 according to the present embodiment, a second positioning unit in which a second positioning pin 51a having a second positioning port 51b is formed on the back side of the surface of the housing 31 on which the optical element and the electronic element are arranged. 51 and a third positioning pin 52 are provided. Here, the second positioning pin 51a has a substantially cylindrical shape, and two slits 51c are formed in the axial direction of the cylinder. In addition, a cylindrical cylinder base 51d formed slightly lower than the second positioning pin 51a is formed around the second positioning pin 51a in the present embodiment. In addition, a female screw portion 51e that can be screwed with a male screw is formed at the bottom of the hole 51b of the second positioning pin 51a. Here, the second positioning pin 51a corresponds to a cylindrical portion in the present embodiment. The cylindrical table 51d corresponds to the second cylindrical portion.

  On the other hand, a circular first positioning hole 61 and an elongated second positioning hole 62 are formed in the support frame 9 in this embodiment. In the present embodiment, a fixing cap 70 for positioning and fixing the scanning optical device 8 to the support frame 9 is prepared. The fixed cap 70 is provided with a cap portion 70a, an insertion shaft 70b to be press-fitted into the second positioning port 51b, and a male screw portion 70c that is screwed into the female screw portion 51e. ing. In addition, a second cylindrical base 70d is formed around the insertion shaft 70b so that the inner diameter side surrounds the insertion shaft 70b in a cylindrical shape. Here, the 1st positioning hole 61 is corresponded to the position control hole in a present Example. The fixing cap 70 corresponds to a fixing member. The second cylindrical table 70d corresponds to a substantially cylindrical fixing cylindrical portion.

  In the above configuration, when the position of the scanning optical device 8 with respect to the support frame 9 is restricted, the second positioning pin 51 a of the second positioning portion 51 is engaged with the first positioning hole 61 of the support frame 9. Further, the third positioning pin 52 engages with the second positioning hole 62 of the support frame 9. Thereby, the scanning optical device 8 is positioned with respect to the support frame 9. The scanning optical device 8 is fixed to the support frame 9 by a fixing screw (not shown). Next, the insertion shaft 70 b of the fixed cap 70 is press-fitted into the second positioning port 51 b of the second positioning portion 51. Then, the both ends of the slit 51 c are deformed to the outer diameter side by the insertion shaft 70 b of the fixed cap 70, and the side surfaces thereof are pressed against the side surfaces of the first positioning holes 61 of the support frame 9.

  Further, the second positioning portion 51 and the fixing cap 70 are fixed with the support frame 9 interposed therebetween by the female screw portion 51 e of the second positioning portion 51 and the male screw portion 70 c of the fixing cap 70. At this time, more specifically, the cylindrical base 51d of the second positioning portion 51 and the second cylindrical base 70d of the fixing cap 70 cooperate with each other by the screw fastening force, so that the peripheral portion of the first positioning hole 61 in the support frame 9 is It will be in the state clamped firmly.

  As described above, in the present embodiment, the position of the second positioning portion 51 of the scanning optical device 8 is firmly restricted by the fixing cap 70 in the vertical direction as well as in the horizontal (parallel) direction with respect to the support frame 9. Thereby, the vibration in the second positioning portion 51 can be more reliably suppressed, and the vibration of the casing 31 itself of the scanning optical device 8 can be suppressed.

  In this embodiment, when the second positioning pin 51a is engaged with the first positioning hole 61, an elastic member such as vibration damping rubber may be interposed therebetween. If it does so, it will become possible to suppress generation | occurrence | production of a vibration more reliably.

In the present embodiment, the second positioning pin 51a is formed with two slits 51c extending in the axial direction of the cylinder, but the shape and number of the slits are not limited thereto. Of course, a slit extending in a direction perpendicular to the axis of the cylinder may be formed.

1 is a cross-sectional view as viewed from the side of an image forming apparatus in Embodiment 1 of the present invention. Sectional drawing seen from the upper surface of the scanning optical apparatus in Example 1 of this invention. 1 is a perspective view of a scanning optical device in Embodiment 1 of the present invention. FIG. 4A is a cross-sectional view of the scanning optical device according to the first embodiment of the present invention viewed from the side. FIG. 4B is a cross-sectional view of the engaging portion between the scanning optical device and the support frame according to the first embodiment of the present invention as viewed from the support frame side. FIG. 5A is a cross-sectional view seen from the side of the scanning optical device according to the second embodiment of the present invention. FIG. 5B is an enlarged view of an engaging portion between the scanning optical device and the support frame in Embodiment 2 of the present invention. FIG. 6 is a perspective view of a scanning optical device in Embodiment 2 of the present invention. The enlarged view of the 2nd positioning part of the scanning optical apparatus in Example 2 of this invention. The enlarged view of the fixed cap in Example 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus 6a ... Electrophotographic photosensitive member 8 ... Scanning optical device 9 ... Support frame 9a, 9b ... Positioning pin 21 ... Light source device 26, 27 ... Imaging Lens 31 ... Case 31a ... Positioning portion 31b ... Positioning port 31c ... Slit 31d ... Section 31e ... Positioning plate 51 ... Second positioning portion 51a ... Second positioning Pin 51b ... Second positioning port 51c ... Slit 51d ... Cylindrical base 51e ... Female thread part 52 ... Third positioning pin 61 ... First positioning hole 62 ... Second positioning Hole 70 ... Fixed cap 70a ... Cap part 70b ... Insertion shaft 70c ... Male thread part 70d ... Second cylindrical base

Claims (7)

Scanning comprising a light source means for emitting laser light, deflection means for deflecting and scanning the laser light on the photosensitive member, and imaging means for forming an image of the laser light on the photosensitive member. An optical device;
An image forming apparatus comprising: a support frame that supports the scanning optical device and has a plurality of position restricting portions that restrict the position of the scanning optical device with respect to the photoconductor.
The housing is provided with a plurality of positioning portions that engage with each of the position restricting portions in the support frame,
At least one of the plurality of positioning portions is engaged with the position restricting portion in a state where a side surface thereof is in pressure contact with the side surface of the position restricting portion.   One of the positioning portion and the position restricting portion that are engaged in a state where the side surfaces are in pressure contact has a cylindrical shape, and has a slit portion extending in a direction parallel or perpendicular to the axis of the cylinder. The image forming apparatus according to claim 1, wherein:   The other of the positioning part and the position restricting part that engages in a state in which the side surface is press-contacted has a convex pin part, and the pin part is press-fitted into a cylinder having the slit part. The image forming apparatus according to claim 2, wherein the positioning unit and the position regulating unit are engaged with each other.   The at least one of the plurality of positioning portions is engaged with the position restricting portion in a state in which the side surface is pressed against the side surface of the position restricting portion at two or more locations. The image forming apparatus described. In the positioning portion that engages with the position restricting portion in a state where the side surface is pressed against the side surface of the position restricting portion,
A cylindrical part having a cylindrical shape and formed with a slit part extending in a direction parallel or perpendicular to the axis of the cylinder;
A second cylindrical portion having a cylindrical shape and a height lower than the cylindrical portion so as to surround the cylindrical portion;
The position restricting portion that engages with the positioning portion is a position restricting hole provided in the support frame,
A fixing member that is press-fitted into the cylindrical portion in a state where the cylindrical portion of the positioning portion is inserted into the position restricting hole of the position restricting portion when restricting the position of the scanning optical device;
The fixing member expands the cylindrical portion by being press-fitted into the cylindrical portion, presses the side surface of the cylindrical portion and the side surface of the positioning hole, and when the press-fitted into the cylindrical portion, the second member 2. The image forming apparatus according to claim 1, further comprising a cylindrical fixing cylindrical portion that sandwiches a peripheral portion of the position restricting hole in the support frame in cooperation with a distal end of the cylindrical portion.   The image forming apparatus according to claim 1, wherein the side surface of the positioning unit and the side surface of the position regulating unit are pressed against each other via an elastic member.   The scanning optical apparatus mounted in the image forming apparatus of any one of Claims 1-6.

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