JP2011158566A - Optical scanner and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce noise when moving a holding member by facilitating manufacture of the holding member possessed by an automatic cleaning mechanism and further improving size precision of the holding member in an optical scanner. <P>SOLUTION: The optical scanner has a spiral groove, and an axial length of a crest part is longer than the axial length of a trough part on the crest part and the trough part formed with the spiral groove. The optical scanner has a screw shaft 101 rotated with an electric motor, a projection part inserting the screw shaft and slidably fitted in the spiral groove on an inner wall face, and the holding member 103 for holding a cleaning member wiping the surface of a dust-proof glass. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an optical scanning device and an image forming apparatus.

Conventionally, an optical scanning device, which is a main component of an image forming unit incorporated in an image forming apparatus such as a copying machine or a multifunction peripheral, has a light beam guided inside and a light beam guided. A housing having an injection port for injection is provided. In general, a dust-proof glass for preventing foreign matter from entering the inside of the housing is fitted into the injection port formed in the housing.
Foreign substances that are prevented from entering the housing adhere to the dust-proof glass. When foreign matter adheres to the dust-proof glass, the optical properties of the dust-proof glass deteriorate and the quality of image formation decreases, so some optical scanning devices have an automatic cleaning mechanism that cleans the surface of the dust-proof glass. is there.

  As shown in Patent Literatures 1 to 3, such an automatic cleaning mechanism includes a holding member having a cleaning member that is in sliding contact with the surface of the dust-proof glass, and a screw shaft that is rotationally driven by a motor that reciprocates the holding member. And. In this automatic cleaning mechanism, when the image forming apparatus is started up or when printing reaches a predetermined number, the motor is driven and the screw shaft is rotated so that the cleaning member slides and cleans the surface of the dust-proof glass. It is configured.

JP 2008-194961 A JP 2009-115932 A JP 2009-169133 A

However, in the automatic cleaning mechanism attached to the housing of the conventional optical scanning device, the axial length of the valley is larger than the axial length of the peak in the peak and valley formed by the spiral groove. Since it is formed, the screw part of the holding member provided with the cleaning member corresponding to the valley portion becomes large, and there is a drawback that it is difficult to manufacture the holding member.
In addition, since it is difficult to manufacture the holding member, the dimensional error of the screw portion becomes large. As a result, in order to realize smooth movement of the holding member, the groove width of the spiral groove is sufficiently wider than the width of the screw portion. It is necessary to secure. For this reason, the clearance gap between a thread part and the side wall of a spiral groove becomes large depending on a place, and the noise at the time of moving a holding member will become large.

  The present invention has been made in view of the above-described problems. In the optical scanning device, the holding member included in the automatic cleaning mechanism is easily manufactured, and the holding member is moved by improving the dimensional accuracy of the holding member. It aims at reducing the noise when making it.

  The present invention adopts the following configuration as means for solving the above-described problems.

  The first invention is an optical scanning device comprising a housing having an exit for emitting a light beam, a dust-proof glass covering the exit, and an automatic cleaning mechanism for cleaning the surface of the dust-proof glass. The cleaning mechanism includes a spiral spiral groove, and the axial length of the peak portion is longer than the axial length of the valley portion at the peak portion and the valley portion formed by the spiral groove. A screw shaft that is driven to rotate, a protrusion that is slidably fitted into the spiral groove on the inner wall surface of the screw shaft, and a cleaning member that wipes the surface of the dust-proof glass are held. And a holding member.

  According to a second aspect, in the first aspect, a guide groove extending along a moving direction of the holding member is formed in the housing, and the holding member includes a protrusion inserted into the guide groove. The configuration is adopted.

  According to a third aspect of the present invention, there is provided an optical scanning device that emits and scans a light beam, a photosensitive member on which an electrostatic latent image is formed by irradiation with the light beam, and developing the electrostatic latent image. The image forming apparatus includes a developing device that forms a toner image, and the optical scanning device according to the first or second invention is used as the optical scanning device.

  According to the present invention, the axial length of the peak portion is set to be longer than the axial length of the valley portion at the peak portion and the valley portion formed by the spiral groove of the screw shaft. For this reason, the screw part of a holding member can be made smaller than before, and manufacture of a holding member can be performed easily. As a result, the dimensional accuracy of the holding member can be improved, and noise when the holding member is moved can be reduced.

1 is a cross-sectional view illustrating a schematic configuration of a copying machine according to an embodiment of the present invention. It is a perspective view when the laser scanning unit with which the copying machine in one Embodiment of this invention is provided is seen from the downward direction. FIG. 3 is a detailed view of a screw shaft included in the copying machine according to the embodiment of the present invention. 1 is a perspective view of a holding member provided in a copying machine according to an embodiment of the present invention. 1 is a perspective view of a state in which a screw shaft is inserted into a holding member provided in a copying machine according to an embodiment of the present invention. FIG. 3 is an enlarged front view showing a part of a holding member provided in the copying machine according to the embodiment of the present invention.

  Hereinafter, an embodiment of an optical scanning device and an image forming apparatus according to the present invention will be described with reference to the drawings. In the following drawings, the scale of each member is appropriately changed in order to make each member a recognizable size. In the following description, a copying machine will be described as an example of the image forming apparatus of the present invention.

  FIG. 1 is a cross-sectional view showing a schematic configuration of a copying machine P according to the present embodiment. As shown in this figure, the copier P of this embodiment includes an image reading unit 1 that reads an image of a document, and a printing unit 2 that prints on a recording sheet (recording medium) based on the read image data. ing.

  The image reading unit 1 irradiates an image of a document with light and receives reflected light to read the image of the document as image data. The image reading unit 1 receives light returned from the light source device or the document that irradiates the document with light. It includes a light receiving sensor that receives light and converts it into image data.

  The printing unit 2 includes a belt unit 6, an image forming unit 7, a paper feed cassette 8, a paper feed tray 9, a secondary transfer unit 10, a fixing unit 11, a paper discharge tray 12, and a conveyance path 13. It has.

The belt unit 6 transfers the toner image formed in the image forming unit 7 and conveys the transferred toner image. The belt unit 6 includes an intermediate transfer belt 61 to which the toner image is transferred from the image forming unit 7, and an intermediate transfer belt 61. A transfer roller 61 is provided, and a driving roller 62 that drives the transfer belt 61 endlessly, a driven roller 63, and a tension roller 64 are provided.
The intermediate transfer belt 61 is stretched around a driving roller 62, a driven roller 63, and a tension roller 64.
The drive roller 62 is connected to a drive unit having a drive source such as a motor, and rotates while applying a grip force to the intermediate transfer belt 61.
The driven roller 63 is driven to rotate following the rotational drive of the drive roller 62.
The tension roller 64 is a kind of driven roller that is driven to rotate by the rotational driving of the driving roller 62, and has a spring mechanism to apply tension to the intermediate transfer belt 61.
Further, the belt unit 6 is provided with a cleaning unit (not shown) so that the toner remaining on the intermediate transfer belt 61 is removed.

  The image forming unit 7 is provided corresponding to each color of yellow (Y), magenta (M), cyan (C), and black (BK), and forms a toner image of each color. These image forming units 7 are arranged along the intermediate transfer belt 61.

Each image forming unit 7 includes a photoreceptor 71, a charger 72, a laser scanning unit (optical scanning device) 73, a developing device 74, a primary transfer roller 75, a cleaning device 76, a static elimination device (not shown), and the like. Have
The photosensitive member 71 is formed in a cylindrical shape, and an electrostatic latent image and a toner image based on the electrostatic latent image are formed on the peripheral surface thereof. The charger 72 is disposed to face the photoconductor 71 and charges the peripheral surface of the photoconductor 71. The laser scanning unit 73 scans the laser light emitted based on the image data in the print format on the peripheral surface of the charged photoreceptor 71. The developing device 74 develops a toner image based on the electrostatic latent image on the circumferential surface of the photoreceptor 71 by supplying toner to the circumferential surface of the photoreceptor 71. The primary transfer roller 75 is disposed opposite to the photoreceptor 71 with the intermediate transfer belt 61 interposed therebetween, and primarily transfers the toner image developed on the photoreceptor 71 to the intermediate transfer belt 61. The cleaning device 76 removes toner remaining on the photoreceptor 71 after the primary transfer.

The paper feed cassette 8 can be pulled out with respect to the apparatus main body and accommodates storage paper. The paper feed tray 9 is openable and closable with respect to the apparatus main body, and stores storage paper.
The secondary transfer unit 10 performs secondary transfer of the image formed on the intermediate transfer belt 61 to a storage medium. The secondary transfer unit 10 sandwiches the drive roller 62 that drives the intermediate transfer belt 61 and the intermediate transfer belt 61 therebetween. The drive roller 62 and the secondary transfer roller 10a are arranged to face each other.
The fixing unit 11 fixes the toner image secondarily transferred onto the storage medium to the recording paper, and includes a heating roller that fixes the toner image to the recording paper by applying pressure and heating.
The transport path 13 includes a pickup roller 13 a that unloads the storage paper from the paper feed cassette 8, a paper feed roller 13 b that transports the storage medium, a paper discharge roller 13 c that discharges the storage medium to the paper discharge tray 12, and the like.

  The copying machine P of the present embodiment having such a configuration acquires image data in the image reading unit 1 as described above, and the printing unit 2 prints on recording paper based on the image data.

Next, a laser scanning unit (LSU) 73 in the copying machine P of this embodiment will be described with reference to FIG. FIG. 2 is a perspective view showing a schematic configuration of the laser scanning unit, with the upper cover removed.
Since each laser scanning unit 73 has the same configuration, only one laser scanning unit 73 will be described in the following description.

The laser scanning unit 73 includes a housing 31. The housing 31 is made of a synthetic resin and is formed into a hollow body having a predetermined volume space inside. In addition, a light beam generator, a polygon mirror, a polygon motor, an optical element, and the like are installed inside the housing 31. Then, the laser scanning unit 73 scans the light beam on the photosensitive member 71 while guiding and emitting the light beam emitted from the light beam generator inside the housing.
Note that an electrostatic latent image is formed on the photoconductor 71 by irradiating the photoconductor 71 with the light beam emitted from the laser scanning unit 73.

  The housing 31 includes an exit port 31a for emitting a light beam guided inside. The laser scanning unit 73 includes a dustproof glass 200 that is fitted into the injection port 31a. The dust-proof glass 200 prevents foreign matter from entering the housing 31.

  As shown in FIG. 2, the laser scanning unit 73 includes an automatic cleaning mechanism 100 attached to the outside of the housing 31. This automatic cleaning mechanism 100 cleans the surface of the dustproof glass 200.

Hereinafter, the automatic cleaning mechanism 100 attached to the housing 31 will be described in detail with reference to FIGS.
FIG. 2 is a bottom view of the laser scanning unit 73 shown in FIG. 1 when viewed from the photoreceptor 71 side. The automatic cleaning mechanism 100 is applied to the photoreceptor 71 of the box-shaped housing 31 of the laser scanning unit 73. It is provided on the opposite surface.

The automatic cleaning mechanism 100 includes a screw shaft 101, a motor 102, and a holding member 103.
The screw shaft 101 is formed a little longer than the length of the dustproof glass 200 in the longitudinal direction, and presents a bar screw in which a spiral of peak portions 101a and valley portions 101b as shown in FIG. ing.
That is, in the present embodiment, the screw shaft 101 includes a spiral groove 300. As shown in FIG. 3, the screw shaft 101 is formed with a crest 101 a and a trough 101 b formed by the presence of the spiral groove 300.

And in the peak part 101a and trough part 101b of the screw shaft 101, the axial direction length (length in the extension direction of a screw shaft) L1 of the peak part 101a is set longer than the length L2 of the trough part 101b. .
Note that the spiral pitch of the spiral groove 300 is set to be relatively large at the center portion of the screw shaft 101 and relatively small toward the both end portions of the screw shaft 101.

  The screw shaft 101 is provided adjacent to the dustproof glass 200 and parallel to the longitudinal direction of the dustproof glass 200. The screw shaft 101 is supported by being pivotally supported by attachment pieces 31 b and 31 c that are integrally formed on the housing 31 at both ends.

The motor 102 is provided in the housing 31 on one end side (right end side in FIG. 2) of the screw shaft 101, and is connected to one end side of the screw shaft 101 via a gear mechanism (not shown). The motor 102 is controlled by a control unit (not shown) of the copying machine P so that the screw shaft 101 can rotate forward or backward.
That is, in this embodiment, the screw shaft 101 is rotationally driven by the motor 102.

The holding member 103 has a boss portion 104 into which the screw shaft 101 is inserted, and arm portions 105 a and 105 b that hold the cleaning member 107.
The boss portion 104 is provided with a through hole 104a through which the screw shaft 101 is inserted, and a screw portion 104b (fitted to the valley portion 101b of the screw shaft 101 is formed in a part of the inner peripheral wall of the through hole 104a. (Protruding part) is provided.
The threaded portion 104b is formed in a range that does not exceed 0.5 of the inner circumference of the through hole 104a. Preferably, as shown in FIG. 6, the length is about 0.25. When the screw portion 104b is about 0.25 rounds, the screw shaft 101 can be smoothly matched.

  The holding member 103 is provided with a buffer member 104c made of a spring. The buffer member 104 c extends to both the axial direction side of the screw shaft 101 with the center position of the holding member 103 as the center, and the tip positions thereof are determined so as to slightly protrude from the holding member 103. The tip positions of the buffer members 104c are determined so as to face the mounting pieces 31b and 31c of the housing 31.

  A pair of columnar protrusions 106 a and 106 b provided at a predetermined interval in the axial direction of the screw shaft 101 are provided on the bottom of the boss 104, that is, the housing 31 of the boss 104. These protrusions 106a and 106b are configured to be inserted into guide grooves 31d provided in the housing 31 along the axial direction of the screw shaft 101 (the moving direction of the holding member 103) (see FIG. 2).

  The arm portions 105 a and 105 b are provided to extend from both sides of the boss portion 104 in a direction orthogonal to the longitudinal direction of the screw shaft 101. The tip portions of the arm portions 105a and 105b are respectively slid by guide bars 31e and 31f provided in the housing 31 with the dustproof glass 200 interposed therebetween and parallel to the longitudinal direction of the dustproof glass 200. (See FIG. 2).

  Of the arm portions 105a and 105b, the arm portion 105a on the dust-proof glass 200 side is provided with a plate-shaped cleaning member 107 whose tip portion slides on the surface of the dust-proof glass 200. This cleaning member 107 is replaceably provided on the arm portion 105a.

  Next, the cleaning operation of the automatic cleaning mechanism 100 having the above configuration will be described. When the copying machine P is started up or before printing reaches a predetermined number, the holding member 103 has one end side of the screw shaft 101 (hereinafter, the right end side in FIG. 2 will be described as one end side) as a home position.

When the cleaning timing comes, the holding member 103 is driven to rotate the screw shaft 101, thereby moving the holding member 103 to the other end side (left end side in FIG. 2). FIG. 2 shows a state in the middle of this movement.
The movement of the holding member 103 is performed very smoothly because the arm portions 105a and 105b are guided by the guide bars 31e and 31f and the protrusions 106a and 106b are guided by the guide groove 31d.
And since the cleaning member 107 slidably contacted with the surface of the dust-proof glass 200 via the arm portion 105 a is attached to the holding member 103, the surface of the dust-proof glass 200 is cleaned as the holding member 103 moves. The

Here, at both ends of the screw shaft 101, the spiral pitch of the screw shaft 101 is relatively small and gradually biased. For this reason, the moving speed of the holding member 103 decreases as it goes beyond the center of the screw shaft 101 toward one end (the other end).
Then, the buffer member 104c made of a spring provided on the holding member 103 is loosely in contact with the attachment piece 31b of the housing 31, and it is detected by a sensor (not shown) that the holding member 103 is positioned on the other end side. When the sensor detects that the holding member 103 is positioned on the other end side, the rotation of the motor 102 is stopped, and then the reverse rotation of the motor 102 is started.

Due to the reverse rotation of the motor 102, the holding member 103 is moved from the other end side of the screw shaft 101 to one end side. The cleaning member 107 also wipes the dust-proof glass 200 by the movement of the holding member 103 and the dust-proof glass 200 is cleaned.
Also here, since the spiral pitch of the spiral groove 300 gradually deviates on one end side of the screw shaft 101, the moving speed decreases as the holding member 103 moves beyond the center of the screw shaft 101 toward the one end side.
Then, the buffer member 104c provided on the holding member 103 is loosely in contact with the mounting piece 31c of the housing 31, and it is detected by the sensor (not shown) that the holding member 103 is positioned on one end side. When the sensor detects that the holding member 103 is positioned on one end side, the rotation of the motor 102 is stopped and the cleaning operation is finished.

  According to the laser scanning unit 73 and the copying machine P in the present embodiment as described above, the axial length L1 of the peak portion 101a is the peak portion 101a and the valley portion 101b formed by the spiral groove 300 of the screw shaft 101. It is set longer than the axial length L2 of the valley 101b. For this reason, the screw part 104b of the holding member 103 can be made smaller than before, and the holding member 103 can be manufactured easily. As a result, the dimensional accuracy of the holding member 103 can be improved and the width of the spiral groove 300 can be made closer to the screw portion 104b. Therefore, the clearance gap between the screw part 104b and the side wall of the spiral groove 300 can be made small, and the noise at the time of moving the holding member 103 can be reduced.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

For example, in the above-described embodiment, the configuration in which the laser scanning unit 73 that is an example of the optical scanning device of the present invention is mounted on a copying machine that is one of the image forming apparatuses has been described.
However, the optical scanning device of the present invention is not limited to this, and may be mounted on a device such as a measuring instrument or an inspection device in addition to an image forming apparatus such as a copying machine.

  P: Copying machine (image forming apparatus), 73: Laser scanning unit (optical scanning apparatus), 31: Housing, 31a: Injection port, 31b, 31c ... Mounting piece, 31d: Guide groove, 31e, 31f: guide bar, 100: automatic cleaning mechanism, 101: screw shaft, 101a ... mountain, 101b ... valley, 102 ... motor, 103 ... holding member, 104 ... boss, 104a ... ... Through hole, 104b ... Screw part, 104c ... Buffer member, 105a, 105b ... Arm part, 106a, 106b ... Protrusion, 107 ... Cleaning member, 200 ... Dust-proof glass, 300 ... Spiral groove

Claims (3)

An optical scanning device comprising a housing having an exit for emitting a light beam, a dust-proof glass covering the exit, and an automatic cleaning mechanism for cleaning the surface of the dust-proof glass,
The automatic cleaning mechanism is
A spiral spiral groove is provided, and an axial length of the peak portion is longer than an axial length of the valley portion at a peak portion and a valley portion formed by the spiral groove, and is rotated by a motor. A screw shaft;
A holding member for holding a cleaning member for wiping the surface of the dust-proof glass, and having a protrusion that is slidably fitted into the spiral groove on the inner wall surface of the screw shaft being inserted;
An optical scanning device comprising:   The optical scanning device according to claim 1, wherein a guide groove extending along a moving direction of the holding member is formed in the housing, and the holding member includes a protrusion inserted into the guide groove. . An optical scanning device that emits and scans a light beam, a photosensitive member that forms an electrostatic latent image when irradiated with the light beam, and a developer that forms a toner image by developing the electrostatic latent image An image forming apparatus comprising:
An image forming apparatus comprising the optical scanning device according to claim 1 or 2 as the optical scanning device.

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