JP2010185993A - Optical scanner and image-forming device equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the optical characteristics of an optical scanner, which is mounted on an image-forming device, without increasing cost. <P>SOLUTION: An exposure window is provided at a position, which corresponds to a second fθ lens, on the upper face of an optical scanner 1000, and a slidable optical scanner cover 1100 is provided above the optical scanner 1000. A shutter 1410 for opening and closing the exposure window is formed in the optical scanner cover 1100. A pore 1412 is formed at the center part of the shutter 1410, and a pore 1414 is formed at the end part of the shutter 1410. When the exposure window is closed by the shutter 1410, laser beams are radiated from the pore 1412 and the pore 1414, and these laser beams are measured to measure the optical characteristics of the optical scanner. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical scanning device for performing optical writing in an electrophotographic printer or the like, and in particular, using light from an exposure window of laser light, the optical characteristics of the optical scanning device itself (characteristics due to assembly accuracy) ), And an optical scanning device capable of easily measuring optical characteristics (characteristics due to mounting accuracy) of the optical scanning device in the image forming apparatus. The present invention also relates to an image forming apparatus provided with such an optical scanning device.

  Image forming apparatuses such as laser printers, digital copying machines, and laser facsimiles include an optical scanning device (LSU: Laser Scanning Unit) for writing a latent image on a photosensitive member (electrostatic latent image carrier). Since this LSU has an optical element and is required to have extremely high dimensional accuracy and no dust, it is mounted on the main body of the image forming apparatus as an independent sealed unit. Even when the LSU itself is assembled or when the LSU is mounted on the image forming apparatus, it is necessary to adjust with high accuracy.

  For this reason, Japanese Patent Application Laid-Open No. 10-233899 (Patent Document 1) can reduce costs by providing a reference surface that serves as a reference when optically adjusting an LSU and when mounted on the image forming apparatus main body. An optical scanning device is disclosed. The optical scanning device disclosed in this publication includes a light source that generates a light beam, first optical means that gives predetermined optical characteristics to the light beam emitted from the light source, and a rotating body. The optical scanning device includes a scanning unit that rotates a rotating body in a predetermined direction and scans a light beam that has passed through the first optical unit toward a scanning target, and a light beam that has been scanned by the scanning unit. An optical system including a second optical unit that forms an image at a predetermined position of an object, a bottom portion that accommodates the optical system, and an opening provided on a side facing the bottom portion, the bottom side being an external device And a housing having a first reference surface that is used as a reference when set to an external device and a second reference surface that is used as a reference when setting the opening side to an external device.

  According to this optical scanning device, the optical system is fixed to the external device based on the first reference surface provided on the surface in contact with the external device on the bottom side, and the optical system is opened from the opening side of the housing where the optical system is exposed. The optical system is fixed to the bottom of the casing by adjustment, and the casing provided with the optical system is fixed to the external apparatus with reference to the second reference plane provided on the surface in contact with the external apparatus on the opening side. For this reason, since a reference surface serving as a reference is provided at the time of optical adjustment and when mounted on the main body, it can be assembled and mounted on the image forming apparatus with high accuracy.

JP-A-10-233899

  In recent years, with improvement in image processing performance, colorization, high image quality, and an increase in document size are required. Increasing the size of the original document leads to an increase in the size of the casing of the optical scanning device, and the increase in color and the increase in image quality have led to further improvement in the accuracy of optical characteristics. For this reason, it is becoming difficult to improve the positioning accuracy by using a part of the casing as in Patent Document 1 described above.

  On the other hand, in order to improve the assembly accuracy or positioning accuracy, using a dedicated structure or attaching a dedicated jig increases the cost of the optical scanning device itself and the cost of the image forming apparatus to which the optical scanning device is mounted. There is a possibility to make it.

  Accordingly, an object of the present invention is to provide an optical scanning device capable of improving the optical characteristics of the optical scanning device mounted on the image forming apparatus without increasing the cost, and an image forming apparatus including the optical scanning device. It is.

  An optical scanning device according to an aspect of the present invention is a light for forming an electrostatic latent image on an image carrier by scanning the image carrier with light emitted from an exposure window provided on an upper surface of a housing. A scanning device that is provided on a shielding member that shields the exposure window, transmits a part of the light emitted from the exposure window, and is provided on the upper surface of the housing and is emitted from the exposure window. One of the light shielding members that shield part of the light is provided.

  The width of the light transmitted by the light transmitting member and the width of the light shielded by the light shielding member are sufficiently high to determine the optical characteristics of the optical scanning device with respect to the length in the longitudinal direction of the image carrier. Can be configured as short.

Further, the optical scanning device is provided on the upper surface of the housing, and a shutter member that opens and closes the exposure window;
And a mechanism for sliding the shutter member. In this case, the translucent member can be configured to be provided on the shutter member.

  Furthermore, the optical scanning device can be configured to include a locking member that is provided on the top surface of the housing and that stretches the wire so as to cross the exposure window in a direction perpendicular to the longitudinal direction of the image carrier. In this case, the light shielding member can be configured as a wire rod stretched around the locking member.

  Note that the position of the light transmitting member and the light shielding member can be configured as a central portion in the longitudinal direction of the image carrier, and can also be configured as an end portion in the longitudinal direction of the image carrier. Furthermore, the positions of the light transmissive member and the light shielding member can be configured as a central portion and an end portion in the longitudinal direction of the image carrier. At this time, this end can be configured as an end on the scanning start side of the image carrier.

  An image forming apparatus according to another aspect of the present invention is an image forming apparatus including any one of the optical scanning devices described above.

  According to the optical scanning device of the present invention, a light transmissive member provided on a shielding member (shutter member) that closes the exposure window when light emission is unnecessary and opens the exposure window when light emission is necessary, or Only one part of the light (laser light) is emitted or only part of the light is shielded and emitted by any of the light shielding members (wires) stretched on the upper surface of the casing of the optical scanning device. The assembly accuracy of the optical scanning device itself is measured by measuring the emitted laser light, and the assembly accuracy of the optical scanning device to the image forming apparatus is measured by measuring the image drawn by the emitted laser light. Can be measured. For this reason, the optical characteristics of the optical scanning device mounted on the image forming apparatus can be improved without increasing the cost.

1 is a cross-sectional view illustrating an internal structure of an image forming apparatus including an optical scanning device according to a first embodiment of the present invention. It is a top view which shows the internal structure of the optical scanning device in FIG. It is a side view which shows the internal structure of the optical scanning device in FIG. It is a perspective view which shows the internal structure of the optical scanning device in FIG. 1 is a top view of an optical scanning device according to a first embodiment of the present invention. 1 is a side view of an optical scanning device according to a first embodiment of the present invention. It is a top view which shows the cover of the optical scanning device which concerns on the 1st Embodiment of this invention. It is a top view which shows the state which the shutter of the optical scanning device concerning the 1st Embodiment of this invention closed completely. It is AA sectional drawing in FIG. It is a perspective view which shows the state which the shutter opened in the optical scanning device concerning the 1st Embodiment of this invention. It is a top view of the optical scanning device concerning a 2nd embodiment of the present invention. It is a perspective view which shows the state in which the wire was provided in the optical scanning device based on the 2nd Embodiment of this invention. It is a figure which shows the example of image formation.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description and drawings, the same parts are denoted by the same reference numerals. Their functions and names are also the same. Therefore, detailed description thereof will not be repeated. In the following, the image forming apparatus according to the embodiment of the present invention will be described as a tandem full color type, but may be a full color type of another type (for example, a rotation process) or a monochrome type.
<First Embodiment>
FIG. 1 is a cross-sectional view showing an internal structure of an image forming apparatus 100 including an optical scanning device 1000 according to the first embodiment of the present invention.

  The image forming apparatus 100 forms a multicolor image or a single color image on a predetermined sheet (recording paper) in accordance with image data transmitted from the outside. In general, the image forming apparatus 100 is an image forming apparatus. 100 main body units 110 and an automatic document processing apparatus 120. The main body 110 includes an optical scanning device 1000, a developing device 2, a photosensitive drum 3, a cleaner unit 4, a charger 5, an intermediate transfer belt unit 6, a fixing unit 7, a paper feed cassette 81, a paper discharge tray 91, and the like. Configured.

  A document placing table 92 made of transparent glass on which a document is placed is provided on the upper part of the main body 110, and an automatic document processing device 120 is attached to the upper side of the document placing table 92. The automatic document processing device 120 automatically conveys the document on the document placing table 92. Further, the automatic document processing device 120 is configured to be rotatable in the direction of arrow M, and the document can be placed manually by opening the document table 92.

  Image data handled in the image forming apparatus 100 is data corresponding to a color image using each color of black (K), cyan (C), magenta (M), and yellow (Y). Accordingly, four developing devices 2, photosensitive drums 3, chargers 5, and cleaner units 4 are provided so as to form four types of latent images corresponding to the respective colors, and four of black, cyan, magenta, and yellow are provided. One image station is configured.

  The charger 5 functions to uniformly charge the surface of the photosensitive drum 3 to a predetermined potential. The optical scanning device 1000 is configured as a unit including a laser emitting unit and a reflection mirror. The optical scanning device 1000 includes a polygon mirror that scans the laser beam and optical elements such as a lens and a mirror for guiding the laser beam reflected by the polygon mirror to the photosensitive drum 3. A specific configuration of the optical scanning apparatus 1000 will be described later.

  The optical scanning device 1000 has a function of forming an electrostatic latent image on the surface of the charged photosensitive drum 3 according to the image data by exposing the photosensitive drum 3 according to the input image data. The developing device 2 visualizes the electrostatic latent images formed on the respective photosensitive drums 3 with toners of four colors (Y, M, C, K). The cleaner unit 4 removes and collects toner remaining on the surface of the photosensitive drum 3 after development and image transfer.

  The intermediate transfer belt unit 6 disposed above the photosensitive drum 3 includes an intermediate transfer belt 61, an intermediate transfer belt driving roller 62, an intermediate transfer belt driven roller 63, an intermediate transfer roller 64, and an intermediate transfer belt cleaning unit 65. I have. Four intermediate transfer rollers 64 are provided corresponding to the respective colors Y, M, C, and K. The intermediate transfer belt driving roller 62, the intermediate transfer belt driven roller 63, and the intermediate transfer roller 64 are driven to rotate while the intermediate transfer belt 61 is stretched. The intermediate transfer roller 64 provides a transfer bias for transferring the toner image on the photosensitive drum 3 onto the intermediate transfer belt 61.

  The intermediate transfer belt 61 is provided so as to be in contact with the four photosensitive drums 3, and each color toner image formed on the photosensitive drum 3 is sequentially superimposed and transferred onto the intermediate transfer belt 61. Thus, a color toner image (multicolor toner image) is formed on the intermediate transfer belt 61. The intermediate transfer belt 61 is formed in an endless shape using, for example, a film having a thickness of about 100 μm to 150 μm.

  The toner image is transferred from the photosensitive drum 3 to the intermediate transfer belt 61 by an intermediate transfer roller 64 that is in contact with the back side of the intermediate transfer belt 61. A high-voltage transfer bias (a high voltage having a polarity (+) opposite to the toner charging polarity (−)) is applied to the intermediate transfer roller 64 in order to transfer the toner image. The intermediate transfer roller 64 is a roller whose base is a metal (for example, stainless steel) shaft having a diameter of 8 mm to 10 mm and whose surface is covered with a conductive elastic material (for example, ethylene-propylene-diene rubber, urethane foam, or the like). With this conductive elastic material, a high voltage can be uniformly applied to the intermediate transfer belt 61. In this embodiment, a roller-shaped electrode is used as the transfer electrode, but a brush-shaped electrode or the like can be used in addition to that.

  As described above, the electrostatic latent images visualized according to the respective colors on the respective photosensitive drums 3 are stacked on the intermediate transfer belt 61. In this way, the laminated image information is transferred onto the recording sheet by the transfer roller 10 disposed at the contact position between the recording sheet and the intermediate transfer belt 61 described later by the rotation of the intermediate transfer belt 61.

  At this time, the intermediate transfer belt 61 and the transfer roller 10 are pressed against each other at a predetermined nip, and a voltage for transferring the toner to the recording paper is applied to the transfer roller 10 (opposite to the toner charging polarity (−)). Polarity (+) high voltage). Further, in order to obtain the above nip constantly, the transfer roller 10 uses either the transfer roller 10 or the intermediate transfer belt drive roller 62 as a hard material (metal or the like) and the other as a soft material such as an elastic roller (an elastic rubber roller). Or a foamed resin roller or the like).

  Further, as described above, the toner adhering to the intermediate transfer belt 61 by contacting the photosensitive drum 3 or the toner remaining on the intermediate transfer belt 61 without being transferred onto the recording paper by the transfer roller 10 is used in the next step. Therefore, the intermediate transfer belt cleaning unit 65 is configured to remove and collect the toner. The intermediate transfer belt cleaning unit 65 is provided with, for example, a cleaning blade as a cleaning member that comes into contact with the intermediate transfer belt 61. The intermediate transfer belt 61 that comes into contact with the cleaning blade is driven by an intermediate transfer belt driven roller 63 from the back side. It is supported.

  The paper feed cassette 81 is a tray for storing sheets (recording paper) used for image formation, and is provided below the optical scanning device 1000 of the main body 110. A sheet used for image formation can also be placed on the manual paper feed cassette 82. A paper discharge tray 91 provided above the main body 110 is a tray for collecting printed sheets face down.

  The main body 110 is provided with a substantially vertical sheet conveyance path S for sending the sheets of the sheet feeding cassette 81 and the manual sheet feeding cassette 82 to the sheet discharge tray 91 via the transfer roller 10 and the fixing unit 7. It has been. In the vicinity of the paper transport path S from the paper feed cassette 81 or the manual paper feed cassette 82 to the paper discharge tray 91, there are a pickup roller 11a, a pickup roller 11b, a plurality of transport rollers 12a to 12d, a registration roller 13, and a transfer roller. 10, a fixing unit 7 and the like are arranged.

  The conveyance rollers 12a to 12d are small rollers for promoting and assisting conveyance of the sheet, and a plurality of the conveyance rollers 12a to 12d are provided along the sheet conveyance path S. The pickup roller 11 a is provided near the end of the paper feed cassette 81, picks up sheets one by one from the paper feed cassette 81, and supplies them to the paper transport path S. Similarly, the pickup roller 11b is provided near the end of the manual paper feed cassette 82, picks up one sheet at a time from the manual paper feed cassette 82, and supplies it to the paper transport path S.

  The registration roller 13 temporarily holds the sheet being conveyed on the sheet conveyance path S. The sheet has a function of conveying the sheet to the transfer roller 10 at the timing when the leading edge of the toner image on the photosensitive drum 3 and the leading edge of the sheet are aligned.

  The fixing unit 7 includes a heat roller 71 and a pressure roller 72, and the heat roller 71 and the pressure roller 72 rotate with the sheet interposed therebetween. The heat roller 71 is set to have a predetermined fixing temperature by a control unit based on a signal from a temperature detector (not shown), and the pressure roller 72 and the toner are thermocompression-bonded to the sheet. The multicolor toner image transferred onto the sheet is melted, mixed and pressed, and thermally fixed to the sheet.

  Next, the sheet conveyance path will be described in detail. As described above, the image forming apparatus 100 is provided with the paper feed cassette 81 and the manual paper feed cassette 82 for storing sheets in advance. In order to feed sheets from these sheet feeding cassettes 81 or manual sheet feeding cassettes 82, pickup rollers 11a or pickup rollers 11b are arranged to guide the sheets one by one to the sheet conveyance path S.

  The sheet conveyed from the sheet feeding cassette 81 or the manual sheet feeding cassette 82 is conveyed to the registration roller 13 by the conveying roller 12a in the sheet conveying path S, and aligns the leading edge of the sheet with the leading edge of the image information on the intermediate transfer belt 61. It is conveyed to the transfer roller 10 at a timing, and image information is written on the sheet. Thereafter, the sheet passes through the fixing unit 7 so that the unfixed toner on the sheet is melted and fixed by heat, and is discharged onto the sheet discharge tray 91 through the conveyance roller 12b disposed thereafter.

  The above-mentioned conveyance path is for a single-sided printing request for a sheet. On the other hand, when a double-sided printing request is made, the trailing edge of the sheet that has finished single-sided printing and has passed through the fixing unit 7 as described above. When the sheet is held by the final conveying roller 12b, the conveying roller 12b rotates backward to guide the sheet to the conveying rollers 12c and 12d. Thereafter, after printing is performed on the back surface of the sheet through the registration roller 13, the sheet is discharged to the discharge tray 91.

  Next, the internal structure of the optical scanning apparatus 1000 will be described in detail with reference to FIG. 2, FIG. 3, and FIG. 2 is a top view showing the internal structure of the optical scanning apparatus 1000 in FIG. 1, FIG. 3 is a side view showing the internal structure, and FIG. 4 is a perspective view showing the internal structure.

  In the optical scanning apparatus 1000 according to the present embodiment, each laser diode 1020 corresponding to each color of yellow (Y), magenta (M), cyan (C), and black (K) housed in a housing 1010 is provided. The collimating lens 1030 to which the laser light from each laser diode 1020 is incident, the mirror group 1035 for reflecting the laser light emitted from the collimating lens 1030, and the cylindrical to which the laser light reflected by the mirror group 1035 is incident. The lens 1040, the reflection mirror 1050 that reflects the laser light emitted from the cylindrical lens 1040, the polygon mirror (rotating polygonal mirror) 1060 that reflects the laser light reflected by the reflection mirror 1050, and the polygon mirror 1060 are reflected. Refract laser light Reflected by the 1fθ lens 1070, a plurality of exit folding mirrors 1090, 1091, 1092, 1093, 1094, 1095, 1096 that individually reflect the laser beams corresponding to the respective colors that have passed through the first fθ lens 1070, and the exit folding mirrors. Four second fθ lenses 1080, 1082, 1084, and 1086 that individually refract the laser light.

  The polygon mirror 1060 has a regular polygonal column shape, is driven to rotate at high speed, and repeatedly scans in the main scanning direction X while reflecting the laser beam by the mirror on each peripheral surface. The first fθ lens 1070, the exit folding mirrors 1090, 1091, 1092, 1093, 1094, 1095, and 1096 and the second fθ lenses 1080, 1082, 1084, and 1086 reflect the respective laser beams that are repeatedly scanned in the main scanning direction X. In order to be refracted, it is formed in a rod shape that is long in the main scanning direction X and short in the sub-scanning direction Y orthogonal to the main scanning direction X, and both ends thereof are supported.

  Laser light emitted from the laser diode 1020 corresponding to black (K) is transmitted through the collimator lens 1030, reflected by the mirror group 1035 and the reflection mirror 1050, reflected by the polygon mirror 1060, and scanned in the main scanning direction X. Further, the light passes through the first fθ lens 1086, is reflected by the output folding mirror 1096, passes through the second fθ lens 1086, and enters the photosensitive drum 3 corresponding to black.

  Laser light emitted from the laser diode 1020 corresponding to cyan (C) is transmitted through the collimator lens 1030, reflected by the mirror group 1035 and the reflection mirror 1050, reflected by the polygon mirror 1060, and scanned in the main scanning direction X. Then, the light passes through the first fθ lens 1086, is reflected by the output folding mirrors 1094 and 1095, passes through the second fθ lens 1084, and enters the photosensitive drum 3 corresponding to cyan.

  Laser light emitted from the laser diode 1020 corresponding to magenta (M) is transmitted through the collimator lens 1030, reflected by the mirror group 1035 and the reflection mirror 1050, reflected by the polygon mirror 1060, and scanned in the main scanning direction X. Further, the light passes through the first fθ lens 1086, is reflected by the output folding mirrors 1092 and 1093, passes through the second fθ lens 1082, and enters the photosensitive drum 3 corresponding to magenta.

  Laser light emitted from the laser diode 1020 corresponding to yellow (Y) is transmitted through the collimator lens 1030, reflected by the mirror group 1035 and the reflection mirror 1050, reflected by the polygon mirror 1060, and scanned in the main scanning direction X. Then, the light passes through the first fθ lens 1086, is reflected by the output folding mirrors 1090 and 1091, passes through the second fθ lens 1080, and enters the photosensitive drum 3 corresponding to yellow.

  As described above, each photosensitive drum 3 is rotationally driven, and laser beams corresponding to the respective colors that are repeatedly scanned in the main scanning direction X are irradiated to each surface of each photosensitive drum 3. An electrostatic latent image corresponding to each color is formed. When the photosensitive drum 3 is driven to rotate, laser light is irradiated in the sub-scanning direction Y, and an electrostatic latent image corresponding to each color, which is a two-dimensional image in the main scanning direction X, is displayed on the photosensitive drum 3. It can be formed on the surface. The electrostatic latent image formed on the surface of each photoconductor drum 3 is developed to become a toner image, and these toner images are transferred onto the recording paper via the intermediate transfer belt 61, and are printed on the recording paper. Toner image.

  Next, the external structure of the optical scanning apparatus 1000 according to the present embodiment will be described. FIG. 5 is a top view showing the external appearance of the optical scanning device 1000, and FIG. 6 is a side view showing the external appearance of the optical scanning device 1000. As shown in FIGS. 5 and 6, the optical scanning apparatus 1000 has a substantially rectangular parallelepiped shape whose dimension in the height direction is smaller than the width and length, and is made of, for example, an injection molded resin. . A substantially rectangular parallelepiped upper surface forming the optical scanning device 1000 is an upper surface portion 1101, and an optical scanning device cover 1100 is provided above the upper surface portion 1101 so as to be slidable with respect to the optical scanning device 1000. FIG. 7 shows a top view of the optical scanning apparatus 1000 with the optical scanning apparatus cover 1100 removed (the upper surface portion 1101 is exposed on the entire upper surface).

  As shown in FIG. 7, the upper surface portion 1101 of the optical scanning device 1000 has exposure windows 1102W, 1104W, 1106W, 1108W extending from the A side to the B side, and an end on the A side on the exposure window 1102W side. A rotating cam plate 1300 to which the rotating cam 1200 is attached, a slide protrusion 1310 to which the optical scanning device cover 1100 is attached between the exposure window 1102W and the exposure window 1104W, and the exposure window 1106W and the exposure. A slide protrusion 1320 is provided between the window 1108W and the optical scanning device cover 1100. The slide protrusion 1310 and the slide protrusion 1320 have a substantially cylindrical shape, and a hole for fitting the fastener 1102 and the fastener 1106 is provided on the upper surface thereof.

  The positions of the exposure windows 1102W, 1104W, 1106W, and 1108W on the upper surface portion 1101 of the optical scanning apparatus 1000 are as follows. An exposure window 1102W from which laser light corresponding to black is emitted at a position corresponding to the second fθ lens 1086, and an exposure window 1104W from which laser light corresponding to cyan is emitted from a position corresponding to the second fθ lens 1084 are second fθ. An exposure window 1106W for emitting laser light corresponding to magenta is provided at a position corresponding to the lens 1082, and an exposure window 1108W for emitting laser light corresponding to yellow is provided at a position corresponding to the second fθ lens 1080. Yes. These exposure windows 1102W, 1104W, 1106W, 1108W are fitted with glass or the like that transmits laser light.

  Further, a hole portion around which the rotation center of the rotation cam 1200 is pivotally provided is provided at the approximate center of the rotation cam plate 1300 provided on the upper surface portion 1101 of the optical scanning apparatus 1000. A hole into which a later-described fastener 1102 and fastener 1106 are fitted is provided at substantially the center of the slide protrusion 1310 and the slide protrusion 1320.

  Returning to FIG. 5 and FIG. 6, the optical scanning apparatus 1000 will be described. The optical scanning device 1000 includes an optical scanning device cover 1100 that can slide above the upper surface portion 1101 to prevent dust. The length of the optical scanning device cover 1100 in the Y direction is shorter than the length of the optical scanning device 1000. More specifically, it is as short as the length from the end of the upper surface portion 1101 to the exposure window 1108W.

  Exposure windows 1102W, 1104W, 1106W, and 1108W formed on the upper surface portion 1101 of the optical scanning apparatus 1000 are closed by shutters 1102S, 1104S, 1106S, and 1108S that are opened and closed in conjunction with the operation of the rotating cam 1200. The opening direction and the closing direction of these shutters 1102S, 1104S, 1106S, 1108S are indicated by arrows in FIGS. These shutters 1102 </ b> S, 1104 </ b> S, 1106 </ b> S, and 1108 </ b> S are formed by a part of the optical scanning device cover 1100, and are formed integrally with the optical scanning device cover 1100. That is, when the optical scanning device cover 1100 slides in the “closed” direction indicated by the arrow in FIG. 5 or FIG. 6, the exposure window 1102W is closed by the shutter 1102S formed by a part of the optical scanning device cover 1100, and the exposure window 1104W. Is closed by a shutter 1104S formed by a part of the optical scanning device cover 1100, the exposure window 1106W is closed by a shutter 1106S formed by a part of the optical scanning device cover 1100, and the exposure window 1108W is closed by the optical scanning device cover 1100. It is closed by a shutter 1108S formed by a part of. When the optical scanning device cover 1100 slides in the “open” direction indicated by the arrow in FIG. 5 or FIG. 6, the exposure window closed by each shutter is opened.

  The optical scanning device cover 1100 is provided with a long hole portion 1104 and a long hole portion 1108. The substantially cylindrical slide protrusion 1310 and slide protrusion 1320 provided on the upper surface portion 1101 of the optical scanning device 1000 are inserted into the long hole portion 1104 and the long hole portion 1108, respectively. A fastener 1102 and a fastener 1106 having a diameter larger than the short diameter of the long hole portion are fitted into holes on the upper surfaces of the slide protrusion 1310 and the slide protrusion 1320, respectively. Therefore, the upper surface portion 1101 of the optical scanning device 1000 can be slid without removing the optical scanning device cover 1100.

  A plurality of guide pins 1120 and 1122 are provided as positioning jigs when the optical scanning apparatus 1000 is mounted on the image forming apparatus 100. Since the upper surface portion 1101 and the optical scanning device cover 1100 (shutters 1102S, 1104S, 1106S, 1108S) of the optical scanning device 1000 do not affect the irradiation accuracy and beam diameter of the direct laser beam, both ABS (acrylonitrile, butadiene, styrene) are used. A generally inexpensive material having a relatively large thermal expansion such as a polymerized synthetic resin can also be used.

  As shown in FIG. 6, in a state where the optical scanning apparatus 1000 is mounted on the image forming apparatus 100, the laser light scanned by the polygon mirror 1060 and condensed by the exit folding mirror and the second fθ lens is exposed to the exposure window 1102W ( Black), exposure window 1104W (cyan), exposure window 1106W (magenta), and exposure window 1108W (yellow) are irradiated toward each photosensitive drum 3. In such an image forming apparatus 100, around each photosensitive drum 3, an intermediate transfer belt 61, which is a toner image of the developing device 2, the cleaner unit 4, the charger 5, and the photosensitive drum 3, is the next transfer material. An intermediate transfer roller 64 and the like for transferring to the image are arranged. When maintenance or replacement work is performed on the developing device 2 or the photosensitive drum 3, toner or dust may fall on the exposure windows 1102W, 1104W, 1106W, and 1108W located below them. The exposure windows 1102W, 1104W, 1106W, and 1108W are preferably closed by the shutters 1102S, 1104S, 1106S, and 1108S described above. In addition, since the laser light irradiated on the photosensitive drum 3 is condensed to 100 microns or less, it is reflected on the photosensitive drum 3 or other members when the polygon mirror 1060 is stopped and scanning is not performed. Therefore, there is a demand for a mechanism that does not leak out the light, and a method of shielding the laser light by the shutters 1102S, 1104S, 1106S, and 1108S is extremely effective.

  FIG. 8 is an enlarged view of the exposure window side corresponding to black in FIG. 5 in a state in which the shutter 1102S (hereinafter, shutter 1102S may be referred to as the shutter 1410) is closed and the exposure window 1102W is completely closed. A top view is shown. As described above, the rotating cam 1200 is attached to the rotating cam plate 1300 provided on the upper surface portion 1101 of the optical scanning apparatus 1000.

  The shutter 1410 is a flat plate member configured as a part of the optical scanning device cover 1100, and is configured of a non-transparent resin (preferably a black resin) that extends to cover the entire width of the exposure window 1102W. . The shutter 1410 is provided with a columnar protrusion 1420 that slidably engages with a long hole-shaped link 1230 of the rotating cam 1200. The width of the link portion 1230 (the vertical dimension in FIG. 8) is slightly larger than the diameter of the protruding portion 1420, and the diameter of the round hole (semicircular hole) at both ends of the link portion 1230 is the same as that of the protruding portion 1420. Slightly larger than the diameter. For this reason, since the projection part 1420 can move the link part 1230 slidably, and can rotate in the position of the semicircle hole of either end of the link part 1230, the projection part 1420 moves or rotates. Thus, the inclination of the shutter 1410 is changed, and the shutter 1410 can be opened and closed.

  The rotary cam 1200 is a flat plate member having a substantially L-shape, and includes a rotary shaft 1220 that is pivotally supported in a hole of the rotary cam plate 1300, a locking portion 1210 for rotating the rotary cam 1200, and a long length. And a link portion 1230 having a hole shape. As described above, the column-shaped protrusion 1420 fixed to the upper surface of the shutter 1410 is slidably and rotatably held on the link 1230. For example, a waste toner tank comes into contact with the locking portion 1210 and the rotary cam 1200 rotates to open the shutter 1410 in the closed state.

  Other shutters 1104S, 1106S, and 1108S are also formed as part of the optical scanning device cover 1100 in the same manner as the shutter 1410, and thus move in the same manner as the shutter 1410. When the rotating cam 1200 is rotated in the direction indicated by the arrow R (1) in FIG. 8, the shutter is opened, and when the rotating cam 1200 is rotated in the direction indicated by the arrow R (2), the shutter is closed.

  The optical scanning apparatus 1000 according to the present embodiment is characterized in that a part of the shutter is provided with a pore that transmits laser light. As shown in FIG. 8, the shutter 1102S (1410) that opens and closes the exposure window 1102W is provided with a pore 1412 at the center in the main scanning direction X and a pore 1414 on the A side. The pores 1412 and 1414 are slits having a width of about 0.5 to 1 mm. The width of the pores is sufficiently shorter than the length of the photosensitive drum 3 in the longitudinal direction (main scanning direction X). By measuring the laser light transmitted through this width, an optical scanning device will be described later. 1000 optical properties can be determined.

  FIG. 9 is a cross-sectional view taken along the line AA in FIG. As shown in FIG. 9, a shutter 1102S (1410) that opens and closes an exposure window 1102W has a pore 1412, and a light transmitting member 1416 made of glass, polycarbonate, or the like is attached below the aperture 1412. For this reason, when the optical scanning apparatus 1000 is operated with the exposure window 1102W closed by the shutter (when the entire surface is exposed and scanned), the laser beam is transmitted through the pores 1412 as shown by the arrows in FIG. The drum 3 is irradiated.

  The pore 1414 shown in FIG. 8 has the same configuration as the pore 1412 shown in FIG. Furthermore, as shown in FIG. 10, the shutters 1104S, 1106S, and 1108S that open and close the other exposure windows 1104W, 1106W, and 1108W are also provided with two pores, and light transmission is provided below these pores. Each member is attached.

  The positions of these pores are determined from the following viewpoints. The optical scanning apparatus 1000 and the image forming apparatus 100 are positioned by a plurality of guide pins 1120 and 1122, and the optical scanning apparatus 1000 is attached to the image forming apparatus 100. Positioning for main scanning and sub-scanning for each color can be realized by setting the transmission timing of image data. From the viewpoint of ensuring the maximum optical performance, the central portion in the scanning direction is an fθ lens or the like. It is preferable to adjust the central portion. For this reason, the positions of the pores are determined so that this adjustment is easy.

  The operation of the image forming apparatus 100 equipped with the optical scanning apparatus 1000 having the above structure will be described.

  The rotary cam 1200 of the optical scanning device 1000 is rotated in the direction of arrow R (2), and the exposure window is closed with a shutter. The rotating cam 1200 at this time is in the state shown in FIG. Although the exposure window is closed by the shutter, the shutter is provided with pores through which laser light is transmitted. For this reason, by exposing or printing with the exposure window closed by the shutter in this way, only the portion composed of the pores and the translucent member is exposed or printed, for example, on a white sheet as a whole. The pores are printed as black streaks.

  The optical characteristics (exposure position, magnification, bow, inclination) of the optical scanning apparatus 1000 can be measured by measuring the absolute position and interval of the black streaks on the print sheet. Before the optical scanning apparatus 1000 is incorporated into the image forming apparatus 100, the assembly accuracy of the optical scanning apparatus 1000 alone can be measured by measuring the beam diameter and linearity, and the optical scanning apparatus 1000 is assembled into the image forming apparatus 100. Thereafter, the amount of deviation of the position of the optical scanning device 1000 in the incorporated image forming apparatus 100 can be measured by measuring the black streaks of the printed sheet. Further, the position of the pores and the interval between the pores (the position and interval of the black streaks in the sheet) are repeatedly measured every predetermined time, and the data is accumulated to determine the positional deviation over time. be able to.

As described above, in the optical scanning device according to the present embodiment and the image forming apparatus provided with the optical scanning device, when the laser beam emission is unnecessary, the exposure window is closed and the laser beam emission is necessary. In the shutter that opens the exposure window, a hole through which laser light is transmitted is provided, and the assembly accuracy of the optical scanning device itself is measured by measuring the beam diameter and linearity of the laser light emitted from the hole. In addition, by measuring an image drawn by laser light emitted from the pores, the assembly accuracy of the optical scanning device to the image forming apparatus can be measured. For this reason, the optical characteristics of the optical scanning device mounted on the image forming apparatus can be improved without increasing the cost.
<Second Embodiment>
Hereinafter, a second embodiment of the present invention will be described.

  The optical scanning device 2000 according to the present embodiment does not need to include a shutter, and a light shielding member (wire, thread, etc.) is stretched on a hook provided on the upper surface (exposure window side) of the optical scanning device 1000 on the sheet. Printing is performed, and the optical characteristics of the optical scanning device mounted on the image forming apparatus are measured based on the printed content.

  FIG. 11 shows a top view of the optical scanning device 2000 according to the present embodiment. As shown in FIG. 11, the optical scanning device 2000 further includes center hooks 2300 and 2302 and index hooks 2200 and 2202 in addition to the configuration of the optical scanning device 1000 shown in FIG. As described above, the shutter in the optical scanning device 2000 has an arbitrary configuration.

  When measuring the optical characteristics of the optical scanning device 2000, as shown in FIGS. 11 and 12, a wire 2204 as a light shielding member is stretched by an index hook 2200 and an index hook 2202, and the wire 2304 is connected to the center 2304. The hook 2300 and the center hook 2302 are stretched. Since this wire is only locked to the hook, it can be removed.

  The wire 2204 and the wire 2304 are sufficiently short with respect to the length in the longitudinal direction (main scanning direction X) of the photosensitive drum 3 for the same reason as the above-described pores, and the laser light socialized by this wire is used. By measuring, the optical characteristics of the optical scanning device 1000 can be determined.

  When an image is formed with such a wire stretched, an image as shown in FIG. 13 is formed on the sheet. As shown in FIG. 13, the stretched wire portion appears as white streaks in the image formed on the sheet. The image shown in FIG. 13 is an example, and the present invention is not limited to this.

  By measuring the absolute position and interval of white streaks on the print sheet, the optical characteristics (exposure position, magnification, bow, tilt) of the optical scanning device 2000 can be measured. By measuring the black streaks on the printed sheet, it is possible to measure the amount of positional deviation of the optical scanning device 2000 in the incorporated image forming apparatus 100. Also, the white streak position and white streak interval (white streak position and spacing on the print sheet) are repeatedly measured at regular intervals, and these data are accumulated to determine position shifts over time. can do.

  As described above, in the optical scanning device according to the present embodiment and the image forming apparatus including the optical scanning device, even when the shutter for closing and opening the exposure window is not provided, The assembly accuracy of the optical scanning device can be measured. For this reason, the optical characteristics of the optical scanning device mounted on the image forming apparatus can be improved without increasing the cost.

  In the above-described embodiment, two pores or wires are provided in the main scanning direction X. However, if the reference of the conveyed sheet is the center, the center side is preferable, and the reference of the conveyed sheet is The writing position (at least one side that is not the central side) is preferable if it is the writing position (one side that is not the center). When the interval is not measured in this way, either one may be used. Furthermore, when it is not the center side, it is preferable that the writing start side is close to the writing position (because it is immediately after writing), so that an error accompanying writing can be suppressed, and the positional deviation can be measured more accurately. be able to.

  Also, the four pores according to the first embodiment and the four members of the two wires according to the second embodiment may be appropriately combined.

  The embodiment disclosed herein is merely an example, and the present invention is not limited to the above-described embodiment. The scope of the present invention is indicated by each claim in the claims after taking into account the description of the detailed description of the invention, and all modifications within the meaning and scope equivalent to the wording described therein are intended. Including.

DESCRIPTION OF SYMBOLS 100 Image forming apparatus 1000 Optical scanning apparatus 1010 Case 1020 Laser diode 1030 Collimating lens 1040 Cylindrical lens 1050 Reflection mirror 1060 Polygon mirror 1100 Optical scanning apparatus cover 1102W, 1104W, 1106W, 1108W Exposure window 1200 Rotating cam 1230 Link part 1300 Rotating cam plate 1102S, 1104S, 1106S, 1108S, 1410 Shutter 1420 Protrusion

Claims (9)

An optical scanning device for scanning an image carrier with light emitted from an exposure window provided on an upper surface of a housing to form an electrostatic latent image on the image carrier,
A light-transmitting member that is provided on a shielding member that shields the exposure window and transmits a part of the light emitted from the exposure window; and a light-transmitting member that is provided on the upper surface of the housing and that is emitted from the exposure window. An optical scanning device including any one of light shielding members for shielding a part of the light.   The width of the light transmitted by the light transmitting member and the width of the light blocked by the light shielding member are sufficient to determine the optical characteristics of the optical scanning device with respect to the length in the longitudinal direction of the image carrier. The optical scanning device according to claim 1, which is short. The optical scanning device includes:
A shutter member provided on the upper surface of the housing for opening and closing the exposure window;
A mechanism for sliding the shutter member,
The optical scanning device according to claim 1, wherein the translucent member is provided on the shutter member. The optical scanning device includes:
A locking member that is provided on the upper surface of the housing and stretches a wire so as to cross the exposure window in a direction perpendicular to the longitudinal direction of the image carrier;
The optical scanning device according to claim 1, wherein the light shielding member is a wire stretched on the locking member.   3. The optical scanning device according to claim 1, wherein the light transmitting member and the light shielding member are positioned at a central portion in a longitudinal direction of the image carrier.   3. The optical scanning device according to claim 1, wherein the light transmitting member and the light shielding member are positioned at end portions in a longitudinal direction of the image carrier. 4.   3. The optical scanning device according to claim 1, wherein positions of the light transmitting member and the light shielding member are a center portion and an end portion in a longitudinal direction of the image carrier. 4.   The optical scanning device according to claim 6, wherein the end portion is an end portion on a scanning start side of the image carrier.   An image forming apparatus comprising the optical scanning device according to claim 1.

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