JP2012018273A - Shutter mechanism for exposure equipment and image forming apparatus - Google Patents

Abstract

A shutter mechanism for an exposure apparatus and an image forming apparatus including a rotary shutter capable of reducing a space required for opening and closing operations.
A shutter frame has a beam passage opening disposed on a path of an outgoing beam from an optical scanning device when installed in an image forming apparatus. The shutter member 14 is rotatably supported by the shutter frame 12 so as to selectively close the opening 20. The shutter member 14 includes a shaft portion 146, a shutter 142, and a connecting portion 144. The shaft portion 146 is disposed outside the both ends in the length direction of the opening of the shutter frame 12. The shutter 142 has a plate shape and is configured to be able to close the entire opening 20 of the shutter frame 12. The connecting portion 144 is provided so as to rise from the shaft portion 146 and is configured to connect the shaft portion 146 and the shutter 142.
[Selection] Figure 4

Description

  The present invention relates to an exposure apparatus shutter mechanism for selectively closing a beam exit port of an exposure apparatus and an image forming apparatus including the same.

  The electrophotographic image forming apparatus includes at least an image carrier such as a photosensitive drum and an exposure device for forming an electrostatic latent image on the surface of the image carrier. Such an image forming apparatus is often provided with an exposure apparatus shutter mechanism for selectively closing a beam emission port of the exposure apparatus. In addition, some conventional shutter mechanisms for exposure apparatuses are configured to selectively close the beam exit by rotating the shutter (see, for example, Patent Document 1).

  Here, an example of a conventional shutter mechanism for an exposure apparatus will be briefly described with reference to FIGS. 1 (A) to 1 (B). The exposure apparatus shutter mechanism 110 generally includes a shutter frame 112 provided with an opening 118 for allowing a beam to pass therethrough, and a shutter 114 swingable with respect to the shutter frame 112. The shutter 114 is configured to swing around a rotation shaft 116 disposed outside the end portion in the width direction of the opening 118, and when passing through the beam, the shutter 114 is shown in FIGS. 1 (A) and 1 (B). 1C, and the closed state shown in FIG. 1D except when the beam passes.

JP 2005-157031 A

  In the exposure apparatus shutter mechanism 110 provided with the conventional rotating shutter 114 described above, since the rotation radius of the shutter 114 inevitably increases when the width of the shutter 114 is increased, the shutter 114 is opened and closed. There is an inconvenience that the required space increases.

  For this reason, when the width of the opening 118 is increased, it is necessary to secure a wide space necessary for opening and closing the shutter 114. Therefore, the process unit including the image carrier and the exposure apparatus The interval of becomes wide. As a result, inconveniences such as being unable to save space around the process unit may occur.

  An object of the present invention is to provide a shutter mechanism for an exposure apparatus and an image forming apparatus provided with a rotary shutter capable of reducing a space required for opening and closing operations.

  The shutter mechanism for an exposure apparatus according to the present invention is configured to selectively close a beam exit port of the exposure apparatus. The exposure apparatus shutter mechanism includes a shutter frame and a shutter member.

  The shutter frame is configured to be installed in the image forming apparatus. The shutter frame has a beam passage opening disposed on the path of the outgoing beam from the exposure device when installed in the image forming apparatus.

  The shutter member is rotatably supported by the shutter frame so as to selectively close the opening. The shutter member includes a shaft portion, a shutter, and a connecting portion. The shaft portion is arranged outside both ends in the length direction of the opening portion of the shutter frame. The shutter has a plate shape and is configured to be able to close the entire opening of the shutter frame. The connecting portion is provided so as to rise from the shaft portion, and is configured to connect the shaft portion and the shutter.

  In this configuration, unlike the case where the pivot axis of rotation is arranged at the end in the width direction of the shutter, the rotation radius of the shutter does not increase even if the width direction of the shutter is increased. Specifically, since the rotation radius of the shutter is mainly determined by the height (length) of the connecting portion, the width of the shutter can be increased without increasing the rotation radius of the shutter.

  For this reason, it is possible to completely close the opening by the shutter while keeping the rotation radius of the shutter short. As a result, the space required for the shutter opening operation can be reduced, and the components around the process unit can be easily arranged.

  According to the present invention, it is possible to reduce the space required for the opening / closing operation of the rotary shutter in the shutter mechanism for the exposure apparatus.

It is a figure which shows an example of the shutter mechanism for conventional exposure apparatuses. 1 is a diagram schematically illustrating an image forming apparatus according to an embodiment of the present invention. It is a figure which shows the outline of the shutter mechanism which concerns on embodiment of this invention. It is a figure which shows the open state and obstruction | occlusion state of a shutter mechanism.

  FIG. 2 is a diagram schematically illustrating the image forming apparatus 50 according to the embodiment of the present invention. The image forming apparatus 50 forms multicolor and single color images on a predetermined sheet (recording sheet) according to image data transmitted from the outside, and includes an image forming unit 82 and a document reading unit 58. ing.

  The image forming unit 82 includes four image forming stations that respectively form black (K), cyan (C), magenta (M), and yellow (Y) color images. Each image forming station includes a developing device 91, a photosensitive drum 90, a cleaner unit 93, and a charger 92.

  The image forming unit 82 further switches the optical scanning device 88, the intermediate transfer belt unit 95, the fixing unit 74, the paper feed cassette 71, the first paper discharge tray 80, the second paper discharge tray 100, and the paper transport direction. And a plurality of flappers (not shown).

  A document placing table 54 made of transparent glass on which a document is placed is provided above the image forming unit 82, and an automatic document processing device 56 is attached to the upper side of the document placing table 54. The automatic document processing device 56 automatically conveys the document on the document table 54. Further, the automatic document processing device 56 is configured to be rotatable, and the document can be manually placed by opening the document table 54.

  The charger 92 is a charging means for uniformly charging the surface of the photosensitive drum 90 to a predetermined potential. In addition to the non-contact charger as shown in FIG. 2, a contact type such as a roller or a brush is used. A charger may be used.

  The optical scanning device 88 is configured to form an electrostatic latent image on the surface of each photosensitive drum 90 based on the input image data.

  Each developing unit 91 visualizes the electrostatic latent image formed on the corresponding photosensitive drum 90 with four color toners. The cleaner unit 93 removes and collects the toner remaining on the surface of the photosensitive drum 90 after the transfer process.

  The intermediate transfer belt unit 95 disposed above the photosensitive drum 90 includes an intermediate transfer belt 94, an intermediate transfer belt driving roller 85, an intermediate transfer belt driven roller 84, four intermediate transfer rollers 96, and an intermediate transfer belt cleaning unit. 86.

  The intermediate transfer belt driving roller 85, the intermediate transfer belt driven roller 84, and the intermediate transfer roller 96 are configured to stretch the intermediate transfer belt 94. Each intermediate transfer roller 96 is configured to transfer the toner image on the corresponding photosensitive drum 90 onto the intermediate transfer belt 94.

  The intermediate transfer belt 94 is provided so as to come into contact with the respective photosensitive drums 90, and the toner images of the respective colors formed on the photosensitive drums 90 are sequentially superimposed and transferred onto the intermediate transfer belt 94. Further, it has a function of forming a color toner image (multicolor toner image) on the intermediate transfer belt 94. The intermediate transfer belt 94 is formed in an endless shape using, for example, a film having a thickness of about 100 μm to 150 μm.

  When transferring the toner image from the photosensitive drum 90 to the intermediate transfer belt 94, a high voltage transfer bias (a polarity opposite to the toner charging polarity (-)) is applied to the intermediate transfer roller 96 in order to transfer the toner image. (+) High voltage) is applied. The intermediate transfer roller 96 is a roller whose base is a metal (for example, stainless steel) shaft having a diameter of 8 to 10 mm and whose surface is covered with a conductive elastic material (for example, EPDM, urethane foam, or the like). By this conductive elastic material, a high voltage can be uniformly applied to the intermediate transfer belt 94. In this embodiment, a roller shape is used as the transfer electrode, but a brush-shaped transfer electrode or the like can also be used.

  As described above, the electrostatic images visualized according to the respective hues on the respective photosensitive drums 90 are laminated on the intermediate transfer belt 94. As described above, the laminated image information is transferred onto the sheet by the secondary transfer roller 87 arranged at the contact position between the sheet and the intermediate transfer belt 94 described later by the rotation of the intermediate transfer belt 94.

  At this time, the intermediate transfer belt 94 and the secondary transfer roller 87 are pressed against each other at a predetermined nip, and a voltage for transferring the toner onto the sheet is applied to the secondary transfer roller 87 (toner charging polarity (−)). Is a high voltage with a reverse polarity (+). Further, in order to obtain the nip constantly, the secondary transfer roller 87 uses either the secondary transfer roller 87 or the intermediate transfer belt drive roller 85 as a hard material (metal or the like) and the other as a soft material such as an elastic roller. A material (such as an elastic rubber roller or a foaming resin roller) is used.

  Further, as described above, the toner adhered to the intermediate transfer belt 94 by contacting the photosensitive drum 90 or the toner remaining on the intermediate transfer belt 94 without being transferred onto the paper by the secondary transfer roller 87 In order to cause a color mixture of toner in the next process, the intermediate transfer belt cleaning unit 86 is set to be removed and collected. The intermediate transfer belt cleaning unit 86 includes a cleaning blade as a cleaning member that contacts the intermediate transfer belt 94, for example, and the intermediate transfer belt 94 that contacts the cleaning blade is supported by an intermediate transfer belt driven roller 84 from the back side. ing.

  The paper feed cassette 71 is a tray for storing paper (recording paper) used for image formation, and is provided below the optical scanning device 88 of the image forming unit 82. Further, paper used for image formation can also be placed in the manual paper feed cassette 78.

  The first paper discharge tray 80 is provided above the image forming unit 82, and is configured to stack printed sheets with the print side down. On the other hand, the second paper discharge tray 100 is disposed outside the casing of the image forming apparatus 50 and is configured to stack printed sheets with the print side up.

  In the image forming unit 82, the sheets in the sheet feeding cassette 71 and the manual sheet feeding cassette 78 are transferred to the first sheet discharge tray 80 or the second sheet discharge tray 100 via the secondary transfer roller 87 and the fixing unit 74. A paper conveyance path 77 for feeding is provided. In the vicinity of the sheet conveyance path 77 from the sheet feeding cassette 71 or the manual sheet feeding cassette 78 to the first sheet discharge tray 80 and the second sheet discharge tray 100, pickup rollers 73 and 75 and a plurality of conveyance rollers 62 and 64 are provided. , 66, 68, a registration roller 79, a secondary transfer roller 87, a fixing unit 74, and the like.

  The transport rollers 62, 64, 66 and 68 are small rollers for promoting and assisting the transport of paper, and a plurality of the transport rollers 62, 64, 66 and 68 are provided along the paper transport path 77. The pickup roller 73 is provided near the end of the paper feed cassette 71, picks up paper one by one from the paper feed cassette 71, and supplies it to the paper transport path 77. Similarly, the pickup roller 75 is provided near the end of the manual paper feed cassette 78, picks up paper one by one from the manual paper feed cassette 78, and supplies it to the paper transport path 77.

  The registration roller 79 temporarily holds the paper that is being conveyed through the paper conveyance path 77. The sheet has a function of conveying the sheet to the secondary transfer roller 87 at the timing when the leading edge of the toner image on the photosensitive drum 90 is aligned with the leading edge of the sheet.

  The fixing unit 74 includes a heat roller 72 and a pressure roller 76, and the heat roller 72 and the pressure roller 76 are configured to rotate with a sheet interposed therebetween. The heat roller 72 is set to have a predetermined fixing temperature by the control unit based on a signal from a temperature detector (not shown). The heat roller 72 has a function of fusing, mixing, and pressing the multi-color toner image transferred to the paper and thermally fixing the paper to the paper by thermocompression bonding the toner to the paper together with the pressure roller 76. . An external heating belt 70 for heating the heat roller 72 from the outside is provided.

  Next, the paper conveyance path will be described in detail. As described above, the image forming apparatus is provided with the paper feed cassette 71 for storing paper and the manual paper feed cassette 78 in advance. Pickup rollers 73 and 75 are arranged to feed paper from the paper feed cassettes 71 and 78, respectively, and guide the paper one by one to the conveyance path 77.

  The sheets conveyed from the sheet cassettes 71 and 78 are conveyed to the registration rollers 79 by the conveyance rollers 62 in the sheet conveyance path 77. Then, the sheet is conveyed to the secondary transfer roller 87 at a timing when the leading end of the sheet and the leading end of the image information on the intermediate transfer belt 94 are aligned, and the image information is written on the sheet. After that, the sheet passes through the fixing unit 74 so that the unfixed toner on the sheet is melted and fixed by heat. Then, the sheet passes through the conveying roller 68 disposed and then the first discharge tray 80 or the second discharge tray 100. Discharged to the top.

  The conveyance path is for single-sided printing on paper. On the other hand, at the time of double-sided printing, the trailing edge of the paper that has finished single-sided printing and passed through the fixing unit 74 as described above is held by the final transport roller 68. Thereafter, the conveyance roller 68 is rotated in the reverse direction, and the position of a flapper (not shown) is switched to guide the sheet to the return conveyance path where the conveyance rollers 66 and 64 are arranged. The sheet reaches the contact position with the intermediate transfer belt 94 through the registration roller 79 from the return conveyance path, and printing is performed on the back surface thereof. The paper is then discharged to the first paper discharge tray 80.

  In the above-described configuration, the shutter mechanism 10 that can selectively close the beam exit of the ceiling of the optical scanning device 88 is provided above the optical scanning device 88. The present invention is characterized by the structure of the shutter mechanism 10, and details thereof will be described below.

  As shown in FIGS. 3A and 3B, the shutter mechanism 10 is rotatably supported by the shutter frame 12 having an opening 20 and a shutter frame 12 so as to selectively close the opening. The shutter member 14 is provided.

  The shutter frame 12 is locked to a predetermined position of the frame in the housing of the image forming apparatus 50 via the engaging portion 126. The opening 20 of the shutter frame 12 is disposed on the path of the outgoing beam from the optical scanning device 88 when the shutter frame 12 is locked to the frame in the housing of the image forming apparatus 50. The length and width of the opening 20 of the shutter frame 12 are set so that the scanning beam emitted from the optical scanning device 88 passes completely.

  The shutter frame 12 includes a bearing portion 122 and a bearing portion 124 for supporting the shutter member 14 in a rotatable state at both ends in the length direction. The bearing portion 122 and the bearing portion 124 are disposed on both sides in the length direction of the opening 20 with the opening 20 interposed therebetween.

  On the other hand, the shutter member 14 includes a shaft portion 146, a shutter 142, and a connecting portion 144. The shaft portion 146 is disposed at both ends of the shutter member 14. The shutter 142 is configured to be able to close the entire area of the opening 20. The connecting portion 144 is provided so as to rise from the shaft portion 146 at a right angle, and is configured to connect the shaft portion 146 and the shutter 142. Here, an example in which the connecting portion 144 is configured to rise from the shaft portion 146 at a right angle has been described, but the rising angle of the connecting portion 144 is not limited to a right angle.

  In the above-described configuration, the length and the arrangement position of the shutter 142 are set such that both ends of the shutter 142 in the length direction are located outside the both ends of the opening 20 in the length direction. For this reason, the connecting portion 144 and the shaft portion 146 connected to both ends of the shutter 142 are disposed outside the both ends in the length direction of the opening 20.

Since the shutter member 14 is connected to a drive mechanism such as a solenoid arm through a link mechanism, the shutter 142 is opened and closed by appropriately controlling the drive mechanism. When the opening / closing operation of the shutter 142 is performed, the shutter 142 rotates around the pivot while maintaining a state of being opposed to the pivot while being substantially parallel to the pivot. FIG. (B) shows a state in which the shutter 142 has moved to the open position and the opening 20 of the shutter frame 12 has been opened. In this state, the scanning beam emitted from the optical scanning device 88 passes through the opening 20.

  On the other hand, FIGS. 4C and 4D show a state where the shutter 142 has moved to the closed position and the opening 20 of the shutter frame 12 has been closed. In this state, the scanning beam is prevented from leaking from the opening 20, and dust such as toner is prevented from entering the beam exit of the optical scanning device 88 through the opening 20.

  According to the above-described configuration, unlike the case where the pivot of rotation is arranged at the end of the shutter 142 in the width direction, even if the width direction of the shutter 142 is increased, the rotation radius of the shutter 142 does not increase. In the configuration according to this embodiment, since the rotation radius of the shutter 142 is mainly determined by the height (length) of the connecting portion 144, the width of the shutter 142 is increased without increasing the rotation radius of the shutter 142. It becomes possible.

  For this reason, even when the width of the opening 20 of the shutter frame 12 is increased, the rotation radius of the shutter 142 can be kept small. Therefore, the process unit including the photosensitive drum 90 and the shutter mechanism 10 are disposed close to each other. As a result, the image forming apparatus 50 can be saved in space.

  Further, in the above-described configuration, it is preferable that the shaft portion 146 (or the pivot axis of the rotation of the shutter 142 defined by the shaft portion 146) is disposed at a position corresponding to the center portion in the width direction of the opening portion 20. This is because the height (length) of the connecting portion 144 can be reduced by disposing the shaft portion 146 at a position corresponding to the central portion in the width direction of the opening 20.

  Furthermore, in the above-described configuration, it is preferable that the cross section of the shutter 142 has an arc shape. The reason is that if the shutter 142 has a circular cross section, dust can be more effectively prevented from entering the opening 20. For example, if a wall member is formed on the peripheral edge of the opening 20 in the upward direction, the combination of the wall member and the shutter 142 effectively prevents dust falling obliquely downward from entering the opening 20. It becomes possible to prevent.

  The exposure apparatus to which the shutter mechanism described above is applied is not limited to an optical scanning apparatus (laser scanner unit) having a polygon mirror. For example, the above-described shutter mechanism can be applied to an exposure apparatus that uses an LED print head.

  The above description of the embodiment is to be considered in all respects as illustrative and not restrictive. The scope of the present invention is shown not by the above embodiments but by the claims. Furthermore, the scope of the present invention is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

10-Shutter mechanism 12-Shutter frame 14-Shutter member 20-Opening portion 122, 124-Bearing portion 142-Shutter 144-Connecting portion 146-Axis

Claims (4)

An exposure apparatus shutter mechanism for selectively closing a beam exit port of an exposure apparatus,
A shutter frame that can be installed in the image forming apparatus, the shutter frame having an opening for passing a beam that is disposed on a path of an outgoing beam from the exposure apparatus when installed in the image forming apparatus;
A shutter member rotatably supported by the shutter frame so as to selectively close the opening.
With
The shutter member is
A shaft portion arranged outside both ends in the length direction of the opening,
A plate-like shutter capable of closing the entire area of the opening;
A connecting portion provided to rise from the shaft portion, the connecting portion configured to connect the shaft portion and the shutter;
A shutter mechanism for an exposure apparatus.   2. The shutter mechanism for an exposure apparatus according to claim 1, wherein the shaft portion is disposed at a position corresponding to a central portion in a width direction orthogonal to the length direction of the opening.   The shutter mechanism for an exposure apparatus according to claim 1, wherein a cross section of the shutter has an arc shape.   An image forming apparatus comprising the exposure apparatus shutter mechanism according to claim 1 between an exposure apparatus and an image carrier.

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