JP2007286196A - Image forming apparatus and processing cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus of positively forming an image carrier. <P>SOLUTION: The image forming apparatus 10 has: an image carrier 36; a fixing device 32 for fixing toner images transferred from the image carrier 36 on sheets; and a duct 66 guiding the air supplied from the blower 64 to the image carrier 36, in order to prevent temperature increase of the image carrier 36 by heat from the fixing device 32 or the like. A protection cover 78 for protecting the image carrier 36 composes a part of the duct. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a printer, a copying machine, and a facsimile, and a process cartridge used therefor.

  In general, an xerographic image forming apparatus includes a fixing device that fixes a toner image transferred from an image carrier onto a sheet. Since this fixing device fixes the toner image on the sheet by pressure and heat, a blower is provided to discharge heat generated from the fixing device outside the apparatus so that other devices are not affected by the heat. I have to.

  As a conventional example of this type, there is known one in which an exhaust passage is formed by using a shutter that covers and protects an image carrier so that heat generated from the fixing device is efficiently discharged out of the apparatus ( Patent Document 1).

JP 11-249368 A

  However, in the above conventional example, in order to efficiently discharge heat, the shutter is prevented from flowing into the image carrier side. For this reason, since the image carrier cannot be cooled positively, failures caused by the image carrier weak at high temperatures are likely to occur. Further, no countermeasure is taken against overheating of the image carrier due to heat generated from a different path from the fixing device as in the double-sided printing device. Problems caused by these include offset (a phenomenon in which melted or softened toner adheres to the image carrier and this toner is transferred to the next sheet) and blade squeal (melting occurs when a blade type cleaner is used). There is also a possibility that the blade vibrates due to the softened toner and a phenomenon in which abnormal noise is generated).

  An object of the present invention is to provide an image forming apparatus capable of actively cooling an image carrier.

  The first feature of the present invention is that an image carrier, a fixing device for fixing a toner image transferred from the image carrier to a sheet, a blowing unit, and air is sucked or discharged by the blowing unit. And an image forming apparatus having duct means having a mouth facing the image carrier. Therefore, since the duct unit is configured so that the air intake or discharge port is directed toward the image carrier by the blower unit, the image carrier can be cooled by the air sucked or discharged from the blower unit.

  Preferably, the duct means is formed so that a width in a direction perpendicular to the axial direction of the image carrier gradually becomes narrower toward an inlet for sucking or discharging the air. Since the flow rate of air sucked or discharged toward the image carrier can be increased, the cooling efficiency of the image carrier can be increased.

  Preferably, the apparatus further includes a protective cover that is movably supported, and the protective cover moves to a position that protects the image carrier and a position that forms part of the duct means. . Since the duct means can be configured using the protective cover, the number of parts can be reduced and the structure can be simplified.

  The second feature of the present invention is that the image forming apparatus main body, a process cartridge that is detachably attached to the image forming apparatus main body and has an image carrier, and is housed in the image forming apparatus main body. A fixing device for fixing the toner image transferred from the image carrier to a sheet, a blowing unit, and a duct unit provided with a port for sucking or discharging air by the blowing unit toward the image carrier. An image forming apparatus having the same.

  Preferably, the main body of the image forming apparatus has an open / close cover for attaching and detaching the process cartridge, and the process cartridge further includes a protective cover that is movably supported. It moves in conjunction with the opening / closing cover to a position for protecting the carrier and a position constituting a part of the duct means.

  Preferably, the process cartridge includes a process cartridge main body, and the duct unit includes the image forming apparatus main body, the process cartridge main body, and a protective cover.

  Preferably, the protective cover is configured to come into contact with the main body of the image forming apparatus when it is in a position constituting a part of the duct unit. Since the other end of the protective cover is brought into contact with the image forming apparatus main body, it is possible to prevent air from leaking from this portion.

  The third feature of the present invention is that the image forming apparatus main body, the image carrier accommodated in the image forming apparatus main body, and the image bearing member accommodated in the image forming apparatus main body are transferred from the image carrier. A fixing device for fixing the toner image on the sheet, a blowing unit, a duct unit provided with a discharge port for discharging air by the blowing unit toward the image carrier, and a protective cover supported movably. The protective cover is moved to a position that protects the image carrier and a position that forms part of the duct means, and when the protective cover is in a position that forms part of the duct means, The image forming apparatus is configured to be in contact with an outside of a connection portion formed in the image forming apparatus main body. Therefore, when the air is discharged toward the image carrier, the protective cover comes into contact with the outside of the connection portion, so that air leakage at the connection portion can be prevented.

  The fourth feature of the present invention is that the image forming apparatus main body, the image carrier accommodated in the image forming apparatus main body, the image forming apparatus main body, and the image forming apparatus main body are transferred from the image carrier. A fixing device for fixing the toner image on the sheet, a blowing unit, a duct unit provided with an air inlet toward the image carrier by the blowing unit, and a protective cover supported movably. The protective cover moves to a position that protects the image carrier and a position that forms part of the duct means, and when the protective cover is in a position that forms part of the duct means, the image The image forming apparatus is configured to be in contact with an inner side of a connection portion formed in the forming apparatus main body. Therefore, when air is inhaled from the image carrier, the protective cover comes into contact with the inside of the connection portion, so that air leakage at the connection portion can be prevented.

  According to a fifth aspect of the present invention, there is provided a process cartridge that is detachably attached to an image forming apparatus main body in which a fixing device is accommodated, and the process cartridge main body and an image carrier provided in the process cartridge main body. And a protective cover movably provided with respect to the process cartridge main body. The protective cover moves to a position for protecting the image carrier and a position constituting a part of the duct means. When in a position constituting a part of the duct means, the front end of the protective cover is in the process cartridge constituting a part of the mouth opened toward the image carrier.

  Preferably, the duct means includes the process cartridge main body and a protective cover.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an image forming apparatus 10 according to a first embodiment of the present invention. The image forming apparatus 10 includes an image forming apparatus main body 12, an image forming unit 14 is mounted in the image forming apparatus main body 12, a discharge unit 16 is provided on the upper portion of the image forming apparatus main body 12, and For example, two-stage sheet feeding units 18 are disposed below the image forming apparatus main body 12.

  Each of the paper feeding units 18 and 18 has a paper feeding unit main body 20 and a paper feeding cassette 22 in which paper is stored. The paper feed cassette 22 is slidably attached to the paper feed unit main body 20 and is pulled out in the front direction (right direction in FIG. 1). In addition, a feed roll 24 that supplies paper from the paper feed cassette 22 and a retard roll 26 that spreads the supplied paper one by one are disposed in the upper vicinity of the back end of the paper feed cassette 22.

  The conveyance path 28 is a paper path from the feed roll 24 of the lower sheet feeding unit 18 to the discharge port near the discharge roll 30, and the conveyance path 28 is the back surface of the image forming apparatus main body 12 (left side surface in FIG. 1). There is a portion in the vicinity that is formed substantially vertically from the feed roll 24 of the lower sheet feeding unit 18 to the fixing device 32 described later. A transfer device 34 and an image carrier 36 which will be described later are disposed on the upstream side of the fixing device 32 in the conveyance path 28, and a resist roll 38 is disposed on the upstream side of the transfer device 34 and the image carrier 36.

  Therefore, the sheet fed from the sheet feeding cassette 22 of the sheet feeding unit 18, 18 by the feed roll 24 is rolled by the retard roll 26 and guided to the transport path 28, temporarily stopped by the registration roll 38, and timed. A toner image is transferred between a transfer device 34 and an image carrier 36, which will be described later, and the transferred toner image is fixed by the fixing device 32 and discharged from the discharge port to the discharge unit 16 by the discharge roll 30. .

  The image forming unit 14 is of, for example, an electrophotographic system, and includes an image carrier 36, a charging roll 40 that uniformly charges the image carrier 36, and an image carrier 36 charged by the charging roll 40. An optical writing device 42 that writes a latent image by light, a developing device 44 that visualizes the latent image of the image carrier 36 formed by the optical writing device 42 with toner, and a toner image by the developing device 44 is transferred to a sheet. For example, the image forming apparatus includes a transfer device 34 composed of a transfer roll, a cleaning device 46 that cleans toner remaining on the image carrier 36, and a fixing device 32 that fixes the toner image on the paper transferred by the transfer device 34 to the paper. ing. The optical writing device 42 is composed of, for example, a scanning type laser exposure device, and is arranged in the vicinity of the front surface of the image forming apparatus main body 12 in parallel with the paper feeding units 18 and 18 described above, and the image carrier 36 is moved across the developing device 44. Exposure. The developing device 44 includes a toner container 48 and a developing roll 50 that adheres toner sent from the toner container 48 to a latent image on the image carrier. The cleaning device 46 includes a cleaning blade 52 as a cleaning member that comes into contact with the image carrier 36, and a toner recovery unit 54 that stores toner scraped off by the cleaning blade 52. In this embodiment, a scanning laser exposure apparatus is used as the optical writing device 42. However, as another embodiment, an LED, a surface emitting laser, or the like can be used.

  The process cartridge 56 is obtained by housing and integrating the image carrier 36, the charging roll 40, the developing device 44, and the cleaning device 46 in the process cartridge main body 58. The process cartridge 56 is supported so as to be detachable from the image forming apparatus main body 12.

  The open / close cover 60 is provided so as to be openable and closable with respect to the image forming apparatus main body 12. A manual feed tray 62 is disposed inside the opening / closing cover 60, and the manual feed tray 62 is connected to the transport path 28 when the manual feed tray 62 is tilted. Further, the transfer device 34 is supported by the opening / closing cover 60, and the process cartridge 56 can be taken out from the image forming apparatus main body 12 by opening the opening / closing cover 60.

  Further, an air blower 64 constituting air blowing means and a duct 66 constituting duct means are provided on the upper part of the process cartridge 56, and air from the air blower 64 is sent to the image carrier 36 through the duct 66 to carry the image. The body 36 is cooled.

In FIG. 2, details of the process cartridge 56 are shown.
The process cartridge main body 58 is provided with a handle portion 68, and the process cartridge 56 can be easily removed from the image forming apparatus main body 12 by grasping the handle portion 68 and pulling out the process cartridge 56.

  The developing device 44 has a developing chamber 70, and a developing roll 50 is disposed in the developing chamber 70. Further, the toner storage portion 48 is provided with a flexible stirring plate 72 such as PET (polyethylene terephthalate). The toner container 48 and the developing chamber 70 are connected via a toner supply port 74.

  The developing roll 50 has a magnet roll disposed therein, and the toner is attached to the roll surface by the magnetic force of the magnet roll. The developing roll 50 faces the image carrier 36 at, for example, the lower portion of the image carrier 36, and the opposed part is a development position. Further, the layer thickness regulating member 76 contacts the developing roll 50, and the thickness of the toner layer of the developing roll 50 is regulated by the layer thickness regulating member 76.

  As shown in FIG. 2, the protective cover 78 is formed on the process cartridge main body 58 so that the image carrier 36 faces the transfer device 34 when the process cartridge 56 is not attached to the image forming apparatus main body. Covering the opened opening. By covering the opening of the image carrier 36 in this way, the image carrier 36 is prevented from being damaged by a bite or light, and the image carrier 36 is protected.

  As shown in FIG. 3, the protective cover 78 is connected to a link 80 on the side of the process cartridge 56. The link 80 is rotatably supported by a support shaft 82 provided in the process cartridge main body 58, and the protective cover 78 is rotatably supported by the process cartridge main body 58 via the support shaft 82. Further, the opening / closing cover 60 is provided with a rib 84 that abuts against the link 80. When the opening / closing cover 60 is closed, the opening / closing cover 60 is closed as shown by a two-dot chain line in FIG. Along with this, the rib 84 presses and moves the link 80, whereby the protective cover 78 rotates clockwise to move away from the image carrier 36, and the image carrier 36 faces the transfer device 34.

  In FIG. 4, the fixing device 32, the duct 66, and the structure around them are shown. In the fixing device 32, a heating roll 88 and a pressure roll 90 are accommodated in a fixing device main body 86. The heating roll 88 is disposed obliquely downward and the pressure roll 90 is disposed obliquely upward. The heating roll 88 and the pressure roll 90 are in contact with each other with a nip portion 92. An inlet 94 and an outlet 96 are formed in the fixing device main body 86, and the sheet on which the toner is transferred enters from the inlet 94, and the toner is fixed by heat and pressure at the nip portion 92, and exits from the outlet 96. It is like that.

  The duct 66 is a passage from the blower 64 which is in the image forming apparatus main body 12 and is obliquely fixed to the image forming apparatus main body 12 to the discharge port 98 opened toward the image carrier 36, and the image forming apparatus main body 12. And a process cartridge main body 58 and a protective cover 78. The image forming apparatus main body 12 extends below the fixing device 32, and the protective cover 78 rotates clockwise when the open / close cover 60 is closed, and the other end of the protective cover 78 is the image forming apparatus main body 12. The duct 66 is in contact with the extended one end to ensure the sealing property of the duct 66. Therefore, it is possible to prevent leakage at the connection portion between the image forming apparatus main body 12 and the protective cover 78, and the air sent from the blower 64 is not affected by the heat from the fixing device 32 via the duct 66. It is efficiently discharged toward the image carrier 36. Further, the duct 66 is formed so that the width in the direction (vertical direction in FIG. 4) perpendicular to the axial direction of the image carrier 36 gradually narrows toward the discharge port 98, and the air flow rate is reduced. Therefore, the cooling efficiency of the image carrier 36 can be increased. The discharge port 98 is configured to be enclosed in a rectangular shape by the tip of the protective cover 78 and the process cartridge main body 58.

  In the above configuration, the sheet is fed from the sheet feeding cassette 22 selected from the sheet feeding unit 18 or 18 by the feed roll 24, is fed by the retard roll 26, is guided to the conveyance path 28, and is temporarily stopped by the registration roll 38. Is done. On the other hand, the image signal input to the image forming apparatus 10 is converted into laser light by the optical writing device 42, and this laser light is irradiated onto the image carrier 36 that is uniformly charged by the charging roll 40 to form a latent image. The latent image on the image carrier 36 is developed by the developing device 44 to become a toner image. Then, the toner image on the image carrier 36 is transferred by the transfer device 34 onto the paper fed at a predetermined timing by the registration roll 38, and the toner image is fixed on the paper by the fixing device 32, and is discharged through the discharge roll 30. It is discharged to the part 16.

  In the fixing device 32, heat is generated from the heating roll 90. When the image carrier 36 disposed in the vicinity of the fixing device 32 receives heat from the heating roll 90 and the temperature rises, toner offset and blade noise occur. However, in this embodiment, since the air blown from the blower 64 is blown out toward the image carrier 36 through the duct 66, the image carrier 36 is cooled, and toner offset and blade noise occur. Can be prevented.

  In order to eliminate the influence on the toner image formed on the image carrier 36, a wall is formed so that the blown air does not go to the transfer portion, or the blow is stopped during the transfer, and the blow is performed only during the non-transfer. You may do it.

  In FIG. 5, a second embodiment of the present invention is shown. The second embodiment is the same as the first embodiment in that the duct 66 includes the image forming apparatus main body 12, the process cartridge main body 58, and the protective cover 78. However, the protective cover 78 is opened. In this case, the lower end of the other end of the protective cover 78 is in contact with the upper end of the image forming apparatus main body 12 so as to overlap. Therefore, since the image forming apparatus main body 12 is joined so that the protective cover 78 is on the bottom, the air blown from a blower (not shown) can be more reliably prevented from leaking at the joined portion.

  In FIG. 6, a third embodiment of the present invention is shown. The third embodiment is the same as the first and second embodiments in that the duct 66 includes the image forming apparatus main body 12, the process cartridge main body 58, and the protective cover 78. On the contrary, the leading end is set as the suction port 100, and the image carrier is cooled by sucking air around the image carrier. Further, in the third embodiment, contrary to the second embodiment, when the protective cover 78 is opened, the upper end of the other end of the protective cover 78 is overlapped with the lower end of the image forming apparatus main body 12. In contact. Therefore, since the image forming apparatus main body 12 is joined so that the protective cover 78 is on the bottom, similarly to the second embodiment, leakage of air blown from a blower (not shown) at the joining portion is prevented. It can prevent more reliably.

  The portion for cooling the image carrier 36 is not limited to after the transfer, and may be anywhere around the image carrier 36. Further, the heat source for the image carrier 36 is not limited to the fixing device 32. For example, when there is a double-sided printing device, the double-sided printing device can be a heat source.

  As described above, the present invention can be used for an image forming apparatus that needs to cool an image carrier.

1 is a side view showing an image forming apparatus according to a first embodiment of the present invention. 1 is a cross-sectional view showing a process cartridge used in an image forming apparatus according to a first embodiment of the present invention. FIG. 2 is a side view showing a relationship between a protective cover used in the image forming apparatus according to the first embodiment of the present invention and an image carrier. 1 is a cross-sectional view illustrating a fixing device, a duct, and a peripheral structure thereof used in an image forming apparatus according to a first embodiment of the present invention. It is sectional drawing which shows the duct in the 2nd Embodiment of this invention. It is sectional drawing which shows the duct in the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 12 Image forming apparatus main body 14 Image forming means 32 Fixing device 36 Image carrier 56 Process cartridge 58 Process cartridge main body 60 Opening / closing cover 64 Blower 66 Duct 78 Protective cover 98 Discharge port 100 Suction port

Claims (11)

  An image carrier, a fixing device for fixing a toner image transferred from the image carrier to a sheet, a blower, and a duct provided with a port for sucking or discharging air by the blower toward the image carrier. And an image forming apparatus.   The image forming apparatus according to claim 1, wherein the duct unit is formed so that a width in a direction orthogonal to an axial direction of the image carrier gradually becomes narrower toward a port through which the air is sucked or discharged.   2. The image forming apparatus according to claim 1, further comprising a protective cover movably supported, wherein the protective cover moves to a position that protects the image carrier and a position that forms part of the duct means.   An image forming apparatus main body, a process cartridge that is detachably attached to the image forming apparatus main body and has an image carrier, and a toner image that is accommodated in the image forming apparatus main body and transferred from the image carrier. An image forming apparatus comprising: a fixing device that fixes a sheet; a blowing unit; and a duct unit that has a port through which air is sucked or discharged by the blowing unit toward the image carrier.   The image forming apparatus main body has an open / close cover for attaching and detaching the process cartridge, and the process cartridge further includes a protective cover that is movably supported, and the protective cover protects the image carrier. The image forming apparatus according to claim 4, wherein the image forming apparatus is moved in association with the opening / closing cover to a position where the opening / closing cover and a position constituting a part of the duct unit.   The image forming apparatus according to claim 5, wherein the process cartridge includes a process cartridge main body, and the duct unit includes the image forming apparatus main body, the process cartridge main body, and a protective cover.   The image forming apparatus according to claim 6, wherein the protective cover is in contact with the main body of the image forming apparatus when the protective cover is in a position constituting a part of the duct unit.   An image forming apparatus main body, an image carrier accommodated in the image forming apparatus main body, a fixing device which is accommodated in the image forming apparatus main body and fixes a toner image transferred from the image carrier to a sheet, The apparatus further includes a blowing unit, a duct unit provided with a discharge port for discharging air by the blowing unit toward the image carrier, and a protective cover that is movably supported. The protective cover includes the image carrier. When the protective cover is in a position constituting a part of the duct means, the connection portion formed in the image forming apparatus main body is moved to a position constituting a part of the duct means. An image forming apparatus configured to contact the outside.   An image forming apparatus main body, an image carrier accommodated in the image forming apparatus main body, a fixing device which is accommodated in the image forming apparatus main body and fixes a toner image transferred from the image carrier to a sheet, The apparatus further includes a blowing unit, a duct unit provided with an air inlet toward the image carrier by the blowing unit, and a protective cover supported movably. The protective cover protects the image carrier. And when the protective cover is located at a position constituting a part of the duct means, the inside of the connection portion formed on the image forming apparatus main body. An image forming apparatus configured to abut.   A process cartridge that is detachably attached to an image forming apparatus main body in which a fixing device is accommodated, and is movable relative to the process cartridge main body, an image carrier provided in the process cartridge main body, and the process cartridge main body The protective cover is provided at a position that protects the image carrier and a position that constitutes a part of the duct means, and a position that constitutes a part of the duct means. In this case, a process cartridge in which a tip of the protective cover constitutes a part of an opening opened toward the image carrier.   The process cartridge according to claim 10, wherein the duct means includes the process cartridge main body and a protective cover.

Images