JP5144184B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus in which process units such as a drum unit and a developing unit can be attached to and detached from a main body of an image forming apparatus.

  In an image forming apparatus such as a copying machine, a printer, or a facsimile that forms an image on a sheet by electrophotography, an electrostatic latent image formed on an image carrier such as a photosensitive drum is developed by a developing device to form a toner image. The toner image is visualized, and the toner image is transferred onto a sheet fed at an appropriate timing by a transfer device. The sheet onto which the toner image has been transferred is conveyed to a fixing device, and after the toner image is fixed by the fixing device, it is discharged out of the apparatus.

  In such an image forming apparatus, for the purpose of facilitating maintenance and the like, a photosensitive drum or the like is used as a drum unit, and a developing device is used as a developing unit to form a unit independent of other process devices. There is one that employs a configuration in which it is slid along a guide rail formed on an inner side wall to be attached to and detached from the image forming apparatus main body.

By the way, when the temperature in the main body of the image forming apparatus rises due to heat generated from the fixing device or the like, various problems such as toner melting occur, and therefore the outside air is introduced into the main body by a cooling fan to cool the inside of the main body. Various proposals related to cooling in the main body have been made so far (for example, see Patent Documents 1 to 3).
JP-A-5-224499 JP 2006-163136 A Japanese Patent Laid-Open No. 11-305634

  Thus, as image forming apparatuses such as copiers and printers are miniaturized, it becomes impossible to install a cooling fan or a fan motor that drives the cooling fan at a position where cooling is desired. It is also difficult to install a cooling duct.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an image forming apparatus capable of increasing the cooling efficiency in the main body with a simple configuration without causing an increase in size.

In order to achieve the above object, the present invention provides an image forming apparatus in which a process unit is slid along a guide rail formed on an inner wall of an image forming apparatus body, and is attached to and detached from the image forming apparatus body.
A resin guide member is attached to the inner surface of the sheet metal frame constituting the inner wall of the image forming apparatus , and a plurality of hollow convex portions are integrally projected on the guide member, and the guide is interposed between the convex portions. While forming the rail, the inside of the convex part is used as a cooling duct, and the cooling air is made to flow through the inside .
A plurality of ventilation holes are formed in the guide rail .

According to the present invention, a plurality of hollow convex portions are integrally provided on a resin guide member attached to the inner surface of a sheet metal frame that constitutes the inner wall of the image forming apparatus, and between these convex portions. As the guide rail is formed and the inside of the convex part is used as a cooling duct and the cooling air is made to flow inside it, it is not necessary to provide a space for installing the cooling duct separately, and space saving is realized. Without increasing the size of the image forming apparatus, it is possible to efficiently cool the inside of the image forming apparatus main body with a simple configuration by flowing cooling air inside the convex portion of the guide member that also functions as a cooling duct.

Further , according to the present invention, cooling air can be introduced into the main body of the image forming apparatus from a plurality of air holes formed in the guide rail, and the inside of the main body can be cooled extensively by the cooling air.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a side sectional view of a laser beam printer as an embodiment of an image forming apparatus according to the present invention. The illustrated laser beam printer 1 includes a paper feeding unit 2 provided at a lower portion of an apparatus main body 1a, and the paper supply unit. An image forming unit 3 provided at a substantially central portion in the apparatus main body 1 a above the paper unit 2, a fixing unit 4 disposed behind the image forming unit 3, and an apparatus main unit 1 a above the fixing unit 4. A paper discharge unit 5 provided above and a paper refeeding transport unit 6 for refeeding the paper to the image forming unit 3 by reversing the front and back when forming images on both sides of the paper are provided. Yes.

  The paper feed unit 2 stores paper and feeds the paper toward the image forming unit 3. The paper feed unit 2 includes a paper feed cassette 7 and a manual feed tray 8. The paper feed unit 2 includes a pickup roller 10 that picks up the sheets stacked on the paper stacking plate 9 in the paper feed cassette 7 one by one, and a feed that feeds the picked up paper to the horizontal part L1 of the transport path L. In addition to the paper rollers 11 to 15 and the registration roller pair 16 that is supplied to the transfer unit of the image forming unit 3 at a predetermined timing after temporarily waiting the fed paper, the paper placed on the manual feed tray 8 is taken out. A pickup roller 17 is provided.

  The image forming unit 3 forms an image on a sheet supplied from the sheet feeding unit 2, and is an image carrier that is rotatably disposed at a substantially central portion in the front-rear direction of the horizontal portion L 1 of the transport path L. A photosensitive drum 18, a charger 19 disposed around the photosensitive drum 18, a developing device 20, a transfer roller 21 and a cleaning device 22, a laser scanner unit (LSU) 23 disposed above them, a toner hopper 24, and the like. .

  The fixing unit 4 is for fixing the toner image transferred to the sheet in the image forming unit 3 to the sheet, and includes a heating roller 25 and a pressure roller 26 that are pressed against each other and rotated. Yes.

  Further, the paper discharge unit 5 is for discharging the paper on which the toner image has been fixed in the fixing unit 4 to the outside of the apparatus main body 1a, and is provided in the middle of the vertical portion L2 of the transport path L. A pair of transport rollers 27, a pair of paper discharge rollers 28 provided at the end of the vertical portion L2, and a paper discharge tray 29 for stacking sheets discharged to the outside of the apparatus main body 1a.

  The re-feed conveyance unit 6 is used when images are formed on both sides of a sheet, and includes another conveyance path L ′ arranged below the horizontal portion L1 of the conveyance path L and its conveyance path L ′. A plurality of conveyance roller pairs 30 provided at appropriate positions are provided.

  Next, an image forming operation of the laser beam printer 1 having the above configuration will be described.

  For example, when a print start signal is transmitted to the laser beam printer 1 from a terminal such as a personal computer (personal computer), in the image forming unit 3, the photosensitive drum 18 is driven in the direction indicated by the arrow (clockwise) in FIG. ) And the surface thereof is uniformly charged to a predetermined potential by the charger 19. Then, when laser light based on image data transmitted from the terminal is output from the laser scanner unit 23 and irradiated onto the photosensitive drum 18, an electrostatic latent image is formed on the photosensitive drum 18. Then, the electrostatic latent image formed on the photosensitive drum 18 is developed by the developing device 20 using toner as a developer to be visualized as a toner image.

  At the same time, in the paper feed unit 2, for example, the sheets stored in the paper feed cassette 7 are picked up one by one from the uppermost one by the pickup roller 10, and are fed to the registration roller pair 16 by the plurality of paper feed rollers 11 to 15. First, the paper is fed first, and is temporarily put into a standby state by the registration roller pair 16. Thereafter, the registration roller pair 16 is rotationally driven at a predetermined timing synchronized with the toner image on the photosensitive drum 18, and the sheet is transferred to a transfer portion that is a contact portion between the photosensitive drum 18 and the transfer roller 21 of the image forming unit 3. The paper is fed secondary.

  In the image forming unit 3, the paper supplied from the registration roller pair 16 to the transfer unit between the photosensitive drum 18 and the transfer roller 21 by the secondary paper feeding is conveyed while being pressed against the photosensitive drum 18 by the transfer roller 21. As a result, the toner image on the photosensitive drum 18 is transferred to the surface (transfer surface). The sheet onto which the toner image has been transferred is conveyed to the fixing unit 4, and is heated and pressed in the process of being sandwiched and conveyed between the heating roller 25 and the pressure roller 26 in the fixing unit 4. Get fixed. The toner remaining on the surface of the photosensitive drum 18 (transfer residual toner) after the transfer of the toner image onto the paper is removed by the cleaning device 22.

  Thus, the sheet on which the toner image is fixed on the surface by the fixing unit 4 is conveyed upward through the vertical portion L2 of the conveyance path L by the conveyance roller pair 27, and the upper portion of the apparatus main body 1a by the discharge roller pair 28. The paper is discharged and stacked on a paper discharge tray 29 provided at the front.

  Next, a cooling structure constituting the gist of the present invention will be described with reference to FIGS.

  2 to 4 are partial perspective views inside the image forming apparatus main body, FIG. 5 is a partial perspective view showing a guide rail formed on the inner wall surface of the image forming apparatus main body, and FIG. 6 is a fan motor mounting portion of the image forming apparatus main body. FIG.

In the laser beam printer 1 according to the present embodiment, the photosensitive drum 18 is unitized as a drum unit U1 (see FIG. 3), and the developing device 20 is unitized as a developing unit U2 (see FIG. 4). The drum unit U1 and the developing unit U2 are configured as process units independently of other process devices, and are attached to and detached from the image forming apparatus main body 1a as necessary. As shown in FIG. 4, a toner cartridge 31 is detachably attached to the developing unit U2. When the toner in the toner cartridge 31 is consumed and removed, the toner cartridge 31 is removed from the developing unit U2. It is removed and replaced with a new one.

  As shown in FIGS. 2 to 5, a sheet metal frame 32 constituting an inner wall is provided on both sides of the image forming apparatus main body 1 a (only one is shown in the figure), and the inner surface of each sheet metal frame 32. A resin guide member 33 is attached to each. In each guide member 33, three hollow convex portions 33A, 33B, 33C are integrally projected along the vertical direction, and the convex portions 33A, 33B are used as cooling ducts, Is formed with a flow path for flowing cooling air.

  Guide rails 34 and 35 are formed obliquely between the protrusions 33A and 33B and the protrusions 33B and 33C of each guide member 33, and the guide rails 34 and 35 include a plurality of guide rails 34 and 35. Circular hole-shaped air holes 36 and 37 are formed, respectively. As shown in FIG. 6, a rectangular frame-shaped fan holder 38 is attached to one sheet metal frame 32 of the image forming apparatus main body 1 a, and a fan motor 39 is disposed at the center of the fan holder 38. ing. A cooling fan (not shown) is attached to the output shaft of the fan motor 39.

  Thus, as shown in FIG. 2, from the state where neither the drum unit U1 nor the developing unit U2 is mounted in the image forming apparatus main body 1a, the guide rails 35 formed on the left and right inner walls of the main body 1a are connected to both side portions of the drum unit U1. By engaging a guide projection (not shown) projecting on the drum, holding the state and sliding the drum unit U1 along the guide rail 35 and pushing it inward, the drum unit U1 is imaged as shown in FIG. It can be mounted at a predetermined position in the forming apparatus main body 1a.

  After the drum unit U1 is mounted in the image forming apparatus main body 1a as described above, the guide rails (not shown) projecting on both sides of the developing unit U2 are engaged with the guide rails 34 formed on the left and right inner walls of the main body 1a. By holding the state and sliding the developing unit U2 along the guide rail 34 and pushing it inward, the developing unit U2 is mounted at a predetermined position in the image forming apparatus main body 1a as shown in FIG. can do.

  Thus, while the laser beam printer 1 shown in FIG. 1 is operating, a fan (not shown) is rotationally driven by the fan motor 39, and the outside air is cooled by the cooling fan as cooling air inside the image forming apparatus main body 1a. However, some of the cooling air introduced into the image forming apparatus main body 1a is formed on the convex portions 33A and 33B of the left and right guide members 33 functioning as cooling ducts as indicated by arrows in FIG. It flows into the image forming apparatus main body 1a through the flow path formed inside, and is used for cooling the drum unit U1, the developing unit U2, and other process equipment.

  The other part of the cooling air introduced into the image forming apparatus main body 1a flows into the image forming apparatus main body 1a from the plurality of air holes 36 and 37 formed in the left and right guide rails 34 and 35, and is connected to each part. Used for cooling.

  As described above, according to the cooling structure according to the present embodiment, the convex portions 33A and 33B of the existing guide member 33 forming the guide rails 34 and 35 are made hollow, and the convex portions 33A and 33B are cooled. Since the cooling air is used as a duct to flow inside the cooling duct, it is not necessary to provide a space for installing the cooling duct separately, and the cooling duct is realized without realizing space saving and increasing the size of the laser beam printer 1. Also, the inside of the image forming apparatus main body 1a can be efficiently cooled with a simple configuration by flowing cooling air inside the convex portions 33A and 33B of the guide member 33.

  In addition, cooling air can be introduced into the image forming apparatus main body 1a from the plurality of air holes 36 and 37 formed in the guide rails 34 and 35 so that the inside of the main body 1a can be cooled in a wide range by the cooling air.

  In the above, the embodiment in which the present invention is applied to a laser beam printer has been described. However, the present invention is not limited to a printer, but to any other image forming apparatus such as a copying machine, a facsimile machine, or a multifunction machine thereof. Of course, the same applies.

1 is a side sectional view of an image forming apparatus (laser beam printer) according to the present invention. FIG. 2 is a partial perspective view (a state where neither a drum unit nor a developing unit is mounted) inside the main body of the image forming apparatus according to the present invention. FIG. 2 is a partial perspective view (in a state where a drum unit is mounted) inside the main body of the image forming apparatus according to the present invention. FIG. 2 is a partial perspective view (a state where a drum unit and a developing unit are mounted) inside the main body of the image forming apparatus according to the present invention. It is a fragmentary perspective view which shows the guide rail formed in the main body inner wall surface of the image forming apparatus which concerns on this invention. FIG. 3 is a partial perspective view of a fan motor mounting portion of the image forming apparatus according to the present invention.

Explanation of symbols

1 Laser beam printer (image forming device)
DESCRIPTION OF SYMBOLS 1a Image forming apparatus main body 2 Paper feed part 3 Image formation part 4 Fixing part 5 Paper discharge part 6 Refeed conveyance part 7 Paper feed cassette 8 Manual feed tray 9 Paper stacking board 10 Pickup roller 11-15 Paper feed roller 16 Registration roller pair 17 Pickup Roller 18 Photosensitive Drum 19 Charger 20 Developing Device 21 Transfer Roller 22 Cleaning Device 23 Laser Scanner Unit (LSU)
24 toner hopper 25 heating roller 26 pressure roller 27 transport roller pair 28 paper discharge roller pair 29 paper discharge tray 30 transport roller pair 31 toner cartridge 32 sheet metal frame 33 guide member 33A to 33C guide member convex portions 34, 35 guide rail 36 , 37 Ventilation hole 38 Fan holder 39 Fan motor L, L 'Transport path L1 Transport path horizontal section L2 Transport path vertical section U1 Drum unit (process unit)
U2 Development unit (process unit)

Claims (1)

In the image forming apparatus in which the process unit is slid along the guide rail formed on the inner side wall of the image forming apparatus main body and is attached to and detached from the image forming apparatus main body.
A resin guide member is attached to the inner surface of the sheet metal frame constituting the inner wall of the image forming apparatus , and a plurality of hollow convex portions are integrally projected on the guide member, and the guide is interposed between the convex portions. While forming the rail, the inside of the convex part is used as a cooling duct, and the cooling air is made to flow through the inside .
An image forming apparatus, wherein a plurality of air holes are formed in the guide rail .

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