JP2010145733A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform more sufficient cooling processing of an image forming unit than heretofore in such a state that an apparatus cost is not increased. <P>SOLUTION: A transfer belt cooling mechanism 20, which is provided in an image forming apparatus 10 and for performing cooling processing for a transfer belt 125, includes: a first fan device 40 which is disposed in the vicinity of an intermediate transfer unit 12b and blows air for cooling toward the transfer belt 125; a second fan device 50 which is disposed in a position away from the first fan device 40 and for taking external air into the inside of a right surface exterior plate 30; and a ventilation duct 60 which is formed between the first and second fan devices 40 and 50. The ventilation duct 60 has a gap formed between an apparatus body 11 and the right surface exterior plate 30. In the gap, the right surface exterior plate 30 constitutes a portion of the wall surface of the ventilation duct 60. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus in which outside air for cooling is taken into an apparatus main body whose temperature is increased by image forming processing.

  2. Description of the Related Art Conventionally, an intake / exhaust device that is applied to an image forming apparatus as described in Patent Document 1 is known. This intake / exhaust device has a U-shape in a cross-sectional view integrally attached to the back side of the exterior cover and is used as an exhaust and intake duct, and a fan device provided on the reinforcement member It is configured with.

As the fan device, a charging unit intake fan that is provided in the vicinity of the charging unit and sucks outside air, a photosensitive member peripheral exhaust fan that is provided in the vicinity of the photosensitive member and exhausts the air around the charging unit, and a fixing device is provided. There are adopted four fans: a fixing unit peripheral exhaust fan that exhausts the surrounding air and an ozone exhaust fan that is provided in the vicinity of the paper transfer portion that transfers to the paper and exhausts the ozone-containing air around the fixing unit. . The outside air sucked by the drive of the intake fan is distributed to various places through the duct and used for the entire cooling process in the image forming apparatus.
JP-A-8-95474

  By the way, in the intake / exhaust device described in Patent Document 1, the outside air sucked by the charging unit intake fan is attracted to the exhaust processing by the photosensitive member peripheral exhaust fan, the fixing unit peripheral exhaust fan, and the ozone exhaust fan, and the various places. Therefore, it is totally floral and is not subjected to a cooling process in a single point.

  Therefore, particularly when attention is paid to a so-called image forming unit around the photosensitive drum, the exhaust of the outside air used for the cooling process of the charging unit is supplied to the image forming unit, which is sufficient for the cooling process of the image forming unit. There is a problem that air is not supplied and the image forming unit cannot be cooled effectively.

  The present invention has been made to solve the conventional problems as described above. In particular, the present invention is intended for an image forming unit and performs a sufficient cooling process as compared with the conventional apparatus without increasing the cost of the apparatus. An object of the present invention is to provide an image forming apparatus that can perform the above.

  The invention (image forming apparatus) according to claim 1 is an image forming unit for forming a toner image based on image information, and an intermediate transfer for performing secondary transfer onto a sheet while circulating the toner image primarily transferred from the image forming unit. An intermediate transfer unit including a belt; a housing frame that accommodates the image forming unit and the intermediate transfer unit; an exterior member that covers the housing frame; and the intermediate transfer unit disposed in the vicinity of the intermediate transfer unit. A first fan device that blows air toward the belt, a second fan device that is disposed at a position spaced apart from the first fan device and takes outside air into the exterior member, and the first and second fans A ventilation duct formed between the devices, the ventilation duct including a gap formed between the housing frame and the exterior member, and the outer duct It is characterized in that the member constitutes a part of the wall of the ventilation duct.

  According to such a configuration, since the outside air sucked through the second fan device, the ventilation duct, and the first fan device is blown to the intermediate transfer belt provided in the intermediate transfer unit, the circulating intermediate transfer is performed. The belt is cooled by being exposed to this air flow. As described above, since the outside air taken in from the outside by the second fan device is intensively supplied to the first fan device through the ventilation duct, the air is blown from the first fan device toward the intermediate transfer belt. Compared to the conventional case where the air in the image forming apparatus is collected by the first fan device and then blown again into the image forming apparatus, the air in the image forming apparatus is simply circulated. Thus, the disadvantage that the cooling effect is low is eliminated, and the intermediate transfer belt is subjected to a more effective cooling process.

  When the intermediate transfer belt is cooled, a predetermined member in the image forming unit that is in contact with the intermediate transfer belt for primary transfer is cooled by heat transfer, and the image forming unit is passed through the predetermined member. Various other components are also cooled.

  Further, a gap formed between the housing frame of the image forming apparatus and the exterior member covering the housing frame is used as a ventilation duct, and in particular, the exterior member constitutes a part of the wall surface of the ventilation duct. This eliminates the need to use a dedicated member as the duct, thereby contributing to the reduction in the number of parts and thus the production cost.

  According to a second aspect of the present invention, in the first aspect of the present invention, the ventilation duct includes the casing frame as a bottom plate, ribs protruding from the casing frame as side walls, and the exterior member as the side plate. It is used as a top plate that closes the opening of the space surrounded by the ribs.

  According to this configuration, the housing frame is provided with a pair of ribs parallel to each other, and the housing frame is used as the bottom plate of the ventilation duct by attaching the exterior member to the housing frame in this state. The projecting rib is used as a side wall of the ventilation duct, and the exterior member is used as a top plate of the ventilation duct that closes the opening of the space surrounded by the rib. As a result, the ventilation duct effectively uses the surrounding members. It will be formed.

  According to a third aspect of the present invention, in the second aspect of the present invention, the rib is formed of a foam.

  According to such a configuration, since the foam easily elastically deforms, the height of the rib is set slightly higher than the gap between the housing frame and the exterior member, so that the exterior member is attached to the housing frame. Since the rib is compressed by elastic deformation and is in close contact with the exterior member in a state where the is attached, the sucked outside air flows through the duct without leaking. Moreover, since it is not necessary to raise the dimensional accuracy of a rib, it contributes to the reduction of the construction cost of a ventilation duct.

  According to the image forming apparatus of the present invention, the outside air taken in by the second fan device is intensively guided to the first fan device via the ventilation duct, and the outside air is transferred to the intermediate transfer belt by the first fan device. Therefore, the intermediate transfer belt can be cooled more effectively than when the air in the conventional image forming apparatus is circulated to the member to be cooled.

  The predetermined member in the image forming unit that is in contact with the cooled intermediate transfer belt can be directly cooled by heat transfer, and various other components of the image forming unit can be passed through the predetermined member. As a result, the image forming unit can be subjected to a more effective cooling process than before.

  Further, a gap formed between the housing frame of the image forming apparatus and the exterior member covering the housing frame is used as a ventilation duct, and in particular, the exterior member constitutes a part of the wall surface of the ventilation duct. Therefore, it is not necessary to employ a dedicated member as the duct, which can contribute to a reduction in the number of parts and a reduction in manufacturing cost.

  1 and 2 are perspective views showing an embodiment of an image forming apparatus 10 according to the present invention. FIG. 1 shows a state in which a right exterior plate 30 as an exterior member is mounted on the apparatus main body 11, and FIG. These respectively show the state where the right side exterior plate 30 is removed from the apparatus main body 11. FIG. 3 is an explanatory diagram of a front cross-sectional view for explaining the outline of the internal structure of the image forming apparatus 10. 1 to 3, the XX direction is referred to as the left-right direction, and the YY direction is referred to as the front-rear direction. In particular, the -X direction is leftward, the + X direction is rightward, the -Y direction is frontward, and the + Y direction is backward. That's it.

  First, the image forming apparatus 10 shown in FIGS. 1 and 2 is a so-called in-body discharge type copier, and includes an image forming unit 12, a fixing unit 13, and a paper storage unit 14 in the apparatus main body 11. A paper discharge unit 15, an image reading unit 16, and an operation unit 17 are formed. Then, a part of the apparatus main body 11 is recessed below the image reading unit 16 to form the paper discharge unit 15. This is why the image forming apparatus 10 is referred to as an in-body discharge type.

  The apparatus main body 11 includes a lower main body (housing frame) 111 that has a rectangular parallelepiped shape in appearance, a flat main body 112 that has a flat rectangular parallelepiped shape disposed above the lower main body 111, and the upper main body 112. And a connecting body 113 interposed between the lower body 111 and the lower body 111. The connecting body 113 is a structure for connecting the paper discharge section 15 between the lower main body 111 and the upper main body 112 and is erected from the left and rear portions of the lower main body 111. In addition, it has an L shape in plan view. The upper main body 112 is supported by the upper end of the connecting body 113 at the left and the rear.

  The lower main body 111 includes an image forming unit 12, a fixing unit 13, and a paper storage unit 14, and an image reading unit 16 is mounted on the upper main body 112. In the present embodiment, the operation portion 17 is provided so as to protrude forward from the front edge portion of the upper main body 112.

  The paper discharge unit 15 is formed between the lower main body 111 and the upper main body 112. The paper discharge unit 15 has a cylinder discharge tray 151 formed on the upper surface of the lower main body 111, and the paper P onto which the toner image from the image forming unit 12 has been transferred is transferred from the lower part of the coupling body 113 to the cylinder P. The paper is discharged toward the inner paper discharge tray 151.

  Further, an openable / closable manual feed tray 145 is provided on the right surface of the lower main body 111. When the paper P is fed into the image forming apparatus 10 one by one, the manual feed tray 145 is pulled out, and the paper P is inserted into the manual feed tray 145. It is placed on the tray 145.

  Hereinafter, the image forming unit 12 will be described with reference to FIG. The image forming unit 12 forms a toner image on the paper P fed from the paper storage unit 14, and is sequentially arranged from the upstream side (right side) to the downstream side as shown in FIG. A magenta image forming unit 12M, a cyan image forming unit 12C, a yellow image forming unit 12Y, and a black image forming unit 12K are provided.

  Each of the image forming units 12M, 12C, 12Y, and 12K includes a photosensitive drum 121 as an image carrier and a developing device 122 that supplies toner to the photosensitive drum 121. Each photosensitive drum 121 is supplied with toner from the corresponding developing device 122 while rotating counterclockwise in FIG. A toner cartridge 129 is detachably mounted on the upper surface of the apparatus main body 11 (the front side of the paper surface in FIG. 3), and toner is supplied from the toner cartridge 129 to the corresponding developing device 122.

  A charging device 123 is provided immediately below each photoconductor drum 121, and an exposure device 124 is provided further below each charging device 123. Each photosensitive drum 121 is charged uniformly by the charging device 123, and laser light corresponding to each color based on image data read by the image reading unit 16 is charged from each exposure device 124. The photosensitive drum 121 is irradiated on the peripheral surface. Thereby, an electrostatic latent image is formed on the peripheral surface of each photosensitive drum 121. By supplying toner from the developing device 122 to the electrostatic latent image, a toner image is formed on the peripheral surface of the photosensitive drum 121.

  A transfer belt 125 is provided above the photoconductive drum 121 so as to come into contact with each photoconductive drum 121. The transfer belt 125 is wound around a driving roller 125a provided at the left position in FIG. 3 and a driven roller 125b provided at the right position.

  The transfer belt 125 is driven against a peripheral surface of the photosensitive drum 121 by a transfer roller 125c provided corresponding to each photosensitive drum 121, and is driven with a driving roller 125a and a driven roller while being synchronized with the photosensitive drum 121. Circulate between 125b.

  Accordingly, when the transfer belt 125 circulates, a magenta toner image is transferred onto the surface of the transfer belt 125 by the photosensitive drum 121 of the magenta image forming unit 12M, and then the cyan image forming unit 12C is located at the same position on the transfer belt 125. The cyan toner image is transferred on the photosensitive drum 121 in the overcoating state, and then the yellow toner image is transferred on the transfer belt 125 at the same position on the photosensitive drum 121 in the overcoating state. Then, the transfer of the black toner image by the photosensitive drum 121 of the last black image forming portion 12K is performed in the overcoating state.

  As a result, a color image is formed on the surface of the transfer belt 125. The color image formed on the surface of the transfer belt 125 is transferred to the paper P conveyed from the paper storage unit 14.

  A drum cleaning device 126 that removes and cleans the residual toner on the peripheral surface of the photosensitive drum 121 is provided at the left position of each photosensitive drum 121 in FIG. The peripheral surface of the photosensitive drum 121 cleaned by the drum cleaning device 126 goes to the charging device 123 for a new charging process.

  Waste toner removed from the peripheral surface of the photosensitive drum 121 by the drum cleaning device 126 is collected in a toner collection bottle (not shown) through a predetermined path.

  A sheet conveyance path 127 extending in the vertical direction is provided at the left position of the image forming unit 12. The paper transport path 127 is provided with a transport roller pair 127a at an appropriate position, and the paper P from the paper storage unit 14 is directed toward the transfer belt 125 that is wound around the drive roller 125a by the drive of the transport roller pair 127a. Be transported.

  In the sheet conveyance path 127, a secondary transfer roller 128 that is in contact with the surface of the transfer belt 125 is provided at a position facing the driving roller 125a. Then, the paper P being conveyed through the paper conveyance path 127 is pressed and held between the transfer belt 125 and the secondary transfer roller 128, whereby the toner image on the transfer belt 125 is transferred to the paper P.

  A belt cleaning device 125 d that removes residual toner remaining on the surface of the transfer belt 125 is provided on the right side of the transfer belt 125. The transfer belt 125 that has completed the transfer process to the paper P is circulated toward the next transfer process in a state where residual toner on the surface is removed and cleaned by the belt cleaning device 125d.

  The fixing unit 13 performs a fixing process on the toner image on the paper P transferred by the image forming unit 12. The fixing unit 13 includes a fixing roller 131 including an energization heating element such as a halogen lamp as a heating source. The pressure roller 132 disposed opposite to the fixing roller 131 is provided on the left side. Then, the transfer-processed paper P derived from the image forming unit 12 through the secondary transfer roller 128 is pressed and sandwiched between the fixing roller 131 and the pressure roller 132, and the toner image is heated by the fixing roller 131. Is fixed, and a stable color image is formed on the paper P.

  The color-printed paper P for which the fixing process has been completed passes through a paper discharge conveyance path 133 extending from the upper part of the fixing unit 13 and is discharged toward the in-body paper discharge tray 151 via the discharge roller pair 152. .

  The paper storage unit 14 includes a paper feed tray 141 that is detachably mounted at a position below the exposure device 124 in the apparatus main body 11, and a manual feed tray 145 that can be opened and closed at the lower right side of the apparatus main body 11. ing. A sheet bundle is stored in the sheet feeding tray 141. Then, the sheet P is fed out from the sheet bundle stored in the sheet feeding tray 141 one by one by the drive of the pickup roller 142, and is introduced into the image forming unit 12 through the sheet conveying path 127.

  On the other hand, the manual feed tray 145 is for manually feeding the paper P one by one to the image forming unit 12. A manual feed roller pair 146 is provided in the vicinity of the rotation fulcrum at the bottom of the manual feed tray 145. Further, a manual feed path 147 is provided between the manual feed roller pair 146 and the sheet feed path 127 immediately below the pair of carry rollers 127a. The paper P manually fed from the manual feed tray 145 is introduced into the paper transport path 127 through the manual roller pair 146, the manual transport path 147, and the transport roller pair 127a, and is subjected to a transfer process in the image forming unit 12. .

  The image reading unit 16 presses the contact glass 161 mounted on the upper surface opening of the upper main body 112 on which the document P1 is placed with the document surface facing down, and the document placed on the contact glass 161. A document pressing cover 162 that is openable and closable with respect to the contact glass 161, and an optical system unit 163 built in the upper body 112 for reading a document image of the document P1 placed on the contact glass 161. I have.

  The optical system unit 163 scans a document image from below the document surface by moving the light source 164 via the contact glass 161 from below while the document placed on the contact glass 161 is pressed by the document pressing cover 162. It is read by a CCD (charge coupled device) 165 by the reflected light. The document image information read by the CCD 165 is output to the exposure device 124 of the image forming unit 12 after being digitized.

  The operation unit 17 is used to input various items (paper size, number of processing copies, etc.) related to image forming processing. As shown in FIG. 1, the operation unit 17 includes a start key 171, a numeric keypad 172 for inputting numerical information, and an LCD (Liquid crystal display) for displaying input information, an error message, and the like by the numeric keypad 172 that is actually performed. 173 etc. are provided.

  The image forming apparatus 10 configured as described above is provided with a transfer belt cooling mechanism 20 that performs a cooling process on the transfer belt 125, as shown in FIG. The transfer belt cooling mechanism 20 is provided on a right frame plate 111 d described later, which is a component of the lower main body (housing frame) 111.

  Hereinafter, the lower body 111 will be described with reference to FIG. The lower main body 111 includes a bottom plate 111a having a substantially square shape in plan view, four support columns 111b erected at the four corners of the bottom plate 111a, and four of these at a substantially intermediate position in the vertical direction of the lower main body 111. The intermediate shelf frame 111c supported by the column 111b and the container support plate 114 supported by the four columns 111b at the uppermost position of the lower body 111 are provided.

  A paper feed tray 141 (FIG. 1) is detachably mounted between the bottom plate 111a and the intermediate shelf frame 111c.

  The intermediate shelf frame 111c supports the image forming unit 12a. The image forming unit 12a includes a photosensitive drum 121, a developing device 122, a charging device 123, a drum cleaning device 126, and the like that are components of the image forming units 12M, 12C, 12Y, and 12K in a predetermined casing 120. Each is configured to be installed. At the time of maintenance work such as inspection and repair, the image forming unit 12a is pulled out from the lower main body 111, whereby maintenance work of various members in the image forming unit 12a can be easily performed.

  The intermediate transfer unit 12b is wound around a predetermined frame frame 1250 having a rectangular shape in plan view, the driving roller 125a and the driven roller 125b mounted on the frame frame 1250, and both the rollers 125a and 125b. The transfer belt 125 is provided.

  The intermediate transfer unit 12b is detachably attached to the lower main body 111, and the maintenance operation can be easily performed in the pulled-out state in the case of the previous image forming unit 12a. It is the same.

  The container support plate 114 is supported by four columns 111 b at a position directly above the intermediate transfer unit 12 b in the lower main body 111. A mounting recess 114 a extending in the front-rear direction for mounting the four toner cartridges 129 is provided on the upper surface side of the container support plate 114. A cartridge mounting space is formed between the mounting recess 114a and the in-body discharge tray 151. The toner cartridge 129 is attached to and detached from the mounting recess 114a with the front door 1110 (FIG. 1) being opened.

  A fan support plate 114b for supporting a first fan device 40, which will be described later, is set on the right side of the container support plate 114, and is suspended downward from the right edge of the fan support plate 114b. A right frame plate 111d as a component constituting a part of the lower main body 111 is provided. The right frame plate 111d is constructed between the right and left support pillars 111b.

  Further, on the back surface (rear surface) of the lower main body 111, a back plate 111e is provided between a pair of rear columns 111b. Further, the right exterior plate 30 is attached to the right surface of the lower main body 111 so as to extend between the front and rear columns 111b on the outer surface side of the right frame plate 111d.

  Hereinafter, the transfer belt cooling mechanism 20 attached to the lower main body 111 will be described with reference to FIGS. 4 and 5 are partially enlarged perspective views of FIG. 2 for explaining an embodiment of the transfer belt cooling mechanism 20, FIG. 4 is a partially cutaway exploded perspective view, and FIG. 5 is an assembled perspective view thereof. FIG. 6 is a sectional view of the transfer belt cooling mechanism 20 shown in FIG. 4 to 6 are the same as those shown in FIG. 1 (-X: leftward, + X: rightward, -Y: forward, + Y: backward).

  4 to 6, the transfer belt cooling mechanism 20 includes a right frame plate (housing frame) 111d that is a component of the lower main body 111, and a right exterior plate (exterior member) that covers the right frame plate 111d. ) 30 and a first fan device 40 that is attached to the fan support plate 114b and is disposed in the vicinity of the right end of the intermediate transfer unit 12b, and blows airflow toward the intermediate transfer belt, and the first fan device 40. Is disposed at a position spaced apart from the rear surface plate 111e (specifically, the inner surface side of the back plate 111e), and outside air is taken into the right surface outer plate 30 (a gap between the right surface outer plate 30 and the right frame plate 111d). For this purpose, and a ventilation duct 60 formed between the first and second fan devices 40, 50.

  That is, the right side exterior plate 30 corresponding to the exterior member of the present invention constitutes a part of the wall surface of the ventilation duct 60 in the gap.

  The upper part of the first fan device 40 is fitted into a mounting groove 114c formed by cutting out the central part in the front-rear direction of the fan support plate 114b. The first fan device 40 includes a first casing 41 having a rectangular parallelepiped shape, a first fan motor 42 provided in the first casing 41 so that the motor shaft 421 extends in the left-right direction, and a circumferential direction on the motor shaft 421. And a plurality of propeller fans 43 fixed at an equal pitch.

  An upper portion of the first casing 41 has flanges 411 formed on the front and rear side surfaces and the left surface. The first fan device 40 is attached to the fan support plate 114b by fitting a portion below the flange 411 of the first casing 41 into the mounting groove 114c and performing screwing or the like.

  The first fan motor 42 sucks the airflow sent from the second fan motor 52 through the ventilation duct 60 and blows it on the upper surface of the transfer belt 125, thereby cooling the transfer belt 125. The first fan motor 42 is configured such that the tips of the four support rods 422 projecting up and down and front and rear from the peripheral surface are fixed to the corresponding inner wall surfaces of the first casing 41. 41.

  The left surface of the first casing 41 is fully open, while the right surface is closed by a right side plate 412. The right side plate 412 is provided with a fan side louver 413, and the airflow formed by the driving rotation of the propeller fan 43 around the motor shaft 421 is sucked into the first casing 41 through the fan side louver 413, The air is blown from the opening on the left surface of the casing 41 toward the upper surface on the right end of the transfer belt 125.

  In the present embodiment, the second fan device 50 is provided with a later-described Siccoro fan 53 configured to suck outside air in the axial direction and blow it out in the circumferential direction. The lower body 111 is mounted at a position above the right rear corner. The second fan device 50 includes a cylindrical second casing 51 that is mounted on the back plate 111e with a cylindrical core directed in the front-rear direction, and a second casing 51 that is concentrically mounted on the front side of the second casing 51. A two-fan motor 52 and a sickro fan 53 concentrically attached to a drive shaft 521 of the second fan motor 52 so as to be integrally rotatable are provided.

  On the outer peripheral surface of the rear edge portion of the second casing 51, there are provided a plurality of mounting pieces 511 protruding at equal pitches in the circumferential direction, and these mounting pieces 511 are bolted to the back plate 111e. The second casing 51 is attached to the back plate 111e. The second casing 51 has a rear surface opened to serve as an outside air intake. In addition, an outside air suction louver 111f is formed at a position facing the outside air intake port on the back plate 111e. In addition, an airflow blowing cylinder 512 having a flat rectangular shape in a cross-sectional view protruding in the tangential direction toward the right is provided at a position above the peripheral surface of the second casing 51.

  The Siccoro fan 53 is concentrically provided with a cylindrical shaft 531 attached to the driving shaft 521 so as to be integrally rotatable with the driving shaft 521 of the second fan motor 52, and a plurality of the cylindrical shafts 531 projecting at equal pitches in the circumferential direction. Connecting rods 532, and a Siccoro fan main body 533 concentrically supported by these connecting rods 532. The cylindrical shaft 531 has a rear surface opened, and a plurality of flow holes are formed in the circumferential surface of the central portion of the cylindrical shaft 531 for allowing air currents provided at equal pitches in the circumferential direction. Yes.

  The Siccoro fan main body 533 includes a pair of front and rear annular bodies 533a and a plurality of blades 533b laid between the pair of annular bodies 533a at equal pitches in the circumferential direction. Each vane plate 533b is provided to be inclined with respect to the radial direction. As a result, the air blown outward in the radial direction is generated by rotating the Siccoro fan main body 533 in a predetermined direction.

  According to the second fan device 50 having such a configuration, when the second fan motor 52 is driven to rotate the sickro fan 53 in a predetermined direction, the inside of the first fan fan 53 becomes negative pressure by the action of the blade plate 533b. 111e passes through the outside air suction louver 111f and the cylindrical shaft 531 and is sucked into the cigarette fan main body 533, supplied into the second casing 51 through the blade plate 533b, and discharged from the airflow blowing cylinder 512 into the lower main body 111. The

  On the other hand, the right frame plate 111d is provided with a first louver 44 at a position facing the fan-side louver 413 of the right-side plate 412 of the first fan device 40, and an air flow blowout of the second fan device 50. A second louver 54 is provided at a position facing the cylinder 512. A ventilation duct 60 is provided so as to surround the first and second louvers 44 and 54.

  In the present embodiment, the ventilation duct 60 includes a right frame plate 111d, a foam rib 61 having a U-shape that is reversed to the front in the right view on the outer surface side of the right frame plate 111d, and the rib. 61 and the right exterior plate 30 that covers the right surface of the lower main body 111 so as to contact the right edge surface of the lower body 111. In the present embodiment, the rib 61 is attached to the back side (left side) of the right side exterior plate 30. Therefore, the ventilation duct 60 is formed between the right side frame plate 111 d and the right side exterior plate 30 by attaching the right side exterior plate 30 to the apparatus main body 11. The rib 61 may be attached to the right frame plate 111d side.

  The rib 61 is an upper rib 611 that extends in the front-rear direction and is attached to a position corresponding to a position slightly above the first and second louvers 44, 54 in the right exterior plate 30, and a front end portion of the upper rib 611. A vertical rib 612 that hangs slightly forward from the first louver 44, and a lower rib 613 that extends from the slightly lower position of the first louver 44 toward the rear at the lower end of the vertical rib 612. It is formed in an inverted U shape. The thickness dimension of the rib 61 in the left-right direction is based on the gap dimension between the right-side exterior plate 30 and the right-side frame plate 111d in a state where the right-side exterior plate 30 is mounted on the right side of the lower main body 111 of the image forming apparatus 10. It is set a little thicker.

  Therefore, the back surface (left surface) of the right surface exterior plate 30 is in close contact with the right edge surface of the compression-elastically deformed rib 61 in a state where the right surface exterior plate 30 is mounted on the right surface of the lower main body 111. The ventilation duct 60 having a space surrounded by the right-side exterior plate 30, the right-side frame plate 111d, and the rib 61 can circulate airflow from the second louver 54 toward the first louver 44 without leakage.

  Therefore, in the ventilation duct 60, the portion surrounded by the rib 61 in the right frame plate 111d is the bottom plate of the ventilation duct 60. Further, the upper rib 611, the vertical rib 612 and the lower rib 613 projecting from the right frame plate 111 d are the side walls of the ventilation duct 60. Further, the right side exterior plate 30 functions as a top plate that closes the opening between the ribs 611, 612, and 613.

  As described above in detail, the image forming apparatus 10 according to the present exemplary embodiment includes the image forming unit 12a that forms a toner image based on image information, and the sheet of paper that circulates the toner image that is primarily transferred from the image forming unit 12a. An intermediate transfer unit 12b having a transfer belt 125 disposed immediately above the image forming unit 12a, an apparatus main body 11 housing the image forming unit 12a and the intermediate transfer unit 12b, and the apparatus main body 11. A covering member (in particular, a right side covering plate 30 covering the right side of the lower main body 111) and a transfer belt cooling mechanism 20 that performs a cooling process on the transfer belt 125 of the intermediate transfer unit 12b are provided.

  The transfer belt cooling mechanism 20 is disposed in the vicinity of the intermediate transfer unit 12 b, and is disposed at a position away from the first fan device 40 that blows an airflow for cooling toward the transfer belt 125. And a second fan device 50 for taking outside air into the right side exterior plate 30 and a ventilation duct 60 formed between the first and second fan devices 40, 50.

  The ventilation duct 60 has a gap formed between the apparatus main body 11 and the right side exterior plate 30, and the right side exterior plate 30 forms a part of the wall surface of the ventilation duct 60 in the gap.

  By configuring the transfer belt cooling mechanism 20 in this way, the transfer belt 125 provided in the intermediate transfer unit 12b is brought into the outside air sucked through the second fan device 50, the ventilation duct 60, and the first fan device 40. Since the toner is blown, the circulating transfer belt 125 is cooled by being exposed to the blown airflow.

  As described above, the outside air taken in from the outside by the second fan device 50 is supplied to the first fan device 40 through the ventilation duct 60 and is blasted toward the upper surface of the transfer belt 125 by the first fan device 40. I have to. Therefore, if the air in the image forming apparatus 10 is collected only by the first fan device 40 and circulated and blown again into the image forming apparatus 10 as in the prior art, the amount of outside air taken in is limited, and sufficient cooling is performed. Although there is a disadvantage that the effect cannot be obtained, the transfer belt cooling mechanism 20 according to the present embodiment eliminates this disadvantage, and the transfer belt 125 can be cooled more effectively.

  The cooling air from the first fan device 40 passes through the upper surface of the transfer belt 125 and reaches the left paper transport path 127 (FIG. 3), then rises up the paper transport path 127 and widens the paper transport path 127. It moves to a direction (front-back direction orthogonal to the paper surface of FIG. 3), and is exhausted outside from the exhaust port 111g (shown with a dotted line in FIG. 3) provided in the back plate 111e of the apparatus main body 11.

  When the transfer belt 125 is cooled, the photosensitive drum 121 in the image forming unit 12a that is in contact with the transfer belt 125 can be subjected to a more effective cooling process by heat transfer. Various other components of the image forming unit (developing device 122, charging device 123, exposure device 124, drum cleaning device 126, etc.) can also be cooled by the cold heat from the belt 125. As a result, the image forming unit 12a A more effective cooling process can be applied, which has been increased compared to the prior art.

  Further, a gap formed between the apparatus main body 11 of the image forming apparatus 10 and the exterior member covering the apparatus main body 11 is used as the ventilation duct 60, and in particular, the exterior member constitutes a part of the wall surface of the ventilation duct 60. Therefore, it is not necessary to employ a dedicated member as the duct, and accordingly, it is possible to contribute to a reduction in the number of parts and a reduction in manufacturing cost.

  In this embodiment, the right frame plate 111d of the lower main body 111 is used as the bottom plate of the ventilation duct 60, and the ribs 61 projecting from the right frame plate 111d are used as the side walls of the ventilation duct 60. 30 is used as a top plate for closing the opening between the ribs 61.

  By configuring the ventilation duct 60 in this way, a space surrounded by the ribs 61 between the right frame plate 111d and the right exterior plate 30 without adopting a dedicated cylindrical body such as a pipe, particularly for the duct. Thus, the ventilation duct 60 can be formed, which can contribute to a reduction in the manufacturing cost of the duct.

  And in this embodiment, since the rib 61 is formed with the foam, the foam can be easily elastically deformed. Therefore, by setting the height dimension of the rib 61 to be slightly higher than the gap dimension between the apparatus main body 11 and the right side exterior plate 30 in advance, the rib 61 is mounted in the state where the right side exterior plate 30 is mounted on the apparatus main body 11. Since 61 is compressed by elastic deformation and is in close contact with the right exterior plate 30, the sucked outside air can be circulated in the duct without leaking. Moreover, since it is not necessary to raise the dimensional accuracy of the rib 61, it can contribute to the reduction of the construction cost of the ventilation duct 60. FIG.

  The present invention is not limited to the above embodiment, and includes the following contents.

  (1) In the above embodiment, a copying machine has been described as an example of the image forming apparatus 10 according to the present invention. However, instead of the copying machine, a printer or a facsimile machine may be used. .

  (2) In the above embodiment, a foam is adopted as the rib 61. However, the foam 61 is not particularly limited to the foam, and the rib 61 is formed of other materials such as rubber, synthetic resin, and metal. May be.

  (3) In the above-described embodiment, a propeller fan is used as the first fan device 40 and a cycloro fan is used as the second fan device 50. However, a reverse fan is used as the first fan device 40. A propeller fan may be adopted as the second fan device 50, both the first and second fan devices 40, 50 may be propeller fans, or both the first and second fan devices 40, 50 may be used. May be a sickro fan. Which combination is used may be determined according to the actual situation of the image forming apparatus.

  (4) In the above embodiment, various members for image formation including the photosensitive drum 121, the developing device 122, the charging device 123, the exposure device 124, the drum cleaning device 126 and the like are disposed below the transfer belt 125. The image forming apparatus 10 has been described as an example, but the image forming apparatus according to the present invention includes an embodiment in which various members for image formation are disposed above the transfer belt 125.

1 is a perspective view showing an embodiment of an image forming apparatus according to the present invention, and shows a state where a right side exterior plate as an exterior member is mounted on the apparatus main body. 1 is a perspective view showing an embodiment of an image forming apparatus according to the present invention, and shows a state where an exterior member is removed from the apparatus main body. It is explanatory drawing of front sectional view for demonstrating the outline of the internal structure of an image forming apparatus. FIG. 3 is a partially cutaway partial enlarged perspective view of FIG. 2 for describing an embodiment of a transfer belt cooling mechanism. FIG. 5 is an assembled perspective view of the transfer belt cooling mechanism shown in FIG. 4. FIG. 6 is a cross-sectional view in plan view of the transfer belt cooling mechanism shown in FIG. 5.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 11 Apparatus main body 111 Lower main body (housing frame)
1110 Front door 111a Bottom plate 111b Post 111c Middle shelf frame 111d Right frame plate (housing frame)
111e Back plate 111f Outside air suction louver 111g Exhaust port 112 Upper body 113 Connecting body 114 Container support plate 114a Mounting recess 114b Fan support plate 114c Mounting groove 12 Image forming unit 12M Magenta image forming unit 12C Cyan image forming unit 12Y For yellow Image forming unit 12K Image forming unit 12a for black Image forming unit 120 Casing 121 Photoconductor drum 122 Developing device 123 Charging device 124 Exposure device 12b Intermediate transfer unit 1250 Frame frame 125 Transfer belt 125a Drive roller 125b Driven roller 125c Transfer roller 125d Belt cleaning Device 126 Drum cleaning device 127 Paper transport path 127a Transport roller pair 128 Secondary transfer roller 129 Toner cartridge 13 Fixing unit 131 Fixing Roller 132 Pressure roller 133 Paper delivery path 14 Paper storage part 141 Paper feed tray 142 Pickup roller 145 Manual feed tray 146 Manual feed roller pair 147 Manual feed path 15 Paper delivery part 151 In-body paper delivery tray 152 Paper discharge pair 16 Image reading part 161 Contact glass 162 Document cover 163 Optical system unit 164 Light source 17 Operation unit 171 Start key 172 Numeric keypad 173 LCD (Liquid crystal display)
20 Transfer belt cooling mechanism 30 Right side exterior plate (exterior member)
40 first fan device 41 first casing 411 flange 412 right side plate 413 fan side louver 421 motor shaft 422 support rod 42 first fan motor 43 propeller fan 44 first louver 50 second fan device 51 second casing 511 mounting piece 512 airflow Blowout cylinder 52 Second fan motor 521 Drive shaft 53 Siccoro fan 531 Cylinder shaft 532 Connecting rod 533 Siccoro fan main body 533a Annular body 533b Blade plate 54 Second louver 60 Ventilation duct 61 Rib 611 Upper rib 612 Vertical rib 613 Lower rib P Paper P1 Document

Claims (3)

An image forming unit for forming a toner image based on image information;
An intermediate transfer unit comprising an intermediate transfer belt for secondary transfer to the paper while circulating the toner image primarily transferred from the image forming unit;
A housing frame that houses the image forming unit and the intermediate transfer unit;
An exterior member covering the housing frame;
A first fan device disposed near the intermediate transfer unit and blowing air toward the intermediate transfer belt;
A second fan device disposed at a position spaced apart from the first fan device and for taking outside air into the exterior member;
A ventilation duct formed between the first and second fan devices,
The ventilation duct includes a gap formed between the housing frame and the exterior member,
In the gap, the exterior member constitutes a part of the wall surface of the ventilation duct.   The ventilation duct is used as a top plate for closing the opening of the space surrounded by the ribs, with the housing frame serving as a bottom plate, ribs protruding from the housing frame as side walls, and the exterior member being surrounded by the ribs. The image forming apparatus according to claim 1, wherein: The image forming apparatus according to claim 2, wherein the rib is formed of a foam.

Images