JP2005010767A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently and also effectively cool the inside of an apparatus main body 2 and plain paper P which is subjected to thermal fixing by a fixing means 60. <P>SOLUTION: An image forming means 100A, the fixing means 60 and an ejection feeding path 64 to feed the plain paper P with a toner image thermally fixed to an ejection tray 12 are disposed in the apparatus main body 2. The ejection feeding path 64 is extended in an up-and-down direction along the back side wall 6 of the apparatus main body 2. A cooling fan 72 to generate an air flow directed from the side of the image forming means 100A to the ejection feeding path 64 is disposed at inside opposed to the ejection feeding path 64. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus using an electrophotographic system, such as a copying machine, a printer, a facsimile machine, or a multifunction machine thereof, and more particularly, to an inside of an apparatus main body and a recording medium heated by passing through a fixing device. The present invention relates to an image forming apparatus including a cooling unit capable of cooling both.

  In the main body of an electrophotographic image forming apparatus such as a copying machine, a printer, a facsimile machine, or a complex machine of them, for example, fixing for thermally fixing a toner image transferred to a recording medium such as plain paper A recording medium on which a toner image is thermally fixed by a fixing device, a conveyance medium, an electric motor as a driving source, an electromagnetic clutch for connecting / disconnecting a driving force, an exposure light source, a control circuit, etc. are provided. It is a heat source that raises the temperature inside the body. In particular, in a tandem type color image forming apparatus provided with image forming means including the same number of process units as the number of toner colors, an LED head may be used because of a demand for miniaturization. The temperature of the electric motor that rotationally drives the body drum rises with the image forming operation, which is a major factor that raises the temperature in the apparatus main body (the LED head, the photosensitive drum, and the electric motor are provided for each process unit). One for each). In particular, as the overall apparatus becomes smaller, the interval between the process units becomes narrower, and therefore, the tendency of the temperature inside the apparatus body to rise further increases. Further, in order to stably maintain the gloss (glossiness) of the color image within a desired range, it is necessary to sufficiently melt the toner image more than the monochrome image. For this reason, when heating means such as a halogen heater is incorporated in the upper and lower fixing rollers, the temperature in the main body of the apparatus and the temperature of the recording medium on which the toner image is thermally fixed by the fixing apparatus are increased. The trend is even higher. If the temperature in the apparatus main body becomes excessively high, the toner stored in the developing device and the toner collected in the cleaning device may be solidified. Further, if the temperature of the recording medium on which the toner image is thermally fixed becomes excessively high, the recording medium may stick to another recording medium when discharged onto the tray.

  From such a technical background, it can be said that cooling the image forming apparatus main body and the recording medium on which the toner image is thermally fixed are extremely important. By the way, as a conventional image forming apparatus provided with this kind of cooling means, for example, the one disclosed in the following patent document can be cited.

  In the image forming apparatus disclosed in Patent Document 1, an upstream image forming unit and a downstream image forming unit are arranged in the apparatus main body so that the conveyance directions of the recording media (transfer materials) are alternately arranged. It is installed. The upstream image forming unit and the downstream image forming unit are connected by a single connection path. By conveying the recording medium through the one connection path, images can be formed on both sides of the recording medium. Inside the apparatus main body, a cooling fan and a duct suck air from the outside of one side of the apparatus main body through the connection path, and also suck heat generated by the fixing device and exhaust it from the rear side of the apparatus main body to the outside. It is provided as follows. The aim of the image forming apparatus configured in this way is to forcibly cool the connection path, so that the temperature of the downstream image forming unit is increased by the high-temperature recording medium conveyed from the upstream image forming unit. And preventing solidification of the toner stored in the developer.

  The image forming apparatus disclosed in Patent Document 2 is configured such that a recording medium (sheet) on which a toner image is thermally fixed is discharged to a plurality of trays from a plurality of discharge ports provided in the apparatus main body. Yes. This apparatus includes common cooling means for blowing air toward the recording medium discharged from the discharge port and the recording medium discharged to the tray to cool the recording medium. The cooling means includes a cooling fan and a plurality of ducts for guiding air sucked by the cooling fan toward a plurality of trays. At the same time, it is intended to cool the inside of the apparatus. The aim of the image forming apparatus configured in this way is to prevent sticking of the recording medium discharged to the tray without increasing the cost and increasing the size of the apparatus.

  An image forming apparatus disclosed in Patent Document 3 includes an input unit that inputs a type of a recording medium (transfer material), a fixing unit that thermally fixes a toner image on the recording medium, and a recording medium on which the toner image is thermally fixed. A transport unit that transports from the fixing unit to the discharge port, a cooling fan that blows air onto the recording medium that is being transported by the transport unit, and a cooling fan that operates when a specific recording medium type is input by the input unit And control means for causing the The cooling fan is disposed outside the conveyance path included in the conveyance means. When the type of a specific recording medium is input by the input means, the cooling fan is actuated, and the air sucked from the outside of the apparatus main body is blown onto the recording medium in the middle of conveyance, thereby cooling the recording medium. The aim of the image forming apparatus configured as described above is that a specific recording medium (for example, after the toner image is fixed by heat) without increasing the operating sound when a normal recording medium such as plain paper is used. , OHP recording medium) is quickly cooled to prevent scratches from occurring when the OHP recording medium is in a high temperature state and the hardness is lowered when passing through a conveyance path, particularly a bent conveyance path. It is to be.

  Patent Document 4 discloses an image forming apparatus in which a paper discharge unit is arranged immediately after a fixing unit. The image forming apparatus includes a cooling fan provided in the vicinity of a suction port formed in the apparatus main body, and a ventilation duct for guiding outside air sucked by the cooling fan to a paper discharge unit. An exhaust port of the ventilation duct is opened immediately after the exit of the recording medium of the fixing unit. The aim of the image forming apparatus configured as described above is to efficiently cool the recording medium by blowing air from the exhaust port of the ventilation duct onto the recording medium immediately after fixing (returned into the apparatus main body when performing double-sided printing). Thus, even if the recording medium is a large size or an OHP sheet, the recording medium is sufficiently cooled to suppress an increase in temperature in the apparatus main body.

  However, the image forming apparatuses disclosed in Patent Documents 1 to 4 have the following problems.

  That is, in the image forming apparatus disclosed in Patent Document 1, the connection path and the recording medium passing through the connection path can be cooled by the cooling fan. However, it is not configured to cool both the upstream and downstream image forming units disposed in the apparatus main body. In particular, it can be said that the downstream image forming unit cannot be substantially cooled by the cooling fan. Further, since a duct that requires a large space is required in addition to the cooling fan as a cooling means for the connection path and the fixing device, the main body of the device is increased in size, the weight is increased, and the cost is increased.

  The image forming apparatus disclosed in Patent Document 2 can cool the recording medium discharged from the discharge port and the recording medium discharged to the tray, respectively. In addition, a configuration is also disclosed in which exhaust in the apparatus main body and air can be blown out to a plurality of trays by a single exhaust fan. However, since the exhaust fan is disposed outside the paper discharge passage, when the recording medium passes through the paper discharge passage continuously, the exhaust in the apparatus main body is substantially cut off and the heat fixing is performed. There is a high possibility that cooling of the recorded recording medium and exhausting of the apparatus main body will not be performed as desired. As a result, there is a possibility that the temperature of the recording medium and the temperature inside the apparatus body will rise excessively temporarily. In addition to the cooling fan, it requires multiple ducts to guide the air sucked by the cooling fan toward the multiple trays, making the structure of the device main body complicated and increasing the size of the device main body. In addition, the weight increases and the cost increases.

  In the image forming apparatus disclosed in Patent Document 3, since the cooling fan is disposed outside the conveyance path, air sucked from outside the apparatus main body is blown onto the recording medium passing through the conveyance path, and the recording medium Is cooled. However, it is unlikely that the heat exhausted from the apparatus main body is performed by the cooling fan. The reason is that there is no disclosure about exhaust of air introduced into the main body of the apparatus by the cooling fan, and this apparatus operates the cooling fan only on a specific recording medium such as an OHP sheet to cool the recording medium. For this reason, the cooling fan is not operated in image formation using plain paper. Further, if this cooling fan is used to cool the image forming unit in this image forming apparatus, the outside air sent by the cooling fan must pass through the vicinity of the fixing device. As a result, the air introduced into the apparatus main body by the cooling fan is heated by the fixing device, and the heated air is further heated inside, so that the temperature in the apparatus main body may be excessively increased. is there.

  In the image forming apparatus disclosed in Patent Document 4, the recording medium immediately after being thermally fixed can be cooled. However, a configuration in which the exhaust heat in the apparatus main body is performed is not disclosed. Further, since a dedicated ventilation duct for guiding the outside air sucked by the cooling fan to the paper discharge unit is required, the configuration becomes complicated, the weight increases, and the cost increases.

As is clear from the above description, the cooling means provided in the image forming apparatuses disclosed in Patent Documents 1 to 4 are mainly for cooling the heat-fixed recording medium, and the exhaust heat in the apparatus main body. In particular, cooling of the image forming means disposed in the apparatus main body is not considered.
JP 2000-296934 A JP 2002-072729 A JP 2002-31758 A JP 2002-333814 A

  An object of the present invention is to efficiently and effectively cool the inside of an image forming apparatus main body, particularly the periphery of an image forming unit, and a recording medium thermally fixed by a fixing apparatus, with a simple and inexpensive configuration. A novel image forming apparatus that can be used.

According to the present invention, an image forming unit that forms a toner image by electrophotography and transfers the toner image to a recording medium, a fixing unit that thermally fixes the toner image to the recording medium, and a recording medium on which the toner image is thermally fixed are discharged. In the image forming apparatus, a discharge conveyance path for conveying to the section is disposed in the apparatus main body, and the discharge conveyance path extends in the vertical direction along one side wall of the apparatus main body.
Between the image forming unit and the discharge conveyance path, at least one cooling fan that generates an air flow from the image forming unit side to the discharge conveyance path is disposed on the inner side facing the discharge conveyance path. An exhaust port is formed in each of the discharge conveyance path facing the fan and the one side wall.
An image forming apparatus is provided.
The cooling fan is disposed horizontally with respect to the image forming unit. When the cooling fan is operated, the air sucked into the apparatus body from the outside passes through the periphery of the image forming unit and is discharged. It is preferable to be sprayed on the conveyance path.
The image forming means includes a plurality of process units arranged substantially in parallel in the axial direction of the cooling fan. When the cooling fan is operated, the air sucked into the inside from the outside of the apparatus main body is supplied to each of the process units. It is preferable that it is sprayed to the discharge conveyance path through the periphery.
The fixing unit is disposed below the cooling fan so as to extend in a horizontal direction perpendicular to the axial direction of the cooling fan. Between the fixing unit, the cooling fan, and the image forming unit, the fixing unit, the cooling fan, and the image are arranged. A partition wall that substantially partitions the forming unit is disposed so as to extend in a horizontal direction orthogonal to the axial direction, and the air from the image forming unit side toward the discharge conveyance path passes above the partition wall. It is preferable.
It is preferable that an inclined gap is formed between the partition wall and the image forming unit so that air flows upward from the lower side of the image forming unit toward the cooling fan.
The apparatus main body has two other side walls that are spaced apart from each other in the horizontal direction perpendicular to the axial direction of the cooling fan, and vent holes are formed in one and / or both of the other two side walls. The vent is preferably disposed in a region extending from the lower side to the upper side of the partition wall on the extension of the partition wall on one and / or both of the other two side walls.
On the inside of the vent formed on one of the other two side walls, on the extension of the inner region of the partition wall, an air flow is generated from the inside of the apparatus body to the outside through the vent. It is preferable that a cooling fan for cooling the fixing unit is provided.
Another vent is formed at the upper end of one of the other two side walls and in the vicinity of the other side wall facing the one side wall, and inside the other vent is a device. It is preferable that a cooling fan is provided for sucking air from the outside of the main body to the inside through the other vent hole.
The apparatus main body has a front side wall located on the front side of the apparatus main body, a rear side wall opposed to the front side wall with a space behind, a right side wall located on the right side of the apparatus main body, and a left side spacing with respect to the right side wall. It is preferable that four side walls including a left side wall facing each other and an upper cover that covers the four side walls from above are provided, and the one side wall includes the rear side wall.
The upper cover includes the paper discharge portion that is inclined downward from the front side to the rear side of the apparatus main body toward directly above the cooling fan, and the top of the image forming unit is located directly below the lower surface of the paper discharge portion. When the cooling fan is operated with a gap therebetween, the air that is heated and rises inside the apparatus main body passes through the gap between the top of the image forming means and the lower surface of the paper discharge unit, and It is preferable that it is made to flow toward the cooling fan along the lower surface.

  Hereinafter, a tandem color image forming apparatus which is an embodiment of an image forming apparatus configured according to the present invention will be described in detail with reference to the accompanying drawings.

  Referring to FIGS. 1 to 5, a tandem type color image forming apparatus (more specifically, a tandem type color printer) denoted as a whole by reference numeral 100 includes an apparatus body 2 having a substantially rectangular parallelepiped shape. The apparatus main body 2 has four side walls, that is, a front side wall 4 located on the front side (right side in FIGS. 4 and 5) of the apparatus main body 2, and a rear side (left side in FIGS. 4 and 5) with respect to the front side wall 4. The rear side wall 6 that is opposed to each other, the right side wall 8 that is located on the right side (upper side in FIG. 5) of the apparatus main body 2, and the left side of the apparatus main body 2 (lower side in FIG. And the left side wall 10 facing each other. At the upper end of the front side wall 4 located on the front side of the apparatus main body 2 facing the user, an inclined part 4a that is inclined upward toward the rear of the apparatus main body 2 is disposed, and various operation buttons are provided on the inclined part 4a. It is arranged. The upper surface of the apparatus main body 2 is covered with a paper discharge tray 12 formed integrally with the upper cover. The paper discharge tray 12 constituting the recording medium discharge portion is inclined downward from the front side to the rear side of the apparatus main body 2. A substantially rectangular opening 14 is formed in the rear side wall 6, and a substantially rectangular rear cover 16 that opens and closes the opening 14 is mounted. It can be said that the rear cover 16 constitutes a part of the rear side wall 6 with the opening 14 closed (the state shown in FIG. 1).

  4 and 5, in the apparatus main body 2, a yellow process unit 20, a magenta process unit 22, a cyan process unit 24, and a black process unit 26 are arranged from left to right in FIG. Are arranged in this order. Each of these process units 20, 22, 24, and 26 includes image forming elements such as a photosensitive drum 30, a charger 31, an LED head 32, a developing device 33, a primary transfer roller 34, and a cleaning device 35. In FIG. 4, for simplification of illustration, the reference numerals of the image forming elements are attached only to the black process unit 26. These process units 20, 22, 24, and 26 are arranged in the above order in a substantially horizontal direction, in the embodiment, in a substantially straight line from left to right upward in FIG.

  To the developing devices 33 of the process units 20, 22, 24, and 26, toner replenishing containers 33Y, 33M, 33C, and 33B for replenishing the corresponding color toners are mounted, respectively. An intermediate transfer belt mechanism 36 is disposed below the process units 20, 22, 24 and 26. The intermediate transfer belt mechanism 36 includes a driving roller 38, driven rollers 40 and 42, and an intermediate transfer belt 44 wound around these rollers. The driven roller 40 is disposed on the left side in the apparatus main body 2 in FIG. 4, and the driving roller 38 is disposed on the right side in FIG. The driving roller 38 is located slightly higher than the driven roller 40. The driven roller 42 is disposed obliquely downward to the right in FIG. 4 with respect to the driven roller 40. A cleaning device 45 for cleaning the intermediate transfer belt 44 is disposed adjacent to the left end of the intermediate transfer belt mechanism 36 in FIG.

  The upper end travel region of the intermediate transfer belt 44 extending linearly between the drive roller 38 and the driven roller 40 is positioned so as to be slightly inclined upward with respect to the horizontal line from left to right in FIG. In each of the process units 20, 22, 24 and 26, the primary transfer roller 34 is brought into pressure contact with the photosensitive drum 30 from below via the upper end travel region of the intermediate transfer belt 44. A secondary transfer roller 46 is disposed below the driven roller 42, and the secondary transfer roller 46 is pressed against the driven roller 42 from below via an intermediate transfer belt 44. Since the drive roller 38 is driven to rotate clockwise in FIG. 4, the intermediate transfer belt 44 and the driven rollers 42 and 44 are also rotated clockwise. Since each of the primary transfer rollers 34 is disposed on the intermediate transfer belt mechanism 36 side, the apparatus is not integrally provided in each of the process units 20, 22, 24 and 26. Here, each of the process units 20, 22, 24 and 26 is included as a transfer function. Each of the process units 20, 22, 24 and 26, the intermediate transfer belt mechanism 36, the secondary transfer roller 46, and the cleaning device 45 constitute an image forming unit 100 </ b> A in the image forming apparatus 100.

  The top of the image forming unit 100A, in the embodiment, the tops of the toner supply containers 33Y, 33M, 33C, and 33B of the process units 20, 22, 24, and 26 are inclined downward from the front side to the rear side of the apparatus main body 2. It is arranged with a gap directly below the lower surface of the paper discharge tray 12, which is a paper discharge section.

  Below the intermediate transfer belt mechanism 36, a conveyance path 48 for conveying a recording medium, generally plain paper P, extends substantially in the horizontal direction in FIG. A nip portion between the secondary transfer roller 46 and the driven roller 42 is disposed in the middle of the conveyance path 48. A paper feed cassette 50 is disposed below the conveyance path 48. A pickup roller 52 is disposed just above the right end of the sheet feeding cassette 50 in FIG. 4, and a separation roller pair 54 is disposed downstream of the pickup roller 52. The downstream side of the separation roller pair 54 is connected to the conveyance path 48 via the reverse path 56. A registration roller pair 58 is disposed upstream of the secondary transfer roller 46 in the conveyance path 48. On the downstream side of the secondary transfer roller 46 in the conveyance path 48, a fixing unit 60 and a conveyance roller pair 62 are arranged in this order toward the downstream side. The fixing unit 60 includes a fixing roller pair 63. The fixing roller pair 63 is disposed so as to extend between the right side wall 8 and the left side wall 10 (so as to extend in a direction perpendicular to the paper surface in FIG. 4).

  A discharge conveyance path 64 for conveying the recording medium on which the toner image is thermally fixed by the fixing unit 60 to the sheet discharge tray 12 is disposed on the downstream side of the conveyance roller pair 62. The discharge conveyance path 64 is disposed inside the rear cover 16 so as to extend in the vertical direction along the rear cover 16 constituting a part of the rear side wall 6 which is one side wall of the apparatus main body 2. A pair of conveyance rollers 66 is disposed in the middle of the discharge conveyance path 64, and a pair of discharge rollers 68 is disposed at the outlet of the discharge conveyance path 64. The discharge conveyance path 64 is disposed on the inner wall 70 disposed so as to face the plurality of ribs 16R disposed on the inner side of the rear cover 16 and the inner side of the rear side wall 6 in the apparatus main body 2 with a space therebetween. The plurality of ribs 70R. The plurality of ribs 70 </ b> R disposed on the inner wall 70 are disposed to face the ribs 16 </ b> R of the rear cover 16 with a gap therebetween (with the rear cover 16 closed). The ribs 16R of the rear cover 16 and the ribs 70R of the inner side wall 70 are arranged so as to extend in the vertical direction at intervals in a direction perpendicular to the paper surface in FIG.

  In the image forming unit 100A, in the embodiment, in the space between the process unit 20 and the discharge conveyance path 64 in the image forming unit 100A, an air flow from the image forming unit 100A side toward the discharge conveyance path 64 (see arrows in FIG. 4). At least one cooling fan (in the embodiment, two cooling fans 72) is disposed on the inner side facing the discharge conveyance path 64. More specifically, on the inner side wall 70, two cylindrical cases 72C extending further inward from the inner side wall 70 are disposed at intervals in a direction perpendicular to the paper surface in FIG. . A cooling fan 72 is rotatably disposed in each case 72C. Each of the case 72C and the axis of the cooling fan 72 extend horizontally in parallel in the left-right direction (the front-rear direction of the apparatus main body 2) in FIGS.

  A plurality of exhaust ports 74 are formed in the discharge conveyance path 64 facing each of the cooling fans 72. Each of the exhaust ports 74 is formed at a position of the inner wall 70 corresponding to each of the cases 72C (and thus a position corresponding to each of the cooling fans 72), and is opened between the ribs 70R formed on the inner wall 70. is doing. A plurality of exhaust ports 76 extend in a direction perpendicular to the ribs 16R at intervals in the vertical direction at positions corresponding to the respective cases 72C of the rear cover 16 (and therefore positions corresponding to the respective cooling fans 72). It is formed to exist. Each of the exhaust ports 76 opens between the ribs 16 </ b> R formed in the rear cover 16.

  The fixing unit 60 is disposed below each cooling fan 72 so as to extend in a horizontal direction perpendicular to the axial direction of each cooling fan 72. Between each of the cooling fans 72 and the fixing unit 60, a partition wall 78 that substantially partitions the fixing unit 60 with respect to the air flow generated by each of the cooling fans 72 is disposed. The partition wall 78 is disposed so as to extend in the horizontal direction perpendicular to the axial direction of each cooling fan 72. The partition wall 78 has a horizontal top portion having a constant lateral width in FIG. 4. The left end of the horizontal top portion in FIG. 4 is connected to the inner wall 70, and the right end is connected to the process unit 20 and the fixing means 60. It is connected to the upper end of the side portion that extends downwardly inclined toward the transport path 48 and then hangs down toward the transport path 48. An inclined gap 79 is formed between the partition wall 78 and the image forming unit 100A, in the embodiment, the process unit 20 so that air flows upward from the lower side of the process unit 20 toward the cooling fan 72. Yes,

  The apparatus main body 2 includes the right side wall 8 and the left side wall 10 which are the other two side walls facing each other with a gap in the horizontal direction perpendicular to the axial direction of each cooling fan 72. A plurality of vent holes 80 are formed in one or both of the right side wall 8 and the left side wall 10, or both in the embodiment (see FIGS. 1 to 3). Each of the vent holes 80 formed in both the right side wall 8 and the left side wall 10 is in an area extending from the lower side to the upper side of the partition wall 78 on the extension of the partition wall 78 in both the right side wall 8 and the left side wall 10. It is arranged. On the inner side of each of the vent holes 80 formed in the right wall 8 and on the extension of the lower region of the partition wall 78, an air flow is generated from the inside of the apparatus main body 2 to the outside through each of the vent holes 80. Then, a cooling fan 61 for cooling the fixing unit 60 is provided (indicated by a dotted line in FIG. 5).

  A plurality of other vent holes 82 are formed at the upper end of the right side wall 8 and in the vicinity of the front side wall 4, which is another side wall facing the rear side wall 6 (see FIGS. 1 and 2). ). A cooling fan 84 for sucking air from the outside of the apparatus main body 2 to the inside through the ventilation hole 82 is disposed inside the ventilation hole 82 (shown by a dotted line in FIG. 5).

  In the image forming apparatus 100, the printing operation itself is performed as is well known, and will be briefly described below.

  Referring to FIG. 4, when printing is performed, the surface of the photosensitive drum 30 uniformly charged by the charger 31 is exposed by the LED head 32 in each of the process units 20, 22, 24 and 26. Thus, an electrostatic latent image is formed, and this electrostatic latent image is developed by the developing device 33 to become a toner image. The toner images are sequentially superimposed and transferred from the toner images formed by the upstream process unit 20 onto the intermediate transfer belt 44 of the intermediate transfer belt mechanism 36 by the primary transfer roller 34. The color toner image transferred to the intermediate transfer belt 44 is transferred to the plain paper P while the plain paper P sent from the paper feed cassette 50 passes through the nip portion between the driven roller 42 and the secondary transfer roller 46. The The toner image transferred to the plain paper P is thermally fixed to the plain paper P while passing through the fixing means 60. The plain paper P on which the toner image is thermally fixed is conveyed through the discharge conveyance path 64 by the conveyance roller pairs 62 and 66 and is discharged onto the paper discharge tray 12 by the discharge roller pair 68. In the process units 20, 22, 24 and 26, the toner that is not transferred and remains on the surface of the photosensitive drum 30 is cleaned by the cleaning device 35. If the toner remains on the intermediate transfer belt 44, the toner is cleaned by a cleaning device 45 for the intermediate transfer belt 44 disposed at a position facing the driven roller 40 with the intermediate transfer belt 44 interposed therebetween.

  4 and 5, in the image forming apparatus 100, when each of the cooling fans 72 is driven to rotate, air is supplied from the inside of the apparatus body 2 in each of the cooling fans 72 (FIGS. 4 and 5). In FIG. 4 and FIG. 5, the substantially horizontal air flow from the right side of each cooling fan 72 toward the discharge conveyance path 64 and the rear cover 16 (toward the left side of each cooling fan 72 in FIG. 4 and FIG. 5). Is generated. As a result, air is sucked into the apparatus main body 2 from the outside, and the air sucked into the apparatus main body 2 passes through the periphery of each of the process units 26, 24, 22, and 20 by each of the cooling fans 72. The gas is blown to the discharge conveyance path 64 through each of the exhaust ports 74. At this time, when the printing operation is not performed, the air blown to the discharge conveyance path 64 is exhausted to the outside of the apparatus main body 2 through each of the exhaust ports 76 of the rear cover 16. The arrows in FIGS. 4 and 5 indicate such air flow.

  As described above, the air sucked into the inside of the apparatus main body 2 passes through the periphery of each of the process units 26, 24, 22 and 20, and is exhausted to the outside of the apparatus main body 2 by each of the cooling fans 72. One LED head 32 is provided for each of the units 26, 24, 22 and 20, and similarly, one photosensitive drum 30 is provided for each of the process units 26, 24, 22 and 20. The internal air of the apparatus main body 2 raised in temperature by a driving electric motor or the like is forcibly exhausted without staying. As a result, the inside of the apparatus main body 2, in particular, the periphery of each of the process units 26, 24, 22, and 20 is effectively cooled, so that the toner in the developing device 33 and the toner collected in the cleaning device 35 are solidified. Failure to do so is prevented.

  In addition, air can be sucked from the outside to the inside of the apparatus main body 2 by using the gaps existing in each of the front side wall 4, the right side wall 8, and the left side wall 10. As a result, since it is not necessary to use a duct for sucking air from the outside of the apparatus main body 2, the configuration is simplified, the apparatus main body 2 can be reduced in weight and size, and the cost can be reduced. .

  As described above, each of the cooling fans 72 is rotationally driven to cool each of the process units 26, 24, 22, and 20 with the air sucked into the apparatus body 2 from the outside, and each of the cooling fans 72 When a printing operation is performed in a state where air is blown onto the discharge conveyance path 64, air is blown onto the plain paper P on which the toner image is thermally fixed by the fixing unit 60, which passes through the discharge conveyance path 64. . Since the plain paper P on which the toner image has been heat-fixed is sufficiently cooled, the problem of sticking to the other plain paper P when it is discharged to the discharge tray 12 is prevented, and the plain paper P is removed from the discharge tray 12. It is also possible to prevent the problem that the plain paper P is hot and difficult to take out when taking it out of the paper. As described above, according to the present invention, each of the cooling fans 72 can simultaneously cool the inside of the apparatus main body 2 and the plain paper P on which the toner image is thermally fixed, so that efficient and effective cooling can be achieved. It becomes possible.

  The plain paper P on which the color image is fixed is easily curled. In particular, when an image with a high printing rate close to four colors is fixed, it is very easy to curl. According to the present invention, the toner is cooled by each of the cooling fans 72 immediately after the toner is thermally fixed by the fixing means 60, so that the curling is effectively prevented.

  Since the process units 26, 24, 22 and 20 are arranged in parallel in the axial direction of each cooling fan 72 inside the apparatus body 2, in other words, the air flow generated by each cooling fan 72 is Since they are arranged in parallel in the direction (substantially horizontal in FIG. 4), it is possible to easily exhaust the high-temperature air around the process units 26, 24, 22 and 20 efficiently.

  The upper cover includes a paper discharge portion that inclines downward from the front side to the rear side of the apparatus body 2 toward directly above each of the cooling fans 72, and in the embodiment, includes a paper discharge tray 12. The top of the image forming unit 100 </ b> A is disposed with a gap immediately below the lower surface of the paper discharge tray 12. When each of the cooling fans 72 is operated, the air heated and raised by the LED head 32 or the like inside the apparatus main body 2 passes through the gap between the top of the image forming unit 100A and the lower surface of the paper discharge tray 12, and is discharged. It is made to flow toward each of the cooling fans 72 along the lower surface of the paper tray 12. Such a configuration makes it possible to collect and exhaust the air heated and raised inside the apparatus main body 2 to the cooling fan 72 efficiently without requiring a special duct and without cost.

  The fixing unit 60 is disposed below the cooling fan 72 so as to extend in a horizontal direction perpendicular to the axial direction of the cooling fan 72. The fixing unit 60, each of the cooling fan 72, each of the image forming unit 100A, and the process unit 20 in the embodiment are substantially connected to the fixing unit 60, each of the cooling fan 72, and the process unit 20. A partition wall 78 is provided so as to extend in a horizontal direction perpendicular to the axial direction. Air that is generated by the rotation of each cooling fan 72 and travels from the image forming unit 100 </ b> A side toward the discharge conveyance path 64 passes above the partition wall 78, and is thus blown onto the plain paper P that passes through the discharge conveyance path 64. The air heated by the fixing means 60 is sucked into the air thus generated, and the cooling effect of the plain paper P is not impaired. Further, the temperature of the image forming unit 100A does not rise due to the heat of the fixing unit 60.

  An inclined gap 79 is formed between the partition wall 78 and the image forming unit 100 </ b> A, in the embodiment, the process unit 20 so that air flows upward from the lower side of the process unit 20 toward each of the cooling fans 72. Has been. This configuration effectively discharges air that is warmed up by the apparatus main body 2 and contributes to cooling of the inside of the apparatus main body 2.

  Each of the cooling fans 72 is disposed between the image forming unit 100 </ b> A, in the embodiment, the process unit 20 and the discharge conveyance path 64, that is, inside the discharge conveyance path 64, and thus passes through the discharge conveyance path 64. When air is blown onto the plain paper P, the air is blocked from flowing on the plain paper P, and thus is directed to the right side wall 8 and the left side wall 10. When the partition wall 78 is provided, the air flows along the upper surface of the partition wall 78 toward the right side wall 8 and the left side wall 10, respectively. A plurality of vent holes 80 are formed in the right side wall 8 and the left side wall 10 respectively. The vent 80 is arranged in a region extending from the lower side to the upper side of the partition wall 78 on the extension of the partition wall in the right side wall 8 and the left side wall 10. It is possible to exhaust to the outside. The air is not only from the vent hole 80, but also from the right side wall 8 and the gap between the left side wall 10 and the rear side wall 6 and the discharge opening for discharging the plain paper P with the image fixed on the paper discharge tray 12. Since it is discharged to the outside of the apparatus main body 2, the inside of the apparatus main body 2 can be cooled more effectively.

  As described above, the cooling fan 61 for cooling the fixing unit 60 is arranged on the inner side of each of the vent holes 80 formed in the right side wall 8 and on the extension of the inner region of the partition wall 78. It is installed. During the printing operation, the cooling fan 61 is driven to rotate, so that external air is sucked into the apparatus main body 2 from each of the vent holes 80 on the left side wall 10. The air sucked into the apparatus main body 2 passes through the periphery of the fixing means 60 located inside the partition wall 78 and is exhausted to the outside from each of the vent holes 80 on the right side wall 8 by the cooling fan. Therefore, as described above, the air flow blocked by the plain paper P and directed to the right side wall 8 and the left side wall 10 outside the partition wall 78 eventually cools the fixing unit 60. Therefore, the air generated by the cooling fan 61 is discharged from each of the vent holes 80 separately (because it is partitioned by the partition wall 78). The heat of the fixing unit 60 is blocked by the partition wall 78 so as not to be directed to the image forming unit 100A side, which contributes to prevention of temperature rise inside the apparatus main body 2.

  As described above, a plurality of other vent holes 82 are formed at the upper end portion of the right side wall 8 and in the vicinity of the front side wall 4. A cooling fan 84 (FIG. 5) for sucking air from the outside of the apparatus main body 2 to the inside through the other vent hole 82 is disposed inside the other vent hole 82. Although not shown in the drawing, both ends of the process units 20, 22, 24 and 26 in the longitudinal direction (vertical direction in FIG. 5) are supported by the right and left plates disposed in the apparatus main body 2. Has been. The right side plate and the left side plate are arranged with a gap inside the right side wall 8 and the left side wall 10, respectively. An electric board is attached to the outside of the right side plate with a gap, and four electric motors for driving a rotating body such as a photosensitive drum in each of the process units 20, 22, 24 and 26 are attached to the electric board. It has been. A plurality of vents are formed at the upper position of the right side plate.

  When the cooling fan 84 is driven to rotate, the air sucked from the outside of the apparatus main body 2 through the other vent 82 passes through the gap between the electrical board that functions as a duct and the right side plate, The air is discharged from the vent 80 to the outside. The air motor cools the electric motor. A part of the air sucked between the right side plate and the electrical board by the cooling fan 84 is blown out to the image forming unit 100A side from a plurality of vent holes formed in the right side plate. Since this air is warmed by the cooling of the electric motor, an updraft is generated in the vicinity of each of the process units 20, 22, 24 and 26. Ascending air is also generated around each of the process units 20, 22, 24 and 26 in the form of being dragged by the ascending air, and these air currents are sucked by the cooling fan 72, and as described above, the apparatus main body. 2 is discharged to the outside.

  As the cooling fans 61, 72, and 84 rotate, a considerable amount of noise is generated. In the image forming apparatus 100, each of the cooling fans 72 is disposed inside the discharge conveyance path 64 disposed inside the rear side wall 6 farthest from the front side wall 4 that the user faces. This contributes to a reduction in discomfort given to the user.

  Generally, in a monochrome image forming apparatus, since there is a considerable gap around the image forming unit, there is no need to intentionally cool the LED head, and the air flow generated in the apparatus main body by the cooling fan of the fixing unit. It can be cooled sufficiently. However, the illustrated tandem color image forming apparatus is the same size as that of the monochrome image forming apparatus (that is, is small in size), and the process units for four colors are arranged in the apparatus main body. If the heat generated from the LED head is not forcibly discharged to the outside, the inside of the apparatus body becomes very hot. In particular, in color image forming apparatuses, there are many images that are close to solid images such as photographs compared to monochrome image forming apparatuses, and the LED element lighting time is correspondingly longer, so the LED head is used in a monochrome image forming apparatus. The temperature tends to be higher. There is a danger that the LED head will break down when the temperature is high, and color misregistration may occur when the LED head warps. In addition, heat generated from the electric motor that drives the photosensitive drum or the like is transmitted to the photosensitive drum or the like, which may cause a problem. According to the present invention, these problems can be solved with a simple and inexpensive configuration.

  The present invention is applied to a tandem type color image forming apparatus, but is also applicable to other forms of color image forming apparatuses or monochrome image forming apparatuses. As another form of color image forming apparatus, for example, a color image forming apparatus using three color toners, or toners of different colors are sequentially superimposed and transferred directly onto a transported recording medium. Color image forming apparatus in the form. In the above embodiment of the present invention, two cooling fans 72 are provided, but the number of the cooling fans 72 may be appropriately determined according to various conditions such as the size of the image forming apparatus. Needless to say, the numbers of the exhaust ports 74 and 76 and the vent holes 80 are also set as appropriate.

1 is a perspective view of a tandem color image forming apparatus that is an embodiment of an image forming apparatus configured according to the present invention. FIG. 2 is a perspective view showing the image forming apparatus shown in FIG. 1 with a rear cover opened. FIG. 2 is a rear view showing the image forming apparatus shown in FIG. 1 with a rear cover removed. It is sectional drawing of the image forming apparatus shown in FIG. FIG. 2 is a plan view showing the image forming apparatus shown in FIG. 1 with an upper cover removed.

Explanation of symbols

2: Image forming apparatus body 4: Front side wall 6: Rear side wall 8: Right side wall 10: Left side wall 12: Paper discharge tray (paper discharge unit)
20, 22, 24, 26: Process unit 60: Fixing means 61, 72, 84: Cooling fan 64: Discharge conveyance path 74, 76: Exhaust port 78: Partition wall 80, 82: Vent 100: Image forming apparatus 100A: Image forming means

Claims (10)

Image forming means for forming a toner image by electrophotography and transferring it to a recording medium, fixing means for thermally fixing the toner image to the recording medium, and conveying the recording medium on which the toner image is thermally fixed to a discharge section In the image forming apparatus, the discharge conveyance path is disposed in the apparatus main body, and the discharge conveyance path extends in the vertical direction along one side wall of the apparatus main body.
Between the image forming unit and the discharge conveyance path, at least one cooling fan that generates an air flow from the image forming unit side to the discharge conveyance path is disposed on the inner side facing the discharge conveyance path. An exhaust port is formed in each of the discharge conveyance path facing the fan and the one side wall.
An image forming apparatus.   The cooling fan is disposed horizontally with respect to the image forming unit. When the cooling fan is operated, the air sucked into the apparatus body from the outside passes through the periphery of the image forming unit and is discharged. The image forming apparatus according to claim 1, wherein the image forming apparatus is sprayed on a conveyance path.   The image forming means includes a plurality of process units arranged substantially in parallel in the axial direction of the cooling fan. When the cooling fan is operated, the air sucked into the inside from the outside of the apparatus main body is supplied to each of the process units. The image forming apparatus according to claim 2, wherein the image forming apparatus is blown through the periphery to the discharge conveyance path.   The fixing unit is disposed below the cooling fan so as to extend in a horizontal direction perpendicular to the axial direction of the cooling fan. Between the fixing unit, the cooling fan, and the image forming unit, the fixing unit, the cooling fan, and the image are arranged. A partition wall that substantially partitions the forming unit is disposed so as to extend in a horizontal direction orthogonal to the axial direction, and the air from the image forming unit side toward the discharge conveyance path passes above the partition wall. The image forming apparatus according to claim 1.   The image forming apparatus according to claim 4, wherein an inclined gap is formed between the partition wall and the image forming unit so that air flows upward from below the image forming unit toward the cooling fan.   The apparatus main body has two other side walls that are spaced apart from each other in the horizontal direction perpendicular to the axial direction of the cooling fan, and vent holes are formed in one and / or both of the other two side walls. The vent is disposed in a region extending from the lower side to the upper side of the partition wall on the extension of the partition wall on one and / or both of the other two side walls. The image forming apparatus described.   On the inside of the vent formed on one of the other two side walls, on the extension of the inner region of the partition wall, an air flow is generated from the inside of the apparatus body to the outside through the vent. The image forming apparatus according to claim 6, further comprising a cooling fan for cooling the fixing unit.   Another vent is formed at the upper end of one of the other two side walls and in the vicinity of the other side wall facing the one side wall, and inside the other vent is a device. The image forming apparatus according to claim 7, wherein a cooling fan is provided for sucking air into the inside from the outside of the main body through the other vent hole.   The apparatus main body has a front side wall located on the front side of the apparatus main body, a rear side wall opposed to the front side wall with a space behind, a right side wall located on the right side of the apparatus main body, and a left side spacing with respect to the right side wall. 9. The apparatus according to claim 1, further comprising: an upper cover that covers the four side walls from above, and the one side wall includes the rear side wall. Image forming apparatus.   The upper cover includes the paper discharge portion that is inclined downward from the front side to the rear side of the apparatus main body toward directly above the cooling fan, and the top of the image forming unit is located directly below the lower surface of the paper discharge portion. When the cooling fan is operated with a gap therebetween, the air that is heated and rises inside the apparatus main body passes through the gap between the top of the image forming means and the lower surface of the paper discharge unit, and The image forming apparatus according to claim 9, wherein the image forming apparatus is caused to flow toward the cooling fan along the lower surface.

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