JP2007078765A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus that prevents a decrease in cooling efficiency in a part to be cooled and does not lose silence. <P>SOLUTION: The image forming apparatus 10 includes an air suction part 30 which sucks air into a apparatus main body 111, an air discharge part 40 which discharges the air introduced into the apparatus main body 111 through the air suction part 30, and the part 51 to be cooled which is arranged between the air suction part 30 and air discharge part 40 in the apparatus main body 111, and the air suction part 30 includes an air intake 31 provided correspondingly to the part 51 and two air blowing fans 331 to 322 blowing the air sucked from the air intake 31 to the part 51. The air blowing fans 331 and 332 are arranged in series in the air flow direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

  Conventionally, in image forming apparatuses such as copying machines, facsimiles, printers, etc., there are heat generating parts (for example, a charging device, a fixing device, a developing device, etc.), and the inside of the apparatus body exceeds a predetermined temperature due to the heat generated by these heat generating parts. As shown in FIG. 6, air outside the apparatus is sucked in by a fan 103 provided in front of a heat source (for example, a developing unit) 102 arranged in the air flow path 101. The cooling process is performed by forming an air flow that flows through the inside of the apparatus (see Patent Document 1).

However, as shown in FIG. 7 or FIG. 8, a heat source (for example, a motor for driving a cleaning member of the charging device) 104 having a small heat generation amount is located outside the air flow path 101 and in the vicinity of the fan 103. When added, since the cooling air is also blown to the heat source 104, as shown in FIG. 7, the fan is enlarged so that the fan 105 extends over the two heat sources 102 and 104 on the upstream side. 8, or by adding a fan 106 equivalent to the fan 103 in front of the heat source 104, that is, increasing the number of fans in parallel, as shown in FIG.
JP 2003-76253 A

  However, as shown in FIG. 7, when one fan is increased in size, there is a problem that cooling efficiency is lowered. That is, if the fan air volume (the number of revolutions) is set in accordance with the heat source 102 having a large heat generation amount, the air volume is too large for the heat source 104 having a small heat generation amount. If the fan air volume (number of rotations) is set in accordance with the heat source 104 having a small heat generation amount, the heat source 104 having a large heat generation amount has a shortage of air volume, and the entire heat source cannot be sufficiently cooled.

  Further, as shown in FIG. 8, simply increasing the number of fans in parallel can increase the speed of the image forming apparatus, and if the heat generation amount of the heat source 102 is further increased due to the increase in the speed of the image forming apparatus, There is a problem in that the number of rotations of 106 must be increased, and noise such as fan motor driving noise and fan wind noise increases, which impairs the quietness of the image forming apparatus.

  The present invention has been made in view of the above problems, and an object thereof is to provide an image forming apparatus that prevents the cooling efficiency of a portion to be cooled from being lowered and that the quietness is not impaired.

  In order to achieve the above-described object, the present invention provides an intake section that sucks air into the apparatus main body, an exhaust section that exhausts air introduced into the apparatus main body through the intake section, and the intake air within the apparatus main body. In the image forming apparatus including the cooled portion disposed between the cooling portion and the exhaust portion, the intake portion includes an intake port provided corresponding to the cooled portion, and air sucked from the intake port And a plurality of blower fans for blowing air to the cooled portion, wherein the plurality of blower fans are arranged in series in the air flow direction.

  The plurality of blower fans are composed of two fans, a large fan and a small fan, the large fan is on the upstream side in the air flow direction, the small fan is on the downstream side in the air flow direction, and the large fan and the small fan By arranging the fan shafts with different axes, outside air can be efficiently introduced by a large fan, and while cooling the surrounding area, air can flow toward the place where cooling is most necessary, Since air does not flow through unnecessary portions and there is no need to increase the size of the small fan, the cost can be minimized.

  According to the present invention, since the plurality of blower fans are arranged in series with respect to the air flow direction, the amount of air passing through the air flow path is increased, and the cooled portion can be efficiently cooled. Further, since it is not necessary to increase the rotational speed of each fan in order to increase the fan air volume, noise such as fan motor drive noise and fan wind noise is suppressed, and the quietness of the image forming apparatus is impaired. There is nothing.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is an external perspective view showing an embodiment of an image forming apparatus according to the present invention, and FIG. 2 is an explanatory diagram in front sectional view for explaining the internal structure. In the present embodiment, as an image forming apparatus according to the present invention, a multifunction machine having functions such as a copy function, a printer function, a scanner function, and a facsimile function will be described as an example. The apparatus is not limited to such a multifunction machine, and can be applied to a single-function machine such as a copying machine, a printer apparatus, a facsimile apparatus, or a scanner apparatus.

  The multifunction machine 11 includes a rectangular parallelepiped apparatus main body 111 in which various devices for image formation described later are mounted, and a document reading apparatus 119 attached to the upper part of the apparatus main body 111.

  The apparatus main body 111 is provided with a power switch 111a at an appropriate position on the side surface and an operation panel 111b at an appropriate position on the upper surface (the front side of the document reading device 119). The operation panel 111b includes an image forming process. Are provided, a start button 111c for starting the operation, a numeric keypad 111d for inputting the number of sheets P to be processed, a monitor screen 111e made of liquid crystal for outputting various comments, and the like.

  In the apparatus main body 111, as shown in FIG. 2, a paper feeding unit 112 disposed in a lower portion thereof, a paper transport unit 113 disposed on the side and above the paper feeding unit 112, and An image forming unit 114 disposed above the sheet feeding unit 112, a fixing device 115 disposed on the discharge side of the image forming unit 114, and above the image forming unit 114 and the fixing device 115. The image reading unit 116 is provided. The image forming unit 114 and the fixing device 115 are elongated in the width direction (direction perpendicular to the paper surface of FIG. 2) perpendicular to the sheet conveyance direction inside the apparatus main body 111, and in the upper part of the apparatus main body 111 in FIG. The image forming unit 114 and the fixing device 115 are arranged in this order from the right side along the conveyance direction (from right to left) of the paper P.

  The sheet feeding unit 112 feeds a bundle of sheets P stacked and loaded in the sheet feeding cassette 112a one by one from the uppermost sheet P to the sheet conveying unit 113 by rotating the sheet feeding roller. . The sheet conveying unit 113 conveys the sheet P fed from the sheet feeding unit 112 to the image forming unit 114 by various conveying roller pairs 113a, and further, the sheet on which the image is formed in the image forming unit 114 and the fixing device 115. P is discharged to a discharge tray via a pair of conveying rollers 113a provided on the downstream side of the fixing device 115.

  In double-sided printing, the paper P is conveyed again to the image forming unit 114 after the image transfer surface is reversed by the switchback unit 113b.

  The image reading unit 116 reads image information of a document. When reading each document by hand, the document reading device 119 is opened and a contact glass provided on the upper surface of the apparatus main body 111. When the original is placed on 116a and the original bundle is automatically read one by one, the original bundle is placed on the paper feed tray of the original reading device 119 in a closed state. It has become. When the original bundle is placed on the paper feed tray, the originals one by one from the original bundle are automatically fed sequentially onto the contact glass 116a. In any case, the original positioned on the contact glass 116a is irradiated with light from an exposure lamp, and the reflected light is guided to a photoelectric conversion unit including a CCD line sensor or the like via a reflecting mirror.

  The image forming unit 114 is disposed below the image reading unit 116 and forms a predetermined toner image on the paper P by an electrophotographic process. The image forming unit 114 has a photoconductive property that is rotatably supported by the shaft. A photosensitive drum 114a, a main charging device 114b disposed around the photosensitive drum 114a along the rotation direction, the exposure device 114c, the developing device 114d, and the sub-charging device 114h. The transfer device 114e, the cleaning device 114f, and the charge removal device 114g are provided.

  The fixing device 115 is disposed on the downstream side of the image forming unit 114 in the sheet conveying direction, and the sheet P on which the toner image has been transferred in the image forming unit 114 is formed by a pair of heating rollers 115a and a pressure roller 115b. The toner image is held between fixing rollers and heated to fix the toner image on the paper P to the paper P.

  Hereinafter, a basic operation of the multifunction machine 11 configured as described above will be described. First, the peripheral surface of the photosensitive drum 114a rotating in the clockwise direction in FIG. 2 is uniformly charged by the main charging device 114b, and subsequently the exposure device 114c (laser device) based on the image information read by the image reading unit 116. Etc.) is irradiated onto the peripheral surface of the photosensitive drum 114a, whereby an electrostatic latent image is formed on the peripheral surface of the photosensitive drum 114a. The electrostatic latent image is supplied with toner as a developer from the developing device 114d, and the peripheral surface of the photosensitive drum 114a is uniformly charged by the sub-charging device 114h, thereby forming a toner image.

  Subsequently, the paper P from the paper feeding unit 112 is conveyed toward the photosensitive drum 114a on which the toner image is formed through the paper conveying unit 113, where the photosensitive drum 114a is transferred by the transfer device 114e including a transfer roller or the like. Is transferred onto the paper P. Then, the sheet P on which the toner image is transferred is separated from the photosensitive drum 114a, conveyed to the fixing device 115, and the toner image is fixed by heat treatment by passing between the heating roller 115a and the pressure roller 115b. The The paper P that has passed through the fixing device 115 is discharged to the paper discharge tray 120 through the conveyance roller pair 113a.

  The photosensitive drum 114a after the transfer process of the toner image to the paper P is completed, the residual toner remaining on the peripheral surface is removed by the cleaning device 114f, and then the charge removal process is performed by the charge removal device 114g. After that, the peripheral charging surface is again charged by the main charging device 114b.

  In the image forming apparatus 10 configured as described above, the image forming unit 114, the fixing device 115, and the like generate heat by the image forming operation as described above. In particular, the heat from the fixing device 115 causes the inside of the apparatus main body 111 to be in a high temperature atmosphere. become. If this high temperature atmosphere is left as it is, there is a risk of adversely affecting the equipment in the apparatus. Therefore, in the present invention, the atmosphere in the apparatus main body 111 is replaced (specifically, outside air is introduced into the apparatus main body 111). Thus, the inside of the apparatus main body 111 is cooled.

  Hereinafter, a cooling structure for cooling the cooled portion 51 provided in the apparatus main body 111 of the multifunction machine 11 will be described with reference to FIGS. 1 and 2 as necessary based on FIGS. FIG. 3 is a perspective view of the multifunction machine 11 showing a state in which the front cover body (front cover) 117 is opened. FIG. 4 is an explanatory diagram of a cross-sectional side view of the multi-function device 11 as seen from a line crossing the developing device unit housing 61 in the longitudinal direction in order to explain the cooling structure. FIG. 5 is a partially enlarged view of FIG. 4 focusing on the periphery of the intake portion 30 in the cooling structure.

  As shown in FIG. 3, in the apparatus main body 111, a portion to be cooled 51 around a developing device 114d that forms a toner image by supplying toner to the peripheral surface of the photosensitive drum 114a on which an electrostatic latent image is formed. A portion to be cooled around the cleaning device 114f that removes residual toner remaining on the peripheral surface of the photosensitive drum 114a after the toner image is transferred to the paper P, and a fixing process for the toner image transferred to the paper P. The portions to be cooled are independently formed in three portions of the portion to be cooled 53 around the fixing device 115 that performs the above.

  The cooling structure of this embodiment is particularly characterized by the cooled portion 51 in the peripheral portion of the developing device 114d. This portion 51 to be cooled is configured as a developing device unit housing 61 in which a main charging device 114b and a sub charging device 114h are mounted.

  As shown in FIG. 4, the cooling structure is provided on the front side of the apparatus main body 111 and sucks air into the apparatus main body 111 and is introduced into the apparatus main body 111 through the intake section 30. An air exhaust unit 40 that exhausts air, and the air taken in from the air intake unit 30 circulates through the plurality of cooled parts 51 disposed between the air intake unit 30 and the air exhaust unit 40 in the apparatus main body 111. Then, after the cooled portion 51 is cooled, the exhausted portion 40 is exhausted to the outside.

  The intake portion 30 includes an intake port 31 provided corresponding to the cooled portion 51, a blower duct 32 provided corresponding to the intake port 31, and the cooled portion facing the blower duct 32. The 1st ventilation fan 331 and the 2nd ventilation fan 332 which were provided in 51 are provided. By driving the first and second blower fans 331 and 332, the air taken in through the air inlet 31 flows through the cooled part 51 and then exhausted through the exhaust part 40. ing.

  As shown in FIG. 1, the intake port 31 is provided at an upper position of a front cover body 117 that covers an upper front portion of the apparatus main body 111 so as to be freely opened and closed. A lattice-like louver 117 b is attached to the intake port 31.

  On the other hand, the front cover body 117 is formed in a double structure by a front plate 117 ′ and a back plate 117 ″ facing the front plate 117 ′ in a state of being slightly separated from the front plate 117 ′. The opening 31 is provided on the side of the front plate 117 '. The peripheral edge of the back plate 117 "is bent toward the front plate 117', and the annular edge formed is fixed to the front plate 117 'in a close contact state. Thus, the front plate 117 ′ and the back plate 117 ″ are integrated. The air passage space V through which the air taken in from the intake port 31 passes between the back plate 117 ′ and the back plate 117 ″. Is formed.

  The air passage space V communicates with the air inlet 31 and the air duct 32, and the air taken in from the air inlet 31 passes through the air passage space V to the cooled part 51 via the air duct 32. It has been introduced.

  As shown in FIG. 3, the front cover body 117 has a pair of upper and lower connections projecting in opposite directions from the upper and lower edges of one side (the right side in the example shown in FIG. 3). There are shafts 117a (the lower connecting shaft 117a is not shown), and these connecting shafts 117a are mounted on the right side above the paper feeding unit 112 of the apparatus main body 111, so that they rotate forward and backward around the connecting shaft 117a. It opens and closes by moving.

  As shown in FIGS. 3 to 5, the air duct 32 has a rectangular tube shape from the back plate 117 ″ of the front cover body 117, which has a double structure, into the apparatus main body 111, and the back plate 117. It protrudes in a state penetrating ″. The blower duct 32 has one end face facing the intake port 31 and the other end face facing the cooled portion 51.

  A lattice 324 (see FIG. 3) made of vertical and horizontal bars is formed on the other end surface of the air duct 32 (the end surface facing the portion 51 to be cooled), and the peripheral surface of the other end surface is respectively An annular seal member 325 made of an elastic member such as rubber or soft synthetic resin is attached.

  On the other hand, the developing device 114d is a unit in which related devices are grouped, and is housed in a developing device unit housing 61 (see FIG. 3). In addition to the developing device 114d, the developing device unit housing 61 is equipped with a main charging device 114b and a sub charging device 111h. In the present embodiment, the developing device unit housing 61 overlaps the cooled portion 51.

  The blower duct 32 can be in contact with the front surface of the developing device unit housing 61 via the annular seal member 325 in the state where the front cover body 117 is closed as follows. The projecting amount from ″ is set.

  A plurality of first ventilation holes 611 are formed in the wall surface of the developing device unit housing 61 facing the air duct 32. A plurality of second ventilation holes 612 are formed in a slightly recessed surface below the wall surface. For this reason, when the front cover body 117 is closed, as shown in FIG. 5, the air duct 32 comes into contact with the wall surface provided with the first ventilation hole 611 of the developing device unit housing 61. A gap 34 is formed between the second ventilation hole 612 and the back plate 117 ″ of the front cover body 117 without contacting the wall surface provided with the two ventilation holes 612.

  Two fans, a large first blower fan 331 and a small second blower fan 332, are provided in the front portion (right side in FIG. 5) in the developing device unit housing 61.

  These first and second blower fans 331 and 332 have a developing device unit housing such that the first blower fan 331 is on the upstream side in the air flow direction and the second blower fan 332 is on the downstream side in the air flow direction. 61 are arranged in series.

  And these 1st and 2nd ventilation fans 331 and 332 are arrange | positioned so that the axis line of a fan axis | shaft may mutually differ. That is, the first blower fan 331 is provided so that the fan shaft is located at the boundary between the first ventilation hole 611 and the second ventilation hole 612, and thereby the apparatus main body via the blower duct 32 and the first ventilation hole 611. The air outside the apparatus body 111 is taken in, and the air inside the apparatus main body 111 is taken in via the gap 34 and the second ventilation hole 612. On the other hand, the second blower fan 332 is provided such that the fan shaft is substantially along the center line of the blower duct 32, so that the air flows through the blower duct 32 in an unbiased state.

  In the developing device unit housing 61, a partition plate 613 is horizontally provided below the second blower fan 332, and a space in the developing device unit housing 61 is partially partitioned vertically. A metal plate 614 for attaching a motor 118 for driving a cleaning member (not shown) of the sub-charging device 114h is vertically attached to the lower surface of the partition plate 613. The sheet metal 614 has a planar dimension reaching the bottom wall of the developing device unit casing 61 and both side walls in the width direction, thereby blocking the air path below the partition plate 613. In other words, in the developing device unit housing 61, the air flow path F is formed only on the upper side of the partition plate 613 on the downstream side of the partition plate 613.

  As shown in FIG. 4, the exhaust unit 40 includes an exhaust duct 41 erected on the bottom plate 111 g (see FIG. 4) of the apparatus main body 111 in a state where the back plate 111 f of the apparatus main body 111 is shared, and exhaust in the bottom plate 111 g. A plurality of exhaust holes 42 drilled in a portion corresponding to the lower end surface of the duct 41 are provided. The exhaust duct 41 has a left-right width dimension set substantially the same as a width dimension of the cooled parts 51, 52, 53, and a height dimension of the lowest dimension of the cooled parts 51, 52, 53. Thus, the air that has flowed through the cooled parts 51, 52, 53 is exhausted from the exhaust hole 42 to the outside through the exhaust duct 41.

  According to the cooling structure configured as described above, the first and second blower fans 331 and 332 are driven, so that external air passes through the intake port 31 and temporarily covers the front plate 117 ′ and the back surface of the front cover body 117. After being introduced into the air passage space V between the plate 117 ″ and the dust is removed through the filter 326, the dust is removed and supplied to the cooled part 51 through the air duct 32. The air after the cooling process passes through the exhaust duct 41 and is discharged from the exhaust hole 42 to the outside.

  Next, the operation of the intake portion 30 of the cooling structure will be described in more detail based on FIG. When the first and second blower fans 331 and 332 are driven, the air outside the apparatus main body 111 is introduced into the air passage space V through the intake port 31, and further passes through the blower duct 32 as it is. From 611, the developing device unit casing 61 flows through. In addition, the air around the gap 34 in the apparatus main body 111 passes through the second ventilation hole 612 and once hits the motor 118 and the sheet metal 614, and then crosses the partition plate 613 from above to the above air flow. Merge and flow through the developing device unit housing 61.

  At this time, since the first blower fan 331 and the second blower fan 332 are arranged in series on the upper side of the partition plate 613, the amount of air passing through the air flow path F is increased and the developing device 114d having a large heat generation amount is efficiently disposed. Can be cooled to. On the other hand, since only the first blower fan 331 is disposed below the partition plate 613, the amount of air sent to the motor 118 is reduced, but the amount of heat generated by the motor 118 is extremely small compared to the developing device 114d. The air that has been warmed by removing heat from the motor 118 merges with the air flow toward the air flow path F without stagnation, so that a sufficient cooling effect can be obtained even with a small amount of air.

  Further, according to this configuration, since it is not necessary to increase the rotational speed of each fan 331 or 332 in order to increase the fan air volume, noise such as fan motor drive noise and fan wind noise is suppressed, The quietness of the forming device is not impaired.

  Furthermore, when developing the electrostatic latent image on the photosensitive drum 114a, even if toner more than necessary is supplied from the developing device 114d and dust is scattered around, it flows through the developing device unit housing 61. Since dust is blown off by the air flow, it is possible to prevent the toner from dropping into the conveyance path formed thereunder, and as a result, an effect of preventing the paper conveyed through the conveyance path from being stained can be expected.

  A filter 326 is stretched on the inlet side of the air duct 32 so as to cover the air duct 32, and the first and second air blowing fans 331 and 332 in the cooled part 51 are driven via the air duct 32. Thus, the air taken into the cooled part 51 is cleaned.

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

  (1) In the above embodiment, the case where the cooled portion 51 is the developing device unit housing 61 has been described as an example. However, the cooled portion is a cleaning device unit housing, a fixing device unit housing, or the like. In addition to those that are set as the cooled parts alone, two or more may be combined and set as the cooled parts.

  (2) In the above embodiment, the air duct 32 is formed in a rectangular tube shape, but the present invention is not limited to the air duct 32 having a rectangular tube shape, depending on the situation. You may form by the cylindrical shape or the cylindrical body of another shape.

  (3) In the above embodiment, the exhaust hole 42 of the exhaust part 40 is provided in the bottom plate 111g of the apparatus main body 111. Instead, the exhaust hole 42 is provided on the back plate 111f side of the apparatus main body 111. Also good. In this way, it is not necessary to provide the exhaust duct 41, which can contribute to the reduction of the part cost.

  (4) In the above embodiment, the two blower fans 331 and 332 are provided in the cooled part 51, but in the present invention, these blower fans 331 and 332 are provided in the cooled part 51. However, the present invention is not limited to this, and may be provided in the air duct 32 provided in the front cover body 117. By doing so, it becomes possible to perform maintenance of the two blower fans 331 and 332 with the front cover body 117 opened, and it is possible to improve the maintainability.

1 is an external perspective view showing an embodiment of an image forming apparatus according to the present invention. These are explanatory drawing of front sectional view for demonstrating the internal structure of an image forming apparatus same as the above. These are the perspective views of an image forming apparatus same as the above, and have shown the state by which the front cover body was open | released. FIG. 3 is an explanatory view of a cross-sectional side view of the multi-function machine viewed along a line crossing the developing device unit casing in the longitudinal direction in order to explain the cooling structure of the image forming apparatus. FIG. 5 is a partially enlarged view of FIG. 4 focusing on the periphery of the intake portion in the cooling structure of the image forming apparatus. These are the fragmentary sectional views which focused on the periphery of the suction part in the cooling structure of an example of the conventional image forming apparatus. These are the fragmentary sectional views which focused on the periphery of the suction part in the cooling structure of the other example of the conventional image forming apparatus. These are the fragmentary sectional views which focused on the suction part periphery in the cooling structure of the further another example of the conventional image forming apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 11 Multifunction device 30 Air intake part 31 Air inlet 32 Air blow duct 34 Gap 40 Exhaust part 51, 52, 53 Cooled part 61 Developing device unit housing 111 Device main body 111f Back plate 111g Bottom plate 111h Sub charging device 112 Supply Paper section 112a Paper feed cassette 113 Paper transport section 113a Transport roller pair 113b Switchback section 114 Image forming section 114 Developing device 114c Exposure device 114a Photoconductor drum 114b Main charging device 114d Developing device 114e Transfer device 114f Cleaning device 114g Discharge device 114h Sub Charging device 115 Fixing device 116 Image reading unit 117 Front cover body 118 Motor 119 Document reading device 120 Paper discharge tray 331 First blower fan 332 Second blower fan 611 First ventilation hole 612 Second Kazeana 613 partition plate 614 of sheet metal P Paper V air passing space

Claims (2)

An air intake section for sucking air into the apparatus main body, an exhaust section for exhausting air introduced into the apparatus main body through the air intake section, and a cover disposed between the air intake section and the exhaust section in the apparatus main body. In an image forming apparatus comprising a cooling unit,
The intake section includes an intake port provided corresponding to the cooled portion, and a plurality of blower fans that blow air sucked from the intake port to the cooled portion,
An image forming apparatus, wherein the plurality of blower fans are arranged in series with respect to an air flow direction.   The plurality of blower fans are composed of two fans, a large fan and a small fan, the large fan is upstream in the air flow direction, the small fan is downstream in the air flow direction, and the large fan and the small fan fan 2. The image forming apparatus according to claim 1, wherein the axes are arranged with different axes.

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