JP2009098218A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To evenly send a current of cooling air to a plurality of substrates disposed in contact with the inside of the shield chassis. <P>SOLUTION: The image forming apparatus has, in a predetermined frame, a box-shaped shield chassis 50 made of metal, wherein a plurality of option substrates 60 on which control circuits for image forming process are formed are attached to this shield chassis 50 so as to be freely detached. The shield chassis 50 includes: a pair of side plates 54 parallel to the direction in which the option substrates 60 are attached or detached; an upper batten 52 extended between one edges of the pair of side plates 54 and having vent holes 521; and a lower batten 51 extended between the edges of the pair of side plates 54 opposite to the upper batten 52 and having vent holes 511; and an insulation film 56 serving as a partition member, which partitions the shield chassis 50 extended between the upper batten and lower batten 52 and 51 into a plurality of substrate storage chambers 57 in order to divide a current of air blown toward the upper batten plate 52 from a fan device 70 and further blown into the shield chassis 50 via the vent holes 521. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus having a cooling structure for performing a cooling process on a heat generation source including a control circuit board for image forming processes.

  The image forming apparatus performs the image forming process based on the image information read by a predetermined reader attached thereto or the image information transmitted from an external device such as a computer, and then the sheet fed from the sheet feeding unit. Then, a toner image transfer process is performed, and a fixing process of the toner image onto the paper is subsequently performed in the fixing unit. The paper after the fixing process is discharged to a paper discharge tray provided outside the apparatus, a cylinder discharge tray provided in the apparatus, or the like.

  In such an image forming apparatus, heat sources are provided at various places, and predetermined cooling structures are provided in order to prevent heat accumulation from these heat sources. Among the heat generation sources, the one having the largest amount of heat generation may be a fixing unit including a halogen lamp or the like as a heat source that performs fixing processing by heating the paper. Next, although the heat generation amount is not as great as that of the fixing unit, a CPU substrate including a CPU or the like in which an electronic circuit is incorporated, an HDD substrate including an HDD or the like as a storage device, and the like can be cited as a heat source.

  By the way, since the heat generation amount is extremely large among these heat generation sources, a dedicated powerful fan device and a dedicated ventilation path for passing outside air sucked by the fan device are provided. In addition, since the fixing portion is appropriately cooled by the airflow flowing through the ventilation path, it is effectively prevented that the fixing portion becomes an abnormally high temperature.

  On the other hand, as a cooling structure of an image forming apparatus targeting various substrates in which an electronic circuit is incorporated, for example, those described in Patent Documents 1 and 2 are known.

  First, in the cooling structure described in Patent Document 1, a first wiring board on which a first circuit having a CPU is mounted and a second wiring board on which a second circuit is mounted are arranged in parallel to each other. The second wiring board is provided with a vent hole, and a wide flat cable is bridged from the opposite edge portions of the vent hole toward the first board, and an air flow is sent toward the vent hole. A cooling fan is provided.

  According to the cooling structure having such a configuration, the airflow from the cooling fan collides with the first wiring board through the ventilation holes formed by the pair of flat cables through the ventilation holes, and changes the direction by 90 ° in a collective state. Then, in order to circulate on the first wiring board, a heat source such as the CPU is effectively cooled by arranging, for example, a CPU to be cooled at a position along the flow path.

  Further, the one in Patent Document 2 is provided with a first box for storing a substrate such as a CPU formed by pressing a sheet metal, and a second box for storing a substrate such as the storage device. The first and second boxes are integrated with each other through a partition wall, and a large number of ventilation holes are formed over the entire surface.

According to the cooling structure having such a configuration, an air flow is generated by driving a predetermined fan provided at an appropriate position in the main body of the image forming apparatus, and the air flow extends over the entire surfaces of the first and second boxes. The air is supplied into each box from any one of the many vent holes provided, and after being subjected to a cooling process on a heat source such as an internal CPU or storage device, it is discharged to the outside from any other vent hole.
JP 2005-340598 A JP 2007-095967 A

  By the way, in the cooling structure of Patent Document 1, when a plurality of objects to be cooled are arranged on the first and second wiring boards, an air flow for cooling is evenly supplied thereto. As a result, there is a problem that the cooling efficiency of each object to be cooled varies, and the cooling process cannot be appropriately performed as a whole.

  The same applies to the cooling structure of Patent Document 2, and airflow introduced into each box through a ventilation hole that is naturally determined by the installation state of the fans is generated by a plurality of substrates disposed in the box. However, it is not always supplied uniformly, and as a result, there is a problem that variation occurs in the cooling process.

  The present invention has been made in view of such a conventional situation, and has a cooling structure capable of uniformly feeding a cooling airflow to a plurality of substrates as heat sources inscribed in a shield chassis. An object of the present invention is to provide an image forming apparatus.

  The invention according to claim 1 is an apparatus main body having a housing accommodating part, an air passage formed in the apparatus main body and passing through the housing accommodating part, and a fan device for generating an air flow in the air venting path, A shield chassis that is fixed to the housing housing and on which a plurality of circuit boards are detachably mounted. The shield chassis includes a pair of side plates parallel to a direction in which the substrates are attached and detached, and one of the pair of side plates. A top plate having a vent hole spanned between the edges, a bottom plate having a vent hole spanned between the edge portions of the pair of side plates facing the top plate, and the fan device from the top plate to the bottom plate The shield chassis, which is installed between the top plate and the bottom plate, is divided into a plurality of substrate storage chambers in order to divert the airflow that is blown toward and blown into the shield chassis through the vent holes. Partition part It is characterized in that it comprises and.

  According to this configuration, the airflow from the fan device blown toward the top plate or bottom plate of the shield chassis is introduced into the shield chassis through the vent holes formed in the top plate or bottom plate, and the shield After the substrate mounted in the chassis is cooled by heat exchange, it is discharged to the outside through the opposite vent hole.

  And since the partition member that divides the shield chassis into a plurality of substrate storage chambers is installed between the top plate and the bottom plate, the predetermined fan device can transfer the top plate or the bottom plate with the substrate stored in each substrate storage chamber. The airflow is blown into the shield chassis through the vent holes drilled in the top plate or the bottom plate, and is first equally divided into each substrate storage chamber by the diversion action of the partition member. After that, the air flow in the other side of the substrate storage chamber is rectified without interfering with the airflow in the other substrate storage chamber due to the rectifying action of the partition member, and the substrate in the substrate storage chamber is cooled. It is discharged from the hole to the outside.

  According to a second aspect of the present invention, in the first aspect of the invention, the partition member is formed of an insulating film.

  According to this configuration, since the partition member provided between the substrate storage chambers adjacent to each other is formed of the insulating film, the substrates stored in the substrate storage chambers are short-circuited with each other by the insulating film. Therefore, it is possible to prevent the occurrence of inconvenience that the function of the substrate is impaired by a short circuit.

  According to a third aspect of the present invention, in the second aspect of the present invention, the insulating film has a top plate side, a bottom plate side, and an insertion / removal port side through which the substrate is inserted into and removed from the substrate storage chamber. It is fixed to the shield chassis, and the opposite side to the insertion / removal port is a free end.

  According to such a configuration, since the insulating film has a free end on the side opposite to the insertion / removal port, the portion for fixing the insulating film to the shield chassis is reduced in that portion, and the independence of each substrate storage chamber is increased. Contribute to reduction of assembly man-hours while securing. Moreover, since the length dimension of an insulating film can be shortened, it contributes to the reduction in material cost by that much.

  According to the image forming apparatus of the present invention, since the inside of the shield chassis that stores the substrate is divided into the plurality of substrate storage chambers by the partition member, the airflow blown into the shield chassis through the inlet-side vent hole Are divided into the respective substrate storage chambers by the partition members, and not only the flow is smoothed by the rectifying action of the partition members, but also the air currents in the other substrate storage chambers do not interfere with each other. The substrate can be uniformly cooled by heat exchange. As a result, a proper cooling process is always applied to the plurality of substrates housed in the shield chassis, and the cooling effect can be improved comprehensively for each substrate.

  In addition, even when the board is mounted only in a part of the storage space in the shield chassis, the airflow is reliably diverted by the partition member, so the airflow flows exclusively through the non-substrate mounting part of the storage space. Inconveniences such as insufficient cooling of the substrate can be avoided.

  FIG. 1 is a front perspective view showing an embodiment of an image forming apparatus to which a cooling structure according to the present invention is applied. FIG. 2 is an explanatory front sectional view showing an embodiment of the internal structure of the image forming apparatus shown in FIG. FIG. 3 is a partially cutaway perspective view of the image forming apparatus shown in FIG. 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 rearward. That's it. Incidentally, in FIG. 3, the left and right indicated by X are opposite to the actual left and right sides of the page.

  First, the overall configuration of the image forming apparatus 10 will be described with reference to FIG. 3 as necessary based on FIGS. The image forming apparatus 10 exemplified in this embodiment is a so-called in-body discharge type copying machine, and includes an image forming unit 12 (FIG. 2), a fixing unit 13 (FIG. 2), and an apparatus main body 11. A paper storage unit 14, a paper discharge unit 15, an image reading unit 16, and an operation unit 17 are formed. The paper discharge unit 15 is formed by recessing a part of the apparatus main body 11 below the image reading unit 16, and the image forming apparatus 10 is referred to as an in-body paper discharge type.

  The apparatus main body 11 includes a lower main body 111 having a rectangular parallelepiped shape in appearance, an upper main body 112 having a flat rectangular parallelepiped shape disposed above the lower main body 111, and the upper main body 112 and the lower main body 111. And a connecting portion 113 interposed therebetween. The connecting portion 113 is a structure for connecting the paper discharge portion 15 between the lower main body 111 and the upper main body 112 to each other, and is erected from the left portion of the lower main body 111. Yes. The upper body 112 is supported on the upper end of the connecting part 113 at the left side.

  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, as shown in FIG. 1, the operation portion 17 protrudes forward from the front edge portion of the upper body 112.

  The paper storage unit 14 includes a paper cassette 141 that can be inserted into and removed from the apparatus main body 11. The sheet cassette 141 stores a sheet bundle P1 (FIG. 2). When the image forming process is performed, the sheets P are fed out from the sheet bundle P1 one by one, sent to the image forming unit 12, and the sheet P is subjected to the image forming process (printing process). In the present embodiment, the paper cassette 141 is provided in two stages.

  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 an in-cylinder paper 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 is transferred is transferred from the lower part of the connection unit 113 to the cylinder P. The paper is discharged toward the inner paper discharge tray 151.

  The image reading unit 16 includes a contact glass 161 mounted on the upper surface opening of the upper main body 112 for placing a document, and an openable / closable document pressing cover 162 for pressing the document placed on the contact glass 161. And a scanning mechanism 163 (FIG. 2) that scans an image of the document placed on the contact glass 161.

  Then, the analog information of the document image read by the scanning mechanism 163 is converted to a digital signal and then output to an exposure unit 123 described later, and is subjected to image forming processing.

  The operation unit 17 is used to input processing information relating to image forming processing. The operation unit 17 is used to input the number of sheets P to be processed, a numeric keypad 171 (FIG. 1), various other operation keys, and touch input. An LCD (Liquid crystal display) 172 (FIG. 1) or the like is provided.

  Further, a manual feed tray 18 is provided on the right surface of the lower main body 111 at a position directly above the sheet storage unit 14. The lower side of the manual feed tray 18 is pivotally supported around the support shaft 181, and is positioned between a closed posture that stands up to close the manual feed port and an open posture that protrudes rightward. It can be changed. The manual feed tray 18 is used to manually feed the paper P one by one in a state where the posture is set to the open posture.

  A transport unit 184 (FIG. 2) and a relay unit 185 are provided between the manual feed tray 18 and a later-described photosensitive drum 121 (FIG. 2) of the image forming unit 12. The sheet P (FIG. 2) fed in is sent out toward the nip portion between the photosensitive drum 121 and a transfer roller 125, which will be described later, via the transport unit 184 and the relay unit 185.

  Further, a maintenance door 19 for maintenance that can be opened and closed is provided on the left surface of the lower main body 111, and an in-body discharge tray 152 that can be opened and closed is provided immediately above the maintenance door 19. Yes. The paper P for which printing processing has been completed in the image forming unit 12 is selectively discharged to either the out-body discharge tray 152 or the in-body discharge tray 151.

  Hereinafter, the internal structure of the image forming apparatus 10 will be described in more detail with reference to FIG. As shown in FIG. 2, the image forming unit 12 is provided with a photosensitive drum 121 at a substantially central portion thereof. The photosensitive drum 121 is uniformly charged on its peripheral surface by a charging unit 122 provided immediately to the right while rotating clockwise around the drum center.

  Then, an electrostatic latent image is formed on the peripheral surface of the photosensitive drum 121 by the laser beam from the exposure unit 123 based on the image information of the original image read by the image reading unit 16. A developer (hereinafter referred to as toner) is supplied from a developing unit 124 provided below the photosensitive drum 121 toward the electrostatic latent image, whereby a toner image is formed on the peripheral surface of the photosensitive drum 121. .

  The sheet P sent out from any one of the sheet cassettes 141 in the sheet storage unit 14 is sent to the photosensitive drum 121 on which the toner image is formed via the sheet vertical conveyance path 101 and the registration roller pair 142. Then, the toner image on the peripheral surface of the photosensitive drum 121 is transferred onto the sheet P by the action of the transfer roller 125 arranged to face the photosensitive drum 121 on the left side of the photosensitive drum 121. The sheet P on which the toner image is transferred is separated from the photosensitive drum 121 and sent to the fixing unit 13.

  After the transfer of the toner image to the paper P is completed, the photosensitive drum 121 is continuously rotated in the clockwise direction, so that its peripheral surface is cleaned by the cleaning device 126 provided immediately above it. The charging unit 122 is headed for the image forming process.

  The fixing unit 13 includes a fixing roller 131 provided with an energization heating element such as a halogen lamp inside, and a pressure roller 132 disposed opposite to the fixing roller 131 on the left side. The sheet P sent from the image forming unit 12 is subjected to a toner image fixing process by obtaining heat while passing through the nip portion between the fixing roller 131 and the pressure roller 132.

  The paper P after the fixing process is selectively placed inside the cylinder of the paper discharge unit 15 via the paper discharge conveyance path 102 provided above the fixing unit 13 when the paper P is for single-sided printing. The paper is discharged to the paper discharge tray 151 or discharged to the out-body discharge tray 152.

  On the other hand, when the sheet P after the fixing process is for double-sided printing in which the single-sided printing process is completed, the first half is discharged into the cylinder via the reciprocating conveyance path 103 provided above the discharge conveyance path 102. After being discharged into a temporary evacuation space 153 formed above the paper tray 151, the paper is reversely fed through the reverse feed path 104, supplied to the image forming unit 12 again with the front and back sides reversed, and printed on the back side. Processing is performed. The paper P on which double-sided printing has been completed is discharged to the paper discharge tray 151 or the out-body discharge tray 152.

  In such an image forming apparatus 10, the lower main body 111 is provided with a cover member 191 that can be opened and closed with respect to the image forming unit 12 immediately inside the maintenance door 19. This cover member 191 is disposed in a state of being wrapped on the right side of the closed maintenance door 19. The cover member 191 is pivotally supported around a support shaft 192 supported by the lower body 111 with the lower end portion positioned slightly above the lower end portion of the maintenance door 19. Such a cover member 191 rotates forward and backward about the support shaft 192 to close the left surface of the image forming unit 12 (indicated by a solid line in FIG. 2), and to open the left surface. The posture can be changed between the postures (indicated by a two-dot chain line in FIG. 2).

  In the state where the cover member 191 is set to the closed posture, the sheet vertical conveyance path 101 for conveying the sheet P fed from the sheet cassette 141 or the manual feed tray 18 to the right side of the cover member 191 is provided. Is formed.

  Such a cover member 191 is provided when the paper P is jammed by changing the posture of the cover member 191 to the open posture when a paper jam occurs in the vertical paper conveyance path 101 corresponding to the left side of the image forming unit 12. Is exposed to the outside so that the jammed paper P can be removed.

  In the image forming apparatus 10 configured as described above, there are three locations in the apparatus main body 11 as heat sources to be cooled. One place is a fixing unit 13 having a fixing roller 131 provided with an energization heating element such as a halogen lamp. Another place is the option board 60 accommodated in the shield chassis 50 of the control circuit etc. accommodating portion 20. The last one is a power supply circuit board provided in the power supply circuit unit 29 disposed below the shield chassis 50.

  On the other hand, a back plate (not shown) that is erected in the vertical direction is provided at a position in the rear portion of the apparatus main body 11 and slightly inside from the rear surface. The fixing unit 13, which is a very large heat source, is provided on the front side of the back plate. On the other hand, the storage unit 20 such as the control circuit and the power supply circuit unit 29 that are not so large but require cooling processing are provided on the back plate. It is arranged on the rear side of the face plate. As a result, the control circuit storage unit 20 and the power supply circuit unit 29 are isolated from the fixing unit 13 in the rear of the apparatus main body 11 by the back plate, and the heat of the fixing unit 13 is controlled by the control circuit storage unit 20 and the power supply circuit unit 29. Has been made so as not to affect.

  In the present embodiment, the control circuit storage unit 20 is targeted as a portion to which the cooling structure according to the present invention is applied. On the other hand, since the heat generation amount of the fixing unit 13 is much larger than these, the fixing unit air cooling fan 133 (FIG. 3), which is a dedicated powerful cooling device, is employed. Accordingly, the cooling system of the fixing unit 13 is different from the cooling process of the control circuit storage unit 20 and the power circuit unit 29.

  Further, on the back side of the apparatus main body 11, a detachable back side cover body 28 for closing the back opening of the apparatus main body 11 as shown in FIG. 3 is provided. The rear cover body 28 is mounted in the apparatus main body 11 and is driven into the apparatus main body 11 by driving a fan apparatus 70 (to be described later) for cooling the fixing unit air cooling fan 133 and the control circuit storage unit 20. It serves as a part of the ventilation path that distributes the airflow of the sucked outside air. In particular, the air flow sucked by the fan device 70 flows through the air passage 22 set so as to flow through the board mounting space 21 in the control circuit housing 20, and cools the control circuit board 40 and the option board 60. Apply.

  At the upper position on the left side (−X side) of the back side cover body 28, a fixing unit cooling air inlet 281 is provided so as to face the fixing unit air cooling fan 133, and the right side (+ X side). In the upper position, an intake port (circuit unit intake port 282) for sucking outside air for cooling the control circuit storage unit 20 and the power supply circuit unit 29 is provided. Further, at the lower position on the right side (+ X side) of the back side cover body 28, an exhaust port (circuit unit exhaust port 283) that discharges the air flow used for cooling the control circuit storage unit 20 and the power circuit unit 29. Is provided.

  The cooling structure according to the present embodiment is provided in the control circuit storage 20. FIG. 4 is a perspective view showing an embodiment of the control circuit storage 20. 5 and 6 are diagrams showing an embodiment of the shield chassis 50 that houses the option board 60. FIG. 5 is a perspective view of the shield chassis 50, and FIG. 6 shows the option board 60 in the shield chassis 50 of FIG. It is a partially notched top view in the state in which was stored. 4 to 6 are the same as those in FIG. 1 (X is the left-right direction (-X: leftward, + X: rightward), Y is the front-rear direction (-Y: forward, + Y: backward)).

  First, as illustrated in FIG. 4, the control circuit storage unit 20 includes a housing (housing housing unit) 30 having a box shape whose bottom surface is open. The housing 30 houses a control circuit board 40 including a CPU (central processing unit) and the like, and an option board 60 such as facsimile software or a printed board (the option board 60 is also a kind of control circuit board). And a fan device 70 that cools the control circuit board 40 and the option board 60 in the shield chassis 50 by blowing an air current.

  The housing 30 includes a pair of side plates 31 in the left-right direction, a substrate 32 installed between the front edges of the pair of side plates 31, and a top plate 33 installed between the upper edges of the pair of side plates 31. is doing. A substrate mounting space 21 is formed in a space surrounded by the side plates 31, the substrate 32, and the top plate 33. The opening on the rear surface side of the board mounting space 21 is closed by mounting the rear cover body 28 (FIG. 3) on the apparatus main body 11, thereby forming an air passage through which airflow flows in the housing 30. .

  The control circuit board 40 is attached to an upper position on the back side of the board 32. The shield chassis 50 is fixed to the position of the lower half of the inner surface side of the side plate 31 on the right side (+ X side) and is in a state of substantially traversing the board mounting space 21 in the left-right direction. The fan device 70 is attached to an upper position on the inner surface side of the left side (−X side) side plate 31. The fan device 70 is set so that the axial flow is inclined forward and downward.

  Accordingly, by driving the fan device 70 in a state where the back side cover body 28 is mounted on the apparatus main body 11, the outside air sucked into the board mounting space 21 through the circuit portion intake port 282 (FIG. 3). The airflow is blown down obliquely toward the board mounting space 21 and then downwards, and the optional board 60 in the shield chassis 50 is cooled. After that, it flows down from the lower opening of the housing 30 toward the power supply circuit unit 29 and is used for cooling the power supply circuit unit 29.

  As shown in FIG. 5, the shield chassis 50 includes a lower eye plate (bottom plate) 51 in which a large number of ventilation holes 511 are formed, and a number of ventilation holes 521. An upper eye plate (top plate) 52 disposed opposite to each other, a back plate 53 installed between the left edge portions of the eye plates 51 and 52, and between the front edge portions and the rear edges of the eye plates 51 and 52. A pair of front and rear side plates 54 (indicated by a two-dot chain line in FIG. 5) erected between the parts, an inlet side frame plate 55 erected between the right edges of the eye plates 51 and 52, and each eye plate 51 , 52 and an insulating film (partition member) 56 extending in the left-right direction, which is provided between the opposing surfaces of the substantially central portion in the front-rear direction.

  A substrate storage chamber 57 for storing the optional substrate 60 is formed in the space before and after the insulating film 56 in the shield chassis 50. That is, in the present embodiment, two option boards 60 can be mounted in the shield chassis 50 via the insulating film 56.

  The entrance-side frame plate 55 is provided with a pair of insertion / removal ports 551 that are long in the vertical direction and are formed in the front-rear direction with the right edge of the insulating film 56 as a boundary. The option board 60 is mounted in the shield chassis 50 through these insertion / removal openings 551.

  The insulating film 56 is dimensioned so that the left and right lengths are slightly shorter than the left and right lengths of the eye plates 51 and 52. The right edge of the insulating film 56 is adhered to the entrance-side frame plate 55, while the upper and lower edges are in contact with the eye plates 51 and 52. The insulating film 56 has a free edge at the left edge when mounted on the shield chassis 50. By making the left edge part of the insulating film 56 a free end, the assembling property of the insulating film 56 with respect to the shield chassis 50 is improved as compared with the case where the front edge part is adhered.

  In addition, a substrate storage chamber 57 for storing the option substrate 60 is formed before and after the insulating film 56 in the shield chassis 50.

  The optional substrate 60 includes a rectangular substrate body 61 having a predetermined electronic circuit formed on one side thereof, and a substrate holding plate 62 attached to the right edge of the substrate body 61. A knob protrusion 63 is provided at the center of the front surface side of the substrate holding plate 62, and the option board 60 can be easily taken in and out of the substrate storage chamber 57 in the shield chassis 50 by holding the knob protrusion 63. be able to.

  The substrate cooling structure according to the present invention can sufficiently perform its function by including the insulating film 56 provided so as to bisect the inside of the shield chassis 50.

  The operation of the cooling structure according to the present invention will be described below with reference to FIG. FIG. 7 is a cross-sectional view of the shield chassis 50 shown in FIG. 6 taken along the line VII-VII. As shown in FIG. 7, the cooling airflow generated by driving the fan device 70 (FIG. 4) is blown into the shield chassis 50 through the vent holes 521 of the upper eye plate 52 of the shield chassis 50. The blown airflow is divided into two by the insulating film 56 installed between the eye plates 51 and 52 of the shield chassis 50 and introduced into the front and rear substrate storage chambers 57. At this time, since the insulating film 56 serves as a current plate, the airflow introduced into the shield chassis 50 is prevented from becoming turbulent in the shield chassis 50. As a result, the airflow in the substrate storage chamber 57 becomes a laminar flow and flows down from the front and back surfaces of the substrate body 61 while exchanging heat, and as a result, the cooling effect on the option substrate 60 is improved.

  Here, when only one option board 60 is mounted in the shield chassis 50, and the inside of the shield chassis 50 is not partitioned by the insulating film 56, the air current is wide so that the option board 60 does not exist. The option substrate 60 cannot be sufficiently cooled by flowing exclusively through the space. However, in the present embodiment, since the inside of the shield chassis 50 is partitioned by the insulating film 56 and a plurality of substrate storage chambers 57 are formed, only one option board 60 is mounted in the shield chassis 50. Even in such a case, since the insulating film 56 is provided, the airflow introduced into the shield chassis 50 is guided by the insulating film 56 and the area where the option substrate 60 is mounted. Therefore, it is possible to prevent inconvenience that the cooling process of the option board 60 becomes insufficient.

  As described above in detail, the image forming apparatus 10 according to the present embodiment includes a plurality of substrates (an optional substrate 60 in the present embodiment) on which a control circuit for image forming processing is formed in a predetermined frame of the apparatus body 11. ) Is detachably attached to a metal shield chassis 50 having a box shape.

  The shield chassis 50 extends in the direction in which the option board 60 is attached and detaches, and is installed between a pair of side plates 54 parallel to the surface of the option board 60 in a state where the option board 60 is mounted, and between the lower edges of the pair of side boards 54. The lower eye plate 51 having the vent hole 511 and the upper eye plate 52 having the air hole 521 provided between the upper edges of the pair of side plates 54 are provided. A partition is formed between the upper eye plate 52 and the lower eye plate 51 in order to divert the airflow blown from the fan device 70 toward the upper eye plate 52 and blown into the shield chassis 50 through the vent holes 521. An insulating film 56 as a member is installed, and the inside of the shield chassis 50 is partitioned into a plurality (two in this embodiment) of substrate storage chambers 57 by the insulating film 56.

  According to this configuration, the airflow from the fan device 70 blown toward the upper eye plate 52 of the shield chassis 50 is introduced into the shield chassis 50 through the vent holes 521 formed in the upper eye plate 52. The optional substrates 60 housed in the substrate housing chambers 57 in the shield chassis 50 are cooled by heat exchange and then discharged to the outside through the vent holes 521 of the lower eye plate 51.

  Since the insulating film 56 that partitions the shield chassis 50 into a plurality of substrate storage chambers 57 is installed between the upper eye plate 52 and the lower eye plate 51, the option substrate 60 is stored in each substrate storage chamber 57. By blowing an air flow from a predetermined fan device 70 toward the upper eye plate 52 or the lower eye plate 51 in a state, the air flow is shielded through a vent hole formed in the upper eye plate 52 or the lower eye plate 51. The air is blown into the chassis 50, and is first equally divided into each substrate storage chamber 57 by the diversion action of the insulating film 56, and then interferes with the airflow in the other substrate storage chamber 57 by the rectifying action of the insulating film 56. Without any mutual contact, the substrate body 61 in the substrate storage chamber 57 is cooled in a laminar flow, and discharged from the vent hole 511 of the lower eye plate 51 to the outside.

  That is, according to the image forming apparatus 10 according to the present embodiment, the inside of the shield chassis 50 that stores the substrate body 61 of the option substrate 60 is divided into the plurality of substrate storage chambers 57 by the insulating film 56, so that the entrance side The airflow blown into the shield chassis 50 through the ventilation holes 521, which are the ventilation holes, is divided into the respective substrate storage chambers 57 by the insulating film 56, and the flow is laminarized by the rectifying action of the insulating film 56. As a result, the airflow in the other substrate storage chambers 57 does not interfere with each other, and the optional substrate 60 can be uniformly cooled by heat exchange. As a result, a proper cooling process is always performed on the plurality of option boards 60 housed in the shield chassis 50, and the overall cooling effect can be improved.

  Further, even when the substrate is mounted only in a part of the storage space in the shield chassis 50, the air current is reliably diverted by the insulating film 56 as the partition member. Thus, it is possible to surely avoid the disadvantage that the airflow exclusively flows to cause the cooling treatment of the option substrate 60 to be insufficient.

  In the present embodiment, since the insulating film 56 is employed as a partition member that divides the shield chassis 50 into a plurality of substrate storage chambers 57, each option substrate 60 stored in each substrate storage chamber 57 is provided. The insulating films do not short-circuit each other, and it is possible to prevent the occurrence of inconvenience that the function of the option substrate 60 is impaired by the short-circuit.

  In the present embodiment, since the end edge of the insulating film 56 mounted in the shield chassis 50 is a free end, a portion for fixing the insulating film 56 to the shield chassis 50 correspondingly. As a result, the number of assembling steps can be reduced while ensuring the independence of each substrate storage chamber 57. Moreover, since the length dimension of the insulating film 56 can be shortened, it can contribute to the reduction of material cost by that much.

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

  (1) In the above embodiment, a copying machine is adopted as the image forming apparatus 10, but a printer or a facsimile machine may be used instead of the copying machine.

  (2) In the above-described embodiment, the airflow provided for the cooling process in the control circuit storage unit 20 and the power supply circuit unit 29 may be supplied to the fixing unit 13 via the fixing unit air cooling fan 133. By doing so, the ability of the air cooling fan 133 for the fixing unit can be reduced, which can contribute to a reduction in operation cost.

  (3) In the above embodiment, the insulating film 56 is employed as a partition member applied to the housing 30 of the control circuit storage 20, but an insulating board is employed instead of the insulating film 56. May be.

  (4) In the above embodiment, the shield chassis 50 is partitioned by the sheet of insulating film 56 and two substrate storage chambers 57 are provided. However, in the present invention, the shield chassis 50 has two chambers. The shield chassis 50 may be divided into three or more rooms by adopting two or more insulating films 56 without being limited to being partitioned.

  (5) In the above embodiment, the back plate 53 is provided in the innermost part of the shield chassis 50. However, the back plate 53 is not essential and may not be provided.

1 is a front perspective view showing an embodiment of an image forming apparatus to which a cooling structure according to the present invention is applied. It is explanatory drawing of front sectional view which shows one Embodiment of the internal structure of the image forming apparatus shown in FIG. FIG. 2 is a partially cutaway perspective view of the image forming apparatus shown in FIG. It is a perspective view which shows one Embodiment of accommodating parts, such as a control circuit. It is a perspective view which shows one Embodiment of the shield chassis which accommodates an option board | substrate. FIG. 6 is a partially cutaway plan view of the shield chassis of FIG. FIG. 7 is a cross-sectional view taken along line VII-VII of the shield chassis shown in FIG. 6 for explaining the operation of the cooling structure of the image forming apparatus according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 101 Paper vertical conveyance path 102 Paper discharge conveyance path 103 Reciprocation conveyance path 104 Reverse feed conveyance path 11 Apparatus main body 12 Image formation part 111 Lower main body 112 Upper main body 113 Connection part 121 Photosensitive drum 122 Charging unit 123 Exposure unit 124 Developing unit 125 Transfer roller 126 Cleaning device 13 Fixing unit 131 Fixing roller 132 Pressure roller 133 Air cooling fan for fixing unit 14 Paper storage unit 141 Paper cassette 142 Register roller pair 15 Paper discharge unit 151 In-body paper discharge tray 152 Out-of-body paper discharge Tray 153 Temporary evacuation space 16 Image reading unit 161 Contact glass 162 Document pressing cover 163 Scanning mechanism 17 Operation unit 171 Numeric keypad 172 LCD
18 Tray 181 Support shaft 184 Conveyance unit 185 Relay unit 19 Maintenance door 191 Cover member 192 Support shaft 20 Control circuit storage unit 21 Substrate mounting space 22 Air passage 28 Back side cover body 281 Fixing portion cooling air inlet 282 Circuit portion air intake 283 Exhaust port for circuit part 29 Power supply circuit part 30 Housing (housing housing part)
31 Side plate 32 Substrate 33 Top plate 40 Control circuit board 50 Shield chassis 51 Lower eye plate 52 Upper eye plate 511, 521 Vent hole 53 Back plate 54 Side plate 55 Entrance side frame plate 551 Insertion / extraction port 56 Insulating film (partition member)
57 Board storage room 60 Option board (control circuit board)
61 Substrate body 62 Substrate holding plate 63 Knob protrusion 70 Fan device P Paper P1 Paper bundle

Claims (3)

An apparatus main body having a housing accommodating portion;
An air passage formed in the apparatus main body and passing through the housing housing;
A fan device for generating an air flow in the air passage;
A shield chassis that is fixed to the housing accommodating portion and on which a plurality of circuit boards are detachably mounted;
The shield chassis is
A pair of side plates parallel to the attaching / detaching direction of the substrate;
A top plate having a vent hole spanned between one edge of the pair of side plates;
A bottom plate having a vent hole spanned between edges of the pair of side plates facing the top plate;
The air blower is blown from the fan device toward the top plate or the bottom plate, and is installed between the top plate and the bottom plate in order to divert the airflow blown into the shield chassis through the ventilation holes. A partition member that partitions the inside of the shield chassis into a plurality of substrate storage chambers;
An image forming apparatus comprising:   The image forming apparatus according to claim 1, wherein the partition member is formed of an insulating film.   In the insulating film, the top plate side, the bottom plate side, and the insertion / removal port side for inserting / removing the substrate with respect to the substrate storage chamber are fixed to the shield chassis, respectively, and the side opposite to the insertion / removal port is a free end. The image forming apparatus according to claim 3, wherein:

Images