JP2007025545A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the influence of heat on components including an exposure part and other than a fixing device by efficiently discharging heat from the fixing device to the outside even though an image forming apparatus is miniaturized. <P>SOLUTION: Since the air which is the outside air sucked from the first air intake port of a housing, is warmed after cooling a control part, a power source part or the exposure part, etc. is sent from the exhaust port of the first air duct to the second air duct, mixed with the air fetched from the second air intake port 200. The temperature of the air mixed with outside air is lowered in the second air duct and sent toward a path for passing the air between the fixing device 28 and a process cartridge 44 after the air is increased. Since the process cartridge 44 is cooled to low temperature by the air mixed with the outside air having the lowered temperature, a sensitive material and toner which are easily deteriorated by being heated in the process cartridge 44 can be prevented from deterioration by being kept at low temperature. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electrophotographic image forming apparatus that can reduce the influence of heat on other components including an exposure unit even when downsized and can efficiently discharge heat from a fixing device to the outside.

  In general, an electrophotographic image forming apparatus employs a configuration in which a toner image is transferred to a sheet and the toner image is fixed to the sheet. A thermal pressure fixing device using heat and pressure is generally used for fixing a toner image. Radiant heat or the like generated from this type of fixing device may adversely affect other components.

  In particular, in a miniaturized image forming apparatus, since the constituent elements are arranged in a concentrated manner, there is an increased possibility that the heat generated from the fixing device affects other constituent elements. For example, when the heat generated from the fixing device enters the exposure unit, the components (for example, a plastic lens and a scanner motor) constituting the exposure unit become high temperature, and the refractive index changes due to the thermal expansion of the plastic lens. The bearing life of is shortened. Therefore, the image forming apparatus is provided with a blowing unit that discharges heat of the fixing device to the outside of the apparatus.

  In the air blowing means for discharging heat to the outside provided in the conventional image forming apparatus, the power supply device and the control device as heat sources are provided between the first air intake port and the air blowing fan, and the optical writing device is the second. Between the air intake and the blower fan. Further, the fixing device is provided between the blower fan and the air outlet.

  The blower fan receives air that has cooled each of the power supply device, the control device, and the optical writing device, and cools the air by sending an air flow mainly to the space around the lower side of the fixing device. The structure which discharges via is proposed (for example, refer patent document 1).

However, in the conventional image forming apparatus, in order to reduce the size, the air used for cooling the power supply device or the like is cooled by sending an air flow mainly to the space around the lower side of the fixing device with a blower fan. As a result, there is a problem that it is difficult to prevent the temperature of the fixing device from rising due to the cooling of the fixing device uniformly and the circulation of warm air used for cooling to the equipment inside the image forming apparatus. is there.
JP 2004-341374 A

  In view of the above-described problems, the present invention can uniformly cool the fixing device, and further prevent the warmed air used for cooling inside the image forming apparatus from circulating and preventing the temperature from rising. It aims at providing newly.

  The image forming apparatus according to claim 1 of the present invention records an image carrier that carries a toner image, an exposure unit that exposes the image carrier, and a toner image formed on the image carrier inside a housing. In an image forming apparatus in which a transfer unit that transfers onto a medium, a fixing device that fixes a toner image transferred onto a recording medium to a recording medium, a control unit, and a power supply unit are arranged, a first air intake of a housing is arranged. A first air flow path composed of a blower fan and a duct that cools the outside air sucked from the inlet to at least one of the control section, the power supply section, and the exposure section; and a duct of the first air flow path A second air flow path having a duct connected to the discharge port and supplying air toward the fixing device; and a second air intake opening provided to take outside air into the second air flow path; An exhaust port for exhausting the air that has cooled the fixing device out of the housing; Characterized in that it has.

  With the configuration described above, the air that has been cooled by the outside air sucked from the first air intake port of the housing and cooled by the control unit, the power supply unit, the exposure unit, or the like is discharged from the first air flow path. Is supplied to the second air flow path, mixed with the air taken in from the second air intake port in the second air flow path, the temperature is lowered, and the fixing device is increased after the temperature is increased. The fixing device can be cooled more effectively.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the duct of the second air flow path is between the fixing device and the process cartridge containing at least the image carrier and the developing device. The air is sent toward a passage through which air flows.

  By configuring as described above, in addition to the operation and effect of the invention according to claim 1, the control unit, the power supply unit, the exposure unit, or the like is cooled by the outside air sucked from the first air intake port of the housing. The warmed air is sent from the outlet of the first air passage to the second air passage, and the air taken from the second air inlet in the second air passage is After being mixed and the temperature lowered, the air is sent to a passage through which air flows between the fixing device and the process cartridge, so that the process cartridge is cooled by the air that has been mixed with the outside air and lowered in temperature. Therefore, for example, the control unit, the power supply unit, the exposure unit, etc. can be cooled to a lower temperature as compared with the case where the control unit, the power supply unit or the exposure unit is cooled only by warmed air. Photosensitive material that is easily deteriorated Maintaining the toner in a low temperature, it is possible to prevent deterioration.

  According to a third aspect of the present invention, the air blown out from the duct of the second air flow path of the image forming apparatus according to the first or second aspect of the present invention is one side in the height direction with respect to the fixing device. After being divided and flowed to the other side, the air is exhausted to the outside from an upper exhaust port provided in the upper part of the housing as an exhaust port and an air exhaust port provided in the rear surface of the housing as an exhaust port. It is configured to be configured as described above.

  By configuring as described above, in addition to the operation and effect of the invention according to claim 1 or 2, the fixing device is divided into one side and the other side with respect to the height direction. Since cooling can be performed simultaneously from both sides, the fixing device can be cooled on average and quickly.

  According to a fourth aspect of the present invention, in the image forming apparatus according to the third aspect, an exhaust fan is provided for exhausting air from an air discharge port provided on the back surface of the housing.

  By configuring as described above, in addition to the operation and effect of the invention according to claim 3, since the air heated from the inside of the housing is forcibly exhausted by the exhaust fan, it is possible to prevent hot air from being trapped inside the housing. .

  According to a fifth aspect of the present invention, there is provided the image forming apparatus according to any one of the first to fourth aspects, wherein the recording medium that forms a part of the housing includes the duct of the second air flow path. It is characterized by using a surface side member of the discharge part to be discharged and a duct member integrally formed therewith.

  By configuring as described above, in addition to the operation and effect of the invention according to any one of claims 1 to 4, the configuration can be simplified by sharing the members.

  According to a sixth aspect of the present invention, in the image forming apparatus according to any one of the first to fifth aspects, the second air intake port is a discharge port of the duct of the first air flow path. The gap between the second air flow path and the duct connected to the second air flow path is formed as a gap for taking in outside air.

  According to a seventh aspect of the present invention, in the image forming apparatus according to any one of the first to sixth aspects, the end of the discharge port of the duct of the first air flow path is connected to the second air flow. It arrange | positions below the upper end part of the duct of a road, It is characterized by the above-mentioned.

  According to an eighth aspect of the present invention, in the image forming apparatus according to the seventh aspect of the present invention, the connection portion constituting a part of the discharge port of the duct of the first air flow path and the duct of the second air flow path are provided. The surface side member of the discharge part which constitutes a part is overlapped so as to open a gap, and at least one of the connection portion or the surface side member is provided with means for maintaining the gap interval.

  According to a ninth aspect of the present invention, in the image forming apparatus according to the fifth or eighth aspect, the second air intake port constitutes a part of the discharge port of the duct of the first air flow path. It is bent from the top cover so as to be bent in a substantially L-shaped cross section, and is narrow toward the inner side of the end side of the surface side member forming the discharge portion constituting a part of the duct of the second air flow path. It is characterized in that it is configured between an intake auxiliary portion that is formed so as to sink at an interval and an end side portion of the surface side member.

  By configuring as in the invention of claim 8 or claim 9, in addition to the operation and effect of the invention of claim 5 or claim 8, the second air intake port has an overlap structure or an intake air. The structure of the auxiliary portion prevents the inside of the image forming apparatus main body from being directly seen, so that the laser beam leaking inside the image forming apparatus main body is prevented from leaking outside through the second air intake port ( Laser safety), and the appearance and design can be kept good.

  According to a tenth aspect of the present invention, in the image forming apparatus according to the fifth, eighth, or ninth aspect, at least a second air intake port that takes outside air into the second air flow path is provided. It is characterized in that it is configured on the front side in the discharge direction of the recording medium in the surface side member that becomes the discharge portion.

  According to an eleventh aspect of the present invention, in the image forming apparatus according to the fifth, eighth, ninth, or tenth aspect, the second air take-in takes outside air into the second air flow path. At least a part of the mouth is arranged at a position deviated from the recording medium ejected on the surface side member to both sides in the ejection direction.

  By configuring as described above, in addition to the function and effect of the invention according to claim 5, claim 8, claim 9, or claim 10, the second air intake port is provided on both lateral sides of the discharge portion. When the recording medium is provided in each of the sections, the sheet of the recording medium on which the image has been formed is discharged, and a part of the second air intake port on the front side in the discharge direction of the recording medium in the surface side member of the discharge section is blocked. Even in this case, since the outside air is taken into the third duct from the second air intake ports on both lateral sides of the discharge part, it is possible to prevent the cooling performance from being lowered.

  According to the image forming apparatus of the present invention, the fixing device can be cooled uniformly, and further, the outside air is mixed with the warm air used for cooling in the apparatus inside the image forming apparatus, and the temperature is lowered before the air is supplied. There is an effect that the temperature of the internal device can be prevented from unnecessarily rising.

  An image forming apparatus according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic longitudinal sectional view showing an image forming apparatus. In the image forming apparatus 10, a discharge portion 14 is disposed on an upper surface portion of a housing of the image forming apparatus main body 12, and a lower portion inside the image forming apparatus main body 12 is illustrated. A sheet feeding cassette 16 is disposed, and a sheet conveyance path 24 that is a recording medium continuing from the sheet feeding cassette 16 to the discharge unit 14 is configured.

  Inside the image forming apparatus main body 12, along the conveyance path 24, an image carrier 34, a charging device 48, a developing device 50, and a cleaning device 52 are housed and integrated in the cartridge main body. Further, the fixing device 28 is arranged on the downstream side in the conveying direction. Further, an optical writing device 54 is disposed at a position facing the image carrier 34. The process cartridge 44 may be a cartridge body in which at least the image carrier 34 and the developing device 50 are housed and integrated.

  Inside the image forming apparatus main body 12, the power supply device 102 and the control device 104 are arranged in parallel at a predetermined position above the optical writing device 54. The power supply apparatus 102 receives external power and supplies power to each unit constituting the image forming apparatus 10. The control device 104 controls each part constituting the image forming apparatus 10.

  The image forming apparatus main body 12 is configured to extend in a substantially vertical direction from the paper feed cassette 16 at the lower end to the fixing device 28 in the vicinity of the back surface (right side in FIG. 1) of the image forming apparatus main body 12 in the conveyance path 24. Provide a part.

  In the image forming apparatus main body 12, a sheet of a recording medium is pulled out from the paper feed cassette 16 by a take-out roll 18 such as a pick-up roll installed near the back end of the paper feed cassette 16, and the transfer device 32 of the process cartridge 44. It is carried out so as to be sandwiched between the image carrier 34.

  The image carrier 34 is made of, for example, a photoconductor, and a scanning image is irradiated from the optical writing device 54 to form a latent image. The transfer device 32 is configured as a transfer roll, and is disposed so as to face the image carrier 34 so as to be in rolling contact therewith. The charging device 48 is constituted by a charging roll, and is in rolling contact with the image carrier 34 to uniformly charge the image carrier 34.

  The process cartridge 44 is formed with an opening 62 for allowing the scanning light emitted from the optical writing device 54 to the image carrier 34 to pass therethrough. The optical writing device 54 is disposed in the vicinity of the front of the image forming apparatus main body 12 (in the vicinity of the left end in FIG. 1) in the image forming apparatus main body 12 and in parallel with the paper feed cassette 16.

  Although not shown, the optical writing device 54 houses therein a polygon unit including a polygon mirror and a motor that rotates the polygon mirror, and an optical component such as a semiconductor laser and other plastic lenses. Scanning light is emitted from an exit window formed on the process cartridge side, and this scanning light is applied to the image carrier 34 through the opening 62 of the process cartridge 44, and image information is scanned and exposed to form a latent image on the image carrier 34. Is formed. The latent image formed on the image carrier 34 in this way is visualized with toner by the developing device 50.

  In the developing device 50, toner is supplied from the toner storage chamber to the developing chamber 60. A developing roller 72 is disposed in the developing chamber 60, and a toner image is carried on the latent image on the image carrier 34 by the developing roller 72 to be visualized.

  A sheet of a recording medium is carried between the image carrier 34 on which the toner image is formed and the transfer device 32 at a predetermined timing, and passes between the transfer device 32 and the image carrier 34. The toner image is transferred to the surface.

  The image carrier 34 is cleaned by the cleaning device 52 after the transfer of the toner image is completed. The cleaning device 52 includes a cleaning blade and a toner collection chamber, and the toner scraped off from the surface of the image carrier 34 by the cleaning blade is collected in the toner collection chamber.

  The sheet of the recording medium to which the toner image has been transferred is guided out by the sheet conveyance guide 30 from the image carrier 34 side toward the fixing device 28 on the longitudinal portion of the conveyance path 24. The sheet conveyance guide 30 is configured so that a large number of ventilation holes are formed in the plane of the guide plate so that air can pass smoothly.

  The fixing device 28 includes a heating roll 40 and a pressure roll 42, and forms a nip portion that rolls in a state where the heating roll 40 and the pressure roll 42 are pressurized, and a toner image is formed in the nip portion. When the transferred sheet passes, the toner image is fixed to the sheet.

  The sheet of the recording medium on which the toner image is fixed in this manner is discharged from the discharge port of the conveyance path 24 onto the discharge unit 14 and stocked. The discharge portion 14 has a low discharge port portion and is inclined so as to gradually increase toward the front direction (left direction in FIG. 1). The discharge unit 14 is attached to the image forming apparatus main body 12 so that the lower end of the discharge unit 14 is pivotally attached by a hinge 15 and is rotatable. The image forming apparatus main body 12 is configured such that the process cartridge 44 can be attached and detached by rotating and releasing the discharge portion 14 upward.

  Further, a shutter 84 that opens and closes the side surface of the image carrier 34 on the transfer device 32 side is rotatably and movably mounted on the process cartridge 44 arranged in the image forming apparatus main body 12.

  The shutter 84 is guided by a guide (not shown) provided in the image forming apparatus main body 12 so as to be opened and closed in conjunction with the attachment / detachment of the process cartridge 44.

  That is, before the process cartridge 44 is mounted, the shutter 84 closes the side surface portion of the image carrier 34 with an elastic body (not shown) to protect the image carrier 34, and the process cartridge 44 is attached to the image forming apparatus main body 12. After the mounting, as shown in FIG. 1, the image carrier 34 moves to a retracted position where the side surface portion of the image carrier 34 is opened against an elastic body (not shown).

  In this retracted position, the shielding portion of the shutter 84 faces the heating roll 40 of the fixing device 28 to block radiant heat from the heating roll 40 and prevent the process cartridge 44 from being heated.

  The shutter 84 is formed with a number of ventilation holes (not shown). Further, the shutter 84 is configured to form a gap between the shutter 84 and the process cartridge 44 when in the retracted position.

  The vent hole provided in the shutter 84 communicates with a gap formed between the shutter 84 and the process cartridge 44 at the retracted position, and this gap constitutes a part of an air passage for cooling air and is guided through the vent hole. The process cartridge 44 is configured to be cooled by flowing air into the gap by the air.

  Further, the air that has passed through the gap formed between the shutter 84 and the process cartridge 44 at the retracted position cools the air around the fixing device 28 and passes through the sheet conveyance guide 30.

  In the image forming apparatus main body 12 configured as described above, the sheet of the recording medium fed from the sheet feeding cassette 16 by the unloading roll 18 such as a pick-up roll is guided to the transport path 24 and the transfer device 32 is taken at a predetermined timing. The toner image is transferred to and from the image carrier 34, the toner image transferred to the recording medium sheet is fixed by the fixing device 28, and the recording medium sheet on which the image is formed is discharged from the discharge port 26 through the discharge unit 14. The operation to discharge is performed.

  Next, a cooling air blowing system provided in the image forming apparatus 10 configured as described above will be described.

  Although not shown in the figure, the image forming apparatus 10 is provided with an upper air intake port, which is a first air intake port, above the one side surface of the housing. The lower air intake port that is the first air intake port is provided, and the second air intake port 200 is provided around the discharge portion 14 that hits the upper surface of the housing. In order to discharge the air sucked from the air intake port 2 and the second air intake port 200, an air exhaust port 124 is provided on the back surface of the housing, and an upper exhaust port 206 is provided at a predetermined position on the upper surface of the housing.

  The upper air intake port is disposed so as to substantially face each of the power supply device 102 and the control device 104. Further, the upper air intake port takes in external air (outside air) into the image forming apparatus 10 when the blower fan 97 shown in FIGS. 1 and 3 rotates.

  The lower air intake port is disposed below the optical writing device 54. The lower air intake port takes in outside air below the optical writing device 54 by the rotation of the blower fan 97.

  As shown in FIGS. 1 and 2, the second air intake port 200 provided on the upper surface side of the housing is formed in the top cover 202 which is a fixed member constituting the upper surface portion of the housing, and the top cover 202. A structure is provided in which a gap for allowing air to flow in is provided between the discharge portion 14 formed in a substantially rectangular shape that is attached to the substantially rectangular opening portion so as to be openable and closable.

  In addition, the air discharge port 124 provided in the image forming apparatus main body 12 is disposed at substantially the center of the back surface of the image forming apparatus 10. Further, an exhaust fan 126 is disposed inside the air exhaust port 124 provided in the image forming apparatus main body 12 so as to face the air exhaust port 124, and air in the image forming apparatus main body 12 is exhausted from the air exhaust port 124. Make it possible.

  Next, an air flow path for guiding the air sucked from the upper and lower air intake ports and the second air intake port 200 described above to the air discharge port 124 will be described.

  This air flow path is an optical writing device at the front side central portion inside the image forming apparatus main body 12 for the outside air sucked by the blower fan 97 from the upper and lower air intake ports arranged on one side surface of the image forming apparatus main body 12. 54, a first duct 98 for guiding the main blower fan 96 disposed above 54, and a second air intake formed on the free end side of the discharge unit 14 for the air sent out by the main blower fan 96. The first air flow path constituted by the second duct 114 for blowing the air to the mouth 200 side together and the discharge port of the second duct 114 are connected to the fixing device 28 and the process cartridge 44. A second air flow path constituted by a third duct 204 for sending air toward a passage through which air flows.

  The first duct 98 is disposed from the entrance facing the blower fan 97 to substantially the center of the optical writing device 54, and is formed in a casing shape that covers the upper side of the optical writing device 54 and the upstream side of the main blower fan 96. Air is received from an inlet portion provided on the blower fan 97 side so that air can be supplied to the main blower fan 96 side.

  The inlet of the first duct 98 is connected to the above-described upper air intake through the power supply device 102 and the control device 104, respectively. That is, when the blower fan 97 rotates, the power supply device 102 and the control device 104 are cooled by the outside air taken in from the upper air intake port.

  At the same time, the inlet of the first duct 98 is connected to the lower air intake through the optical writing device 54. The lower air intake port is disposed on one side of the image forming apparatus 10 and below the optical writing device 54, and is connected to the lower side of the first duct 98 so that air hits the optical writing device 54. .

  Further, a main blower fan receiving portion is formed on the back side of the first duct 98 (right side in FIG. 1), and the main blower fan 96 is inserted and disposed in the main blower fan receiving portion.

  Note that the main blower fan 96 is arranged away from the outline of the image forming apparatus main body 12 to reduce the noise generated by the main blower fan 96 from coming out of the image forming apparatus main body 12.

  The second duct 114 constituting the air flow path is arranged on the downstream side in the air supply direction of the main blower fan 96, and the air forcedly supplied from the main blower fan 96 is the width of the front side surface of the image forming apparatus main body 12. It is configured as a fixed duct member having a structure that guides it so as to flow in the direction and flow toward the back side of the discharge portion 14.

  For this reason, the second duct 114 is provided with a blower fan mounting portion on the substantially central front side, and the main blower fan 96 is mounted on the blower fan mounting portion. In addition, the second duct 114 is provided with first air guide surfaces 136a and 136b (shown in FIG. 3) extending from both sides of the blower fan mounting portion. Further, the second duct 114 is provided with a second air guide surface 138 (shown in FIG. 3) facing the first air guide surfaces 136a and 136b.

  Further, the second duct 114 is adjacent to the second air guide surface 138 so as to connect a part constituting the air discharge port to the discharge unit 14 via the second air intake port 200. The top cover 202 is an upper surface of the housing of the image forming apparatus main body 12 to be configured.

  The second duct 114 is connected to the first duct 98 at the blower fan receiving portion of the first duct 98, and is attached to the upper part of the optical writing device 54 together with the first duct 98.

  In the second duct 114 configured as described above, the air flow from the main blower fan 96 is guided by the first air guide surfaces 136a and 136b and the second air guide surface 138, and spreads to both sides. The second air guide surface 138 and a part of the top cover 202 pass through an air discharge port, and are sent to the third duct 204 side.

  The third duct 204 disposed following the air discharge port of the second duct 114 is configured integrally with the discharge unit 14.

  As described above, the discharge unit 14 is pivoted upward about the hinge 15 to open the large opening formed in the top cover 202 from the large opening to the inside of the image forming apparatus main body 12. The process cartridge 44 installed in the apparatus is configured to be removable.

  At the same time, the discharge portion 14 is provided with a bent flat plate-like duct member 14B at a predetermined interval from the surface side member 14A to the inside of the apparatus, and the surface side member 14A and the duct member 14B are not shown. It connects with a wall member, for example, is comprised in the duct structure integrated in the cylinder shape of a rectangular opening.

  Thus, since the discharge part 14 is shared with the 3rd duct 204, compared with the case where the 3rd duct 204 is comprised with another member, the number of members is reduced and space saving of the 3rd duct 204 is saved. Thus, the shape of the third duct 204 is simplified, the structure is simplified, the image forming apparatus 10 is downsized, and the outside air is actively supplied from the third duct 204 without being restricted by design and safety. It is possible to provide an inexpensive product that can be inhaled.

  The second air intake port 200 disposed in the portion of the third duct 204 is in accordance with Bernoulli's law, and the second air intake port 200 is supplied from the second duct 114 by the fast air flow passing through the third duct 204. The second air intake port 200 is configured to be sucked into the third duct 204.

  For this reason, the portion corresponding to the second air intake port 200 around the large opening of the top cover 202 is bent into a substantially L-shaped cross section and is directed toward the inner side of the end portion of the discharge portion 14. The intake auxiliary portion 202A is integrally formed to extend so as to enter a narrow space.

  Further, in the second air intake port 200, the space between the portion from the top cover 202 to the intake auxiliary portion 202A and the end portion of the front surface side member 14A of the discharge portion 14 facing the air intake auxiliary portion 202A. In order to keep the distance between the top cover 202 and the air intake auxiliary part 202A side or the front surface side member 14A side one or both, a function of a spacer spanned between the grooves of the second air intake port 200 is provided. A plurality of the rib members 14 </ b> C are arranged at predetermined intervals.

  The air intake assisting portion 202A is formed in the entire portion of the second air intake port 200 extending from the free end side portion of the discharge portion 14 and the lateral sides of the discharge portion 14 following the free end portion. As described above, when the second air intake ports 200 are provided on both lateral sides of the discharge unit 14, a sheet of a large-sized recording medium on which an image has been formed is placed on the discharge unit 14. Even when the second air intake port 200 in the free end portion 14 of the exhaust pipe 14 is blocked, the outside air is introduced into the third duct 204 from the second air intake ports 200 in the lateral portions of the discharge portion 14. Therefore, it is possible to prevent the cooling performance from being deteriorated. Note that the discharge unit 14 is formed in such a size that the second air intake ports 200 on both lateral sides thereof are not blocked even when a maximum-size recording medium sheet is placed.

  The duct shape of the second duct 114 and the third duct 204 is configured such that the flow velocity of air becomes the fastest at a portion corresponding to the second air intake port 200, and the second air intake port 200. It is desirable to configure so that the amount of air flowing into the third duct 204 through the air increases.

  Further, the second air intake port 200 configured in this way has a structure in which the inside of the image forming apparatus main body 12 is not directly visible because the air intake auxiliary section 202A is provided in the groove portion. The laser beam leaking inside 12 can be prevented from leaking to the outside through the second air intake port 200 (laser safety), and the appearance and design can be kept good.

  In addition to the above-described configuration, the second air intake port 200 includes a top cover 202 disposed as a part of a housing constituting the duct of the second air flow path, and a second air flow path. By using the surface side member of the discharge part which constitutes a part of the housing which is a duct, various structures can be provided in which an air intake port formed as a gap for taking in outside air is provided.

  For example, the connection portion of the top cover 202 that constitutes a part of the discharge port of the duct of the first air flow path is disposed below the surface side member 14A that constitutes a part of the duct of the second air flow path. Thus, the second air intake port 200 is configured.

  In addition, the connecting portion of the top cover 202 that constitutes a part of the discharge port of the duct of the first air flow path and the surface side member 14A that constitutes a part of the duct of the second air flow path have a gap between them. It may be configured such that it is overlapped so as to be opened, and means such as a rib for maintaining a gap interval is provided at least on one of the connecting portion of the top cover 202 or the surface side member 14A.

  The exhaust port of the third duct 204 is configured such that air is blown to the front of the fixing device 28 to divert (up and down) to one side and the other side with respect to the height direction of the fixing device 28. The fixing device 28 is configured to be efficiently cooled. For example, the exhaust port of the third duct 204 is directed to the heating roll 40 of the fixing device 28, and the central portion of the third duct 204 in the height direction is the central portion of the fixing device 28 in the height direction. You may comprise so that it may correspond.

  The top cover 202 of the image forming apparatus main body 12 is supplied with air, which is supplied from the third duct 204 and is blown to the fixing device 28 and blows upward, almost directly above the fixing device 28. An upper exhaust port 206 for exhausting outside is provided.

  Further, the air sent from the third duct 204 and applied to the fixing device 28 and blown downward in the fixing device 28 passes through an air flow path between the fixing device 28 and the process cartridge 44. The sheet conveying guide 30 is configured to pass through a large number of vent holes and be discharged from the air discharge port 124 to the outside of the housing of the image forming apparatus main body 12 by an exhaust fan 126 disposed at the front thereof.

  Next, the cooling action by the cooling air blowing system provided in the image forming apparatus 10 configured as described above will be described.

  In this cooling blower system, the blower fan 97, the main blower fan 96, and the exhaust fan 126 are rotationally driven to suck outside air from the upper air intake port and the lower air intake port formed in the image forming apparatus 10. .

  The outside air sucked from the upper air intake port cools each of the power supply device 102 and the control device 104, enters the first duct 98, and is guided to the blower fan 96. At the same time, the outside air sucked from the lower air intake port cools the optical writing device 54, enters the first duct 98, and is guided to the main blower fan 96.

  The cooling air guided to the main blower fan 96 is sent out toward the second duct 114 in a state where heat is taken from the power supply device 102, the control device 104, and the optical writing device 54 and the temperature is higher than the outside air. It is. In the second duct 114, the flow of cooling air is spread on both sides by the first air guide surfaces 136 a and 136 b and the second air guide surface 138, and the second air guide surface 138 and the top cover are expanded. The air passes through an air discharge port constituted by a part of 202 and is sent to the third duct 204 side at a high flow rate.

  Thus, when cooling air is sent through the third duct 204 at a high flow rate, as understood from Bernoulli's law, the second air intake port 200 enters the third duct 204. A large amount of outside air is taken in and mixed with the high-temperature air flowing through the third duct 204 to remove heat from the control device 104 and the optical writing device 54 and sufficiently higher than the air having a temperature higher than the outside air. Cooling air having a low temperature is blown from the exhaust port of the third duct 204 toward the fixing device 28 and the process cartridge 44.

  At this time, since the cooling air blown out from the exhaust port of the third duct 204 is mixed with a large amount of outside air sucked from the second air intake port 200, the temperature is sufficiently low. Since the amount is large, the fixing device 28 and the process cartridge 44 can be sufficiently cooled.

  Further, in the fixing device 28, a large amount of cooling air at a sufficiently low temperature is directly blown by the main blower fan 96 and flows so as to be separated vertically in the height direction of the fixing device 28. As a result, the fixing device 28 can be efficiently cooled.

  Further, in the process cartridge 44, a large amount of outside air sucked from the second air intake port 200 is mixed and cooled by a sufficiently low temperature and a large amount of cooling air, so that it is cooled to a sufficiently low temperature. .

  Since this process cartridge 44 does not have a large heat source inside, if the process cartridge 44 is cooled with low-temperature cooling air mixed with outside air in this way, heat is taken from the control device 104 and the optical writing device 54. Therefore, the process cartridge 44 can be maintained at a lower temperature as compared with the case where the process cartridge 44 is cooled by the cooling air having a high temperature.

  Therefore, it is possible to sufficiently prevent the photosensitive material, toner, etc. in the process cartridge 44 from being adversely affected by the temperature rise.

  Further, in the cooling blower system provided in the image forming apparatus 10, the air heated by cooling the fixing device 28 and the process cartridge 44 is quickly discharged from the air discharge port 124 by the exhaust fan 126 to the housing of the image forming apparatus main body 12. While being forcedly discharged to the outside and exhausted from the upper exhaust port 206, it is possible to prevent hot air from being trapped inside the image forming apparatus main body 12.

  Further, in the cooling air blowing system provided in the image forming apparatus 10, the heat generated by the fixing device 28 does not affect the control device 104, the power supply device 102, and the optical writing device 54 that are easily affected by heat. can do. In addition, since the power supply device 102 and the control device 104 are disposed above the optical writing device 54, it is possible to reduce the heat generated by the power supply device 102 and the control device 104 from rising and entering the optical writing device 54. be able to.

  It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that various other configurations can be taken without departing from the gist of the present invention.

1 is a cross-sectional view illustrating an image forming apparatus according to an embodiment of the present invention. 1 is a plan view showing an image forming apparatus according to an embodiment of the present invention. 1 is a schematic perspective view showing main devices arranged inside an image forming apparatus according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 12 Image forming apparatus main body 14 Discharge part 14A Surface side member 14B Duct member 14C Rib member 24 Conveyance path 28 Fixing device 32 Transfer device 34 Image carrier 40 Heating roll 42 Pressure roll 44 Process cartridge 50 Developing device 54 Optical writing device 60 Developing chamber 84 Shutter 96 Main blower fan 97 Blower fan 98 First duct 102 Power supply device 104 Control device 114 Second duct 124 Air exhaust port 126 Exhaust fans 136a, 136b Air guide surface 138 Air guide surface 200 First Two air intake ports 202 Top cover 202A Intake auxiliary portion 204 Third duct 206 Upper exhaust port

Claims (11)

An image carrier that carries a toner image inside the housing, an exposure unit that exposes the image carrier, a transfer unit that transfers the toner image formed on the image carrier onto a recording medium, and the recording medium In an image forming apparatus in which a fixing device that fixes a toner image transferred thereon to a recording medium, a control unit, and a power supply unit are arranged.
A first air flow path configured by a blower fan and a duct that cools external air sucked from the first air intake port of the housing by hitting at least one of the control unit, the power supply unit, and the exposure unit. When,
A second air flow path having a duct connected to a discharge port of the duct of the first air flow path and supplying air toward the fixing device;
A second air intake opening provided to take outside air into the second air flow path;
An exhaust port for exhausting air that has cooled the fixing device out of the housing;
An image forming apparatus comprising:   The duct of the second air flow path feeds air toward a passage through which air flows between the fixing device and a process cartridge containing at least the image carrier and the developing device. The image forming apparatus according to claim 1.   The air blown out from the duct of the second air flow path is diverted to one side and the other side in the height direction with respect to the fixing device, and then flows through the exhaust port. 2. The exhaust system according to claim 1, wherein exhaust air is exhausted from an upper exhaust port provided in an upper portion of the housing and an air exhaust port provided in a rear surface of the housing as the exhaust port. Item 3. The image forming apparatus according to Item 2.   The image forming apparatus according to claim 3, further comprising an exhaust fan for exhausting air to the outside from an air discharge port provided on a back surface of the housing.   The duct of the second air flow path uses a surface side member of a discharge part that forms a part of the housing and discharges the recording medium, and a duct member that is integrated with the surface side member. The image forming apparatus according to claim 1, wherein the image forming apparatus is configured as described above.   The second air intake port is a gap for taking in outside air between the discharge port of the duct of the first air flow channel and the duct of the second air flow channel connected to the second air flow channel. The image forming apparatus according to claim 1, wherein the image forming apparatus is formed.   The end of the discharge port of the duct of the first air flow path is disposed below the upper end of the duct of the second air flow path. The image forming apparatus according to claim 1.   The connection part constituting a part of the discharge port of the duct of the first air flow path, and the surface side member of the discharge part constituting a part of the duct of the second air flow path. The image forming apparatus according to claim 7, further comprising: a unit that is overlapped so as to open a gap, and that maintains at least one of the connection portion and the surface-side member.   The second air intake port is bent and extended in a substantially L-shaped cross section from a top cover that constitutes a part of the discharge port of the duct of the first air flow path, and the second air intake port An air intake auxiliary portion formed so as to enter a predetermined narrow interval toward the inner side of the end side portion of the surface side member forming the discharge portion constituting a part of the duct of the air flow path; and the surface The image forming apparatus according to claim 5, wherein the image forming apparatus is configured between the side edges of the side members.   The second air intake port for taking outside air into the second air flow path is configured at least on the front end side in the discharge direction of the recording medium in the surface side member serving as the discharge portion. The image forming apparatus according to claim 5, claim 8, or claim 9.   At least a part of the second air intake port for taking outside air into the second air flow path is arranged at a position deviating from the recording medium discharged onto the surface side member to both sides in the discharge direction. The image forming apparatus according to claim 5, claim 8, claim 9, or claim 10.

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