JP2017161623A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that simultaneously cools a powder conveyance path and a powder conveyance unit of an image forming part, suppresses an increase in temperature of powder in a wide range to prevent blocking, and suppresses an increase in cost and increase in size of the apparatus.SOLUTION: An image forming apparatus 1 of the present invention comprises: a powder conveyance path 61 that conveys a powder; a powder conveyance unit 90 that is connected to the powder conveyance path; and a cooling device 80 that cools the powder conveyance path 61 and powder conveyance unit 90. The cooling device 80 includes an airflow source 81 and a duct 82 that is extended in parallel with the powder conveyance path 61. The duct 82 includes a first exhaust port 87 that guides the airflow to the powder conveyance path 61 and a second exhaust port 88 that guides the airflow to the powder conveyance unit 90.SELECTED DRAWING: Figure 10

Description

  The present invention relates to an image forming apparatus.

  2. Description of the Related Art Conventionally, various image forming apparatuses such as printers and copiers that form a visible image on a recording medium using a plurality of image forming elements based on input image data have been developed. In this type of image forming apparatus, for example, an apparatus using an electrophotographic system includes an image forming unit, a transfer device, and a fixing unit.

  In the image forming unit (photosensitive drum, transfer device, etc.) of such an image forming apparatus, the waste toner collected by the cleaning device passes through the waste toner conveyance path provided in each unit and is provided in the image forming apparatus main body. To the main body side waste toner conveying unit. The waste toner is transported to a developing device for reuse and used for image formation, or is transported from the main body side waste toner transport unit to a disposal case and discarded.

  Recently, each unit is densely arranged with the downsizing of the image forming apparatus, so the heat generated from the fixing unit, the drive unit, the substrate, the recording medium that holds the fixing heat through the double-sided path, etc. The temperature inside the machine is likely to rise. In particular, when the temperature of the waste toner conveying path rises, the internal waste toner may be melted and fixed, and blocking may occur. When blocking occurs, the conveyance screw and gear are damaged and waste toner is clogged, and the image forming apparatus fails.

  In order to prevent blocking of waste toner, a method of cooling or shielding the waste toner conveyance path by a cooling device is known. In the image forming apparatus, since waste toner is collected from a plurality of units such as a photosensitive drum, a primary transfer device, and a secondary transfer device, a waste toner conveyance path may be provided for each unit. The waste toner conveyance path is connected to a main body side waste toner conveyance unit provided in the main body of the image forming apparatus. Therefore, in order to prevent blocking of waste toner, it is necessary to efficiently cool the entire waste toner conveyance path.

As a method for cooling or insulating the waste toner conveyance path by a cooling device, there are a method in which an air flow is generated by a fan and a duct and air cooling is performed (Patent Document 1), and a method using a heat exchanger (Patent Document 2). .
However, the air cooling method has a narrow cooling range and can only cool the waste toner conveyance path of one unit. On the other hand, when a fan or duct is arranged in each unit, the number of parts increases and the cost increases. When cooling the waste toner conveyance paths of each unit and main body together, a large duct or fan is required.

  On the other hand, when using a heat exchanger, the cost of the heat exchanger becomes a problem. When the waste toner conveyance path is long, a large heat exchanger is required, which increases the cost.

  Accordingly, the present invention simultaneously cools the powder conveyance path and the powder conveyance unit of the image forming unit, suppresses the temperature rise of the powder in a wide range, prevents blocking, and suppresses increase in cost and size of the apparatus. It is an object to provide an image forming apparatus.

  In order to solve this problem, a powder conveyance path for conveying powder, a powder conveyance unit connected to the powder conveyance path, a cooling device for cooling the powder conveyance path and the powder conveyance unit, The cooling device includes an air flow source and a duct that runs in parallel with the powder conveyance path, and the duct includes a first exhaust port that guides the air flow to the powder conveyance path, and the powder. An image forming apparatus having a second exhaust port for guiding an air flow to a body conveyance unit is proposed.

  The powder conveyance path and the powder conveyance unit of the image forming unit can be simultaneously cooled over a wide range with a simple and small configuration, and powder blocking can be prevented. In addition, the duct can be provided so as to run parallel to the long axis direction with respect to the powder conveyance path, thereby preventing an increase in size of the apparatus. Moreover, the powder conveyance path can be cooled in a wide range by guiding the airflow along the powder conveyance path.

1 is a schematic front sectional view showing an image forming apparatus according to an embodiment. 2 is a schematic perspective view of the image forming apparatus. FIG. It is a schematic side sectional view of the cooling device concerning a 1st embodiment. It is a schematic perspective view of the cooling device. 1 is a perspective view of a specific configuration example of an image forming apparatus. It is a schematic side surface sectional view of the cooling device concerning a 2nd embodiment. It is a schematic sectional side view of the cooling device which concerns on 3rd Embodiment. It is a perspective view which shows the specific structural example of a cooling device. It is a disassembled perspective view of the same structural example. It is a schematic side sectional view of a cooling device and a secondary transfer device. It is a schematic plan view of a cooling device and a main body side waste toner conveyance unit. It is sectional drawing of the secondary transfer apparatus which concerns on embodiment. It is a schematic front sectional view of a cooling device for cooling the conveying screw of the photoconductor cleaning device. It is CC sectional view taken on the line of FIG. It is a schematic front sectional view of a cooling device for cooling the conveying screw of the developing device. It is a schematic perspective view of the conventional axial fan. It is a schematic plane sectional view of the conventional cooling device using the one-side suction type sirocco fan. It is a schematic plane sectional view of the conventional cooling device using the both sides suction type sirocco fan.

  First, an image forming apparatus 1 according to an embodiment of the present invention will be described with reference to FIGS. In this embodiment, the image forming apparatus 1 is a tandem type color copying machine.

  As shown in FIG. 1, the image forming apparatus 1 includes an automatic document feeder (hereinafter referred to as ADF) 10 and an image forming apparatus main body 11. The image forming apparatus main body 11 includes a paper feeding unit 3, an image reading unit 4, and an image forming unit 5. A front cover 6 provided on the front surface of a drawer unit 76 described later is disposed on the front side F of the image forming unit 5. In this specification, the front side F of the image forming apparatus 1 means the front side of the image forming apparatus 1, and the rear side R means the back side of the image forming apparatus 1 (see FIG. 2).

  The ADF 10 includes a document tray 20, a paper feed roller 21, a conveyance belt 22, a paper discharge roller 23, and a paper discharge tray 24. The ADF 10 is attached to the image reading unit 4 so as to be freely opened and closed via an opening and closing mechanism such as a hinge.

  The paper feed roller 21 separates the originals one by one from the bundle of originals placed on the original tray 20, and conveys the originals toward the image reading unit 4. The conveyance belt 22 conveys the original document separated by the paper feed roller 21 to the image reading unit 4. The paper discharge roller 23 discharges a document discharged from the image reading unit 4 by the conveyance belt 22 to a discharge tray 24 below the document tray 20.

  The sheet feeding unit 3 includes a sheet feeding cassette 30 and a sheet feeding unit 31. The paper feed cassette 30 accommodates recording media having different sizes. The sheet feeding unit 31 conveys the recording medium stored in the sheet feeding cassette 30 to the image forming position of the image forming unit 5.

  The image reading unit 4 includes a housing 40, a scanning optical unit 41, a contact glass 42, and driving means.

  The scanning optical unit 41 is provided inside the housing 40 and includes an LED unit. The scanning optical unit 41 emits light in the main scanning direction from the LED unit, and is scanned in the sub-scanning direction in the entire irradiation region by the driving unit. Thereby, the scanning optical unit 41 reads a two-dimensional color image of the document.

  The contact glass 42 is provided on the upper portion of the housing 40 of the image reading unit 4 and constitutes the upper surface portion of the housing 40. The driving means includes a wire fixed to the scanning optical unit 41, a plurality of driven pulleys and driving pulleys bridged by the wires, and a motor for rotating the driving pulley.

  The image forming unit 5 includes an exposure unit 51, a tandem image forming apparatus 50, an intermediate transfer belt 54, an intermediate transfer roller 55, a secondary transfer apparatus 52, a fixing unit 53 as an example of a fixing apparatus, and main conveyance. A path 70 and a reverse conveyance path 73 are included.

  As shown in FIG. 1, the exposure unit 51 is disposed adjacent to the tandem image forming apparatus 50. The exposure unit 51 performs exposure on the photosensitive drum 74 provided for each color.

  The tandem image forming apparatus 50 includes four image forming units 75 (image forming units) of yellow, cyan, magenta, and black along the rotation direction of the intermediate transfer belt 54 on the intermediate transfer belt 54. . The individual image forming means 75 includes a charging device, a developing device, a photoconductor cleaning device, a static elimination device, and the like around the photoconductive drums 74 provided for each color, which will be described in detail later. Each photosensitive drum 74 and each of the devices provided around the photosensitive drum 74 are unitized to form one process cartridge.

  The tandem image forming apparatus 50 forms a visible image (toner image) formed of toner by color-coding the photosensitive drums 74 based on the image information read by the image reading unit 4 and separated by color. It is supposed to be. The visible image formed on each photosensitive drum 74 is transferred to the intermediate transfer belt 54 between each photosensitive drum 74 and the intermediate transfer roller 55.

  On the other hand, a secondary transfer device 52 as a transfer device is provided on the opposite side of the tandem image forming device 50 with the intermediate transfer belt 54 interposed therebetween. In the illustrated example, the secondary transfer device 52 is configured such that a secondary transfer belt 56 that is an endless belt is stretched between two support rollers 57. Then, by pressing the secondary transfer belt 56 against the intermediate transfer belt 54, the toner image formed on the intermediate transfer belt 54 is transferred to the recording medium conveyed from the paper feeding unit 3 via the main conveyance path 70. It is comprised so that. As the secondary transfer device 52, a secondary transfer roller may be employed instead of the secondary transfer belt 56.

  By the way, the toner (waste toner), which is powder that has become unnecessary after remaining on the secondary transfer belt 56 after being transferred to the recording medium, is collected by a belt cleaning device 60 as a cleaning device. Thereafter, the waste toner is conveyed to a waste toner conveyance unit of the main body of the image forming apparatus by a waste toner conveyance path 61 provided below the belt cleaning device 60.

The waste toner conveyance path 61 receives heat from the fixing unit 53. In the case of duplex printing, the recording medium once heated by the fixing unit 53 and having the image fixed thereon passes through the reverse conveyance path 73 and again passes through the main conveyance path 70 to the secondary transfer device 52. Since the toner is supplied, the heat of the recording medium at this time is applied to the waste toner conveyance path 61.
Since the waste toner conveyance path 61 is heated in this way, if the internal waste toner is heated and exceeds a certain limit, the waste toner melts and cannot be conveyed, and the image forming apparatus fails. End up.

  Therefore, in the present invention, in order to solve such a problem, a cooling device 80 for cooling the waste toner conveyance path 61 is provided below the waste toner conveyance path 61. The cooling device 80 will be described in detail after FIG.

  A fixing unit 53 is provided on the downstream side in the transport direction of the recording medium of the secondary transfer device 52. The fixing unit 53 is configured by pressing a pressure roller 59 against a fixing belt 58 that is an endless belt. Then, the fixing unit 53 applies heat and pressure to the recording medium by the pressure roller 59 to melt the toner of the toner image transferred to the recording medium and fix it as a color image on the recording medium. Yes.

  As shown in FIG. 1, a reverse conveyance path 73 is provided below the secondary transfer device 52 and the fixing unit 53. The reverse conveying path 73 inverts the front and back of the recording medium discharged from the fixing unit 53 and supplies it again to the secondary transfer device 52 via the main conveying path 70 in order to form images on both sides of the recording medium. Is for.

  As shown in FIG. 2, the front cover 6 is attached to the front portion of the carrier 71. The carrier 71 is supported by the rail 72 so as to be movable in the front-rear direction (arrow FR in FIG. 2) with respect to the image forming unit 5. The carrier 71 carries the secondary transfer device 52, the fixing unit 53, the main transport path 70, and the reverse transport path 73 shown in FIG. The drawer 71 is composed of the carrier 71, the secondary transfer device 52, the fixing unit 53, the main conveyance path 70, and the reverse conveyance path 73. That is, the front cover 6 is configured integrally with the drawer unit 76, and the user grasps the operation recess 6a provided in the front cover 6 so that the front cover 6 is in the front-rear direction with respect to the image forming unit 5 (in FIG. 2). , Arrow FR), the drawer unit 76 can be pulled out or stored in the image forming unit 5.

  Further, the front cover 6 can open and close the front side F of the image forming unit 5 as the drawer unit 76 moves. When the front cover 6 is closed, that is, when the drawer unit 76 is housed inside the image forming unit 5, the front cover 6 constitutes a part of the exterior member of the image forming apparatus main body 11. .

  As described above, the secondary transfer device 52, the fixing unit 53, the main conveyance path 70, and the reverse conveyance path 73 are movable in the front-rear direction with respect to the image forming unit 5 while being held by the carrier 71. These parts are stored in the image forming unit 5 when the image forming apparatus 1 is used. On the other hand, when the above apparatuses are replaced or when the recording medium jammed in the image forming unit 5 is removed, the user can By pulling out to the front side F of the forming unit 5, the above-mentioned devices can be replaced and the recording medium can be removed. As a result, the maintenance work and the removal work of the jammed recording medium become much easier than before. Further, when the front cover is opened, the interlock switch is turned off so that the image forming apparatus 1 does not operate.

  In the present embodiment, the image forming apparatus 1 includes an image forming apparatus main body 11 including an image forming unit 5 that forms an image on a recording medium and a paper feeding unit 3 that supplies the recording medium to the image forming unit 5. In the present embodiment, the image forming apparatus 1 includes a part of the apparatus that constitutes the image forming unit 5, and a drawer unit 76 configured to be able to be taken in and out of the image forming apparatus main body 11, and a drawer unit 76. And a front cover 6 that can be opened and closed with respect to the image forming apparatus main body 11 as the drawer unit 76 moves. Further, in the present embodiment, the drawer unit 76 is provided with at least a secondary transfer device 52, a fixing unit 53, a cooling device 80, and a reverse conveyance path 73.

Next, a conventional cooling device will be described.
As shown in FIG. 16, an axial fan 83 that is normally used as a cooling means for electronic equipment performs intake and exhaust in the direction of the rotation axis of the wing. Therefore, in order to cool the exhaust by applying the exhaust to the portion to be cooled on the base member 77, it is necessary to install the axial flow fan 83 in a posture standing on the base member 77 as illustrated. Alternatively, when the axial flow fan 83 is used in the laid posture, a large duct that performs intake air and bends the airflow so that the exhausted airflow hits the object to be cooled is required. Therefore, in either case, the cooling device is increased in size. Moreover, although an axial fan is inexpensive and has a high air volume, since the static pressure is low, there is a problem that when an air flow is sent to a large duct, a pressure loss becomes large and the air flow cannot be sent sufficiently.

  On the other hand, a sirocco fan takes in air from the direction of the wing rotation axis and exhausts air in a direction perpendicular to the rotation axis direction. The sirocco fan has a single-side suction sirocco fan in which the intake port is provided only on one side, and the intake ports on both sides There is a double-sided suction sirocco fan.

FIG. 17 is a schematic plan sectional view of a conventional cooling device using a one-side suction sirocco fan.
As illustrated, the one-side suction sirocco fan 84 is placed on the base member 77 so that the upper intake port 81b is opened. Since the upper intake port 81b is provided only on one side and the intake port area is small, in order to obtain a high air volume, the outer diameter of the one-side suction sirocco fan 84 itself must be increased and the intake port must be widened. Will become larger. Further, in order to attach a duct 82 having an intake air introduction portion 82a to the intake side of the one-side suction type sirocco fan 84 and perform intake with a high air volume, it is necessary to increase the thickness of the intake air introduction portion 82a so as not to cause pressure loss. There is. Thereby, the flow of the intake air and the flow of the exhaust gas indicated by the arrows are generated, but the thickness of the duct 82 is increased, and the cooling device is enlarged in the thickness direction.

FIG. 18 is a schematic plan cross-sectional view of a conventional cooling device using a both-side suction sirocco fan.
As shown in the drawing, on both sides of the upper intake port 81b and the lower intake port 81a so that the upper intake port 81b and the lower intake port 81a of the double-side suction sirocco fan 81 (hereinafter also referred to as sirocco fan 81) are opened. A duct 82 having an intake introduction portion 82a is installed. Thereby, the flow of the intake air and the flow of the exhaust gas indicated by the arrows are generated, but the thickness of the duct 82 is increased, and the cooling device is enlarged in the thickness direction.

  Therefore, in the present invention, while using the double-side suction type sirocco fan 81, a cooling device that is compact in the height direction, has a high cooling capacity, and is low in noise has been devised. Since the intake ports exist on both sides of the both-side suction sirocco fan 81, the intake area is large, and a high air volume can be obtained with a small configuration. In addition, since the intake ports are on both sides of the double-sided suction sirocco fan 81 and the airflow of the intake air is dispersed, the amount of air sucked from the intake port on one side can be kept small, which is necessary when installing a duct on the intake side The size of the duct can be kept small.

Next, the cooling device according to the embodiment of the present invention will be described.
3 is a schematic side sectional view of the cooling device according to the first embodiment, and FIG. 4 is a schematic perspective view of the cooling device. In the image forming apparatus 1, a cooling device 80 for cooling the waste toner conveyance path 61 (powder conveyance path) which is a cooling target portion is installed below the waste toner conveyance path 61. The cooling device 80 includes a both-side suction type sirocco fan 81 and a duct 82 containing the sirocco fan 81. The duct 82 includes an opening 82d that is closed by a base member 77 on which a cooling device is installed, and a second intake port of the sirocco fan 81 at a position facing the lower intake port 81a as the first intake port of the sirocco fan 81. In the position which opposes the upper side inlet port 81b, it has the opposing surface 82b arrange | positioned by providing the clearance gap with respect to the upper side inlet port 81b. Here, at least a part of the opening 82 d of the duct 82 extends outside the end of the sirocco fan 81. Thereby, the air from the intake air inlet 82a is smoothly sucked into the lower intake port 81a through the opening 82d outside the end of the sirocco fan 81, and the intake air inlet 82a to the lower intake port 81a. Airflow path is secured. Conversely, if the opening 82d is the same size as the sirocco fan 81, when the opening 82d is closed by the base member 77, the closed space is sealed, and this air flow path cannot be secured.

  Further, the duct 82 includes an intake air introduction portion 82a connected from the intake port 86 of the duct to the opposing surface 82b, and an exhaust guide portion 82c connected to the second exhaust port 88 of the duct from the opposing surface 82b. As will be described later, the air inlet 86 is configured to suck air through an opening 93 provided in the image forming apparatus main body 11. The second exhaust port 88 is configured to blow air toward the main body side waste toner conveyance unit 90 provided in the image forming apparatus main body 11 and cool the air.

  The both-side suction type sirocco fan 81 is disposed in a posture in which it is laid down with respect to the base member 77 to which it is attached. By using the both-side suction sirocco fan 81 for the cooling device 80 and laying it on the base member 77, it becomes possible to reduce the thickness direction (downsizing / compact) and maintain a high static pressure. Here, the base member 77 is a sheet metal member that serves as a base of the drawer unit 76, and is an upper part that forms the reverse conveyance path 73 below the cooling device 80 shown in FIG. A cooling device 80 is installed on the upper part, and a waste toner conveyance path 61 that is a cooling target portion is disposed above the cooling device 80. Accordingly, when the recording medium having heat after double-sided printing passes through the reverse conveyance path 73, even if the heat from the recording medium is transmitted above the upper part of the base member 77, or from a hole that is punched in some places in the upper part. Even if it is transmitted upward, the cooling device 80 through which the external cooling air flows through the waste toner conveyance path 61 functions as a kind of air layer / heat insulation layer. Accordingly, the cooling effect on the waste toner conveyance path 61 is enhanced.

  As shown by an arrow 85 in FIG. 3, the double-sided suction sirocco fan 81 sucks air through the lower intake port 81a and the upper intake port 81b and discharges air from the exhaust port 81c. As described above, the duct 82 has the intake introduction portion 82a, the opposed surface 82b facing the upper intake port 81b with a gap, and the exhaust guide portion 82c, and is opened at a position facing the lower intake port 81a. A portion 82d is provided. Since at least a part of the outer periphery of the opening 82 d is larger than the outer end of the sirocco fan 81, the portion of the opening 82 d facing the outer shape of the sirocco fan 81 is attached by attaching the cooling device 80 to the base member 77. The air flow path is formed by being closed, and the air from the intake air introduction portion 82a is sucked not only by the upper intake port 81b but also by the lower intake port 81a through the portion of the opening portion 82d that is not closed ( FIG. 4).

  As shown in FIG. 3, the lower surface of the duct 82 has an abutting portion 82 e that abuts against the outer surface of the sirocco fan 81 on the first air inlet 81 a side at a portion where the sirocco fan 81 is disposed. The height position of the sirocco fan 81 is determined by the sirocco fan 81 abutting against the abutting portion 82e. Further, since the sirocco fan 81 is separated from the base member 77 by the height of the abutting portion 82e, an enlarged air flow path for air sucked from the lower intake port 81a is secured. The abutment portion 82e for adjusting the height position of the sirocco fan is provided to expand the air flow path as necessary in consideration of the performance (air volume / static pressure) of the sirocco fan 81 and the thickness of the duct 82. That's fine.

  The image forming apparatus main body 11 is provided with an intake opening 93 (FIG. 5) for the cooling device in its exterior portion. However, the position where the opening 93 can be disposed is limited due to design and structural limitations. Referring to FIG. 1, a recording medium that becomes high in the case of double-sided printing is conveyed above the cooling device 80, a base member 77 exists on the lower side, and a fixing unit 53 exists on the left side. For this reason, it is necessary to provide an opening 93 on the right side surface of the image forming apparatus main body 11 and provide an air flow path through which air for cooling air is sucked by the cooling device 80. However, when the sirocco fan 81 is laid down with respect to the base member 77 so as to reduce the thickness, the air suction direction of the fan itself is the vertical direction, so that air is sucked from the opening 93 on the right side surface of the image forming apparatus main body 11. A duct is required. The cooling device 80 takes in air from the side through the duct 82.

  As shown in FIG. 3, the duct 82 has an opening 82 d at a position facing the lower surface of the sirocco fan 81. When the opening 82 d is closed by the base member 77, an air flow path indicated by an arrow 85 is formed. By forming the opening 82d by notching a part of the duct 82, a space serving as an airflow path can be created, and the airflow path is widened by the thickness of the notched duct compared to the case where the opening 82d is not present. In addition, the height position of the sirocco fan 81 can be lowered, so that the thickness of the cooling device 80 can be reduced. This is particularly advantageous for an image forming apparatus in which a large number of electronic devices must be densely arranged in the internal space of the narrow drawer unit 76.

  Further, the facing surface 82b facing the upper intake port 81b with a gap is connected to the intake air introduction portion 82a and the exhaust guide portion 82c which are outside the end of the sirocco fan 81 and lower than the facing surface 82b. Thus, by forming the duct 82 in a convex shape so that only the portion facing the sirocco fan 81 protrudes, an air flow path in the vicinity of the upper intake port 81b can be secured, and the intake inlet portion 82a and the exhaust guide portion of the duct can be secured. The cooling device 80 can be downsized by reducing the thickness of 82c.

  In addition, when the downsizing by the opening 82d is sufficient and it is not necessary to reduce the thickness of the intake air introduction part 82a, the opposing surface 82b as in the cooling device 80 according to the second embodiment shown in FIG. The opposing surface 82b may be connected to the duct air inlet 82a while maintaining the height of the duct. The second embodiment is different from the first embodiment only in that the facing surface 82b and the intake air introduction portion 82a are formed flat on the upstream side of the sirocco fan 81.

  In addition, due to the performance of the sirocco fan 81 and the thickness of the duct 82, a sufficiently wide air flow path can be secured for the air sucked from the lower intake port 81a without providing the abutting portion 82e. There is also. In this case, the sirocco fan 81 may be installed on the bottom surface of the duct 82 without providing the abutting portion 82e as in the cooling device 80 according to the third embodiment shown in FIG. In the third embodiment, the abutment portion 82e is not provided, the sirocco fan 81 is further disposed below, and the cooling device 80 is formed more compactly in the thickness direction. Different from the second embodiment.

  Further, the sirocco fan 81 can generate a large noise during high-speed rotation, but the generation of noise can be suppressed by enclosing the sirocco fan 81 with the duct 82.

FIG. 5 is a perspective view of a specific configuration example of the image forming apparatus.
As described above, the exterior portion of the image forming apparatus main body 11 is provided with the opening 93 for intake of the cooling device. Although the drawer unit 76 is pulled out from the image forming apparatus main body 11, the cooling device 80 is located below the secondary transfer device 52, so that it cannot be seen in FIG. 5. A unit side opening 94 is provided on the right side surface of the front cover 6, and the unit side opening 94 is positioned on the back side of the opening 93 when the drawer unit 76 is stored. Another fan is provided inside the unit side opening 94, and outside air is sucked by the fan through the unit side opening 94 and the opening 93 and through a gap at the edge of the closed front cover 6. The The sucked air flows in the longitudinal direction (lateral direction) of the front cover 6, and then passes through the suction port 86 of the duct of the cooling device 80 arranged at right angles to the longitudinal direction and in the front-rear direction of the image forming apparatus main body 11. It is sucked by the fan 81. Air sucked by the sirocco fan 81 flows in the duct 82 and exits from the first exhaust port 87 and the second exhaust port 88 of the duct. Air exiting from the first exhaust port 87 flows toward the back of the apparatus while cooling the waste toner conveyance path 61. Air exiting from the second exhaust port 88 flows to the back side while cooling the main body side waste toner transport unit 90 disposed on the back side of the apparatus. Finally, the air that has exited from the first exhaust port 87 and the second exhaust port 88 is discharged outside the machine through a hole or gap in the rear panel provided on the opposite side of the front cover 6.

  When a sufficiently strong airflow is formed by the sirocco fan 81, the another fan may not be provided. Further, the intake inlet 82a of the duct of the cooling device 80 is connected to an extension portion that is bent at a right angle and extends in the longitudinal direction (lateral direction) of the front cover 6 and connected to the back side of the unit side opening 94. Good. In this case, the another fan may be provided inside the extension.

FIG. 8 is a perspective view showing a specific configuration example of the cooling device, and FIG. 9 is an exploded perspective view of the configuration example.
The duct 82 includes an upper duct part 82f and a lower duct part 82g. The both-side suction sirocco fan 81 is disposed on the abutting portion 82e formed on the lower duct part 82g, the lower duct part 82g is covered with the upper duct part 82f, and both parts are fixed by screwing or the like. The cooling device 80 is assembled. Further, the assembled cooling device 80 can be fixed to the base member 77 by screwing or the like. As shown in the drawing, in order to ensure a sufficient distance between the upper intake port 81b of the sirocco fan 81 and the opposed surface 82b of the duct, the opposed surface 82b is formed in a convex shape higher than the intake air introduction portion 82a and the exhaust guide portion 82c. ing. However, the height of the opposing surface 82b is minimized to ensure sufficient intake from the upper intake port 81b, and its top is formed flat. Thereby, the internal space of the narrow drawer unit 76 can be used effectively. The width of the facing surface 82b is about half of the width of the upper duct part 82f. This is whether the sirocco fan 81 requires a smooth airflow with little airflow, exhaust flow, and pressure loss. May be changed.

  A first exhaust port 87 is formed in the upper duct component 82f at a height that is located above approximately half of the height of the exhaust port 81c when the cooling device 80 is assembled. Further, the lateral width of the first exhaust port 87 extends over a part of the lateral width of the upper duct component 82 f, and this lateral width substantially matches the lateral width of the exhaust port 81 c of the sirocco fan 81. Further, as can be seen from the lower duct component 82g in FIG. 9, the first exhaust port 87 includes a straight path 82m along the airflow from the exhaust port 81c of the sirocco fan 81 and an enlarged path 82p wider than the straight path 82m. It is located corresponding to the channel enlarged portion 82n located between them. The air flow path in the straight path 82m is the narrowest and constant, the air flow path in the flow path expanding portion 82n increases from upstream to downstream, and the air flow path in the expanded path 82p is the widest and substantially constant. This is due to the following reason. That is, since the discharged airflow is likely to be disturbed near the exhaust port 81c, if the first exhaust port 87 is too close to the exhaust port 81c, the airflow from the first exhaust port 87 also becomes unstable. On the other hand, if the first exhaust port 87 is too far from the exhaust port 81c, the distance from the sirocco fan 81, which is the air flow generation source, increases, and the air flow from the first exhaust port 87 becomes weaker with respect to the cooling target portion. Insufficient cooling. In addition, if the flow passage expanding portion 82n and the expansion passage 82p are not provided, air is exhausted from the first exhaust port 87 and the second exhaust port 88 while passing air through the narrow air flow path, resulting in pressure loss and smooth air flow. It is because it is difficult to form.

  The first exhaust port 87 is located near the center in the longitudinal direction of the duct 82, and this position corresponds to the substantially central portion in the longitudinal direction of the waste toner conveyance path 61 that is a cooling target portion. Further, the angle of the first exhaust port 87 is formed such that the airflow from the first exhaust port 87 is discharged obliquely upward toward the back side of the apparatus and flows to the back side of the apparatus while cooling the waste toner conveyance path 61. ing. Thereby, the part of the back side from the center of the longitudinal direction of the duct 82 in which heat tends to be generated can be intensively cooled. As described above, the height and width of the first exhaust port 87, the position from the exhaust port 81c, the angle, and the like are such that a sufficient exhaust flow rate can be obtained from the first exhaust port 87, and the downstream side from the first exhaust port 87. The second exhaust port 88 is determined by whether or not a sufficiently strong air flow can be obtained.

  As shown in FIG. 9, the exhaust guide portion 82c has an inclined portion 82h inclined downward on the downstream side of the first exhaust port 87, and a curved portion 82i curved from the inclined portion 82h. As viewed in a plan view, the duct 82 is configured in a substantially straight line from the intake port 86 to the inclined portion 82 h, and the curved portion 82 i is curved toward the main body side waste toner conveyance unit 90. The inclined portion 82h and the curved portion 82i will be described later.

  As shown in FIG. 9, near the center of the lower duct part 82g and in the vicinity of the exhaust port 81c of the sirocco fan 81, a wall portion 82j is formed that widens the air flow path from the upstream side toward the downstream side. . The upstream portion of the wall portion 82j extends in a straight line to form the straight path, and the downstream portion expands obliquely to form the flow path expanding portion. The expansion path is formed further downstream of the flow path expansion portion. Due to the wall 82j, the air flow path is narrow in the vicinity of the exhaust port 81c and wide at a position away from the exhaust port 81c. As a result, a smooth airflow with little pressure loss is formed, and a balanced amount of airflow is discharged from the first exhaust port 87 and the second exhaust port 88. The presence / absence or the length or angle of the wall portion 82j can be selected depending on the shape / thickness of the duct 82 and the like.

  Further, as can be seen from FIGS. 8 and 9, the intake air introduction portion 82a, the opposing surface 82b and the exhaust guide portion 82c of the duct 82 are integrally formed. As a result, the number of parts is reduced, the manufacturing cost of the duct 82 is reduced, and the airtightness of the airflow path is improved.

Next, the positional relationship between the cooling device and the cooling target portion will be described with reference to FIG.
FIG. 10 is a schematic side sectional view of the cooling device 80 and the secondary transfer device 52. A waste toner conveyance connecting portion 91 is connected to the waste toner conveyance path 61 of the secondary transfer device 52. When the drawer unit 76 including the secondary transfer device 52 is accommodated in the image forming unit 5, the waste toner conveyance is performed. The path 61 is connected to the main body side waste toner transport unit 90 via the waste toner transport connecting portion 91. The waste toner collected by the belt cleaning device 60 of the secondary transfer device 52 passes from the front side F to the rear side R of the image forming apparatus 1 through the waste toner conveyance path 61 and the waste toner conveyance coupling portion 91, and the main body. The toner is transported to the side waste toner transport unit 90.

  Since electronic devices are densely packed inside the drawer unit 76, the temperature is high overall, but outside air flows into the drawer unit 76 from the opening 93 provided on the exterior side surface. Therefore, the temperature is relatively low from the front side F to the center of the image forming apparatus 1 close to the opening 93, and relatively high from the center to the rear side R where the outside air is difficult to flow from the opening. In particular, the main body side waste toner conveyance unit 90 provided on the rear side R of the image forming apparatus 1 is likely to be high in temperature, and thus needs to be sufficiently cooled to prevent blocking of waste toner.

  As described above, the cooling device 80 includes the both-side suction sirocco fan 81 and the duct 82 and is attached to the base member 77. The duct 82 of the cooling device 80 is provided so as to run in parallel in the longitudinal direction of the secondary transfer device 52 and the waste toner conveyance path 61. The duct 82 has a first exhaust port 87 that guides the airflow to the waste toner transport path 61 and a second exhaust port 88 that guides the airflow to the main body side waste toner transport unit 90. As described above, the duct 82 is arranged in parallel with the waste toner conveyance path 61 of the secondary transfer device 52 in the longitudinal direction, so that it is discharged from the first exhaust port 87 or the second exhaust port 88 of the duct 82. The cooling air is guided in parallel in the longitudinal direction of the waste toner conveyance path 61 without greatly refracting the cooling air, and it is possible to cool a wide range and prevent blocking of the waste toner. In the present embodiment, since the first exhaust port 87 is located near the center in the longitudinal direction of the waste toner transport path 61, the cooling air discharged from the first exhaust port 87 is guided near the center of the waste toner transport path 61, It flows toward the back side.

Further, as described above, the cooling device 80 has a configuration that does not refract the airflow greatly, and therefore it is advantageous in that pressure loss can be suppressed, cooling capacity is increased, and noise is reduced.
If the duct 82 is not arranged in parallel with the waste toner conveyance path 61, it is necessary to refract the airflow greatly, and the pressure loss increases, so that the cooling capacity decreases and the noise increases. Occurs.
Further, by arranging the duct 82 so as to run in parallel in the longitudinal direction of the waste toner conveyance path 61, it is possible to suppress an increase in the size of the entire cooling device.

  The cooling air discharged from the second exhaust port 88 is guided toward the main body side waste toner transport unit 90 located on the back side, and the main body side waste toner transport unit 90 (powder transport unit), which is a cooling target portion, is guided. Cooling. The blocking of the waste toner cannot be prevented by cooling one of the waste toner conveyance path 61 and the main body side waste toner conveyance unit 90, but it is necessary to cool the entire waste toner conveyance path whose temperature rises. For this reason, according to the conventional cooling device, it is necessary to dispose the cooling device in each of the waste toner conveyance path 61 and the main body side waste toner conveyance unit 90, and there has been a problem of increase in size and cost of the device. However, according to the cooling device 80 of the present embodiment, each of the waste toner conveyance path 61 and the main body side waste toner conveyance unit 90 can be simultaneously cooled by one cooling device 80 having a simple configuration. Therefore, it is advantageous in terms of cost, number of parts reduction, downsizing, and low noise.

  In addition, the duct 82 is provided with an inclined portion 82 h that is downstream from the first exhaust port 87 and upstream from the second exhaust port 88 located at the tip, and is inclined downward toward the second exhaust port 88. As a result, the air flow path on the downstream side is narrower than the upstream side, and thus the second exhaust port 88 is also narrowed. The cross section of the air flow path on the downstream side of the inclined portion 82h is narrower than the cross section of the air flow path on the upstream side. The narrower the air flow path, the higher the flow velocity. Therefore, the waste toner is effectively applied by applying strong cooling air to the lower part of the main body side waste toner conveying unit 90 where the waste toner is accumulated by the second exhaust port 88 narrower than the upstream side. It is possible to cool the toner and prevent blocking of waste toner.

  By the way, in this embodiment, the waste toner sent to the main body side waste toner conveyance unit 90 falls to the lower part as shown by the arrow, and is then carried to the back side of the paper surface of FIG. Therefore, by providing the inclined portion 82h, it is possible to effectively cool the lower portion of the main body side waste toner conveyance unit 90 where the waste toner that has fallen is stored, and it is possible to prevent blocking of the waste toner there.

  As described above, the cooling device 80 uses the sirocco fan 81 as an airflow generation source. Since the sirocco fan has a high static pressure, it can guide the cooling air over a wide range with respect to the waste toner conveyance path 61 and the main body side waste toner conveyance unit 90 extending long in the longitudinal direction, and can prevent blocking of the waste toner over a wide range.

FIG. 11 is a diagram illustrating the duct bending portion.
FIG. 11 is a schematic plan view of the cooling device 80 and the main body side waste toner conveyance unit 90. As shown in the figure, in this embodiment, the main body side waste toner conveyance unit 90 extends to the back side of the paper surface of FIG. Therefore, the longitudinal direction of the waste toner conveyance path 61 and the longitudinal direction of the main body side waste toner conveyance unit 90 do not coincide with each other and are in a vertical positional relationship. Further, since the longitudinal direction of the duct 82 coincides with the longitudinal direction of the waste toner conveyance path 61, the direction of the airflow flowing in the duct 82 coincides with the waste toner conveyance path 61. It does not coincide with the longitudinal direction of the unit 90. Further, the main body side waste toner conveyance unit 90 is not positioned in front of the second exhaust port 88 at the downstream portion of the duct 82 of the cooling device 80, and is disposed so as to be shifted from the second exhaust port 88.

  Therefore, a curved portion 82 i that curves toward the main body side waste toner conveyance unit 90 is provided in the vicinity of the second exhaust port 88 in the downstream portion of the duct 82 of the cooling device 80. The curved portion 82 i changes the airflow direction in the longitudinal direction of the main body side waste toner conveyance unit 90, and the cooling air is guided along the longitudinal wall surface 92 of the main body side waste toner conveyance unit 90. Accordingly, it is possible to apply cooling air over a wide range in the longitudinal direction of the main body side waste toner conveyance unit 90 and prevent blocking over a wide range.

FIG. 12 is a cross-sectional view at the center in the longitudinal direction of the secondary transfer apparatus according to the embodiment.
A secondary transfer device 52 as a transfer device according to the present embodiment includes a secondary transfer belt 56 stretched between two support rollers 57, and a belt cleaning device disposed below the support roller 57 on the right side in the drawing. 60 and a waste toner conveyance path 61 provided below the belt cleaning device 60 are integrally formed. The belt cleaning device 60 has a cleaning blade 62 that abuts against the secondary transfer belt 56 in the rotational direction thereof. The toner on the secondary transfer belt 56 is scraped off by the cleaning blade 62 when the secondary transfer belt rotates, and is stored in the lower waste toner conveyance path 61. A waste toner conveyance path 61 that extends linearly in the vertical direction of the drawing and in the front-rear direction of the image forming apparatus 1 is provided with a waste toner conveyance screw 63, and the toner is moved from the front side to the rear side in the figure by the rotation of the waste toner conveyance screw 63. (From the front side of the image forming apparatus 1 to the back side). A conveyance guide 64 for the recording medium is provided on the downstream side (left side) of the secondary transfer device 52 in the conveyance direction, and the recording medium is conveyed to the fixing unit 53 (FIG. 1) by the conveyance guide 64. A cooling device 80 that cools the waste toner transport path 61 is provided below the waste toner transport path 61 of the secondary transfer device 52, and the waste toner transport path 61 is cooled by the air discharged from the first exhaust port 87. .

FIG. 13 is a schematic front sectional view of a cooling device that cools the conveying screw of the photoconductor cleaning device.
An image forming unit 75 configured as an image forming unit integrally includes a unit drum 78 with a photosensitive drum 74, a charging device 79, a developing device 69, a photosensitive member cleaning device 89 as a cleaning device, and the like. It can be detached from the main body 11. In this embodiment, the image forming unit 75 itself as an image forming unit is replaced. However, the individual units of the photosensitive drum 74, the charging device 79, the developing device 69, and the photosensitive member cleaning device 89 are replaced with new ones. It may be exchanged for. A common configuration of each image forming unit 75 (yellow, cyan, magenta, black) will be described in more detail.

  Each image forming unit 75 includes a photosensitive drum 74 that is a latent image carrier, and a charging device 79 that is a charging unit that charges the surface of the photosensitive drum 74. The image forming means 75 supplies toner to the latent image formed by the exposure unit 51 which is a latent image forming means for forming a latent image on the surface of the photosensitive drum 74 charged by the charging device 79 and develops it. A developing device 69 is provided as developing means. Further, the image forming unit 75 transfers the toner image formed by the developing device 69 to the surface of the photosensitive drum 74 after being transferred by the intermediate transfer roller 55 that is a transfer unit that transfers the toner image to the intermediate transfer belt 54 that is a transfer member. A photoconductor cleaning device 89 is provided as toner removing means for removing residual toner. Further, the photoconductor cleaning device 89 includes a pre-cleaning static elimination lamp 95, a fur brush 96 as a rotating brush, a cleaning blade 97, a coating brush 98, and a leveling blade 66 in order from the upstream side in the surface movement direction of the photoconductor drum 74. . In the photoconductor cleaning device 89, the fur brush 96 and the cleaning blade 97 constitute toner removal means. Further, the lubricant supply mechanism is configured by the application brush 98 and the configuration in which the solid zinc stearate 99 held by the bracket is pressed against the application brush 98 by the lubricant pressure spring 68.

  The surface of the photosensitive drum 74 that has transferred the toner image to the intermediate transfer belt 54 at the primary transfer portion, which is the opposite portion between the photosensitive drum 74 and the intermediate transfer roller 55, is discharged by a pre-cleaning discharge lamp 95 and discharged by a fur brush 96. Transfer residual toner is disturbed. As a result, the toner is easily removed by the cleaning blade 97 on the downstream side of the surface movement direction of the photosensitive drum 74. The toner that is powder adhering to the fur brush 96 is flickered by the flicker 65, and the toner blown off is removed from the photoreceptor cleaning device 89 by the waste toner conveyance path 105 (powder conveyance path) provided with the conveyance screw 67. It is designed to be conveyed.

  The surface of the photosensitive drum 74 from which the toner has been removed by the cleaning blade 97 is coated with zinc stearate as a lubricant by a coating brush 98. In the application of zinc stearate, solid zinc stearate 99 held on the bracket is pressed against the application brush 98 by the lubricant pressurizing spring 68, and the application brush 98 scrapes the zinc stearate 99 to remove the photoconductive drum 74. It is applied on the surface.

The coating brush 98 rotates in the counter direction with respect to the surface movement direction of the photosensitive drum 74. The lubricant scraped from the zinc stearate 99 by the application brush 98 and applied onto the surface of the photosensitive drum 74 is in contact with the surface of the photosensitive drum 74 in the counter direction with respect to the surface movement direction of the photosensitive drum 74. Further, it is applied onto the photosensitive drum 74 in a dense manner by a fixed pressure type leveling blade 66 supported on the photosensitive drum 74.
In each image forming unit 75, the transfer residual toner on the photosensitive drum 74 is removed in this way, and a lubricant is applied to prepare for the next image formation starting from uniform charging by the charging device 79.

  As shown in FIG. 13, guide guides 101 and 102 for inserting and removing the unit frame 78 from the apparatus main body are arranged on both sides of the unit frame 78. The guide guides 101 and 102 extend in the front-rear direction of the apparatus, and the user can insert and remove the unit frame 78 and the image forming means 75 along the guide guides 101 and 102.

  The cooling device 80 of the present embodiment is disposed in the space 103 formed by the cutout portion of the unit frame 78 and the protruding portion of the guide guide 102, and is a cross-sectional view taken along the line CC of FIG. As shown, an air current is blown to the waste toner conveyance path 105 provided with the conveyance screw 67 and the main body side waste toner conveyance unit 90 to cool. The cooling device 80 has the same configuration as that of the above-described embodiment, and the longitudinal direction of the conveying screw 67 without greatly refracting the cooling air discharged from the first exhaust port 87 or the second exhaust port 88 of the duct 82. Can be guided in parallel and can be cooled in a wide range. Also with the cooling device 80 of the present embodiment, each of the conveying screw 67 and the main body side waste toner conveying unit 90 can be simultaneously cooled by one cooling device having a simple configuration.

FIG. 15 is a schematic front sectional view of a cooling device that cools the conveying screw of the developing device.
The cooling device 80 of the present embodiment is disposed in a space 104 formed by the cutout portion of the unit frame 78 and the protruding portion of the guide guide 101, and as shown in the drawing, air current is supplied to the conveying screws 69a and 69b of the developing device. To cool them. By disposing the cooling device 80 on the developing device 69 side, the developing device 69 can be cooled and aggregation of the developer in the developing device 69 can be suppressed.

1 Image forming device 52 Secondary transfer device (transfer device)
60 Belt cleaning device (cleaning device)
61, 105 Waste toner transport path (powder transport path)
75 Image forming means (image forming unit)
80 Cooling device 81 Both sides suction sirocco fan (source of air flow)
82 Duct 87 First exhaust port 88 Second exhaust port 89 Photoconductor cleaning device (cleaning device)
90 Waste toner transport unit on the main unit side (powder transport unit)

JP-A-8-22237 JP 2010-243678 A

Claims (8)

A powder conveyance path for conveying powder;
A powder transport unit connected to the powder transport path;
A cooling device for cooling the powder conveyance path and the powder conveyance unit,
The cooling device has an airflow generation source and a duct that runs in parallel with the powder conveyance path,
2. The image forming apparatus according to claim 1, wherein the duct has a first exhaust port that guides an airflow to the powder transport path and a second exhaust port that guides the airflow to the powder transport unit.   The image forming apparatus according to claim 1, wherein the duct has an inclined portion that is inclined downward toward the second exhaust port on an upstream side of the second exhaust port located at a tip.   The image forming apparatus according to claim 1, wherein the duct has a curved portion that changes an air flow direction in a longitudinal direction of the powder conveyance unit.   The image forming apparatus according to claim 1, wherein the airflow generation source is a sirocco fan.   The first exhaust port is located corresponding to a flow path expanding portion between a straight path along the air flow from the exhaust port of the air flow generation source and an expanded path wider than the straight path. The image forming apparatus according to any one of claims 1 to 4.   The first exhaust port is located near the center in the longitudinal direction of the duct, the position corresponds to a substantially central portion in the longitudinal direction of the powder conveyance path, and the airflow from the first exhaust port is on the back side of the apparatus. The image forming apparatus according to claim 1, wherein the image forming apparatus is discharged obliquely toward the image forming apparatus.   The exterior of the image forming apparatus main body is provided with an opening for intake of the cooling device, and the air sucked from the opening flows in the longitudinal direction of the front cover and then is perpendicular to the longitudinal direction and the image forming apparatus main body The image forming apparatus according to claim 1, wherein the airflow generation source sucks air from an air inlet of the duct disposed in the front-rear direction. A base member on which the cooling device is installed;
The image forming apparatus according to claim 1, wherein the base member is an upper part that forms a reversal conveyance path for reversing and conveying the recording medium that has passed through the fixing device for duplex printing.

Images