JP2006330413A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus in which a duct to discharge heat produced in a fixing part outside is configured by using an existing structure. <P>SOLUTION: The image forming apparatus is provided with an image forming part 3 with a laser scanner unit 4 and a fixing part 6 fixing a toner image on paper. A supporting frame 5 supporting the laser scanner unit 4 from below is provided above the fixing part 6. A duct space 55 which is closed on top by a bottom surface of the laser scanner unit 4 and made a closed cross section in profile and a flowing in port 55j having the heated air rising by being heated by the fixing part 6 flow into the duct space 55 are formed in the supporting frame 5. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a printer, a copier, a facsimile machine, and a multifunction machine having these functions.

  Conventionally, as an image forming apparatus, an electrostatic image is formed on a surface of a photosensitive drum by irradiating a laser beam from a laser scanner unit, and further, toner is supplied onto the surface to form a toner image. An image forming unit that transfers a toner image onto a sheet and a fixing unit that fixes the toner image onto a sheet are known.

  The fixing unit generally has a heat roller and a pressure roller, and the toner image is fixed on the paper by heat and pressure by sandwiching the paper on which the toner image is transferred by these rollers. It has become.

Since the temperature of the heat roller is controlled at 170 to 200 ° C., if this heat is transmitted to the image forming unit, there is a possibility that the toner may be solidified. Therefore, heat is transmitted from the fixing unit to the image forming unit. In order to prevent this, a duct member having a plurality of suction ports is arranged above the fixing unit or between the fixing unit and the image forming unit, and the air around the fixing unit is sucked by this duct member to the outside. The heat generated in the fixing unit is released to the outside by discharging it (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 11-231760

  However, separately providing a duct member as described above requires a space for disposing the duct member, and increases the material cost and assembly cost of the duct member.

  Therefore, it is desired to construct a duct using an existing structure.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus in which a duct that releases heat generated in a fixing unit to the outside can be configured using an existing structure.

  The present invention has been made by paying attention to the fact that a support frame for supporting the laser scanner unit from below is disposed above the fixing portion. The invention of claim 1 is provided on the surface of the photosensitive drum. An electrostatic image is formed by irradiating a laser beam from a laser scanner unit, and a toner image is formed by supplying toner thereon, and an image forming unit for transferring the toner image onto a sheet, and the toner image In an image forming apparatus including a fixing unit for fixing to a sheet, a support frame for supporting the laser scanner unit from below is provided above the fixing unit, and the support frame is supported by a bottom portion of the laser scanner unit. A duct space that is closed up and has a closed cross section in a side view, and heated air that is heated by the fixing unit and rises in the duct space. And an inlet for communicating the duct space with the outside is provided on one side of the duct space, and outside air is sent to the duct space on the other side, A fan for sending heated air from the exhaust port to the outside is provided.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, a polygon motor is disposed at the bottom of the laser scanner unit that covers the upper portion of the duct space.

  According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, a partition wall for partitioning the polygon motor side and the inlet side is provided in the duct space. Is.

  According to a fourth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, a duct that connects the duct space and the exhaust port is provided on the other side of the duct space. It is characterized by this.

  According to the first aspect of the present invention, since the inflow port is provided in the support frame located above the fixing unit, the fixing unit is heated by using the rising air flow generated by heating the air around the fixing unit. Heated air can flow into the duct space. Since the heated air that has flowed into the duct space is sent out from the exhaust port by the outside air, heat generated in the fixing unit can be quickly released to the outside. In addition, since the duct space is closed from above at the bottom of the laser scanner unit and has a closed cross section in plan view, the duct can be configured using the laser scanner unit rationally.

  According to the invention of claim 2, it is possible to rationally cool the polygon motor of the laser scanner unit using the outside air sent into the duct space.

  According to the invention of claim 3, the outside air sent into the duct space flows separately into a route for sending out heated air heated in the fixing unit and a route for cooling the polygon motor. Can be sent out without contacting the portion of the laser scanner unit where the polygon motor is disposed, and the heated air can be prevented from being further heated by the heat generated by the polygon motor.

  According to the fourth aspect of the present invention, the direction in which the heated air heated by the fixing unit is sent out can be selected in an arbitrary direction by the duct.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  1 and 2 show a printer which is an image forming apparatus according to an embodiment of the present invention. The present invention is not limited to a printer, but can be applied to other image forming apparatuses such as a copying machine, a facsimile machine, and a multifunction machine.

  The printer forms an image on a sheet based on image data sent from a terminal or the like in the middle of conveying the sheet along the conveyance path L. A photoconductor is provided inside the box-shaped casing 1. An image forming unit 3 that forms a toner image on the surface of the drum 31 and then transfers the toner image to a sheet, a sheet feeding unit 2 that supplies the sheet to the image forming unit 3, and a fixing unit 6 that fixes the toner image to the sheet. And.

  The conveyance path L has a horizontal portion L1 extending substantially horizontally from the front to the rear and a vertical portion L2 rising substantially vertically from the rear end portion of the horizontal portion L1, and has a substantially L shape in a side view. Yes.

  The paper feed unit 2 has a paper feed cassette 21 disposed below the horizontal portion L1 of the transport path L. The paper stored in the paper feed cassette 21 is taken out by the pickup roller 2a, and the paper is Are fed one by one to the horizontal portion L1 of the conveyance path L by the paper feed rollers 2b to 2e, and the sheet fed to the conveyance path L is once waited by the registration rollers 2f and supplied to the image forming section 3 at a predetermined timing. It is supposed to be.

  The paper feed unit 2 also has a manual feed tray 22 attached to the front surface 1d of the housing 1. The paper placed on the manual feed tray 22 is taken out by the pickup roller 2g, and the paper is fed to the paper feed roller. 2c and 2e can be sent to the horizontal portion L1 of the transport path L one by one.

  The image forming unit 3 includes a photosensitive drum 31 disposed substantially at the center in the front-rear direction of the horizontal portion L1 of the conveyance path L, a charging unit 32 disposed above the photosensitive drum 31, and a photosensitive drum. A developing unit 33 disposed in front of the photosensitive drum 31, a transfer unit 34 disposed below the photosensitive drum 31, a cleaning unit 35 disposed behind the photosensitive drum 31, a charging unit 32, and a cleaning unit. And a laser scanner unit (LSU) 4 disposed above the fixing unit 6.

  The photosensitive drum 31 rotates clockwise in FIG. 2, and the surface of the photosensitive drum 31 is uniformly charged by the charging unit 32 and then based on the image data by the laser scanner unit 4. An electrostatic latent image is formed by irradiating laser light from between the charging unit 32 and the developing unit 33, and toner is supplied from the developing unit 33 to the surface on which the electrostatic latent image is formed. A toner image is formed.

  The paper supplied from the paper feeding unit 2 is conveyed while being pressed against the photoconductive drum 31 by the transfer roller 34a of the transfer unit 34, so that the surface of the photoconductive drum 31 is transferred to the surface (transfer surface). The toner image formed on the toner image is transferred and then sent to the fixing unit 6.

  Note that the toner and residual charge remaining on the surface of the photosensitive drum 31 after the transfer are removed by the cleaning unit 35.

  The fixing unit 6 is disposed behind the cleaning unit 35 of the image forming unit 3, and the laser scanner unit 4 is positioned above the fixing unit 6 as described above.

  As shown in FIG. 5, the fixing unit 6 is configured as a unit with an upper housing 61 and a lower housing 62, and a conveyance path L is formed between the upper housing 61 and the lower housing 62. . The upper housing 61 holds a heat roller 6a, and the lower housing 62 holds a pressure roller 6b.

  A front upper guide portion 61a for guiding the paper in the front-rear direction is formed at the front position of the heat roller 6a of the upper housing 61, and the paper is heated at the front position of the pressure roller 6b of the lower housing 62. A front lower guide portion 62a that guides between 6a and the pressure roller 6b is formed, and these guide portions 61a and 62a constitute a part of the horizontal portion L1 of the transport path L.

  The front upper guide portion 61a is reinforced by a plurality of ribs 61c arranged in the left-right direction. Between these ribs 61c, through-holes 61b penetrating the front upper guide portion 61a are formed. Yes. When the surrounding air is overheated by the heat roller 6a, the heated heated air rises from the through hole 61b as shown by an arrow c in the figure.

  On the other hand, at the rear side position of the heat roller 6a of the upper housing 61, there is provided a rear upper guide portion 61d for guiding the paper so that the paper transport direction is changed from backward to upward, and the pressure of the lower housing 62 A rear lower guide portion 62b for guiding the sheet so as to change the conveyance direction of the sheet from the rear side to the upper side is provided at the rear side position of the roller 6b, and these guide units 61d and 62b are arranged horizontally in the conveyance path L. The rear end portion of the portion L1 and the lower end portion of the vertical portion L2 are configured.

  The temperature of the heat roller 6a is controlled at 170 to 200 ° C., and the pressure roller 6b is pressed against the heat roller 6a. The paper onto which the toner image is transferred by these rollers 6a and 6b is used. By sandwiching the toner image, the toner image is fixed on the paper by heat and pressure.

  The paper on which the toner image is fixed is discharged to a discharge portion 1f formed on the upper surface 1a of the housing 1 by discharge rollers 8a and 8b.

  In the printer of the present embodiment, the switchback unit 7 is provided between the horizontal part L1 of the transport path L and the paper feed cassette 21 so that images can be formed on both sides of the paper.

  The laser scanner unit 4 has a box shape that is flat in the vertical direction and has a size extending from the charging unit 32 to the fixing unit 6, and the lower surface 4 a is disposed in a posture that is inclined downward. ing.

  Further, as shown in FIG. 4, the laser scanner unit 4 is configured by covering a container-shaped main body opening upward, with a polygon motor 4c (FIG. 2) in the rear position. Reference) is arranged. In FIG. 4, only the main body of the laser scanner unit 4 is depicted.

  A support frame 5 that supports the laser scanner unit 4 from below is disposed above the charging unit 32, the cleaning unit 35, and the fixing unit 6, and above the charging unit 32, the cleaning unit 35, and the fixing unit 6. Is covered with a support frame 5.

  As shown in FIGS. 6 and 7, the support frame 5 has a substantially rectangular shape in plan view, and has a horizontally long rectangular plate-shaped bottom plate 5a that forms a horizontal surface above the fixing unit 6, and a front end of the bottom plate 5a. A front plate 5b that rises vertically from the rear portion, a rear plate 5c that rises obliquely rearward from the rear end portion of the bottom plate 5a, and obliquely upward from the upper end of the front plate 5b toward the front. An extending inclined portion 5d, a bottom plate 5a and a right side plate 5e rising vertically from the right end of the inclined portion 5d, and a left side plate 5f rising vertically from the left end of the bottom plate 5a and the inclined portion 5d, The container is open.

  The front plate 5b also extends directly below the bottom plate 5a, and serves as a partition that partitions the cleaning unit 35 and the fixing unit 6 of the image forming unit 3 from each other.

  The upper surface of the bottom plate 5a and the inclined portion 5d is provided with a column 5g at an appropriate position, and the laser scanner unit 4 is supported by fixing the fixing portion 4d of the laser scanner unit 4 to the column 5g with a fixing screw. It is supported by the frame 5.

  Further, a rear wall 5i that extends in the left-right direction while being bent so that a central portion in the left-right direction protrudes rearward is provided at a position slightly ahead of the rear end of the bottom plate 5a. A duct space 55 extending in the left-right direction and opening upward is formed by the bottom plate 5a and the front plate 5b.

  The height of the front plate 5b is set so that when the laser scanner unit 4 is supported by the support frame 5, the upper end portion of the front plate 5b contacts the lower surface 4a of the laser scanner unit 4, The height of the rear wall 5 i is set so that the upper end of the rear wall 5 i abuts the rear surface of the laser scanner unit 4. Therefore, when the laser scanner unit 4 is supported by the support frame 5, the duct space 55 is blocked by the bottom of the laser scanner unit 4, that is, the lower surface 4 a and the rear surface 4 b of the laser scanner unit 4, and viewed from the side. It becomes a closed section.

  In addition, heated air that is heated by the heat roller 6a of the fixing unit 6 and rises into the duct space 55 at a position corresponding to the through hole 61b of the front upper guide portion 61a of the fixing unit 6 into the bottom plate 5a. A plurality of inlets 5j are formed side by side in the left-right direction.

  The polygon motor 4c of the laser scanner unit 4 is arranged on the rear side of the inflow port 5j. The upper surface of the bottom plate 5a extends in the left-right direction between the polygon motor 4c and the inflow port 5j. A partition wall 5h that partitions the duct space 55 in the front-rear direction is provided.

  On the left side of the duct space 55, a portion corresponding to the duct space 55 of the left side plate 5f is greatly cut out from above to form a cutout 5k, and the cutout portion 5k is formed into a duct with the cutout portion 5k. While a hood 51 that forms an air inlet leading to the space 55 is attached, as shown in FIG. 3, the left side surface 1 b of the housing 1 is indicated by an arrow “a” in a position corresponding to the hood 51. A fan 11 for sending outside air to the duct space 55 is attached.

  The fan 11 is driven in accordance with an on / off operation of a printer.

  On the right side of the duct space 55, a duct 52 extending in the front-rear direction is attached in the support frame 5. On the left side surface of the duct 52, there are an opening 52a through which the duct space 55 communicates with the front part 55A partitioned by the partition wall 5h, and an opening 52b through which the duct space 55 communicates with the rear part 55B partitioned by the partition wall 5h. On the other hand, as shown in FIG. 7, two through holes 52c and 52d that open the inner space of the duct 52 rearward are formed at the right side position (left side in FIG. 7) of the rear plate 5c. Furthermore, a partition 52e that partitions the internal space of the duct 52 into a substantially L shape in plan view is provided inside the duct 52, and a flow path that connects the front opening 52a and the right through hole 52c; A flow path connecting the rear opening 52b and the left through hole 52d is formed separately.

  As shown in FIG. 3, the rear surface 1e of the housing 1 is provided with an exhaust port 12 at a position corresponding to the through holes 52c and 52d, and the air passing through the duct 52 is shown by an arrow b in the figure. As can be seen, it can be discharged backwards.

  In the printer configured as described above, when the air around the heat roller 6a of the fixing unit 6 is heated by the heat roller 6a, the heated air heated by the rising airflow generated by the heating passes through the front upper guide portion 61a. It flows into the front portion 55 </ b> A of the duct space 55 through the hole 61 b and the inlet 5 j of the support frame 5.

  Note that the front plate 5b of the support frame 5 serves as a partition between the cleaning unit 35 and the fixing unit 6 of the image forming unit 3, so that the heated air is not brought into contact with the cleaning unit 35 and is ducted from the inlet 5j. This can flow into the front portion 55A of the space 55, and the temperature rise of the cleaning unit 35 can be suppressed.

  On the other hand, when the outside air is sent into the duct space 55 by the fan 11, the outside air flows into the front side portion 55A and the rear side portion 55B of the duct space 55 by the partition wall 5h.

  The heated air that has flowed into the front portion 55A of the duct space 55 is sent out into the duct 52 from the opening 52a by the outside air sent into the front portion 55A of the duct space 55, as indicated by an arrow d in FIG. The flow direction is changed from a right direction to a rear direction in a substantially L shape, and is discharged to the outside through the through hole 52c and the exhaust port 12.

  Further, the outside air sent into the rear portion 55B of the duct space 55 absorbs heat generated by the polygon motor 4c through the lower surface 4a of the laser scanner unit 4 as shown by an arrow e in FIG. Then, the air flows into the duct 52 and is discharged to the outside through the through-hole 52d and the exhaust port 12 while changing the flow direction in the duct 52 from right to rearward in a substantially L shape.

  In the printer of this embodiment, since the inlet 5j is provided in the support frame 5 located above the fixing unit 6, the ascending airflow generated by heating the air around the heat roller 6a of the fixing unit 6 is used. Heated air heated by the heat roller 6a can be caused to flow into the front portion 55A of the duct space 55. Since the heated air that has flowed into the front portion 55A of the duct space 55 is sent out from the exhaust port 12 by the outside air, the heat generated in the fixing unit 6 can be quickly released to the outside. In addition, since the duct space 55 is closed from above at the bottom of the laser scanner unit 4 and has a closed cross section in a plan view, the duct can be configured using the laser scanner unit 4 rationally.

  In addition, since the polygon motor 4c is disposed at the bottom of the laser scanner unit 4 that closes the duct space 55, the polygon motor 4c of the laser scanner unit 4 is also used by utilizing the outside air sent into the duct space 55. It becomes possible to cool reasonably.

  Furthermore, since a partition wall 5h that partitions the duct space 55 in the front-rear direction is provided in the duct space 55, the outside air sent into the duct space 55 is heated by the heat roller 6a of the fixing unit 6. Since the flow is divided into a route for sending heated air and a route for cooling the polygon motor 4c, the heated air is sent to the outside without contacting the portion of the laser scanner unit 4 where the polygon motor 4c is arranged. It is possible to prevent the heated air from being further heated by the heat generated by the polygon motor 4c.

  In the above-described embodiment, the exhaust port 12 is provided on the rear surface 1e of the housing 1. However, the exhaust port 12 may be provided on the right side surface 1c of the housing 1. However, if the exhaust port 12 is provided on the rear surface 1e of the housing 1 and the duct 52 that connects the duct space 55 and the exhaust port 12 is provided as in the above-described embodiment, the direction of the hot air discharged from the housing 1 can be determined. It becomes possible to select behind the body 1.

  Further, the laser scanner unit 4 does not have to be disposed in a posture in which the lower surface 4a is inclined, and may be disposed in a posture in which the lower surface 4a is horizontal.

  Further, the upper part of the duct space 55 may be closed only by the lower surface 4 a of the laser scanner unit 4.

  Further, the duct space 55 only needs to extend in the left-right direction and open upward. Even if the duct space 55 is not configured by providing the rear wall 5i on the bottom plate 5a as in the above embodiment, the bottom plate 5a is directed downward. It is also possible to form it by recessing.

1 is a perspective view of a printer according to an embodiment of the present invention. It is a cross-sectional side view of the printer. FIG. 2 is a schematic plan view of the printer. It is a perspective view of the laser scanner unit which abbreviate | omitted the fixing | fixed part, the support frame, and the top plate. It is a perspective view of a fixing unit. It is a perspective view when a support frame is seen from the left front. It is a perspective view when a support frame is seen from the left rear.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Housing | casing 11 Fan 12 Exhaust port 2 Paper feeding part 3 Image formation part 31 Photosensitive drum 4 Laser scanner unit 41 Polygon motor 5 Support frame 5j Inlet 51 Hood 52 Duct 55 Duct space 6 Fixing part 6a Heat roller 6b Pressure roller

Claims (4)

An image is formed on the surface of the photosensitive drum by irradiating a laser beam from a laser scanner unit to form an electrostatic image, and further supplying toner on the surface to form a toner image and transferring the toner image onto a sheet. An image forming apparatus comprising: a fixing unit configured to fix the toner image on a sheet;
A support frame for supporting the laser scanner unit from below is provided above the fixing unit. The support frame is closed by the bottom of the laser scanner unit and has a closed space in a side view. And an inflow port through which heated air that is heated and raised by the fixing unit flows into the duct space is formed,
An exhaust port that communicates the duct space with the outside is provided on one side of the duct space, and a fan that sends outside air to the duct space and sends the heated air to the outside from the exhaust port on the other side. An image forming apparatus comprising:   The image forming apparatus according to claim 1, wherein a polygon motor is disposed at a bottom portion of the laser scanner unit that covers the upper portion of the duct space.   The image forming apparatus according to claim 2, wherein a partition wall that partitions the polygon motor side and the inlet side is provided in the duct space.   The image forming apparatus according to claim 1, wherein a duct that connects the duct space and the exhaust port is provided on the other side of the duct space.

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