JP4746403B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a printer.

  2. Description of the Related Art Conventionally, in an image forming apparatus in which an image is formed on a sheet supplied from a sheet feeding unit by an image forming unit and a fixing unit and then discharged to a sheet discharging unit, the height of the entrance guide of the fixing unit Is switched by a solenoid and a cooling air passage is formed with respect to the solenoid (see Patent Document 1).

  By the way, in the image forming apparatus as described above, it is conceivable that the fixing unit is attached to the apparatus main body so as to be movable between an external drawing position and an internal storage position to facilitate jamming and the like.

  Further, it is conceivable that the fixing unit is provided with a sheet conveyance switching member that switches the conveyance direction between the upper sheet discharge unit and the side sheet discharge unit, and a solenoid that switches the conveyance switching member.

In such a case, the solenoid needs to be cooled because the self-heating and the installation of the solenoid in the vicinity of the fixing heat source of the fixing unit become high temperature.
Japanese Patent Laid-Open No. 2001-13808

  However, since the fixing unit is pulled out for jamming, etc., it is necessary to increase the safety by covering it with a cover member so that the operator's hand does not touch the high-temperature solenoid. Since it is difficult to secure the air path, there is a problem that cooling is difficult.

  The present invention has been made in order to solve the above-described problem, and is provided with a solenoid that switches the conveyance switching member in a fixing unit that can be pulled out to the outside, and has been devised to satisfy both safety and cooling performance. An object of the present invention is to provide an image forming apparatus.

  In order to solve the above-described problem, the present invention provides an image forming apparatus in which an image is formed on a sheet supplied from a sheet feeding unit by an image forming unit and a fixing unit and then discharged to a sheet discharging unit. The fixing unit is attached to the apparatus main body so as to be movable between an external drawer position and an internal storage position, and the fixing unit includes a conveyance switching member that switches a paper conveyance direction, and the conveyance switching member. And a solenoid that switches between the first position and the second position so that the solenoid protrudes to the ventilation position at the storage position of the fixing unit, and enters a retreat position that does not touch an operator's hand when the fixing unit is pulled out. An image forming apparatus is provided in which a cooling auxiliary member that is linked to the above is attached.

  According to a second aspect of the present invention, a ventilation position is set on the front side of the fixing unit and a retracting position is set on the back side, and the cooling auxiliary member slides on the upper surface of the solenoid in the same direction as the moving direction of the fixing unit. The cooling auxiliary member is attached to the fixing unit and is locked by the locking unit on the apparatus main body side in a state of being biased to the back side by the tension biasing member between the fixing unit, It is preferable that the airflow position is positioned on the front side, and the position where the fixing unit is pulled out is positioned on the back side retracted position.

  According to the present invention, in the case where the fixing unit that can be pulled out is provided with a solenoid that switches the conveyance switching member, the cooling auxiliary member of the solenoid is moved to a retreat position that does not touch the operator's hand in conjunction with the pulling out of the fixing unit. By immersing, the safety is enhanced, and the cooling performance of the solenoid is enhanced by causing the cooling auxiliary member of the solenoid to project to the ventilation position in conjunction with the storage of the fixing unit.

  As in claim 2, the cooling auxiliary member is slidably attached to the upper surface of the solenoid, and may be locked by the locking portion on the apparatus main body side while being urged to the back side by the tension urging member. Therefore, the structure is simple and can be operated reliably.

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

  As shown in FIG. 1, a printer (an example of an image forming apparatus) 1 basically includes an image forming section at a middle position on a sheet supplied from a sheet feeding section 2 at a lower position of a printer main body (apparatus body) 7. After the image is formed by the fixing unit 4 and the fixing unit 4, the image is discharged to the paper discharge unit 5 at the upper position.

  The printer body 7 is provided with left and right frames 8 (only one frame 8 is shown in FIG. 3), and a paper feed cassette 26 described later is detachably stored at a lower position between the left and right frames 8. A space is formed, and the image forming unit 3 and the fixing unit 4 are attached to the middle position between the left and right frames 8.

  The outer periphery of the left and right frames 8 is covered with an exterior cover 10, and the upper openings of the left and right frames 8 are covered with a top cover 11 having a paper discharge unit 5.

  In the image forming unit 3, the peripheral surface of the photosensitive drum 14 that rotates clockwise in the drawing is uniformly charged by the charging device 13, and laser light based on the image data is transferred from the exposure unit (not shown) such as LSU to the photosensitive member. An electrostatic latent image is formed by irradiating the circumferential surface of the drum 14, and toner is supplied from the developing device 16 to the electrostatic latent image formed on the circumferential surface of the photosensitive drum 14, whereby the photosensitive drum 14. A toner image is formed on the peripheral surface.

  Further, the sheet is conveyed from the sheet feeding unit 2 toward the photosensitive drum 14, and the toner image on the surface of the photosensitive drum 14 is transferred to the surface (transfer surface) of the sheet by the transfer roller (transfer device) 18. Become. The toner remaining on the photosensitive drum 14 after the transfer is removed by a cleaning device 20 provided with a cleaning roller, and the remaining charge on the photosensitive drum 14 thereafter is removed by a static eliminator (not shown).

  Then, the sheet separated from the photosensitive drum 14 by the separating device 23 is conveyed to the fixing roller pair 24 of the fixing unit 4, and the sheet on which the toner image is fixed is discharged by the discharge roller pair 25 of the discharge unit 30. The paper is discharged to the paper portion 5.

  The paper feed unit 2 includes a paper feed cassette 26 that is detachably attached to the printer main body 7 and can store a plurality of sheets stacked.

  The paper feed cassette 26 is provided with a pickup roller 27 for taking out the stored paper, and a paper feed roller 28 for sending out (sheeting) the paper taken out by the pickup roller 27 one by one to the transport path. On the upstream side (right side in the drawing) of the photosensitive drum 14 in the conveyance path, a registration roller pair 29 for waiting for the sheet fed from the sheet feeding roller 28 is provided.

  The transport path includes a first transport path 31 for transporting paper from the paper feed cassette 26 toward the photosensitive drum 14, and a second transport for transporting paper from the photosensitive drum 14 toward the fixing roller pair 24. A path 32 and a third transport path 33 for transporting paper from the fixing roller pair 24 toward the discharge roller pair 25 of the discharge unit 30 are provided.

  The first conveyance path 31 rises substantially vertically on the right side of the drawing between the lower position and the middle position of the printer body 7, and extends horizontally toward the left side of the drawing at the middle position so as to reach the photosensitive drum 14. Is arranged.

  The third conveyance path 33 rises while curving substantially perpendicularly from the fixing roller pair 24 on the left side in the figure, on the opposite side of the first conveyance path 31, that is, between the middle position and the upper position of the printer body 7. Has been placed.

  The second transport path 32 is disposed substantially horizontally from the transfer roller 18 to the fixing roller pair 24 at the middle position of the printer body 7 in order to connect the first transport path 31 and the third transport path 33. .

  As shown in FIG. 2, a manual feed tray (paper feed unit) 35 is attached to the right side of the middle position of the printer body 7 as shown in FIG. 2, and a paper discharge tray (paper discharge unit) 36 is attached to the left side of the figure. Installed. The trays 35 and 36 are respectively laid down to the illustrated positions when in use, and are raised up to vertical positions along the right side and left side of the printer body 7 by the hinge when not in use.

  The paper conveyance during the operation of the printer 1 will be described. The paper is taken out from the paper feed cassette 26 of the paper feed unit 2 by the pickup roller 27, and the taken-out paper is fed by the paper feed roller 28 and sent one by one to the first transport path 31. The sheet sent out to the first conveyance path 31 is once put into a standby state by the registration roller pair 29.

  Then, after waiting for the toner image to be formed on the surface of the photoconductive drum 14 and releasing the standby state, the sheet is conveyed toward the photoconductive drum 14 and is disposed to face the photoconductive drum 14. The toner image on the surface of the photosensitive drum 14 is transferred to the surface (transfer surface) of the paper by the transfer roller 18.

  Next, the sheet separated from the photosensitive drum 14 by the separating device 23 is conveyed toward the fixing roller pair 24 through the second conveying path 32. Then, the sheet on which the toner image is fixed by the fixing roller pair 24 is discharged to the paper discharge unit 5 by the discharge roller pair 25 through the third conveyance path 33 (see arrow P in FIG. 6).

  When the manual feed tray 35 and the paper discharge tray 36 are used, when the paper is fed into the manual feed tray 35, the paper is transported from the first transport path 31 toward the photosensitive drum 14, and the toner on the surface of the photosensitive drum 14. The image is transferred to the surface (transfer surface) of the paper, conveyed to the fixing roller pair 24 through the second conveying path 32, and after the toner image is fixed by the fixing roller pair 24, the image is discharged to the paper discharge tray 36. (See arrow P in FIG. 7).

  In order to facilitate the jam processing and the like, the fixing unit 4 is connected to the printer body 7 with respect to the external drawing position (see the arrow OUT) shown in FIGS. 2 and 3B, and FIGS. It is movably attached to the internal storage position (see arrow IN) shown in a).

  That is, as shown in FIG. 2 and FIG. 3B, a rail groove member 40 is attached to the middle position of the left and right frames 8, and a rail member 41 is attached to the fixing unit 4. By fitting 41 into the rail groove members 40 of the left and right frames 8, the fixing unit 4 is supported so as to be able to be pulled out and stored with respect to the printer body 7.

  The fixing unit 4 switches the sheet conveyance direction between a direction in which the sheet is conveyed to the sheet discharge unit 5 (see arrow P in FIG. 6) and a direction in which the sheet is conveyed to the sheet discharge tray 36 (see arrow P in FIG. 7). A conveyance switching member 42 is swingably provided. This conveyance switching member 42 is connected to a plunger 43a of a solenoid 43 provided on the upper portion of the fixing unit 4 as shown in FIG. The switching operation is performed by the operation.

  Since the solenoid 43 at the top of the fixing unit 4 may touch the operator's hand when the fixing unit 4 is pulled out, a plurality of small ventilation holes are provided as shown in FIGS. 4 (a) and 5 (a). The upper part is covered with a cover member 44 formed with 44a.

  The fixing portion 4 at the inner side of the solenoid 43 is provided with a square hole-shaped ventilation duct 45 penetrating in the vertical direction. As shown in FIG. 8, wind a from a fan (not shown) provided on the side of the printer body 7 is supplied to the duct 46 of the fixing unit 4 to cool the peripheral part of the fixing unit 4 and A ventilation duct 45 is opened facing the lower opening of 46, and the wind b branched from the duct 46 is also supplied to the ventilation duct 45.

  As shown in FIGS. 4B and 5B, in the gap between the lower surface of the cover member 44 and the upper surface of the solenoid 43, the upper surface of the solenoid 43 has a metal (for example, aluminum) excellent in heat conduction. The cooling auxiliary member 47 is disposed, and the cooling auxiliary member 47 is attached to the upper surface of the solenoid 43 by a step screw 48 penetrating the elongated hole 47a so as to be slidable in the same direction as the moving direction of the fixing unit 4. ing. In this way, by bringing the cooling auxiliary member 47 into surface contact with the upper surface of the solenoid 43, the heat of the solenoid 43 is conducted to the cooling auxiliary member 47.

  The cooling auxiliary member 47 has a ventilation duct that protrudes into the ventilation duct (ventilation position) 45 from the slit 45a at the storage position of the fixing unit 4 and does not touch the operator's hand when the fixing unit 4 is pulled out. A cooling fin portion 47b is formed so as to immerse in a retracted position outside 45. The cooling fin portion 47b is cooled by the air b supplied to the ventilation duct 45 hitting the cooling fin portion 47b, and the heat of the solenoid 43 is transmitted from the cooling replenishing member 47 to the cooling fin portion 47b side. 43 is cooled.

  That is, a ventilation duct (ventilation position) 45 is set on the front side of the fixing unit 4, and a retreat position is set on the back side of the ventilation duct 45, so that the cooling auxiliary member 47 is stretched between the fixing unit 4. At the storage position of the fixing unit 4, the locking portion 7 a (see FIG. 4A) protrudes from the printer body 7 side while being biased to the back side by the tension spring (tension biasing member) 49. The cooling fin portion 47b is set so as to protrude into the ventilation duct 45 (ventilation position).

  As a result, the cooling fin portion 47b of the cooling auxiliary member 47 is located inside the ventilation duct (ventilation position) 45 on the near side in the storage position of the fixing portion 4, and on the back side in the position where the fixing portion 4 is pulled out. It will be located in the retreat position.

  That is, the cooling assist member 47 is positioned at the ventilation position in conjunction with the storing operation of the fixing unit 4 and is positioned at the retracted position in conjunction with the pulling-out operation of the fixing unit 4.

  In the case of the printer 1, in the fixing unit 4 that can be pulled out to the outside, the solenoid 43 that switches the transport switching member 42 is provided, and the cooling fins of the cooling auxiliary member 47 of the solenoid 43 in conjunction with the pulling out of the fixing unit 4. By immersing the portion 47b in the retreat position outside the ventilation duct 45, the operator's hand is not touched, so that safety is improved.

  Further, by causing the cooling fin portion 47 b of the cooling auxiliary member 47 of the solenoid 43 to protrude to the ventilation position in conjunction with the storage of the fixing unit 4, the cooling performance of the solenoid 43 is enhanced by the heat conduction of the cooling auxiliary member 47. .

  Further, the cooling auxiliary member 47 is slidably attached to the upper surface of the solenoid 43 using a long hole 47a and a stepped screw 48, and is urged to the back side by a tension spring 49, and is connected to the printer main body 7 side. Since it only has to be locked by the stop portion 7a, the structure is simple and can be operated reliably. The cooling auxiliary member 47 can be directly fixed to the printer body 7 without the tension spring 49 and the locking portion 7a. However, by providing the tension spring 49 and the locking portion 7a, the printer body 7 Assembling errors can be suppressed to a minimum, and assembling properties are also improved.

FIG. 2 is a cross-sectional view of the printer according to the embodiment of the present invention, in which the fixing unit is in a storage position. FIG. 2 is a cross-sectional view of the printer of FIG. 1 in which a fixing unit is in a drawer position. 1A is a perspective view of a main part of a fixing unit in a storage position, and FIG. 1B is a perspective view of a main part of a fixing unit in a pull-out position. (A) is a principal part perspective view of the fixing | fixed part of an accommodation position, (b) is a perspective view of the solenoid and cooling auxiliary member of (a). (A) is a perspective view of the main part of the fixing portion at the pull-out position, and (b) is a perspective view of the solenoid and the cooling auxiliary member of (a). FIG. 4 is a cross-sectional view of a main part in which a conveyance switching member swings in a direction in which a sheet is conveyed to a paper discharge unit side. FIG. 6 is a cross-sectional view of a main part in which a conveyance switching member swings in a direction in which a sheet is conveyed to a paper discharge tray side. It is sectional drawing which shows the relationship between a solenoid, a cooling auxiliary member, and a ventilation duct.

Explanation of symbols

1 Printer (image forming device)
2 Paper feeding unit 3 Image forming unit 4 Fixing unit 5 Paper ejection unit 7 Printer body 7a Locking unit 35 Manual feed tray (paper feeding unit)
36 Paper output tray (paper output part)
42 Transfer switching member 43 Solenoid 44 Cover member 45 Ventilation duct 47 Cooling auxiliary member 47b Cooling fin portion 49 Tension spring (tension biasing member)

Claims (2)

In an image forming apparatus in which an image is formed on a sheet supplied from a sheet feeding unit by an image forming unit and a fixing unit and then discharged to a sheet discharging unit.
The fixing unit is attached to the apparatus main body so as to be movable between an external drawer position and an internal storage position, and the fixing unit is configured to switch a conveyance switching member that switches a paper conveyance direction and the conveyance switching member. While the solenoid to be operated is provided, the solenoid is interlocked so that it protrudes to the ventilation position at the storage position of the fixing unit, and enters the retraction position where the operator does not touch the operator at the position where the fixing unit is pulled out. An image forming apparatus having a cooling auxiliary member attached thereto.   A ventilation position is set on the front side of the fixing unit and a retracting position is set on the back side, and the cooling auxiliary member is slidably mounted on the upper surface of the solenoid in the same direction as the moving direction of the fixing unit. The auxiliary member is urged to the back by a tension urging member between it and the fixing unit, and is locked by the locking unit on the apparatus main body side, and is positioned at the front side ventilation position in the storage position of the fixing unit. The image forming apparatus according to claim 1, wherein the image forming apparatus is positioned at a back side retracted position when the fixing unit is pulled out.

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