JP2007293060A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of using air flows in the apparatus, thereby supplying air to areas that need to be cooled. <P>SOLUTION: An air flow toward a fixing device 41 is separated into an air flow along a first ventilation path 71 and an air flow along a second ventilation path 72. The air flow along the first ventilation path 71 passes between the wall 46c of a frame 46 and the erect part 24 of a case and is blown onto an ejection roller 44. The air flow along the second ventilation path 72 passes through the notched part of the frame 46 and is blown onto the ejection roller 44. This makes it possible to cool the ejection roller 44 as well as the fixing device 41 on the side of a pressure roller 41b. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus using an electrophotographic system such as a copying machine, a printer, a facsimile machine, or a multifunction machine of these.

In an image forming apparatus such as a copying machine or a printer to which an electrophotographic system is applied, for example, an electrostatic latent image formed on a photosensitive drum is developed by a developing device (developer) using a developer, and the photosensitive member is developed. A toner image is formed on the drum, and the toner image formed on the photosensitive drum is transferred and fixed onto a recording medium conveyed from the paper feeding unit to form an image. .
In such an image forming apparatus, air is caused to flow through the hollow portion of the hollow cylindrical guide that guides the recording paper, and the recording paper is adsorbed on the guide surface by sucking air from the slit formed on the guide surface, A configuration for stably transporting recording paper has been proposed (see, for example, Patent Document 1).
In order to prevent dew condensation on the guide plate that guides the recording paper, a configuration in which a through hole is formed in the movable branch member that branches the conveyance path in the double-sided printing mechanism and the air is ventilated has been proposed (for example, see Patent Document 2). ).

Japanese Patent Laid-Open No. 06-24071 Japanese Patent Laid-Open No. 2001-316018

  The image forming apparatus includes a member (for example, a fixing device) that generates various kinds of heat. In some cases, an electronic component (for example, a sensor) that requires countermeasures against heat must be disposed in the vicinity of such a heat generating member. In such a case, in order to suppress an increase in the size of the device, It is necessary to efficiently cool electronic components with the simplest possible configuration. Such cooling is preferably performed with air. However, effective solutions in such a case are not disclosed in Patent Documents 1 and 2 described above. To explain further, Patent Document 2 only discloses a configuration for cooling the entire conveyance path of the recording paper, and it cannot cool by blowing air to an arbitrary member to be cooled.

  The present invention has been made to solve the technical problems as described above, and an object of the present invention is to supply air to a place that needs to be cooled using the air flow inside the apparatus. It is an object of the present invention to provide an image forming apparatus capable of performing the above.

  For this purpose, the image forming apparatus to which the present invention is applied includes a fixing unit that fixes the toner image transferred to the recording medium, and the recording medium on which the toner image is fixed by the fixing unit is discharged from the paper discharge unit. An image forming apparatus for paper, which includes a feeding unit that takes air into the apparatus and sends the air in a direction in which the fixing unit is installed, a paper discharge roller disposed on an air flow path by the feeding unit, and a feeding unit A first ventilation path for blowing air from the fixing unit to the discharge roller through the vicinity of the fixing unit before the fixing unit, and for blowing air by the feeding unit to the discharge roller through the vicinity of the lower side of the fixing unit. A second ventilation path.

  The air guided to the sheet discharge roller by the first ventilation path and the second ventilation path is exhausted from the sheet discharge unit. In addition, the air guided to the paper discharge roller by the first ventilation path is blown to the recording medium that has passed through the fixing unit. In addition, the air guided to the paper discharge roller by the second ventilation path is blown to the recording medium that has passed through the fixing unit.

  From another point of view, an image forming apparatus to which the present invention is applied includes a fixing unit that fixes a toner image transferred to a recording medium. The recording medium on which the toner image is fixed by the fixing unit is provided with a discharge roller. An image forming apparatus for discharging air from a paper discharge unit, a fan for taking air into the apparatus, a duct for branching the flow of air taken into the apparatus by the fan in a plurality of directions, and branched by the duct Cooling means for guiding a part of the air to the fixing unit and then guiding the air to the paper discharge roller to cool the fixing unit and the paper discharge roller, and the cooling unit allows the air to pass through substantially the entire circumference of the fixing unit. Thus, the fixing unit is cooled, and the discharge roller is cooled by blowing air onto the discharge roller.

  The duct may be characterized in that the air is branched so that the image forming unit that forms the toner image transferred to the recording medium is cooled by a part of the air. Further, the cooling means may be characterized in that the electronic component located on the upstream side of the fixing unit in the air flow is cooled. Further, the cooling means may be characterized in that a part of the air is guided so as to pass between the electronic component disposed adjacent to the fixing unit and the fixing unit. In addition, the air by the cooling unit is discharged from the paper discharge unit.

  According to the present invention, it is possible to supply air to a place that needs to be cooled using the air flow inside the apparatus.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 is a schematic configuration diagram showing an image forming apparatus according to the present embodiment.
The image forming apparatus 10 shown in FIG. 1 is a so-called tandem type in which a photosensitive cartridge (image forming unit) 30 is disposed in a main body 11. The photosensitive cartridge 30 includes photosensitive drums (image carriers) 31a, 31b, 31c, which form toner images for yellow (Y), magenta (M), cyan (C), and black (K). 31d. These photosensitive drums 31a to 31d are sequentially arranged in the vertical direction, and various electrophotographic devices are sequentially disposed around each of the photosensitive drums 31a to 31d. As this device, a charging roller 32 that precharges the photosensitive drums 31a to 31d, and electrostatic latent images formed on the photosensitive drums 31a to 31d charged by the charging roller 32 with corresponding toners. There is a developing device 33 for developing, and a cleaning device 34 for removing waste toner on the photosensitive drums 31a to 31d.

  An exposure device (ROS) 12 is disposed adjacent to the photoreceptor cartridge 30. The exposure device 12 deflects and scans light from four semiconductor lasers (not shown) that are driven to light based on image data corresponding to each color by a polygon mirror (not shown), and passes through an fθ lens (not shown) and a plurality of reflection mirrors. Thus, the optical image is guided to the exposure points on the photosensitive drums 31a to 31d.

  A conveyance path 13 through which a sheet (recording material, recording medium) P is conveyed from a substantially vertical lower side to an upper side is disposed at a corresponding portion of the photosensitive drums 31a to 31d. Below the photosensitive cartridge 30 (upstream side), a paper feed cassette 14 for storing paper P is disposed. In addition, due to the size of the paper P stored in the paper feed cassette 14, a part of the paper feed cassette 14 protrudes to the back side (rear side, in side) of the main body 11, and the paper P is small. If it is size, it does not protrude from the main body 11.

  As the paper supply system, in addition to paper supply by the paper feed cassette 14, paper supply by a single manual feed unit 20 can be selected. That is, the image forming apparatus 10 is configured to be able to feed paper P other than the paper P stored in the paper feed cassette 14 from the manual feed unit 20. The manual feed unit 20 is integrated with the paper feed cassette 14 and is configured to set the paper P one by one. Then, when a user instructs a control device (not shown), one of the paper P in the paper feed cassette 14 and the paper in the manual feed tray (not shown) is sent out at a predetermined timing. More specifically, the delivered paper P is transported to the transport path 13 via a plurality of transport rollers 21 and is sent to each transfer position of the photoreceptor cartridge 30 via the transport belt 15.

A conveyance belt 15 that circulates along the conveyance path 13 is disposed at locations corresponding to the photosensitive drums 31a to 31d. The transport belt 15 is made of a belt material capable of electrostatically adsorbing the paper P, and is stretched around a pair of driving roller 16 and driven roller 17. Further, an adsorption roller 18 for electrostatically adsorbing the paper P on the conveyance belt 15 is disposed in the conveyance path 13.
Further, a transfer roller 19 is disposed on the back side of the conveyance belt 15 corresponding to the photosensitive drums 31a to 31d. The transfer roller 19 is for transferring the toner images formed on the photosensitive drums 31a to 31d onto the paper P by bringing the photosensitive drums 31a to 31d and the paper P on the transport belt 15 into close contact with each other.

  A fixing device (fixing unit, fixing unit) 41 is provided in the conveyance path 13 above (downstream side) of the photoconductor cartridge 30. In the upper part of the main body 11, a paper discharge unit 42 serving as an opening for discharging the paper P to the outside of the apparatus, and a paper discharge tray 43 that stores the paper P discharged from the paper discharge unit 42 are provided. ing. The paper discharge unit 42 is provided with a discharge roller (paper discharge roller) 44 and a pinch roller 45 for discharging the paper on which the toner image has been fixed by the fixing device 41 to the paper discharge tray 43. The discharge roller 44 and the pinch roller 45 are disposed to face each other. Note that the pinch rollers 45 are arranged at predetermined intervals in the axial direction (perpendicular to the paper surface).

  An intake fan (feeding means) 61 is disposed on the back side of the image forming apparatus 10. The intake fan 61 is for taking in air from outside the apparatus and supplying air into the apparatus. The air or air flow generated by the intake fan 61 is used to cool each part inside the apparatus. This will be described later.

FIG. 2 is a view for explaining opening and closing of the front cover 22.
As shown in FIG. 2, the main body 11 of the image forming apparatus 10 is provided with a front cover 22 that is rotatable about a rotation fulcrum J provided below. The front cover 22 functions as an external cover together with the main body 11 in the closed state. That is, the front cover 22 constitutes a side wall portion on the upper side (front side, out side) of the image forming apparatus 10 above the paper feed cassette 14.

  Conveying belt 15, driving roller 16, driven roller 17, suction roller 18 and transfer roller 19 are attached to front cover 22. Therefore, when the front cover 22 is opened, these components are accompanied and separated from the main body 11 side. Therefore, by opening the front cover 22, the photosensitive drums 31a to 31d side of the photosensitive cartridge 30 is exposed, and the user can easily access the transport path 13.

  For this reason, by opening the front cover 22 of the main body 11, it is possible to perform the attaching / detaching operation of the photoconductor cartridge 30. By removing the photosensitive cartridge 30 from the main body 11, a toner cartridge (not shown) can be inserted and removed from the side opposite to the photosensitive drums 31a to 31d. A set detection sensor (not shown) detects whether the photoconductor cartridge 30 is set in the main body 11 and outputs the detection result to a control device (not shown).

  In this way, the front cover 22 can be opened to expose a part of the photoconductor cartridge 30 for replacement. Further, it is possible to deal with a jam (clear jam) by exposing the photosensitive drums 31a to 31d. Thus, the maintainability of the image forming apparatus 10 is improved.

Returning to FIG. 1, the description will be continued.
As shown in FIG. 1, the image forming apparatus 10 includes a case 23 as an exterior body of the main body 11. A part of the upper surface of the case 23 is inclined so as to go downward as it approaches the paper discharge unit 42, and the portion configured in this way is the paper discharge tray 43 described above. That is, the paper discharge tray 43 is formed on a slope facing the paper discharge unit 42. In addition, the case 23 has a standing portion 24 that stands up from the lowest position of the paper discharge tray 43 and reaches the paper discharge portion 42.

Here, the fixing device 41 includes a heating roller 41a and a pressure roller 41b. The rollers 41a and 41b of the fixing device 41 are attached to a frame 46 (see FIG. 3). The operation of the fixing device 41 will be briefly described. The sheet P conveyed by the conveying belt 15 is pressed against the heating roller 41a with a predetermined pressure by the pressure roller 41b. As a result, the toner resin of the toner image held on the paper P is heated and melted and fixed on the paper P.
The fixing device 41 includes a thermostat 47 (see FIG. 3) and a harness 48 (see FIG. 3) of the thermostat 47 for dealing with a rapid temperature rise of the heating roller 41a, and these are provided on the frame 46 (see FIG. 3). It is attached.

  The image forming apparatus 10 includes a duct (feeding means) 62 disposed close to the blowing side of the intake fan 61. The duct 62 is for branching the air flow from the intake fan 61 into two. That is, the duct 62 has a blowout port 62 a for guiding the air flow toward the fixing device 41 and a blowout port 62 b for guiding the air flow toward the photosensitive cartridge 30.

  The air flow from the outlet 62a of the duct 62 is directed to the fixing device 41 while passing through the gap inside the device, and then discharged from the paper discharge unit 42 to the outside of the device. More specifically, the air flow blown out from the blowout port 62 a cools the base 63 positioned on the upstream side of the fixing device 41. That is, the air flow first cools the base 63 and then cools the fixing device 41. The base 63 is an electronic component for controlling power-related matters.

  The air flow from the outlet 62 b of the duct 62 is guided to the developing device 33 of the photosensitive cartridge 30. This will be described below. The developing device 33 is affected by heat from, for example, an exposure lamp or a charging lamp disposed in the vicinity thereof. Further, in the developing device 33, the developer is stirred inside the developing device 33, so that the housing of the developing device 33 and the developer inside are heated by heat generated by the friction of the carrier. When the developing device 33 is heated more than necessary, there is a problem that a charging failure of the developer occurs or the toner is solidified under the influence of heat. There is also a problem that the toner image forming action is hindered due to a decrease in toner fluidity. For this reason, in this embodiment, the developing device 33 is also cooled by sending an air flow.

  As shown in FIG. 1, a UI 49 (operation panel) is disposed in the vicinity of the fixing device 41. The UI 49 is attached to the front cover 22. When the front cover 22 is closed, the UI 49 is separated from the fixing device 41 by a predetermined distance. That is, a gap is formed between the fixing device 41 and the UI 49.

  An actuator 50 is disposed on the downstream side of the fixing device 41 in the transport path 13. The actuator 50 is rotatable about a fulcrum 50 a and is disposed so as to cross the conveyance path 13. The width direction dimension of the actuator 50 is smaller than the width dimension of the transport path 13. That is, the conveyance path 13 is not blocked over the entire width direction of the conveyance path 13 by the actuator 50 but only a predetermined portion in the width direction. When the paper P on which the toner image has been fixed by the fixing device 41 is discharged from the paper discharge unit 42, the actuator 50 is operated and retracts from the transport path 13.

FIG. 3 is a perspective view showing the periphery of the fixing device 41.
As shown in FIG. 3, the frame 46 has notches 46 a and 46 b. That is, the notches 46a and 46b are disposed below the vertical wall of the frame 46, thereby forming an air flow passage. In this manner, a flow path is formed around the frame 46 for the air flow from the outlet 62a to flow to the paper discharge unit 42. The flow path includes a first ventilation path 71 formed between the wall portion 46c of the frame 46 and the standing portion 24 of the case 23, and the frame 46 after passing through the notches 46a and 46b of the frame 46. There is a second ventilation path 72 from the space between the UI 49 and the discharge roller 44. In other words, the first ventilation path 71 is a passage for blowing an air flow on the discharge roller 44 through the vicinity of the fixing device 41 before the fixing device 41. The second ventilation path 72 is a path through which the air flow passes around the fixing device 41 and is blown to the discharge roller 44. As described above, the air flow is configured to pass through the vicinity of the fixing device 41 over substantially the entire circumference of the fixing device 41.

The air flow toward the fixing device 41 is branched into a first ventilation path 71 and a second ventilation path 72. The air flow branched to the first ventilation path 71 travels between the wall portion 46 c of the frame 46 and the standing portion 24 of the case 23 and is blown to the discharge roller 44. Therefore, the fixing device 41 on the heating roller 41a side can be partially cooled and the discharge roller 44 can be cooled.
On the other hand, the air flow branched to the second ventilation path 72 is blown to the discharge roller 44 through the notches 46 a and 46 b of the frame 46. For this reason, the fixing device 41 on the pressure roller 41b side can be partially cooled and the discharge roller 44 can be cooled. The air flow through the first ventilation path 71 and the second ventilation path 72 is discharged from the paper discharge unit 42.

  More specifically, when the paper P on which the toner image is fixed by the fixing device 41 is discharged from the paper discharge unit 42 via the discharge roller 44, the first ventilation path 71 and the second ventilation path 72. Each air flow is also blown onto the paper P. Since the second ventilation path 72 crosses the transport path 13, the air flow may be temporarily blocked by the paper P in the transport path 13. In the first ventilation path 71, there is no such blockage of the air flow.

  According to the present embodiment, the discharge roller 44 is cooled by the air flow, and the sheet P immediately after fixing is also cooled by the air flow. Therefore, even when the separation distance between the fixing device 41 and the discharge roller 44 is short, it is avoided that the roll mark is generated by the paper P on which the toner image is fixed being pressed by the discharge roller 44 and the pinch roller 45. it can. For this reason, the image forming apparatus 10 can be easily downsized. Moreover, since the stay of the air around the fixing device 41 can be prevented, the heat resistance level of the components used can be lowered, and the cost increase can be suppressed.

  Thus, in this embodiment, the air flow around the fixing unit can be improved. Further, by creating an air flow in front of the discharge roller 44, it is possible to improve the image defect of the sheet immediately after fixing.

1 is a diagram illustrating an overall configuration of an image forming apparatus to which the exemplary embodiment is applied. It is a figure for demonstrating opening and closing of a front cover. FIG. 2 is a perspective view showing the periphery of a fixing device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Image forming apparatus, 11 ... Main body, 13 ... Conveyance path, 22 ... Front cover, 23 ... Case, 24 ... Standing part, 30 ... Photosensitive cartridge, 41 ... Fixing device, 42 ... Paper discharge part, 43 ... Ejection Paper tray, 44 ... discharge roller, 45 ... pinch roller, 46 ... frame, 46a, 46b ... notch, 46c ... wall, 49 ... UI, 61 ... intake fan, 62 ... duct, 62a, 62b ... outlet, 71 ... 1st ventilation path, 72 ... 2nd ventilation path, P ... Paper

Claims (9)

An image forming apparatus that includes a fixing unit that fixes a toner image transferred to a recording medium, and that discharges the recording medium on which the toner image is fixed by the fixing unit from a paper discharge unit.
Feeding means for taking air into the apparatus and sending the air in the direction in which the fixing unit is installed;
A paper discharge roller disposed on the air flow path by the feeding means;
A first ventilation path for blowing air from the feeding means to the discharge roller through the vicinity of the fixing unit before the fixing unit;
A second ventilation path for blowing air from the feeding means to the discharge roller through the vicinity of the lower side of the fixing unit;
An image forming apparatus including:   The image forming apparatus according to claim 1, wherein the air guided to the paper discharge roller by the first air flow path and the second air flow path is exhausted from the paper discharge unit.   The image forming apparatus according to claim 1, wherein the air guided to the paper discharge roller by the first ventilation path is blown to the recording medium that has passed through the fixing unit.   The image forming apparatus according to claim 1, wherein the air guided to the paper discharge roller by the second ventilation path is blown to the recording medium that has passed through the fixing unit. An image forming apparatus that includes a fixing unit that fixes a toner image transferred to a recording medium, and that discharges the recording medium on which the toner image is fixed by the fixing unit from a paper discharge unit via a paper discharge roller,
A fan that takes air into the device,
A duct for branching the flow of air taken into the apparatus by the fan in a plurality of directions;
Cooling means for guiding a part of the air branched by the duct to the fixing unit and then guiding the air to the paper discharging roller to cool the fixing unit and the paper discharging roller;
Including
The cooling unit cools the fixing unit by allowing air to pass through the vicinity of substantially the entire circumference of the fixing unit, and cools the discharge roller by blowing air to the discharge roller. An image forming apparatus.   The image forming apparatus according to claim 5, wherein the duct branches the air so that an image forming unit that forms a toner image transferred to a recording medium is cooled by a part of the air.   The image forming apparatus according to claim 5, wherein the cooling unit cools an electronic component located upstream of the fixing unit in an air flow.   The image forming apparatus according to claim 5, wherein the cooling unit guides part of the air so as to pass between an electronic component disposed adjacent to the fixing unit and the fixing unit.   The image forming apparatus according to claim 5, wherein air from the cooling unit is exhausted from the paper discharge unit.

Images