JP2005017939A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus that effectively cools the entire apparatus. <P>SOLUTION: A cooling fan 7 for blowing air from the outside of the image forming apparatus into the apparatus is disposed in the side of the apparatus. Three separate air flows 7a, 7b, 7c are created from the cooling fan 7. The first air flow 7a is an air flow led to a boundary between a fixing unit as a heat source, a scanner unit, and a process cartridge by the cooling fan 7, thereby creating a heat insulation layer. The second air flow 7b is an air flow led to a boundary between the scanner unit, the process cartridge, and ejected paper by the cooling fan 7, thereby creating another heat insulation layer. The third air flow 7c is an air flow created by a duct for a power source unit, as a heat source, which is disposed at the same side as and below the cooling fan 7. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus using an electrophotographic system, and relates to an image forming apparatus such as a copying machine, a printer, and a facsimile machine.
[0002]
[Prior art]
FIG. 7 schematically shows an example of a conventional color image forming apparatus using an electrophotographic process, in this example, a color laser printer.
[0003]
This color laser printer includes a process cartridge 2 serving as four image forming portions of yellow 2Y, magenta 2M, cyan 2C, and black 2K. An image carrier 21 (electrophotographic photosensitive member) in each process cartridge 2 is provided. 4) A four-drum type (in-line) printer that obtains a full-color print image by continuously and continuously transferring the image formed on the intermediate transfer member 35, which is a second image carrier.
[0004]
At this time, if the process cartridges 2 are arranged so as to be stacked in the vertical direction, the installation area can be reduced, the merit of saving the office space is great, and it is an effective means for personalizing the color laser printer. .
[0005]
In addition, in order to reduce the installation area of the transfer path of the transfer material P, it is also effective to use an S-path shape that passes through the fixing unit and is discharged to the upper part through the back surface of the scanner unit.
[0006]
[Problems to be solved by the invention]
However, in such a vertical in-line type color printer, a plurality of cooling fans for cooling the entire apparatus are required. As a result, the apparatus is increased in size and cost. In addition, when the fixing unit, which is a heat source as shown in the conventional example, is located below the apparatus, there is a problem that a temperature rise below a specified value cannot be suppressed unless the entire apparatus is efficiently cooled. End up.
[0007]
Further, as shown in the conventional example, when the fixing unit 6 is below the apparatus and the scanner units as exposure apparatuses are arranged vertically, a temperature difference is easily generated between the units, which causes color misregistration. Therefore, there arises a problem that the image quality is lowered.
[0008]
SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus that can efficiently cool the entire apparatus.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, the present invention has the following means.
[0010]
That is, in the image forming apparatus of the present invention, at least a plurality of process cartridges including an electrophotographic photosensitive member that is detachably attached to the main body of the image forming apparatus are arranged in the vertical direction so as to face the electrophotographic photosensitive member in the process cartridge. An intermediate transfer member suspended from the intermediate transfer member is disposed on the opposite side of the intermediate transfer member, and a fixing unit is disposed below the scanner unit. In the image forming apparatus having a downstream sheet conveyance path of the fixing unit on the back side of the scanner unit section and discharged to the upper part of the scanner unit section and the process cartridge,
A cooling fan for blowing air from outside the image forming apparatus into the image forming apparatus is provided on a side surface of the image forming apparatus, and an air flow from the cooling fan is divided into three parts;
The first airflow forms a heat insulation layer by the airflow led from the cooling fan at the boundary between the fixing unit, which is a heat source, the scanner unit, and the process cartridge,
The second airflow forms a heat insulation layer by the airflow led from the cooling fan at the boundary between the scanner unit and the process cartridge and the discharged paper,
The third airflow can realize efficient cooling of the entire apparatus by providing a power source unit as a heat source below the same side as the cooling fan and forming an airflow by a duct.
[0011]
In the image forming apparatus of the present invention, a drive source serving as a heat source is disposed on the opposite side of the cooling fan on the downstream side of the first air flow, and the opposite of the cooling fan on the downstream side of the second air flow. A configuration in which a drive source that is a heat source different from the drive source is arranged on the side can also be exemplified, and according to this illustration, further effective cooling of the entire apparatus can be realized.
[0012]
In the image forming apparatus of the present invention, at least a plurality of process cartridges including an electrophotographic photosensitive member that is detachably attached to the main body of the image forming apparatus are arranged in the vertical direction so as to face the electrophotographic photosensitive member in the process cartridge. An intermediate transfer member suspended from the intermediate transfer member is disposed on the opposite side of the intermediate transfer member, and a fixing unit is disposed below the scanner unit. In the image forming apparatus having a downstream sheet conveyance path of the fixing unit on the back side of the scanner unit section and discharged to the upper part of the scanner unit section and the process cartridge,
A cooling fan that blows air from the outside of the image forming apparatus into the image forming apparatus is provided substantially above the scanner unit part on the side of the image forming apparatus, and a main air flow is directed to the scanner unit part. By forming from the upper side to the lower side in an oblique direction, it is possible to reduce the temperature difference between the scanner unit portions, and it is possible to solve the problem of image quality degradation such as color misregistration.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are intended to limit the technical scope of the present invention only to those unless otherwise specified. It is not a thing. Moreover, in the following drawings, the same number is attached | subjected to the member similar to the member described in drawing used by description of the above-mentioned prior art.
[0014]
[Overall Description of Image Forming Apparatus]
First, the overall configuration of the color image forming apparatus will be schematically described with reference to FIG. FIG. 7 is an explanatory diagram of the overall configuration of a laser printer which is an embodiment of a color image forming apparatus.
[0015]
The color laser printer is developed in an image forming unit having a process cartridge 2 (2Y, 2M, 2C, 2K) having an image carrier 21 rotating at a constant speed for each color of Y, M, C, and K. It comprises an intermediate transfer body 35 that holds the multiple transferred color image and further transfers it onto the transfer material P fed from the feeding section.
[0016]
The transfer material P onto which the color image has been transferred is conveyed to the fixing unit 6 to fix the color image on the transfer material P, and is discharged onto the discharge tray 56 on the upper surface of the apparatus by a discharge roller group 53.45.55. The four-color process cartridges 2 are individually detachable from the printer body.
[0017]
Next, the configuration of each part of the image forming apparatus will be sequentially described in detail.
[0018]
[Image carrier]
An image carrier (photosensitive drum) 21 (21Y, 21M, 21C, 21K) is integrally formed with a developer container 24 (24Y, 24M, 24C, 24K), and this process cartridge 2 (2Y, 2M, 2C, 2K) is detachably supported with respect to the printer main body, and is configured so that the unit can be easily replaced in accordance with the life of the image carrier 21. An image carrier (photosensitive drum) 21 according to the present embodiment is configured by coating an organic photoconductor layer on the outside of an aluminum cylinder, and is rotatably supported by a container 24 of the image carrier 21.
[0019]
Further, by transmitting the driving force of a driving motor (not shown) to one end on the rear side in the drawing, the image carrier 21 is rotated counterclockwise in the drawing according to the image forming operation.
[0020]
[Charging means]
The charging means 23 (23Y, 23M, 23C, 23K) uses a roller charging method and uniformly charges an applied voltage on the surface of the image carrier 21 by a charging roller.
[0021]
[Exposure means]
The image carrier 21 is exposed from the scanner unit 1 (1Y, 1M, 1C, 1K). When the image signal is given to the laser diode, the laser diode irradiates the polygon mirror 11 (11Y, 11M, 11C, 11K) with the image light 10 (10Y, 10M, 10C, 10K) corresponding to the image signal.
[0022]
The polygon mirror 11 is rotated at a high speed by a scanner motor 12 (12Y, 12M, 12C, 12K), and the image light 10 reflected by the polygon mirror 11 passes through the imaging lens 13 (13Y, 13M, 13C, 13K) at a constant speed. The surface of the rotating image carrier 21 is selectively exposed to form an electrostatic latent image on the image carrier 21 as a result.
[0023]
[Development means]
The developing means is composed of four process cartridges 2 that can develop each color of yellow, magenta, cyan, and black in order to visualize the electrostatic latent image. Each of the four color process cartridges 2 faces the image carrier 21 and is disposed at a position where the sleeve 22 (22Y, 22M, 22C, 22K) contacts the image carrier 21 while rotating. A visible image is formed with each color toner.
[0024]
[Intermediate transfer member]
The intermediate transfer member 35 rotates in the clockwise direction in synchronism with the outer peripheral speed of the image carrier 21 in order to multiplex-transfer the toner image on the image carrier 21 visualized by each developing device 2 during the color image forming operation.
[0025]
The toner image formed on the image carrier 21 is arranged at a position opposed to the image carrier 21 with the intermediate transfer member 35 interposed therebetween, and the primary transfer roller 34 (34Y, 34M, 34C, 34K) to which a voltage is applied. Multiple transfer is performed on the intermediate transfer body 35 at the primary transfer portion T1 (T1Y, T1M, T1C, T1K) which is a contact.
[0026]
The intermediate transfer body 35 that has undergone multiple transfer sandwiches and conveys the transfer material P by the secondary transfer roller 51 to which a voltage is applied in the secondary transfer portion T2, thereby transferring each color toner image on the intermediate transfer body 35 to the transfer material P. Simultaneous multiple transfer.
[0027]
The intermediate transfer member (intermediate transfer belt) 35 according to the present embodiment is formed of a seamless resin belt having a circumferential length of about 620 mm, and is stretched around three axes of a drive roller 31, a secondary transfer counter roller 32, and a tension roller 33. Thus, both ends of the tension roller 33 are loaded with springs, and even if the peripheral length of the intermediate transfer belt 35 changes due to temperature and humidity in the main body and changes with time, the amount of change can be absorbed.
[0028]
A guide rib (not shown) made of rubber is affixed to the entire circumference of one side edge portion inside the intermediate transfer member 35 with an adhesive. Further, a flange (not shown) made of resin is disposed at one end of the tension roller 33, and a guide rib (not shown) and a flange (not shown) are connected to the traveling direction of the intermediate transfer body 35. It regulates the movement in the direction that goes straight (hereinafter referred to as “slip”).
[0029]
The intermediate transfer member 35 is supported by the main body with the driving roller 31 as a fulcrum, and the driving force of a driving motor (not shown) is transmitted to one end of the driving roller 31 at the rear of the drawing, so that the intermediate transfer member 35 is subjected to image forming operation. It is made to rotate clockwise in the figure.
[0030]
[Paper Feeder]
The paper feed unit feeds the transfer material P to the image forming unit, and includes a cassette 4 containing a plurality of transfer materials P, a paper feed roller 41, a separation pad 42, a paper feed guide 43, and a registration roller pair 44. Mainly composed. At the time of image formation, the paper feed roller 41 is driven and rotated in accordance with the image forming operation, and the transfer material P in the cassette 4 is separated and fed one by one, guided by the guide plate 43, and registered via the conveyance roller. 44. During the image forming operation, the registration roller 44 performs a non-rotating operation for causing the transfer material P to stand still and a rotating operation for conveying the transfer material P toward the intermediate transfer body 35 in a predetermined sequence, and is the next step. The image and the transfer material P are aligned in the transfer process.
[0031]
[Transfer section]
The transfer unit is composed of a swingable transfer roller 51. The transfer roller 51 has a metal shaft wound with a medium resistance foamed elastic body, is movable in the vertical direction in the figure, and has a drive. In accordance with the timing of transferring the color image to the transfer material P, the transfer roller 51 is pressed against the intermediate transfer body 35 by a cam member (not shown) at an upper position, that is, via the transfer material P.
[0032]
At the same time, a bias is applied to the transfer roller 51 and the toner image on the intermediate transfer member 35 is transferred to the transfer material P. Here, since the intermediate transfer body 35 and the transfer roller 51 are respectively driven, the transfer material P sandwiched between the two is transported at a predetermined speed in the left direction in the drawing at the same time as the transfer process is performed. It is conveyed by the belt 52 toward the fixing unit 50 which is the next process.
[0033]
[Fixing part]
The fixing unit 6 fixes the toner image formed on the transfer material P via the intermediate transfer body 35 with the toner image formed by the developing means, and a ceramic heater 63 for applying heat to the transfer material P is provided. It comprises a built-in film guide unit 61 and a pressure roller 62 for pressing the transfer material P against the film guide unit 61. That is, the transfer material P holding the toner image is conveyed by the film guide unit 61 and the pressure roller 62, and the toner is fixed to the transfer material P by applying heat and pressure.
[0034]
[Image forming operation]
Next, an operation when image formation is performed by the apparatus configured as described above will be described.
[0035]
First, the sheet feeding roller 41 shown in FIG. 7 is rotated to separate one transfer material P in the sheet feeding cassette 4 and conveyed to the registration roller 44.
[0036]
On the other hand, the image carrier 21 and the intermediate transfer member 35 rotate in the direction indicated by the arrow at a predetermined outer peripheral speed V (hereinafter referred to as process speed).
[0037]
The image carrier 21 whose surface is uniformly charged by the charging means 23 is subjected to laser 10 exposure to form an image.
[0038]
(1: Formation of yellow image)
The scanner unit 1Y irradiates a yellow image with a laser 10Y to form a yellow latent image on the image carrier 21Y. Simultaneously with the formation of the latent image, the yellow developing unit 22Y is driven to apply a voltage having the same polarity as the charged polarity of the image carrier 21Y so that yellow toner adheres to the latent image on the image carrier 21Y. Develop. At the same time, the yellow toner image on the image carrier 21 is primarily transferred onto the outer periphery of the intermediate transfer member 35 at the first transfer position T1Y downstream of the developing unit. At this time, primary transfer is performed by applying a voltage having a reverse characteristic to that of the yellow toner to the intermediate transfer member 35.
[0039]
(2: Formation of magenta image)
Next, irradiation of the laser 10M of the magenta image is started by the scanner unit 1M so that the tip of the yellow image on the outer periphery of the intermediate transfer member 35 coincides, and the magenta toner image is developed on the latent image on the image carrier 21M in the same manner as yellow. Then, the magenta toner image on the image carrier 21M is transferred onto the intermediate transfer member 35 at the first transfer position T1M.
[0040]
(3: Cyan image formation)
Next, the laser 10C irradiation of the cyan image is started by the scanner unit 1C so that the outer peripheral yellow of the intermediate transfer member 35 and the leading edge of the magenta image coincide with each other, and a cyan toner image is formed on the latent image on the image carrier 21C in the same manner as magenta. The developed cyan toner image on the image carrier 21C is transferred onto the intermediate transfer member 35 at the first transfer position T1C so as to overlap the yellow and magenta toner images.
[0041]
(4: Formation of black image)
Next, the scanner unit 1K starts laser 10K irradiation of the black image so that the leading edges of the yellow / magenta / cyan image on the outer periphery of the intermediate transfer member 35 coincide with each other, and the black toner is applied to the latent image on the image carrier 21K in the same manner as cyan. The image is developed, and the black toner image on the image carrier 21K is further transferred onto the intermediate transfer member 35 at the first transfer position T1K.
[0042]
The latent image formation and development and toner transfer to the intermediate transfer member 35 are performed at the primary transfer positions T1Y, T1M, T1C, and T1K in the order of yellow, magenta, cyan, and black, and the surface of the intermediate transfer member 35 is yellow. Thus, a full-color image composed of four types of toners of magenta, cyan, and black is formed.
[0043]
Before the transfer of the black toner to the intermediate transfer body 35 is completed, that is, before the leading edge of the intermediate transfer body 35 that has formed the full color image after the primary transfer of the black toner of the fourth color reaches the second transfer portion T2. In addition, the transfer material P that has been waiting by the above-described registration roller 44 is transported at the same timing.
[0044]
At the time of image formation of each color on the four-color intermediate transfer member 35, the transfer roller 51, which waits downward and is not in contact with the intermediate transfer member 35, is simultaneously moved upward by a cam (not shown) to transfer material. At the same time that P is pressed by the second transfer portion T2 of the intermediate transfer body 35, a bias having a reverse characteristic to that of the toner is applied to the transfer roller 51, so that a full color image on the intermediate transfer body 35 is simultaneously transferred to the transfer material P in four colors. To do.
[0045]
The transfer material P that has passed through the second transfer portion T2 is peeled off from the intermediate transfer body 35, conveyed to the fixing portion 50, and after toner fixing, the image is transferred onto the discharge tray 56 at the top of the main body via the discharge roller pairs 53, 54, and 55. The sheet is discharged with the surface facing downward, and the image forming operation is completed.
[0046]
FIG. 1 is a schematic cross-sectional view showing the position of a cooling fan in the entire apparatus that best represents the configuration of the present invention.
[0047]
FIG. 2 is a schematic perspective view for explaining the first air flow by the cooling fan.
[0048]
FIG. 3 is a cross-sectional view for explaining a second air flow by the cooling fan.
[0049]
FIG. 4 is a schematic perspective view for explaining the second air flow by the cooling fan.
[0050]
FIG. 5 is a schematic perspective view for explaining a third air flow by the cooling fan.
[0051]
Moreover, FIG. 6 is a figure showing the mode of the duct member for attaching to a cooling fan and dividing an air path into three.
[0052]
The cooling fan 7 is a portion extending from the scanner unit 1 group to the paper discharge path path 58 and is provided on the upper side as the entire apparatus. As shown in FIG. 6, the air sucked from the outside by the cooling fan 7 is divided into three paths (air flows) 7a, 7b, and 7c by a fan duct 71 attached to the cooling fan 7 (FIG. 6 (c)).
[0053]
A first airflow 7a shown in FIGS. 1 and 2 is a mainstream airflow, and is an airflow that blows obliquely downward between the scanner unit 1 group and the paper discharge path 58. The second airflow 7b shown in FIG. 3 and FIG. 4 is an airflow that blows to the lower part of the tray 56 on which the discharged paper on the upper side of the apparatus is stacked.
[0054]
The third airflow 7c is an airflow that is blown to the relay duct 73 connected to the power supply unit 83 that is a heat source on the same side as the cooling fan 7.
[0055]
The first air flow will be further described.
[0056]
A duct (fan duct) 71 serving as an air curtain for separating the fixing unit 6 which is the largest heat source of the entire apparatus, the scanner unit 1 and the cartridge 2 is provided at the tip of the air flow. In addition, a conveyance motor 81 that is a drive source of a sheet conveyance system, which is another heat source, is located at the tip of the air curtain duct 71.
[0057]
As the entire air flow, the air taken in from the cooling fan 7 passes through the air curtain duct 71, cools the transport motor 81, and is then discharged outside the apparatus.
[0058]
The scanner unit 1 and the cartridge 2 are insulated by the heat insulation layer formed by the air curtain duct 71 formed by the air blown from the cooling fan 7, and the temperature rise can be suppressed.
[0059]
Further, since the air flow from the cooling fan 7 flows through the relay duct 72 in an oblique direction from the upper side to the lower side, the temperature of the upper scanner unit 1 is increased by the heat of the fixing unit 6 as it is. As a result, the temperature difference between a group of scanner units can be kept small by lowering the air with fresh air from above. As a result, the color shift due to the temperature difference caused by the scanner unit 1 can be suppressed.
[0060]
Moreover, since the conveyance motor 81 which is another heat source can be simultaneously cooled on the downstream side of the air curtain duct 71, the cooling efficiency is also good.
[0061]
Note that the heat discharged from the fixing unit 6 which is the largest heat source in the apparatus is discharged from the opening 57 above the fixing unit and the paper discharge port 59 by natural convection.
[0062]
Next, the second airflow 7b will be described.
[0063]
The air taken into the upper part of the apparatus almost in parallel from the cooling fan 7 passes below the tray 56 on which the discharged paper is stacked and flows forward in the apparatus. At this time, the exhaust heat accumulated above the cartridge area is also performed.
[0064]
In addition to the air flow that flows to the front of the apparatus, the image forming motor 82 can be cooled by flowing air to the image forming motor 82 for image formation, which is another heat source on the opposite side of the cooling fan on the apparatus. Do.
[0065]
By this second air flow 7b, a heat insulation layer is formed by the circulation of the fresh air between the discharged paper stack as a heat source and the temperature rise in the machine can be suppressed. Further, by arranging an image forming motor 82 as another heat source at the tip of the second air flow 7b, the cooling efficiency is also improved.
[0066]
Finally, the third airflow 7c will be described.
[0067]
Air taken into the lower part of the apparatus from the cooling fan 7 by the fan duct 71 is taken in from the rear of the power supply unit 83 through the relay duct 73 and exhausted from the front of the power supply unit 83 to the outside of the machine through the inside of the power supply unit 83. . This air flow can also efficiently cool the power supply unit 83 serving as a heat source.
[0068]
In the present embodiment, the description has been made with a clear air duct member. However, if the air flow can be secured between the members, the same effect can be obtained without the duct member.
[0069]
Moreover, this invention is not limited to the above-mentioned embodiment, The following technical thought is included and all the combinations of these technical thought are included.
[0070]
[Embodiment 1]
In other words, in the image forming apparatus according to the first embodiment, a driving source serving as a heat source is disposed on the downstream side of the first air flow and on the opposite side of the cooling fan, and the cooling fan is disposed on the downstream side of the second air flow. By disposing a drive source that is a heat source different from the drive source on the opposite side, it is possible to realize further effective cooling of the entire apparatus. Also in this case, since a minimum fan configuration is required, the cost can be reduced and the entire apparatus can be reduced in size.
[0071]
[Embodiment 2]
In the image forming apparatus according to the second embodiment, at least a plurality of process cartridges including an electrophotographic photosensitive member that is detachably attached to the main body of the image forming apparatus are arranged in the vertical direction, and the electrophotographic photosensitive member in the process cartridge is disposed on the electrophotographic photosensitive member in the process cartridge. An intermediate transfer member suspended at an opposing position is arranged, a scanner unit as an exposure device is arranged on the opposite side of the intermediate transfer member across the process cartridge, and a fixing unit is arranged below the scanner unit. In the image forming apparatus having a downstream sheet conveyance path of the fixing unit on the back side of the scanner unit section and being discharged to the upper part of the scanner unit section and the process cartridge,
A cooling fan that blows air from outside the image forming apparatus into the image forming apparatus is provided substantially above the scanner unit on the side of the image forming apparatus, and the air flow from the cooling fan is divided into three parts. And
The first air flow forms a heat insulation layer by an air flow that is led obliquely downward from above the scanner unit part by the cooling fan at the boundary between the fixing unit as a heat source, the scanner unit part, and the process cartridge. ,
The second airflow forms a heat insulation layer by the airflow led from the cooling fan at the boundary between the scanner unit and the process cartridge and the discharged paper,
The third airflow can realize efficient cooling of the entire apparatus by providing a power source unit as a heat source below the same side as the cooling fan and forming an airflow by a duct.
[0072]
[Embodiment 3]
Further, the image forming apparatus according to the third embodiment is the image forming apparatus according to the second embodiment, wherein a driving source serving as a heat source is disposed on the opposite side of the cooling fan on the downstream side of the first air flow. By disposing a drive source which is a heat source different from the drive source on the opposite side of the cooling fan on the downstream side of the air flow, it is possible to realize further effective cooling of the entire apparatus. Also in this case, since a minimum fan configuration is required, the cost can be reduced and the entire apparatus can be reduced in size.
[0073]
In the above-described embodiment, a full-color copying machine is cited as an example of the configuration of the image forming apparatus. However, the present invention is not limited to this, and the image forming apparatus includes an image forming apparatus such as a printer, a facsimile, or a monochrome copying machine. Is also applicable.
[0074]
Further, as the image forming means, an electrophotographic image forming means, an ink jet image forming means, a bubble jet (registered trademark) image forming means, and the like can be applied, but the invention is not limited thereto. Thermal transfer recording methods, thermal recording methods, and wire dots can be applied.
[0075]
【The invention's effect】
As described above, according to the configuration of the present invention, at least a plurality of process cartridges including an electrophotographic photosensitive member detachably attached to the image forming apparatus main body are arranged in the vertical direction, An intermediate transfer member suspended at a position facing the electrophotographic photosensitive member is disposed, and a scanner unit as an exposure device is disposed on the opposite side of the intermediate transfer member with the process cartridge interposed therebetween, and below the scanner unit In the image forming apparatus, the fixing unit is disposed on the back side of the scanner unit section, and has a downstream sheet conveyance path of the fixing unit, and is discharged to the upper part of the scanner unit section and the process cartridge. A cooling fan that blows air from outside into the image forming apparatus is provided on the side of the image forming apparatus. The air flow from the cooling fan is divided into three, and the first air flow is led from the cooling fan to the boundary between the fixing unit, which is a heat source, the scanner unit, and the process cartridge. A heat insulation layer is formed by airflow, and a second airflow forms a heat insulation layer by the airflow guided by the cooling fan at the boundary between the scanner unit and the process cartridge and the discharged paper. The air flow of 3 can provide efficient cooling of the entire apparatus by providing a power source unit as a heat source below the same side of the cooling fan and forming an air flow by a duct. As a result, a minimum fan configuration is required, which can lead to cost reduction and downsizing of the entire apparatus.
[0076]
Further, according to the configuration of the present invention, at least a plurality of process cartridges including an electrophotographic photosensitive member that is detachably attached to the image forming apparatus main body are arranged in the vertical direction so as to face the electrophotographic photosensitive member in the process cartridge. An intermediate transfer member suspended from the intermediate transfer member is disposed on the opposite side of the intermediate transfer member, and a fixing unit is disposed below the scanner unit. In the image forming apparatus having a downstream sheet conveyance path of the fixing unit on the back side of the scanner unit section and discharged to the upper part of the scanner unit section and the process cartridge, air from outside the image forming apparatus is A cooling fan that blows into the image forming apparatus is provided on the side surface of the image forming apparatus. On the other hand, it is provided substantially upward, and the main airflow is formed obliquely downward from above with respect to the scanner unit part, so that it is possible to reduce the temperature difference between the scanner unit parts, Problems such as image quality degradation such as color misregistration can also be solved.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing a position of a fan and a first air flow of an image forming apparatus according to an embodiment of the present invention.
FIG. 2 is a schematic perspective view showing a position of a fan and a first air flow of the image forming apparatus according to the embodiment of the present invention.
FIG. 3 is a schematic cross-sectional view showing a position of a fan and a second air flow of the image forming apparatus according to the embodiment of the present invention.
FIG. 4 is a schematic perspective view showing a position of a fan and a second air flow of the image forming apparatus according to the embodiment of the present invention.
FIG. 5 is a schematic perspective view showing a position of a fan and a third air flow of the image forming apparatus according to the embodiment of the present invention.
6A and 6B are schematic cross-sectional views showing shapes of a fan and a fan holder of the image forming apparatus according to the embodiment of the present invention. FIG. 6B is a cross-sectional view taken along line AA in FIG. It is BB sectional drawing of).
FIG. 7 is a schematic sectional view showing a conventional example and an image forming apparatus according to an embodiment of the present invention.
[Explanation of symbols]
1 Scanner unit (scanner part)
2 Process cartridge
4 Paper cassette
6 Fixing part
7 Cooling fan
7a Airflow
7b Airflow
7c Airflow
10 Laser (image light)
11 Polygon mirror
12 Scanner motor
13 Imaging lens
21 Image carrier
22 Developer
23 Charging means
24 containers
31 Drive roller
32 Secondary transfer counter roller
33 Tension roller
34 Primary transfer roller
35 Intermediate transfer belt
41 Paper feed roller
42 Separation pad
43 Paper feed guide
44 Registration Roller
51 Transfer roller
52 Conveyor belt
53 Discharge roller group
56 Discharge tray
57 opening
58 Output path
59 Paper exit
61 Film guide unit
62 Pressure roller
63 Ceramic heater
71 Air curtain duct (fan duct)
72 Relay duct
73 Relay duct
81 Transport motor
82 Image motor
83 Power supply unit
P transfer material
T1 First transfer section
T2 Second transfer section

Claims (2)

At least a plurality of process cartridges including an electrophotographic photosensitive member that is detachably mounted on the image forming apparatus main body are arranged in a vertical direction, and an intermediate transfer member suspended at a position facing the electrophotographic photosensitive member in the process cartridge is provided. And a scanner unit portion, which is an exposure device, is disposed on the opposite side of the intermediate transfer member across the process cartridge, a fixing unit is disposed below the scanner unit portion, and the scanner unit portion is disposed on the back side of the scanner unit portion. In the image forming apparatus having a sheet conveyance path downstream of the fixing unit and discharged to the upper part of the scanner unit and the process cartridge,
A cooling fan for blowing air from outside the image forming apparatus into the image forming apparatus is provided on a side surface of the image forming apparatus, and an air flow from the cooling fan is divided into three parts;
The first airflow forms a heat insulation layer by the airflow led from the cooling fan at the boundary between the fixing unit, which is a heat source, the scanner unit, and the process cartridge,
The second airflow forms a heat insulation layer by the airflow led from the cooling fan at the boundary between the scanner unit and the process cartridge and the discharged paper,
The third airflow is an image forming apparatus characterized in that a power supply unit serving as a heat source is provided below the same side as the cooling fan to form an airflow by a duct. At least a plurality of process cartridges including an electrophotographic photosensitive member that is detachably mounted on the image forming apparatus main body are arranged in a vertical direction, and an intermediate transfer member suspended at a position facing the electrophotographic photosensitive member in the process cartridge is provided. And a scanner unit portion, which is an exposure device, is disposed on the opposite side of the intermediate transfer member across the process cartridge, a fixing unit is disposed below the scanner unit portion, and the scanner unit portion is disposed on the back side of the scanner unit portion. In the image forming apparatus having a sheet conveyance path downstream of the fixing unit and discharged to the upper part of the scanner unit and the process cartridge,
A cooling fan that blows air from the outside of the image forming apparatus into the image forming apparatus is provided substantially above the scanner unit part on the side of the image forming apparatus, and a main air flow is directed to the scanner unit part. An image forming apparatus, wherein the image forming apparatus is formed obliquely downward from above.

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