Patent Application
20130101310
This application is based on Japanese Patent Application No. 2011-233859 filed on Oct. 25, 2011, the contents of which are incorporated herein by reference.
1. Technical Field
The present invention relates to an image forming apparatus.
2. Description of Related Arts
In an image forming apparatus such as a copying machine, printer, or facsimile machine, a toner image transferred onto printing paper is fixed under heat and pressure while the paper is passing through a fixing member. The paper on which the image is fixed then leaves the fixing member and is discharged to the outside of the image forming apparatus.
When the toner image transferred on the printing paper is heated and pressed, it occurs sometime that the toner melts to cause the paper to stick to the fixing member. In particular, it becomes more difficult to separate the paper from the fixing member when the paper is thin or when a large amount of toner is used. In order to prevent the sheet from sticking to the fixing member, an image forming apparatus typically has a paper separating means for separating the printing paper from the fixing member. For example, the Japanese Unexamined Publication No. 2009271345 discloses an image forming apparatus that separates the printing paper, on which the image is fixed, from the fixing member by blowing air to the paper on the fixing member.
However, in the image forming apparatus of the above-mentioned Japanese Unexamined Publication No 2000-271345, the air blown on to the paper and heated by the fixing member flows along the fixing member to disperse into the inside of the image forming apparatus. As a result, each constituting member of the image forming apparatus located in the vicinity of the fixing member may get damaged by the heat. The present invention was made to solve such a problem. The object of the present invention is to provide an image forming apparatus capable of suppressing the air heated by the fixing member from getting dispersed into the inside of the image forming apparatus.
To achieve at least one of the above-mentioned objects, an image forming apparatus reflecting one aspect of the present invention comprises: a fixing part equipped with a fixing member that transports a sheet of paper on which a toner image is transferred while heating and pressing the sheet of paper in order to fix the image and a blowing part that blows air to a nipping part of said fixing member; a drawer that electrically connects said fixing part with the main unit of said image forming apparatus; a case member that communicates with said fixing part and contains said drawer; and an exhaust duct that conducts the air inside said case member to the outside of said image forming apparatus, wherein said case member is equipped with an opening on one side thereof facing said exhaust duct for conducting the air inside said case member to said exhaust duct.
Said case member is preferably equipped with an opening on another side of said case member.
Said image forming apparatus preferably further comprises an exhausting part for sucking the air inside said exhaust duct and discharging it to the outside of said image forming apparatus.
The objects, features, and characteristics of this invention other than those set forth above will become apparent from the description given herein below with reference to preferred embodiments illustrated in the accompanying drawings.
The embodiments of this invention will be described below with reference to the accompanying drawings.
The first embodiment of the present invention will be described below with reference to
As shown in
The image scanning part 10 scans the image of the document and stores it. The image scanning part 10 is equipped with a light source 11, an optical system 12, an imaging element 13, and an image processing circuit 14.
The light radiating from the light source 11 is reflected from a document P placed on a scanning plane 15, and the reflected light focuses via a lens and a reflection mirror of the optical system 12 on an imaging element 13 that is now moved to the scanning position. The imaging element 13 generates electric signals depending on the intensity of the light reflected from the document P. The generated electric signals are treated by a compensation process, a filtration process, an image compression process, and the like after having been converted from analog signals to digital signals in the image processing circuit 14, and are stored in the memory of the image processing circuit 14 as image data.
The image forming part 20 forms images by means of the electrophotographic process. The image forming part 20 of the present embodiment comprises an image forming part 20Y that forms an yellow (Y) color image, an image forming part 20M that forms a magenta (M) color image, an image forming part 20C that forms a cyan (C) color image, and an image forming part 20K that forms a black (K) color image. Here the common code 20 is followed by another code, Y, M, C, or K, which signifies the color of the corresponding signal.
The image forming part 20Y consists of a rotary member, i.e., a photoreceptor drum 1Y, a charging part 2Y provided on the periphery thereof an optical writing part 3Y. a developing device 4Y, and a drum cleaner 5Y. The photoreceptor drum 1Y rotates at a specified speed driven by a drum motor.
Similarly, the image forming part 20M consists of a charging part 2M provided on the periphery of the photoreceptor drum 1M, an optical writing part 3M, a developing device 4M, and a drum cleaner 5M. Also, the image forming part 20C consists of a charging part 2C provided on the periphery of the photoreceptor drum 1C, an optical writing part 3C, a developing device 4C, and a drum cleaner 5C. Also, the image forming part 20K consists of a charging part 2K provided on the periphery of the photoreceptor drum 1K, an optical writing part 3K. a developing device 4K, and a drum cleaner 5K.
The photoreceptor drums 1Y, 1M, 1C, and 1K, the charging parts 2Y, 2M, 2C, and 2K, the optical writing parts 3Y, 3M, 3C, and 3K, the developing devices 4Y, 4M, 4C, and 4K, as well as the drum cleaners 5Y, 5M, 5C, and 5K, all of which corresponding to the image forming parts 20Y, 20M, 20C, and 20K respectively are constituted with identical components. Therefore, they are sometimes treated in the following descriptions without specific codes Y, N, C, and K when it is not necessary to show their distinctions.
The image forming part 20 forms a latent image on the photoreceptor drum 1 by writing image information signals on the photoreceptor drum 1 with the optical writing part 3 based on the image data stored in the memory of the image processing circuit 14. The latent image is developed by the developing device 4 to form a toner image as a visible image on the photoreceptor drum 1.
Yellow (Y), magenta (M), cyan (C), and black (K) images are formed on the photoreceptor drums 1Y, 1M, 1C, and 1K of the image forming parts 20Y, 20M, 20C, and 20K respectively.
An intermediate transfer belt 21 is supported and driven to go around continuously by a plurality of rollers. The toner image of each color formed by the image forming parts 20Y, 20M, 20C, and 20K respectively is transferred one by one onto the running intermediate transfer belt 21 by means of the primary transfer parts 7Y, 7M, 7C, and 7K to form a color image consisting of Y (yellow), M (magenta), C (cyan), and K (black) color layers overlaid one on top of each other.
The paper transport part 30 transports the printing paper S. The printing paper S is stored in a paper supply tray 51, 52 or 53 of the paper supply part 50. The paper transport part 30 is equipped with a release roller 31, a handling roller 32, a transport roller 33, a loop roller (intermediate roller) 34, a resist roller 35, a paper discharge roller 36, and a paper turning part 37.
The printing papers is sent out from the paper supply tray 51, 52, or 53 by means of the release roller 31 and separated into individual sheets by the handling roller 32. The printing paper S separated into individual sheets is transferred to a secondary transfer roller 22 via a loop roller 34 and a resist roller 35 along a transfer route by means of the transport roller 33.
The color image on the intermediate transfer belt 21 is transferred onto the printing paper S. The fixing part 40 applies heat and pressure on the printing paper S on which the color image is transferred to fix the toner image, after which the printing paper s is discharged via the paper discharge roller 36 to the outside of the image forming apparatus 100.
The image forming apparatus 100 is equipped with the paper turning part 37 so that it can guide the printing paper S on which the fixation is completed from a fixation transport roller 46 to the paper turning part 37 to have it flipped over before discharging it. Thus it is capable of forming images on both sides of the printing paper S.
The fixing part 40 has a heating roller 41, a pressure roller 42, a blower fan 43, a nozzle 44, and a fixing-side connecting part 45.
The heating roller 41 heats the printing paper S on which the toner image is transferred while it is being transported. The heating roller 41 is formed by coating the surface of a cylindrically formed core metal made of aluminum, iron and other metals with a mold releasing layer containing fluorine resins such as PFA (perfluoroalkoxy), PTFE (polytetrafluoroethylene), etc. The heating roller 41 contains a heating part such as a halogen heater. In case of the present embodiment, the heating roller 41 rotates clockwise as shown by the arrow in the drawing.
The pressure roller 42 applies pressure to the printing paper S on which the toner image is transferred while it is being transported. The pressure roller 42 is formed by coating a cylindrically formed core metal made of stainless and other metals with an elastic layer containing a foaming agent such as silicon rubber and a mold separating layer. The pressure roller 42 applies pressure from underneath energized by an energizing member (not shown). In the meanwhile a nipping member N is formed as the pressure roller 42 makes a pressuring contact with the heating roller 41. The pressure roller 42 rotates counterclockwise opposite to the rotation of the heating roller 41. As such, the heating roller 41 and the pressure roller 42 function as the members of the fixing unit and apply heat and pressure to the printing paper S on which the toner image is transferred simultaneous with the transportation of the printing paper S.
The blower fan 43 sends out a specified amount of air towards the nozzle 44. In the present embodiment, the blower fan 43 functions as a blowing part and is controlled to rotate at a specified speed by the control part 80. A sirocco fan, for example, can be used as the blower fan 43.
The printing paper S on which the toner image is transferred is sent into the nipping part N of the fixing part 40 thus constituted. The printing paper S sent into the nipping part N advance from the paper outlet port of the nipping part N toward the fixation transport roller 46 after the image is fixed by means of the heating roller 41 and the pressure roller 42 simultaneous with its transportation. On the other hand, in the nozzle 44, the air sent out from the blower fan 43 increases its speed as it is compressed inside the nozzle 44 and is ejected toward the printing paper S at the paper outlet of the nipping part N. Consequently, the printing paper S is separated from the heating roller 41.
Moreover, in the present embodiment, the fixing part 40 can be removed from the image forming apparatus 100 to be replaced. By moving the fixing pat 40 towards the frontal side of the paper in
The main-unit-side connecting part and the fixing side connecting part are described below referencing
As shown in
The fixing side connecting part 45 has motors that drive the heating roller 41 and the pressure roller 42, a drive circuit that drives the motors, power supply wiring that supplies power to the particular drive circuit and the heater of the heating roller 41, and control signal wiring for controlling constitutions such as the drive circuits and other constituents of the fixing part 40. These and other circuits and wiring are contained in a case.
As shown in
The main-unit-side connecting part 60 has a power circuit and power supply wiring for supplying power from the main unit of the image forming apparatus 100 to the fixing part 40, and a communication circuit and communication wiring for sending and receiving electrical signals between the main unit of the image forming apparatus 100 and the fixing part 40.
Moreover, the main-unit-side connecting part 60 has a drawer 61 that electrically connects the fixing part 40 with the main unit of the image forming apparatus 100. More specifically, the drawer 61 is equipped with an electric contact part (connectors) that electrically connects wiring such as power supply wiring of the main-unit-side connecting part 60 and the fixing side connecting part 45 and communication wiring.
The power circuit, power supply wiring, communication circuit, communication wiring, drawer 61 and other items of the main-unit-side connecting part 60 are contained in a case member 62. The inside of the case member 62 communicates with the inside of the fixing part 40 and the fixing side connecting part 45. The case member 62 has a rectangular shape and is made of a metallic material with an excellent heat dissipation characteristic.
As shown in
The number of openings H and their positions to be formed on the case member 62 are not limited specifically. It is preferable that the number of the openings H is as many as possible from the standpoint of efficiently ventilating the internal air of the main-unit-side connecting part 60. The diameter of the opening H shall be determined considering the protection of the drawer 61 stored in the case member 62 and the efficiency of the air ventilation.
The exhaust part 70 exhausts the air inside the main-unit-side connecting part 60 and the fixing side connecting part 45 to the outside of the image forming apparatus 100. The exhaust part 70 has an exhaust duct 71 and an exhaust fan 72. The exhaust fan 72 functions as an exhaust part and is controlled to rotate at a specified speed by the control part 80.
The exhaust duct 71 is located above the main-unit-side connecting part 60 and the fixing side connecting part 45 separated by a specified distance from the main-unit-side connecting part 60. The entrance 71a of the exhaust duct 71 is located to face against the opening H of the case member 62 so that the air flows out of the opening H enters into the exhaust duct 71 via the entrance 71a of the exhaust duct 71. The air that enters the exhaust duct 71 flows toward the exit 71b of the exhaust duct as it is sucked by the exhaust fan 72. On the other hand, the air that flows out from the fixing side connecting part 45 also enters the exhaust duct 71 via the entrance 71a of the exhaust duct 71 and flows toward the exit 71b of the exhaust duct sucked by the exhaust fan 72.
The control part 80 controls the image scanning part 10, the image forming part 20, the paper transport part 30, the fixing part 40, the paper supply part 50, and the exhaust part 70. The control part 80 is equipped with a CPU (Central Processing Unit), a RAM (Random Access Memory), and a ROM (Read Only Memory). The CPU controls the image scanning part 10, the image forming part 20, the paper transport part 30, the fixing part 40, the paper supply part 50, and the exhaust part 70, and stores the arithmetic results and others on the RAM in accordance with the software program stored in the ROM.
In the image forming apparatus 100 of the present embodiment constituted as described in the above, the air blown to the nipping part N by the blower fan 43 flows in the longitudinal direction of the heating roller 41 and the pressure roller 42, a portion of which flows into the fixing side connecting part 45 and the main-unit-side connecting part 60. The air inside the main-unit-side connecting part 60 flows into the exhaust duct 71 and flows toward the exit 71b of the exhaust duct via the opening H being sucked by the exhaust fan 72. On the other hand, the air that flows out from the fixing side connecting part 45 also enters the exhaust duct 71 and flows toward the exit 71b of the exhaust duct sucked by the exhaust fan 72.
The present embodiment described above provides the following effects:
(a) According to the image forming apparatus 100 of the present invention, the case member 62 that contains the drawer 61 communicates with the fixing part 40, and is equipped with the opening H that conducts the air inside the case member 62 toward the exhaust duct 71 on one side of it that faces the exhaust duct 71. Therefore, the air entering from the fixing part 40 can be efficiently exhausted to the outside of the image forming apparatus 100, so that the air heated by the heating roller 41 can be prevented from dispersing into the inside of the image forming apparatus 100. As a result, each constituting member of the image forming apparatus 100 located in the vicinity of the fixing part 40 can be prevented from getting damaged by the heat.
(b) As the exhaust part 70 is equipped with the exhaust fan 72, the air inside the exhaust duct 71 can be efficiently exhausted to the outside of the image forming apparatus 100.
In the second embodiment, the case member of the main-unit-side connecting part has an opening on another side as well in addition to the side facing the exhaust part. The main-unit-side connecting part of the image forming apparatus according to the second embodiment of the present invention is described referencing
As shown in
In an image forming apparatus equipped with the main-unit-side connecting part 60 constituted as such, if the exhaust fan 72 is not operating, the air blown on to the nipping part N by the blower fan 43 flows along the longitudinal direction of the heating roller 41 and the pressure roller 42, while a portion of which is exhausted directly to the outside of the fixing part 40 via the opening(s) H formed on the case member 62 of the main-unit-side connecting part 60 (refer to the arrows of
On the other hand, if the exhaust fan 72 is operating, the majority of the air existing inside the main-unit-side connecting part 60 flows toward the exit 71b sucked by the exhaust fan 72. Consequently, the amount of air that is exhausted to the outside of the fixing part 40 directly via the opening(s) H is quite limited, if the exhaust fan 72 is operating.
As can be seen from the above, the present embodiment provides the following effects in addition to the effects provided by the first embodiment:
(c) Since the air inside the main-unit-side connecting part 60 is directly exhausted to the outside of the fixing part 40 via the opening(s) H, the stagnation of the air inside the main-unit-side connecting part 60 can be prevented even when the exhaust fan 72 is not operating. Consequently, the drawer 61 can be prevented from being damaged by the heat.
Such is the configurations of the image forming apparatuses according to these embodiments. However, it goes without saying that the present invention can arbitrarily added, modified and omitted by a person skilled in the art within the gist of the technology disclosed herein.
For example, it was described in the first and second embodiments that the air blow onto the nipping part for separating paper from the heating roller is exhausted outside of the image forming apparatus. However, rather than limited to the above-mentioned constitutions, the present invention can be applied to other constitutions where the blowing part is provided inside the fixing part.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-233859 | Oct 2011 | JP | national |
