JP4147019B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrophotographic image forming apparatus such as a copying machine, a laser beam printer, and a facsimile machine.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in an image forming apparatus, output is performed from an exposure unit so that the exposure unit is not contaminated by toner (developer) scattered from a developing area where a photosensitive drum as an image carrier and a developing unit as a developing unit face each other. A partition wall is provided between an irradiation optical path of laser light as an exposure light beam and the developing device. On the other hand, the atmosphere (air) in the apparatus is exhausted by a fan in order to prevent the temperature in the apparatus from rising and the developing unit and the photosensitive drum from overheating. However, since the partition blocks the air flow in the apparatus, the atmosphere having heat in the apparatus may not be exhausted sufficiently. In view of this, an in-machine air passage formation hole is provided in the partition wall to promote exhaust of the atmosphere in the apparatus and prevent overheating of the developing device and the photosensitive drum.
[0003]
Hereinafter, a conventional image forming apparatus will be described with reference to FIGS.
[0004]
The image forming apparatus shown in FIG. 3 has a configuration in which a charging roller 10, a laser scanner unit 4 as an exposure unit, and developing devices Dy and Dm are sequentially arranged along the rotation direction of the photosensitive drum 3 that rotates counterclockwise in the drawing. , Dc, Dk, and a rotary unit 1 as a developing device support member that rotates around a rotation center 1a as an axis, and an intermediate transfer member 6 are disposed.
[0005]
In FIG. 3, when a developing bias is applied to the developing sleeve 2a facing the photosensitive drum 3 in a non-contact manner and carrying a toner thin layer on the surface, the toner jumps from the developing sleeve 2a to the photosensitive drum 3 and development is performed. At this time, the toner cannot completely reach the photosensitive drum 3, and a part of the toner may be scattered and float in the air. The scattered toner may enter the laser irradiation optical path 4c by an air current and adhere to the polygon mirror 4a or the folding mirror 4b, particularly when the rotary unit 1 rotates in the rotation direction 1b (counterclockwise direction in the drawing). . As a result, the output of the laser beam for exposing the photosensitive drum 3 becomes weak, and there is a possibility that image defects such as image thinness and image loss may occur.
[0006]
Therefore, a partition wall 5 is provided between the laser irradiation optical path 4c and the rotary unit 1 so that the toner is not scattered from the developing sleeve 2a to the laser irradiation optical path 4c.
[0007]
On the other hand, since the stacked sheet material 8 discharged to the upper part of the image forming apparatus retains heat due to fixing, the member located below the stacked sheet material 8 may be overheated by radiant heat. When the developing devices Dy, Dm, Dc, Dk and the photosensitive drum 3 are overheated, there is a possibility that the toner solidifies in each developing device (toner blocking) and the power of the photosensitive drum 3 is deteriorated.
[0008]
Here, in order to dissipate radiant heat, a fan 11 that exhausts the atmosphere in the image forming apparatus to the outside of the apparatus is installed on the apparatus frame on the rotary unit 1 side (left side in the figure) with respect to the partition wall 5. There was a problem that the above-mentioned partition 5 interrupted air current.
[0009]
Therefore, as shown in FIG. 4, an in-machine air passage formation hole 5a is provided in the partition wall 5, and in FIG. 3, outside air from the laser irradiation light path 4c side (right side in the figure) is taken in even a little into the partition wall 5. . By doing so, the developing devices Dy, Dm, Dc, Dk and the photosensitive drum 3 can be protected from overheating due to radiant heat of the stacked sheet material 8.
[0010]
However, if the air flow path forming hole 5a is provided in the partition wall 5, the toner scattered from the developing area passes through the air flow path forming hole 5a when the toner collides with the partition wall 5 due to the rotating air current of the rotary unit 1, for example. Then, there is a possibility of entering the laser irradiation optical path 4c.
[0011]
In such a case, it is necessary for a serviceman to clean the laser scanner unit 4 that is contaminated with toner, and maintenance of the image forming apparatus becomes very difficult.
[0012]
In addition, when the air passage formation hole 5a is not provided in the partition wall 5, the toner does not enter the laser irradiation optical path 4c, but the atmosphere in the apparatus is not exhausted and the radiant heat cannot be sufficiently dissipated. For this reason, it is necessary to insert a photosensitive drum 3 using a toner that is strong against toner blocking or an expensive material with little deterioration in power, and there is a problem that time and material cost for development are extremely required.
[0013]
[Problems to be solved by the invention]
The object of the present invention is to solve the above-mentioned problems of the prior art.
[0014]
Specifically, by suppressing the temperature rise in the image forming apparatus and preventing the exposure unit from being contaminated by the toner, it is easy to maintain and maintain a high-quality image without using expensive toner or a photosensitive drum. An image forming apparatus is provided.
[0015]
[Means for Solving the Problems]
The first configuration of the image forming apparatus according to the present invention includes an image carrier that moves in a predetermined direction, an exposure unit that faces the image carrier and exposes the image carrier to form a latent image, and the exposure An irradiation light path of the exposure light beam output from the means to the image carrier, a developing means for developing the latent image of the image carrier with a developer, a partition provided between the irradiation light path and the development means, A hole provided in the partition wall for forming an air path in the apparatus; and a first exhaust path for exhausting the atmosphere in the apparatus to the outside of the apparatus by forming an exhaust path from the irradiation light path side to the developing means through the hole of the partition wall. A second blower that blows air from the irradiation light path side to the developing means side during image formation and exhausts the atmosphere inside the apparatus to the outside of the apparatus during image formation standby. and means, said first sending means the developing means side The second sending means provided in the illumination light path side, and the first blowing means and said second blowing means is provided opposite to the boundary the partitions.
[0016]
In a second configuration of the image forming apparatus according to the present invention, in the first configuration, the first blowing unit and the second blowing unit are each configured by one or a plurality of fans.
[0017]
In a third configuration of the image forming apparatus according to the present invention, in the first or second configuration, the first blowing unit and the second blowing unit are forming an air flow rate during image formation standby. Less than.
[0018]
According to a fourth configuration of the image forming apparatus of the present invention, in the first, second, or third configuration, the developing unit includes a plurality of developing units, and the plurality of developing units are rotatable developing units. Supported by a support member .
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. In addition, the same code | symbol is described to the member which is common in each figure including above-mentioned FIG. 3 and FIG. Moreover, the illustration of this embodiment does not limit this invention.
[0020]
FIG. 1 is a cross-sectional view of the image forming apparatus during image formation according to the present embodiment, and FIG. 2 is a cross-sectional view of the image forming apparatus in standby for image formation according to the present embodiment.
[0021]
The image forming apparatus shown in FIG. 1 includes a rotary unit 1 as a developing device support member, a photosensitive drum 3 as an image carrier, a laser scanner unit 4 as an exposure unit, an intermediate transfer member 6, and a transfer device 9. And a fixing device 7.
[0022]
The rotary unit 1 carries developing devices Dy, Dm, Dc, and Dk as developing means for developing each color of yellow, magenta, cyan, and black, and a rotation direction 1b (counterclockwise in the figure) around the rotation center 1a. Rotate in the rotation direction). Each developing device Dy, Dm, Dc, Dk has a developing sleeve 2, and in particular, the developing sleeve 2 a performs a developing operation on the photosensitive drum 3 in FIG. 1. At this time, the scattered toner that does not contribute to the development drifts in the air as described above.
[0023]
Further, the toner (hereinafter, scattered toner) scattered from the developing sleeve 2a does not enter the laser irradiation optical path 4c side due to, for example, the rotational air flow of the rotary unit 1 between the laser irradiation optical path 4c and the rotary unit 1. A partition wall 5 is provided.
[0024]
On the other hand, since the partition wall 5 has an in-machine air path forming hole 5a as shown in FIG. 4, there is a problem that the scattered toner enters the laser irradiation light path 4c through the in-machine air path forming hole 5a. .
[0025]
Therefore, in the image forming apparatus according to the present embodiment, the fan (first blowing unit) 11 is provided on the rotary unit 1 side (left side in the drawing) with respect to the partition wall 5, and the laser irradiation optical path 4 c (see FIG. A fan (second air blowing means) 12 is disposed on the middle right side. The fan 11 and the fan 12 can be rotated by a rotation driving means (not shown).
[0026]
Hereinafter, the operation of the fan 11 and the fan 12 will be described.
[0027]
During image formation, as shown in FIG. 1, the fan 11 rotates to exhaust the atmosphere inside the apparatus to the outside of the apparatus, and the fan 12 rotates to supply the atmosphere outside the apparatus to the inside of the apparatus. Air is blown from the laser irradiation optical path 4c side to the rotary unit 1 side. The partition wall 5 is provided with the in-machine air passage forming hole 5a, so that the airflow is not blocked.
[0028]
Thus, since the scattered toner flows in the air flow from the developing area to the rotary unit 1 side, it does not enter the laser irradiation light path 4c side from the in-machine air path forming hole 5a. As a result, since the polygon mirror 4a and the folding mirror 4b are not soiled by the toner, the output of the laser light can be maintained, and the occurrence of image defects such as thin images and missing images can be suppressed.
[0029]
Next, since toner scattering does not occur during image formation standby, as shown in FIG. 2, both the fan 11 and the fan 12 rotate so as to exhaust the atmosphere in the apparatus to the outside of the apparatus, and the ambient temperature in the apparatus Is efficiently cooled. In particular, the radiant heat of the stacked sheet material 8 is eliminated, and overheating of the developing devices Dy, Dm, Dc, Dk and the photosensitive drum 3 is suppressed.
[0030]
According to the above-described image forming apparatus according to the present embodiment, it is not necessary to put in a toner that is highly resistant to toner blocking or the photosensitive drum 3 that has little deterioration in charging performance due to heat, and it is easy to maintain and maintain a good image. be able to.
[0031]
Further, by reducing the rotational speeds of the fan 11 and the fan 12 that are waiting for image formation relative to those during image formation, noise and power consumption can be reduced. Note that the cooling efficiency in the apparatus can be maintained.
[0032]
Further, the image forming apparatus according to the present embodiment has one fan on each of the left and right, but at least one or more having the same configuration as the fan 11 on the fan 11 side so as to further improve the above-described effect. This fan may be further provided. Further, at least one or more fans having the same configuration as the fan 12 may be further provided on the fan 12 side. Furthermore, at least one or more fans having the same configuration as the fan 11 or the fan 12 may be further provided on the fan 11 side and the fan 12 side, respectively.
[0033]
In the image forming apparatus according to the present embodiment, the supply and exhaust of the fan 12 are converted by changing the rotation direction of the fan 12. However, an air supply fan and an exhaust fan are provided on the fan 12 side. The same effect can be obtained by providing at least one of each, and driving the air supply fan during image formation and driving the exhaust fan during image formation standby.
[0034]
In addition, the image forming apparatus according to the present embodiment includes a plurality of developing units for forming a color image. However, in the present invention, image forming in which toner scattered from the developing unit may enter the exposure unit side is possible. The same effect can be obtained when applied to an apparatus, for example, an image forming apparatus for monochrome images having only a black developing device.
[0035]
Further, the image forming apparatus according to the present embodiment has the fan 11 and the fan 12 on the left side and the right side of the apparatus, respectively, and blows air from the laser irradiation optical path 4c side to the rotary unit 1 side during image formation. In addition, any form may be used as long as the atmosphere in the apparatus is discharged outside the apparatus during standby for image formation.
[0036]
For example, in an image forming apparatus having an exhaust fan on the rotary unit 1 side with respect to the partition wall 5 and a ventilation hole on the laser irradiation optical path 4c side, the configuration of the present invention is simpler by always driving the fan. Is possible. Further, in the image forming apparatus having the air supply fan and the exhaust fan on the laser irradiation optical path 4c side with respect to the partition wall 5 and the ventilation holes on the rotary unit 1 side, the air supply fan during image formation. Is driven, and the exhaust fan is driven during the standby for image formation, so that the configuration of the present invention is obtained.
[0037]
【The invention's effect】
As described above, according to the present invention, air is blown from the irradiation optical path side to the developing unit side during image formation, and the atmosphere in the apparatus is exhausted outside the apparatus during standby for image formation. While suppressing temperature rise, it can prevent that a developing agent stains an exposure means. As a result, it is possible to provide an image forming apparatus that is easy to maintain and maintains a high-quality image without using expensive toner or a photosensitive drum.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an image forming apparatus during image formation according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of an image forming apparatus waiting for image formation according to an embodiment of the present invention.
FIG. 3 is a cross-sectional view of a conventional image forming apparatus.
FIG. 4 is a perspective view of a partition wall of a conventional image forming apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Rotary unit 1a ... Rotation center 1b of rotary unit 1 ... Rotation direction 2 of rotary unit 1 ... Developing sleeve 2a of developing device Dy, Dm, Dc, Dk ... Developing sleeve 3 facing photosensitive drum ... Photosensitive drum 4 ... Laser Scanner unit 4a ... polygon mirror 4b ... folding mirror 4c ... laser irradiation light path 5 ... partition wall 5a ... in-machine air path forming hole 6 ... intermediate transfer member 7 ... fixer S ... sheet material 8 ... stacked sheet material S
DESCRIPTION OF SYMBOLS 9 ... Fixing device 10 ... Developing roller 11 ... Fan 12 arrange | positioned at the rotary unit 1 side with respect to the partition 5 ... Fan Dy arrange | positioned at the laser scanner unit 4 side with respect to the partition 5 ... Yellow developing device Dc ... Cyan developing device Dm ... Magenta developer Dk ... Black developer

Claims (4)

An image carrier that moves in a predetermined direction, an exposure unit that faces the image carrier and exposes the image carrier to form a latent image, and irradiation of an exposure light beam that is output from the exposure unit to the image carrier An optical path, a developing means for developing the latent image of the image carrier with a developer, a partition provided between the irradiation optical path and the developing means, and a hole provided in the partition for forming an air path in the apparatus An image forming apparatus comprising: a first air blowing unit configured to form an exhaust path from the irradiation light path side to the developing unit side through the hole of the partition and exhaust the atmosphere in the apparatus to the outside of the apparatus;
During image formation, there is a second air blowing means for blowing air from the irradiation optical path side to the developing means side, and during image formation standby, exhausting the atmosphere in the apparatus to the outside of the apparatus, and the first air blowing means On the developing means side, the second air blowing means is provided on the irradiation light path side, and the first air blowing means and the second air blowing means are provided opposite to the partition wall. An image forming apparatus.   The image forming apparatus according to claim 1, wherein each of the first air blowing unit and the second air blowing unit includes one or a plurality of fans.   3. The image forming apparatus according to claim 1, wherein the first air blowing unit and the second air blowing unit have a smaller air flow rate during image formation standby than during image formation.   The image forming apparatus according to claim 1, wherein the developing unit includes a plurality of developing units, and the plurality of developing units are supported by a rotatable developing unit support member.

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