JP5656061B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile, or a complex machine thereof, and more particularly to an image forming apparatus in which a plurality of image forming units are arranged in parallel.

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine or a printer, a tandem type image forming apparatus in which a plurality of process cartridges (image forming units) are arranged in parallel so as to face an intermediate transfer belt is known (for example, (See Patent Documents 1 and 2.)
In such an image forming apparatus, in order to suppress the occurrence of an abnormal image due to a temperature rise in the image forming unit, a technique of supplying air to the image forming unit by a blower fan (intake fan) to air-cool the image forming unit. Many are used.

Specifically, in Patent Document 1, a plurality of openings are provided in a ventilation path (partition member) provided between a plurality of process cartridges (image forming units) and a writing unit (writing unit). A technique for supplying air separately to a plurality of process cartridges is disclosed.
Patent Document 2 discloses a technology in which a blower fan is installed for each of a plurality of process cartridges (image forming units), and the plurality of process cartridges are separately air-cooled by the blower fans.

A conventional image forming apparatus cannot efficiently cool a plurality of image forming units without increasing the size of the apparatus.
Specifically, since the image forming apparatus of Patent Document 1 distributes the air supplied by one blower fan to a plurality of image forming units, there is a difference in cooling efficiency depending on the positions of the image forming units arranged side by side. It might have occurred.
Moreover, since the image forming apparatus of Patent Document 2 is provided with a blower fan for each of the plurality of image forming units, the apparatus may be increased in size.

  The present invention has been made to solve the above-described problems, and provides an image forming apparatus capable of efficiently and reliably cooling a plurality of image forming units without increasing the size of the apparatus. It is in.

An image forming apparatus according to a first aspect of the present invention is an image forming apparatus in which a plurality of image forming portions for forming a toner image are arranged on an image carrier, and the air flowing from outside the apparatus is supplied to the apparatus. An air blowing fan for blowing air toward the air blowing path, and the plurality of image forming units for separately supplying the air blown by the air blowing fan in the air blowing path toward the plurality of image forming parts, respectively. and the plurality of openings formed respectively in the wall portion for partitioning between the plurality of movable members provided movably each of the plurality of the opening area of the openings in the plurality of apertures to allow variable respectively, wherein A writing unit that opposes the plurality of image forming units via an air blowing path and that irradiates light toward the image carrier in order to form a latent image on the image carrier in the plurality of image forming units; , wherein the double The openings, respectively, the light is formed so as to be irradiated on the image bearing member without blocking the light emitted from the writing unit, wherein the movable member is formed to be permeable to the light Is.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect of the present invention, the air blowing path is formed such that air is supplied to the surface of the writing unit.

According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect of the present invention, the plurality of image forming units are separated from adjacent image forming units by a wall portion. It has been done.

  According to a fourth aspect of the present invention, there is provided the image forming apparatus according to any one of the first to third aspects, further comprising temperature detecting means for detecting an ambient temperature in the apparatus, and the plurality of movable members. The members are respectively controlled so that the opening areas of the plurality of openings are increased when the ambient temperature detected by the temperature detecting means exceeds a predetermined value.

  An image forming apparatus according to a fifth aspect of the present invention is the image forming apparatus according to any one of the first to third aspects, wherein the apparatus is continuously operated or the recording medium is continuous. Detecting means for detecting the number of sheets passed through, and the plurality of movable members have an opening area in the plurality of openings when the time or the number of sheets detected by the detecting means exceeds a predetermined value. Are controlled so as to increase.

  According to a sixth aspect of the present invention, in the image forming apparatus according to any of the first to fifth aspects, the unfixed image transferred onto the recording medium is heated and pressed to perform the recording. A plurality of movable members having an opening area corresponding to an image forming unit disposed at a position close to the fixing unit among the plurality of image forming units; It is controlled so as to be larger than the opening area of the opening corresponding to the image forming unit disposed at a position far from the fixing unit.

  An image forming apparatus according to a seventh aspect of the present invention is the image forming apparatus according to any one of the first to sixth aspects, wherein the drive unit that drives the image carrier is provided by the plurality of image forming units. Provided on one end side in the width direction orthogonal to the arrangement direction, the plurality of movable members have an opening area on one end side in the width direction in which the driving unit is installed in the plurality of openings, and the driving unit is not installed It is controlled to be larger than the opening area on the other end side in the width direction.

  An image forming apparatus according to an eighth aspect of the present invention is the image forming apparatus according to any one of the first to seventh aspects, wherein an opening area of the opening is increased among the plurality of image forming units. The toner is forcibly discharged or circulated in the developing unit in the image forming unit controlled in the above manner.

  An image forming apparatus according to a ninth aspect of the present invention is the image forming apparatus according to any one of the first to eighth aspects, wherein the plurality of image forming units are a plurality of process cartridges.

  In the present application, the “process cartridge” refers to a charging unit that charges the image carrier, a developing unit (developing device) that develops a latent image formed on the image carrier, and a cleaning on the image carrier. It is defined as a unit in which at least one of the cleaning unit (cleaning device) and the image carrier are integrated and detachably installed on the image forming apparatus main body.

  The present invention provides a plurality of openings formed in each of the wall portions that partition the plurality of image forming units in order to separately supply the air blown by the blower fan in the air blowing path toward the plurality of image forming units. Since a plurality of movable members are movably provided in the plurality of openings so that the opening area of each part can be varied, the plurality of image forming units can be efficiently and reliably cooled without increasing the size of the apparatus. An image forming apparatus can be provided.

1 is an overall configuration diagram illustrating an image forming apparatus according to an embodiment of the present invention. It is a block diagram which shows an image creation part. It is a block diagram which shows an air cooling mechanism. It is a top view which shows an air cooling mechanism. It is a figure which shows operation | movement of the movable member in an air cooling mechanism. It is a flowchart which shows control of the movable member in an air cooling mechanism. It is a figure which shows another operation | movement of the movable member in an air cooling mechanism. It is a graph which shows the temperature fluctuation of the image formation part when the operation | movement of FIG. 7 is performed. It is a figure which shows another operation | movement of the movable member in an air cooling mechanism.

Embodiment.
Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, The duplication description is simplified or abbreviate | omitted suitably.

First, the configuration and operation of the entire image forming apparatus will be described with reference to FIG.
The image forming apparatus 1 according to the present embodiment is a tandem color image forming apparatus in which process cartridges 10Y, 10M, 10C, and 10BK as a plurality of image forming units are arranged in parallel so as to face the intermediate transfer belt 17. .

  In FIG. 1, 1 is an apparatus main body of a color copying machine as an image forming apparatus, 3 is a document conveying unit that conveys a document to a document reading unit 4, 4 is a document reading unit that reads image information of a document, and 6 is input image information. A writing unit (optical scanning device) that emits laser light based on the above, 7 is a paper feeding unit that stores a recording medium P such as transfer paper, and 10Y, 10M, 10C, and 10BK are colors (yellow, magenta, cyan, black) , A process cartridge as an image forming unit corresponding to, an intermediate transfer belt on which toner images of a plurality of colors are transferred in an overlapping manner, and a secondary for transferring a toner image formed on the intermediate transfer belt to a recording medium P A transfer roller, 20 is a fixing unit for fixing an unfixed image on the recording medium P, and 28 is for supplying toner of each color to the developing devices of the process cartridges 10Y, 10M, 10C, and 10BK. The toner container, 30 denotes process cartridges 10Y, 10M, 10C, cooling mechanism for cooling the 10BK and the write section 6 (air cooling device), the.

Here, a plurality of process cartridges 10Y, 10M, 10C, and 10BK as a plurality of image forming units are respectively a photosensitive drum 11 as an image carrier, a charging unit 12, a developing unit 13 (developing device), and a cleaning unit 15. (Cleaning device) is integrated (see FIG. 2). Then, each process cartridge 10Y, 10M, 10C, 10BK (image forming unit) is replaced with a new one when the life is reached.
A toner image of each color (yellow, magenta, cyan, black) is formed on the photosensitive drum 11 (image carrier) in each of the process cartridges 10Y, 10M, 10C, and 10BK.

Hereinafter, an operation during normal color image formation in the image forming apparatus will be described.
First, the document is transported from the document table by the transport rollers of the document transport unit 3 and placed on the contact glass of the document reading unit 4. Then, the document reading unit 4 optically reads the image information of the document placed on the contact glass.
Specifically, the document reading unit 4 scans an image of a document on the contact glass while irradiating light emitted from an illumination lamp. Then, the light reflected from the original is imaged on the color sensor via the mirror group and the lens. The color image information of the original is read for each color separation light of RGB (red, green, blue) by the color sensor, and then converted into an electrical image signal. Further, an image processing unit (not shown) performs color conversion processing, color correction processing, spatial frequency correction processing, and the like on the basis of RGB color separation image signals, so that yellow, magenta, cyan, and black are processed. Get color image information.

  Then, image information of each color of yellow, magenta, cyan, and black is transmitted to the writing unit 6. Laser light (exposure light) based on the image information of each color is irradiated (scanned) from the writing unit 6 onto the corresponding photosensitive drums 11 of the process cartridges 10Y, 10M, 10C, and 10BK. The

On the other hand, the four photosensitive drums 11 rotate in the clockwise direction in the figure. Referring to FIG. 2, first, the surface of the photosensitive drum 11 is uniformly charged at a position facing the charging unit 12 (charging roller) (a charging process). Thus, a charged potential is formed on the photosensitive drum 11 as an image carrier. Thereafter, the surface of the charged photosensitive drum 11 reaches the irradiation position of each laser beam.
In the writing unit 6, laser light corresponding to the image signal is emitted from the light source corresponding to each color. Although not shown, the laser light is incident on the polygon mirror and reflected, and then passes through a plurality of lenses. The laser light after passing through the plurality of lenses passes through different optical paths for each of the yellow, magenta, cyan, and black color components (this is an exposure process).

  Laser light corresponding to the yellow component is irradiated onto the surface of the photosensitive drum 11 of the first process cartridge 10Y from the left side of the drawing. At this time, the yellow component laser light is scanned in the rotational axis direction (main scanning direction) of the photosensitive drum 11 by a polygon mirror (not shown) that rotates at high speed. Thus, an electrostatic latent image corresponding to the yellow component is formed on the photosensitive drum 11 after being charged by the charging roller 12a.

  Similarly, the magenta component laser light is applied to the surface of the photosensitive drum 11 of the second process cartridge 10M from the left side of the sheet, thereby forming an electrostatic latent image of the magenta component. The laser beam corresponding to the cyan component is applied to the surface of the photosensitive drum 11 of the third process cartridge 10C from the left side of the paper, and an electrostatic latent image corresponding to the cyan component is formed. The black component laser light is applied to the surface of the photosensitive drum 11 of the process cartridge 10BK (black image forming unit), which is fourth from the left side of the drawing (the most downstream side with respect to the traveling direction of the intermediate transfer belt 17). Thus, an electrostatic latent image of the black component is formed.

Thereafter, the surface of the photosensitive drum 11 on which the electrostatic latent image of each color is formed reaches a position facing the developing unit 13 (see FIG. 2). Then, each color toner is supplied from each developing unit 13 onto the photosensitive drum 11, and the latent image on the photosensitive drum 11 is developed (this is a developing step).
Thereafter, the surface of the photosensitive drum 11 after the development process reaches a position facing the intermediate transfer belt 17 (intermediate transfer body). Here, a primary transfer roller 14 is installed at each facing position so as to contact the inner peripheral surface of the intermediate transfer belt 17. Then, at the position of the primary transfer roller 14, the toner images of the respective colors formed on the photosensitive drum 11 are sequentially transferred onto the intermediate transfer belt 17 (first transfer process).

Then, the surface of the photosensitive drum 11 after the first transfer step reaches a position facing the cleaning unit 15 (see FIG. 2). The untransferred toner remaining on the photosensitive drum 11 (image carrier) is collected by the cleaning unit 15 (cleaning process).
Thereafter, the surface of the photoconductive drum 11 passes through the position of a static elimination unit (not shown), and a series of image forming processes on the photoconductive drum 11 is completed.

On the other hand, the surface of the intermediate transfer belt 17 on which the images of the respective colors on the photosensitive drum 11 are transferred in an overlapping manner travels in the direction of the arrow in the drawing and reaches the position of the secondary transfer roller 18. Then, the full color image on the intermediate transfer belt 17 is secondarily transferred onto the recording medium P at the position of the secondary transfer roller 18 (second transfer step).
Thereafter, the surface of the intermediate transfer belt 17 reaches the position of the intermediate transfer belt cleaning unit 9 (cleaning unit). Then, the untransferred toner on the intermediate transfer belt 17 is collected by the intermediate transfer belt cleaning unit 9, and a series of transfer processes on the intermediate transfer belt 17 is completed.

Here, the recording medium P at the position of the secondary transfer roller 18 is conveyed from the paper supply unit 7 via the conveyance guide, the registration roller 19 and the like.
Specifically, the transfer paper P fed by the paper feed roller 8 from the paper feed unit 7 that stores the recording medium P is guided to the registration roller 19 after passing through the conveyance guide. The recording medium P that has reached the registration roller 19 is conveyed toward the position of the secondary transfer roller 18 in synchronization with the toner image on the intermediate transfer belt 17.

Thereafter, the recording medium P on which the full-color image is transferred is guided to the fixing unit 20. In the fixing unit 20, the color image is fixed on the recording medium P at the nip between the fixing roller (heating roller) and the pressure roller. That is, the unfixed image transferred onto the recording medium P in the second transfer step is heated and pressurized by the fixing unit 20 so that the image is fixed on the recording medium P.
The recording medium P after the fixing step is discharged as an output image outside the apparatus main body 1 by the paper discharge roller 29 and then stacked on the paper discharge unit 5 to complete a series of image forming processes.
As shown in FIG. 1, the image forming apparatus 1 according to the present exemplary embodiment includes a blower fan 31 that blows air that flows in from the outside of the image forming apparatus 1 toward a blower path 32 inside the image forming apparatus 1. The air-cooling mechanism 30 having the above is installed, which will be described in detail later.

Next, the image forming unit of the image forming apparatus will be described in detail with reference to FIG.
FIG. 2 is a configuration diagram illustrating the black process cartridge 10BK (image forming unit). The other three process cartridges 10Y, 10M, and 10C (image forming units) are configured substantially the same as the black process cartridge 10BK, except that the color of the toner used in the image forming process is different. The illustration and description thereof are omitted.

  As shown in FIG. 2, the process cartridge 10BK contains a photosensitive drum 11 as an image carrier, a charging unit 12 for charging the photosensitive drum 11, and an electrostatic latent image formed on the photosensitive drum 11. A developing unit 13 for developing and a cleaning unit 15 for collecting untransferred toner on the photosensitive drum 11 are integrally stored in a case.

Here, the photosensitive drum 11 as an image bearing member is a negatively charged organic photosensitive member, and a photosensitive layer or the like is provided on a drum-shaped conductive support. Although not shown, the photosensitive drum 11 has an undercoat layer that is an insulating layer, a charge generation layer and a charge transport layer as a photosensitive layer, and a protective layer (surface layer) in this order on a conductive support as a base layer. Are stacked.
The charging unit 12 is a charging roller formed by covering an outer periphery of a conductive metal core with an intermediate resistance elastic layer. Then, a predetermined voltage is applied to the charging unit 12 (charging roller) from a power supply unit (not shown), thereby uniformly charging the surface of the opposing photoconductive drum 11.

  The developing unit 13 (developing device) mainly includes a developing roller 13a facing the photoconductive drum 11, a first transporting screw 13b1 facing the developing roller 13a, and a first transporting screw 13b1 facing the first transporting screw 13b1 via a partition member. It is comprised by the 2 conveyance screw 13b2 and the doctor blade 13c facing the developing roller 13a. The developing roller 13a includes a magnet that is fixed inside and forms a magnetic pole on the peripheral surface of the roller, and a sleeve that rotates around the magnet. A plurality of magnetic poles are formed on the developing roller 13a (sleeve) by the magnet, and the developer is carried on the developing roller 13a. In the developing unit 13, a two-component developer composed of a carrier and a toner is accommodated.

  Referring to FIG. 2, a cleaning unit 15 (cleaning device) includes a cleaning blade 15a in contact with the photosensitive drum 11, and a waste toner collection container (not shown) using untransferred toner collected in the cleaning unit 15 as waste toner. The transfer coil 15b (the transfer tube 16) and the like that are transferred toward the camera are installed. The cleaning blade 15a is made of a rubber material such as urethane rubber, and is in contact with the surface of the photosensitive drum 11 at a predetermined angle and a predetermined pressure. As a result, deposits such as untransferred toner adhering to the photosensitive drum 11 are mechanically scraped and collected in the cleaning unit 15. The untransferred toner collected in the cleaning unit 15 is transported to a waste toner collecting container (not shown) via a transport pipe 16 (a transport coil 15b is provided) and is discarded as waste toner. The toner is collected inside the toner collecting container.

The image forming process described above will be described in more detail with reference to FIG.
The developing roller 13a rotates in the arrow direction (counterclockwise direction) in FIG. The developer in the developing unit 13 is replenished from the toner container 28 by a toner replenishing unit (not shown) by the rotation of the first transport screw 13b1 and the second transport screw 13b2 that are disposed so as to interpose a partition member therebetween. The toner circulates in the longitudinal direction while being agitated and mixed with the toner (the direction perpendicular to the paper surface of FIG. 2).

  The toner that is frictionally charged and adsorbed on the carrier is carried on the developing roller 13a together with the carrier. The developer carried on the developing roller 13a then reaches the position of the doctor blade 13c. The developer on the developing roller 13a is adjusted to an appropriate amount at the position of the doctor blade 13c and then reaches a position facing the photosensitive drum 11 (development region).

  Thereafter, in the developing region, the toner in the developer adheres to the electrostatic latent image formed on the surface of the photosensitive drum 11. Specifically, the latent image potential (exposure potential) of the image portion irradiated with the laser beam L and the electric field formed by the potential difference (development potential) between the development bias applied to the developing roller 13a cause the toner to become a latent image. (Toner image is formed).

  Thereafter, most of the toner adhering to the photosensitive drum 11 in the developing process is transferred onto the intermediate transfer belt 17. Then, the untransferred toner remaining on the photosensitive drum 11 is collected in the cleaning unit 15 by the cleaning blade 15a.

  Here, although not shown in the figure, the toner replenishing portion provided in the apparatus main body 1 includes a bottle-shaped toner container 28 configured to be replaceable, and holds and rotates the toner container 28, and the developing unit 13 is newly installed. And a toner hopper for replenishing toner. Also, a new toner (any one of yellow, magenta, cyan, and black) is accommodated in the toner container 28. In addition, a spiral protrusion is formed on the inner peripheral surface of the toner container 28 (toner bottle).

  The new toner in the toner container 28 is appropriately supplied from the toner supply port into the developing unit 13 as the toner in the developing unit 13 (existing toner) is consumed. Although illustration is omitted, the consumption of toner in the developing unit 13 is indirectly caused by a reflection type photosensor facing the photosensitive drum 11 and a magnetic sensor installed below the second conveying screw 23b2 of the developing unit 13. Or detected directly.

Hereinafter, the configuration and operation of the air cooling mechanism 30 (air cooling device), which is characteristic in the present embodiment, will be described in detail.
FIG. 3 is a configuration diagram showing the air cooling mechanism 30 and is a view of the air cooling mechanism 30 as seen from the front, similarly to FIG. FIG. 4 is a top view showing the air cooling mechanism 30. FIG. 5 is a diagram showing the operation of the movable plates 34Y, 34M, 34C, 34BK (movable members) in the air cooling mechanism 30 shown in FIG.
3 to 5, the air cooling mechanism 30 includes a blower fan 31, a duct 33, a partition member 32 as a blower path, movable plates 34Y, 34M, 34C, 34BK as movable members, and the like. .

The blower fan 31 blows air flowing from outside the apparatus toward the partition member 32 (air supply path) through the duct 33 in the apparatus. In the present embodiment, as shown in FIG. 4, the blower fans 31 are arranged on the far side in the width direction (upward in FIG. 4) and on the near side in the width direction (downward in FIG. 4), respectively. However, the installation position and the number of the blower fans 31 are not limited to this.
The partition member 32 (case) functions as a blowing path through which the air blown by the blower fan 31 flows, and also functions as a housing unit that houses the process cartridges 10Y, 10M, 10C, and 10BK as the four image forming units. doing. In the present embodiment, the functions of the air blowing path and the housing part in the partition member 32 can be separated from each other (the air blowing path and the housing part can be configured as separate members).

  Here, in the present embodiment, the air blown by the blower fan 31 in the blower path (partition member 32) is separately supplied toward the four process cartridges 10Y, 10M, 10C, and 10BK (imaging units). Therefore, four openings 32aY, 32aM, 32aC, and 32aBK are formed in the wall portions that partition the four process cartridges 10Y, 10M, 10C, and 10BK, respectively. That is, in the partition member 32, openings 32aY, 32aM, 32aC, and 32aBK (inlet ports) for allowing the air supplied by the blower fan 31 to flow below the process cartridges 10Y, 10M, 10C, and 10BK, respectively. Is formed. That is, air flows in the partition member 32 (ventilation path) as indicated by white arrows in FIG. As a result, the process cartridges 10Y, 10M, 10C, and 10BK can be air-cooled, and the occurrence of abnormal images (white streaks, poorly developed images, etc.) due to the temperature rise of the image forming unit can be suppressed. .

Further, in the present embodiment, the four opening portions 32aY, 32aM, 32aC, and 32aBK each have four movable members so that the opening areas of the four opening portions 32aY, 32aM, 32aC, and 32aBK can be varied. Movable plates 34Y, 34M, 34C, and 34BK are movably provided.
Specifically, as shown in FIG. 3, the four movable plates 34Y, 34M, 34C, and 34BK (movable members) are respectively in the direction of the double arrow in FIG. 3 with respect to the four openings 32aY, 32aM, 32aC, and 32aBK. The sliding amount can be varied by changing the movement amount. Although not shown, the four movable plates 34Y, 34M, 34C, and 34BK (movable members) are each connected to a drive unit 50 including a rack and pinion mechanism, and their movement positions are detected by a position sensor. The opening areas of the four openings 32aY, 32aM, 32aC, and 32aBK are each variable.

With such a configuration, the amount of air sent toward the four process cartridges 10Y, 10M, 10C, and 10BK (image forming units) can be varied separately, so that the four process cartridges 10Y, 10M, 10C, and 10BK are variable. It is possible to efficiently and reliably cool the (image forming unit).
In the present embodiment, since the blower fan 31 and the blower path are not provided for each of the process cartridges 10Y, 10M, 10C, and 10BK, the image forming apparatus 1 can be prevented from being enlarged.

Here, in the present embodiment, as shown in FIG. 3, the four openings 32aY, 32aM, 32aC, and 32aBK are emitted from the laser beam emitted from the writing unit 6 (the optical path indicated by the broken line arrow in FIG. 3). The photosensitive drums 11 are irradiated with laser light without blocking. That is, the openings 32aY, 32aM, 32aC, and 32aBK are the partition members 32 (accommodating) that accommodate the process cartridges 10Y, 10M, 10C, and 10BK (imaging units) in order to allow the laser light emitted from the writing unit 6 to pass therethrough. Part). Such a slit is originally a necessary configuration, and this slit is also used as an air inlet to each of the process cartridges 10Y, 10M, 10C, and 10BK (image forming unit). The configuration will be simplified.
The four movable plates 34Y, 34M, 34C, and 34BK (movable members) are each formed so as to transmit laser light. Specifically, in the present embodiment, a thin glass plate or a thin transparent resin plate is used as the movable plates 34Y, 34M, 34C, and 34BK (movable members). In this way, by using the movable plates 34Y, 34M, 34C, and 34BK having light transmittance, the movable plates 34Y, 34M, 34C, and 34BK (movable members) cover the openings 32aY, 32aM, 32aC, and 32aBK. Even when it is in the position, there is no problem that the exposure process in which the laser light emitted from the writing unit 6 is irradiated to each photosensitive drum 11 is hindered.
In FIG. 3, the movable plates 34Y, 34M, 34C, and 34BK are shown thicker for easy visual recognition. However, the movable plates 34Y, 34M, 34C, and 34BK are actually airflows in the ventilation path. It is formed so thin that it does not change the optical path of the laser beam.

  Moreover, as shown in FIG.1 and FIG.3, in this Embodiment, the partition member 32 as a ventilation path is formed so that air may be supplied to the surface (ceiling surface) of the writing part 6. As shown in FIG. That is, referring to FIG. 3, the air flowing into the partition member 32 by the blower fan 31 is supplied to the surface (ceiling surface) of the writing unit 6, so that the temperature rises easily due to heat generated by the polygon mirror or the like. The temperature rise of the writing unit 6 itself is also reduced.

As shown in FIG. 4, in the present embodiment, the four process cartridges 10Y, 10M, 10C, and 10BK (image forming units) are separated from adjacent process cartridges by a wall 32d.
Specifically, as shown in FIG. 4, the partition member 32 is bridged between a front plate 32b installed on the front side in the width direction and a rear plate 32c installed on the back side in the width direction. Two wall portions 32d are provided. The front plate 32b, the rear plate 32c, and the five wall portions 32d divide a storage portion that stores the four process cartridges 10Y, 10M, 10C, and 10BK (image forming portion) into four spaces. .
With such a configuration, the amount of air sent to the four process cartridges 10Y, 10M, 10C, and 10BK (image forming units) by the operation of the four movable plates 34Y, 34M, 34C, and 34BK (movable members) is separately set. When it is changed, it is possible to prevent air from entering and leaving the space of the adjacent process cartridge, so that the four process cartridges 10Y, 10M, 10C, and 10BK (imaging portions) can be efficiently air-cooled as intended. It becomes easy.

  Referring to FIG. 4, the four insertion ports 32bY, 32bM, 32bC, and 32bBK formed in the front side plate 32b are for attaching and detaching the four process cartridges 10Y, 10M, 10C, and 10BK to the apparatus main body 1. Is the opening. Specifically, when the front cover (not shown) of the apparatus main body 1 is opened, the four insertion ports 32bY, 32bM, 32bC, and 32bBK are exposed on the front side in the width direction, and the user can use the process cartridge in this state. 10Y, 10M, 10C, and 10BK are attached and detached.

  Here, in the present embodiment, as shown in FIG. 3, the image forming apparatus 1 is provided with a temperature sensor 60 as temperature detecting means for detecting the ambient temperature in the apparatus. Then, the four movable plates 34Y, 34M, 34C, 34BK (movable members) have four openings 32aY, 32aM, when the ambient temperature detected by the temperature sensor 60 (temperature detection means) exceeds a predetermined value. Control is performed so that the opening areas in 32aC and 32aBK are increased. That is, the four movable plates 34Y, 34M, 34C, and 34BK (movable members) are normally in the home positions shown in FIG. 4 and the openings 32aY and 32aM when the ambient temperature in the apparatus exceeds a predetermined value. , 32aC and 32aBK are slid in the direction of the black arrow shown in FIG. Thereby, the temperature rise of process cartridge 10Y, 10M, 10C, 10BK can be efficiently reduced according to the fluctuation | variation of the atmospheric temperature in an apparatus.

FIG. 6 is a flowchart showing in more detail the control of the movable plates 34Y, 34M, 34C, and 34BK.
As shown in FIG. 6, first, the temperature in the apparatus is detected by the temperature sensor 60, and it is determined whether the detected temperature t is larger than a first predetermined value M1 (steps S1 and S2). As a result, if the control unit 80 determines that the detected temperature t is lower than the first predetermined value M1, the process cartridges 10Y, 10M, 10C, and 10BK have not increased in temperature (or are smaller). As a thing, the drive part 50 is controlled so that the position of movable plate 34Y, 34M, 34C, 34BK may be returned to the home position shown in FIG. 4 (step S6), and this flow is complete | finished (step S8).
On the other hand, when the control unit 80 determines that the detected temperature t is higher than the first predetermined value M1 in step S2, the temperature of the process cartridges 10Y, 10M, 10C, and 10BK is increased. Next, it is determined whether the apparatus is in a print job (step S3). As a result, if it is determined that the print job is not in progress, the movable plates 34Y, 34M, 34C, 34BK are assumed to have to be quickly reduced in temperature rise of the process cartridges 10Y, 10M, 10C, 10BK. The drive unit 50 is controlled so as to be moved to the open position shown in FIG. 5 (step S7), and this flow is ended (step S8).
On the other hand, if it is determined in step S3 that the print job is in progress, the temperature t detected by the temperature sensor 60 is set to the second predetermined value M2 ( > M1) (step S4). If it is determined that the detected temperature t is lower than the second predetermined value M2, the print job is continued (step S5). The flow after step S4 is continued. On the other hand, if it is determined in step S4 that the detected temperature t is higher than the second predetermined value M2 by the control unit 80, the temperature rise of the process cartridges 10Y, 10M, 10C, 10BK is large. Assuming that the temperature rise needs to be quickly reduced, the drive unit 50 is controlled to move the movable plates 34Y, 34M, 34C, and 34BK to the open positions shown in FIG. 5 (step S7), and this flow Is finished (step S8).

In the present embodiment, the movable plates 34Y, 34M, 34C, and the like are optimized so that the opening areas of the openings 32aY, 32aM, 32aC, and 32aBK are optimized based on the temperature in the apparatus detected by the temperature sensor 60. The position of 34BK was adjusted and controlled.
On the other hand, as shown in FIG. 3, a counter 70 (or a time during which the apparatus is continuously operated) serving as a detecting means for detecting the number of recording media P that are continuously passed through the apparatus. Detection means) for detecting the four movable plates 34Y, 34M, 34C, 34BK (movable members), and the number of continuous sheets (or continuous operation time) detected by the counter 70 (detection means) is a predetermined value. Can be controlled such that the opening areas in the four openings 32aY, 32aM, 32aC, and 32aBK are increased. That is, when the four movable plates 34Y, 34M, 34C, and 34BK (movable members) are normally at the home position shown in FIG. 4 and the continuous sheet passing number (or continuous operation time) exceeds a predetermined value. Slides in the direction of the black arrow shown in FIG. 5 so that the opening areas in the openings 32aY, 32aM, 32aC, and 32aBK become large. Thereby, the temperature rise of the process cartridges 10Y, 10M, 10C, and 10BK can be efficiently reduced according to the number of continuous sheets (or continuous operation time) that correlates with the change in the atmospheric temperature in the apparatus. .

Referring to FIG. 7, in the present embodiment, four movable plates 34Y, 34M, 34C, 34BK are arranged at positions close to fixing unit 20 among four process cartridges 10Y, 10M, 10C, 10BK. The opening areas of the openings 32aBK and 32aC corresponding to the processed cartridges 10BK and 10C are larger than the opening areas of the openings 32aY and 32aM corresponding to the process cartridges 10Y and 10M disposed at positions far from the fixing unit 20. It can also be controlled.
Specifically, as shown in FIG. 1, among the four process cartridges 10Y, 10M, 10C, and 10BK, the black process cartridge 10BK and the cyan process cartridge that are disposed relatively close to the fixing unit 20 10C is due to the influence of the heat of the fixing unit 20 that reaches a high temperature by heating the heater as compared with the yellow process cartridge 10Y and the magenta process cartridge 10M that are disposed relatively far from the fixing unit 20. Temperature rises easily. Such a phenomenon can be understood from the graph shown in FIG. 8 (the graph showing the relationship between the continuous transient time and the temperature rise value).
In contrast, when the continuous operation time reaches a predetermined value (or when the temperature detected by the temperature sensor 60 installed at the position of the black process cartridge 10BK or the cyan process cartridge 10C reaches a predetermined value. In addition, the positions of the movable plates 34BK and 34C are adjusted and controlled so that the opening areas of the openings 32aBK and 32aC corresponding to the black and cyan process cartridges 10BK and 10C become large (fully open), and yellow The positions of the movable plates 34Y and 34M are adjusted and controlled so that the opening areas of the openings 32aY and 32aM corresponding to the process cartridges 10Y and 10M for magenta and magenta are reduced (closed) (state shown in FIG. 7). .) As a result, the black and cyan process cartridges 10BK and 10C disposed relatively close to the fixing unit 20 can be used for yellow and cyan by adjusting and controlling the four movable plates 34Y, 34M, 34C, and 34BK. Since extra air is supplied to the magenta process cartridges 10Y and 10M, as shown by the broken line curve, as shown in FIG. The temperature will drop. On the other hand, the process cartridges 10Y and 10M for yellow and magenta are not supplied with air as shown in FIG. 8 by the adjustment control of the four movable plates 34Y, 34M, 34C and 34BK. Although the temperature rises, as indicated by the dashed curve, the temperature rise is low compared to the black and cyan process cartridges 10BK and 10C, so there is no problem due to the temperature rise.

Further, when the above-described control is performed, toner is forcibly discharged or discharged at the developing unit 13 in the black and cyan process cartridges 10BK and 10C, which are controlled so that the opening areas of the openings 32aBK and 32aC are increased. It can be controlled to circulate.
More specifically, the developing unit 13 in the black and cyan process cartridges 10BK and 10C, which are likely to increase in temperature, develops from the toner container 28 at a timing and level that does not affect the image quality of the toner image formed on the photosensitive drum 11. While supplying toner to the unit 13, a background stain image is formed on the photosensitive drum 11 and the toner is forcibly discharged from the developing unit 13, or the toner is circulated in a circulation path in the developing unit 13. As a result, heat circulation of the developing unit 13 is promoted together with the flow of toner in the developing unit 13, so that it is easy to reduce the temperature increase in the black and cyan process cartridges 10BK and 10C that are likely to increase in temperature.

Referring to FIG. 9, in the present embodiment, a plurality of movable plates 34Y1, 34Y2, 34M1, 34M2, 34C1, 34C2, 34BK1, and 34BK2 are driven at a plurality of openings 32aY, 32aM, 32aC, and 32aBK. (An opening area on one end side in the width direction where the driving unit (drive motor) that drives each photosensitive drum 11 is installed) is larger than an opening area on the other end side in the width direction where the driving unit is not installed. It can also be controlled to be larger.
Specifically, referring to FIG. 9, a drive motor as a drive unit for driving the four process cartridges 10Y, 10M, 10C, and 10BK (photosensitive drum 11) includes a rear plate 32c (four process cartridges 10Y, 10M, 10C and 10BK on one end side in the width direction orthogonal to the arrangement direction. For this reason, the four process cartridges 10Y, 10M, 10C, and 10BK are all affected by the heat of the drive unit, and the back side in the width direction is likely to rise in temperature compared to the front side in the width direction.
On the other hand, as shown in FIG. 9, the movable plates that change the opening area of each opening 32aY, 32aM, 32aC, and 32aBK are movable plates 34Y1, 34M1, 34C1, and 34BK1 on the back side in the width direction. The movable plate 34 </ b> Y <b> 2, 34 </ b> M <b> 2, 34 </ b> C <b> 2, 34 </ b> BK <b> 2 on the front side in the width direction is divided so that they can be independently slid. When the continuous operation time reaches a predetermined value (or when the temperature detected by the temperature sensor 60 installed on the back side in the width direction reaches a predetermined value), the movable plates 34Y1, 34M1, By opening 34C1 and 34BK1 and closing the movable plates 34Y2, 34M2, 34C2, and 34BK2 on the front side in the width direction, the four process cartridges 10Y, 10M, 10C, and 10BK are likely to have a temperature rise on the back side in the width direction. The temperature can be reduced efficiently.

  Although not shown in the drawings, in the present embodiment, only the black movable plate 34BK is opened in the monochrome mode (a mode in which only the black process cartridge 10BK is used to form a monochrome image). Thus, the other movable plates 34Y, 34M, and 34C can be controlled to be closed. Even in such a case, the temperature rise of the black process cartridge 10BK that easily causes a temperature rise and thereby easily affects the image can be efficiently reduced.

  Although not shown, in the present embodiment, the opening areas of the openings 32aY, 32aM, 32aC, and 32aBK are narrowed in the order closer to the blower fan 31 (the opening area that is farther from the blower fan 31 is larger). Can also be controlled). Specifically, the movable plates 34Y, the opening area of the yellow opening 32aY <the opening area of the magenta opening 32aM <the opening area of the cyan opening 32aC <the black opening 32aBK are established. 34M, 34C, 34BK are controlled. As a result, the amount of air supplied to the four process cartridges 10Y, 10M, 10C, and 10BK can be made uniform regardless of the distance from the blower fan 31.

  As described above, according to the present embodiment, the air blown by the blower fan 31 in the partition member 32 (blowing path) is directed toward the plurality of process cartridges 10Y, 10M, 10C, 10BK (imaging units). The opening areas of the plurality of openings 32aY, 32aM, 32aC, and 32aBK respectively formed in the wall portions that partition between the plurality of process cartridges 10Y, 10M, 10C, and 10BK to be supplied separately can be varied. Since a plurality of movable plates 34Y, 34M, 34C, 34BK (movable members) are movably provided in the plurality of openings 32aY, 32aM, 32aC, 32aBK, respectively, a plurality of processes can be performed without increasing the size of the image forming apparatus 1. Cool cartridges 10Y, 10M, 10C, 10BK efficiently and reliably Can.

In the present embodiment, the process cartridges 10Y, 10M, 10C, and 10BK are configured by integrating the units in the image forming unit (the photosensitive drum 11, the charging unit 12, the developing unit 13, and the cleaning unit 15). Thus, the image forming unit is made compact and the maintenance workability is improved. On the other hand, a part or all of the image forming unit (photosensitive drum 11, charging unit 12, developing unit 13, cleaning unit 15) can be replaced with the apparatus main body 1 as a single unit without being a component of the process cartridge. It can also be configured to be installed. In such a case, the same effect as that of the present embodiment can be obtained.
In the present embodiment, the present invention is applied to the image forming apparatus equipped with the two-component developing type developing unit 13 using the two-component developer. However, the one-component developing type using the one-component developer is used. Of course, the present invention can also be applied to an image forming apparatus in which the developing unit 13 is mounted.

In the present embodiment, the present invention is applied to an image forming apparatus in which four image forming units 10Y, 10M, 10C, and 10BK are arranged side by side. However, the number of image forming units is two, three, or Naturally, the present invention can also be applied to five or more image forming apparatuses arranged in parallel.
Further, in the present embodiment, the present invention is applied to an image forming apparatus in which a plurality of image forming units 10Y, 10M, 10C, and 10BK are arranged in parallel so as to face the intermediate transfer belt 17. Naturally, the present invention can also be applied to an image forming apparatus in which an image portion is arranged in parallel so as to face other members (for example, a transfer conveyance belt in a direct transfer system).
In these cases, the same effects as in the present embodiment can be obtained.

  It should be noted that the present invention is not limited to the present embodiment, and it is obvious that the present embodiment can be modified as appropriate within the scope of the technical idea of the present invention, other than suggested in the present embodiment. is there. In addition, the number, position, shape, and the like of the constituent members are not limited to the present embodiment, and the number, position, shape, and the like suitable for implementing the present invention can be achieved.

1 image forming apparatus body (apparatus body),
6 Writing section,
10Y, 10M, 10C, 10BK process cartridge (imaging part),
11 Photosensitive drum (image carrier),
17 Intermediate transfer belt,
20 fixing section,
30 Air cooling mechanism,
31 Blower fan,
32 partition member (air blowing path),
32aY, 32aM, 32aC, 32aBK opening,
33 Duct,
34Y, 34M, 34C, 34BK Movable plates (movable members).

JP 2009-9074 A JP 2007-219398 A

Claims (9)

An image forming apparatus in which a plurality of image forming units that form toner images on an image carrier are arranged in parallel,
A blower fan that blows air flowing from outside the apparatus toward a blower path in the apparatus;
A plurality of openings respectively formed in wall portions for partitioning between the plurality of image forming units in order to separately supply the air blown by the blower fan in the blowing path toward the plurality of image forming units. And
A plurality of movable members movably provided in the plurality of openings so that the opening areas of the plurality of openings can be varied;
A writing unit that opposes the plurality of image forming units via the air blowing path and irradiates the image carrier with light to form a latent image on the image carrier in the plurality of image forming units. When,
Equipped with a,
Each of the plurality of openings is formed such that the light is emitted to the image carrier without blocking light emitted from the writing unit.
The image forming apparatus , wherein the movable member is formed to transmit the light . The image forming apparatus according to claim 1, wherein the air blowing path is formed such that air is supplied to a surface of the writing unit. The image forming apparatus according to claim 1, wherein the plurality of image forming units are separated from adjacent image forming units by a wall portion. Provided with temperature detection means for detecting the ambient temperature in the device,
The plurality of movable members are respectively controlled such that an opening area in the plurality of openings is increased when an ambient temperature detected by the temperature detection unit exceeds a predetermined value. The image forming apparatus according to claim 1. A detection means for detecting the time during which the apparatus is continuously operated or the number of sheets in which the recording medium is continuously fed;
The plurality of movable members are respectively controlled such that an opening area in the plurality of openings is increased when the time or the number of sheets detected by the detection unit exceeds a predetermined value. The image forming apparatus according to claim 1. A fixing unit that heats and pressurizes an unfixed image transferred onto a recording medium and fixes the image on the recording medium;
The plurality of movable members are disposed at a position where an opening area of the opening corresponding to the image forming unit disposed at a position near the fixing unit among the plurality of image forming units is far from the fixing unit. The image forming apparatus according to claim 1, wherein the image forming apparatus is controlled to be larger than an opening area of the opening corresponding to the image forming unit. A drive unit for driving the image carrier is provided on one end side in the width direction orthogonal to the arrangement direction of the plurality of image forming units,
In the plurality of movable members, an opening area on one end side in the width direction where the driving unit is installed in the plurality of openings is larger than an opening area on the other end side in the width direction where the driving unit is not installed. The image forming apparatus according to claim 1, wherein the image forming apparatus is controlled as described above.   The toner is forcibly discharged or circulated in a developing unit of the image forming unit that is controlled to increase an opening area of the opening among the plurality of image forming units. The image forming apparatus according to claim 1.   The image forming apparatus according to claim 1, wherein the plurality of image forming units are a plurality of process cartridges.

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