JP5232673B2 - Image forming apparatus and method of controlling image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a printer, a copying machine, and a facsimile, and a control method for the image forming apparatus.

  Generally, in an image forming apparatus, an electrostatic latent image formed on the surface of a photosensitive drum is developed with toner supplied from a developing device, and the developed toner image is transferred to paper by a transfer device. Then, after the toner image is fixed on the paper in the fixing device, the paper is discharged out of the apparatus.

  In such an image forming apparatus, since heat is generated from a driving unit such as a motor that rotates the roller, friction between the roller and the bearing, and a rubbing unit between the rollers, the temperature inside the apparatus tends to increase. When the temperature inside the apparatus rises, the toner in the developing device melts, the fluidity becomes poor, and a problem that a problem occurs in the toner image formed on the paper tends to occur.

  In order to solve the problem due to the temperature rise, an image forming apparatus having a configuration including a blowing fan that blows air onto a shaft portion of a roller of a developing device and an exhaust duct provided on an upper portion of the roller is disclosed ( For example, see Patent Document 1.) In Patent Document 1, the periphery of the shaft portion is cooled by a blowing fan. Furthermore, heat accumulated above the developing device is released outside the apparatus by passing air through the exhaust duct.

  In recent years, full-color copying machines as well as monochrome copying machines are often used as image forming apparatuses. As such a full-color copying machine, a tandem color copying machine is known in which a photosensitive drum is provided for each toner of magenta, cyan, yellow, and black.

  In general, since a monochrome copying is often used in a color copying machine, a monochrome image forming mode and a full color image forming mode are provided. In the monochrome image forming mode, only a black developer is operated. Therefore, in the monochrome image forming mode, the temperature rise differs between the black developing device and the other color developing devices.

  Accordingly, there has been proposed an image forming apparatus that cools the developing device by flowing air into all the developing devices in the full color image forming mode and flowing air only into the black developing device in the monochrome image forming mode. (For example, refer to Patent Document 2).

JP 2006-145727 A Japanese Patent Laid-Open No. 2003-280496

  However, the image forming apparatus disclosed in Patent Document 1 is dedicated to monochrome, and does not describe a tandem color copier. If the configuration of Patent Document 1 is also used for a tandem system, four combinations of blowing fans and exhaust ducts are required, and the structure becomes complicated.

  Further, the above-mentioned Patent Document 2 discloses only a configuration in which air is allowed to flow inside the developing device, and does not consider the heat that stays in the upper portion of the developing device.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus capable of cooling a developing device with a simple configuration and a method for controlling the image forming apparatus in consideration of the problems of the conventional image forming apparatus.

In order to achieve the above object, the first present invention provides:
A housing having a pair of opposing side surfaces;
A developing device for black and a plurality of developing devices for color, which are arranged so that their longitudinal directions are parallel to each other from one of the opposing side surface portions to each other and supply developer to each of the plurality of image carriers. A full-color developing device having
An air supply means provided on each of the opposing side surface portions, which can be switched to an intake state for intake into the apparatus or an exhaust state for exhaust to the outside of the apparatus;
Control means for performing control to switch the air supply means to the intake state or the exhaust state according to a monochrome image formation mode and a full-color image formation mode,
In the full-color developing device, the developing device for black is disposed on the one side surface side,
The controller is
In the full-color image forming mode, the air supply means on the one side surface portion and the air supply means on the other side surface portion are both controlled to be in an exhaust state,
Wherein the monochrome image forming mode, the control is such that one side portion of the air supply means is an intake state, and the air supply means of the side portion of the front SL other is controlled so as to exhaust state, is images forming device.

The second aspect of the present invention
A top plate is provided above the full-color developing device,
The intake / exhaust port of the air supply means is the image forming apparatus according to the first aspect of the present invention, wherein at least a part thereof is provided so as to face a space between the full-color developing device and the top plate.

The third aspect of the present invention
A housing having a pair of opposing side surfaces;
A developing device for black and a plurality of developing devices for color, which are arranged so that their longitudinal directions are parallel to each other from one of the opposing side surface portions to each other and supply developer to each of the plurality of image carriers. A full-color developing device having
An air supply means provided on each of the opposing side surface portions, for sucking air into the apparatus or exhausting it out of the apparatus;
In the full-color image forming mode, the air supply means on the one side surface portion and the air supply means on the other side surface portion are controlled to be in an exhaust state, and in the monochrome image forming mode, the one side surface is controlled. Control means for controlling the air supply means of the part to be in an intake state and controlling the air supply means of the other side part to be in an exhaust state .

The fourth aspect of the present invention is
A housing having a pair of opposing side surfaces;
A developing device for black and a plurality of developing devices for color, which are arranged so that their longitudinal directions are parallel to each other from one of the opposing side surface portions to each other and supply developer to each of the plurality of image carriers. A full-color developing device having
Air supply means provided on each of the opposing side surface parts, and capable of switching to a state of intake into the apparatus or a state of exhausting out of the apparatus,
In the full-color developing device, the developing device for black is a method for controlling the image forming apparatus, which is disposed on the one side surface side,
A full-color control step for controlling the air supply means on the one side surface part and the air supply means on the other side surface part to be in an exhaust state during the full-color image forming mode;
A monochrome control step for controlling the air supply means on the one side surface to be in an intake state and controlling the air supply means on the other side surface to be in an exhaust state in a monochrome image forming mode. And a method for controlling the image forming apparatus.

  According to the present invention, it is possible to provide an image forming apparatus and a control method for the image forming apparatus that can cool the developing device with a simple configuration.

1 is a front configuration diagram of a copying machine 1 according to a first embodiment of the present invention. Partial enlarged view of FIG. 1 is a perspective view of a copying machine 1 according to a first embodiment of the present invention viewed from the right side. 1 is a perspective view of a copying machine 1 according to a first embodiment of the present invention viewed from the left side. 1 is a front view of a copying machine 1 according to a first embodiment of the present invention. (A) Front view showing supply / exhaust state of cooling fans 80 and 81 when copying machine 1 according to the first embodiment of the present invention is in a full-color image forming mode, (b) copying machine according to the first embodiment of the present invention. FIG. 5 is a front view showing the supply / exhaust state of the cooling fans 80 and 81 in the monochrome image forming mode

  Hereinafter, a copying machine as an embodiment of an image forming apparatus according to the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1A is a front view of a copying machine according to an embodiment of the present invention. As shown in FIG. 1A, the copying machine 1 according to the first embodiment includes a plurality of paper feed cassettes 2 for storing sheets of paper on which images are formed at the bottom of the casing 100. In addition, the copying machine 1 includes a document reading unit 3 that reads an image of a document by using an exposure lamp, a lens, a mirror, and the like.

  The copying machine 1 according to the present embodiment is a color copying machine using a tandem system, and includes a black image forming unit 4, a yellow image forming unit 5, a cyan image forming unit 6, and a magenta image forming unit 7. Yes. Here, assuming that the right side surface portion of the casing 100 of the copying machine 1 is 110 and the left side surface portion is 120, these image forming portions are horizontally arranged from the right side surface portion 110 to the left side surface portion 120 in the order of black, yellow, cyan, and magenta. Is arranged. An intermediate transfer belt 8 for superimposing images formed by these image forming units is disposed. Further, a secondary transfer roller 9 for transferring the toner image superimposed on the intermediate transfer belt 8 onto a sheet, and a fixing unit 10 for fixing the transferred toner image on the sheet are provided.

  Further, a discharge roller pair 11 for discharging the paper that has passed through the fixing unit 10 to the outside of the copying machine 1 is provided on the side surface, and a discharge tray 12 on which the paper discharged by the discharge roller pair 11 is placed. Is provided. Note that, in FIG. 1A, the conveyance direction of the sheet is indicated by an arrow E.

  Next, the image forming unit will be described. Since the basic configurations of the four image forming units 4, 5, 6, and 7 are the same, the black image forming unit 4 will be described as an example. FIG.1 (b) is the elements on larger scale of Fig.1 (a).

  As shown in FIG. 1B, the black image forming unit 4 includes a photosensitive drum 40 made of amorphous silicon, a charger 41, a developing unit 42, a cleaning unit 43, a static eliminator 44, and the like. A laser scanner unit (hereinafter referred to as LSU) 45 that forms an electrostatic latent image by optically scanning the surface of the photosensitive drum 40 charged by the charger 41 of the black image forming unit 4 is a photosensitive drum. 40 is provided above.

  In the developing device 42 of the present embodiment, a two-component developer composed of toner and carrier is used. In order to supply toner to the photosensitive drum 40, a developing roller 46 disposed opposite to the photosensitive drum 40 and a magnetic brush are formed in the developing device 42, and only the toner of the two-component developer is supplied to the developing roller 46. A magnetic roller 47 to be supplied and a stirring member 48 for stirring the developer are provided. In addition, a panning blade 49 for regulating the thickness of the two-component developer layer on the surface of the magnetic roller 47 is provided.

  Similarly, the other image forming units 5, 6, 7 also have photosensitive drums 50, 60, 70, chargers 51, 61, 71, developing units 52, 62, 72, cleaning units 53, 63, 73, static eliminators. 54, 64, 74 and LSU 55, 65, 75, and the like.

  The developing devices 52, 62, 72 are also provided with developing rollers 56, 66, 76, magnetic rollers 47, 57, 67, 77, stirring members 58, 68, 78, and ear cutting blades 59, 69, 79. ing. These developing devices 42, 52, 62 and 72 constitute a full-color developing device 200.

  The developing units 42, 52, 62, and 72 together with the image forming units 4, 5, 6, and 7 are arranged so that their longitudinal directions are parallel to each other.

  Further, primary transfer rollers 14, 15, 16, and 17 are disposed so as to face the photosensitive drums 40, 50, 60, and 70 with the intermediate transfer belt 8 interposed therebetween. Further, on the inner side of the intermediate transfer belt 8, a counter roller 13 that faces the secondary transfer roller 9, a driving roller that drives the intermediate transfer belt 8, a driven roller, and a tension roller are disposed.

  FIG. 2 is a perspective view from the upper right of the copying machine 1 according to the first embodiment. FIG. 3 is a perspective view from the upper left of the copying machine 1. FIG. 4 is a front view of the copying machine 1 according to the first embodiment. 2, 3, and 4 show a partial configuration of the frame portion and the copying machine with the exterior removed from the casing 100. The black image forming unit 4 will be described as an example. In FIGS. 2, 3, and 4, the drum unit 400 in which the photosensitive drum 40, the charger 41, the cleaning unit 43, and the static eliminator 44 are unitized, and the developing unit 42. It is shown. The drum units 500, 600, and 700 and the developing devices 52, 62, and 72 are similarly shown in the other image forming units 5, 6, and 7.

  Although the exterior is removed in FIG. 2, the right side surface portion 110 is composed of an exterior and a frame, and as a part of the frame, stays 111, 112, 113, 114, bridged between the front and the back 115 are provided in order from the top.

  As shown in FIG. 2, in the copying machine 1 according to the first embodiment, a cooling fan 80 is placed on the upper stay 111 from the front to the back to cool the space above the developing units 42, 52, 62, and 72. Three are provided. Further, as shown in FIG. 3, the left side surface portion 120 is also composed of an exterior and a frame. As a part of the frame, stays 121, 122, 123, and 124 bridged between the front and the back are seen from above. It is provided in order. The upper stay 121 is provided with three cooling fans 81 from the front to the back. The three cooling fans 80 and the cooling fans 81 are arranged to face each other. The cooling fan 80 and the cooling fan 81 have the same configuration.

  Further, as shown in FIG. 4, a top plate 130 is provided above the developing units 42, 52, 62, 72 and the drum units 400, 500, 600, 700. Although not shown, the LSUs 45, 55, 65, and 75 of the image forming units 4, 5, 6, and 7 are provided above the top plate 130.

  The cooling is performed so that air can be supplied to or discharged from the space S between the developing units 42, 52, 62, 72 and the drum units 400, 500, 600, 700 and the top plate 130. The air intake / exhaust ports 80a and 81a of the fans 80 and 81 are disposed on the lower side of the top plate 130 so that a part thereof faces the space S.

  Further, as shown in FIGS. 2 and 4, each of the developing units 42, 52, 62, 72 is provided with two cooling ducts for cooling the inside. Further, the cooling ducts of the developing unit 42 are illustrated by 410 and 420, and the cooling ducts of the developing unit 52 are illustrated by 510 and 520. The cooling duct of the developing device 62 is illustrated by 610 and 620, and the cooling duct of the developing device 72 is illustrated by 710 and 720. Although not shown, a fan is provided for each developing device on the front side of the apparatus, and air is supplied from each fan to the two cooling ducts of each developing device, and the developing devices 42, 52, 62 are provided. , 72 is prevented from rising in temperature.

  A control unit 90 for controlling the cooling fans 80 and 81, the image forming units 4, 5, 6, 7 and the like is provided.

  An example of one side surface portion of the present invention corresponds to the right side surface portion 110 of the present embodiment, and an example of the other side surface portion of the present invention corresponds to the left side surface portion 120 of the present embodiment. An example of the air supply means of the present invention corresponds to the cooling fans 80 and 81 of the present embodiment. An example of the control means of the present invention corresponds to the control unit 90 of the present embodiment. An example of the plurality of image carriers of the present invention corresponds to the photosensitive drums 40, 50, 60, and 70 of the present embodiment. An example of a plurality of color developing devices of the present invention corresponds to the developing devices 52, 62, and 72, and an example of a black developing device of the present invention corresponds to the developing device 42.

  Next, the operation of the copier of the first embodiment will be described, and an example of the control method for the image forming apparatus of the present invention will be described at the same time.

  First, the operation in the full-color image forming mode will be described.

  When the user selects the full-color image forming mode and the document reading unit 3 starts reading the document, the control unit 90 performs control so that all of the cooling fan 80 and the cooling fan 81 are in the exhaust state. FIG. 5A is a front view of the copying machine 1, and an exhaust state is indicated by an arrow A. FIG. This control corresponds to an example of the full color control step of the present invention. Air is also fed into the cooling ducts 410, 420, 510, 520, 610, 620, 710, 720 from the fans provided on the front side of the developing units 42, 52, 62, 72.

  Based on the image data read by the document reading unit 3, the magenta image forming unit 7, the cyan image forming unit 6, the yellow image forming unit 5, and the black image forming unit 4 are uniformly charged by the charger. A latent image is formed by the LSUs 45, 55, 65, and 75 on the surfaces of the photosensitive drums 40, 50, 60, and 70, and a toner image visualized by the developing units 42, 52, 62, and 72 is formed (see FIG. 1). ).

  Next, the toner images of the respective colors formed on the photosensitive drums 40, 50, 60, and 70 are transferred onto the intermediate transfer belt 8 in the order of magenta, cyan, yellow, and black by the primary transfer rollers 14, 15, 16, and 17. Superimposed. The toner remaining on the photosensitive drums 40, 50, 60, and 70 by the primary transfer is removed by the cleaning units 43, 53, 63, and 73, and the surface of the photosensitive drums 40, 50, 60, and 70 is eliminated. , 54, 64, 74 remove the charge.

  At the same time, the paper is fed from the paper feed cassette 2, and the paper is conveyed to the secondary transfer roller 9 in accordance with the movement timing of the area (image forming area) where the toner image is formed on the intermediate transfer belt 8.

  Then, the toner image superimposed on the intermediate transfer belt 8 is transferred onto the paper by the secondary transfer roller 9 (see FIG. 2). Subsequently, the sheet on which the toner image is fixed by the fixing unit 10 is discharged onto the discharge tray 12 through the discharge roller pair 11 (see FIG. 1).

  When printing of the read image data is completed, the operations of the cooling fans 80 and 81, the photosensitive drums 40, 50, 60 and 70, the intermediate transfer belt 8 and the secondary transfer roller 9 are stopped, and the image forming operation is performed. finish.

  Next, the operation in the monochrome image forming mode will be described.

  When the user selects the monochrome image forming mode and the document reading unit 3 starts reading the document, the control unit 90 performs control so that the cooling fan 80 is in the intake state and the cooling fan 81 is in the exhaust state. FIG. 5B is a front view of the copying machine 1, where an exhaust state is indicated by an arrow A and an intake state is indicated by an arrow B. This control corresponds to an example of the monochrome control step of the present invention. Further, at the time of monochrome image formation, only the fan (not shown) for the developing device 42 among the fans for the developing devices provided on the front side of the apparatus operates, and the developing device 42 among the cooling ducts of the developing devices. Air is sent only to the cooling ducts 410 and 420.

  Then, based on the read image data, only the black image forming unit 4 is operated to form a toner image on the paper in the same manner as described above.

  As described above, in the present embodiment, in the full-color image forming mode, by setting the cooling fans 80 and 81 to the exhaust state, a strong air flow is not locally generated, and the warm air staying in the space S is uniform. The whole area can be cooled more uniformly.

  On the other hand, in the monochrome image forming mode, the developing devices 52, 62, and 72 other than the black developing device 42 are not operating, and thus the temperature is not increased. Further, in general, the black developing device 42 operates at a higher speed in the monochrome image forming mode than in the full-color image forming mode. For this reason, only the black developing device 42 becomes higher in temperature than the other developing devices 52, 62, 72, and a local temperature difference is generated. In such a case, in order to concentrate and cool the high temperature portion, the cooling effect is higher when the air is blown directly onto the object than when the warm air in the high temperature portion is sucked. Therefore, in the first embodiment, the cooling fan 80 is brought into the intake state, air is blown directly onto the black developing device 42, and the blown air is exhausted by the cooling fan 81 through the space S, thereby causing a local temperature rise. Can be suppressed.

  As described above, in the first embodiment, by simply performing different intake / exhaust control in the monochrome image formation mode and the full color image formation mode, the cooling fans 80 and 81 are simply provided on the right side surface portion 110 and the left side surface portion 120. With this configuration, it is possible to efficiently cool the warm air staying in the space above the developing units 42, 52, 62, and 72.

  In the first embodiment, the intake / exhaust ports 80a and 81a of the cooling fans 80 and 81 are partly provided so as to face the space S. Since air can be directly discharged from S, space S can be efficiently cooled.

  Next, the above embodiment will be described in more detail using examples.

Example 1
In the first embodiment, full-color image formation is continuously performed for about 3 hours in the full-color image formation mode using the copying machine 1 described above, and the toner in each developing device 42, 52, 62, 72 at that time And the temperature of the ear cutting blades 49, 59, 69, 79 were measured using a thermocouple. At this time, the outside air temperature was also measured at the same time, and the maximum value of the degree of increase from the outside air temperature was obtained. The results are shown below (Table 1). The cooling fans 80 and 81 are both controlled to be in an exhaust state as in the above embodiment.

(Example 2)
In the second embodiment, the same experiment as in the first embodiment was performed using the copying machine 1 described above, with the cooling fan 80 in the intake state and the cooling fan 81 in the exhaust state. The results are shown in the following (Table 2).

  From the first embodiment and the second embodiment, in the full-color image forming mode, the four developing units 42, It can be seen that 52, 62 and 72 can be cooled more uniformly.

  In addition, when cooling the black developing device 42, it can be seen that cooling can be effectively performed by setting the cooling fan 80 in the intake state and spraying directly on the developing device 42 as in the second embodiment.

  In this embodiment, in the monochrome image forming mode, the cooling fan 80 is in the intake state and the cooling fan 81 is in the exhaust state. However, the cooling fan 81 is controlled so as to be stopped or in the intake state. Also good. It is possible to locally cool the developing device 42 of the black image forming unit 4 by setting the cooling fan 80 to the intake state.

  In addition, the intake / exhaust ports 80a and 81a of the cooling fans 80 and 81 are provided so that a part thereof faces the space S, but the arrangement is not limited to this, and the space S faces the space S. It does not have to be. In short, it is only necessary that the space S can be sucked into or exhausted from the space S.

  Further, in the present embodiment, the cooling fan 80 is attached to the stay 111 of the right side surface portion 110, but may be attached to the exterior of the right side surface portion 110. In addition, the cooling fan 81 is also attached to the stay 121 of the left side surface portion 120, but may be attached to the exterior of the left side surface portion 120.

  In the above description, the three cooling fans 80 are configured to be able to switch between the intake state and the exhaust state. However, the configuration is not limited to such a configuration, and a plurality of cooling fans dedicated to intake or exhaust are arranged. It is good. In this case, the intake state can be achieved by operating only the cooling fan dedicated to intake, and the exhaust state can be achieved by operating only the cooling fan dedicated to exhaust.

  In the present embodiment, as shown in FIG. 1, the developing units 42, 52, 62, 72 together with the image forming units 4, 5, 6, 7 are parallel to the right side 110 and the left side 120. However, the developing units 42, 52, 62, and 72 need only be arranged from the right side surface portion 110 to the left side surface portion 120.

  In the present embodiment, as shown in FIG. 1, the developing units 42, 52, 62, and 72 together with the image forming units 4, 5, 6, and 7 are arranged horizontally, but are inclined. May be.

  In this embodiment, the description has been made using the two-component developer. However, a one-component developer may be used.

  INDUSTRIAL APPLICABILITY According to the image forming apparatus and the control method for the image forming apparatus of the present invention, it is possible to cool the developing device with a simple configuration, and it is useful as an image forming apparatus such as a printer, a copying machine, and a facsimile. It is.

DESCRIPTION OF SYMBOLS 1 Copier 2 Paper feed cassette 3 Original reading part 4 Black image forming part 5 Yellow image forming part 6 Cyan image forming part 7 Magenta image forming part 8 Intermediate transfer belt 9 Secondary transfer roller 10 Fixing part 11 Discharge roller pair 12 Discharge tray 13 Opposing rollers 80, 81 Cooling fan 100 Housing 110 Right side surface 120 Left side surface 130 Top plate

Claims (4)

A housing having a pair of opposing side surfaces;
A developing device for black and a plurality of developing devices for color, which are arranged so that their longitudinal directions are parallel to each other from one of the opposing side surface portions to each other and supply developer to each of the plurality of image carriers. A full-color developing device having
An air supply means provided on each of the opposing side surface portions, which can be switched to an intake state for intake into the apparatus or an exhaust state for exhaust to the outside of the apparatus;
Control means for performing control to switch the air supply means to the intake state or the exhaust state according to a monochrome image formation mode and a full-color image formation mode,
In the full-color developing device, the developing device for black is disposed on the one side surface side,
The controller is
In the full-color image forming mode, the air supply means on the one side surface portion and the air supply means on the other side surface portion are both controlled to be in an exhaust state,
Wherein the monochrome image forming mode, the control is such that one side portion of the air supply means is an intake state, and the air supply means of the side portion of the front SL other is controlled so as to exhaust state, images forming device. A top plate is provided above the full-color developing device,
The image forming apparatus according to claim 1, wherein at least a part of the air intake / exhaust port of the air supply unit faces the space between the full-color developing device and the top plate. A housing having a pair of opposing side surfaces;
A developing device for black and a plurality of developing devices for color, which are arranged so that their longitudinal directions are parallel to each other from one of the opposing side surface portions to each other and supply developer to each of the plurality of image carriers. A full-color developing device having
An air supply means provided on each of the opposing side surface portions, for sucking air into the apparatus or exhausting it out of the apparatus;
In the full-color image forming mode, the air supply means on the one side surface portion and the air supply means on the other side surface portion are controlled to be in an exhaust state, and in the monochrome image forming mode, the one side surface is controlled. An image forming apparatus comprising: a control unit configured to control the air supply unit in a portion to be in an intake state and to control the air supply unit in the other side portion to be in an exhaust state . A housing having a pair of opposing side surfaces;
A developing device for black and a plurality of developing devices for color, which are arranged so that their longitudinal directions are parallel to each other from one of the opposing side surface portions to each other and supply developer to each of the plurality of image carriers. A full-color developing device having
Air supply means provided on each of the opposing side surface parts, and capable of switching to a state of intake into the apparatus or a state of exhausting out of the apparatus,
In the full-color developing device, the developing device for black is a method for controlling the image forming apparatus, which is disposed on the one side surface side,
A full-color control step for controlling the air supply means on the one side surface part and the air supply means on the other side surface part to be in an exhaust state during the full-color image forming mode;
A monochrome control step for controlling the air supply means on the one side surface to be in an intake state and controlling the air supply means on the other side surface to be in an exhaust state in a monochrome image forming mode. And a method for controlling the image forming apparatus.

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