JP5125865B2 - Image forming apparatus and developing apparatus - Google Patents

Description

  The present invention relates to an electrophotographic image forming apparatus and a developing device used in the image forming apparatus.

  In a developing device that uses a two-component developer containing toner and a magnetic carrier, the consumed toner is replenished and the toner concentration in the developer is kept constant.

  Further, when the developer deteriorates due to long-term operation, the developer is replaced by taking out the deteriorated developer from the developing device and loading a new developer.

  Since the developer containing the magnetic carrier is magnetically attracted to the developing roller, it is difficult to take out the developer from the developing device. Skilled technology is required for replacing the developer, and it takes a long time to replace the developer. is there.

Japanese Patent Application Laid-Open No. 2004-133620 proposes that the developer can be easily taken out by rotating the magnet in the developing roller to weaken the magnetic field in the developer taking-out portion.
No. 5-98355

  A problem to be solved by the present invention will be described with reference to FIG.

  FIG. 1A shows the developing device 4 in an activated state, and FIG. 1B shows the developing device 4 when the developer is replaced.

  An outer shape of the developing device 4 is formed by the housing 41 and the cover 42, and a developing roller 50, screws 51 and 52 as stirring / conveying means, a developer regulating member 53, a developer guide member 54, and the like are disposed therein. . The inside of the developing device is divided into a developing chamber 40A and a stirring / conveying chamber 40B by a partition member 43.

  The developing roller 50 includes a magnet roll having a plurality of magnetic poles and a developing sleeve that rotates as indicated by an arrow.

  The magnet roll has two north poles N1, N2 and three south poles S1, S2, S3.

  The N1 pole constitutes a developing pole, and S1 and S2 adjacent to the same pole constitute a peeling pole that forms a repulsive magnetic field and separates the developer D from the developing roll 51.

  In FIG. 1A, the toner is supplied to the agitating / conveying chamber 40B, and is mixed in the developer D composed of the toner and the carrier by the rotation of the screw 51.

  The developer D mixed with the replenishing toner is supplied to the developing chamber 40A through a passage (not shown).

  By the rotation indicated by the arrow of the developing roller 50, the developer D is drawn up from the developing chamber and is regulated by the developer regulating member 53, so that a layer of the developer D is formed on the developing roller 50.

  The developer D layer develops an electrostatic latent image on a photoreceptor (not shown) arranged on the right side of the developing device 4 to form a toner image.

  The developed developer D passes under the screw 52 and returns to the stirring / conveying chamber 40B.

  The developer D that has been consumed by development and has a reduced toner concentration is replenished with toner in the stirring / conveying chamber 40B.

  Continuous development is performed by the circulation of the developer D described above, and continuous image formation is performed.

  When the developer D deteriorates due to a long-term image forming operation, the old developer D is removed from the developing device 4 and the developer is replaced with a new developer D.

  This developer replacement is performed by the user or service person taking out the developing device 4 from the image forming apparatus main body GH.

  At the time of changing the developer, the developing device 4 is turned sideways as shown in FIG. 1B, that is, the housing 41 occupying the bottom in the operating state of FIG. The orientation of the developing device 4 is changed so as to be on the side as in 1 (b), and the cover 42 is removed.

  As a result, the upper part of the stirring / conveying chamber 40B [the upper part in the operating state shown in FIG. 1 (a)] is opened.

  In the state of FIG. 1B, the developer D falls downward and is taken out from the developing device 4.

  However, the developer D is attracted to the developing roller 50 by the magnetic field formed by the magnetic pole S2 and the magnetic pole N2, and the developer D remains in the developing device 4 as illustrated.

  Since the residual developer D is adsorbed by magnetic force, it is difficult to remove, and even if the developer is replaced, the old developer occupies a considerable proportion of the developer in the developing device 4. Become.

  In Patent Document 1, when a developer is exchanged, a magnet roll in the developing roller is rotated so that a strong magnetic field is not formed in the developer take-out portion.

  However, when the method of Patent Document 1 is adopted, there is a case where the position of the magnetic pole on the developing roller is different from the position before replacement after the developer replacement.

  In the developing process, since the position of the magnetic pole affects the image quality, the magnetic pole position in the developing roller needs to be set with high accuracy.

  In Patent Document 1, in order to rotate the magnetic pole, advanced technology and a long time are required for adjustment for setting the magnetic pole position to the original position after the developer replacement.

  When the magnetic pole position is not appropriate, the image quality is deteriorated. When the magnetic pole position is significant, developer spillage may occur during operation of the image forming apparatus.

  The present invention solves the above-described problems in the prior art relating to developer replacement, and does not change the magnetic pole position in the developing roller due to developer replacement, and can perform developer replacement with simple work. The purpose is to provide.

  The object is achieved by the following invention.

1. A housing that houses the developer and occupies the bottom of the developing device ;
A cover that covers the top of the housing and is removable from the housing;
A developing roller disposed in a space formed by the housing and the cover; a developing chamber for supplying developer to the developing roller in the space formed by the housing and the cover; and replenished toner A partition member that divides the developer into a stirring / conveying chamber that mixes with the developer,
In the developing device that can be removed from the image forming apparatus main body,
The developing roller includes a rotating developing sleeve and a magnet roller having a peeling pole fixed to the housing within the developing sleeve and forming a repulsive magnetic field,
When the developing device is taken out from the image forming apparatus main body, the partition member is removable from the developing device together with the cover.
When the cover is removed from the housing, the partition member moves relative to the housing ;
The developing device according to claim 1, wherein the surface of the developing roller between the peeling electrodes is opened by the movement of the partition member .

2. When the cover is removed after the direction of the developing device is changed so that the housing is on the side, the surface of the developing roller between the peeling poles faces an open space, and the peeling pole 2. The developing device as described in 1 above, wherein the developer in between drops from the developing roller .

3 . An image forming apparatus comprising: an image bearing member; a latent image forming unit that forms a latent image on the image bearing member; and the developing device described in 1 or 2 above.

  In the present invention, the partition member that divides the inside of the developing device into the developing chamber and the stirring / conveying chamber is moved or movable when the developing device is taken out from the image forming apparatus main body.

  As a result, an opening for extracting the developer from the developing device is greatly opened.

  Therefore, the developer can be extracted from the developing device with a simple operation without changing the position of the magnetic pole.

  Hereinafter, the present invention will be described based on an embodiment of the present invention, but the present invention is not limited to the embodiment.

  FIG. 2 shows the overall configuration of an image forming apparatus having a developing device according to the present invention. The image forming apparatus includes an image forming apparatus main body GH, an image reading apparatus YS, and the like. The image forming apparatus main body GH is referred to as a tandem color image forming apparatus, and includes an image forming unit including a plurality of sets of image forming units 10Y, 10M, 10C, and 10K, an endless belt-shaped intermediate transfer body 6, and a secondary transfer. It comprises a roller 7A, a fixing device 9 and the like.

  An image reading device YS including an automatic document feeder 501 and a document image scanning exposure device 502 is installed on the image forming apparatus main body GH. The document d placed on the document table of the automatic document feeder 501 is transported by a transporting unit, and an image on one or both sides of the document is scanned and exposed by the optical system of the document image scanning exposure device 502, and is applied to the line image sensor CCD. Is read.

  A signal formed by photoelectric conversion by the line image sensor CCD is subjected to analog processing, A / D conversion, shading correction, image compression processing, and the like in an image processing unit, and then exposure devices 3Y, 3M, 3C, 3K. Sent to.

  The image forming unit 10Y that forms a yellow (Y) image includes a photosensitive drum 1Y as an image carrier, a charging unit 2Y, a developing device 4Y, a primary transfer roller 7Y, and a cleaning unit 8Y. The charging unit 2Y, the developing device 4Y, the primary transfer roller 7Y, and the cleaning unit 8Y are arranged around the photosensitive drum 1Y as illustrated.

  The image forming unit 10M that forms a magenta (M) color image includes a photosensitive drum 1M as an image carrier, a charging unit 2M, a developing device 4M, a primary transfer roller 7M, and a cleaning unit 8M. An image forming unit 10C for forming a cyan (C) color image includes a photosensitive drum 1C as an image carrier, a charging unit 2C, a developing device 4C, a primary transfer roller 7C, and a cleaning unit 8C. The image forming unit 10K that forms a black (Bk) image includes a photosensitive drum 1K as an image carrier, a charging unit 2K, a developing device 4K, a primary transfer roller 7K, and a cleaning unit 8K.

  The image forming units 10Y, 10M, 10C, and 10K can be individually attached to and detached from the main body of the image forming apparatus. The developing device 4Y can be taken out from the image forming unit 10Y taken out from the image forming apparatus main body, and the developing device 4M can be taken out from the image forming unit 10M taken out from the image forming apparatus main body. 4C can be taken out from the image forming unit 10C taken out from the main body of the image forming apparatus, and the developing device 4K can be taken out from the image forming unit 10K taken out from the main body of the image forming apparatus.

  An exposure apparatus 3Y for the image forming unit 10Y, an exposure apparatus 3M for the image forming unit 10M, an exposure apparatus 3C for the image forming unit 10C, and an exposure apparatus 3K for the image forming unit 10K are included in the image forming apparatus. It is fixedly installed.

  The charging unit 2Y and the exposure unit 3Y, the charging unit 2M and the exposure unit 3M, the charging unit 2C and the exposure unit 3C, and the charging unit 2K and the exposure unit 3K constitute a latent image forming unit that forms a latent image on the image carrier. .

  The developing devices 4Y, 4M, 4C, and 4K include a two-component developer including yellow (Y), magenta (M), cyan (C), and black (K) toner having a small particle diameter and a carrier.

  The intermediate transfer member 6 is stretched around a driving roller 61, a backup roller 62, a tension roller 63, and idler rollers 64 and 65, and forms a belt unit 60 that is long in the horizontal direction as shown in the figure.

  The backup roller 62 faces the secondary transfer roller 7A.

  The primary transfer rollers 7 </ b> Y, 7 </ b> M, 7 </ b> C, and 7 </ b> K are in contact with the horizontal portion of the intermediate transfer body 7.

  The fixing device 9 includes a fixing roller 93 and a pressure roller 94, and fixes the toner image on the recording paper P by heating and pressing at a nip portion formed between the fixing roller 93 and the pressure roller 94. .

  Each color image formed by the image forming units 10Y, 10M, 10C, and 10K is sequentially transferred and synthesized by the primary transfer rollers 7Y, 7M, 7C, and 7K on the rotating intermediate transfer body 6 to form a color toner image. Is done.

  The recording paper P stored in the paper supply tray 21 serving as the recording paper storage means is separated and fed by the paper supply roller 22 of the paper supply means 20, and is in a stopped state via the paper supply roller 23. The paper is fed to the registration roller 24. Therefore, once stopped, the registration roller 24 starts rotating at the timing when the positional relationship between the leading end and the toner image on the intermediate transfer body 6 exactly coincides, and is fed to the secondary transfer roller 7A. A color image is transferred onto the recording paper P (secondary transfer). The recording paper P to which the color toner image has been transferred is heated and pressurized by the fixing device 9 and the color toner image on the recording paper P is fixed. Thereafter, the sheet is sandwiched between the sheet discharge rollers 25 and placed on the sheet discharge tray 26 outside the apparatus.

  Reference numeral 27 denotes a re-feeding unit that conveys the recording paper P with the front and back reversed when forming the back side image.

  On the other hand, after the color toner image is transferred onto the recording paper P by the secondary transfer roller 7A, the residual toner is removed by the intermediate transfer body cleaning means 8A from the intermediate transfer body 6 from which the recording paper P is separated by curvature.

  FIG. 3 shows a developing device according to Embodiment 1 of the present invention.

  The developing devices 4Y, 4M, 4C, and 4K in FIG. 2 have the structure shown in FIG.

  In FIG. 3 and subsequent figures, the developing devices 4Y, 4M, 4C, and 4K are denoted by reference numeral 4. As described above, the developing device 4 is detachable from the image forming apparatus main body GH.

  FIG. 3A shows the developing device 4 mounted on the image forming apparatus main body GH and operating, and FIG. 3B shows the developing device 4 taken out of the image forming apparatus main body and changing the developer. Show. As shown in the figure, the housing 41 occupies the bottom of the developing device 4 and the cover 42 covers the top of the housing 41 when mounted.

  As described with reference to FIG. 1, the outer shape of the developing device 4 is formed by the housing 41 and the cover 42, and includes a developing roller 50, screws 51 and 52 as stirring and conveying means, a developer regulating member 53, A developer guide member 54 and the like are disposed. The inside of the developing device is divided into a developing chamber 40A and a stirring / conveying chamber 40B by a partition member 43.

  A developer is accommodated in the housing 41, and as described with reference to FIG. 1, the developer is supplied from the developing chamber 40A to the developing roller 50, and development is performed.

  The developing roller 50 includes a magnet roll fixed to a housing 41 having a plurality of magnetic poles and a developing sleeve that rotates as indicated by an arrow.

  The magnet roll has two north poles N1, N2 and three south poles S1, S2, S3.

  The N1 pole constitutes a developing pole, and S1 and S2 adjacent to the same pole form a repulsive magnetic field and constitute a peeling pole that separates the developer from the developing roll 51.

  In the developing device 4 shown in FIG. 3, the partition member 43 is integrally formed with the cover 42, and the partition member 43 is also removed from the developing device 4 together with the cover 42 in the state of FIG. It is.

  When the developer is deteriorated due to the image forming operation for a long time, the old developer is removed from the developing device 4 and the developer is replaced with a new developer.

  For this developer replacement, the developing device 4 is taken out from the image forming apparatus main body GH (shown in FIG. 2) by a user or a service person.

  When the image agent is exchanged, the developing device 4 is turned sideways as shown in FIG. That is, in the operating state of FIG. 3A, the orientation of the developing device 4 is changed so that the housing 41 occupying the bottom becomes the side as shown in FIG. 3B, and the cover 42 is removed.

  In FIG. 3B, both the cover 42 and the partition member 43 are removed from the developing device 4.

  As a result, the lower part of the developing roller 50 in FIG. As a result, the developer falls as indicated by an arrow W.

  In FIG. 3B, the surface of the developing roller 50 between the magnetic poles S1 and S2 constituting the peeling pole faces a space where it is open. Therefore, the developer between the peeling poles S1 and S2 falls away from the developing roller 50.

  In some cases, the developer is attached in the vicinity of the magnetic pole N2, but the attached developer is removed from the developing roller 50 by being brought between the magnetic pole S1 and the magnetic pole S2.

  As a result, most of the developer in the developing device 4 is removed.

  FIG. 4 shows a developing device 4 according to Embodiment 2 of the present invention.

  In the developing device 4 shown in FIG. 4, the head of the partition member 43 is supported by the cover 42 and fixed in the developing device 4 as shown in FIG. By removing the cover 42, as shown in FIG. 4B, the partition member 43 rotates around its base to open the developing chamber 40A.

  As a result, the developer falls as indicated by an arrow W.

  Also in the present embodiment, the surface of the developing roller 50 between the magnetic poles S <b> 1 and S <b> 2 constituting the peeling pole is released by the rotation of the partition member 43.

  As a result, the developer falls from the developing roller 50, and the old developer is efficiently removed.

  After the developer replacement, the developing device 4 is brought into the upright state shown in FIG. 4A, and the partition member 43 is returned to the state shown in FIG. Thus, the partition member 43 is fixed.

  FIG. 5 shows a developing device 4 according to Embodiment 3 of the present invention.

  The partition member 43 is biased upward in FIG. 5A by a spring (not shown). 5A, the upward movement is restricted by the cover 42, and the lower end of the partition member 43 is in contact with the housing 41 to form the developing chamber 40A and the stirring / conveying chamber 40B.

  As shown in FIG. 5B, by removing the cover 42, the partition member 43 is moved by the bias of the spring, and its end [the right end in FIG. A space 40 </ b> C is formed between the housing 41 and the housing 41.

  The developer falls through the interval 40C and is taken out from the developing device 4.

  Also in FIG. 5B, the surface of the developing roller 50 between the magnetic pole S1 and the magnetic pole S2 faces the interval 40C, and the developer is efficiently extracted.

It is a figure explaining the developer exchange in the conventional developing device. 1 is a diagram illustrating an overall configuration of an image forming apparatus having a developing device according to an embodiment of the present invention. It is a figure which shows the developing device which concerns on Embodiment 1 of this invention. It is a figure which shows the developing device which concerns on Embodiment 2 of this invention. It is a figure which shows the developing device which concerns on Embodiment 3 of this invention.

Explanation of symbols

4, 4Y, 4M, 4C, 4K Developing device 40A Developing chamber 40B Stirring / conveying chamber 41 Housing 42 Cover 43 Partition member 50 Developing roller

Claims (3)

A housing that houses the developer and occupies the bottom of the developing device ;
A cover that covers the top of the housing and is removable from the housing;
A developing roller disposed in a space formed by the housing and the cover; a developing chamber for supplying developer to the developing roller in the space formed by the housing and the cover; and replenished toner A partition member that divides the developer into a stirring / conveying chamber that mixes with the developer,
In the developing device that can be removed from the image forming apparatus main body,
The developing roller includes a rotating developing sleeve and a magnet roller having a peeling pole fixed to the housing within the developing sleeve and forming a repulsive magnetic field,
When the developing device is taken out from the image forming apparatus main body, the partition member is removable from the developing device together with the cover.
When the cover is removed from the housing, the partition member moves relative to the housing ;
The developing device according to claim 1, wherein the surface of the developing roller between the peeling electrodes is opened by the movement of the partition member . When the cover is removed after the direction of the developing device is changed so that the housing is on the side, the surface of the developing roller between the peeling poles faces an open space, and the peeling pole 2. The developing device according to claim 1, wherein the developer in between drops from the developing roller . An image forming apparatus comprising: an image bearing member; a latent image forming unit that forms a latent image on the image bearing member; and the developing device according to claim 1 .

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