JP2018010077A - Development device and image formation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress stain on an external wall surface of a housing storing a developer or an external wall surface of a shutter member due to the developer or toner.SOLUTION: A housing 140 storing a developer includes: a developer discharge cylinder 141a which is formed with a developer discharge port 148; a shutter member 200 which rotates while sliding with the inner wall surface of the developer discharge cylinder 141a; and a spring member 209 which biases the shutter member 200 so as to maintain the posture closing the developer discharge port 148. The developer discharge cylinder 141a forms a wall part 141c over the whole periphery and has an enlarged diameter part 141b with diameter enlarged in the step shape. The shutter member 200 includes: an auger 144 which is arranged in the enlarged diameter part 141b, extends through inside the developer discharge cylinder 141a, and makes the partial developer advance in the developer discharge cylinder 141a; and a helical gear 241 which transmits the rotary driving force to the auger 144 and presses the shutter member 200 to the wall part 141c.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a developing device and an image forming apparatus.

  A developing device that houses a developer containing toner and a carrier in a housing, develops the electrostatic latent image formed on the image carrier with the toner in the developer, and holds the toner image on the image carrier. Are known. This type of developing device is provided with a mechanism for circulating the developer contained in the housing while stirring. This developing device has a toner supply port that receives supply of toner in its housing in order to supplement the toner used for development. In addition, since the developer deteriorates by circulating while stirring the developer in the housing, in this type of developing device, a developer discharge port opened downward is provided in the housing, There is a developing device that employs a so-called trickle system that suppresses the deterioration of the developer by discharging the circulatingly moving developer little by little. There is also known a developing device having a detachable structure for inspection and repair or replacement.

  Here, in the case of the development device in which the developer discharge port is formed and detachable, the developer discharge port is set so that the developer or toner does not spill out from the developer discharge port when the development device is removed. A shutter member that can be freely opened and closed is provided.

  Various types of shutter members are known that open and close the developer or toner passages (see, for example, Patent Documents 1-3).

JP 2009-036952 A JP 2014-035504 A JP 2014-092597 A

  Consider a case in which a shutter member that closes the developer discharge port from the outer wall surface side of the housing is provided as a shutter member that closes the developer discharge port provided in the housing of the developing device. In this case, since the inner wall surface of the shutter member is in contact with the developer in the housing, the developer or toner is applied to the portion of the outer wall surface of the housing that slides with the shutter member as the shutter member opens and closes. There is a risk that problems such as staying attached and soiling the hands and clothes of an operator who attaches and detaches the developing device and soiling the inside of the image forming apparatus containing the developing device may occur.

  In order to avoid this, it is conceivable to provide a shutter for closing the developer discharge port from the inner wall surface side of the housing. However, even if a shutter that closes the developer discharge port from the inner wall surface side is provided, toner enters the gap between the housing and the shutter member, and the shutter member opens and closes from the developer discharge port as the shutter member opens and closes. There is a risk of sneaking around the outer wall facing the wall.

  In view of the above circumstances, the present invention includes a shutter member that closes the developer discharge port from the inner wall surface side of the housing so as to be freely opened and closed, and includes the pressing mechanism according to the present invention that presses the shutter member against the wall. It is an object of the present invention to provide a developing device and an image forming apparatus in which contamination of the outer wall surface of the casing or the outer wall surface of the shutter member due to the developer or toner is suppressed as compared with the case where the developer is not.

Claim 1
A housing for storing a developer containing toner and a carrier is provided, and the electrostatic latent image formed on the image carrier is developed with the toner in the developer to hold the toner image on the image carrier. A developing device,
The housing is
A developer discharge port that extends in a cylindrical shape and discharges the developer; and a part of the developer in the housing flows in; a developer discharge tube that discharges the flowed developer from the developer discharge port;
Rotating between an open position and a closed position while sliding on the inner wall surface of the developer discharge cylinder around the cylindrical central axis of the developer discharge cylinder disposed in the developer discharge cylinder, A shutter member having a shutter opening that communicates with the developer discharge port when in a posture, and closing the developer discharge port when in the closed posture;
A biasing member that biases the shutter member so that the closed posture is maintained;
The developer discharge cylinder forms a wall that extends around the circumference upstream of the developer discharge opening in the developer traveling direction in the developer discharge cylinder toward the developer discharge opening. An inner wall surface of the developer discharge cylinder has a diameter-enlarged portion that is enlarged in a step shape, and at least a rear end portion in the traveling direction of the shutter member is disposed in the enlarged-diameter portion, The developing device includes a pressing mechanism that presses the shutter member against the wall portion toward the upstream side in the traveling direction.

Claim 2
The developer extends through the developer discharge cylinder, and rotates to carry the developer in the casing in a direction opposite to the traveling direction, and a part of the developer passes through the developer discharge cylinder. A transport member that advances in the direction of travel;
A helical gear that transmits a rotational driving force to the conveying member;
The pressing mechanism presses the shutter member against the wall portion by transmitting to the shutter member a force in the rotation axis direction of the conveying member generated by a rotational driving force that rotates the helical gear. The developing device according to claim 1, wherein:

Claim 3
From the developer discharge port that opens only inside the developer discharge port when the shutter opening of the shutter member in the open posture is projected in the direction of the developer passing through the developer discharge port. The developing device according to claim 1, wherein the opening is a small opening.

Claim 4
A developing device according to any one of claims 1 to 3,
A developer housing that is detachably mounted to store the developer discharged from the developer discharge port;
A rotation operation member that rotates the shutter member in the closed posture to the open posture against the biasing by the biasing member;
A first image forming unit comprising the image carrier and forming an electrostatic latent image on the image carrier;
An image forming apparatus comprising: a second image forming unit configured to form an image derived from a toner image held on the image holding member on a sheet.

  According to the developing device of the first aspect and the image forming apparatus of the fourth aspect, the outer wall surface of the housing or the shutter member by the developer or the toner is compared with the case where the pressing mechanism for pressing the shutter member against the wall portion is not provided. Dirt on the outer wall of the can be suppressed.

  According to the developing device of claim 2, a pressing mechanism having a simple structure is configured as compared with a case where a power source for pressing the shutter member against the wall portion is provided separately from a power source for operating the conveying member. can do.

  According to the developing device of the second aspect, as compared with the case where the shutter member has a shutter opening having a size protruding from the opening of the developer discharging port or a protruding shape, the contamination of the developer discharging port is suppressed.

1 is a configuration diagram illustrating an embodiment of an image forming apparatus of the present invention. It is a top view of a developing device. It is sectional drawing which follows the arrow AA shown in FIG. It is a perspective view of a developing device. FIG. 5 is an enlarged view of a portion of a circle R2 shown in FIG. 4B of the developing device. FIG. 5 is an enlarged perspective view of a portion of a circle R1 shown in FIG. 4A of the developing device. It is sectional drawing which follows the arrow BB shown in FIG. FIG. 3 is a cross-sectional view of the developing device along the arrow CC shown in FIG. 2. FIG. 9 is an enlarged view of a portion of a circle R3 shown in FIG. FIG. 2 is a view showing an inner cover or the like that appears when a door (not shown) provided in the housing of the image forming apparatus shown in FIG. 1 is opened. FIG. 3 is a diagram illustrating a structure inside the inner cover of the image forming apparatus with the inner cover removed.

  Embodiments of the present invention will be described below.

  FIG. 1 is a configuration diagram showing an embodiment of an image forming apparatus of the present invention.

  In the image forming apparatus 1 shown in FIG. 1, image forming units 10Y, 10M, 10C, and 10K corresponding to yellow (Y), magenta (M), cyan (C), and black (K) colors are arranged in parallel. The tandem color printer is capable of printing a single color image and printing a full color image composed of four color toner images.

  The image forming apparatus 1 includes an exposure unit 20 that irradiates each of the image forming units 10Y, 10M, 10C, and 10K with exposure light, and an intermediate transfer in which toner images are transferred from the image forming units 10Y, 10M, 10C, and 10K of the respective colors. A belt 30, a secondary transfer device 50 for transferring the toner image from the intermediate transfer belt 30 to the paper, a fixing device 60 for fixing the toner to the paper, a belt cleaner 70 for collecting the toner from the intermediate transfer belt 30, and the paper. A paper transport unit 80 for transporting the paper and a paper container C for storing the paper P are provided. The image forming apparatus 1 also includes toner storage containers 18Y, 18M, 18C, and 18K that store toner of each color of YMCK, and toners in the toner storage containers 18Y, 18M, 18C, and 18K, as image forming units 10Y, 10M, and 10C. , 10K, and toner supply devices 19Y, 19M, 19C, and 19K, respectively.

  Since the four image forming units 10Y, 10M, 10C, and 10K have substantially the same configuration, the image forming unit 10Y corresponding to yellow will be described as a representative example here. The image forming unit 10Y includes a photoreceptor 11Y, a charger 12Y, a developing device 14Y, a primary transfer device 15Y, and a photoreceptor cleaner 16Y. The photoreceptor 11Y has a cylindrical surface, holds an image formed on the surface, and rotates in the direction of an arrow a around the axis of the cylinder. The photoreceptor 11Y corresponds to an example of the image carrier in the present invention. The same applies to the other photoconductors 11M, 11C, and 11K.

  The charger 12Y has a charging roll that rotates while contacting the photoconductor 11Y, and charges the surface of the photoconductor 11Y.

 A developer containing toner and a magnetic carrier is accommodated in the developing device 14Y. The developing device 14Y includes a developing roll 146Y, and the developing roll 146Y conveys the developer to the photoreceptor 11Y. The toner of the developer adheres to the photoconductor 11Y, whereby a toner image is formed on the photoconductor 11Y. New toner is replenished to the developing device 14Y by the toner container 18Y and the toner supply device 19Y. A toner transport mechanism (not shown) that is driven by the control of the control unit 1B is provided in the toner supply device 19Y.

  The primary transfer unit 15Y transfers the toner image to the intermediate transfer belt 30. The photoreceptor cleaner 16Y cleans the surface of the photoreceptor 11Y after transfer.

  The exposure device 20 emits exposure light based on an image signal supplied from the outside, and exposes the photoreceptors 11Y, 11M, 11C, and 11K with the emitted light.

  The intermediate transfer belt 30 is an endless belt-like member supported by belt support rolls 31, 32, 33, 34, and an arrow b passing through the image forming units 10 </ b> Y, 10 </ b> M, 10 </ b> C, 10 </ b> K and the secondary transfer unit 50. Move around in the direction indicated by. The intermediate transfer belt 30 holds toner images of the respective colors formed by the image forming units 10Y, 10M, 10C, and 10K.

  The secondary transfer device 50 is a roll that rotates with the intermediate transfer belt 30 and the paper sandwiched between it and the backup roll 34 that is one of the belt support rolls 31 to 34. A voltage that generates an electric field for transferring toner is supplied between the secondary transfer device 50 and the backup roll 34, and the toner image on the intermediate transfer belt 30 is transferred onto the sheet.

  The belt cleaner 70 brings a blade into contact with the intermediate transfer belt 30 to remove toner on the intermediate transfer belt 30.

  The fixing device 60 includes a heating roll 61 and a pressure roll 62, and fixes the toner image on the paper by passing the paper on which the toner image before fixing is formed.

  The paper transport unit 80 takes out the paper P from the paper container C and transports it along the paper transport path r passing through the secondary transfer device 50 and the fixing device 60. The paper transport unit 80 includes a pick-up roll 81 that picks up the paper P stored in the paper container C, a scooping roll 82 that picks up the picked-up paper P, a transport roll 83 that transports the paper P, and a secondary transfer device 50 that transports the paper P. A registration roll 84 that transports the paper P to the outside, a discharge roll 86 that discharges the paper P to the outside, and reversal transport rolls 88 and 89 that transport the paper P during double-sided printing.

  The basic operation of the image forming apparatus 1 shown in FIG. 1 will be described.

 In the yellow image forming unit 10Y, the photoconductor 11Y is rotationally driven in the direction of arrow a, and a charge is applied to the surface of the photoconductor 11Y by the charger 12Y. The same applies to the image forming units 10M, 10C, and 10K corresponding to colors other than yellow. The exposure device 20 irradiates the photoconductors 11Y, 11M, 11C, and 11K with exposure light corresponding to data corresponding to each color in the image signal. Here, yellow (Y) will be described as a representative. The exposure device 20 forms an electrostatic latent image on the surface of the photoconductor 11Y by irradiating the surface of the photoconductor 11Y with exposure light based on an image signal corresponding to yellow among image signals supplied from the outside. . The developing device 14Y forms a toner image by developing the electrostatic latent image with yellow toner. To the developing device 14Y, toner is supplied from the toner container 18Y by the toner supply device 19Y. The photoconductor 11Y rotates while holding the yellow toner image formed on the surface. The toner image formed on the surface of the photoreceptor 11Y is transferred to the intermediate transfer belt 30 by the primary transfer unit 15Y that applies a transfer potential between the photoreceptor 11Y and the intermediate transfer belt 30. After transfer, the toner remaining on the photoreceptor 11Y is collected and removed by the photoreceptor cleaner 16Y.

  The intermediate transfer belt 30 is supported by the support rolls 31 to 34 and cyclically moves in the direction of the arrow b. The image forming units 10M, 10C, and 10K corresponding to colors other than yellow are image forming units 10Y corresponding to yellow. Similarly, toner images corresponding to the respective colors are formed, and the toner images of the respective colors are transferred onto the intermediate transfer belt 30 so as to be superimposed on the toner images transferred by the image forming unit 10Y.

  On the other hand, the paper P in the paper container C is taken out by the pick-up roll 81, and the paper roll R is moved in the direction of the arrow c toward the secondary transfer device 50 by the separating roll 82, the transport roll 83, and the registration roll 84. Be transported. The sheet P is sent to the secondary transfer unit 50 at a timing when the toner image is transferred onto the intermediate transfer belt 30 by the registration roll 84. The secondary transfer device 50 transfers the toner image on the intermediate transfer belt 30 to the paper P by applying a transfer bias potential between the intermediate transfer belt 30 and the paper P. The paper P on which the toner image is transferred by the secondary transfer device 50 is conveyed to the fixing device 60, and the toner image transferred on the paper P is fixed. In this way, an image is formed on the paper P. The paper P on which the image is formed is discharged to the upper part of the image forming apparatus 1 by the discharge roll 86. The toner remaining on the intermediate transfer belt 30 after the transfer by the secondary transfer device 50 is removed by the belt cleaner 70.

  In the case of double-sided printing in which an image is also formed on the back side of a sheet on which an image is formed on the front side, the discharge roll 86 discharges the sheet P halfway from the sheet discharge port and then conveys it in the reverse direction. The sheet P conveyed in the reverse direction is conveyed by the reverse conveying rolls 88 and 89 via the reverse conveying path r '. The conveyed paper P is sent from the registration roll 84 to the secondary transfer unit 50 in a state where the front and back sides are reversed, and an image is also formed on the back side.

  FIG. 2 is a plan view of the developing device.

  The image forming apparatus 1 shown in FIG. 1 includes four developing devices 14Y, 14M, 14C, and 14K, all of which have substantially the same configuration. Therefore, in the description of FIG. 2 and subsequent figures, the symbols Y, M, C, and K representing the color of the toner are removed and the developing device 14 is simply referred to. The same applies to each component of the developing device 14. The same applies to components other than the developing device 14 when described with reference to FIG.

 FIG. 2 shows an upper surface of the developing device 14, and a housing 140 of the developing device 14 is formed with a toner supply port 147 that opens upward. Further, a developer discharge port is also formed in the casing 140 of the developing device 14, but this developer discharge port is an opening opened downward, and is not shown in FIG. The toner supply port 147 and the developer discharge port will be described later.

  FIG. 3 is a cross-sectional view taken along arrow AA shown in FIG.

  In the developing device 14, two housing chambers for containing a developer, which are a first chamber 141 and a second chamber 142, are provided in the housing 140. These two storage chambers (the first chamber 141 and the second chamber 142) are partitioned by a partition wall 143. The first chamber 141 is provided with a supply auger 144, and the second chamber 142 is provided with an admix auger 145. The supply auger 144 and the admix auger 145 both extend in a bar shape, and are arranged horizontally and parallel to each other. The supply auger 144 has a rotary shaft 144a having a circular cross section, and a spiral blade 144b extending in the direction of the rotary shaft 144a when swiveling around the rotary shaft 144a. Similarly to the supply auger 144, the admix auger 145 also has a rotating shaft 145a having a circular cross section, and a spiral blade 145b extending in the direction of the rotating shaft 145a if it rotates while drawing a spiral around the rotating shaft 145a. The supply auger 144 and the admix auger 145 are each provided with a spiral blade other than the spiral blades 144b and 145b, but description thereof is omitted here.

  The supply auger 144 and the admix auger 145 rotate in the directions of arrows e and f, which are shown in FIG. The spiral blade 144b of the supply auger 144 and the spiral blade 145b of the admix auger 145 are spiral blades swirling in opposite directions, and the supply auger 144 and the admix auger 145 are the same as shown by arrows e and f in FIG. When rotated in the direction, the developers in the first chamber 141 and the second chamber 142 are conveyed in opposite directions while being stirred. That is, the developer in the first chamber 141 in which the supply auger 144 is arranged is conveyed in the direction of the arrow g shown in FIG. 2 by the rotation of the supply auger 144 in the direction of the arrow e. 2 is conveyed in the direction of the arrow h shown in FIG. 2 by the rotation of the admix auger 145 in the direction of the arrow f.

  On the other hand, two windows (not shown) that connect the first chamber 141 and the second chamber 142 are formed at both ends of the partition wall 143 that partitions the first chamber 141 and the second chamber 142. Therefore, the developer in the first chamber 141 that has been transported in the direction of the arrow g flows into the second chamber 142 through one window, and the developer in the second chamber 142 that has been transported in the direction of the arrow h. The developer flows into the first chamber 142 through the other window. In this way, the developer in the developing device 14 circulates while being stirred in the first chamber 141 and the second chamber 142.

  Here, as shown in FIG. 3, the floor surface of the first chamber 141 is located higher than the floor surface of the second chamber 142. For this reason, when the developer in the first chamber 141 flows into the second chamber 142, the developer flows down into the second chamber 142. On the other hand, when the developer in the second chamber 142 flows into the first chamber 141, the developer is pushed up into the first chamber 141. In the developing device 14 of the present embodiment, the first chamber 141 and the second chamber 142 are arranged obliquely in this manner, thereby suppressing the width dimension of the developing device 14, reducing the size of the developing device 14, and forming an image. This contributes to downsizing of the device 1.

 The developing device 14 includes a developing roll 146 at a position adjacent to the first chamber 141 in which the supply auger 144 is disposed. A part of the developing roll 146 is exposed from the housing 140. The developing device 14 is provided in the image forming apparatus 1 (see FIG. 1) so that the exposed portion of the developing roll 146 is close to the photoreceptor 11.

 The developing roll 146 causes the developer in the first chamber 141 to adhere to the surface of the first chamber 141 by a magnetic force, rotates in the direction of the arrow d, and conveys the developer to a position facing the photoconductor 11. Then, the electrostatic latent image formed on the surface of the photoconductor 11 is developed with toner in the developer, and a toner image is formed on the surface of the photoconductor 11. On the other hand, the developer adhering to the surface of the developing roll 146 after developing with the toner returns to the inside of the housing 140 as the developing roll 146 rotates, leaves the developing roll 146, and is in the first chamber 141. It is stirred together with other developers while circulating.

 When the development with toner as described above is repeated, the toner in the developer inside the developing device 14 decreases. Therefore, the developing device 14 is provided with a toner supply port 147 (see FIG. 2) for receiving toner, and the toner in the toner container 18 shown in FIG. To be supplied. The toner supply port 147 is further upstream of the second chamber 142 in which the admix auger 145 is disposed than the window through which the developer flows from the first chamber 141 (the direction opposite to the direction indicated by the arrow h). Is provided. The admix auger 145 extends to a position where the toner supply port 147 is provided, and the toner supplied from the toner supply port 147 is conveyed downstream (in the direction indicated by the arrow h) in the second chamber 142. Thus, the developer that has flowed in through the window of the partition wall 143 merges and is conveyed further downstream (in the direction indicated by the arrow h) in the second chamber 142.

 FIG. 4 is a perspective view of the developing device. Here, FIG. 4A is a perspective view showing the shape of the developing device 14 when viewed from the direction in which the upper surface appears. FIG. 4B is a perspective view showing the shape of the developing device 14 as viewed from the direction in which the lower surface appears.

 FIG. 5 is an enlarged view of the portion of a circle R2 shown in FIG. 4B of the developing device.

 In FIG. 4B and FIG. 5, a developer discharge port 148 appears. The developer discharge port 148 is an opening that is provided on the lower surface of the housing 140 of the developing device 14 and opens downward. The developer discharge port 148 is provided in the most upstream portion of the first chamber 141 in which the supply auger 144 is disposed in the developer transport direction (the direction indicated by the arrow g in FIG. 2). That is, the developer conveyed in the second chamber 142 in which the admix auger 145 is disposed in the direction indicated by the arrow h in FIG. 2 passes through the window provided in the partition wall 143 and is in the first chamber 141. However, the developer discharge port 148 is provided at a position further upstream from the window in the developer transport direction (the direction indicated by the arrow g in FIG. 2). In addition to the spiral blade 144b, the supply auger 144 arranged in the first chamber 141 transports the developer flowing into the first chamber 141 in the direction indicated by the arrow g in FIG. A spiral blade 144c (see FIG. 8) is provided that turns in a direction opposite to the spiral turning direction of the spiral blade 144b. For this reason, a part of the developer flowing into the first chamber 141 is pushed in the direction opposite to the direction indicated by the arrow g by the spiral blade 144c and further moved to the upstream side, and the developer discharge port 148 To the outside of the developing device 14. In this way, the developer in the developing device 14 is discharged little by little from the developer discharge port 148, thereby suppressing excessive progress of deterioration due to stirring and conveyance of the developer in the developing device 14. Yes. From the developer discharge port 148, not only the toner but also the carrier is discharged together. For this reason, the toner supplied from the toner supply port 147, that is, the toner in the toner storage container 18 (see FIG. 1) includes a small amount of carrier to compensate for the decrease in carrier.

  The developing device 14 is configured to be detachably attached to the main body of the image forming apparatus 1 shown in FIG. For this reason, the developing device 14 includes a shutter member 200 (FIGS. 7 and 9) that closes the developer discharge port 148 so as not to fall off from the developer discharge port 148 when the developing device 14 is detached. See). When removing the developing device 14 from the image forming apparatus 1, an operation (described later) for closing the shutter member 200 and closing the developer discharge port 148 is performed, and the operation lever 149 in the horizontal posture shown in FIG. Turn 90 ° to the vertical position. When the operation lever 149 is operated so as to be in the vertical orientation, the developing device 14 is slightly separated from the photoconductor 11 (see FIGS. 1 and 3). In this way, the developer discharge port 148 is closed by the shutter member 200, and the developing device 14 is separated from the photosensitive member 11 by operating the operating lever 149 to be in the vertical orientation, and then the developing device 14 Is pulled out in the direction of the arrow h shown in FIG. In this way, the developing device 14 can be removed from the image forming apparatus 1.

  When the developing device 14 is attached to the image forming apparatus 1, an operation opposite to that for removing is performed. That is, the developing device 14 is inserted into the main body of the image forming apparatus 1 in the direction of the arrow g shown in FIG. 4 with the operation lever 149 in the vertical orientation. Once inserted, the operation lever 149 is operated so as to be in the horizontal posture shown in FIG. Further, an operation of opening the shutter member 200 closing the developer discharge port 148 is performed. The opening / closing operation of the shutter member 200 will be described later.

  FIG. 6 is an enlarged perspective view of a portion of a circle R1 shown in FIG. 4A of the developing device. Here, FIG. 6 (A) is an enlarged view of the portion of the circle R1, and FIG. 6 (B) is the gear cover shown in FIGS. 4 (A) and 6 (A). It is the figure which showed the gear 241 which removed 240 and was covered with the gear cover 240.

  FIG. 6 shows a portion of the shutter member 200 that blocks the developer discharge port 148 (see FIG. 4) that appears on the outer surface of the developing device 14.

 The shutter member 200 is a substantially cylindrical member disposed at the most upstream end of the first chamber 141 (see FIG. 3) in the developer transport direction (the direction indicated by the arrow g in FIG. 2). . The portion of the first chamber 141 where the shutter member 200 is disposed also has a substantially cylindrical inner wall surface. The shutter member 200 rotates with the supply auger 144 while sliding on the inner wall surface of the first chamber 141. The developer discharge port 148 is opened and closed by rotating around an axis.

 The shutter member 200 includes an opening / closing lever 201 shown in FIG. 6, and a spring member 209 is connected to the opening / closing lever 201. The open / close lever 201 shown in FIG. 6 is pushed downward by a member (not shown) on the main body side of the image forming apparatus 1. At this time, the spring member 209 is in an extended state, and the shutter member 200 is in a posture in which the developer discharge port 148 is opened. The operation of closing the shutter member 200 described above is an operation of releasing the opening / closing lever 201 from the member by releasing the opening / closing lever 201 by the member on the main body side of the image forming apparatus 1. When the opening / closing lever 201 is released, the spring member 209 is contracted, and the shutter member 200 is rotated accordingly, and the developer discharge port 148 is closed. That is, when the developing device 14 is detached from the image forming apparatus 1, the force from the member on the main body side does not act on the opening / closing lever 201 of the shutter member 200, and the shutter member 200 is attached to the spring member 209. The posture of closing the developer discharge port 148 by the force is maintained. When the developing device 14 is mounted on the image forming apparatus 1 and an operation of opening the developer discharge port 148 is performed, the member on the main body side rotates the opening / closing lever 201 against the biasing force of the spring member 209, The state where the open / close lever 201 is pushed down is maintained. Thereby, the shutter member 200 maintains a posture in which the developer discharge port is opened.

 Further, the gear 241 shown in FIG. 6B rotates by receiving a rotational driving force from a driving source (not shown), and has a role of rotating the supply auger 144 and the admixing auger 145. These gears 241 are helical gears, and generate forces in the direction of the rotation axis when rotated. The pressing mechanism in the present embodiment uses a force in the direction of the rotation axis by the helical gear. Details will be described later.

 7 is a cross-sectional view taken along arrow BB shown in FIG.

 FIG. 7 shows the developer discharge port 148 and the shutter member 200. The developer discharge port 148 is provided in the uppermost stream portion of the first chamber 141 of the housing 140 of the developing device 14. In addition, the shutter member 200 is a member that is disposed in the most upstream portion of the first chamber 141. In the first chamber 141, the most upstream portion 141a (see also FIG. 8) where the developer discharge port 148 is provided and the shutter member 200 is disposed is a portion of the developer discharge cylinder referred to in the present invention. It corresponds to an example.

 As shown in FIG. 7, the most upstream portion 141a has an inner wall surface with a circular cross section. Further, the shutter member 200 disposed therein also has an outer wall surface and an inner wall surface having a circular cross section. The shutter member 200 is coaxial with the rotating shaft 144a of the supply auger 144 while sliding with the inner wall surface of the portion 141a on the most upstream side of the first chamber 141 in the opening / closing operation for opening and closing the developer discharge port 148. Rotate.

  The shutter member 200 shown in FIG. 7 is in the “open posture” with the developer discharge port 148 opened. The shutter member 200 has a shutter opening 207. When the shutter member 200 is in the open posture shown in FIG. 7, the shutter opening 207 is in a position communicating with the developer discharge port 148. Here, the shutter opening 207 is narrower than the width of the developer discharge port 148 and is disposed inside the developer discharge port 148 when in the open position shown in FIG. . For this reason, the developer falling to the developer discharge port 148 through the shutter opening 207 falls below the developer discharge port 148 without causing the wall surface of the developer discharge port 148 to be almost stained with the developer or toner. The developer that has dropped down is conveyed in the direction indicated by the arrow i in FIG. 11 in the waste toner conveyance cylinder 306 shown in FIG.

  FIG. 8 is a cross-sectional view of the developing device taken along the arrow CC shown in FIG.

  In FIG. 8, the supply auger 144 is shown over its entire length. In the first chamber 141 in which the supply auger 144 is arranged, a window (partition wall 143 formed in the vicinity of the spiral blade 144c of the supply auger 144 from the second chamber (see FIG. 3) ( The developer flows through (not shown). The spiral blade 144c is a spiral blade swirling in the opposite direction to the spiral blade 144b that conveys the developer flowing into the first chamber 141 downstream (in the direction indicated by the arrow g), and has flowed in from the second chamber 142. A part of the developer is pushed further upstream by the spiral blade 144 c, and a part of the developer is discharged from the developer discharge port 148 through the most upstream portion 141 a of the first chamber 141.

  FIG. 9 is an enlarged view of a portion of a circle R3 shown in FIG.

  FIG. 9 shows an axial cross section of the shutter member 200. In the most upstream portion 141a of the first chamber 141, a diameter-expanded portion 141b whose inner wall surface is expanded stepwise over the entire circumference is formed. The shutter member 200 is disposed in the enlarged diameter portion 141b. Then, by forming this enlarged diameter portion 141, the traveling direction of the developer traveling toward the developer discharge port 148 (the direction opposite to the arrow g shown in FIG. 8, the direction of the arrow h shown in FIG. 9). In this regard, a wall portion 141c is formed on the upstream side of the developer discharge port 148. The height of the wall 141c is the same as the thickness of the portion of the shutter member 200 in the vicinity of the upstream end face 205. For this reason, the inner wall surface of the portion upstream of the diameter-enlarged portion 141b of the portion 141a on the most upstream side of the first chamber 141 and the inner wall surface of the portion in the vicinity of the end surface 205 upstream of the shutter member 200 are flush with each other. It has become. Further, a groove 206 that is recessed over the entire circumference is formed on the outer wall surface of the shutter member 200, and an O-ring-like seal member 208 is fitted in the groove. This seal member is also in contact with the inner wall surface of the enlarged diameter portion 141b. This seal member 208 is a member for ensuring that the toner in the developer does not leak to the gear 241 side through the gap between the inner wall surface of the enlarged diameter portion 141b and the shutter member 200. .

  Here, when the gear 241, which is a helical gear, receives a rotational driving force, a force in the rotational axis direction of the supply auger 144 is generated. Here, the rotation direction of the teeth of the helical gear is determined so that the rotation of the gear 241 generates a force opposite to the direction indicated by the arrow h. When the gear 241 rotates, the interposed member 242 is pressed by the force generated in the direction of the rotation axis, and the shutter member 200 is further pressed through the interposed member 242. As a result, the upstream end surface 205 of the shutter member 200 is abutted against the wall 141c, and no gap is formed between the wall 141c and the end surface 205 of the shutter member 200.

  If a gap is formed between the wall 141c and the end surface 205 of the shutter member 200, the toner in the developer enters the gap, and the toner that has entered the gap as the shutter member 200 is opened and closed. However, there is a possibility that the shutter member 200 may wrap around the surface facing the outside of the developing device 14. In the case of the developing device 14 of the present embodiment, the upstream end surface 205 of the shutter member 200 is abutted against the wall portion 141c using the force in the rotation axis direction generated by the rotation of the gear 241 and the wall portion 141c and the shutter are pressed. A gap is not formed between the end surface 205 of the member 200. For this reason, there is almost no possibility that the internal toner will wrap around the surface of the shutter member 200 facing the outside of the developing device 14, and the contamination by the toner on the surface facing the outside is suppressed to a sufficiently low level. Yes.

  The gear 241 fixed to the supply auger 144 in this embodiment corresponds to an example of a helical gear referred to in the present invention, and the shutter member 200 is moved using the force generated as the gear 241 rotates. The structure pressed against the wall 141c corresponds to an example of a pressing mechanism according to the present invention. The supply auger 144 corresponds to an example of a conveying member according to the present invention.

  Further, the shutter opening 207 provided in the shutter member 200 is narrower than the dimension of the developer discharge port 148 in the longitudinal direction shown in FIG. 9 as well as in the width direction of the developing device 14 shown in FIG. When the shutter member 200 is in an open position with the developer discharge port 148 shown in FIG. 9 open, the shutter member 200 is opened only inside the developer discharge port 148. That is, the shutter opening 207 is narrower than the developer discharge port 148 in both the longitudinal direction shown in FIG. 9 and the width direction shown in FIG. It is an opening that opens only inside the developer discharge port 148 when projected in the direction of passage of the developer that passes through 148 and falls. Therefore, as described with reference to FIG. 7, the developer that has dropped to the developer discharge port 148 through the shutter opening 207 develops the wall surface of the developer discharge port 148 with almost no developer or toner. It falls further below the agent discharge port 148.

  FIG. 10 is a view showing an inner cover or the like that appears when a door (not shown) provided in the housing of the image forming apparatus shown in FIG. 1 is opened.

  FIG. 10 shows an operation handle 302 and a waste toner tank 303 in addition to the inner cover 301. The operation handle 302 is an operator that is operated when the developing device 14 is detached from the image forming apparatus 1 and when the developing device 14 of the image forming apparatus 1 is mounted. When the developing device 14 is attached to the image forming apparatus 1 and the image forming apparatus 1 is operating, the operation handle 302 is in a state of being rotated in the direction of the arrow k. FIG. 10 shows the operation handle 302 that is rotated in the direction of the arrow k. When the developing device 14 is taken out from the image forming apparatus 1, the operation handle 302 is rotated in the direction of the arrow j. Then, the shutter member 200 rotates and shifts to a “closed posture” in which the developer discharge port 148 is closed. On the contrary, when the developing device 14 is attached to the image forming apparatus 1, the operation handle 302 is rotated in the direction of the arrow k. Then, the shutter member 200 is rotated to be in the “open posture” in which the developer discharge port 148 is opened.

  The inner cover 301 is detachably attached to a main body frame (not shown) of the image forming apparatus 1 by a snap fit.

  FIG. 11 is a view showing a structure inside the inner cover of the image forming apparatus with the inner cover removed.

  Here, there are shown a rack 304 and a total of eight pinion gears 305 that are arranged in two upper and lower stages and mesh with the rack 304. When the operation handle 302 is rotated in the direction of arrow j, the rack 304 moves in the direction of arrow m, and the pinion gears 305 that mesh with the rack 304 rotate in the direction of arrow p, respectively. The upper four pinion gears 305 are gears for opening and closing a shutter member (not shown) of the photoreceptor cleaner 16 (see FIG. 1). In the image forming apparatus 1 of the present embodiment, not only the developing device 14 but also the photosensitive member 11 and the photosensitive member cleaner 16 are unitized, and the unit is also detachable. For this reason, a shutter member is provided that opens and closes an opening for discharging the waste toner collected by the photoconductor cleaner 16. The unit including the photoconductor 11 and the photoconductor cleaner 16 and the shutter member provided in the photoconductor cleaner 16 are not the theme of this embodiment, and further description thereof is omitted here.

  The four pinion gears 305 on the lower side are gears that open and close the shutter member 200 that opens and closes the developer discharge port 148 of the developing device 14. When the operation handle 302 is in the posture rotated in the direction of the arrow k, the opening / closing lever 201 shown in FIG. 6 of the shutter member 200 is in a state of being pushed to the posture shown in FIG. In this state, the spring member 209 is in an extended state, and the shutter member 200 is in an open posture with the developer discharge port 148 opened. When the operation handle 302 shown in FIGS. 10 and 11 is rotated in the direction of the arrow j, the pinion gear 305 rotates in the direction of the arrow p, and the opening / closing lever 201 of the shutter member 200 is connected to the lower pinion gear 305. A member (not shown) that pushes down moves in a direction to loosen the presser of the opening / closing lever 201, and the shutter member 200 rotates to a closed posture in which the developer discharge port 148 is blocked by the biasing force of the spring member 209. When the developing device 14 is taken out, the developing device 14 is further pulled out after operating the operation lever 149 so as to be in the vertical orientation. On the contrary, when the developing device 14 is mounted, the operation lever 149 is operated so as to be in a horizontal posture. Further, the inner cover 301 (see FIG. 10) is attached, and the operation lever 303 is rotated in the direction of the arrow k. Then, the rack 304 and the pinion gear 305 shown in FIG. 11 move or rotate in directions opposite to the arrows m and p shown in FIG. By this operation, the opening / closing lever 201 shown in FIG. 6 of the shutter member 200 is pushed down to the posture shown in FIG. Accordingly, the shutter member 200 rotates and the shutter opening 207 communicates with the developer discharge port 148, that is, the shutter member 200 is in the open posture with the developer discharge port 148 opened.

  The developer discharged from the developer discharge port 148 to the outside of the developing device 14 falls into the waste toner conveying cylinder 306 having a hollow cylindrical shape inside. The waste toner collected by the photoreceptor cleaner 16 (see FIG. 1) also flows into the waste toner conveying cylinder 306, and the waste toner collected from the intermediate transfer belt 30 by the belt cleaner 70 (see FIG. 1). Also flows in. The waste toner and developer that have flowed into the waste toner transport cylinder 306 are transported in the direction of arrow i by a transport member (not shown) disposed in the waste toner transport cylinder 306 to be discharged into the waste toner tank 303. To be recovered. When the waste toner tank 303 becomes full, the user replaces it with an empty waste toner tank 303.

 Here, the example in which the present invention is applied to the developing device 14 provided in the so-called tandem image forming apparatus 1 shown in FIG. 1 has been described. However, the present invention is an image forming apparatus of the type shown in FIG. For example, it may be a monochrome printer or the like, and can be applied to various types of image forming apparatuses.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10 Image forming part 11 Photoconductor 14 Developing apparatus 140 Housing | casing 141 1st chamber 141a The most upstream part 141b of a 1st chamber The enlarged diameter part 141c Wall part 142 The 2nd chamber 143 Partition wall 144 Supply auger 144a Rotation Shafts 144b, 144c Spiral blade 145 Admixed auger 145a Rotating shaft 145b Spiral blade 146 Development roll 147 Toner supply port 148 Developer discharge port 200 Shutter member 201 Opening / closing lever 205 End surface 206 on the upstream side of the shutter member Groove recessed over the entire circumference 207 Shutter opening 208 Seal member 209 Spring member 240 Gear cover 241 Gear 301 Inner cover 302 Operation handle 303 Waste toner tank 304 Rack 305 Pinion gear 306 Waste toner conveying cylinder

Claims (4)

A housing for storing a developer containing toner and a carrier is provided, and the electrostatic latent image formed on the image carrier is developed with the toner in the developer to hold the toner image on the image carrier. A developing device,
The housing is
A developer discharge port that extends in a cylindrical shape and discharges the developer; and a part of the developer in the housing flows in; a developer discharge tube that discharges the flowed developer from the developer discharge port;
Rotating between an open position and a closed position while sliding on the inner wall surface of the developer discharge cylinder around the cylindrical central axis of the developer discharge cylinder disposed in the developer discharge cylinder, A shutter member having a shutter opening that communicates with the developer discharge port when in a posture, and closing the developer discharge port when in the closed posture;
A biasing member that biases the shutter member so that the closed posture is maintained;
The developer discharge cylinder forms a wall that extends around the circumference upstream of the developer discharge opening in the developer traveling direction in the developer discharge cylinder toward the developer discharge opening. An inner wall surface of the developer discharge cylinder has a diameter-enlarged portion that is enlarged in a step shape, and at least a rear end portion in the traveling direction of the shutter member is disposed in the enlarged-diameter portion, The developing device includes a pressing mechanism that presses the shutter member against the wall portion toward the upstream side in the traveling direction. The developer extends through the developer discharge cylinder, and rotates to carry the developer in the casing in a direction opposite to the traveling direction, and a part of the developer passes through the developer discharge cylinder. A transport member that advances in the direction of travel;
A helical gear that transmits a rotational driving force to the conveying member;
The pressing mechanism presses the shutter member against the wall portion by transmitting to the shutter member a force in the rotation axis direction of the conveying member generated by a rotational driving force that rotates the helical gear. The developing device according to claim 1.   From the developer discharge port that opens only inside the developer discharge port when the shutter opening of the shutter member in the open posture is projected in the direction of the developer passing through the developer discharge port. The developing device according to claim 1, wherein the opening is a small opening. A developing device according to any one of claims 1 to 3,
A developer housing that is detachably mounted to store the developer discharged from the developer discharge port;
A rotation operation member that rotates the shutter member in the closed posture to the open posture against the biasing by the biasing member;
A first image forming unit comprising the image carrier and forming an electrostatic latent image on the image carrier;
An image forming apparatus comprising: a second image forming unit that forms an image derived from a toner image held on the image holding member on a sheet.

Images