JP2017219773A - Developing device, process cartridge, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device that can suppress the occurrence of unevenness in density of an image occurring due to deviation of the amount of developer in the longitudinal direction of a developer carrier, a process cartridge, and an image forming apparatus.SOLUTION: A developing device comprises: a developer carrier 12a that carries a developer on its surface and supplies the developer to an image carrier arranged opposite thereto; and a columnar developer regulating member 12d that is arranged opposite to the developer carrier with a predetermined gap and regulates the amount of developer carried on the developer carrier. The developer regulating member can be rotated on a shaft.SELECTED DRAWING: Figure 7

Description

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

  2. Description of the Related Art Conventionally, a developing device that includes a developer regulating member that is disposed to face a surface of a developer carrying member with a gap and regulates the amount of developer conveyed to a developing region is known.

  For example, Patent Document 1 describes the following developing device. This developing device is disposed oppositely with a predetermined gap between a developing roll, which is a developer carrying member that rotates with a developer carried on the surface, and the developing roll, and is carried on the developing roll. A cylindrical developer regulating member for regulating the developer amount is provided. The developer regulating member is disposed so as to extend along the rotation axis of the developing roll, and both ends thereof are supported in a non-rotatable manner by a housing that accommodates the developing roll and the like. Then, the developer carried on the developing roll by the rotation of the developing roll hits the developer regulating member, thereby regulating the layer thickness of the developer on the developing roll.

  However, in the developing device of Patent Document 1, the developer regulating member is bent, and the gap between the developer regulating member and the developing roll becomes uneven in the longitudinal direction of the developing roll, so that the developing roll regulated by the developer regulating member. There is a risk of deviation in the developer amount in the longitudinal direction of the developing roll. If the developer amount on the developing roll is deviated in the longitudinal direction of the developing roll, the density unevenness of the image occurs.

In order to solve the above-described problems, the present invention provides a developer carrier between a developer carrier that carries a developer on a surface and supplies the developer to an image carrier that is disposed opposite to the developer carrier. In a developing device provided with a cylindrical developer regulating member that is disposed to face each other with a predetermined gap and regulates the amount of developer carried on the developer carrying member.
The developer regulating member is rotatable about the axis.

  According to the present invention, it is possible to suppress the occurrence of uneven density in an image caused by a deviation in the developer amount in the longitudinal direction of the developer carrier.

1 is a schematic configuration diagram illustrating a copier that is an example of an image forming apparatus according to an exemplary embodiment. (A) is a perspective view of a process cartridge provided in the copier, and (b) is a cross-sectional view of the process cartridge. FIG. 2 is a perspective view showing an appearance of a developing device provided in the process cartridge. The perspective view which shows the state which decomposed | disassembled the upper casing and lower casing of the developing device. The figure which shows typically the circulation path | route of the developer in the developing device. FIG. 2 is a schematic sectional view of the developing device. FIG. 3 is a diagram illustrating an example of a developing roller and a developing doctor provided in the developing device. The figure which shows the bending state of the developing doctor. The figure which shows the other bending state of the developing doctor. The figure which shows the further another bending state of the developing doctor. The figure which shows an example of the edge part of the developing doctor.

Hereinafter, an embodiment in which the present invention is applied to a copying machine 500 that is an electrophotographic image forming apparatus will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram illustrating a copying machine 500 which is an example of an image forming apparatus according to the present embodiment.
FIG. 2A is a perspective view of the process cartridge 1, and FIG. 2B is a cross-sectional view of the process cartridge 1.
As shown in FIG. 1, an image reading apparatus 200 is attached to the upper part of the apparatus main body 100 of a copier 500 as an image forming apparatus. A process cartridge 1 is provided inside the apparatus main body 100.

  As shown in FIG. 2B, the process cartridge 1 includes a photosensitive member 10 as a latent image carrier, a charging device 11 as a process unit that is arranged around the photosensitive member 10 and acts on the photosensitive member 10, and development. The apparatus 12 and the cleaning apparatus 14 are provided. The process cartridge 1 is detachably attached to the apparatus main body 100. Since the photosensitive member 10, the charging device 11, the developing device 12, and the cleaning device 14 are unitized as the process cartridge 1, replacement and maintenance work is facilitated. Further, it is possible to maintain the positional accuracy between the members with high accuracy, and to improve the quality of the formed image.

  The charging device 11 as a charging unit is applied with a charging bias, applies a charge to the surface of the photoconductor 10 to uniformly charge the photoconductor 10, and a deposit such as toner attached to the surface of the charge roller 11 a. And a removing roller 11b for removing water.

  The developing device 12 as a developing unit includes a first agent storage chamber V1 and a second agent storage chamber V2. A first transport screw 12b as a developer transport unit is disposed in the first agent storage chamber V1. In the second agent storage chamber V2, a second conveying screw 12c as a developer conveying portion, a developing roller 12a as a developer carrying member, a developing doctor 12d as a developer regulating member, and the like are disposed.

In these two agent storage chambers V1 and V2, a developer which is a two-component developer including a magnetic carrier and a negatively chargeable toner is included. The first transport screw 12b is rotationally driven by a driving unit to transport the developer in the first agent storage chamber V1 to the front side in FIG. Then, the developer transported to the front side end portion in FIG. 2B of the first agent storage chamber V1 by the first transport screw 12b enters the second agent storage chamber V2.
The 2nd conveyance screw 12c in the 2nd agent storage chamber V2 is rotated by a drive means, and conveys a developer to the back side in Drawing 2 (b). In this manner, a developing roller 12a as a developer carrying member is disposed in a posture parallel to the second conveying screw 12c above the second conveying screw 12c that conveys the developer. The developing roller 12a includes a magnet roller fixedly disposed in a developing sleeve made of a non-magnetic sleeve that is rotationally driven.

  A part of the developer conveyed by the second conveying screw 12c is carried on the surface of the developing roller 12a by the rotational force of the rotating second conveying screw 12c and the magnetic force of the magnet roller in the developing roller 12a. Then, after the layer thickness is regulated by a developing doctor 12d as a developer regulating member composed of a round bar arranged so as to maintain a predetermined gap from the surface of the developing roller 12a, the development facing the photoreceptor 10 is performed. It is conveyed to the area and adheres to the electrostatic latent image on the photoreceptor 10. By this adhesion, a toner image is formed on the photoreceptor 10. The developer that has consumed toner by the development is returned to the second conveying screw 12c as the surface of the developing roller 12a moves. And it is conveyed by the 2nd conveyance screw 12c to the edge part of the 2nd agent storage chamber V2, and returns in the 1st agent storage chamber V1. In this way, the developer is circulated and conveyed in the developing device.

  Further, in the developing device 12, a toner concentration sensor 124 (see FIG. 5) for detecting the toner concentration of the developer is installed in the first agent storage chamber V1. The toner concentration sensor 124 measures the toner concentration of the developer from the magnetic permeability of the developer. When the toner concentration is lowered, the magnetic carrier is concentrated, so that the magnetic permeability is increased. When the value measured by the toner density sensor 124 exceeds the target value (threshold value), toner is supplied from the toner bottle 20 as the toner container shown in FIG. Is controlled to a constant concentration. The target value is determined based on the detection result obtained by detecting the toner adhesion amount of the toner pattern (reference pattern) formed on the photoconductor 10 in advance with an optical sensor.

  Such an operation is controlled so as to keep the reference pattern density on the photosensitive member constant. However, when the toner in the toner bottle 20 runs out, the reference pattern density drop cannot be suppressed. In such a situation where the reference pattern density is lowered, the detection result of the toner pattern by the optical sensor is not improved despite the operation of supplying the toner from the toner bottle 20 for a predetermined period. Therefore, if the toner pattern detection result by the optical sensor is not improved despite the operation of replenishing the toner from the toner bottle 20, it is determined that the toner has run out (toner end) (or estimation determination). To do.

  The cleaning device 14 as a cleaning unit includes a cleaning blade 14 a that contacts the surface of the photoconductor 10 and scrapes off transfer residual toner attached to the photoconductor 10. The collected toner collected by the cleaning blade 14a is accommodated in the collecting unit W, and the collecting unit W includes a toner collecting coil 14b that conveys the collected toner. The collected toner conveyed by the toner collecting coil 14b is conveyed to the developing device 12 by the toner conveying device. The collected toner that has been conveyed may be conveyed to the waste toner bottle 41. Further, the toner may be conveyed to the developing device 12 or the waste toner bottle 41 according to the superiority or inferiority of the developer.

  As shown in FIG. 1, the transfer device 17 as a transfer unit includes a transfer roller 16, and the transfer roller 16 is pressed against and contacted with the peripheral surface of the photoconductor 10. A thermal fixing device 24 as a fixing unit is provided above the transfer device 17. The thermal fixing device 24 includes a heating roller 25 and a pressure roller 26. Further, the apparatus main body 100 includes a laser writing device 21 as a latent image forming unit. The laser writing device 21 includes a laser light source, a scanning rotary polygon mirror, a polygon motor, an fθ lens, and the like. Further, the apparatus main body is provided with a plurality of sheet cassettes 22 for storing sheets S such as transfer paper and OHP film.

  When copying using the apparatus configured as described above, when the user presses the start switch, first, the contents of the document set in the image reading apparatus 200 are read. At the same time, the photosensitive member 10 is rotated by the photosensitive member driving motor, and the surface of the photosensitive member 10 is uniformly charged by the charging device 11 using the charging roller 11a. Next, the writing process is executed using the laser writing device 21 by irradiating the photosensitive member 10 with laser light according to the content of the original read by the image reading device 200. After forming an electrostatic latent image on the surface of the photoconductor 10 in this way, toner is attached to the photoconductor 10 using the developing device 12 to visualize (develop) the electrostatic latent image.

  At the same time as the user presses the start switch, the selected sheet S is sent out from the multi-stage sheet cassette 22 by the calling roller 27. Next, the sheet is separated one by one by the supply roller 28 and the separation roller 29 and sent to the supply path R1. The sheet S sent to the supply path R <b> 1 is conveyed by the sheet conveyance roller 30 and is abutted against the registration roller 23 and stopped. The transfer roller 16 is sent to a transfer nip formed in contact with the photoconductor 10 in accordance with the rotation timing of the toner image that is visualized on the photoconductor 10.

  The toner image on the photoreceptor 10 is transferred to the sheet S fed to the transfer nip by the transfer device 17. The residual toner on the photoconductor 10 after image transfer is removed and cleaned by the cleaning device 14, and the residual potential on the photoconductor 10 from which the residual toner has been removed is removed by the static eliminator. In preparation for the next image formation starting from the charging device 11.

  On the other hand, the sheet S after the image has been transferred is guided to the heat fixing device 24, passed between the heating roller 25 and the pressure roller 26, and conveyed to these rollers while applying heat and pressure to the toner. The image is fixed. Thereafter, the sheet S on which the image has been fixed is discharged onto the discharge stack unit 32 by the discharge roller 31 and stacked.

Next, the configuration and operation of the developing device 12 will be described in more detail.
FIG. 3 is a perspective view showing the appearance of the developing device 12.
FIG. 4 is a perspective view showing a state where the upper casing 1211 and the lower casing 1212 are disassembled so that the inside of the developer accommodating portion of the developing device 12 can be visually recognized.

  As shown in FIG. 4, the developing casing of the developing device 12 is composed of two parts, an upper casing 1211 and a lower casing 1212. A developing roller 12 a is rotatably supported on the upper casing 1211. Further, a developing doctor 12d made of a round bar is fitted into developing doctor holding holes 34a and 34b provided on both side walls of the upper casing 1211. The method for supporting the developing roller 12a and the developing doctor 12d will be described in detail later.

  Further, the lower casing 1212 forms a developer accommodating portion inside the developing device 12. The developer accommodating portion has a partition wall 122 that partitions the first agent accommodating chamber V1 and the second agent accommodating chamber V2. Conveying screws 12b and 12c are provided in the first agent storage chamber V1 and the second agent storage chamber V2, respectively. Each conveying screw 12b, 12c is rotatably supported by the lower casing 1212. The first agent storage chamber V <b> 1 and the second agent storage chamber V <b> 2 communicate with each other through the transfer openings 121 a and 121 b at the end of the partition wall 122.

FIG. 5 is a diagram schematically showing a developer circulation path in the developing device 12. The broken arrow in FIG. 5 indicates the flow of the developer, and the solid arrow in FIG. 5 indicates the flow of the toner replenished from the toner replenishing port 12e.
The developer transported to the downstream end of the second agent storage chamber V2 by the second transport screw 12c passes through the transfer opening 121a at the end of the partition wall 122 and moves to the first agent storage chamber V1. The developer in the first agent storage chamber V1 is transported in the opposite direction to the developer in the second agent storage chamber V2 while being stirred by the first transport screw 12b. And if it reaches the conveyance direction downstream end part of the 1st agent storage chamber V1, it will pass through the delivery opening part 121b of the edge part of the partition wall 122, and will move to the 2nd agent storage chamber V2. As described above, the developer circulates in the developer accommodating portion partitioned by the partition wall 122 by the transport screws 12b and 12c provided in the first agent accommodating chamber V1 and the second agent accommodating chamber V2, respectively.

  A replenishment toner transport path 123 is connected to the upstream end of the developer transport upstream of the first agent storage chamber V1. The replenishing toner transport path 123 is provided with a toner replenishing port 12e, from which new toner and recovered toner collected by the cleaning device 14 are replenished. The first transport screw 12b provided in the first agent storage chamber V1 extends to the replenishment toner transport path 123. The toner replenished from the toner replenishing port 12e is conveyed through the replenishment toner conveyance path 123 by the first conveyance screw 12b, and then passes through the communication hole 123a that communicates the first agent storage chamber V1 and the replenishment toner conveyance path 123. To the first agent storage chamber V1. Further, reference numeral 124 in FIG. 5 denotes a density detection sensor that detects the toner density of the developer, and is installed below the first agent storage chamber V1 of the development casing 121.

FIG. 6 is a schematic sectional view of the developing device 12.
As shown in FIG. 6, the developing roller 12 a includes a developing sleeve and a magnet roller that is a magnetic field generation unit fixedly disposed in the developing sleeve. The magnet roller is a cylindrical member formed by mixing magnetic powder in resin and magnetizing the peripheral surface to form five magnetic poles P1 to P5. The magnetic pole P1 facing the photoconductor 10 is a developing magnetic pole, the transporting magnetic pole P4 is a magnetic transporting magnetic pole that attracts the developer in the second agent storage chamber V2, and the magnetic pole P5 facing the developing doctor 12d is a regulating magnetic pole. Further, the agent separation magnetic pole P2 and the pumping magnetic pole P3 are magnetic poles different from the conveyance magnetic pole 4 and have the same polarity adjacent to each other in the rotation direction of the developing roller 12a, and have a magnetic force for releasing the developer from the developing sleeve. It is a magnetic pole. The angular positions of the magnetic poles P1 to P5 here are the angular positions of the peak of the magnetic flux density in the normal direction. The developer in the agent separation region between the points on the developing roller 12a where the magnetic flux density in the normal direction by the agent separation magnetic pole P2 and the pumping magnetic pole P3 is maximized is detached from the developing sleeve.

  When the developing roller 12a and the conveying screw 12c start to rotate clockwise in the drawing, the developer accumulated around the conveying screw 12c is pushed out in the radial direction of the conveying screw as the conveying screw 12c rotates. . In the present embodiment, the lower part of the conveying screw 12c is surrounded by the inner wall of the lower casing 1212 with an interval of about 1 [mm] from the outer periphery of the conveying screw 12c. For this reason, the developer pushed out by the conveying screw 12c moves along the inner wall of the lower casing 1212 to the upper side of the conveying screw 12c.

  Here, in this embodiment, as shown in FIG. 6, a developer guide member 12g which is a plate-like member is provided. The developer guide member 12g is affixed to the upper casing 1211 and is disposed so as to connect the vicinity of the conveying screw 12c to the developing doctor 12d in a substantially linear shape. Further, one end is in contact with the developing doctor 12d and is bent, and is in contact with the developing doctor 12d without any gap. In the present embodiment, a sheet-like member having a PET material thickness of 0.2 [mm] is used as the developer guide member 12g.

The developer pushed out above the conveying screw 12c is restricted in the moving direction by contacting the inclined surface of the developer guide member 12g. As shown by the arrow in the figure, the developer doctor 12d causes the developer on the developing roller 12a. Head to the developer regulation department. The developer traveling toward the developing roller 12a is captured by the magnetic force between the pumping magnetic pole P4 and the magnetic pole P5 and is carried on the surface of the developing roller 12a.
As described above, the developer moving direction is regulated by the developer guide member 12g, so that the developer can be efficiently supplied to the developing roller 12a. Specifically, in addition to the developer lifted to the vicinity of the developing roller 12a by the blades of the second conveying screw 12c and pumped to the developing roller 12a by the magnetic force of the pumping magnetic pole P4, the developer jumped out of the second conveying screw 12c. Can be carried on the developing roller 12a. Therefore, the developer can be efficiently supplied to the developing roller 12a.

  Further, one end of the developer guide member 12g in the vicinity of the developing doctor 12d is disposed so as to enter a region where the developer can be held by the magnetic force between the magnetic forces P4 and P5 (inside the broken line portion in the figure). Accordingly, it is possible to maintain a state where the developer is densely packed in a space surrounded by the developing roller 12a, the developing doctor 12d, and the developer guide member 12g on the upstream side of the developer restricting portion by the developing doctor 12d. Therefore, the density fluctuation is reduced, which contributes to stabilization of the developer amount after regulation.

  In the present embodiment, as shown in FIG. 6, a round bar member having a circular cross section is used as the developing doctor 12d. By using a round bar member as the developing doctor 12d, it is possible to use a solid bar cut out and subjected to end face processing, and can be constructed at low cost. Furthermore, by using a round bar-shaped doctor member, the component configuration is simple and the cost can be reduced as compared with the SUS plate material.

Next, a method for supporting the developing roller 12a and the developing doctor 12d will be described in detail.
FIG. 7 is a diagram illustrating an example of the developing roller 12a and the developing doctor 12d included in the developing device. The right side in FIG. 7 is the rear side of the copying machine (the back side in FIG. 6), and the left side in FIG. 7 is the front side of the copying machine (the front side in FIG. 6).
As shown in FIG. 7, a cylindrical sleeve flange shaft 12a2 is disposed on the back side of the copying machine of the developing roller 12a. The sleeve flange shaft 12a2 is rotatably held by two roller bearings 31a and 31b. Of these two roller bearings 31a and 31b, the roller bearing 31a located on the axial center side of the developing roller 12a is provided in the casing of the developing device 12. Further, a roller bearing 31b positioned on the outer side in the axial direction of the developing roller 12a is provided on a developing gap face plate described later.

Further, a D-cut magnet shaft 12a1 obtained by cutting a part of a cylindrical member is disposed on the front side of the copying machine of the developing roller 12a. The magnet shaft 12a1 is fixed by a magnet shaft fixing member 32a provided on the upper casing 1211 of the developing device 12 and a magnet shaft fixing member 32b provided on the developing gap face plate, and the sleeve flange shaft 12a2 is fixed at a predetermined angle. doing. Thus, the magnetic pole of the developing roller 12a is held in the developing device 12 so as to be the direction shown in FIG.
Further, the sleeve flange shaft 12a2 and the magnet shaft 12a1 of the developing roller 12a are held by developing gap face plates provided on the front side and the back side of the copying machine, respectively, so that the gap with the photoconductor 10 is set to a predetermined distance. I keep it.

  Both ends of the developing doctor 12d are held by a developing doctor holding hole 34a provided on the front side of the copying machine of the developing device 12 and a developing doctor holding hole 34b provided on the back side of the copying machine. In order to accurately set the gap between the developing roller 12a and the developing doctor 12d, it is desirable that the developing doctor 12d be held in the press-fitting dimension with respect to the two developing doctor holding holes 34a and 34b. For example, if there is a gap between the developing doctor 12d and the two developing doctor holding holes 34a, 34b, the developing doctor 12d may move in the gap, and this causes the developer amount on the developing roller 12a to move. This is because of changes. Thus, the gap between the developing roller 12a and the developing roller 12a can be accurately determined by positioning the both end portions of the developing doctor 12d by the press-fitting dimensions. Furthermore, since the developing doctor 12d can be assembled by press-fitting into the hole of the upper casing, the cost for assembly can be suppressed.

However, if the position of the developing doctor 12d is determined by the press-fitting size, when the developing doctor 12d is attached to the developing device 12, the developing doctor 12d may be bent as follows. That is, when the developing doctor 12d is pushed into the doctor holding holes 34a and 34b, the central portion in the longitudinal direction of the developing doctor 12d is bent due to the force from the upper casing 1211. Then, the amount of developer passing through the central portion in the longitudinal direction of the developing doctor 12d may increase or decrease due to the amount of bending.
Further, when supplying the developer to the photosensitive member 10, the developer amount on the developing roller is regulated by the developing doctor 12d. At this time, the developing doctor 12d reacts with the developer passing between the developing doctor 12d and the developing roller. The force in the direction of arrow A in FIG. Due to this force, the central portion in the longitudinal direction of the developing doctor may bend and the gap between the developing roller and the developing doctor at the central portion in the longitudinal direction of the developing roller may be widened.

A change in the gap between the developing roller 12a and the developing doctor 12d at the center in the longitudinal direction of the developing roller 12a due to the bending of the developing doctor 12d will be described.
FIG. 8 is an explanatory diagram showing an example of a developing doctor. FIG. 9 is a diagram illustrating another bending state of the developing doctor. FIG. 10 is a view showing still another bending state of the developing doctor.
The developing doctor 12d shown in FIG. 8 is such that when the developing doctor 12d is assembled to the developing device 12, the central portion in the longitudinal direction of the developing doctor 12d protrudes in a direction away from the developing roller 12a as compared to both ends in the longitudinal direction. It has a bent shape. As described above, when the gap between the developing roller 12a and the developing doctor 12d at the center in the longitudinal direction of the developing roller 12a is widened due to the bending when the developing doctor 12d is attached to the developing device 12, the developing is performed as follows. The doctor 12d bends. That is, when supplying the developer to the developing roller 12a, the developer doctor 12d is further bent as shown in FIG. 9 by the pressure of the developer passing between the developing roller 12a and the developing doctor 12d. As a result, the deviation of the developer amount in the longitudinal direction of the developing roller 12a increases, and the deviation of the developer amount on the developing roller 12a occurs in the longitudinal direction of the developing roller 12a.

  In the developing doctor 12d shown in FIG. 10, when the developing doctor 12d is assembled to the developing device 12, the central portion in the longitudinal direction of the developing doctor 12d is convex toward the developing roller 12a as compared with the both ends in the longitudinal direction. It has a bent shape. As described above, when the gap between the developing roller 12a and the developing doctor 12d in the central portion in the longitudinal direction of the developing roller 12a is narrowed due to bending when the developing doctor 12d is attached to the developing device 12, the developing roller 12a and the developing roller 12a are developed. The deflection of the developing doctor is offset by the pressure of the developer passing between the doctors 12d. That is, the central portion of the developing doctor 12d in the longitudinal direction is pushed away from the developing roller 12a by the developer pressure, thereby eliminating the bending of the developing doctor 12d. Thereby, the gap between the developing roller 12a and the developing doctor 12d when supplying the developer to the developing roller 12a can be made uniform in the longitudinal direction, and a uniform pumping amount can be obtained over the longitudinal direction of the developing roller 12a. .

  However, in the conventional developing device, when the developing doctor is attached to the developing device, it cannot be predicted in which direction the developing doctor bends, and it is difficult to stably create the state of FIG.

FIG. 11 is a view showing an example of an end portion of the developing doctor 12d.
In the developing doctor 12d of this embodiment, both end portions of the developing doctor 12d have an appropriate press-fitting dimension that allows rotation within the two developing doctor holding holes 34a and 34b provided in the upper casing 1211. As shown in FIG. 11, substantially rectangular grooves 35 are formed on the end faces of both end portions of the developing doctor 12d as engaging portions that engage with members that apply rotational torque to the developing doctor 12d from the outside. The developing doctor 12d can be rotated by fitting the tip of a jig such as a minus driver into the groove 35. Thereby, after assembling the developing doctor 12d to the developing device, the bending direction of the developing doctor 12d can be measured, and the developing doctor can be rotated so that the bending becomes convex toward the developing roller.
In this embodiment, the bending direction of the developing doctor 12d is measured by inserting a gap gauge having a plate-like thickness between the developing doctor 12d and the developing roller 12a.

  Thus, by making the developing doctor rotatable about the axis, the developing doctor can be brought into the state shown in FIG. Thereby, the gap between the developing roller and the developing doctor when the developer is supplied to the developing roller can be made uniform in the longitudinal direction. Accordingly, since a uniform pumping amount can be obtained over the developing roller longitudinal direction, it is possible to suppress the occurrence of density unevenness of the image caused by the deviation of the developer amount in the developer carrying member longitudinal direction.

In the above description, the configuration in which the grooves 35 are provided at both ends of the developing doctor 12d has been described, but a configuration in which only one end is provided may be employed.
Further, in the above description, the configuration in which the substantially rectangular groove 35 is formed on the end surface as the engaging portion that engages with the member that gives rotational torque to the developing doctor from the outside has been described. Not exclusively. For example, a configuration in which a cross-shaped groove that engages the tip of a plus driver is formed, or a configuration in which a flat surface is formed on at least a part of the end surface of the developing doctor so that the end of the developing doctor is sandwiched by a jig. It is good.

What was demonstrated above is an example, and there exists an effect peculiar for every following aspect.
(Aspect A)
A predetermined gap is provided between the developer carrier and a developer carrier such as a developing roller 12a that carries the developer on the surface and supplies the developer to an image carrier such as the photoconductor 10 disposed opposite to the surface. In the developing device such as the developing device 12, the developer including a developer regulating member such as a cylindrical developing doctor 12 d that is disposed so as to be opposed to each other and regulates the amount of developer carried on the developer carrying member. The restriction member is rotatable about the axis.

Conventionally, a cylindrical round bar doctor used as a developer regulating member has a lower strength than a plate-like doctor, and therefore, a bending phenomenon is likely to occur. For example, in the developing device of Patent Document 1, when the developer carried on the developing roll passes between the developer carrying body and the developer regulating member, the developer carrying body and the developer regulating member A force that pushes the gap is applied to the round bar doctor. Due to this force, the round bar doctor may be deformed and bent so as to protrude in a direction away from the developing roll. If the end of the round bar doctor is fixed to the developing device with a press-fitting dimension, when the round bar doctor is attached to the main unit, the round bar doctor is pushed into the holding part such as a casing, There is a possibility that the central portion in the longitudinal direction is bent.
If the gap between the developer carrier and the round bar doctor is widened due to the bending of the round bar doctor, the developer amount on the developing roller will vary in the longitudinal direction of the developer carrier, resulting in uneven density of the image. Resulting in. In the conventional developing device, when the developing doctor is attached to the developing device, it is impossible to predict which direction the developing doctor will bend, and uneven image density caused by the deviation of the developer amount in the longitudinal direction of the developer carrier occurs. It was.

  In this aspect, since the developer regulating member is rotatable about the axis, it is possible to confirm the direction of deflection of the developer regulating member and to direct the convex direction of the deflection of the developer regulating member toward the developer carrying member. Become. When the convex direction of the deflection of the developer regulating member is directed to the developer carrying member, the developer carrying member is offset by the pressure of the developer passing between the developer carrying member and the development regulating member. And the gap between the development regulating members can be made uniform. Accordingly, it is possible to suppress the occurrence of image density unevenness caused by the deviation of the developer amount in the longitudinal direction of the developer carrier.

(Aspect B)
In the developing device of Aspect A, an engaging portion that engages with a member that applies rotational torque from the outside to the developer regulating member is formed at at least one end in the longitudinal direction of the developer regulating member such as the developing doctor 12d. It is characterized by that.
In this aspect, at least one end of the developer regulating member in the longitudinal direction is formed with an engaging portion that engages with a member for applying a rotational torque to the developer regulating member from the outside. The regulating member can be rotated around the axis.

(Aspect C)
In the developing device of aspect B, a groove such as the groove 35 as the engaging portion is formed on an end surface of at least one end portion of the developer regulating member such as the developing doctor 12d in the longitudinal direction.
In this aspect, since the groove as the engaging portion is provided on the end surface of the developer regulating member, a part of the jig for rotating the developer carrying member can be engaged with the groove. The agent carrier can be rotated.

(Aspect D)
In the developing device according to aspect B or C, at least one end in the longitudinal direction of the developer regulating member such as the developing doctor 12d is exposed from the main body of the device.
In this aspect, since at least one end portion of the developer regulating member in the longitudinal direction is exposed from the apparatus main body, workability when the developer regulating member is rotated by a jig or the like is improved.

(Aspect E)
In the developing device according to any one of the aspects A to D, both ends of the developer regulating member are held in the apparatus main body by press-fitting.
In this aspect, as described in the above embodiment, the gap between the developer carrier and the developer regulating member can be accurately determined. Furthermore, the cost concerning assembly can be suppressed.

(Aspect F)
In the developing device according to any one of Embodiments A to E, the developer regulating member is a metal material.

(Aspect G)
At least an image carrier such as the photoconductor 10 and a developing device such as a developing device 12 that supplies a developer to the latent image formed on the surface of the image carrier and develops it, and is detachable from the apparatus main body. In a process cartridge such as the possible process cartridge 1, the developing device according to any one of the aspects A to F is used as the developing device.
In this aspect, it is possible to obtain a process cartridge that suppresses the occurrence of uneven density in the image caused by the deviation of the developer amount in the longitudinal direction of the developer carrier. The positional accuracy between the members can be maintained with high accuracy, and the quality of the formed image can be improved.

(Aspect H)
An image forming apparatus comprising: an image carrier such as a photoreceptor 10; and a developing device such as a developing device 12 that supplies a developer to a latent image formed on the surface of the image carrier and develops the developer. As the apparatus, the developing apparatus according to any one of aspects A to G is used.
In this aspect, as described in the above embodiment, it is possible to obtain an image forming apparatus that suppresses occurrence of density unevenness of an image caused by a deviation in the developer amount in the longitudinal direction of the developer carrier.

(Aspect I)
An image carrier such as the photoconductor 10 and a developing device such as a developing device 12 that supplies a developer to the latent image formed on the surface of the image carrier and develops it, and is detachable from the apparatus main body. An image forming apparatus including a process cartridge such as the process cartridge 1 includes the process cartridge according to aspect H as the process cartridge.
In this aspect, as described in the above-described embodiment, the image carrier and the developing device are unitized as a process cartridge, thereby facilitating replacement and maintenance work.

DESCRIPTION OF SYMBOLS 1 Process cartridge 10 Photoconductor 11 Charging device 12 Developing device 12a Developing roller 12a1 Magnet shaft 12a2 Sleeve flange shaft 12b, 12c Each conveyance screw 12d Developing doctor 12e Toner replenishing port 12g Developer guide member 14 Cleaning device 17 Transfer device 20 Toner bottle 21 Laser writing device 24 Thermal fixing device 31a, 31b Roller bearing 32a, 32b Magnet shaft fixing member 34a, 34b Developing doctor holding hole 35 Groove 121 Developing casing 500 Copying machine 1211 Upper casing 1212 Lower casing

JP 2012-203252 A

Claims (9)

  A developer is carried on the surface, and the developer carrying member that supplies the developer to the image carrying member arranged opposite to the developer carrying member, and the developer carrying member are arranged to face each other with a predetermined gap therebetween. A developing device comprising a cylindrical developer regulating member for regulating the amount of developer carried on a carrier, wherein the developer regulating member is rotatable about an axis.   2. The developing device according to claim 1, wherein an engaging portion that engages with a member for applying a rotational torque from the outside to the developer regulating member is formed at at least one end in the longitudinal direction of the developer regulating member. A developing device.   3. The developing device according to claim 2, wherein a groove as the engaging portion is formed on an end surface of at least one end portion in the longitudinal direction of the developer regulating member.   4. The developing device according to claim 2, wherein at least one end portion of the developer regulating member in the longitudinal direction is exposed from the apparatus main body.   5. The developing device according to claim 1, wherein both ends of the developer regulating member are held in the apparatus main body by press-fitting.   The developing device according to claim 1, wherein the developer regulating member is a metal material.   In a process cartridge detachable from the apparatus main body, the developing apparatus includes at least an image carrier and a developing device that supplies a developer to the latent image formed on the surface of the image carrier and develops the latent image. A process cartridge using the developing device according to any one of claims 1 to 5.   6. An image forming apparatus comprising an image carrier and a developing device that supplies a developer to a latent image formed on a surface of the image carrier and develops the image carrier. An image forming apparatus using the developing device according to claim 1.   In an image forming apparatus comprising: an image carrier; and a developing device that supplies a developer to the latent image formed on the surface of the image carrier and develops the latent image. An image forming apparatus comprising the process cartridge according to claim 8 as the process cartridge.

Images