JP2003186286A - Developing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device that has an electrode member which applies a development bias to a sleeve original tube without moving the sleeve original tube away from its center (without eccentricity). <P>SOLUTION: A contact linear spring 110 formed by bending a flexible spring material or the like which has a circular cross-section is inserted into a sleeve original tube 82 and is also fixed to a fixing shaft 88. The contact linear spring 110 is in contact with the internal face of the sleeve original tube 82, specifically with four contact faces 131, 132, 133, and 134. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device that supplies a developer to an electrostatic latent image to form a developed image.

[0002]

2. Description of the Related Art As an output device of a computer or a workstation, an electrophotographic image forming apparatus for forming an image on a recording medium using a powdery developer (toner) is known. The image forming apparatus includes a photosensitive drum on which an electrostatic latent image is formed, a developing device for supplying a developer to the electrostatic latent image formed on the photosensitive drum, and the like. Among various image forming apparatuses, there is one in which a process cartridge in which a photosensitive drum, a developing device and the like are integrally incorporated is mounted. The process cartridge and the developing device incorporated in the process cartridge will be described with reference to FIGS. 6 and 7.

FIG. 6 is a schematic view showing a schematic structure of a process cartridge. FIG. 7 is a front view schematically showing the developing sleeve as seen from a direction orthogonal to the longitudinal direction thereof, and the central portion in the longitudinal direction is omitted.

The process cartridge 10 incorporates a photosensitive drum 12 on which an electrostatic latent image is formed, a developing device 20 for developing the electrostatic latent image formed on the photosensitive drum 12, and the like. The process cartridge 10 includes a charger 14 for uniformly charging the surface layer of the photosensitive drum 12,
The developer remaining on the photosensitive drum 12 after the transfer is transferred to the blade 1
A cleaning device 16 for scraping and cleaning with 6a is also incorporated.

The developing device 20 includes the photosensitive drum 12 described above.
It is located near. The developing device 20 includes a developer 22.
And a developer accommodating chamber 30 for accommodating the developer
The developer 22 contained in the developing unit 40 is roughly divided into the developing unit 40 and the developing unit 40.

The developer accommodating chamber 30 is provided with a stirring member 32 which rotates in the direction of arrow A about a rotation shaft 32a. By rotating the stirring member 32 in the direction of arrow A, the developer 22 stored in the developer storage chamber 30
Is conveyed to the developing section 40 while being stirred.

The developing section 40 is provided with a stirring member 42 that conveys the developer sent from the developer accommodating chamber 30 toward the photosensitive drum 12 while stirring the same. The stirring member 42 is a rotary shaft 42a. The developer is conveyed while being agitated by rotating in the direction of the arrow B with respect to. The developer is charged by being conveyed or stirred in this way.

The developer carried to the stirring member 42 is sent to a cylindrical developing sleeve 50 which rotates in the direction of arrow C. The developing sleeve 50 is a cylindrical sleeve tube 52.
Alternatively, it is composed of a cylindrical magnet roller 54 and the like which is coaxially fixed therein. Magnet roller 5
4 is four magnetic poles S1 and N having alternately opposite magnetism.
1, S2, N2. The sleeve tube 52 rotates in the direction of arrow C, but the magnet roller 54 is fixed and does not rotate.

The developer carried by the stirring member 42 is charged. The charged developer is adsorbed and restrained on the outer peripheral surface of the sleeve tube 52 by the magnetic force of the magnetic pole S2 (take-in pole), and is conveyed to the magnetic pole N1 (cut pole) as the sleeve tube 52 rotates. A doctor blade 56 for fixing the thickness of the developer to a constant value is fixed in the vicinity of the portion of the cut pole N1 on the downstream side in the rotational direction of the sleeve tube 52. By this doctor blade 56, the thickness of the developer conveyed while being adsorbed on the surface of the sleeve tube 52 becomes constant. The developer having a constant thickness is supplied to the magnetic pole S as the sleeve tube 52 rotates.
1 is the developing pole and is the main magnetic pole. The photosensitive drum 12 is arranged so as to face a downstream side portion of the magnetic pole S1 in the rotational direction of the sleeve tube 52. The area sandwiched between the magnetic pole S1 and the photosensitive drum 12 is a developing area where the electrostatic latent image is developed.

A developing bias (bias voltage) in which direct current and alternating current are superposed is applied to the sleeve tube 52 by a bias power source (not shown). This developing bias causes the developer adsorbed to the portion of the sleeve tube 52 corresponding to the magnetic pole S1 to fly toward the electrostatic latent image on the photosensitive drum 12, thereby developing and developing the electrostatic latent image. An image is formed.

The detailed structure of the developing sleeve 50 will be described.

The developing sleeve 50, as shown in FIG.
The sleeve tube 52 is made of a conductive material such as aluminum, and the cylindrical magnet roller 54 is coaxially fixed inside the sleeve tube 52. A fixed shaft 58 serving as a rotation center axis of the sleeve tube 52 is fixed inside the sleeve tube 52. This fixed shaft 5
8 is formed integrally with the magnet roller 54.

Both longitudinal ends of the fixed shaft 58 are fixed to the side wall 24 of the developing device 20. The sleeve element pipe 52 is shorter than the fixed shaft 58, and both longitudinal end portions of the fixed shaft 58 protrude from the longitudinal end portions of the sleeve element pipe 52. The magnet roller 54 is shorter than the sleeve tube 52, and the entire magnet roller 54 is housed in the internal space of the sleeve tube 52.

Flanges 60 and 62 are integrally fixed to the fixed shaft 58 at both longitudinal ends of the sleeve blank 52. These flanges 60 and 62 are shaped so as to be located outside both ends in the longitudinal direction of the sleeve tube 52. Further, the portions of the flanges 60 and 62 outside the longitudinal ends of the sleeve element pipe 52 are the bearings 6.
It is rotatably supported by 4, 64.

Ring-shaped spacer rollers 66 and 68 are fitted in the flanges 60 and 62. The spacer rollers 66 and 68 are coaxial with the sleeve tube 52 and rotate about the fixed shaft 58 as a rotation center. The outer diameters of the spacer rollers 66 and 68 are larger than the outer diameter of the sleeve tube 52. Further, the spacer rollers 66 and 68 are pressed so as to come into contact with the photosensitive drum 12. Therefore, the sleeve tube 52 and the photosensitive drum 12 always maintain a constant distance.

A sleeve gear 70 is fixed to a portion of the flange 62 outside the bearing 64. The sleeve gear 70 meshes with the drum gear 18 that rotates the photosensitive drum 12. Therefore, the flange 62 and the sleeve tube 52 rotate in synchronization with the photosensitive drum 12.

An elastic electrode 72 for applying a developing bias to the sleeve tube 52 is arranged around a portion of the fixed shaft 58 outside the spacer roller 68. The elastic electrode 72 is elastically deformable, and the one end 7
2a is in elastic contact with the fixed electrode 74. Further, the elastic electrode 72 extends from the one end portion 72a thereof and extends to the flange 62.
And the other end portion (not shown) is in electrical contact with the inner peripheral surface of the sleeve element pipe 52. The fixed electrode 74 described above is a bias power source (not shown).
The developing bias from the bias power source is connected to the sleeve tube 5 via the fixed electrode 74 and the elastic electrode 72.
2 will be conducted.

[0018]

As described above, the other end of the elastic electrode 72 is in electrical contact with the inner peripheral surface of the sleeve tube 52. In this case, in order to electrically and surely contact the other end of the elastic electrode 72 and the inner peripheral surface of the sleeve raw pipe 52, the other end of the elastic electrode 72 causes the sleeve raw pipe 52
The inner peripheral surface of is pressed from the inside. Therefore, the pressed portion and the peripheral portion of the sleeve element pipe 52 may be slightly eccentric (sway) when the sleeve element pipe 52 rotates.

In the case of such eccentricity, the pressure at which the doctor blade 56 comes into contact with the sleeve element pipe 52 changes with the rotation of the sleeve element pipe 52, and the sleeve element pipe 5
In the longitudinal direction of No. 2, the thickness of the developer is not uniform and is different. Further, this eccentricity also causes the spacer rollers 66 and 68 to swing, so that the distance between the sleeve element tube 52 and the photosensitive drum 12 changes as the sleeve element tube 52 rotates.

Due to the above-mentioned fluctuations, the density of the developed image obtained by developing the electrostatic latent image is uneven, or the line width is uneven when the developed image is linear. To do. As a result, similar density unevenness and line width unevenness occur in the image formed on the recording medium, and the image deteriorates.

In view of the above circumstances, it is an object of the present invention to provide a developing device provided with an electrode member for applying a developing bias to the sleeve tube without eccentricity (without offsetting). To do.

[0022]

SUMMARY OF THE INVENTION To achieve the above object, a developing device of the present invention comprises a fixed shaft fixed to a predetermined frame and to which a developing bias is applied, with the fixed shaft as the center of rotation. A rotating cylindrical sleeve tube, and a cylindrical magnet roller having magnetism which is fixed inside the sleeve tube so as to be coaxial with the sleeve tube, and a developing bias is applied to the fixed shaft to provide the sleeve. In a developing device that supplies the developer to the electrostatic latent image by adhering the developer to the outer peripheral surface of the raw tube to develop the electrostatic latent image,
(1) An electrode member slidably attached to the fixed shaft is provided, which is in pressure contact with the inner peripheral surface of the sleeve tube and has a reaction force of the pressure contact in a direction orthogonal to the fixed shaft. It is a feature.

Here, (2) the electrode member may elastically press the inner peripheral surface of the sleeve tube.

(3) The electrode member may be disposed inside the sleeve tube.

Furthermore, (4) the electrode member may press a plurality of locations on the inner peripheral surface of the sleeve element tube, and counteract the reaction forces at these locations.

Still further, (5) the electrode member may slide on the outer peripheral surface of the fixed shaft in accordance with the rotation of the sleeve tube and rotate together with the sleeve tube.

Further, in the developing device, (6) conductive grease may be applied to a sliding surface on which the electrode member slides on the outer peripheral surface of the fixed shaft.

Furthermore, (7) the sleeve tube is
A recess may be formed on the inner peripheral surface of the electrode member. (8) One end of the electrode member may be fitted in and in contact with the recess.

Further, the developing device (9) has the fixed shaft having one end portion fitted in each longitudinal end portion of the sleeve element tube and having the other end portion protruding from each longitudinal end portion. It may be provided with a pair of flanges that rotate about the rotation center, and (10) a pair of bearings that rotatably hold one end and the other end of each of the pair of flanges.

Furthermore, (11) the pair of flanges may be made of synthetic resin.

Furthermore, the developing device is (12) rotated around the fixed shaft, which is fixed to the other end of each of the pair of flanges and has an outer diameter larger than that of the leave tube. A pair of rollers may be provided.

Furthermore, (13) the fixed shaft may be formed with a groove into which the electrode member is fitted.

Furthermore, (14) the fixed shaft and the magnet roller may be integrally formed.

Furthermore, the developing device comprises (15) a positioning member that supports one end of the fixed shaft and determines the position of the one end in the longitudinal direction of the fixed shaft;
A biasing means may be provided for biasing the fixed shaft in the longitudinal direction so that the one end is located at a position determined by the positioning member.

Furthermore, the developing device may be (17) incorporated in a process cartridge incorporating an image bearing member on which an electrostatic latent image is formed.

[0036]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a developing device of the present invention will be described below with reference to the drawings.

The developing device of the present invention includes a process cartridge 10 (see FIG. 6) in which a photosensitive drum 12 (an example of an image carrier according to the present invention, see FIG. 6) on which an electrostatic latent image is formed is incorporated. ) Is incorporated into. The developing device of the present invention has many structures common to the developing device 20 shown in FIG. However, as will be described later, the structure of the developing sleeve 80 is different from that of the developing sleeve 50 of the developing device 20.
Therefore, here, the developing sleeve 80 of the developing device 200 of the present invention will be described.

With reference to FIG. 1, the developing sleeve of the developing device of the present invention will be described.

FIG. 1 is a front view schematically showing the developing sleeve as seen from a direction orthogonal to its longitudinal direction, and the central portion in the longitudinal direction is omitted.

The developing sleeve 80 is composed of a cylindrical sleeve tube 82, a cylindrical magnet roller 84 (having the same structure as the magnet roller 54) coaxially fixed therein. The sleeve tube 82 is made of a conductive material such as aluminum. A fixed shaft 88 serving as a rotation center axis of the sleeve tube 82 is fixed inside the sleeve tube 82.
The fixed shaft 88 is formed integrally with the magnet roller 84.

Both longitudinal ends of the fixed shaft 88 are fixed to the side walls 202 and 204 of the developing device 200. Side wall 2
A recess 202a (which is an example of a positioning member according to the invention) is formed in 02, and one end of the fixed shaft 88 in the longitudinal direction abuts against the bottom of the recess 202a and is supported thereby. As a result, the position of one end of the fixed shaft 88 in the longitudinal direction is determined. One end in the longitudinal direction of the fixed shaft 88 has a D-cut shape, and a coil spring (an example of the urging means referred to in the present invention, which is an example of the urging means in the present invention, is shown in FIG. Energized (pressed) by (not shown). Therefore, the fixed shaft 88
Will always be in the regular position.

The sleeve tube 82 is shorter than the fixed shaft 88, and both ends of the fixed shaft 88 in the longitudinal direction are the sleeve tube 8.
2 protrudes from both ends in the longitudinal direction. The magnet roller 84 is shorter than the sleeve tube 82, and the entire magnet roller 84 is housed in the internal space of the sleeve tube 82.

Flanges 90 and 92 are fitted respectively at both longitudinal ends of the sleeve tube 82. These flanges 90 and 92 are made of synthetic resin and have a shape such that they are located outside both ends in the longitudinal direction of the sleeve tube 82. Further, the portions of the flanges 90 and 92 outside the longitudinal ends of the sleeve tube 82 are the bearings 9.
It is rotatably supported by 4, 96. Fixed shaft 8
8 does not rotate, but the flanges 90 and 92 are configured to rotate together with the sleeve tube 82.

Ring-shaped spacer rollers 98 and 100 are fitted into the flanges 90 and 92. The spacer rollers 98 and 100 are coaxial with the sleeve tube 82 and rotate about the fixed shaft 88 as a rotation center. The outer diameters of the spacer rollers 98 and 100 are larger than the outer diameter of the sleeve tube 82. This difference in outer diameter is a difference that allows the sleeve tube 82 and the photosensitive drum (not shown) to maintain a predetermined distance. The spacer rollers 98 and 100 are pressed against the photosensitive drum (not shown). Therefore, the sleeve tube 82 and the photosensitive drum are always kept at a constant distance.

A sleeve gear 102 is fixed to a portion of the flange 92 outside the bearing 96. The sleeve gear 102 meshes with a drum gear (not shown) that rotates the photosensitive drum. Therefore, the flanges 90 and 92 and the sleeve element tube 82 rotate in synchronization with the photosensitive drum.

A groove (not shown) is formed in a portion of the fixed shaft 88 between the magnet roller 84 and the flange 90. A contact wire spring 110 (which is an example of an electrode member according to the present invention) is fitted in this groove. Therefore, the contact wire spring 110 cannot be moved carelessly in the longitudinal direction of the fixed shaft 88. Further, since the fixed shaft 88 does not rotate, the contact wire spring 110 is rotated with the rotation of the sleeve tube 82.
Rotates while sliding on the inner surface of the groove. Conductive grease is applied to the inner surface of the groove (which is an example of the sliding surface in the present invention). Therefore, the inner surface of the groove and the contact wire spring 110
Is hard to wear.

The contact wire spring 110 is disposed inside the sleeve tube 82, and is in electrical contact with the inner peripheral surface of the sleeve tube 82. Further, the fixed shaft 88 is connected to a bias power supply. Therefore, the developing bias is applied to the sleeve tube 82 via the fixed shaft 88 and the contact wire spring 110. Since the contact point spring 110 is arranged inside the sleeve element tube 82, dust or the like is unlikely to adhere to the portion where the sleeve element tube 82 and the contact point spring 110 electrically contact each other. Further, the groove of the fixed shaft 88 is also formed inside the sleeve tube 82, and dust and the like are unlikely to adhere to this groove.
Therefore, it is possible to prevent electrical instability due to dust or the like attached to such an electrical contact portion.

Referring to FIGS. 2 and 3, contact wire spring 110
Will be described.

FIG. 2 is a front view schematically showing the elasticity of the contact wire spring. FIG. 3 is a front view showing a contact wire spring fixed to the sleeve tube.

The contact wire spring 110 is formed by bending a flexible spring material having a circular cross section. The contact point spring 110 is fixed to the fixed shaft 88 by the fixed portion 11.
2 and a pair of contact portions 114 for contacting the sleeve tube 82.

The fixing portion 112 has a U-shape. The bottom 112 a (located above in FIG. 2) of the fixed portion 112 does not come into contact with the sleeve tube 82. The U-shaped central portion 112b is curved outward. The central portion 112b is fitted into the groove of the fixed shaft 88. U-shaped tip 112c
Extends outside. The tip portion 112c bends when the contact wire spring 110 is press-fitted (pressed) into the sleeve element pipe 82 as shown by a dotted line. A contact portion 114 extends from each of the two tip portions 112c.

The shape of the pair of contact portions 114 is L-shaped. Border portion 114a between the contact portion 114 and the fixed portion 112
Contacts the inner peripheral surface 82a of the sleeve tube 82. Also,
The L-shaped bent portion 114b is also the inner peripheral surface 82 of the sleeve tube 82.
To contact.

No external force acts (sleeve tube 82
The contact wire spring 110 (which is not press-fitted in) is provided with a pair of tip portions 112c and a pair of contact portions 1 as shown by the solid line in FIG.
14 has spread. In this state, the diameter of the circle 120 drawn by the outer surface of the bent portion 114b is about 0.5 mm to 1.5 mm larger than the inner diameter of the sleeve tube 82. Similarly, the diameter of the circle 122 drawn by the outer surface of the boundary portion 114a is larger than the inner diameter of the sleeve tube 82 by about 0.5 mm to 1.5 mm. However, the outer diameter of the circle 120 is larger than the outer diameter of the circle 122.

By pressing the contact wire spring 110 into the sleeve element tube 82 and fitting it into the groove of the fixed shaft 88, the contact wire spring 110 is bent and deformed as shown by the broken line in FIG. In this case, the contact wire spring 110 has four contact surfaces 13
1,132,133,134 contact the inner peripheral surface of the sleeve tube 82. Four contact surfaces 131, 132, 133
134 is elastically pressed (pressed) to the inner peripheral surface 82a of the sleeve tube 82 by the elastic force of the contact wire spring 110, and receives a reaction force from the inner peripheral surface 82a. The direction of this reaction force is a direction orthogonal to the fixed shaft 88. Therefore, the contact wire spring 110 and the sleeve tube 82
The contact pressure with is sufficiently high.

The reaction force on the two contact surfaces 131 and 133 acts in the direction in which the straight line 140 in FIG. 2 extends.
Therefore, the reaction forces on the two contact surfaces 131 and 133 cancel each other out. Similarly, the reaction force on the two contact surfaces 132 and 134 acts in the direction in which the straight line 142 in FIG. 2 extends. Therefore, the reaction forces on the two contact surfaces 132 and 134 cancel each other out. That is, the four contact surfaces 131, 13
The contact wire springs 110 are arranged so that the sum vectors of the reaction forces at 2, 133 and 134 cancel each other out.
Is pressed against. Therefore, the sleeve element tube 82 is not biased by the contact for applying the developing bias to the sleeve element tube 82. Further, since this contact point is multipoint, the developing bias can be stably applied to the sleeve tube 82.

Consider a case where the sleeve element pipe 82 rotates while the contact wire spring 110 is pressed into the sleeve element pipe 82 (the state shown in FIG. 3).

At one contact surface (for example, contact surface 131), the contact wire spring 110 has the inner peripheral surface 82 of the sleeve tube 82.
When the force F1 for pressing a is compared with the force F2 for the curved portion 112b to press the fixed shaft 88 by the reaction force of this force F1, there is a change in the bending force of the contact point spring 110, so F1> F2 … (1).

Here, from the center of the fixed shaft 88 to the contact surface 13
The distance to 1 is X1, the distance from the center of the fixed shaft 88 to the curved portion 112b is X2, and the rotational speed of the sleeve tube 82 is r. Further, the peripheral speed (rotational speed of the contact surface 131) at the position where the contact wire spring 110 and the inner peripheral surface 82a of the sleeve element tube 82 contact each other is set to V1, and the contact wire spring 1
The peripheral speed at the position where 10 and the fixed shaft 88 contact is V
Set to 2. In this case, V1 = 2π · X1 / r, V2 =
2π · X2 / r and X1> X2, so V1> V2 (2).

The frictional force at the above-mentioned two contact positions will be examined.

Assuming that the frictional resistances at the above-mentioned two contact positions are substantially equal, one contact surface (for example, contact surface 13)
When the frictional force between the contact wire spring 110 and the inner peripheral surface 82a of the sleeve tube 82 in 1) is F1 ′ and the frictional force between the curved portion 112b and the fixed shaft 88 is F2 ′, F1 is calculated from the equation (1). '>F2' (3).

At one contact surface (for example, contact surface 131), the contact wire spring 110 has the inner peripheral surface 82 of the sleeve tube 82.
When the work amount required to move the position where a is pressed is W1 and the work amount required to move the position where the curved portion 112b presses the fixed shaft 88 is W2,
W1 = F1 ′ · V1, W2 = F2 ′ · V2,
From the expressions (2) and (3), W1 >> W2 (4)

When the sleeve tube 82 rotates,
According to the equation (4), sliding the fixed shaft 88 and the contact wire spring 110 requires less energy than sliding on the contact surfaces 131, 132, 133 and 134. Therefore, when the sleeve tube 82 rotates, the fixed shaft 88 and the contact wire spring 1
10 slides, but contact surfaces 131, 132, 133, 1
It does not slide at 34. Therefore, the sleeve tube 82
Is formed of a material such as an aluminum alloy that is easily worn, the contact wire spring 110 causes the sleeve tube 8
2 is never scraped. Further, since the contact wire spring 110 contacts the inner peripheral surface of the sleeve tube 82, the contact surface 13
Dust is unlikely to adhere to 1,132,133,134.
Therefore, it is possible to suppress the generation of electric noise due to the adhesion of dust.

Another example of the sleeve tube and the contact wire spring will be described with reference to FIGS. 4 and 5.

FIG. 4 is a front view schematically showing the developing sleeve of the modification as seen from the direction orthogonal to the longitudinal direction thereof, and the central portion in the longitudinal direction is omitted. FIG. 5 is a front view showing the contact wire spring fixed to the sleeve tube.
In these figures, the same components as those shown in FIG. 1 are designated by the same reference numerals.

The feature of the modified example is that a concave portion is formed on the inner peripheral surface of the sleeve element tube 182, and the end portion of the contact wire spring 150 is fitted and brought into contact with the concave portion. Two concave portions 182a are formed on the inner peripheral surface of the sleeve element pipe 182. The contact wire spring 15 is provided in each of the two recesses 182a.
The end of 0 fits in and is in contact.

The contact wire spring 150 is formed by bending a flexible spring material having a circular cross section. The contact point spring 150 is fixed to the fixed shaft 88 by the fixed portion 15.
2 and a pair of contact portions 154 for contacting the sleeve element tube 182.

The fixing portion 152 has a U-shape. The bottom portion 152a of the fixing portion 152 (located above in FIG. 5) does not come into contact with the sleeve raw tube 182. The U-shaped central portion 152b is curved outward. This central portion 152b
Is fitted into the groove of the fixed shaft 88. U-shaped tip 152
c extends outward. When the contact wire spring 150 is press-fitted (pressed) into the sleeve element pipe 182, the tip end portion 152c bends as shown in FIG. A contact portion 154 continuously extends from each of the two tip portions 152c.

The pair of contact portions 154 are curved curved portions 15
4a and a linear portion 154b linearly extending further outward from the tip of the curved portion 154a. This straight part 1
The tip portion of 54b is fitted in the recess 182a.

No external force is applied (sleeve tube 82
The contact wire spring 150 (which is not press-fitted in) is expanded a little further outward than that shown in FIG. Contact wire spring 15
By pressing 0 into the sleeve element tube 182 and fitting it into the groove of the fixed shaft 88, the contact wire spring 110 is bent and deformed so as to be contracted. In this case, the tip portion of the linear portion 154b is fitted in the recess 182a. Therefore,
The tip portion (contact point of the developing bias) of the linear portion 154b fitted in the concave portion 182a does not slide on the inner peripheral surface of the sleeve tube 182. Also, from the viewpoint of the above-mentioned workloads W1 and W2, the tip portion of the straight line portion 154b has the sleeve tube 182.
The fixed shaft 88 and the contact wire spring 150 slide without sliding on the inner peripheral surface of the. Therefore, even if the sleeve element pipe 182 is formed of a material such as aluminum alloy that is easily worn, the contact element spring 150 does not scrape the sleeve element pipe 182. The contact wire spring 150 is the sleeve tube 1.
Since it contacts the inner peripheral surface of 82, it is difficult for dust and the like to adhere to the tip portion (contact point of the developing bias) of the linear portion 154b. Therefore, it is possible to suppress the generation of electric noise due to the adhesion of dust.

[0070]

As described above, in the developing device of the present invention, the electrode member press-contacts the inner peripheral surface of the sleeve tube, and the reaction force of this press-contact is directed in the direction orthogonal to the fixed axis. A portion of the raw tube near the electrode member in pressure contact rotates without eccentricity. Therefore, the distance between the outer peripheral surface of this vicinity and the carrier on which the electrostatic latent image is formed is always constant. As a result, the entire sleeve tube can be rotated without eccentricity, and the distance between the entire outer peripheral surface of the sleeve tube and the image carrier is always constant. Is supplied to. Therefore, the unevenness of the image density and the unevenness of the width of the line image do not occur.

Here, when the electrode member elastically presses the inner peripheral surface of the sleeve tube,
Accurate pressure contact can be made according to the shape of the inner peripheral surface.

When the electrode member is arranged inside the sleeve tube, the contact portion where the electrode member contacts the sleeve tube is located inside the sleeve tube. Dust is hard to attach to the part. Therefore, it is possible to prevent electrical instability due to dust or the like adhering to the contact portion.

Further, in the case where the electrode member presses a plurality of locations on the inner peripheral surface of the sleeve element pipe and the reaction forces at these locations cancel each other out,
Since the sleeve tube rotates stably, eccentricity can be prevented more reliably.

Furthermore, when the electrode member slides on the outer peripheral surface of the fixed shaft as the sleeve tube is rotated and rotates together with the sleeve tube, the sleeve tube becomes worn. Even if the inner peripheral surface of the sleeve tube is not slid, the inner peripheral surface does not wear even if it is made of a material that is easy to form.

Furthermore, when conductive grease is applied to the sliding surface on which the electrode member slides on the outer peripheral surface of the fixed shaft, abrasion of the sliding surface can be prevented more reliably.

Furthermore, the sleeve tube has a concave portion formed on its inner peripheral surface, and the electrode member is
If one end of the electrode member is fitted into the recess and is in contact therewith, the one end fitted into the recess of the inner peripheral surface cannot slide on the inner peripheral surface, so that the electrode member is a sleeve tube. Therefore, the inner peripheral surface is not surely slid, and the inner peripheral surface is prevented from being worn due to the sliding.

Furthermore, the sleeve element pipe is rotated about the fixed shaft, which has one end portion fitted in each longitudinal end portion and the other end portion protruding from each longitudinal end portion. When the pair of flanges and the pair of bearings rotatably holding one end and the other end of each of the pair of flanges are provided, the sleeve tube can be smoothly rotated.

Furthermore, when the pair of flanges are made of synthetic resin, a relatively low cost flange can be obtained.

Furthermore, in the case where a pair of rollers which are fixed to the other end of each of the pair of flanges and have an outer diameter larger than that of the leave element tube and which rotate about the fixed shaft as a rotation center are provided. For example, by keeping the outer peripheral surface of the roller in contact with the outer peripheral surface of the image carrier, the distance between the image carrier and the sleeve tube can be reliably kept constant.

Furthermore, in the case where the fixed shaft has a groove in which the electrode member is fitted, the electrode member is fitted in the groove of the fixed shaft, and therefore, in the longitudinal direction of the fixed shaft. The electrode member does not move.

Further, when the fixed shaft and the magnet roller are integrally formed, the fixed shaft and the magnet roller can be easily manufactured.

Furthermore, a positioning member that supports one end of the fixed shaft and determines the position of the one end in the longitudinal direction of the fixed shaft, and the one end is located at a position determined by the positioning member. When the fixed shaft is provided with a biasing means for biasing the fixed shaft in the longitudinal direction, the fixed shaft is biased by the biasing means and one end thereof is located at a predetermined position, so that the fixed shaft is always regular. It will be located in the position.

[Brief description of drawings]

FIG. 1 is a front view schematically showing a developing sleeve as seen from a direction orthogonal to its longitudinal direction, with its longitudinal center portion omitted.

FIG. 2 is a front view schematically showing elasticity of a contact wire spring.

FIG. 3 is a front view showing a contact wire spring fixed to a sleeve tube.

FIG. 4 is a front view schematically showing a developing sleeve of a modified example when viewed from a direction orthogonal to the longitudinal direction thereof, and a central portion in the longitudinal direction thereof is omitted.

FIG. 5 is a front view showing a contact wire spring fixed to a sleeve tube.

FIG. 6 is a schematic diagram showing a schematic configuration of a process cartridge.

FIG. 7 is a front view schematically showing the developing sleeve as viewed in a direction orthogonal to the longitudinal direction of the developing sleeve, omitting the central portion in the longitudinal direction thereof.

[Explanation of symbols]

80 developing sleeve 82,182 Sleeve tube 84 Magnet roller 88 fixed axis 90,92 Flange 94, 96 bearings 98,100 Spacer roller 110,150 contact wire spring 200 developing device 202 Side wall of developing device 202a Side wall recess

Claims (14)

[Claims] 1. A fixed shaft which is fixed to a predetermined frame and to which a developing bias is applied, a cylindrical sleeve tube which rotates about the fixed axis as a rotation center, and a coaxial shaft which is coaxial with the sleeve tube. As described above, a cylindrical magnet roller having magnetism that is fixed inside is provided, and a developing bias is applied to the fixed shaft to adhere the developer to the outer peripheral surface of the sleeve tube, thereby statically removing the developer. In a developing device for developing an electrostatic latent image by supplying it to an electrostatic latent image, the inner peripheral surface of the sleeve tube is pressure-contacted, and the reaction force of the pressure contact is in a direction orthogonal to the fixed axis. A developing device comprising an electrode member slidably attached to a shaft. 2. The developing device according to claim 1, wherein the electrode member elastically presses the inner peripheral surface of the sleeve tube. 3. The developing device according to claim 1, wherein the electrode member is arranged inside the sleeve tube. 4. The electrode member presses a plurality of locations on the inner peripheral surface of the sleeve element pipe while pressing the reaction forces at the plurality of locations to cancel each other. Or the developing device according to item 3. 5. The electrode member slides on an outer peripheral surface of the fixed shaft as the sleeve tube is rotated and rotates together with the sleeve tube. The developing device according to any one of the above. 6. The developing device according to claim 5, wherein a conductive grease is applied to a sliding surface on which the electrode member slides on the outer peripheral surface of the fixed shaft. 7. The sleeve tube has a recess formed on the inner peripheral surface thereof, and the electrode member has one end fitted into and in contact with the recess. The developing device according to claim 1, wherein the developing device is a developing device. 8. A pair rotating around the fixed shaft as a center of rotation, having one end portion fitted in each longitudinal end portion of the sleeve tube and having the other end portion protruding from each longitudinal end portion. And a pair of bearings that rotatably retain one end and the other end of each of the pair of flanges. Development device. 9. The developing device according to claim 8, wherein the pair of flanges are made of synthetic resin. 10. A pair of rollers fixed to the other end of each of the pair of flanges and having an outer diameter larger than that of the leave tube, the pair of rollers rotating around the fixed shaft as a rotation center. The developing device according to claim 8, wherein the developing device is a developing device. 11. The developing device according to claim 1, wherein the fixed shaft has a groove in which the electrode member is fitted. 12. The developing device according to claim 1, wherein the fixed shaft and the magnet roller are integrally formed. 13. A positioning member that supports one end of the fixed shaft and determines a position of the one end in the longitudinal direction of the fixed shaft, and the one end is located at a position determined by the positioning member. 13. The developing device according to claim 1, further comprising a biasing unit that biases the fixed shaft in a longitudinal direction thereof. 14. The developing device according to claim 1, wherein the developing device is incorporated in a process cartridge in which an image carrier on which an electrostatic latent image is formed is incorporated.