JP2012032617A - Mixing and agitating structure, developing device, process cartridge and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mixing and agitating structure capable of preventing local aggregation of powder (developer or the like), and to provide a developing device, a process cartridge and an image forming apparatus.SOLUTION: The mixing and agitating structure includes an agitating section 40 which is arranged in parallel to an axial center L of rotation with a predetermined space therebetween, and rotates around the axial center L of the rotation, and a vane section 41 which is arranged along the agitating section 40, rotates together with the agitating section 40, and agitates and conveys powder. The vane section 41 is provided with an outer diameter side flat surface section 50 having a function of pushing out the powder to the outer diameter direction.

Description

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

  The developer (hereinafter also referred to as toner) in the developing device used in the electrophotographic image forming apparatus needs to be circulated without being collected locally in the developing device by being stirred and conveyed. If toner accumulates locally, the degree of toner deterioration in the developing device becomes uneven. In addition, quality difference such as background contamination is caused by a difference in toner particle size in the developing device. In particular, in a developing device that employs an additional toner replenishing method, toners having different deterioration levels are additionally replenished, so that the replenished toner and the toner remaining in the developing device are aggregated without being mixed and easily accumulated locally. In view of this, a technique for mixing and stirring by providing a mixing and stirring member such as an agitator or a paddle in a place where toner easily collects has been already known.

  FIG. 19 shows a developing device using a paddle, and FIG. 20 shows a developing device using an agitator. These developing devices supply a developing roller 61 as a developer carrying member for carrying the developer on the developing housing 60 in which the developer is accommodated and developing the image carrying member, and the developer to the developing roller 61. For this purpose, a supply roller 64 and the like are assembled. A regulating member 65 having a regulating blade 65 a that regulates the thickness of the developer layer supplied to the developing roller 61 is provided. In the developing device shown in FIG. 19, a paddle 66 as a mixing and stirring member is accommodated in the developing housing 60, and in the developing device in FIG. 20, an agitator 67 as a mixing and stirring member is accommodated in the developing housing 60. The developing roller 61, the supply roller 64, and the mixing and agitating member rotate in the directions of the arrows, respectively.

  If the paddle 66 is used as a mixing and agitating member, the toner loosening effect can be obtained, but the toner conveying effect cannot be obtained. For this reason, the toner is continuously loosened only in the range indicated by the two-dot chain line shown in FIG. 19 (the range in which the toner is loosened). As described above, if the loosening is continued in the same range (area), the toner may aggregate and accumulate outside the rotation area of the paddle 66 (outside the area where the developer is loosened).

  If the agitator 67 is used as a mixing and agitating member, an effect of conveying toner can be obtained, but the developer in the vicinity of the axis 67a of the agitator 67 is difficult to move, and the axis centered in the range indicated by the two-dot chain line shown in FIG. There is a problem that toner accumulates in the area.

  For this reason, there has conventionally been a structure configured to prevent toner aggregation (Patent Document 1). In this case, the stirring mechanism is a flat stirring member disposed at a position facing the supply roller, a position where the flat plate surface of the stirring member is in contact with the supply roller, and a position where the stirring mechanism is separated from the supply roller at a predetermined interval. And a reciprocating mechanism for reciprocating between them. The reciprocating mechanism is composed of an eccentric cam and an urging spring.

  Although the toner described in Patent Document 1 prevents toner aggregation near the stirring member, the problem of toner aggregation and accumulation outside the reciprocating range of the stirring member has not been solved. In addition, since the reciprocating mechanism is composed of an eccentric cam and an urging spring, the configuration is complicated. Further, if the stirring member operates (reciprocates) through the reciprocating mechanism in a state where the toner is filled, the toner may enter the reciprocating mechanism and hinder the movement.

  In view of such circumstances, an object of the present invention is to provide a mixing and stirring structure, a developing device, a process cartridge, and an image forming apparatus capable of preventing local aggregation of powder (developer etc.).

  The mixing and stirring structure according to the present invention includes a stirring unit that is arranged in parallel with the rotation axis at a predetermined interval and rotates around the rotation axis, and is arranged along the stirring unit and rotates together with the stirring unit. A blade portion that stirs and conveys the body, and the blade portion is provided with an outer diameter side flat surface portion that has a function of extruding powder in the outer diameter direction.

  According to the mixing and agitating structure of the present invention, since the agitating part is arranged in parallel with the rotation axis at a predetermined interval, the powder near the rotation axis can easily move and the accumulation of powder near the rotation axis can be prevented. . In addition, the powder can be conveyed by the blade portion. Further, the powder is loosened by the stirring unit. And the powder which collided with the outer diameter side flat surface part is rebounded by the outer diameter side flat surface part. At that time, the incident angle and the reflection angle of the powder are equal. Therefore, the powder is pushed out to the outer side (outer diameter side) of the rotating radius of the stirring unit. As a result, with the rotation of the mixing and stirring structure, the toner is pushed out of the rotation area, and a toner circulation area is formed in a larger area than the rotation area of the mixing and stirring structure.

  The stirring part and the blade part may be an integrally molded product. By making it an integrally molded product, it becomes excellent in strength. Further, the blade portion may be flexible. As described above, if the blade portion is flexible, the blade portion can be brought into sliding contact with a wall surface or the like in the vicinity of the blade portion, and powder such as a wall surface in sliding contact can be scraped off. .

  When the angle formed between the tangential direction of the rotation locus of the stirring portion side edge of the outer diameter side flat surface portion and the outer diameter side flat surface portion is θ, −45 ° <θ <+ 90 ° can be satisfied. By setting the angle of the outer diameter side flat surface portion within this range, it becomes possible to stably extrude the powder in the outer diameter direction.

  It is preferable that the outer diameter side flat surface portion is located on the outer diameter side with respect to the rotation locus of the stirring portion side edge except for the stirring portion side edge. By setting in this way, the powder circulation region can be stably increased.

  A plurality of outer diameter side flat surface portions having different angles with respect to the tangential direction of the rotation locus of the stirring portion side edge can be arranged along the rotation axis. By setting in this way, it is possible to dispose an outer diameter side flat surface portion having a different pushing effect in the outer diameter direction. For this reason, aggregation of powder can be more effectively prevented by disposing an outer diameter side flat surface portion having a large extrusion effect at a portion where the powder tends to accumulate (for example, the wall side).

  An outer-diameter flat surface portion having a different width dimension in a direction orthogonal to the rotation axis can be disposed along the rotation axis. If the width dimension is large, the contact area with the powder becomes large, and the extrusion effect in the outer diameter direction becomes large.

  The developing device of the present invention includes a developer carrying member, a developer supplying member for supplying the developer to the developer carrying member, and a conveying member that conveys the developer to the developer supplying member while stirring the developer. And a developing device comprising a regulating member that regulates the thickness of the developer layer supplied to the developer carrying member, wherein the conveying member is disposed near the upper side of the developer supplying member, and the conveying member The mixed stirring structure is used.

  According to the developing device of the present invention, it is possible to enlarge the circulation region of the developer that is powder.

  Moreover, it is preferable that the dimension between the edge of the outer diameter side flat surface portion on the side opposite to the stirring portion and the developer supply member is 4 mm or less. By setting in this way, a larger circulation region can be obtained by the synergistic effect of the effect of feeding the developer by the developer supply member and the effect of feeding the developer by the blade portion.

  It is preferable that the dimension between the edge on the side opposite to the stirring portion of the outer diameter side flat surface portion and the regulating member is 2 mm or less. By setting in this way, it is possible to prevent the developer from being accumulated between the edge on the side opposite to the agitating portion of the outer diameter side flat surface portion and the regulating member.

  It is possible that the direction in which the developer is pushed out by the outer diameter side flat surface portion and the developer circulation direction formed by the developer supply member substantially coincide with each other. By setting in this way, the circulation of the developer is promoted.

  The process cartridge of the present invention is a process cartridge that is detachably attached to the main body of the image forming apparatus, and at least the developing device and an image carrier on which an electrostatic latent image is formed are integrated. It is.

  According to the process cartridge of the present invention, the developing device capable of obtaining a large circulation area is provided, and is detachably attached to the main body of the image forming apparatus.

  The image forming apparatus of the present invention uses the process cartridge. According to this image forming apparatus, the developing device can obtain a large circulation area.

  With the mixing and stirring structure of the present invention, the powder circulation region can be increased, local agglomeration of powder can be prevented, and powder stirring and powder conveyance can be performed stably.

  If the stirring part and the blade part are integrally formed products, they are excellent in strength and can stably exhibit the stirring / conveying function over a long period of time. If the blade portion is flexible, powder such as a wall surface can be scraped off, and the powder can be effectively prevented from accumulating near the wall surface.

  By setting the angle of the outer diameter side flat surface portion to −45 ° <θ <+ 90 °, extrusion of the powder in the outer diameter direction is stabilized, and local aggregation of the powder can be further prevented.

  If the part excluding the stirrer side edge is located on the outer diameter side of the rotation trajectory of the stirrer side edge, the powder circulation region can be stably increased, and the local powder Aggregation can be stably prevented.

  By arranging the outer diameter side flat surface part having different angles or by arranging the outer diameter side flat surface part having different width dimensions, the powder is arranged corresponding to the part where the powder tends to accumulate and the part where the powder is difficult to accumulate. be able to. For this reason, an efficient stirring / conveying function can be exhibited, and local aggregation of the powder can be efficiently prevented.

  In the developing device of the present invention, local aggregation of the developer can be prevented, and high-quality image formation is possible. The dimension between the edge on the side opposite to the agitating portion of the outer diameter side flat surface portion and the developer supply member should be 4 mm or less, or between the edge on the side opposite to the agitating portion of the outer diameter side flat surface portion and the regulating member By making the size of 2 mm or less, it is possible to prevent the developer from being accumulated, and image formation is stabilized.

  By making the direction in which the developer is pushed out by the flat surface portion on the outer diameter side and the developer circulation direction formed by the developer supply member the same direction, the effect of preventing the developer from being accumulated can be enhanced.

  In the process cartridge and the image forming apparatus of the present invention, a large circulation area can be obtained in the developing device, and high-quality image formation is possible.

It is sectional drawing of the image development apparatus using the mixing stirring structure of this invention. 1 is an overall configuration diagram of an image forming apparatus using a developing device of the present invention. It is a perspective view of the mixing stirring structure of this invention. It is a principal part front view which shows operation | movement of the mixing stirring structure shown in the said FIG. It is a principal part front view which shows operation | movement of the mixing stirring structure shown in the said FIG. It is a principal part front view which shows the 1st modification of the mixing stirring structure of this invention. It is a principal part front view which shows the 2nd modification of the mixing stirring structure of this invention. It is sectional drawing of the image development apparatus of the state by which the mixing stirring structure is arrange | positioned in the other arrangement position. It is sectional drawing of the image development apparatus of the state by which the mixing stirring structure is arrange | positioned in another arrangement position. FIG. 10 is a cross-sectional view of a main part of the developing device shown in FIG. 9. It is a principal part front view which shows the 3rd modification of the mixing stirring structure of this invention. It is sectional drawing of the other image development apparatus using the mixing stirring structure of this invention. It is a perspective view which shows the 4th modification of the mixing stirring structure of this invention. It is a perspective view which shows the 5th modification of the mixing stirring structure of this invention. It is a perspective view which shows the 6th modification of the mixing stirring structure of this invention. 15 shows the mixing and stirring structure shown in FIG. 15, wherein (a) is a cross-sectional view of a portion of FIG. 15, and (b) is a cross-sectional view of a portion of FIG. It is a perspective view which shows the 7th modification of the mixing stirring structure of this invention. It is sectional drawing of the mixing and stirring structure shown in the said FIG. It is principal part sectional drawing of the conventional image development apparatus. It is principal part sectional drawing of the other conventional image development apparatus.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention according to embodiments shown in the drawings will be described.

  FIG. 2 is a schematic configuration diagram showing an embodiment of the image forming apparatus according to the present invention. The image forming apparatus of the present invention shown in FIG. 2 includes four process units 1Y, 1C, 1M, and 1BK. Each process unit 1Y, 1C, 1M, 1BK is configured to be detachable from the image forming apparatus main body 100.

  The process units 1Y, 1C, 1M, and 1BK have the same configuration except that they contain toners of different colors of yellow, cyan, magenta, and black corresponding to the color separation components of the color image. Therefore, the configuration of one process unit 1Y will be described as an example.

  The process unit 1Y includes a photosensitive member 2 as an image carrier, a charging roller 3 as a charging unit that charges the surface of the photosensitive member 2, and a developing device 4 as a developing unit that forms a toner image on the surface of the photosensitive member 2. And a photosensitive member cleaning blade 5 as a cleaning means for cleaning the surface of the photosensitive member 2.

  Above each of the process units 1Y, 1C, 1M, and 1BK, an exposure device 7 is disposed as an exposure unit that exposes the surface of the photoreceptor 2. An intermediate transfer unit 6 is disposed below each process unit 1Y, 1C, 1M, 1BK. The intermediate transfer unit 6 has an intermediate transfer belt 10 constituted by an endless belt. The intermediate transfer belt 10 is stretched around a driving roller 8 and a driven roller 9 and is configured to be able to run around in the direction of the arrow in the figure.

  On the inner peripheral surface of the intermediate transfer belt 10, four primary transfer rollers 11Y, 11C, 11M, and 11BK are disposed as primary transfer means. Each of the primary transfer rollers 11Y, 11C, 11M, and 11BK is in pressure contact with the inner peripheral surface of the intermediate transfer belt 10 at a position facing the photoreceptor 2, and each photoreceptor 2 is in contact with the intermediate transfer belt 10 by this pressure contact. A primary transfer nip is formed in pressure contact with the outer peripheral surface.

  A secondary transfer roller 12 as a secondary transfer unit is disposed at a position facing the driving roller 8 that stretches the intermediate transfer belt 10. The secondary transfer roller 12 is in pressure contact with the outer peripheral surface of the intermediate transfer belt 10 and forms a secondary transfer nip at the pressure contact portion.

  The intermediate transfer unit 6 includes a belt cleaning device 21 for cleaning the surface of the intermediate transfer belt 10. A waste toner container 22 for storing waste toner is disposed below the intermediate transfer unit 6. A waste toner transfer hose (not shown) extending from the belt cleaning device 21 is connected to the entrance of the waste toner container 22.

  Under the image forming apparatus main body 100, a recording medium accommodating portion 13 that accommodates a recording medium P such as paper or an OHP sheet is disposed. The recording medium accommodating portion 13 is provided with a supply roller 14 for carrying out the recording medium P and the like.

  In the image forming apparatus main body 100, a conveyance path R <b> 1 for guiding the recording medium P upward from the recording medium container 13 is disposed. A pair of registration rollers 15a and 15b are disposed upstream of the secondary transfer nip formed by the drive roller 8 and the secondary transfer roller 12 in the transport direction of the transport path R1 (downward in the drawing). Further, the fixing device 16 is disposed downstream of the secondary transfer nip in the transport direction of the transport path R1 (upward in the drawing). The fixing device 16 includes a heating roller 17 and a pressure roller 18. The heating roller 17 and the pressure roller 18 are in pressure contact with each other, and a fixing nip is formed at the pressure contact portion.

  A pair of discharge rollers 19a and 19b are disposed at the downstream end of the transport path R1 in the transport direction. In addition, a stock unit 20 on which the recording medium P is loaded is formed by denting the upper surface of the image forming apparatus main body 100 inward.

The basic operation of the image forming apparatus will be described below with reference to FIG.
In the process unit 1Y, the photosensitive member 2 is rotated in the direction of the arrow in the figure, and the surface of the photosensitive member 2 is charged to a uniform high potential by the charging roller 3. Next, a laser beam is irradiated from the exposure device 7 to the surface of the photoconductor 2 based on the image data, and the potential of the irradiated portion is lowered to form an electrostatic latent image. The toner charged by the developing device 4 is electrostatically transferred to the portion of the electrostatic latent image formed on the surface of the photoreceptor 2 to form a yellow toner image (visualization).

  The primary transfer roller 11Y is applied with a constant voltage or a constant current controlled voltage having a polarity opposite to the charging polarity of the toner. As a result, a transfer electric field is formed in the primary transfer nip between the primary transfer roller 11Y and the photoreceptor 2. Then, in the primary transfer nip, the toner image on the rotating photoconductor 2 is primarily transferred to the intermediate transfer belt 10 running in the direction of the arrow in the figure.

In each of the other process units 1C, 1M, and 1BK, similarly, a toner image is formed on the photoreceptor 2, and the four color toner images are primarily transferred to the intermediate transfer belt 10 so as to overlap each other.

  Further, the surface of the photoreceptor 2 after the primary transfer process is cleaned by the photoreceptor cleaning blade 5 to remove residual toner. Further, the residual charge remaining on the surface of the photoreceptor 2 is neutralized by a neutralizing lamp (not shown).

  On the other hand, the recording medium P stored in the recording medium storage unit 13 is sent out to the transport path R1 by rotating the supply roller 14. The sent recording medium P is temporarily stopped by the registration rollers 15a and 15b.

  Further, a voltage having a polarity opposite to the charging polarity of the toner is applied to the secondary transfer roller 12 to form a transfer electric field in the secondary transfer nip. Alternatively, a similar transfer electric field may be formed by applying a voltage having the same polarity as the charging polarity of the toner to the driving roller 8 facing the secondary transfer roller 12. Thereafter, the driving of the registration rollers 15a and 15b is resumed, and the recording medium P is sent to the secondary transfer nip in synchronism with the toner image on the intermediate transfer belt 10. Then, the toner image on the intermediate transfer belt 10 is secondarily transferred collectively onto the recording medium P by the transfer electric field formed in the secondary transfer nip. Further, after the secondary transfer, the toner remaining on the surface of the intermediate transfer belt 10 is removed by the belt cleaning device 21, and the removed toner is collected in the waste toner container 22.

  The recording medium P to which the toner image has been transferred is conveyed to the fixing device 16. The recording medium P sent to the fixing device 16 is sandwiched between the heating roller 17 and the pressure roller 18 and heated and pressurized, and the toner image is fixed on the recording medium P. Thereafter, the recording medium P is discharged to the stock unit 20 by the discharge rollers 19a and 19b.

  Incidentally, as shown in FIG. 1, the process cartridge is a unit in which a photosensitive member (photosensitive drum) 2 and a developing device (developing means) 4 are integrated. The developing device 4 includes a developing roller 31 as a developer carrying member, a supply roller 34 as a developer supply member for supplying the developer to the developing roller 31, and a developer while stirring the developer. A mixing and stirring structure (mixing and stirring member) 33 for conveying the developer to the supply roller 34 is assembled. In addition, a regulating member 35 that regulates the thickness of the developer layer supplied to the developing roller 31 is provided. A toner container (not shown) is detachably disposed on the upper portion of the developing housing 30, and toner as a developer is supplied to the developing housing 30 from the toner container.

The supply roller 34 is composed of a sponge roller or the like to which foamed polyurethane made semiconductive by mixing carbon is mixed on the outer periphery of a metal core. In the embodiment of the present invention, the diameter of the cored bar is about 6 mm, and the outer diameter of the sponge portion is about 12 mm. Further, the nip with the developing roller 31 is set to 2 mm, and the rotation speed ratio is set to 1. The developing roller 31 has a metal core, and the outer periphery has a conductive rubber whose volume resistance is adjusted to about 10 ⁵ to 10 ⁷ Ω (for example, conductive urethane rubber or silicone rubber can be used). It consists of In the examples of the present invention, those having a rubber hardness Hs75, a core metal diameter of 6 mm, and a rubber outer diameter of 12 mm were used. The regulating member 35 has a regulating blade 35a made of a metal plate such as SUS having a plate thickness of about 0.1 mm, for example, and the amount of toner on the developing roller 31 is brought into contact with the developing roller 31 by contacting the regulating blade 35a with the developing roller 31. It is the composition which adjusts.

  Note that control of the amount of toner on the developing roller 31 is extremely important for stabilizing the developing characteristics, and even in a normal product, the contact pressure of the blade 35a against the developing roller 31 (normal linear pressure 20 to 60 N / m). The contact nip position (usually about 0.5 ± 0.5 mm from the blade tip) is an item that should be strictly controlled, and is appropriately selected according to the characteristics of the toner 55, the developing roller 31, the supply roller 34, and the like. It is determined.

  In the embodiment of the present invention, the developing blade 35a is made of SUS material having a plate thickness of 0.1 mm, the linear pressure is 45 N, the nip position is 0.2 mm from the tip, and the length from the support end of the developing blade to the free end ( A stable toner layer is formed on the developing roller 31 by setting the free length to 14 mm.

  As shown in FIG. 3, the mixing and stirring structure 33 is disposed along the stirring unit 40, and the stirring unit 40 that is disposed in parallel with the rotation axis L at a predetermined interval and rotates about the rotation axis L. And a blade portion 41 that rotates together with the stirring portion 40 and stirs and conveys the powder (toner).

  That is, the mixing and stirring structure 33 includes short shaft-shaped end shaft portions 43 and 43 disposed at both ends in the axial direction, and a shaft-shaped shaft connected to the end shaft portion 43 via the crank portion 44. As shown in FIG. 4, a flat blade portion 41 is connected to the stirring portion 40 so as to be orthogonal to the axis of the crank portion 44.

  In this embodiment, as shown in FIG. 4, the thickness t of the blade portion 41 is about 0.5 mm, and the free end (anti-stirring portion side edge) 46 of the outer diameter side flat surface portion 50 is fixed to the fixed end. The dimension X up to (stirring portion side edge) 45 is about 3 mm. The dimension from the rotation axis L to the axis of the stirring unit 40 is about 4.2 mm. And the notch part is provided in the outer-diameter surface of the stirring part 40, and one long side side of the blade | wing part 41 is fitted by this notch part. At this time, for example, the blade portion 41 is integrally bonded to the stirring portion 40 via a double-sided tape.

  In the mixing and stirring structure 33 configured as described above, when the end shaft portions 43 and 43 are driven to rotate, the stirring portion 40 is disposed in parallel with the rotation axis L at a predetermined interval. Nearby toner can easily move, and toner accumulation near the rotation axis can be prevented. In addition, the toner can be conveyed by the blade portion 41. Further, the toner is loosened by the stirring unit 40. As shown in FIG. 4, the toner 55 existing between the rotation trajectory C of the stirring unit 40 and the trajectory D of the free end 46 of the blade portion 41 collides with the outer diameter side flat surface portion 50 of the blade portion 41 and rebounds. At that time, the incident angle θ1 and the reflection angle θ2 of the toner 55 are equal. Therefore, the toner 55 is pushed out of the rotation radius of the stirring unit 40 (in the direction of the white arrow G). As a result, with the rotation of the mixing and stirring structure, the toner is pushed out of the rotation area, and a toner circulation area is formed in a larger area than the rotation area of the mixing and stirring structure. As described above, when the mixing and stirring structure 33 is rotationally driven, a toner circulation region is formed in a region larger than the rotation region of the mixing and stirring structure 33, and an effect of preventing occurrence of toner accumulation (aggregation) is obtained.

  In the embodiment, the outer diameter side flat surface portion 50 of the blade portion 41 is disposed in parallel with the tangent S (see FIG. 6) of the rotation locus of the edge of the blade portion 41 on the stirring portion side. As shown in FIG. 6, the outer diameter side flat surface portion 50 may make a predetermined angle with respect to the tangent line S. If this angle is θ, −45 ° <θ <+ 90 ° can be established.

  As shown in FIG. 7, the outer diameter side flat surface portion 50 of the blade portion 41 may be a concave curved surface having a curvature radius R. Thus, by making it into a concave curved surface, the push-out effect to the outer side (outer diameter side) of a rotation area | region can be heightened.

  By the way, as shown in FIG. 2 with respect to the rotation direction of the supply roller 34, the mixing stirring structure 33 is rotated in the opposite direction so that the toner between them is pushed out by the rotation of the mixing stirring structure 33. The toner is moved with respect to the toner outside the rotating range of the mixing and stirring member. At this time, it was confirmed that there was an effect of moving up to a rotation range of 0 to 2 mm, although it varied depending on the shape of the mixing stirring member and the number of rotation.

  In this embodiment, as shown in FIG. 1, the mixing and stirring structure 33 is located in the vicinity (upper side) of the supply roller 34. The surface of the supply roller 34 is generally a sponge and has irregularities. For this reason, the supply roller 34 rotates while taking the toner into the uneven portion of the surface, so that the toner near the surface of the supply roller is also conveyed and convection occurs. At this time, the surface of the supply roller 34 generally moves from 0 to 2 mm within the range in which the toner moves, although it varies depending on the material of the supply roller 34, the rotation speed, and the toner. Therefore, if these two are combined, the supply roller is at a position where L1 ≦ 4 mm, where L1 (see FIG. 8) is the closest distance between the free end 46 of the blade portion 41 of the mixing stirring structure 33 and the surface of the supply roller. A larger toner circulation region is formed by the synergistic effect of the effect of feeding the toner by 34 and the effect of feeding the toner by the mixing and stirring member of the present invention.

  Further, regarding the positional relationship between the mixing and stirring structure 33 and the regulating blade 35a, if the closest approach distance between the regulating blade tip 35b and the free end 46 of the blade portion 41 of the mixing and stirring structure 33 is L2 (see FIG. 9), L2 ≦ 2 mm is preferable. The toner on the developing roller 31 does not become a thin layer on the developing roller 31 by the regulating blade 35a, and the scraped toner tends to accumulate at the regulating blade tip 35b. By setting the closest approach distance to the free end 46 of 41 within 2 mm, it is possible to prevent toner from accumulating (aggregating) at the regulating blade tip 35b as shown in FIG.

  The material of the blade part 41 is preferably a flexible material. By using a flexible material for the blade portion 41 as shown in FIG. 11, the blade portion 41 can be pressed against the wall 30a of the developing device 4, and the toner in the vicinity of the wall where toner tends to accumulate is scraped off. An effect is obtained. A PET sheet having a thickness of 0.5 mm can be used as the material of the blade portion 41 as a flexible material. In this case, in consideration of scraping property, the rotation direction of the mixing and stirring structure 33 is different from those in the above embodiments as shown in FIG.

  In each of the embodiments described above, the number of the mixing and stirring structure 33 is one for the developing housing 30, but may be a plurality (two in the illustrated example) as shown in FIG. 12. As described above, in the developing device in which a plurality of the mixing and stirring members 12 are installed, the toner circulation indicated by the arrow T is promoted by the respective mixing and stirring members by the synergistic effect of the toner feeding effect obtained by the respective mixing and stirring members. As a result, the effect of preventing toner accumulation (aggregation) can be enhanced.

  The toner circulation direction in the developing device 4 is determined by the rotation direction of the supply roller 34. Therefore, when a plurality of mixing and stirring structures 33 of the present invention are installed, as shown in FIG. 7, the direction in which the toner 55 is pushed out by the mixing and stirring structure 33 of the present invention and the direction of circulation of the toner 55 formed by the supply roller 34 ( When the rotation direction of the mixing and stirring structure 33 of the present invention is determined so that the direction of the arrow T) also coincides with the downstream mixing and stirring structure 33, the circulation of the toner 55 is further promoted. As a result, the effect of preventing the toner 55 from collecting (aggregating) can be enhanced.

  In FIG. 13, the stirring part (support part) 40 and the blade | wing part 41 of the mixing stirring structure 33 are comprised by the integrally molded product. Thus, by integrating, it is possible to reduce the number of parts and to suppress an increase in cost. In the embodiment of the present invention, by resin molding, the length from the rotation axis L to the stirring portion tip 40 a is 5 mm, the thickness t of the blade portion 41 is 0.5 mm, and the fixed end 45 to the free end 46 of the blade portion 41. The length X is 3 mm.

  Next, FIG. 14 is a diagram in which the stirring unit 40 and the blade unit 41 are divided. That is, the stirring part 40 is divided into a pair of end parts 40a and 40b and an intermediate part 40c, and the blade part 41 is correspondingly divided into a pair of end parts 41a and 41b and an intermediate part 41c. It is divided into. That is, the end part 41a is attached to the end part 40a, the end part 41b is attached to the end part 40b, and the intermediate part 41c is attached to the intermediate part 40c.

  In this case, the end portions 40a and 40b and the intermediate portion 40c are arranged on the opposite side with respect to the rotation axis L by 180 degrees. Therefore, the end portions 40a and 40b and the intermediate portion 40c are connected by the connecting portions 44b and 44c. Thus, by dividing, the force applied to the blade part 41 can be dispersed and the deterioration of the member can be alleviated.

  In FIG. 15, a plurality of outer diameter side flat surface portions 50a, 50c, and 50b having different angles with respect to the tangential direction of the rotation locus of the stirring portion side edge are arranged along the rotation axis. That is, the blade portion 41 has end portions 41d and 41e having the outer diameter side flat surface portions 50a and 50b and a central portion 41f having the outer diameter side flat surface portion 50c. In this case, as shown in FIG. 16A, a part (50c) where the angle θ is 0 °, and a part (50a) where θ is about 45 ° as shown in FIG. 16B. 50b). Note that inclined portions 51 and 51 are provided between the end portion 41d and the central portion 41f, and between the central portion 41f and the end portion 41e.

  At the end of the developing device 4 in the longitudinal direction, the toner tends to accumulate as it approaches the wall 30a. Therefore, by attaching the blade portion 41 having an angle θ formed between the tangent to the rotation locus of the fixed end 45 of the mixing stirring structure 33 and the blade surface toward the longitudinal end portion, the rotation region particularly at the blade end portion is attached. The effect of pushing out the toner to the outside increases, and toner accumulation (aggregation) can be prevented even in the vicinity of the longitudinal wall.

  Next, FIG. 17 shows a configuration in which outer diameter side flat surface portions 50d, 50f, and 50e having different width dimensions in a direction orthogonal to the rotation axis are arranged along the rotation axis. In this case, the blade portion 41 has end portions 41g and 41h having the outer diameter side flat surface portions 50d and 50e, and a central portion 41i having the outer diameter side flat surface portion 50f. The central outer diameter side flat surface portion 50f has an angle θ of 0 °, and the outer diameter side flat surface portions 50d and 50e of the end portions have an angle θ of about 45 °. As shown in FIG. 18, when the width dimension of the outer diameter side flat surface part 50f at the center is L3 and the width dimension of the outer diameter side flat surface parts 50d and 50e at the end is L4, L3 <L4. . Note that inclined portions 52 and 52 are provided between the end portion 41g and the central portion 41i and between the central portion 41i and the end portion 41h.

  By setting in this way, the contact area between the outer diameter side flat surface portion 50 and the toner 55 at the end is increased, and in particular, the effect of sending the toner 55 to the outside of the rotation region at the blade end can be enhanced. Accumulation (aggregation) can be prevented.

  According to the process cartridge of the present invention, the developing device 4 capable of obtaining a large circulation area is provided, and the image forming apparatus main body 100 is detachably mounted.

  Further, since the image forming apparatus of the present invention uses the process cartridge, the developing device can obtain a large circulation area.

  Therefore, in the process cartridge and the image forming apparatus of the present invention, a large circulation area can be obtained in the developing device, and high-quality image formation is possible.

In addition, this invention is not limited to the above-mentioned Example, Of course, a various change can be added in the range which does not deviate from the summary of this invention. Examples of the image forming apparatus according to the present invention include an electrophotographic copying machine, a laser beam printer, and a facsimile machine.
The interval (predetermined interval) between the rotation axis L and the stirring unit can be variously changed based on the size of the developing housing 30 in which the mixing and stirring structure 33 is accommodated. In the embodiment, the mixing and stirring structure 33 is used for the developing device of the image forming apparatus. However, the use of the mixing and stirring structure 33 is not limited to the developing device of the image forming apparatus, and powder such as toner is used. It can be used in various devices for mixing and stirring the body.

2 Image carrier 4 Developing device 31 Developing roller (Developer carrier)
33 Mixing and stirring structure (mixing and stirring member)
34 Supply roller (developer supply member)
35 Regulating member 45 Stirrer side edge (fixed end)
46 Anti-stirring section side edge (free end)
50 outer diameter side flat surface portion 100 image forming apparatus main body L rotation axis

JP 2008-197321 A

Claims (13)

  An agitation unit that is disposed in parallel with the rotation axis at a predetermined interval and rotates about the rotation axis; a blade unit that is disposed along the agitation unit and rotates with the agitation unit to agitate and convey the powder; A mixing and stirring structure characterized in that an outer diameter side flat surface portion having a function of extruding powder in the outer diameter direction is provided on the blade portion.   The mixed stirring structure according to claim 1, wherein the stirring portion and the blade portion are integrally formed products.   The mixed stirring structure according to claim 1, wherein the blade part has flexibility.   The angle between the tangential direction of the rotation trajectory of the stirring portion side edge of the outer diameter side flat surface portion and the outer diameter side flat surface portion is defined as -45 ° <θ <+ 90 °, where θ is defined as θ. The mixed stirring structure according to any one of claims 1 to 3.   5. The outer diameter side flat surface portion has a portion excluding the stirring portion side edge positioned on the outer diameter side with respect to the rotation locus of the stirring portion side edge. 6. 2. A mixed stirring structure according to 1.   6. A plurality of outer diameter side flat surface portions having different angles with respect to the tangential direction of the rotation locus of the stirring portion side edge are arranged along the rotation axis. 2. A mixed stirring structure according to 1.   The mixing according to any one of claims 1 to 5, wherein an outer diameter side flat surface portion having a different width dimension in a direction orthogonal to the rotation axis is disposed along the rotation axis. Stir structure. A developer carrying member, a developer supplying member for supplying the developer to the developer carrying member, a conveying member for stirring the developer and conveying the developer to the developer supplying member, and a developer carrying member. A developing device including a regulating member that regulates the thickness of the supplied developer layer,
The development characterized in that the conveying member is disposed in the vicinity of the upper part of the developer supply member, and the mixing and stirring structure according to any one of claims 1 to 7 is used for the conveying member. apparatus.   The developing device according to claim 8, wherein a dimension between an edge of the outer diameter side flat surface portion on the side opposite to the stirring portion and the developer supply member is 4 mm or less.   The developing device according to claim 8 or 9, wherein a dimension between an edge of the outer diameter side flat surface portion on the side opposite to the agitation portion and the regulating member is 2 mm or less.   The direction in which the developer is pushed out by the flat surface portion on the outer diameter side and the developer circulation direction formed by the developer supply member substantially coincide with each other. Development device.   12. A process cartridge that is detachably attached to an image forming apparatus main body, wherein at least the developing device according to claim 8 and an image carrier on which an electrostatic latent image is formed. And a process cartridge that is integrally formed.   An image forming apparatus using the process cartridge according to claim 12.

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