JP2013068715A - Developing device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device and an image forming apparatus with less deterioration of a developer.SOLUTION: A developing device 14Y comprises: a rotating conveying body 141 for conveying a developer to the surface of a body 11Y to be developed by rotating while maintaining a developer disposed adjacent to the body to be developed on the surface; a plate-like layer regulating member 147 for regulating a layer thickness of the developer disposed with a gap between the surface of the rotating conveying body at upstream from the body to be developed in a conveyance direction F in which the developer is conveyed by the rotation of the rotating conveying body; and a plurality of interference members 148 for interfering with the flow of the developer which are disposed at upstream in the conveyance direction from the layer regulating member 147 and each of which extends toward the surface of the rotating conveying body 141 and is arranged in a first direction DE intersecting the flow of the developer flowing toward the layer regulating member 147.

Description

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

  For example, Patent Document 1 discloses a developing device having a developing roller that supplies a developer to a photoreceptor. The developing device includes a regulating member that regulates the amount of developer on the developing roller. A supply roller having a groove formed on the surface is provided above the developing roller.

JP 2007-108640 A

  An object of the present invention is to provide a developing device and an image forming apparatus in which the charge amount of the developer is increased.

The developing device according to claim 1 is:
A rotating conveyance body that is arranged adjacent to the development target and rotates while holding the developer on the surface to convey the developer to the surface of the development target;
Layer regulation that regulates the layer thickness of the developer disposed with a gap between the surface and the upstream side in the transport direction in which the developer is transported by the rotation of the rotating transport body. Members,
Arranged in a first direction that is arranged upstream of the layer regulating member in the conveying direction and that extends toward the surface of the rotary conveying member and intersects the flow of developer flowing toward the layer regulating member. And a plurality of interference members that interfere with the flow of the developer.

  The developing device according to claim 2 includes a plurality of the interference members arranged in the first direction and also in the developer flow direction so as to be two-dimensionally arranged in a zigzag manner as a whole. It is characterized by being.

An image forming apparatus according to claim 3
A development target on which an electrostatic latent image is formed on the surface and the electrostatic latent image is developed with a developer;
A developing device for developing the object to be developed with a developer;
The developing device is
A rotating and conveying body that is arranged adjacent to the object to be developed and conveys the developer to the surface of the object to be developed by rotating while holding the developer on the surface;
A plate shape that regulates the layer thickness of the developer, with a gap between the surface and the upstream side of the development target in the transport direction in which the developer is transported by the rotation of the rotary transport body. A layer regulating member of
Arranged in a first direction that is arranged upstream of the layer regulating member in the conveying direction and that extends toward the surface of the rotary conveying member and intersects the flow of developer flowing toward the layer regulating member. And a plurality of interference members that interfere with the flow of the developer.

  The developing device according to the first aspect and the image forming apparatus according to the third aspect have a larger charge amount than the case where no interference member is provided.

  In the developing device according to the second aspect, as compared with the case where the interference members are irregularly arranged, it is possible to suppress unevenness in the charge amount of the developer.

1 is a configuration diagram illustrating an embodiment of an image forming apparatus of the present invention. FIG. 2 is a plan view of the developing device shown in FIG. 1. It is a longitudinal cross-sectional view of a developing device. FIG. 5 is a diagram of a layer regulating member and an interference member as viewed from above the developing device. It is sectional drawing which shows the part of a layer control member and an interference member.

  Embodiments of the present invention will be described below with reference to the drawings.

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

  The image forming apparatus 1 shown in FIG. 1 has image forming units 10Y, 10M, 10C, and 10K arranged in parallel for each color of yellow (Y), magenta (M), cyan (C), and black (K). The tandem type color printer is capable of printing a single color image and printing a full color image composed of four color toner images. The image forming apparatus 1 includes toner cartridges 18Y, 18M, 18C, and 18K that store toner of each color of YMCK.

  Since the four image forming units 10Y, 10M, 10C, and 10K have substantially the same configuration, the image forming unit 10Y corresponding to yellow will be described as a representative example. The image forming unit 10Y includes a photoreceptor 11Y, a charger 12Y, an exposure device 13Y, a developing device 14Y, a primary transfer device 15Y, and a photoreceptor cleaner 16Y.

  The photoconductor 11Y has a photoconductor layer on a cylindrical substrate, holds an image formed on the surface, and rotates in the direction of arrow A around the axis of the cylinder. The charger 12Y, the exposure device 13Y, the developing device 14Y, the primary transfer device 15Y, and the photoconductor cleaner 16Y are sequentially arranged around the photoconductor 11Y. The photoreceptor 11Y corresponds to an example of a member to be developed according to the present invention.

  The charger 12Y charges the surface of the photoreceptor 11Y. The charger 12Y is a charging roll that contacts the surface of the photoreceptor 11Y. A voltage having the same polarity as that of the toner in the developing device 14Y is applied to the charging roll, and the surface of the contacted photoreceptor 11Y is charged. As the charger 12Y, a corona discharger that is not in contact with the photoreceptor 11Y can be employed in addition to the charging roll.

  The exposure device 13Y includes a light emitter that emits laser light based on an image signal supplied from the outside of the image forming apparatus 1, and a rotary polygon mirror that scans the photoconductor 11Y with the laser light. By irradiating 11Y with laser light, the surface of the photoreceptor 11Y is exposed.

  The developing device 14Y develops the surface of the photoreceptor 11Y using a two-component developer composed of toner and a magnetic carrier. Toner is supplied from the toner cartridge 18Y to the developing device 14Y. The toner is mixed with the magnetic carrier in the developing device 14Y. The magnetic carrier is obtained, for example, by applying a resin coating to the surface of iron powder. The toner particles have, for example, a binder resin, a colorant, and a release agent. The developing device 14Y charges the toner and the magnetic carrier by stirring the developer in which the magnetic carrier particles and the toner particles are mixed, and develops the surface of the photoreceptor 11Y with the charged toner.

  The primary transfer unit 15Y is a roll facing the photoconductor 11Y with the intermediate transfer belt 30 interposed therebetween. The primary transfer unit 15Y has a conductive elastic layer on the surface, and a toner image on the photoreceptor 11Y is statically applied to the intermediate transfer belt 30 by applying a voltage having a polarity opposite to the charging polarity of the toner. Electrosuction. The photoconductor cleaner 16Y has a cleaning blade that contacts the surface of the photoconductor 11Y, and cleans the surface of the photoconductor 11Y after transfer.

  The image forming apparatus 1 also includes an intermediate transfer belt 30, a fixing device 60, a paper transport unit 80, and a control unit 1 </ b> A that controls each part of the image forming apparatus 1. The intermediate transfer belt 30 is an endless belt made of a resin material containing an antistatic agent. The intermediate transfer belt 30 is stretched around belt support rolls 31 to 35 and circulates in the direction indicated by the arrow B passing through the image forming units 10Y, 10M, 10C, and 10K and the secondary transfer unit 50. The toner images of the respective colors are transferred to the intermediate transfer belt 30 from the image forming units 10Y, 10M, 10C, and 10K. The intermediate transfer belt 30 moves while holding the toner images of these colors.

  The secondary transfer device 50 is a roll that rotates with the intermediate transfer belt 30 and the paper sandwiched between the secondary transfer unit 50 and the backup roll 34 that is one of the belt support rolls 31 to 35. The secondary transfer unit 50 has a conductive elastic layer on the surface, and a voltage having a polarity opposite to the charging polarity of the toner is applied to electrostatically attract the toner image on the intermediate transfer belt 30 to the sheet. . The belt cleaner 70 scrapes off the toner on the intermediate transfer belt 30 by bringing a blade into contact with the intermediate transfer belt 30.

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

  The paper transport unit 80 includes a take-out roll 81 that takes out the paper stored in the paper container T, a scooping roll 82 that picks up the picked-up paper, a transport roll 83 that transports the paper, and a resist that transports the paper to the secondary transfer device 50. And a discharge roll 86 for discharging the paper to the outside. The paper transport unit 80 transports along a paper transport path R that passes through the secondary transfer device 50 and the fixing device 60.

  The basic operation of the image forming apparatus 1 shown in FIG. 1 will be described. In the yellow image forming unit 10Y, the photoreceptor 11Y is rotationally driven in the direction of arrow A, and a charge is applied to the surface of the photoreceptor 11Y by the charger 12Y. . The exposure device 13Y irradiates the photoconductor 11Y with exposure light corresponding to data corresponding to each color in the image signal. The exposure device 13Y forms an electrostatic latent image on the surface of the photoconductor 11Y by irradiating the surface of the photoconductor 11Y with exposure light based on an image signal corresponding to yellow among image signals supplied from the outside. . Yellow toner is supplied from the toner cartridge 18Y to the developing device 14Y. The developing device 14Y forms a toner image by developing the electrostatic latent image with toner. The photoconductor 11Y rotates while holding the yellow toner image formed on the surface. The toner image formed on the surface of the photoreceptor 11Y is transferred to the intermediate transfer belt 30 by the primary transfer unit 15Y. After transfer, the toner remaining on the photoreceptor 11Y is collected and removed by the photoreceptor cleaner 16Y.

  The intermediate transfer belt 30 is looped around the support rolls 31 to 35 and moved in the direction of arrow B. The image forming units 10M, 10C, and 10K corresponding to colors other than yellow form toner images corresponding to the respective colors in the same manner as the image forming unit 10Y, and are transferred to the intermediate transfer belt 30 by the image forming unit 10Y. The toner images of the respective colors are transferred so as to overlap the toner images.

  The paper P is taken out from the paper container T by the take-out roll 81. The paper P is transported along the paper transport path R in the direction of arrow C toward the secondary transfer device 50 by the transport roll 83 and the registration roll 84. The registration roll 84 sends the paper P to the secondary transfer device 50 based on the timing at which the toner image is transferred onto the intermediate transfer belt 30. The secondary transfer device 50 transfers the toner image on the intermediate transfer belt 30 to the paper P by applying a transfer potential between the intermediate transfer belt 30 and the paper P. The sheet P on which the toner image is transferred is conveyed from the secondary transfer unit 50 to the fixing device 60, and the toner image transferred onto the sheet is fixed. In this way, an image is formed on the paper. The sheet on which the image is formed is discharged to the outside of the image forming apparatus 1 by the discharge roll 86. The toner remaining on the intermediate transfer belt 30 after the transfer by the secondary transfer device 50 is removed by the belt cleaner 70.

[Developer]
FIG. 2 is a plan view of the developing device shown in FIG. FIG. 3 is a longitudinal sectional view of the developing device. Although the developing device 14Y for yellow is shown in the drawing, the developing devices 14M to 14K for other colors also have the same structure as the developing device 14Y.

  The developing device 14Y includes a developer container 140, a developing roll 141, a first stirring and conveying member 142, a second stirring and conveying member 143, a layer regulating member 147, and an interference member 148. FIG. 2 shows a state where the cover of the developer container 140 is removed.

  The developer container 140 contains a developer. The interior of the developer container 140 is partitioned into a first storage chamber 140a and a second storage chamber 140b by a partition wall 1401. The first storage chamber 140a is adjacent to the developing roll 141, and the second storage chamber 140b is disposed on the opposite side of the developing roll 141 with the first storage chamber 140a interposed therebetween.

  The first agitation transport member 142 is disposed in the first storage chamber 140a, and the second agitation transport member 143 is disposed in the second storage chamber 140b. The two agitating / conveying members 142 and 143 extend in the front-rear direction DE in the image forming apparatus 1, that is, in the extending direction in which the developing roll 141 extends. The agitating / conveying members 142 and 143 include rotating shafts 1421 and 1431 extending in parallel with the developing roll 141 and spiral spiral blades 1422 and 1432 provided around the rotating shafts 1421 and 1431, respectively. Each of the stirring and conveying members 142 and 143 is supported by the developer container 140 so that both end portions of the rotating shafts 1421 and 1431 are rotatable. The rotary shafts 1421 and 1431 are connected to a gear 146 that transmits a driving force from a motor (not shown). The developing roll 141 and the two agitating / conveying members 142 and 143 are driven by a motor (not shown) to rotate.

  The first agitating and conveying member 142 conveys the developer in the first storage chamber 140a in the first conveying direction D by rotating around the axis of the rotating shaft 1421. The second stirring / conveying member 143 rotates around the axis of the rotation shaft 1431 to convey the developer in the second storage chamber 140b in the second conveying direction E opposite to the first conveying direction. The developer in the developer container 140 circulates through the first storage chamber 140a and the second storage chamber 140b via connection ports 1401a and 1401b provided at both ends of the partition wall 1401.

  The developing roll 141 conveys the developer from the developer container 140 to the surface of the photoreceptor 11Y (see FIG. 1). The developing roll 141 has a cylindrical shape, and a magnet 1411 is disposed inside the developing roll 141. The magnet 1411 is fixed to the developer container 140, and has a pickup magnetic pole for attracting the magnetic carrier to which the toner particles are adhered to the developing roll 141, and a magnetic pole for causing the developer to stand up in the development area. The developing roll 141 corresponds to an example of the rotating transport body referred to in the present invention.

  The developing roll 141 conveys the developer to the surface of the photoreceptor 11Y by rotating while holding the developer on the surface. A direction in which the developer is transported toward the surface of the photoconductor 11Y is defined as a transport direction F. The toner contained in the developer conveyed to the surface of the photoconductor 11Y adheres to the portion of the surface of the photoconductor 11Y that has been irradiated with light. The toner or magnetic carrier that has not adhered to the photoreceptor 11Y is held by the developing roll 141 and returns to the first storage chamber 140a again. An amount of new toner corresponding to the amount of toner consumed by development is supplied from the toner cartridge 18Y (see FIG. 1) to the image material container 140.

  FIG. 4 is a view of the layer regulating member and the interference member as viewed from above the developing device. FIG. 5 is a sectional view showing portions of the layer regulating member and the interference member. The description will be continued with reference to FIGS.

  The layer regulating member 147 is a plate-like member disposed upstream of the photoreceptor 11Y in the transport direction F of the developing roller 141. The layer regulating member 147 is disposed above the developing roll 141 and extends in a direction intersecting with the transport direction F. The layer regulating member 147 is arranged with a gap G1 between the surface of the developing roll 141. The developer conveyed on the surface of the developing roll 141 from the developer container 140 passes through the gap between the layer regulating member 147. The layer regulating member 147 equalizes the thickness of the developer layer conveyed to the photoreceptor 11Y by the developing roll 141. Further, the developer is agitated when passing under the layer regulating member 147, and the charge amount of the toner and the magnetic carrier increases. That is, the layer regulating member 147 increases the charge amount of the developer immediately before being supplied to the photoreceptor 11Y. The smaller the gap between the layer regulating member 147 and the developing roll 141 is set, the more the charge amount of the developer increases.

  The interference member 148 is a protrusion that is disposed above the developing roll 141 and extends downward toward the surface of the developing roll 141. The interference member 148 is disposed upstream of the layer regulating member 147 in the transport direction F, and is arranged with an interval in a direction intersecting with the developer flow. More specifically, the interference members 148 are arranged in the front-rear direction DE intersecting the transport direction F, that is, in the extending direction in which the developing roll 141 extends, and are transported in the transport direction F so as to be two-dimensionally arranged as a whole. There are also a plurality of them. In the interference member 148 shown in FIGS. 4 and 5, two rows of comb-like protrusions arranged in the front-rear direction DE are arranged in the transport direction F. The base of the layer regulating member 147 and the interference member 148 is joined to the top plate 149 and integrated.

  A gap G <b> 2 is provided between the interference member 148 and the developing roll 141. The gap G2 is such that the rotating developing roll 141 and the interference member 148 are not in contact with each other, and is smaller than the gap G1 between the layer regulating member 147 and the developing roll 141.

  In the developing device 14Y of the present embodiment, when the developing roll 141 rotates, the developer on the developing roll 141 is transported in the transport direction F. The interference member 148 interferes with the developer flow. The developer is stirred by moving in the front-rear direction DE so as to sew between the interference members 148. As a result, the charge amount of the developer toner and the magnetic carrier increases as compared with the case where the interference member 148 is not provided. Further, since the developer passes so as to sew between the interference members 148 arranged with a space therebetween, the force that the developer receives when passing is smaller than that of the layer regulating member 147.

  In the developing device 14 </ b> Y of the present embodiment, the amount of charge by the layer regulating member 147 is reduced by the amount of increase in the developer charge amount by the interference member 148. Specifically, the gap G1 between the layer regulating member 147 and the developing roll 141 is set to be larger than assumed when there is no interference member 148.

  On the upstream side in the transport direction F of the layer regulating member 147, a developer that cannot pass under the layer regulating member 147 accumulates, and the developer receives a strong pressure when passing under the layer regulating member 147. The smaller the gap between the layer regulating member 147 and the developing roll 141, the higher the pressure received by the developer, and the more easily the deterioration of the particle surface is scraped or the particle is broken or deformed.

  In the developing device 14Y of the present embodiment, the gap G1 between the layer regulating member 147 and the developing roll 141 is set to be larger than assumed when there is no interference member 148. Therefore, the deterioration of the developer is suppressed while maintaining the charge amount of the developer.

  In the above-described embodiment, as an example of the interference member according to the present invention, the interference member 148 in which two rows of comb-shaped protrusions are arranged in the transport direction F is shown. However, the present invention is not limited to this, and the interference member may be, for example, one in which only one row of comb-shaped protrusions is arranged, or may be one in which three or more rows are arranged. . The interference members may be arranged obliquely with respect to the front-rear direction.

  Further, in the above-described embodiment, a rotating developing roll is shown as an example of the rotating conveyance body referred to in the present invention. However, the rotary conveyance body referred to in the present invention is not limited to this, and may be, for example, an endless belt.

  In the embodiment described above, a tandem color printer is shown as an example of the image forming apparatus according to the present invention. However, the image forming apparatus referred to in the present invention is not limited to this, and may be a monochrome printer that does not have an intermediate transfer belt, for example.

  In the embodiment described above, a printer is shown as an example of the image forming apparatus according to the present invention. However, the image forming apparatus according to the present invention is not limited to a printer, and may be, for example, a copying machine or a facsimile that forms an image based on data read by the image reading apparatus.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 11Y Photoconductor 14Y Developing apparatus 140 Developer container 141 Developing roll 147 Layer control member 148 Interference member

Claims (3)

A rotating conveyance body that is arranged adjacent to the developing object and rotates while holding the developer on the surface to convey the developer to the surface of the developing object;
Layer regulation that regulates the layer thickness of the developer disposed with a gap between the surface and the upstream side in the transport direction in which the developer is transported by rotation of the rotating transport body. Members,
Arranged in a first direction that is disposed upstream of the layer regulating member in the conveying direction and extends toward the surface of the rotary conveying member and intersects the developer flow flowing toward the layer regulating member. And a plurality of interference members that interfere with the flow of the developer.   The interference members are arranged in the first direction, and a plurality of the interference members are also provided in the developer flow direction so as to be two-dimensionally arranged in a zigzag manner as a whole. Item 2. The developing device according to Item 1. A developing object on which an electrostatic latent image is formed and the electrostatic latent image is developed with a developer;
A developing device for developing the object to be developed with a developer;
The developing device is
A rotating and conveying body that is arranged adjacent to the object to be developed and conveys the developer to the surface of the object to be developed by rotating while holding the developer on the surface;
A plate shape that regulates the layer thickness of the developer disposed with a gap between the surface and the upstream side in the transport direction in which the developer is transported by the rotation of the rotating transport body. A layer regulating member of
Arranged in a first direction that is disposed upstream of the layer regulating member in the conveying direction and extends toward the surface of the rotary conveying member and intersects the developer flow flowing toward the layer regulating member. An image forming apparatus comprising: a plurality of interference members that interfere with the flow of the developer.

Images