JP5962517B2 - Developing device and image forming apparatus - Google Patents

Description

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

  In an image forming apparatus such as a copying machine or a printer, a developing device that develops an electrostatic latent image formed on a photoreceptor is used. In this developing device, a developing roll is provided facing the photoconductor. In this developing roll, a two-component developer (hereinafter referred to as a developer) containing a magnetic carrier, a colored resin toner, and the like is accommodated and conveyed by being attracted by a magnetic pole. The toner conveyed by the developing roll is selectively attached to a region where the developing roll and the photosensitive member face each other, and a toner image is formed on the photosensitive member.

Further, in the developing device, a trimmer is disposed at a position facing the outer peripheral surface of the developing roll, and the formation of the developer layer held on the developing roll is restricted. For example, this trimmer regulates the height of the developer layer fed to the developing roll to adjust the layer formation (see Patent Document 1).
In addition, a developing device provided with a reflux port provided with a main trimmer member and a sub trimmer member to reduce the influence of foreign matter mixed in the developer and return the developer regulated by the sub trimmer member to the upstream side. It is known (see, for example, Patent Document 2).

JP 62-156680 A JP-A-4-249276

  In the trimmer that regulates the developer held on the developing roll, trimmer clogging may occur due to fluctuations in the supply amount of the developer, excessive pickup amount, and the like, and the deterioration of the developer may be accelerated. Further, it is difficult to make the developer concentration uniform only by returning the regulated developer to the upstream side.

  The present invention relates to a developing device capable of suppressing developer aggregation in a trimmer that regulates the developer held on a developing roll, deterioration due to stress, and the like, and an image forming apparatus using the same. The purpose is to provide.

  The invention described in claim 1 includes a housing for accommodating the developer, a pick-up pole for picking up the developer, and a developing roll for developing the electrostatic latent image on the photosensitive member by the developer while rotating the electrostatic latent image. A stirring auger provided in the housing for stirring the developer and the replenished toner, and a developer provided in the housing and supplied from the stirring auger is supplied to the developing roll. Provided between the supply auger, the agitation auger and the supply auger, facing the outer peripheral surface of the developing roll, and a partition plate for partitioning the first auger, the first auger, A layer thickness of the picked-up developer that has a gap, scrapes off a part of the developer picked up by the pick-up pole, and flies in the direction of the stirring auger A first trimmer to be regulated and a second gap which is arranged downstream of the first trimmer and which is narrower than the first gap, further regulates the layer thickness of the developer regulated by the first trimmer. A developing device having two trimmers.

  According to a second aspect of the present invention, the first trimmer is disposed such that a front end thereof faces the tangent line of the outer periphery of the developing roll, and a rear end is disposed between the tangent line and a horizontal line that is in contact with the upper end of the partition plate. The developing device according to claim 1, wherein the developing device is provided.

  According to a third aspect of the present invention, in the developing device according to the second aspect, the rear end is formed to extend above the partition plate.

  The invention according to claim 4 is formed so as to draw a gentle curve from the front end to the rear end, and a part of the developer scraped off moves along the gentle curve, The developing device according to claim 2, wherein the developing device flies to a stirring auger.

The invention according to claim 5 is the developing device according to any one of claims 1 to 4, wherein the first trimmer is formed of a thin film-like member.

  A sixth aspect of the present invention is an image forming apparatus comprising the developing device according to any one of the first to fifth aspects, wherein an image is formed on a supplied recording medium. .

According to the first aspect of the present invention, a developing device can be obtained in which the layer formation of the developing roll is made uniform and stable and the concentration of the developer can be made uniform as compared with the case where this configuration is not provided.
According to the second aspect of the present invention, a developing device capable of making the developer concentration uniform can be obtained.
According to the third aspect of the present invention, the developer in the supply auger having a reduced toner concentration is mixed with the developer having a high toner concentration.
According to the fourth aspect of the present invention, the developer having a low toner concentration can be more effectively jumped to the stirring auger.
According to the fifth aspect of the present invention, the developer can be caused to fly with a simple configuration.
According to the image forming apparatus of the sixth aspect, compared with the case where the developing apparatus according to any one of the first to third aspects is not provided, the layer formation of the developing roll is uniform and stable. The quality of image formation on the recording medium can be improved, and stable image formation can be provided.

1 is a schematic configuration diagram illustrating an image forming apparatus using a developing device according to an embodiment. 1 is a schematic diagram illustrating a developing device according to an embodiment.

(Embodiment)
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of an image forming apparatus using the developing device of the present invention. The image forming apparatus 1 according to the embodiment includes a control unit 2, a photoconductor 10, a charging unit 20, an exposure unit 30, a developing device 40, a transfer unit 50, a fixing unit 60, a cleaning unit 70, and a paper storage unit 80. An image is formed on paper P, which is a recording medium, based on the supplied image information.

The control unit 2 is a CPU (Central
An arithmetic device such as a processing unit) and a memory are provided, and the operation of each component of the image forming apparatus 1 is controlled.

  The photosensitive member 10 is a cylindrical rotating member having a photosensitive layer formed of an organic photosensitive material for holding an image and rotating in the direction of the arrow shown in FIG.

  The charging unit 20 applies a predetermined charging voltage using a charging roll that rotates in contact with the surface of the photoreceptor 10. The charging unit 20 includes a contact charging method in which the photosensitive member 10 is charged by using a brush or the like, or a non-contact charging method in which the photosensitive member 10 is charged using corona discharge.

  The exposure unit 30 irradiates the surface of the photoconductor 10 charged by the charging unit 20 with light corresponding to image data to form an electrostatic latent image having a latent image potential based on a potential difference. The electrostatic latent image moves to a position where the developing device 40 is disposed as the photoconductor 10 rotates.

  The developing device 40 has a rotating developing roll 42 provided in the opening of the housing 41, and the toner adsorbed on the developing roll 42 is transferred to the photoconductor 10. This toner moves to the surface of the photoconductor 10 due to a potential difference from the electrostatic latent image formed on the photoconductor 10. In this way, a toner image is formed on the photoconductor 10, and this toner image moves to the transfer unit 50 as the photoconductor 10 rotates.

  A stirring auger 43 and a supply auger 44 are provided inside the housing 41 of the developing device 40, and these are partitioned by a partition plate 45. Further, a first trimmer 46 and a second trimmer 47 are disposed at a position facing the outer peripheral surface of the developing roll 42. A detailed description of the developing device 40 will be described later.

  The transfer unit 50 transfers the toner image formed on the photoconductor 10 onto the paper P conveyed by the conveyance roll 91. The sheet P on which the toner image is transferred is conveyed to the fixing unit 60 by the conveyance roll 91.

  The fixing unit 60 includes a heating roll 61 having a heat source and a pressure roll 62 provided to face the heating roll 61, and fixes an unfixed toner image on the paper P by heating and pressing. . The paper P on which the toner image is fixed by the fixing unit 60 is transported and stored by the transport roll 91.

  The cleaning unit 70 removes the toner remaining on the surface of the photoconductor 10 after the toner image is transferred to the paper P. In the paper storage unit 80, a plurality of papers P are stored. The paper P is taken out from the paper storage unit 80 by the paper feed roll 90 and conveyed to the transfer unit 50 by the conveyance roll 91.

  Next, the developing device 40 of the embodiment will be described. FIG. 2 shows the configuration of the developing device 40. As shown in FIG. 2, the developing device 40 includes a housing 41, a developing roll 42 having a pickup electrode 42 a, a stirring auger 43, a supply auger 44, a partition plate 45, a first trimmer 46, and a second trimmer 47.

  The housing 41 has an opening at a portion facing the rotating photoreceptor 10 that holds and rotates the electrostatic latent image, and is formed to accommodate the developer D.

  The developing roll 42 is provided in a portion where the housing 41 is opened. The developing roll 42 is disposed so as to hold the developer D and develop the electrostatic latent image on the photoreceptor 10.

  The pickup pole 42 a is, for example, a magnet that is fixedly provided inside the developing roll 42 so as to face the supply auger 44. The developer D supplied from the supply auger 44 is attracted to the surface of the developing roll 42 by the magnetic force of the pickup pole 42a.

  The developer D adsorbed on the pickup pole 42a becomes, for example, in a state where the developer D containing toner is spiked at a position of a magnetic force line L that is perpendicular to the surface of the developing roll 42 of the pickup pole 42a. A magnetic brush is formed. The developer D thus formed is held on the developing roll 42 and conveyed along with the rotation of the developing roll 42.

  The stirring auger 43 is provided inside the housing 41. The stirring auger 43 is formed so as to stir the developer D and the toner replenished to the developer D, for example.

  The supply auger 44 is provided inside the housing 41. The supply auger 44 is formed so as to supply the developer D supplied from the stirring auger 43 to the developing roll 42.

  The partition plate 45 is provided between the stirring auger 43 and the supply auger 44, and is arranged so as to partition them. That is, with the partition plate 45 as a partition, the stirring auger 43 and the supply auger 44 supply the developer D to the developing roll 42 while circulating the developer D.

  The first trimmer 46 is provided so as to face the outer peripheral surface of the developing roll 42, and is disposed immediately downstream of the pickup electrode 42a. The trimmer gap of the first trimmer 46 is a gap G1 that is a predetermined first gap. That is, the gap G1 is provided on the downstream side of the magnetic field lines L so as to regulate the magnetic brush.

  The first trimmer 46 sets the developer D picked up by the pickup electrode 42a as the first layer developer D1 that is regulated so as to be held by the developing roll 42. Further, the first trimmer scrapes off the developer D, which is not regulated because it does not become the first layer developer D1, so as to fly in the direction of the stirring auger 43 from the developing roll 42, thereby forming the flying developer D 2.

  The first trimmer 46 has a front end 46 a facing the tangent line T on the outer periphery of the developing roll 42, and a rear end 46 b extending between the tangent line T and the horizontal line H in contact with the upper end of the partition plate 45 so as to extend above the partition plate 45. Is formed. The first trimmer 46 is formed of a film member that is a thin film member.

  This film member is formed so as to draw a gentle curve from the front end 46a to the rear end 46b. The flying developer D2 flies toward the stirring auger 43 over the partition plate 45 along the gentle curve of the first trimmer 46 thus formed.

  The second trimmer 47 is disposed on the downstream side of the first trimmer 46. The trimmer gap of the second trimmer 47 is a gap G2 that is a second gap narrower than the gap G1 of the first trimmer 46.

  The second trimmer 47 regulates the first layer developer D1 by having the gap G2 narrower than the gap G1 in this way. That is, the second trimmer 47 regulates the first layer developer D1 transported from the first trimmer 46 by the rotation of the developing roll 42 to be the second layer developer D3. The second layer developer D3 is held on the developing roll 42 and developed on the photoreceptor 10.

  The above is the description of the developing device 40 of the embodiment and the image forming apparatus 1 using the developing device. According to this embodiment, by providing the first trimmer 46 and the second trimmer 47, the developer from the supply auger 44 is surely picked up. Further, with such a configuration, the retention of the developer in the second trimmer 47 is reduced, and the layer formation of the developing roll 42 becomes stable.

  Further, according to the embodiment, the flying developer D2 scraped off by the first trimmer 46 is configured to fly to the stirring auger 43 beyond the partition plate 45. That is, the flying developer D2 having a low toner concentration is mixed with the developer having a high toner concentration in the stirring auger 43, so that the entire developer D has a more uniform toner concentration.

  The image forming apparatus 1 using the developing device 40 having such a configuration can improve quality by preventing image quality defects and extending lifetime.

(Other embodiments)
The above is the description of the developing device 40 of the embodiment and the image forming apparatus 1 using the same, but the present invention is not limited to the above-described embodiment, and other embodiments are possible. Hereinafter, other embodiments will be described.

The shape and length of the first trimmer 46 of the embodiment are not limited to this as long as the flying developer D2 is allowed to fly to the stirring auger 43. For example, the rear end 46 b of the first trimmer 46 may be shorter than the length extending up above the partition plate 45.
The first trimmer 46 may not be a film member but may be formed of a rigid body such as a synthetic resin or a metal. Further, the shape from the front end 46a to the rear end 46b may not be a gentle curve. For example, as long as the flying developer D2 is configured to fly to the stirring auger 43, a linear shape may be used.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Control part 10 Photoconductor 20 Charging part 30 Exposure part 40 Developing apparatus 41 Case 42 Developing roll 42a Pickup electrode 43 Agitation auger 44 Supply auger 45 Partition plate 46 First trimmer 46a Front end 46b Rear end 47 Second trimmer 50 Transfer section 60 Fixing section 61 Heating roll 62 Pressure roll 70 Cleaning section 80 Paper storage section 90 Paper feed roll 91 Transport roll P Paper D Developer D1 First layer developer D2 Flying developer D3 Second layer developer L Magnetic field lines G1, G2 gap

Claims (6)

A housing for containing the developer;
A developing roll that has a pickup pole for picking up the developer, and that develops the electrostatic latent image on the photosensitive member by rotating with the developer;
A stirring auger provided in the housing for stirring the developer and the replenished toner;
A supply auger provided in the casing and supplying the developer supplied from the stirring auger to the developing roll;
A partition plate provided between the stirring auger and the supply auger, and partitioning them;
Opposed to the outer peripheral surface of the developing roll, disposed on the downstream side of the pickup electrode, having a first gap, scraping off a part of the developer picked up by the pickup electrode, A first trimmer that controls the layer thickness of the developer that has been picked up by flying toward the direction;
A second trimmer disposed downstream of the first trimmer, having a second gap narrower than the first gap, and further regulating the layer thickness of the developer regulated by the first trimmer. A developing device. The first trimmer is disposed such that a front end thereof is directed to a tangent line on an outer periphery of the developing roll, and a rear end is disposed between the tangent line and a horizontal line that is in contact with an upper end of the partition plate. Item 2. The developing device according to Item 1. The developing device according to claim 2, wherein the rear end is formed to extend above the partition plate. It is formed so as to draw a gentle curve from the front end to the rear end, and a part of the scraped off developer moves along the gentle curve and flies to the stirring auger. The developing device according to claim 2. The developing device according to any one of claims 1 to 4, wherein the first trimmer is formed of a thin film-like member. An image forming apparatus comprising the developing device according to claim 1, and forming an image on a supplied recording medium.

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