JP2007041209A - Developing unit, process cartridge, and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing unit that can adjust the amount of the developer to be supplied and attains simple mechanism and space-saving, and also provide a process cartridge and an image forming device thereof. <P>SOLUTION: This developing unit 4 has a developer carrier 22, a container 21 to store the developer, developer supply sections 26, 27 which agitate the toner and developer and supply the developer in the container to the developer carrier, a developer regulator 23 to set thickness of the developer on the carrier to be suitable for developing, a preset case 29 to store the unused initial developer to be supplied to the developer container 21, a sealant 31 which is attached to seal the opening provided on the preset case 29 at its initial developer supplying side and is removed in the length direction of the developer carrier when starting to be used by the developing unit 4, and at least one electromagnet 32 in the preset case 29. The initial developer attracted by the electromagnet 32 can be removed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a developing device that supplies toner into a developer container that contains a developer, a process cartridge including the developing device, and an image forming apparatus including the developing device.

  In a developing device that contains a developer containing toner and a carrier, if the image is continuously output, the toner in the developer is consumed in the developing area, and the toner is supplied in the shortage. At this time, the replenished toner and the developer are mixed (see, for example, Patent Documents 1 to 6).

Japanese Patent Laid-Open No. 10-63074 Japanese Patent Application Laid-Open No. 7-104569 Japanese Unexamined Patent Publication No. 7-134486 JP-A-6-242683 Japanese Patent Laid-Open No. 9-185242 JP 2003-5516 A

  By the way, when the mixing process of the replenished toner and the developer is repeated, the toner additive adheres to the surface of the carrier, and the toner charge amount is reduced, so that the supply of the toner is suppressed and the toner density is lowered. May be invited. As a result, the bulk of the developer is reduced, and there is a risk of density unevenness due to insufficient pumping.

  Although it is possible to increase the initial developer in anticipation of a decrease in the toner concentration over time, if the developer concentration in the developer container exceeds the allowable amount of the developer due to fluctuations in the toner concentration due to the environment, the developer dispersion This may cause a defect, fail to ensure a sufficient amount of toner charge, and may cause toner scattering or background contamination.

  The present invention has been made by paying attention to the above circumstances, and the object of the present invention is to adjust the amount of developer to be added and to simplify the mechanical mechanism and to save space. To provide a developing device, a process cartridge, and an image forming apparatus.

  In order to solve the above-mentioned problem, the invention described in claim 1 is a developer carrying member for developing a latent image formed on a latent image carrying member by conveying a developer containing toner and a carrier, A developer supply for supplying a developer container for supplying the developer carrier to the developer carrier, agitating the replenished toner and the developer, and supplying the developer in the developer container to the developer carrier. A member, a developer regulating member that sets the developer on the developer carrying member to a thickness suitable for development, a preset case that accommodates an unused initial developer that is put into the developer container, and the preset case In a developing device comprising: an initial developer charging opening provided on the developer container side; and a seal member detachably attached in a longitudinal direction of the developer carrier when starting to use the developing device. Preset At least one electromagnet in the scan includes, characterized by being configured to releasably initial developer adsorbed by the electromagnet.

  The invention described in claim 2 is the electromagnet according to the invention described in claim 1, wherein the initial developer accommodated in the preset case removes the seal member at the start of use of the developing device. The initial developer that is not affected by the electromagnet is put into the developing container, and the initial developer that is affected by the electromagnet remains in the preset case without being put into the developing container.

  Further, in the invention described in claim 3, in the invention described in claim 1 or 2, when the volume of the developer in the developer container is reduced due to a decrease in toner concentration, the developer is passed through the electromagnet. The initial developer adsorbed on the electromagnet is gradually released by gradually decreasing the strength of electricity.

  The invention described in claim 4 is the invention according to any one of claims 1 to 3, wherein the electromagnet and the initial developer are not directly adsorbed on the electromagnet. And a magnetically permeable member disposed between the two.

  The invention described in claim 5 is characterized in that, in the invention described in any one of claims 1 to 4, the preset case has one wall and two rooms. To do.

  The invention described in claim 6 is the invention described in claim 5, wherein the electromagnet is provided in one room of the preset case, and only the carrier, not the initial developer, is accommodated in the room. It is characterized by doing.

  A process cartridge according to a seventh aspect is at least selected from the developing device according to any one of the first to sixth aspects, a photosensitive member, a charging means, a developing means, and a cleaning means. One means is integrally supported and is detachable from the main body of the image forming apparatus.

  An image forming apparatus according to an eighth aspect includes the developing device according to any one of the first to sixth aspects.

  An image forming apparatus according to a ninth aspect includes the process cartridge according to the seventh aspect.

  According to the present invention, it is possible to adjust the amount of developer to be charged and to simplify the mechanical mechanism and to save space.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a plurality of photoconductors arranged side by side using an intermediate transfer belt, each having a developing device, and forming a single color toner image on each photoconductor, and sequentially transferring these single color toner images onto a sheet. This is an image forming portion of a so-called tandem type color copier that records a composite color image.

  The configuration of the image forming process will be briefly described with reference to FIG. In the image forming apparatus, as shown in FIG. 1, the photosensitive drums 1a to 1d, which are drum-shaped latent image carriers on which electrostatic latent images are formed on the outer peripheral surface, and the outer peripheral surfaces of the photosensitive drums 1a to 1d Charging rollers 2a to 2d for charging to the surface, light emitting elements 3a to 3d for forming an electrostatic latent image on the outer peripheral surface charged to a specified potential by exposure, and converting the electrostatic latent image into a visible image of toner. Development devices 4a to 4d, an intermediate transfer belt 5 that temporarily transfers the visible image formed on the outer peripheral surface, a paper transfer belt 7 that transfers the visible image of the intermediate transfer belt 5 to a transfer paper, and a fixing device 8. I have.

  In this embodiment, the photosensitive members 1a to 1d, the charging units 2a to 2d, the developing units 4a to 4d, and the cleaning units 9a to 9d are integrally supported, and are detachable from the main body of the image forming apparatus. Cartridge.

  Next, the operation of the entire image forming apparatus will be described with reference to FIG. In the image forming apparatus, the photosensitive drums 1a to 1d, which are latent image carriers provided rotatably, are uniformly charged by the charging rollers 2a to 2d, and are exposed by the light emitting elements 3a to 3d to be electrostatic latent images. Form. The electrostatic latent image is visualized as a toner image by applying non-magnetic toner by the developing devices 4a to 4d.

  Next, the visible image is temporarily transferred to the intermediate transfer belt 5 by the intermediate transfer belt means 12a to 12d and transferred to the transfer paper conveyed through the pair of registration rollers 6, and the visible image of the intermediate transfer belt 5 is transferred by the paper transfer belt 7. Is transcribed. The visible image transferred to the transfer paper is conveyed by a paper transfer belt, and the fixing device 8 performs a fixing process on the visible image to obtain a permanent image.

  Transfer residual toner on the photosensitive drum 1 is removed by the cleaning devices 9a to 9d. The residual toner on the intermediate transfer belt is removed by the intermediate transfer cleaning blade 12. The new toner filled in the toner bottle is replenished to the toner hoppers 11a to 11d on the back side of the machine body by the toner replenishing devices 10a to 10d. The toner stored in the toner hopper is supplied to the developing device 4 from the inside of the hopper when the toner concentration detecting means in the developing device determines that the toner concentration in the developing device is low.

  FIG. 2 is a schematic cross-sectional view showing a schematic configuration of the developing device 4. As shown in FIG. 2, the developing device 4 is disposed to face the photosensitive drum 1 that is a latent image carrier, and serves as a developer carrier that carries the developer container 21 and the developer in the developer container 21. A developing sleeve 22 and a blade 23 as a developer pre-formed member for regulating the head height of the developer carried on the developing sleeve 22 are provided.

  The developing container 21 is divided into a developing chamber 24 positioned closer to the developing roller partitioned in the vertical direction and a stirring chamber 25 positioned farther from the developing roller. In the developing chamber 24 and the stirring chamber 25, a developer (two-component developer) containing a non-magnetic toner (hereinafter referred to as toner) and a magnetic carrier (hereinafter referred to as carrier) is accommodated. The developer in the stirring chamber 25 is circulated.

  In the developing chamber 24 and the agitating chamber 25, a rotatable developer supply for agitating and conveying the developer and toner in the developer container and supplying the developer to the developing roller in parallel with the developing roller, respectively. The developer agitating / conveying means 26 (hereinafter referred to as a first screw) as a member and the developer agitating / conveying in a direction parallel to the first screw 26 and facing the first, to circulate the developer. A second developer agitating / conveying means 27 (hereinafter referred to as a second screw) is disposed as a rotatable developer supply member.

  The developing sleeve 22 is made of a non-magnetic material, and a magnet 28 that generates a magnetic field is fixedly disposed therein. The developing sleeve 22 incorporating the magnet 28 carries and transports a layer of the two-component developer whose layer thickness is regulated by the blade 23 to the developing area, and supplies toner to the photosensitive drum 1 in the developing area facing the photosensitive drum 1. The electrostatic latent image formed on the photosensitive drum 1 is developed.

  Further, the developing device 4 is provided with a preset case 29 for storing an unused initial developer 30 to be put into the developing container 21, and the initial case provided on the developing container side of the preset case 29 at the start of use of the developing device 4. The initial developer 30 is charged into the developing container 21 by removing the seal member 31 sealing the developer charging opening in the longitudinal direction of the developing device 4.

  Next, a schematic configuration of the preset case 29 provided with the characteristic electromagnet 32 of the present embodiment will be briefly described with reference to FIGS. 3 and 4. As shown in FIGS. 3 and 4, an electromagnet 32 is disposed on the end of the preset case 29 above the stirring chamber 25 in FIG. 2.

  With such a configuration, the initial developer 30 accommodated in the preset case 29 can be developed by removing the seal member 31 at the start of use of the developing device 4 so that the initial developer 41 that is not affected by the electromagnet 32 is developed. The initial developer 42 charged into the container 21 and affected by the electromagnet 32 remains in the preset case 29 without being charged into the developing container 21. Then, when the volume of the developer in the developing container 21 is reduced due to the decrease in the toner concentration over time, the strength of electricity flowing through the electromagnet 32 is gradually reduced to be attracted to the electromagnet 32. By gradually detaching the initial developer 42, it is possible to suppress the occurrence of density unevenness due to insufficient pumping caused by a decrease in the volume of the developer over time.

  Another embodiment will be described with reference to FIGS. 5 and 6. A partition plate 33 is provided in the preset case 29, an electromagnet 32 is provided in one room, the carrier 34 is accommodated only in the room, not the initial developer 30, and the initial developer 30 is not provided in the other room without the electromagnet 32. , The initial developer 30 and the carrier 34 are not mixed before the use of the developing device 4 is started. Further, by removing the seal member 31 at the start of use of the developing device 4, the initial developer 30 in the room without the electromagnet 32 is introduced into the developing container 21, and the carrier 34 in the room in which the electromagnet 32 is provided is loaded into the developing container 21. It remains in the preset case 29 without being inserted.

  As described above, in the present embodiment, at least one electromagnet 32 is provided in the preset case 29 and the initial developer attracted by the electromagnet 32 is configured to be detachable. Is attracted by the electromagnet 32 and can be detached when it is desired to be put in. In particular, by using the electromagnet 32 as the magnetic field generating means, it is possible to adjust the amount of developer to be supplied with the strength of the current, and the mechanical mechanism is simpler than that of the permanent magnet, which is advantageous in terms of space. It is done.

  In the present embodiment, the initial developer stored in the preset case 29 is removed from the developing container 4 when the developing device 4 is started, so that the initial developer that is not affected by the electromagnet 32 is put into the developing container 21. The initial developer affected by the electromagnet 32 remains in the preset case 29 without being charged into the developing container 21. Therefore, it is possible to add a part of the initial developer over time rather than at the start of use of the developing device 4.

  In the present embodiment, when the volume of the developer in the developing container 21 is reduced due to a decrease in the toner concentration, the strength of electricity flowing through the electromagnet 32 is gradually reduced to attract the electromagnet 32. Since the initial developer is gradually removed, density irregularities that occur over time can be increased by increasing the volume of the developer by suppressing the occurrence of density irregularities due to insufficient pumping. Is possible. Further, it is possible to finely adjust the amount of the initial developer to be charged depending on the strength of the current.

  In the present embodiment, since a magnetically permeable member is provided between the electromagnet 32 and the initial developer so that the initial developer is not directly adsorbed to the electromagnet 32, the initial developer is extended to the inside of the electromagnet 32. It is possible to prevent the initial developer from being completely removed.

  Further, in the present embodiment, the preset case 29 has one wall and two rooms, so that it is possible to accommodate the initial developer and the carrier, and to prevent mixing. Is possible.

  In the present embodiment, the electromagnet 32 is provided in one room of the preset case 29, and only the carrier is accommodated in the room, not the initial developer. Therefore, the initial development is started at the start of use of the developing device 4. It is possible to introduce the agent and to introduce the carrier over time.

1 is a schematic configuration diagram of an image forming portion of a tandem type color copying machine including an embodiment of the present invention. It is a schematic block diagram of the developing device of the copying machine shown in FIG. It is a schematic block diagram of the preset case provided with the electromagnet. It is a schematic block diagram of the preset case provided with the electromagnet. It is another schematic block diagram of the preset case provided with the electromagnet. It is another schematic block diagram of the preset case provided with the electromagnet.

Explanation of symbols

1a to 1d Photosensitive drum (latent image carrier)
21 Developing container 22 Developing sleeve (Developer carrier)
23 Blade (Developer regulating member)
24 Developing chamber 25 Stirring chamber 26, 27 Screw (developer supply member)
29 Preset case 31 Seal member 32 Electromagnet

Claims (9)

A developer carrying member for developing a latent image formed on the latent image carrying member by conveying a developer containing toner and a carrier;
A developer container for containing a developer to be supplied to the developer carrier;
A developer supply member that stirs the replenished toner and developer, and supplies the developer in the developer container to the developer carrier;
A developer regulating member for setting the developer on the developer carrier to a thickness suitable for development;
A preset case for storing an unused initial developer to be put into the developer container;
Development provided with a seal member that seals an opening for initial developer input provided on the developer container side of the preset case and is detachably attached in the longitudinal direction of the developer carrier when starting to use the developing device In the device
A developing device comprising at least one electromagnet in the preset case, wherein the initial developer adsorbed by the electromagnet is detachable.   The initial developer accommodated in the preset case is removed from the seal member at the start of use of the developing device, so that the initial developer that is not affected by the electromagnet is put into the developer container and is affected by the electromagnet. The developing device according to claim 1, wherein the initial developer remains in the preset case without being charged into the developing container. When the volume of the developer in the developer container is reduced due to a decrease in toner concentration, the initial developer adsorbed on the electromagnet is gradually reduced by gradually decreasing the strength of the electricity flowing through the electromagnet. The developing device according to claim 1, wherein the developing device is separated from the developing device.   4. A magnetically permeable member provided between the electromagnet and the initial developer so as not to attract the initial developer directly to the electromagnet. The developing device according to item 1.   The developing device according to claim 1, wherein the preset case has one wall and two rooms.   6. The developing device according to claim 5, wherein the electromagnet is provided in one room of the preset case, and only the carrier is accommodated in the room, not the initial developer.   An image forming apparatus that integrally supports the developing device according to any one of claims 1 to 6, the photosensitive member, and at least one unit selected from a charging unit, a developing unit, and a cleaning unit. A process cartridge which is detachable from the main body.   An image forming apparatus comprising the developing device according to claim 1. An image forming apparatus comprising the process cartridge according to claim 7.

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