JP2008262023A - Developing cartridge and image forming cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing cartridge and an image forming cartridge capable of more surely preventing the leakage of a developer. <P>SOLUTION: The developing cartridge 7 is detachably attached to an image forming apparatus. A container 30 stores the developer containing magnetic materials. A developing roller 31 is attached inside the container 30 so that a part thereof may be exposed through an opening O formed in the container 30. Magnets 41 and 42 are detachably attached to the container 30 so that two kinds of magnetic poles may be alternately formed in the axial direction of the developing roller 31. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a developing cartridge and an image forming cartridge, and more particularly to a developing cartridge and an image forming cartridge for forming a toner image using a magnetic developer.

  A replaceable developing cartridge is attached to an image forming apparatus such as a printer or a copier. Such a developing cartridge is packaged and shipped after the developer is injected at the factory.

  However, the developing cartridge has a problem that the developer leaks from the gap between the developing roller and the container due to an impact during transportation. This will be described below with reference to FIG. FIG. 9 is a sectional structural view of the developing cartridge 100 in the direction perpendicular to the axial direction of the developing roller.

  A developing cartridge 100 shown in FIG. 9 includes a container 101 and a developing roller 102. The container 101 serves to store a developer. The developing roller 102 is rotatably attached to the container 101 and is attached so as to be exposed from the container 101 so as to be opposed to a photosensitive drum (not shown).

  In the developing cartridge 100 configured as described above, the developing roller 102 rotates in the direction of the arrow in FIG. 9 and supplies toner to the opposing photosensitive drum (not shown). The residual toner that has passed through the region facing the photosensitive drum is collected from the gap g between the container 101 and the developing roller 102. Therefore, the gap g between the container 101 and the developing roller 102 is wide enough to collect the residual toner sufficiently. When such a gap g exists, the developer stored in the container 101 leaks from the gap g due to an impact during transportation of the developing cartridge 100.

  Therefore, conventionally, magnets 103 and 104 are attached to the container 101 as shown in FIG. FIG. 10 is a cross-sectional structure diagram of the developing cartridge 100 in a direction perpendicular to the axial direction of the developing roller 102 with the magnets 103 and 104 attached. FIG. 11A is a front view of the magnets 103 and 104 attached to the container 101, and FIG. 11B is a side view of the magnets 103 and 104.

  As shown in FIG. 10, the magnets 103 and 104 are attached to the container 101 so that the developer containing the magnetic material is attracted to the inside of the wall surface to which the magnets 103 and 104 are attached by magnetic force. become. As a result, the developer is prevented from leaking from the gap g due to impact.

  By the way, as shown in FIG. 11A, the magnets 103 and 104 used in the conventional developing cartridge 100 have an N pole and an S pole extending in the axial direction of the developing roller 102, and the circumferential direction of the developing roller 102. And N poles and S poles were alternately arranged. Such magnets 103 and 104 could not sufficiently prevent the leakage of the developer due to the impact when the developing cartridge 100 is transported. This will be described below.

  In the magnet shown in FIG. 11A, the magnetic field is generated in the circumferential direction of the developing roller 102 and is not generated in the axial direction of the developing roller 102 as shown in FIG. Therefore, when the developing cartridge 100 is stood up, the developer is concentrated on the lower end due to gravity. Therefore, when the developing cartridge 100 falls down, the developer leaks from the end of the gap g due to an impact.

Note that a developing unit described in Patent Document 1 has been proposed as a means for preventing developer leakage with a magnet. However, in Patent Document 1, no countermeasure is taken against the developer leakage as described above.
JP-A-8-272207

  SUMMARY OF THE INVENTION An object of the present invention is to provide a developing cartridge and an image forming cartridge that can more reliably prevent developer leakage.

  The present invention relates to a developer cartridge that is detachably attached to an image forming apparatus, a container that stores a developer containing a magnetic material, and a container that is partially exposed through an opening formed in the container. And a magnet removably attached to the container so that two kinds of magnetic poles are alternately formed in the axial direction of the developing roller.

  The present invention relates to an image forming cartridge that is detachably attached to an image forming apparatus, a container that stores a developer containing a magnetic material, and a container that is partially exposed through an opening formed in the container. A developing roller mounted inside, a photosensitive member facing the developing roller through the opening, and two types of magnetic poles are formed alternately in the axial direction of the developing roller so as to be removable from the container. And an attached magnet.

  According to the present invention, since the magnet is attached to the container so that two types of magnetic poles (N pole and S pole) are alternately formed in the axial direction of the developing roller, a magnetic field is generated in the container in the axial direction. It becomes like this. The magnetic field generated in the axial direction restricts the developer containing the magnetic material from moving in the axial direction. Therefore, even if the cartridge is stood, the developer is prevented from concentrating on one end of the container. As a result, the developer is prevented from leaking from the container due to the cartridge falling.

  In the present invention, the magnet is a magnet formed so that two kinds of magnetic poles are alternately arranged in the axial direction of the developing roller, and may be arranged to be substantially parallel to the developing roller. . As a result, the developer in the container is attracted to the wall surface of the container in a state where movement in the axial direction of the developing roller is restricted.

  In the present invention, the magnet may be disposed so as to face the developing roller across the wall surface of the container. The developing roller is provided near the opening. Therefore, according to the present invention, the developer in the vicinity of the opening can be restricted from moving in the axial direction of the developing roller. As a result, the developer can be more effectively prevented from leaking from the container.

  In the present invention, the apparatus further includes a supply roller that is attached to the container and supplies the developer to the developing roller, and the magnet is disposed so as to face the supply roller across the wall surface of the container. Also good.

  In the present invention, the apparatus further includes a supply roller having a shaft made of a magnetic material and attached to the container and supplying the developer to the development roller, and the magnets are disposed at both ends of the supply roller. Also good. Thereby, the shaft of the supply roller is magnetized. As a result, the developer in the container is attracted to the supply roller.

  In this invention, the said magnet may be arrange | positioned so that the same magnetic pole may oppose on both sides of the said supply roller. Thereby, two magnetic poles are alternately formed on the shaft of the supply roller.

  In the present invention, the apparatus may further include a stirring roller that has a shaft made of a magnetic material and is attached in the container and stirs the developer, and the magnets may be disposed at both ends of the stirring roller. Thereby, the shaft of the stirring roller is magnetized. As a result, the developer in the container is attracted to the stirring roller.

  In this invention, the said magnet may be arrange | positioned so that the same magnetic pole may oppose on both sides of the said stirring roller. As a result, two magnetic poles are alternately formed on the shaft of the stirring roller.

(Configuration of image forming apparatus)
Hereinafter, a configuration of an image forming apparatus including a developing cartridge or an image forming cartridge according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an overall configuration of the image forming apparatus 1.

  An image forming apparatus 1 shown in FIG. 1 is an electrophotographic color printer, and synthesizes images of four colors (Y: yellow, M: magenta, C: cyan, K: black) in a so-called tandem system. It is composed. The image forming apparatus 1 has a function of receiving a print job and forming an image on a printing medium such as paper, and includes a printing unit 2, a paper feeding unit 14, a fixing device 19, and a paper discharge tray 20.

  The paper supply unit 14 serves to supply paper one by one, and includes a paper tray 15 and a paper supply roller 16. A plurality of types of sheets in a state before printing are stacked on the sheet tray 15. The paper feed roller 16 takes out the paper placed on the paper tray 15 one by one.

  The printing unit 2 serves as a toner image forming unit that forms a toner image on a sheet supplied from the sheet feeding unit 14, and includes an image forming station 21 (21 Y, 21 M, 21 C, 21 K), an exposure control unit 3, A primary transfer roller 8 (8Y, 8M, 8C, 8K), a transfer belt 10, a drive roller 11, a driven roller 12, a transfer roller 13, and a cleaning blade 17 are included. The image forming station 21 (21Y, 21M, 21C, 21K) includes a photosensitive drum 4 (4Y, 4M, 4C, 4K), a charger 5 (5Y, 5M, 5C, 5K), and an exposure device 6 (6Y, 6K). 6M, 6C, 6K), developing cartridge 7 (7Y, 7M, 7C, 7K) and cleaner 9 (9Y, 9M, 9C, 9K).

  The peripheral surface of the photosensitive drum 4 is charged by the charger 5. The exposure apparatus 6 irradiates the laser under the control of the exposure control unit 3. As a result, an electrostatic latent image is formed on the peripheral surface of the photosensitive drum 4. The developing roller of the developing cartridge 7 supplies toner to the photosensitive drum 4 on which the electrostatic latent image is formed, so that a toner image is formed on the peripheral surface of the photosensitive drum 4.

  The toner image is transferred to a transfer belt 10 that is stretched between a driving roller 11 and a driven roller 12. The toner image is transported to the transfer roller 13 by driving the transfer belt 10, and transferred to the paper transported from the paper supply unit 14 by the transfer roller 13.

  The sheet on which the toner image is transferred is conveyed to the fixing device 19. The fixing device 19 serves as a fixing unit that fixes the toner image on the paper by performing heat treatment and pressure treatment on the paper. Printed paper is placed on the paper discharge tray 20.

(About developing cartridge)
Next, the developing cartridge 7 will be described with reference to FIGS. FIG. 2 is a cross-sectional structure diagram of the developing cartridge 7 in the direction perpendicular to the axial direction of the developing roller 31 included in the developing cartridge 7. FIG. 3 is an external perspective view of the developing cartridge 7. FIG. 4 is a diagram showing the magnetic poles of the magnets 41 and 42 attached to the developing cartridge 7. More specifically, FIG. 4 (a) is a front view of the magnet, and FIG. 4 (b) is a sectional structural view taken along the line AA ′ of the magnet.

  The developing cartridge 7 is detachably attached to the image forming apparatus 1 and includes a container 30, a developing roller 31, a supply roller 32, and a stirring roller 33, as shown in FIG.

  The container 30 serves to store a developer containing a magnetic material, and has an opening O at the top. The stirring roller 33 is rotatably mounted in the container 30 and plays a role of stirring the developer and charging the toner in the developer. The supply roller 32 is rotatably mounted in the container 30 and serves to supply the developer stirred by the stirring roller 33 to the developing roller 31. The supply roller 32 and the agitation roller 33 each include a shaft 32 ′ and a shaft 33 ′ made of a magnetic material.

  The developing roller 31 is rotatably mounted in the container 30 and carries the developer supplied by the supply roller 32 on its peripheral surface. A part of the developing roller 31 is exposed from the opening O. The developing roller 31 faces the photosensitive drum 4 provided in the image forming apparatus 1 through the opening O, and forms a toner image on the peripheral surface of the photosensitive drum 4.

  Here, the developing roller 31 rotates clockwise as shown in FIG. 2 during printing. The toner remaining on the peripheral surface of the developing roller 31 after the toner image is formed on the photosensitive drum 4 is collected in the container 30 through the gap G formed between the container 30 and the developing roller 31. Therefore, the gap G has a gap (about 1 to 1.5 mm) enough to collect the developer.

  However, if such a gap G exists, the developer may leak from the gap G when the developing cartridge 7 is transported. More specifically, when the developing cartridge 7 is stood so that the axial direction of the developing roller 31 is vertical, the developer in the container 30 is concentrated downward due to gravity. When the developing cartridge 7 falls in this state, the developer concentrated on the lower side of the developing cartridge 7 leaks from the gap G.

  Therefore, in the developing cartridge 7 according to the present embodiment, as shown in FIGS. 2 and 3, the developer in the container 30 is not concentrated on one end during transportation. Magnets 41, 42, 43L, and 43R are removably attached and packed.

  Specifically, as shown in FIG. 4, the magnets 41 and 42 are magnets formed so that the south pole and the north pole are alternately arranged in the axial direction of the developing roller 31. As shown, it is arranged so as to be substantially parallel to the developing roller 31. The magnet 41 is disposed so as to face the developing roller 31 with the wall surface of the container 30 and the gap G interposed therebetween. The magnet 42 is disposed so as to face the supply roller 32 with the wall surface of the container 30 interposed therebetween. The magnets 41 and 42 are fixed by a tape T, for example.

  Further, the magnets 43L and 43R are respectively disposed at both ends of the shaft 32 ′ of the supply roller 32 as shown in FIG. At this time, as shown in FIG. 5, the magnet 43L and the magnet 43R are arranged so that the same magnetic pole (the S pole in FIG. 5) faces each other across the shaft 32 ′. FIG. 5 is a diagram illustrating the magnetic field φ generated on the shaft 32 ′ of the supply roller 32. The magnets 43L and 43R are fixed by a tape T, for example.

(effect)
In the developing cartridge 7 configured as described above, it is possible to effectively prevent the developer from leaking from the gap G even if the developing cartridge 7 falls down from the standing state. This will be described in detail below.

  In the developing cartridge 7 according to the present embodiment, as shown in FIG. 4, magnets 41 and 42 in which S poles and N poles are alternately formed in the longitudinal direction are used. Accordingly, the magnetic field is generated mainly in the longitudinal direction of the magnets 41 and 42 as shown in FIG. When such magnets 41 and 42 are attached to the container 30 such that the longitudinal direction thereof coincides with the axial direction of the developing roller 31, the developer containing the magnetic material in the container 30 is separated from the wall surface of the container 30. And the movement of the developing roller 31 in the axial direction is restricted. Therefore, even when the developing cartridge 7 is stood up, the concentration of the developer on one end of the container 30 due to gravity is reduced. As a result, even if the developer cartridge 7 falls from the standing state, the developer is effectively prevented from leaking from the gap G.

  In the developing cartridge 7 according to the present embodiment, the magnets 43L and 43R are disposed at both ends of the shaft 32 ′ of the supply roller 32. At this time, since the magnet 43L and the magnet 43R are arranged so that the south poles face each other, the north and south poles are alternately formed in the axial direction of the shaft 32 ′. More specifically, an S pole is formed at the axial center of the shaft 32 ', and N poles are formed at both ends of the shaft 32' in the axial direction. As a result, the developer containing the magnetic material is attracted to the central portion in the axial direction of the shaft 32 '. Therefore, even when the developing cartridge 7 is stood up, the concentration of the developer on one end of the container 30 due to gravity is reduced. As a result, even if the developer cartridge 7 falls from the standing state, the developer is effectively prevented from leaking from the gap G.

(Modification)
In the developing cartridge 7 according to this embodiment, the magnet 41 may have a structure in which the S pole and the N pole are arranged in a part of the longitudinal direction as shown in FIG. Good. More specifically, at the both ends and the central portion of the magnet 41 in the longitudinal direction, the S pole and the N pole are formed to be aligned in the longitudinal direction, and in the region sandwiched between both ends and the central portion, the longitudinal direction The S pole and the N pole may be formed so as to be aligned in a direction orthogonal to. A magnet formed so that the S pole and the N pole are arranged in a part of the longitudinal direction, and the S pole and the N pole are arranged in a direction orthogonal to the longitudinal direction in the other part of the longitudinal direction. By arranging 41 near the gap G, it is possible to restrict the developer present in the gap G from moving in the axial direction and the circumferential direction of the developing roller 31. As a result, it is possible to prevent the developer from concentrating on one end of the container 30 and to prevent the developer from leaking from the gap G.

  In the developing cartridge 7 according to this embodiment, the shaft 32 ′ of the supply roller 32 may be provided with a nonmagnetic material (shaded portion) in part as shown in FIG. 7. More specifically, the shaft 32 ′ may be formed such that a magnetic body and a non-magnetic body are alternately arranged in the axial direction. As a result, more magnetic poles appear, and it is possible to more effectively limit the movement of the developer in the axial direction. Examples of the nonmagnetic material include resin and aluminum.

  In the developing cartridge 7 according to this embodiment, the magnets 43L and 43R are attached to both ends of the shaft 32 ′ of the supply roller 32, but may be attached to both ends of the shaft 33 ′ of the stirring roller 33.

  The image forming apparatus 1 is a color printer, but may be a copier, a facsimile, or the like.

  Here, when the image forming apparatus 1 is a copying machine, not only the developing cartridge 7 is replaced as in the printer, but the image forming cartridge 57 including the developing cartridge 7 and the photosensitive drum 4 is replaced. Sometimes. Therefore, magnets 41, 42, 43L, and 43R may be attached to the image forming cartridge 57 as shown in FIG. In the image forming cartridge 57 shown in FIG. 8, since the photosensitive drum 4 and the developing roller 31 face each other, it is difficult to close the gap G with a sealing material or the like. Therefore, in such an image forming cartridge 57, it is particularly effective to prevent leakage of the developer by using the magnets 41, 42, 43L, and 43R.

1 is a diagram illustrating an overall configuration of an image forming apparatus including a developing cartridge according to the present invention. FIG. 4 is a cross-sectional structure diagram of the developing cartridge in a direction perpendicular to the axial direction of the developing roller. FIG. 2 is an external perspective view of a developing cartridge. Fig.4 (a) is a front view of a magnet, FIG.4 (b) is a cross-section figure in AA 'of a magnet. It is a figure explaining the magnetic field which generate | occur | produces on the axis | shaft of a supply roller. It is the figure which showed the modification of the magnet. It is the figure which showed the modification of the axis | shaft of a supply roller. 2 is a cross-sectional structure diagram of an image forming cartridge in a direction perpendicular to an axial direction of a developing roller. FIG. FIG. 2 is a cross-sectional structure diagram of a general developing cartridge in a direction perpendicular to an axial direction of a developing roller. FIG. 3 is a cross-sectional structure diagram of the developing cartridge in a direction perpendicular to an axial direction of a developing roller in a state where a magnet is attached. FIG. 11A is a front view of a magnet attached to the container of the developing cartridge, and FIG. 11B is a side view of the magnet.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 4 Photosensitive drum 7 Developing cartridge 30 Container 31 Developing roller 32 Supply roller 32 ', 33' Shaft 33 Stirring roller 41, 42, 43L, 43R Magnet 57 Image forming cartridge G Gap O Opening

Claims (9)

In a developing cartridge that is detachably attached to an image forming apparatus,
A container for storing a developer containing a magnetic material;
A developing roller attached in the container so that a part is exposed through an opening formed in the container;
A magnet removably attached to the container so that two types of magnetic poles are alternately formed in the axial direction of the developing roller;
Providing
A developing cartridge characterized by the above. The magnet is a magnet formed so that two kinds of magnetic poles are alternately arranged in the axial direction of the developing roller, and is disposed so as to be substantially parallel to the developing roller;
The developing cartridge according to claim 1. The magnet is disposed to face the developing roller across the wall surface of the container;
The developing cartridge according to claim 2. A supply roller mounted in the container and supplying the developer to the developing roller;
In addition,
The magnet is disposed so as to face the supply roller across the wall surface of the container;
The developing cartridge according to claim 2, wherein the developing cartridge is a cartridge. A supply roller having a shaft made of a magnetic material and attached to the container and supplying the developer to the development roller;
In addition,
The magnets are disposed at both ends of the supply roller;
The developing cartridge according to claim 1. The magnets are arranged so that the same magnetic poles face each other across the supply roller;
The developing cartridge according to claim 5. A stirring roller having a shaft made of a magnetic material and mounted in the container and stirring the developer;
In addition,
The magnets are disposed at both ends of the stirring roller;
The developing cartridge according to claim 1. The magnets are arranged so that the same magnetic poles face each other across the stirring roller;
The developing cartridge according to claim 7. In an image forming cartridge that is detachably attached to an image forming apparatus,
A container for storing a developer containing a magnetic material;
A developing roller attached in the container so that a part is exposed through an opening formed in the container;
A photoconductor facing the developing roller through the opening;
A magnet removably attached to the container so that two types of magnetic poles are alternately formed in the axial direction of the developing roller;
Providing
An image forming cartridge characterized by

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