Patent ID: 12204274

DETAILED DESCRIPTION

An embodiment of the present disclosure will next be described in detail while referring to the accompanying drawings.

As illustrated inFIG.1, a developing cartridge1includes a casing11, a developing roller12, a supply roller13(seeFIG.2), a handgrip14, a layer thickness regulation blade20, a developing electrode30, a supply electrode100, and a bearing60. The supply electrode100is a member electrically connected to the supply roller13and the layer thickness regulation blade20. The supply electrode100includes an electrode member40and a spring50.

The casing11accommodates therein toner. The casing11is made of non-conductive resin. The casing11includes a side wall15. The side wall15is positioned at one end of the developing roller12.

The developing roller12is a roller configured to supply toner to an electrostatic latent image formed on a photosensitive body (not illustrated). The developing roller12is rotatable about a first axis X1extending in an axial direction. The developing roller12includes a shaft12A (seeFIG.2) extending in the axial direction. The developing roller12is positioned at one end11A of the casing11.

As illustrated inFIG.2, the supply roller13is a roller configured to supply toner to the developing roller12. The supply roller13is rotatable about a second axis X2extending in the axial direction. The supply roller13includes a shaft13A extending in the axial direction. The supply roller13is in contact with the developing roller12.

Turning back toFIG.1, the handgrip14is a portion configured to be gripped by a user. The handgrip14is positioned at the other end11B of the casing11.

The layer thickness regulation blade20is a member configured to regulate a thickness of a toner layer formed on the developing roller12. The layer thickness regulation blade20includes a blade21and a support member22supporting the blade21.

The blade21is a rectangular metal plate extending in the axial direction. The blade21is made of metal such as stainless steel. The blade21has a thickness smaller than that of the support member. One end of the blade21in the short direction thereof is fixed to the support member22by welding, etc. The other end of the blade21in the short direction thereof is in contact with a circumferential surface of the developing roller12.

Incidentally, a rubber member may be provided at the other end in the short direction of the blade21. In this case, the rubber member of the blade21may be in contact with the developing roller12.

The support member22is made of metal such as an electrogalvanized steel plate. The support member22includes a first wall22A and a second wall22B. The first wall22A supports a surface of the blade21which is opposite to a surface of the blade21facing the developing roller12. The second wall22B is positioned at one end portion of the first wall22A which is farther from the developing roller12than the other end portion of the first wall22A is from the developing roller12. The second wall22B extends from the first wall22A in a direction away from the blade21.

The first wall22A includes two protruding portions22C. Each protruding portion22C protrudes further in a direction away from the developing roller12than the second wall22B. The second wall22B is positioned between the two protruding portions22C in the axial direction. Each protruding portion22C has a through-hole22D through which a first screw S1(only one screw is depicted) is inserted. Each protruding portion22C is fastened to the casing11by the corresponding first screw S1.

As illustrated inFIG.2, the casing11includes a fixing wall16to which the protruding portion22C is fixed. The side wall15has an opening15A extending therethrough in the leftward/rightward direction. The opening15A is overlapped with the fixing wall16and the protruding portion22C as viewed in the axial direction. A part of the opening15A is positioned closer to the one end11A of the casing11than the protruding portion22C is to the one end11A. With this configuration, by inserting a contact portion53D (described later) of the spring50through the opening15A, the contact portion53D can be inserted toward the blade21further than the side wall15.

The casing11has a boss17. The boss17has a tip end to which a second screw S2is fixed for co-fastening the electrode member40, the bearing60, and the developing electrode30. The casing11includes a protruding portion18protruding from the side wall15toward the electrode member40. The protruding portion18has a cam surface18A. The cam surface18A is a surface for moving the electrode member40in a direction perpendicular to the second axis X2. The cam surface18A is inclined so as to approach the side wall15with increasing distance from the second axis X2.

The developing electrode30is a member electrically connected to the shaft12A of the developing roller12. The developing electrode30is made of electrically conductive resin. The developing electrode30includes a first contact portion31and a cover portion32, and has an attachment hole33.

The first contact portion31is a surface configured to contact with a first main body side electrode in the axial direction in a state where the developing cartridge1is attached to a main body casing of an image forming apparatus (not illustrated). The first main body side electrode is provided at the main body casing. The first contact portion31is perpendicular to the axial direction. The first contact portion31is positioned at a position different from the position of the shaft12A of the developing roller12.

The cover portion32is formed in a generally hollow cylindrical shape so as to cover a circumferential surface of the shaft12A of the developing roller12. The inner circumferential surface of the cover portion32is in contact with the shaft12A of the developing roller12.

The attachment hole33is a hole through which the second screw S2is inserted. The attachment hole33faces the boss17of the casing11in the axial direction. The developing electrode30is fixed to the boss17by the second screw S2.

The bearing60is made of non-conductive resin. The bearing60includes a base portion60A, a first support portion61, a second support portion62, a first protruding portion65, and a second protruding portion66, and has a through-hole63. The base portion60A is formed in a flat plate shape perpendicular to the axial direction. The bearing60is positioned between the developing electrode30and the electrode member40in the axial direction.

The first support portion61is formed in a hollow cylindrical shape protruding from the base portion60A toward the casing11. The inner circumferential surface of the first support portion61supports the shaft12A of the developing roller12.

The second support portion62includes: a hollow cylindrical portion protruding from the base portion60A in a direction away from the casing11; and a bottom portion closing the opening of the tip end of the hollow cylindrical portion. The inner circumferential surface of the second support portion62supports the shaft13A of the supply roller13.

The through-hole63is a circular through-hole through which the boss17of the casing11is inserted. The through-hole63is positioned at a position facing the boss17in the axial direction.

The first protruding portion65and the second protruding portion66protrude from the base portion60A in a direction away from the casing11. The first protruding portion65is positioned adjacent to a first side41A of a second contact portion41(described later) of the electrode member40. The second protruding portion66is positioned adjacent to a second side41B of the second contact portion41, the second side41B being perpendicular to the first side41A.

The electrode member40is a member electrically connected to the shaft13A that is a rotation shaft of the supply roller13. The electrode member40is made of electrically conductive resin. The electrode member40includes a base40A, a first portion42, and a second portion44. The electrode member40is movable in a direction perpendicular to the shaft13A of the supply roller13.

The base40A is formed in a flat plate shape perpendicular to the axial direction. The base40A has a hole43. The base40A connects the first portion42and the second portion44. The base40A is positioned between the bearing60and the casing11in the axial direction.

The hole43is a hole for fixing the electrode member40to the casing11. The boss17of the casing11is inserted through the hole43. The diameter of the hole43is greater than the outer diameter of the boss17. A rib45protruding from the base40A in a direction away from the casing11is formed at the periphery of the hole43. The rib45is formed in a generally arcuate shape as viewed in the axial direction.

The first portion42is formed in a hollow cylindrical shape protruding from the base40A toward the casing11. The inner circumferential surface of the first portion42is in contact with the shaft13A of the supply roller13.

The second portion44is positioned at a position different from the position of the first portion42. The second portion44protrudes from the base40A in a direction away from the casing11. The end surface of the second portion44serves as the second contact portion41. The second contact portion41is a surface configured to contact with a second main body side electrode in the axial direction in a state where the developing cartridge1is attached to the main body casing of the image forming apparatus (not illustrated). The second main body side electrode is provided at the main body casing. That is, the second portion44is in contact with the second main body side electrode that is an external electrode.

The second contact portion41has a rectangular shape as viewed in the axial direction. The second contact portion41is perpendicular to the axial direction. The second contact portion41is positioned at a position different from the position of the shaft13A of the supply roller13. Specifically, the second contact portion41is positioned at a position opposite to the first portion42with respect to the hole43.

The electrode member40is connected to the blade21through the spring50. That is, the electrode member40is electrically connected to the blade21through a member other than the support member22. The electrode member40is movable relative to the spring50in a direction perpendicular to the shaft13A of the supply roller13in a state where the electrode member40is in contact with the spring50.

The spring50is a member for electrically connecting the base40A of the electrode member40and the blade21. The spring50is made of metal. The spring50includes a coil portion51, an arm portion52and a nipping portion53. As illustrated inFIG.3, the coil portion51extends in the axial direction of the supply roller13. The coil portion51is positioned between the base40A and the casing11. That is, the spring50is positioned between the base40A and the casing11. The coil portion51is in contact with the base40A and the casing11. The coil portion51is compressed from its natural length in a state where the electrode member40is assembled to the casing11.

In the state where the electrode member40is assembled to the casing11, the boss17is inserted in the coil portion51. Hence, the coil portion51is supported by the outer circumferential surface of the boss17.

Turning back toFIG.2, the arm portion52is formed in a line shape. The arm portion52extends toward the blade21from one end portion of the coil portion51which is closer to the casing11than the other end portion of the coil portion51is to the casing11. Specifically, the arm portion52extends outward in the radial direction of the coil portion51from the one end portion of the coil portion51. More specifically, the arm portion52extends from the coil portion51toward the one end11A of the casing11. The arm portion52includes the nipping portion53. The nipping portion53nips and supports the blade21and the fixing wall16which is a part of the casing11. The nipping portion53is provided at a distal end of the arm portion52.

As illustrated inFIG.3, the nipping portion53nips the fixing wall16, the support member22, and the blade21together to support them. The nipping portion53has a U-shape as viewed in a direction which is perpendicular to both the axial direction and a direction perpendicular to a surface of the blade21. Here, this surface of the blade21is the opposite surface to the surface of the blade21facing the support member22.

The nipping portion53mainly includes a first part53A, a second part53B, a third part53C, and the contact portion53D. The first part53A extends in the axial direction. The first part53A is in contact with the fixing wall16.

The second part53B extend toward the one end11A (seeFIG.2) of the casing11from one end portion of the first part53A which is farther from the casing11than the other end portion of the first part53A is from the casing11. The second part53B is positioned spaced away from the fixing wall16, the support member22and the blade21in the axial direction.

The third part53C extends toward the blade21from one end portion of the second part53B which is farther from the first part53A than the other end portion of the second part53B is from the first part53A. The third part53C is inclined with respect to the surface of the blade21. Specifically, the third part53C is inclined so as to approach the first part53A with decreasing distance in the axial direction between the third part53C and the blade21.

The contact portion53D is a portion which is in contact with the surface of the blade21. The contact portion53D is provided at one end portion of the third part53C which is closer to the blade21than the other end portion of the third part53C is to the blade21.

As illustrated inFIG.4, the contact portion53D is formed in a U-shape as viewed in a direction perpendicular to the surface of the blade21. Specifically, the contact portion53D has a U-shape which opens toward the side wall15of the casing11. The contact portion53D extends toward the developing roller12from the third part53C as viewed in a direction perpendicular to the surface of the blade21.

A fourth part54E is provided at one end portion of the contact portion53D which is farther from the third part53C than the other end portion of the contact portion53D is from the third part53C. The fourth part53E is inclined so as to approach the third part53C as the fourth part53E advances toward the side wall15from the contact portion53D.

As illustrated inFIGS.5A and5B, the second portion44is formed in a box shape which opens toward the casing11. The second portion44has a bottom surface44A. The second portion44includes a rib46protruding toward the casing11from the bottom surface44A.

The rib46extends along a diagonal line of the rectangular second contact portion41. The rib46intersects the protruding portion18(seeFIG.2) of the casing11as viewed in the axial direction. The rib46has an end surface functioning as a cam surface46A in conformance with the cam surface18A of the protruding portion18of the casing11. That is, the cam surface46A is inclined so as to approach the casing11with increasing distance from the second axis X2.

Incidentally, the electrode member40is urged toward the bearing60by the spring50. Thus, the surface of the electrode member40which faces the casing11is spaced away from the side wall15.

Next, functions and effects of each member in accordance with attachment of the developing cartridge1to the main body casing will be described.

As a result of attachment of the developing cartridge1illustrated inFIG.1to the main body casing, the first main body side electrode is brought into contact with the first contact portion31of the developing electrode30in the axial direction, and the second main body side electrode is brought into contact with the second contact portion41of the electrode member40in the axial direction. Here, each of the first main body side electrode and the second main body side electrode has a spring. Hence, the second main body side electrode urges the electrode member40toward the casing11.

As a result of the electrode member40being urged toward the developing cartridge1, the cam surface46A of the rib46is pressed against the cam surface18A of the casing11as illustrated inFIG.5B. Hence, as illustrated inFIG.3, the electrode member40is pressed in a direction away from the second axis X2by the cam surface18A of the casing11. Thus, the first portion42of the electrode member40can be caused to satisfactorily contact with the shaft13A of the supply roller13.

When performing printing control, a control device provided in the main body casing supplies electric power to the developing roller12, the supply roller13, and the blade21. Specifically, the control device supplies electric power to the shaft12A of the developing roller12through the developing electrode30. Moreover, the control device supplies electric power to the shaft13A of the supply roller13through the electrode member40. Furthermore, the control device supplies electric power to the blade21through both the electrode member40and the spring50.

According to the present embodiment, the following effects can be obtained in addition to the above-described effects.

In the present embodiment as constructed above, electric power can be satisfactorily supplied to the layer thickness regulation blade20.

In the present embodiment, since the supply electrode100is electrically connected to the blade21without intervention of the support member22, electric power can be satisfactorily supplied to the blade21in comparison with a connection configuration with intervention of the support member22whose electrical conductivity has been lowered due to surface treatment.

In the present embodiment, since the spring50is interposed between the base40A of the electrode member40and the casing11, a good contact state between the spring50and the base40A can be maintained.

In the present embodiment, the position of the spring50can be favorably fixed relative to the casing11since the coil portion51of the spring50is supported by the outer circumferential surface of the boss17.

In the present embodiment, because the fixing wall16(a part of the casing11) and the blade21(the layer thickness regulation blade20) are nipped by the nipping portion53of the spring50, a good contact state between the spring50and the blade21(the layer thickness regulation blade20) can be maintained.

Further, in the present embodiment, voltage can be applied to the layer thickness regulation blade20through the electrode member40in spite of the fact that a structure in which the electrode member40is movable is employed for ensuring electrical connection between the supply roller13and the electrode member40.

Moreover, in the present embodiment, the coil portion51can be caused to satisfactorily contact with the base40A because the coil portion51is positioned between the base40A and the casing11.

While the description has been made in detail with reference to the specific embodiment, it would be apparent to those skilled in the art that many modifications and variations may be made thereto and various embodiments are conceivable. In the following description, like parts and components are designated by the same reference numerals as those shown in the above-described embodiment to avoid duplicating description.

In the above-described embodiment, the electrode member40is connected to the blade21through the spring50. However, the electrical connection configuration between the electrode member40and the blade21is not limit to this structure. For example, as illustrated inFIG.6, the electrode member40may be connected to the blade21through a connection member70made of electrically conductive resin or metal.

Specifically, according to this embodiment, a supply electrode200includes the electrode member40of the above-described embodiment and the connection member70. The connection member70includes a plate portion71and an extension portion72. The plate portion71faces the protruding portion22C of the support member22and the blade21. The plate portion71has a hole71A through which the first screw S1is inserted. As illustrated inFIG.7, the plate portion71is fixed to the casing11together with the protruding portion22C of the support member22by the first screw S1. The plate portion71is in contact with the blade21.

The extension portion72extends from the plate portion71toward the rib45of the electrode member40. Specifically, the extension portion72extends in a direction perpendicular to the plate portion71. The tip end portion of the extension portion72is in contact with the rib45. Also in this embodiment, since the supply electrode200is connected to the blade21without intervention of the support member22, electric power can be satisfactorily supplied to the blade21in comparison with a connection configuration with intervention of the support member22whose electrical conductivity has been lowered due to surface treatment. Furthermore, in this embodiment, since the connection member70and the support member22are co-fastened to the casing11, the connection member70can be caused to satisfactorily contact with the blade21(the layer thickness regulation blade20) by the fastening force of the co-fastening.

In the above-described embodiments, the connection member (50or70) is formed separately from the electrode member40. However, the connection member need not necessarily be formed separately from the electrode member40and the connection member may be formed integrally with the electrode member. For example, the connection member70illustrated inFIG.7may be formed integrally with the electrode member40.

Incidentally, the materials of the developing electrode30, electrode member40and the spring50can be changed as appropriate. For example, the developing electrode30and the electrode member40may be made of any other electrically conductive material such as metal. Moreover, the spring50may be made of any other electrically conductive material such as electrically conductive resin.

In the above-described embodiment, the spring50including the coil portion51has been described as an example of the spring. However, the spring is not limited to this structure. For example, a leaf spring may be used as the spring.

Further, implementation can be performed with any combination of the components employed in the above-described embodiments and modifications.