This application is a reissue of U.S. Pat. No. 10,042,282, which was filed as U.S. patent application Ser. No. 15/715,979 and filed on Sep. 26, 2017, and which claims priority from Japanese Patent Application No. 2016-256106 filed Dec. 28, 2016. The entire content of the Japanese priority application is incorporated herein by reference.
The present disclosure relates to a developing cartridge including a developing roller.
Conventionally, a developing cartridge includes a detection protrusion for moving an actuator positioned at a main body casing of an image forming apparatus. The detection protrusion has a gear. The detection protrusion is rotatable around a shaft. The actuator is moved by the detection protrusion pushing the actuator during rotation of the gear. Further, the gear has a toothless portion. In a case where the toothless portion faces a drive gear that transmits the drive force to the gear, meshing between the gear and the drive gear is released. As a result, the rotation of the gear stops. As the rotation of the gear stops, the rotation of the detection protrusion also stops.
Meanwhile, in the above-described developing cartridge, it has been desired to release meshing between a gear other than the gear and the drive gear.
In view of the foregoing, it is an object of the disclosure to provide a developing cartridge capable of releasing meshing between a gear other than the gear and the drive gear.
In order to attain the above and other objects, according to one aspect, the disclosure provides a developing cartridge including: a casing; a developing roller; a developing electrode; a gear; a rack gear; and a cam. The casing is configured to accommodate toner therein. The developing roller is rotatable about a first axis extending in an axial direction. The developing roller is positioned at one end of the casing. The developing electrode is electrically connected to the developing roller. The gear is rotatable about a second axis parallel with the first axis. The rack gear meshes with the gear. The rack gear is movable in a direction from the one end of the casing toward another end of the casing opposite to the one end of the casing. The rack gear includes a protrusion. The cam is movable from a first position to a second position. The second position is farther away from the casing than the first position is from the casing in the axial direction. The cam has: a first cam surface; and a second cam surface. The first cam surface contacts the protrusion in a case where the cam is at the first position. The first cam surface causes the cam to move from the first position to the second position in a case where the rack gear moves in the direction from the one end of the casing toward the another end of the casing in a state where the first cam surface is in contact with the protrusion. The second cam surface moves the developing electrode in a direction away from the cam while contacting the developing electrode in a case where the cam moves from the first position to the second position. The direction away from the cam is a direction different from a moving direction of the rack gear and a moving direction of the cam.
According to another aspect, the disclosure provides a developing cartridge including: a casing; a developing roller; a gear; a developing electrode; a rack gear; a cover; and a cam. The casing is configured to accommodate toner therein. The developing roller is rotatable about a first axis extending in an axial direction. The developing roller is positioned at one end of the casing. The gear is rotatable about a second axis extending in the axial direction. The developing electrode is electrically connected to the developing roller. The rack gear is movable from the one end of the casing toward another end of the casing opposite to the one end of the casing. The rack gear is movable in a direction from the one end of the casing toward the another end of the casing in accordance with rotation of the gear by meshing with the gear. The rack gear includes a protrusion. The cover covers at least a portion of the rack gear. The cover has an opening through which the developing electrode is exposed to an outside. The cam is movable from a first position to the second position. The second position is farther away from the casing than the first position is from the casing in the axial direction. The cam has: a first cam surface; and a second cam surface. The first cam surface has a first edge and a second edge. The second edge is positioned farther away from the casing than the first edge is from the casing in the axial direction. The first cam surface is inclined so that the first edge is positioned downstream relative to the second edge in a moving direction of the protrusion. The first cam surface causes the cam to move from the first position to the second position by engaging with the protrusion. The first cam surface is positioned outside of a movement locus of the protrusion in a case where the cam is at the second position. The second cam surface is movable together with the first cam surface. The second cam surface is positioned farther away from the casing than the first cam surface is from the casing in the axial direction. The second cam surface is movable while contacting the developing electrode. The second cam surface has a fifth edge and a sixth edge. The sixth edge is positioned farther away from the casing than the fifth edge is from the casing in the axial direction. The second cam surface is inclined so as to protrude toward the opening in a direction from the sixth edge toward the fifth edge.
According to still another aspect, the disclosure provides a developing cartridge including: a casing; a developing roller; a gear; a rack gear; a cam; a spring; a cover; and a developing electrode. The casing is configured to accommodate toner therein. The developing roller is rotatable about a first axis extending in an axial direction. The developing roller is positioned at one end of the casing. The gear is rotatable about a second axis parallel with the first axis. The rack gear meshes with the gear. The rack gear is movable in a direction from the one end of the casing toward another end of the casing opposite to the one end of the casing. The cam is movable from a first position to a second position. The second position is farther away from the casing than the first position is from the casing in the axial direction. The cam includes a protrusion. The spring urges the cam from the first position toward the second position. The cover has an opening. The developing electrode is electrically connected to the developing roller. The developing electrode is movable together with the cam. The developing electrode has a second cam surface. The second cam surface has a fifth edge and a sixth edge. The sixth edge is positioned farther away from the casing than the fifth edge is from the casing in the axial direction. The second cam surface is inclined so as to protrude toward the opening in a direction from the sixth edge toward the fifth edge. The rack gear has: a first holding surface contacting the protrusion to hold the cam at the first position; and a second holding surface contacting the protrusion to hold the cam at the second position.
The particular features and advantages of the embodiment(s) as well as other objects will become apparent from the following description taken in connection with the accompanying drawings, in which:
A developing cartridge according to a first embodiment will be described with reference to
As illustrated in
The developing roller 12 is a roller that supplies toner to an electrostatic latent image formed on a photosensitive member (not illustrated). The developing roller 12 is rotatable about a first axis X1 extending in the axial direction. The developing roller 12 has a shaft 12A extending in the axial direction. The developing roller 12 is positioned at one end E10 of the casing 11in, where the end E10 is defined relative to a direction that extends from the shaft 12A toward a shaft 14A of the agitator 14 described later.
The supply roller 15 is a roller that supplies toner to the developing roller 12. The agitator 14 is a member that agitates the toner inside the casing 11.
The coupling 13 is a member that receives a driving force from outside. Specifically, in a case where an input member (not illustrated) capable of advancing and retracting is provided at a main body casing (not illustrated) of an image forming apparatus (not illustrated) and the input member advances and enters the coupling 13 to engage with the coupling 13 in a rotational direction, the driving force is inputted into the coupling 13 from the input member. The driving force inputted into the coupling 13 is transmitted to the developing roller 12 via a gear mechanism (not illustrated) and is also transmitted to the supply roller 15 and the agitator 14.
The coupling 13 is positioned at one end of the casing 11 in the axial direction. In other words, the coupling 13 is positioned opposite to a developing electrode 20 (see
As illustrated in
As the driving force inputted into the coupling 13 is transmitted to the developing electrode 20 through the gear mechanism and the agitator 14 (see
As illustrated in
The developing electrode 20 and the bearing 40 are made of an electrically-conductive material. Specifically, the developing electrode 20 and the bearing 40 are made of an electrically-conductive resin. The electrically-conductive resin is, for example, a polyacetal resin containing carbon powder.
The agitator gear 31 is mounted to the other end portion of the shaft 14A of the agitator 14. The agitator gear 31 is rotatable about a second axis X2 parallel with the first axis X1. The agitator gear 31 rotates together with the shaft 14A of the agitator 14. That is, the agitator gear 31 rotates together with the developing roller 12 by the driving force inputted into the coupling 13.
The bearing 40 is a member for rotatably supporting the shaft 12A of the developing roller 12 and a shaft 15A of the supply roller 15. The bearing 40 includes a plate-like portion 41, a first bearing portion 42, a second bearing portion 43, and two first guide portions 44.
The plate-like portion 41 is a plate-like portion that extends in the direction from the shaft 12A toward the shaft 14A. Specifically, the plate-like portion 41 extends from the shaft 12A of the developing roller 12 toward the agitator gear 31. The plate-like portion 41 is positioned, in the axial direction, between the side wall 11A at the other end of the casing 11 in the axial direction and the rack gear 50.
Specifically, the plate-like portion 41 is positioned in a recessed portion 11B positioned at an outer surface of the side wall 11A. Hence, an outer surface of the plate-like portion 41 and the outer surface of the side wall 11A are substantially flush with each other (see
The first bearing portion 42 is a hollow cylindrical portion that rotatably supports the shaft 12A of the developing roller 12. The first bearing portion 42 protrudes from the plate-like portion 41 in a direction away from the casing 11 in the axial direction. Specifically, the first bearing portion 42 protrudes farther than the second bearing portion 43 in the direction away from the casing 11 in the axial direction.
The second bearing portion 43 is a hollow cylindrical portion that rotatably supports the shaft 15A of the supply roller 15. The second bearing portion 43 protrudes from the plate-like portion 41 in the direction away from the casing 11 in the axial direction. The second bearing portion 43 is positioned at a position closer to the agitator gear 31 than the first bearing portion 42 is to the agitator gear 31.
Each of the first guide portions 44 is a portion that movably supports the rack gear 50 in a direction from the one end E10 of the casing 11 (described later) toward the other end E20 of the casing 11. The two first guide portions 44 are provided so as to interpose the rack gear 50 therebetween. Each of the first guide portions 44 supports the rack gear 50. Each of the first guide portions 44 protrudes from the plate-like portion 41 in the direction away from the casing 11 in the axial direction. Each of the first guide portions 44 has a plate shape orthogonal to the plate-like portion 41. Each of the first guide portions 44 has a first length in the direction from the one end E10 of the casing 11 toward the other end E20 of the casing 11, and a second length in the axial direction. The first length is greater than the second length. Each of the first guide portions 44 is positioned at a position closer to the agitator gear 31 than the second bearing portion 43 is to the agitator gear 31.
The casing 11 includes a second guide portion 11C, a third guide portion 11D, and a fourth guide portion 11E. The second guide portion 11C, the third guide portion 11D, and the fourth guide portion 11E each movably support the rack gear 50 in the direction from the one end E10 of the casing 11 toward the other end E20 of the casing 11. The second guide portion 11C is positioned opposite to the third guide portion 11D and the fourth guide portion 11E with respect to the rack gear 50. The second guide portion 11C spans a range from the third guide portion 11D to the fourth guide portion 11E and extends in the direction from the one end E10 of the casing 11 toward the other end E20 of the casing 11.
The third guide portion 11D and the fourth guide portion 11E face a surface of the rack gear 50 facing the agitator gear 31. The third guide portion 11D is positioned at a position closer to the developing roller 12 than the agitator gear 31 is to the developing roller 12. The fourth guide portion 11E is positioned opposite to the third guide portion 11D with respect to the agitator gear 31 in the direction from the one end E10 of the casing 11 toward the other end E20 of the casing 11.
The rack gear 50 is movable in the direction from the one end E10 of the casing 11 toward the other end E20 of the casing 11 opposite to the one end E10. The rack gear 50 includes a main body portion 51, a rack gear portion 52, and a first protrusion 53 and a second protrusion 54 as an example of a protrusion.
The main body portion 51 has a rectangular plate shape that is elongated in the direction from the one end E10 of the casing 11 toward the other end E20 of the casing 11. The rack gear portion 52 has a plurality of gear teeth meshing with the agitator gear 31. The main body portion 51 extends in a moving direction of the rack gear 50. The rack gear portion 52 and the respective protrusions 53 and 54 protrude from a surface of the main body portion 51 facing the agitator gear 31. The rack gear 50 is configured to move in the direction from the one end E10 of the casing 11 toward the other end E20 of the casing 11 only while the rack gear portion 52 is meshed with the agitator gear 31. The rack gear 50 is configured to stop moving in a case where meshing between the rack gear portion 52 and the agitator gear 31 is released. That is, the rack gear 50 is movable in the direction from the one end E10 of the casing 11 toward the other end E20 of the casing 11 as the agitator gear 31 rotates.
The rack gear portion 52 is positioned at a downstream portion of the main body portion 51 in the moving direction of the rack gear 50 in an end portion of the main body portion 51 closer to the casing 11 in the axial direction. Specifically, the rack gear portion 52 is positioned at the main body portion 51 at a region from an end portion of the main body portion 51 closer to the agitator gear 31 in the moving direction of the rack gear 50 to a center portion of the main body portion 51 in the moving direction of the rack gear 50 (see
The first protrusion 53 and the second protrusion 54 are positioned at positions different from the rack gear portion 52 in the moving direction of the rack gear 50. The first protrusion 53 and the second protrusion 54 are positioned at positions different from the rack gear portion 52 in the axial direction. Specifically, the first protruion 53 and the second protrusion 54 are positioned at the main body portion 51 at positions farther from the casing 11 than the rack gear portion 52 is from the casing 11 in the axial direction. Further, the first protrusion 53 and the second protrusion 54 are positioned at positions closer to the developing roller 12 than the rack gear portion 52 is to the developing roller 12 in the moving direction of the rack gear 50. More specifically, the first protrusion 53 is positioned in the vicinity of the center portion of the main body portion 51 in the moving direction of the rack gear 50. The second protrusion 54 is positioned at an end portion of the main body portion 51 closer to the developing roller 12 in the moving direction. The first protrusion 53 and the second protrusion 54 are capable of contacting a first cam surface 73A and a third cam surface 74A of a cam 70 (see
The gear cover 60 covers the agitator gear 31 and the rack gear 50. As illustrated in
The gear cover 60 includes a first cover portion 61, a second cover portion 62, and a third cover portion 63. The first cover portion 61 covers the rack gear 50 and the agitator gear 31. The second cover portion 62 covers the cam 70 and the developing electrode 20. The third cover portion 63 covers the compression coil spring SP. The first cover portion 61 is elongated in the direction from the one end E10 of the casing 11 toward the other end E20 of the casing 11 so that the rack gear 50 can be covered by the first cover portion 61 before, while, and after the rack gear 50 moves.
The second cover portion 62 protrudes away from the casing 11 in the axial direction. The second cover portion 62 protrudes away from a substantially center portion of the first cover portion 61in, where the substantially center portion of the first cover portion 61 is defined relative to the direction from the one end E10 of the casing 11 toward the other end E20 of the casing 11. The second cover portion 62 has an internal space that is in communication with an internal space of the first cover portion 61. Further, the second cover portion 62 has an opening 62A through which the developing electrode 20 is exposed to outside.
The third cover portion 63 has a through-hole 63A penetrating the thickness of the third cover portion 63 in the axial direction. The compression coil spring SP is positioned inside the through-hole 63A. The third cover portion 63 is positioned at a position substantially the same as the second cover portion 62 in the direction from the one end E10 of the casing 11 toward the other end E20 of the casing 11. The third cover portion 63 protrudes from the first cover portion 61 in a direction away from the rack gear 50. The through-hole 63A is open toward the developing electrode 20.
Incidentally, in the present embodiment, a hollow portion of the third cover portion 63 is positioned between an outer peripheral surface of the third cover portion 63 and the through-hole 63A. However, the hollow portion may not be positioned between the outer peripheral surface of the third cover portion 63 and the through-hole 63A.
The cam 70 is positioned in the second cover portion 62 of the gear cover 60 so as to be movable in the axial direction. The cam 70 is movable between a first position illustrated in
The base portion 71 is a plate-like portion orthogonal to a direction in that the rack gear 50 and the cam 70 face each other. The base portion 71 has a first length in the axial direction, and a second length in the direction from the one end E10 of the casing 11 toward the other end E20 of the casing 11. The first length is greater than the second length. The rib 72 protrudes toward the rack gear 50 from an end portion of the base portion 71 closer to the casing 11.
The first cam portion 73 and the third cam portion 74 are positioned between the rib 72 and the protruding portion 75. The first cam portion 73 and the third cam portion 74 protrude from the base portion 71 toward the rack gear 50.
The first cam portion 73 is positioned at a position different from the third cam portion 74 in the moving direction of the rack gear 50. Specifically, the first cam portion 73 is positioned farther away from the agitator gear 31 in the moving direction of the rack gear 50 than the third cam portion 74 is from the agitator gear 31. The first cam portion 73 diagonally extends from the protruding portion 75 toward the rib 72. That is, the first cam portion 73 diagonally extends downstream in the moving direction of the rack gear 50 from the protruding portion 75. The first cam portion 73 has one end connected to the protruding portion 75, and the other end separated from the rib 72. An interval between the other end of the first cam portion 73 and the rib 72 is greater than a diameter of each of the protrusions 53 and 54 of the rack gear 50.
The first cam portion 73 has a first cam surface 73A that is inclined relative to the moving direction of the rack gear 50. The first cam surface 73A is a surface for moving the cam 70 in the direction away from the casing 11 in the axial direction. The first cam surface 73A is configured to contact the protrusions 53 and 54 of the rack gear 50 in a case where the cam 70 is at the first position. The first cam surface 73A is configured to move the cam 70 from the first position to the second position. Specifically, in a case where the rack gear 50 moves in the direction from the one end E10 of the casing 11 toward the other end E20 of the casing 11 in a state where the first cam surface 73A is in contact with the first protrusion 53 or the second protrusion 54, the first cam surface 73A causes the cam 70 to move from the first position toward the second position. In other words, the first cam surface 73A causes to move the cam 70 from the first position to the second position by engaging with the protrusions 53 and 54. In a case where the cam 70 is at the second position, the first cam surface 73A is positioned outside of a movement locus of the protrusions 53 and 54.
The first cam surface 73A is inclined so that a downstream edge of the first cam surface 73A in the moving direction of the rack gear 50 is positioned closer to the casing 11 than an upstream edge of the first cam surface 73A in the moving direction of the rack gear 50 is to the casing 11 in the axial direction. Specifically, the first cam surface 73A has a first edge E1, and a second edge E2. The second edge E2 is positioned farther away from the casing 11 than the first edge E1 is from the casing 11 in the axial direction. The first cam surface 73A is inclined so that the first edge E1 is positioned downstream relative to the second edge E2 in the moving direction of the rack gear 50.
The third cam portion 74 diagonally extends from a substantially center portion of the rib 72 in the direction from the one end E10 of the casing 11 toward the other end E20 of the casing 11 toward the protruding portion 75. That is, the third cam portion 74 diagonally extends downstream in the moving direction of the rack gear 50 from the substantially center portion of the rib 72. The third cam portion 74 has one end connected to the rib 72, and the other end separated from the protruding portion 75. An interval between the other end of the third cam portion 74 and the protruding portion 75 is greater than the diameter of each of the protrusions 53 and 54 of the rack gear 50.
The third cam portion 74 has a third cam surface 74A that is inclined relative to the moving direction of the rack gear 50. The third cam surface 74A is a surface for moving the cam 70 in a direction toward the casing 11 in the axial direction. The third cam surface 74A is configured to contact the protrusions 53 and 54 of the rack gear 50 in a case where the cam 70 is at the second position. In other words, the third cam surface 74A is positioned within the movement locus of the protrusions 53 and 54 in a case where the cam 70 is at the second position. The third cam surface 74A is configured to move the cam 70 from the second position toward the first position. Specifically, in a case where the rack gear 50 moves in the direction from the one end E10 of the casing 11 toward the other end E20 of the casing 11 in a state where the third cam surface 74A is in contact with the first protrusion 53 or the second protrusion 54, the third cam surface 74A causes the cam 70 to move from the second position toward the first position.
The third cam surface 74A is positioned downstream relative to the first cam surface 73A in the moving direction of the rack gear 50. The third cam surface 74A is positioned at a position different from the first cam surface 73A in a moving direction of the cam 70. Specifically, the first cam surface 73A is positioned farther away from the casing 11 than the third cam surface 74A is from the casing 11 in the axial direction.
The third cam surface 74A is inclined so that a downstream edge of the third cam surface 74A in the moving direction of the rack gear 50 is positioned farther away from the casing 11 than an upstream edge of the third cam surface 74A in the moving direction of the rack gear 50 is from the casing 11 in the axial direction. Specifically, the third cam surface 74A has a third edge E3, and a fourth edge E4. The fourth edge E4 is positioned farther away from the casing 11 than the third edge E3 is from the casing 11 in the axial direction. The third cam surface 74A is inclined so that the fourth edge E4 is positioned downstream relative to the third edge E3 in the moving direction of the rack gear 50.
The protruding portion 75 protrudes toward the developing electrode 20 from a portion of the base portion 71 farther from the casing 11. The protruding portion 75 protrudes toward the first cam portion 73 from one end of the base portion 71 farther from the casing 11 in the axial direction. The protruding portion 75 has a rectangular-shaped through-hole 75B penetrating the thickness of the protruding portion 75 in the axial direction.
Each of the second cam portions 76 protrudes toward the developing electrode 20 from a surface of the protruding portion 75 that faces the developing electrode 20. Hereinafter, the surface of the protruding portion 75 that faces the developing electrode 20 will also be referred to as “first surface 75A”. Each of the second cam portions 76 is positioned spaced apart from each other in the axial direction. Each of the second cam portions 76 is positioned away from one end and the other end of the protruding portion 75 in the axial direction. Each of the second cam portions 76 has a second cam surface 76A inclined relative to the axial direction, and a support surface 76B for supporting the developing electrode 20.
The second cam surface 76A is a surface for moving the developing electrode 20 in a direction away from the cam 70 in a case where the cam 70 moves from the first position to the second position. In a case where the cam 70 moves from the first position to the second position, the second cam surface 76A contacts the developing electrode 20. The direction away from the cam 70 is a direction different from the moving direction of the rack gear 50 and the moving direction of the cam 70. The second cam surface 76A is movable together with the first cam surface 73A. The second cam surface 76A is positioned farther away from the casing 11 than the first cam surface 73A is from the casing 11 in the axial direction.
The second cam surface 76A is inclined toward the first cam surface 75A. A downstream edge of the second cam surface 76A in the direction away from the casing 11 in the axial direction is positioned closer to the first surface 75A than an upstream edge of the second cam surface 76A in the direction away from the casing 11 in the axial direction is to the first surface 75A. Specifically, the second cam surface 76A has a fifth edge E5, and a sixth edge E6. The sixth edge E6 is positioned farther away from the casing 11 than the fifth edge E5 is from the casing 11 in the axial direction. The second cam surface 76A is inclined so as to protrude toward the developing electrode 20 in a direction from the sixth edge E6 toward the fifth edge E5. In other words, the second cam surface 76A is inclined so as to protrude toward the opening 62A in the direction from the sixth edge E6 toward the fifth edge E5. The support surface 76B extends parallel with the first surface 75A.
Referring back to
The electrode portion 21 is positioned so as to protrude through the opening 62A of the second cover portion 62 in the direction away from the cam 70 (see
The electrode portion 21 has a surface opposite to a surface of the electrode portion 21 facing the cam 70. Hereinafter, the surface of the electrode portion 21 opposite to the surface of the electrode portion 21 facing the cam 70 will also be referred to as “second surface 21A”. The second surface 21A is an arcuate curved surface that protrudes in the direction away from the cam 70 in a cross-section orthogonal to the axial direction. The electrode portion 21 has two recessed portions 24 into which the two second cam portions 76 of the cam 70 can enter, respectively. The recessed portions 24 are configured to be recessed from the surface of the electrode portion 21 facing the cam 70 in the direction away from the cam 70. Each of the recessed portions 24 has a fourth cam surface 24A contacting the second cam surface 76A of the second cam portion 76, and a bottom surface 24B extending parallel with the first surface 75A. The fourth cam surface 24A extends parallel with the second cam surface 76A.
Of the surface of the electrode portion 21 facing the cam 70, a portion positioned between the two recessed portions 24 serves as a supported surface 21B. In a case where the developing electrode 20 is at the fourth position, the supported surface 21B is supported at one of the second cam portions 76 of the cam 70 closer to the casing 11. Further, a surface of the first flange portion 22 facing the cam 70 serves as a supported surface 22A. In a case where the developing electrode 20 is at the fourth position, the supported surface 22A is supported at the other of the second cam portions 76 of the cam 70 positioned farther from the casing 11. Incidentally, in a case where the developing electrode 20 is at the third position, at least one of the surfaces of the developing electrode 20 facing the cam 70 (i.e. the surfaces including the supported surfaces 21B and 22A) and the bottom surface 24B of each recessed portions 24 may be supported by the cam 70.
As illustrated in
More specifically, the compression coil spring SP is in contact with a surface of the electrode portion 21 closer to the casing 11. Accordingly, in a case where the developing electrode 20 is at the third position, in a case where the developing electrode 20 moves from the third position to the fourth position, and in a case where the developing electrode 20 is at the fourth position, the compression coil spring SP keeps in contact with the electrode portion 21. That is, the developing electrode 20 is movable while the developing electrode 20 is in contact with the compression coil spring SP.
The compression coil spring SP has a length in a case where the one end of the compression coil spring SP is in contact with the developing electrode 20 and the other end of the compression coil spring SP is in contact with the bearing 40, and a natural length. The length is shorter than the natural length. Further, the compression coil spring SP is positioned opposite to the cam 70 with respect to the rack gear 50. The compression coil spring SP is positioned between the first guide portion 44 and the second guide portion 11C in the direction from the one end E10 of the casing 11 toward the other end E20 of the casing 11.
Next, operations and effects of each member constituting the developing cartridge 1 will be described in detail. In a case where the developing cartridge 1 is in a brand-new state, the rack gear 50 is positioned at a position closest to the one end E10 of the casing 11, and the cam 70 is positioned at a position closest to the casing 11. With this arrangement, the developing electrode 20 is placed at the third position.
As illustrated in
Thereafter, as a driving force is inputted from a driving source (not illustrated) at the main body casing to the coupling 13 of the developing cartridge 1, the driving force is transmitted to the shaft 14A of the agitator 14 through the coupling 13 and the gear mechanism (not illustrated). The driving force transmitted to the shaft 14A of the agitator 14 is transmitted to the agitator gear 31 as illustrated in
As the agitator gear 31 to which the driving force is transmitted rotates, the rack gear 50 moves in the direction from the one end E10 of the casing 11 toward the other end E20 of the casing 11. As illustrated in the sequence of
In a case where the cam 70 moves in the direction away from the casing 11 in the axial direction, as illustrated in the sequence of
In a case where the developing electrode 20 moves to the fourth position, the actuator AC is pushed upward by the developing electrode 20 and changed its position. That is, the cam 70 applies a force to the actuator AC through the developing electrode 20, thereby changing the position of the actuator AC in one direction. Accordingly, the optical sensor detects the change in position of the actuator AC in the one direction. A control device of the image forming apparatus can determine that the developing cartridge 1 is a brand-new cartridge, by detecting the change in position of the actuator AC using the optical sensor.
As illustrated in the sequence of
Thereafter, as illustrated in the sequence of
After the second protrusion 54 separates from the third cam surface 74A as illustrated in
According to the above, the following effects can be obtained in this embodiment.
Since the rack gear 50 moves in the direction from the one end E10 of the casing 11 toward the other end E20 of the casing 11, meshing between the rack gear 50 and the agitator gear 31 can be released.
Since the developing electrode 20 is formed of an electrically-conductive resin, the shape of the developing electrode 20 can be easily formed.
Next, a developing cartridge 101 according to a second embodiment will be described with reference to
In the first embodiment, the compression coil spring SP is configured as a component separate from the developing electrode 20. However, in the second embodiment, a spring and the developing electrode 20 are integrally configured as illustrated in
The protrusion 77 protrudes toward the spring electrode 80 from the end portion of the base portion 71 closer to the casing 11. The protrusion 77 has a semi-circular columnar shape. A surface of the protrusion 77 farther from the casing 11 is an arcuate curved surface that protrudes in the direction away from the casing 11 in the axial direction.
The spring support portion 78 protrudes toward the spring electrode 80 from the first surface 75A of the protruding portion 75. The spring support portion 78 has a surface facing the spring electrode 80. The surface of the spring support portion 78 includes a first flat surface 78A, a second flat surface 78B, and an inclined surface 78C. The inclined surface 78C connects the first flat surface 78A and the second flat surface 78B. The first flat surface 78A and the second flat surface 78B extend parallel with the base portion 71. The first flat surface 78A is positioned farther from the base portion 71 than the second flat surface 78B is from the base portion 71. The first flat surface 78A is positioned closer to the casing 11 than the second flat surface 78B is to the casing 11. The inclined surface 78C extends from an edge of the first flat surface 78A farther from the casing 11. The inclined surface 78C is connected to an edge of the second flat surface 78B closer to the casing 11. The inclined surface 78C is inclined so that a downstream edge of the inclined surface 78C in the direction away from the casing 11 in the axial direction is positioned closer to the base portion 71 than an upstream edge of the inclined surface 78C in the direction away from the casing 11 in the axial direction is to the base portion 71.
The spring support portion 78 has a recessed portion 78D. The recessed portion 78D is recessed toward the base portion 71 in a center portion of each of the surfaces 78A, 78B, and 78Cin, where the center portion of each of the surfaces 78A, 78B, 78C is defined relative to the direction from the one end E10 of the casing 11 toward the other end E20 of the casing 11. The recessed portion 78D is positioned between an edge of the first flat surface 78A closer to the casing 11 and an edge of the second flat surface 78B farther from the casing 11. Further, the spring support portion 78 has a side surface 78E closer to the casing 11. The spring support portion 78 includes an engagement claw 78F positioned at the side surface 78E and protruding from the side surface 78E.
The through-hole 63A of the third cover portion 63 of the gear cover 60 is formed to have a size corresponding to the spring electrode 80.
The spring electrode 80 is made of an electrically-conductive material. The spring electrode 80 is electrically connected to the developing roller 12. The spring electrode 80 is movable together with the cam 170. The spring electrode 80 includes a developing electrode 81 and a spring 82. The developing electrode 81 has a shape in conformance with the shape of the spring support portion 78. The spring 82 is formed integrally with the developing electrode 81.
The developing electrode 81 includes a first plate-like portion 81A, a second plate-like portion 81B, a third plate-like portion 81C, a fourth plate-like portion 81D, and a fifth plate-like portion 81E. The first plate-like portion 81A and the second plate-like portion 81B extend parallel with the base portion 71. The third plate-like portion 81C connects the first plate-like portion 81A and the second plate-like portion 81B. The fourth plate-like portion 81D extends from an end of the first plate-like portion 81A closer to the casing 11 toward the base portion 71. The fifth plate-like portion 81E extends from an end of the second plate-like portion 81B farther from the casing 11 toward the base portion 71.
The first plate-like portion 81A, the second plate-like portion 81B, and the third plate-like portion 81C are received by the recessed portion 78D of the spring support portion 78 and are positioned at a bottom surface of the recessed portion 78D.
In a state where the first plate-like portion 81A is positioned at the bottom surface of the recessed portion 78D, a surface of the first plate-like portion 81A opposite to a surface thereof facing the cam 170 is flush with the first flat surface 78A of the spring support portion 78. In a state where the second plate-like portion 81B is positioned at the bottom surface of the recessed portion 78D, a surface of the second plate-like portion 81B opposite to a surface thereof facing the cam 170 is flush with the second flat surface 78B of the spring support portion 78. In a state where the third plate-like portion 81C is positioned at the bottom surface of the recessed portion 78D, a surface of the third plate-like portion 81C opposite to a surface thereof facing the cam 170 is flush with the inclined surface 78C of the spring support portion 78.
Alternatively, in a state where the first plate-like portion 81A is positioned at the bottom surface of the recessed portion 78D, the surface of the first plate-like portion 81A opposite to the surface thereof facing the cam 170 is positioned farther from the base portion 71 than the first flat surface 78A of the spring support portion 78. In a state where the second plate-like portion 81B is positioned at the bottom surface of the recessed portion 78D, the surface of the second plate-like portion 81B opposite to the surface thereof facing the cam 170 is positioned farther from the base portion 71 than the second flat surface 78B of the spring support portion 78. In a state where the third plate-like portion 81C is positioned at the bottom surface of the recessed portion 78D, the surface of the third plate-like portion 81C opposite to the surface thereof facing the cam 170 is positioned farther from the base portion 71 than the inclined surface 78C of the spring support portion 78. Further, the surface of the third plate-like portion 81C inclined relative to the axial direction and opposite to the surface thereof facing the cam 170 serves as a second cam surface 81G.
The second cam surface 81G has a fifth edge E105, and a sixth edge E106. The sixth edge E106 is positioned farther away from the casing 11 than the fifth edge E105 is from the casing 11 in the axial direction. The second cam surface 81G is inclined so as to protrude toward the opening 62A in a direction from the sixth edge E106 toward the fifth edge E105.
The fourth plate-like portion 81D and the fifth plate-like portion 81E interpose the spring support portion 78 therebetween in the axial direction. An engagement hole 81F engages with the engagement claw 78F of the spring support portion 78. The fourth plate-like portion 81D has the engagement hole 81F.
The spring 82 includes a flat plate-like portion 82A, a first curved portion 82B, and a second curved portion 82C. The flat plate-like portion 82A extends parallel with the first plate-like portion 81A. The first curved portion 82B is curved so as to protrude away from the cam 170. The second curved portion 82C is curved so as to protrude toward the casing 11. The flat plate-like portion 82A extends toward the casing 11 from an end of the fourth plate-like portion 81D closer to the cam 170. The first curved portion 82B is connected to an end of the flat plate-like portion 82A closer to the casing 11. The second curved portion 82C extends from an end of the first curved portion 82B closer to the casing 11 in a direction away from the cam 170.
As illustrated in
As illustrated in
The cam portion 55 protrudes from the main body portion 51. A surface of the cam portion 55 closer to the casing 11 includes a first holding surface 55A, a second holding surface 55B, a third holding surface 55C, a connecting surface 55D, and a cam surface 55E. The first holding surface 55A, the second holding surface 55B, and the third holding surface 55C are planer surfaces orthogonal to the axial direction. The connecting surface 55D connects the first holding surface 55A and the second holding surface 55B. The cam surface 55E connects the second holding surface 55B and the third holding surface 55C.
The first holding surface 55A and the third holding surface 55C are positioned at positions the same as each other in the axial direction. The first holding surface 55A is positioned downstream relative to the third holding surface 55C. The first holding surface 55A and the third holding surface 55C come into contact with the protrusion 77 to hold the cam 170 at the initial position (first position).
The second holding surface 55B is positioned between the first holding surface 55A and the third holding surface 55C in the moving direction of the rack gear 150. The second holding surface 55B is positioned farther away from the casing 11 than the first holding surface 55A is from the casing 11 (see
The connecting surface 55D extends from an upstream edge of the first holding surface 55A and is connected to a downstream edge of the second holding surface 55B. The connecting surface 55D is inclined so that an upstream edge of the connecting surface 55D is positioned farther away from the casing 11 than a downstream edge of the connecting surface 55D is from the casing 11.
The cam surface 55E is inclined relative to the moving direction of the rack gear 150. Specifically, the cam surface 55E extends from an upstream edge of the second holding surface 55B and is connected to a downstream edge of the third holding surface 55C. The cam surface 55E is inclined so that an upstream edge of the cam surface 55E is positioned closer to the casing 11 than a downstream edge of the cam surface 55E is to the casing 11.
In this embodiment, as illustrated in
In a case where the developing cartridge 1 is attached to the main body casing of the image forming apparatus in a state where the cam 170 is at the initial position, the actuator AC is pushed by the second plate-like portion 81B of the spring electrode 80 supported at the cam 170 as illustrated in
Thereafter, as illustrated in the sequence of
While the cam 170 moves from the initial position to the outside position, the actuator AC is pushed by the inclined third plate-like portion 81C of the spring electrode 80 supported at the cam 170 as illustrated in
Thereafter, as illustrated in the sequence of
As described above, in the second embodiment, similarly to the first embodiment, meshing between the rack gear 150 and the agitator gear 31 can be released since the rack gear 150 moves in the direction from the one end E10 of the casing 11 toward the other end E20 of the casing 11. Further, in the second embodiment, since the spring 82 and the developing electrode 81 are configured as a single component (spring electrode 80), the number of components can be reduced. The spring and the developing electrode may be separate components. Further, the spring as a separate component may be a coil spring or a wire spring.
<Modifications>
While the description has been made in detail with reference to the embodiments thereof, it would be apparent to those skilled in the art that many modifications and variations may be made therein without departing from the scope of the disclosure.
In the first embodiment, the fourth cam surfaces 24A are provided at the developing electrode 20, and the second cam surfaces 76A are provided at the cam 70. However, for example, a protrusion engaging with the second cam surface of the cam may be provided at the developing electrode.
In the first embodiment, the rack gear 50 in its entirety is covered with the gear cover 60. However, the gear cover may cover a portion of the rack gear and may expose the remaining portion of the rack gear to outside.
In the first and second embodiments, the agitator gear 31 is exemplified as an example of a gear. However, any gears other than the agitator gear 31 may be available.
In the first and second embodiment, the compression coil spring SP and the spring 82 are exemplified as a spring. However, the spring may be, for example, a wire spring or a torsion spring.
In the first embodiment, the cam 70 is movably supported at the gear cover 60. However, the cam may be movably supported at the casing.
Further, the respective elements described in the above embodiments and modifications may be arbitrarily combined and implemented.
Number | Date | Country | Kind |
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2016-256106 | Dec 2016 | JP | national |
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Number | Date | Country |
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201229469 | Apr 2009 | CN |
2011-215374 | Oct 2011 | JP |
2013-037098 | Feb 2013 | JP |
2013-037098 | Feb 2013 | JP |
2013-054053 | Mar 2013 | JP |
WO-2014141444 | Sep 2014 | WO |
Entry |
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English translation of CN-201229469-Y retrieved from EPO's Espacenet website. |
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Notification of First Office Action with Search Report issued in corresponding Chinese Patent Application No. 201710873925.0; dated May 26, 2021. |
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Number | Date | Country | |
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Parent | 15715979 | Sep 2017 | US |
Child | 16988029 | US |