CN220752530U - Drum box - Google Patents

Abstract

There is provided a drum cartridge comprising: a photosensitive drum that rotates about a drum axis extending in a first direction; and a charger for charging the photosensitive drum, including a cable extending in a first direction, a grid, and a charging frame. The grid electrode comprises: a first plate, which is positioned between the photosensitive drum and the cable, is opposite to the photosensitive drum and is provided with a plurality of grid holes; a second plate extending from one end of the first plate in a direction away from the photosensitive drum, the third direction being perpendicular to the first direction and a second direction in which the photosensitive drums are arranged with the cable; and a third plate extending from the other end of the first plate in the third direction to a direction away from the photosensitive drum. The second plate has a first end connected to the first plate and an opposite second end. The third plate has a third end connected to the first plate and a fourth end on the opposite side. The charging frame comprises: a first face opposite the second end; a first protrusion protruding from the first surface toward the photosensitive drum, in contact with the second end; a second face opposite the fourth end; and a second protrusion protruding from the second surface toward the photosensitive drum and contacting the fourth end.

Description

Drum box

Technical Field

The utility model relates to a drum cartridge comprising a charger with a cable and a grid.

Background

A drum cartridge having a charger having a cable and a grid is known (see patent document 1). The corona discharge is generated by applying a voltage to the cable, and the charger charges the surface of the corresponding photosensitive drum.

Patent document 1: japanese patent application laid-open No. 2010-197969

Disclosure of Invention

The drum cartridge has a cable, a grid, and a charging frame. The charging frame holds the cable and the grid. However, the charged frame is likely to be deformed.

In view of the above, an object of the present utility model is to suppress deformation of a charging frame of a charger.

(1) In order to solve the above-described problems, the present utility model provides a drum cartridge comprising: a photosensitive drum rotatable about a drum axis extending in a first direction; and a charger for charging the photosensitive drum, the charger including a cable extending in the first direction, a grid, and a charging frame. The gate electrode includes: a first plate located between the photosensitive drum and the cable, opposite to the photosensitive drum, having a plurality of gate holes; a second plate extending from one end of the first plate in a third direction, which is perpendicular to the first direction and a second direction, to a direction away from the photosensitive drum, the second direction being a direction in which the photosensitive drum and the cable are arranged; and a third plate extending from the other end of the first plate in the third direction in a direction away from the photosensitive drum. The second plate has a first end connected to the first plate and a second end located on an opposite side from the first end. The third plate has a third end connected to the first plate and a fourth end located on an opposite side from the third end. The charging frame comprises: a first face opposite the second end; a first protrusion protruding from the first surface toward the photosensitive drum, in contact with the second end; a second face opposite the fourth end; and a second protrusion protruding from the second surface toward the photosensitive drum, in contact with the fourth end.

According to the drum cartridge described above, since the first protrusion is in contact with the second end of the second plate of the grid, and the second protrusion is in contact with the fourth end of the third plate of the grid, deformation of the charging frame can be suppressed.

(2) In the drum cartridge of the present utility model, the first projection is located closer to a center of the second plate in the first direction than one end of the second plate in the first direction, and is located closer to a center of the second plate in the first direction than the other end of the second plate in the first direction.

According to the drum cartridge described above, since the first projection is located near the center in the first direction, deformation of the center portion in the first direction of the charging frame can be suppressed.

(3) In the drum cartridge of the present utility model, the charging frame may have a plurality of the first protrusions, and the plurality of the first protrusions may be arranged symmetrically with respect to a center of the second plate in the first direction.

(4) In the drum cartridge of the present utility model, the second projection is located closer to the center of the third plate in the first direction than one end of the third plate in the first direction, and closer to the center of the third plate in the first direction than the other end of the third plate in the first direction.

According to the drum cartridge described above, since the second projection is located near the center in the first direction, the deformation of the center portion of the gate in the first direction can be suppressed.

(5) In the drum cartridge of the present utility model, the charging frame may include a plurality of the second protrusions, and the plurality of the second protrusions may be arranged symmetrically with respect to a center of the third plate in the first direction.

(6) In the drum cartridge of the present utility model, the charger further includes a cleaner for cleaning the cable, the cleaner being slidable between one end portion and the other end portion of the cable. The charging frame includes: a first rail extending in the first direction and engaged with the cleaner to hold the cleaner slidably; and a second rail extending in the first direction, cooperating with the cleaner, holding the cleaner slidably, the cleaner being held between the first rail and the second rail. The first guide rail has a first rib extending in the first direction and protruding toward the photosensitive drum. The second guide rail has a second rib extending in the first direction and protruding toward the photosensitive drum. At least a portion of the cable is located between the first rib and the second rib.

According to the drum cartridge described above, the first rib and the second rib are positioned with high accuracy in the first direction with respect to the position of the cable extending in the first direction. As a result, charging unevenness of the photosensitive drum in the first direction can be suppressed.

(7) The drum cartridge of the present utility model, the charging frame includes: a first contact portion that contacts an end portion of the grid electrode in the first direction and contacts the grid electrode from the photosensitive drum side in the second direction; and a second contact portion that contacts the other end portion of the grid electrode in the first direction and contacts the grid electrode from the photosensitive drum side in the second direction.

(8) In the drum cartridge of the present utility model, the gate is located between the first protrusion and the second protrusion and the first contact portion and the second contact portion.

According to the drum cartridge described above, the positioning of the charging frame and the grid is stabilized by positioning the grid between the first projection and the second projection and the first contact portion and the second contact portion.

The utility model provides a drum box capable of inhibiting deformation of a charging frame of a charger.

Drawings

Fig. 1 is a cross-sectional view of an image forming apparatus according to an embodiment.

Fig. 2 is an enlarged cross-sectional view showing the structure of the drum cartridge.

Fig. 3 is a perspective view of the drum cartridge.

Fig. 4 is an exploded perspective view of the drum cartridge.

Fig. 5 is a sectional view showing the charger and the peripheral structure of the charger.

Fig. 6 (a) is a perspective view of the other side of the first direction of the gate electrode, and (b) is a perspective view of the one side of the first direction of the gate electrode.

Fig. 7 (a) is a diagram illustrating the other side of the first direction of the holding gate, and (b) is a diagram illustrating the one side of the first direction of the holding gate.

Fig. 8 is a view showing three first protrusions located in the charging frame body in contact with the gate electrode.

Fig. 9 is a view of the gate from above, and shows the positional relationship between the protrusions of the charging frame and the gate.

Fig. 10 is a sectional view showing a positional relationship of the developing pressing member and the holding portion.

Fig. 11 (a) is a perspective view of the developing pressing member, and (b) is a perspective view of the holding portion.

Fig. 12 (a) is a perspective view showing the connection portion between the charging frame and the drum frame before connection, and (b) is a perspective view showing the connection portion after connection.

Fig. 13 (a) is a perspective view showing a state before connection of the connection portion between the charging frame and the drum frame, as viewed from a direction different from that of fig. 12, and (b) is a perspective view after connection.

Fig. 14 (a) is a sectional view A-A in fig. 12 (B), and (B) is a sectional view B-B.

Detailed Description

Embodiments of the present utility model will be described in detail below with reference to the accompanying drawings as appropriate. In the following description, the axial direction of the photosensitive drum 51 is referred to as a first direction. Further, the direction in which the photosensitive drum 51 and the cable 110 are aligned is referred to as a second direction. In addition, a direction perpendicular to the first direction and the second direction is referred to as a third direction. The arrows in the drawings indicate the respective directions, and refer to "one side" of the respective directions.

As shown in fig. 1, the image forming apparatus 1 is a color printer. The image forming apparatus 1 includes an apparatus body 10, a cover 11, a paper feed portion 20, an image forming portion 30, and a paper discharge portion 90.

The cover 11 is located at an upper portion of the apparatus body 10. The cover 11 rotates with respect to the apparatus body 10 about the rotation shaft 12, thereby opening and closing an opening 10A formed in the upper surface of the apparatus body 10.

The paper feed portion 20 is located at a lower portion in the apparatus body 10. The sheet feeding section 20 includes a sheet feeding tray 21 and a sheet feeding mechanism 22. The sheets S in the sheet feed tray 21 are separated one by the sheet feeding mechanism 22 and fed to the image forming portion 30.

The image forming section 30 includes four LED units 40, four drum cartridges 50, a transfer unit 70, and a fixing unit 80.

The LED unit 40 is swingably supported by the cover 11 via the holding portion 14. In a state where the cover 11 is closed, the LED unit 40 faces the photosensitive drum 51. The LED unit 40 emits light based on image data by a light emitting portion (LED) at the head end, and exposes the surface of the charged photosensitive drum 51.

The drum cartridge 50 is located between the cover 11 and the sheet feed tray 21. The drum cartridge 50 can be mounted and dismounted through the opening 10A of the apparatus body 10.

As shown in fig. 2, the drum cartridge 50 includes a drum frame DF, a photosensitive drum 51, a charger 52, a cleaning roller 57, and a developing cartridge 60.

The drum cartridges 50 are indicated by symbols of 50K, 50Y, 50M, 50C containing toners for black, yellow, magenta, and cyan, respectively, and are arranged in order.

The drum frame DF holds the photosensitive drum 51. The photosensitive drum 51 is rotatable about a drum axis 51X extending in the first direction. The photosensitive drum 51 is rotatably held by the drum frame DF.

The charger 52 is provided corresponding to each photosensitive drum 51. The charger 52 charges the surface of the corresponding photosensitive drum 51 by applying a cable voltage to the cable 110 to generate corona discharge. The structure of the charger 52 will be described later.

Returning to fig. 2, a cleaning roller 57 is provided corresponding to each photosensitive drum 51. The cleaning roller 57 contacts the photosensitive drum 51 to remove paper dust, toner, and the like on the photosensitive drum 51.

The developing cartridge 60 includes a developing roller 63, a supply roller 64, a layer thickness regulating blade 65, and a toner accommodating portion 66. The developing roller 63 is provided corresponding to each photosensitive drum 51. The developing roller 63 carries toner on the surface. In the present embodiment, the developing cartridge 60 can be attached to the drum cartridge 50 and detached from the drum cartridge 50. The developing cartridge 60 can be mounted and dismounted with respect to the apparatus body 10 in a state of being mounted on the drum cartridge 50.

As shown in fig. 1, the transfer unit 70 is located between the paper feed tray 21 and the drum cartridge 50. The transfer unit 70 includes a driving roller 71, a driven roller 72, a conveying belt 73, and four transfer rollers 74. The conveyor belt 73 is an endless belt stretched between a driving roller 71 and a driven roller 72. The outer surface of the conveyor belt 73 contacts the photosensitive drum 51. The transfer roller 74 is located inside the conveying belt 73.

The fixing unit 80 is located on the downstream side of the drum cartridge 50 and the transfer unit 70 in the conveyance direction of the sheet S. The fixing unit 80 includes a heating roller 81 and a pressing roller 82. The pressing roller 82 is located at a position opposite to the heating roller 81.

In the image forming section 30, after the surface of the photosensitive drum 51 is uniformly charged by the charger 52, the LED unit 40 exposes the surface to light, thereby forming an electrostatic latent image based on image data on the photosensitive drum 51.

The toner in the toner housing portion 66 is supplied to the developing roller 63 via the supply roller 64, enters between the developing roller 63 and the layer thickness regulating blade 65, and is carried on the developing roller 63 as a thin layer having a certain thickness.

Then, by supplying the toner carried on the developing roller 63 to the exposed portion of the photosensitive drum 51, the electrostatic latent image is visualized, forming a toner image on the photosensitive drum 51. After that, the sheet S fed from the sheet feeding section 20 is conveyed between the photosensitive drum 51 and the conveying belt 73 and the transfer roller 74, whereby the toner image formed on the photosensitive drum 51 is transferred onto the sheet S. The sheet S to which the toner image is transferred is conveyed between the heating roller 81 and the pressing roller 82 to thermally fix the toner image.

The paper discharge portion 90 mainly includes a paper discharge path 91 for guiding the paper S conveyed out of the fixing unit 80 and a plurality of conveying rollers 92 for conveying the paper S. The sheet S having the thermally fixed toner image is conveyed to the sheet discharge path 91 by the conveying roller 92, discharged to the outside of the apparatus body 10, and placed on the sheet discharge tray 13.

Next, the structures of the drum cartridge 50 and the charger 52 will be described in detail. As shown in fig. 3 and 4, the charger 52 includes a cable 110, a grid 120, a charging frame 130, and a cleaner 140.

The cable 110 extends in a first direction, that is, in the axial direction of the photosensitive drum 51.

The grid 120 is an electrode located between the cable 110 and the photosensitive drum 51. The gate electrode 120 is made of metal and has a U-shape. The gate electrode 120 has a first plate 121, a second plate 122, and a third plate 123.

As shown in fig. 5, the first plate 121 is a flat plate located between the photosensitive drum 51 and the cable 110. The first plate 121 is opposed to the photosensitive drum 51. The first plate 121 has a plurality of gate holes 121H (see also (b) in fig. 6). The plurality of grid holes 121H extend in the first direction and are aligned in the third direction.

As shown in (a) and (B) of fig. 6, the first plate 121 has a first extension 121A, a second extension 121B, and a third extension 121C. As shown in fig. 6 (a), the first extension portion 121A is located at the other end of the first plate 121 in the first direction. The first extension 121A extends to the other side in the third direction. The second extension 121B is located at the other end of the first plate 121 in the first direction. The second extension 121B extends to one side in the third direction. As shown in (b) of fig. 6, the third extension portion 121C is located at one end of the first plate 121 in the first direction. The third extension 121C extends to the other side in the third direction.

As shown in fig. 5, the second plate 122 is a flat plate extending from one end of the first plate 121 in the third direction in a direction away from the photosensitive drum 51. The second plate 122 has a first end 122P connected to the first plate 121 and a second end 122Q located on the opposite side of the first end 122P.

As shown in (b) of fig. 6, the second plate 122 has a fourth extension 122A. The fourth extension 122A is located at one end of the second plate 122 in the first direction. The fourth extension 122A extends from one end of the second end 122Q of the second plate 122 in the first direction to the other side in the second direction, is bent in the third direction, and extends to one side in the third direction. Specifically, the fourth extension portion 122A extends from the second end 122Q to the other side in the second direction to the bent portion 122K, and extends from the bent portion 122K to the one side in the third direction to the head end of the second extension portion 122A.

The third plate 123 is a flat plate extending from the other end of the first plate 121 in the third direction in a direction away from the photosensitive drum 51. The third plate 123 has a third end 123P connected to the first plate 121 and a fourth end 123Q located on the opposite side of the third end 123P.

Referring back to fig. 4, the charging frame 130 is a resin frame extending elongated in the first direction. The charging frame 130 is mounted on the drum frame DF. The charging frame 130 supports the cable 110 and the grid 120. As shown in fig. 5, the charging frame 130 covers the cable 110 and the grid 120. Further, the charging frame 130 holds the cleaner 140 slidably.

The charging frame 130 has a cover wall 130W, a support arm 137, and a support arm 138. The cap wall 130W covers the gate 120 from the opposite side of the photosensitive drum 51 with respect to the gate 120.

As shown in fig. 7 (a), the support arm 137 extends from the end portion of the cover wall 130W on the other side in the first direction toward the photosensitive drum 51 side. The support arm 137 is provided with two. One of the support arms 137 extends from one of the first-direction-other-side ends of the cap wall 130W toward the photosensitive drum 51 side from one of the third-direction-side ends of the grid 120. The other of the support arms 137 extends from the end portion of the other of the first direction of the cap wall 130W, which is the other of the third direction of the grid 120, toward the photosensitive drum 51 side. The end of each support arm 137 on the second direction side has a first contact portion 133. Each of the first contact portions 133 has a support surface 133A facing the lid wall 130W side. Each supporting surface 133A contacts the first plate 121 of the grid electrode 120 from the photosensitive drum 51 side in the second direction to support the grid electrode 120.

As shown in fig. 7 (b), the support arm 138 extends from the end portion of the cover wall 130W on the first direction side toward the photosensitive drum 51 side. The support arm 138 is provided with one. The support arm 138 extends from the end portion of the other side of the grid 120 in the third direction toward the photosensitive drum 51 side. The end of the support arm 138 on the second direction side has a second contact portion 134. The second contact portion 134 has a support surface 134A facing the lid wall 130W side. The support surface 134A is in contact with the first plate 121 of the grid electrode 120 from the photosensitive drum 51 side in the second direction to support the grid electrode 120.

A second contact portion 134 is also provided at an end portion of the cover wall 130W on the first direction side and on the third direction side. The cover wall 130W has a first groove 134G extending from an end portion on one side in the second direction to the other side in the second direction and a second groove 134H extending from an end portion on the other side in the second direction of the first groove 134G to the other side in the first direction. By forming the second groove 134H, a surface facing the opposite side to the photosensitive drum 51 out of the surfaces constituting the second groove 134H constitutes the supporting surface 134A. The support surface 134A provided on the cap wall 130W is in contact with the fourth extension 122A of the grid electrode 120 from the photosensitive drum 51 side in the second direction to support the grid electrode 120.

As shown in fig. 5 and 7, the charging frame 130 further includes a first surface 131, a first protrusion 131T, a second surface 132, a second protrusion 132T, a first rail 135, and a second rail 136.

As shown in fig. 5, the first surface 131 is a surface of the cover wall 130W on the photosensitive drum 51 side. The first surface 131 is located on the third direction side of the cable 110. The first face 131 is opposite the second end 122Q of the second plate 122. The first face 131 is not in contact with the second end 122Q of the second plate 122.

The first projection 131T is a projection projecting from the first surface 131 toward the photosensitive drum 51. The first protrusion 131T contacts the second end 122Q of the second plate 122. As shown in fig. 8 and 9, the charging frame 130 has a plurality of first protrusions 131T. In the present embodiment, the charging frame 130 has three first protrusions 131T. The three first protrusions 131T are aligned in the first direction.

As shown in fig. 9, each first protrusion 131T is located closer to the first-direction center C3 of the second plate 122 than the first-direction one end C1 of the second plate 122. Further, each first protrusion 131T is located closer to the first-direction center C3 than the other end C2 of the second plate 122 in the first direction. The plurality of first protrusions 131T are symmetrically arranged with respect to the center C3 of the second plate 122 in the first direction. Specifically, the first protrusion 131T located in the center among the three first protrusions 131T is located in the center C3 of the second plate 122. The three first protrusions 131T are arranged equidistantly in the first direction.

As shown in fig. 5, the second surface 132 is a surface of the cap wall 130W on the photosensitive drum 51 side. The second face 132 is located on the other side in the third direction than the cable 110. The second face 132 is opposite the fourth end 123Q of the third plate 123. The second face 132 is not in contact with the fourth end 123Q of the third plate 123.

The second projection 132T is a projection projecting from the second surface 132 toward the photosensitive drum 51. The second protrusion 132T contacts the fourth end 123Q of the third plate 123. As shown in fig. 9, the charging frame 130 has a plurality of second protrusions 132T. In the present embodiment, the charging frame 130 has three second protrusions 132T. The three second protrusions 132T are aligned in the first direction.

Each of the second protrusions 132T is located closer to the first-direction center D3 of the third plate 123 than the first-direction one end D1 of the third plate 123. Further, each of the second protrusions 132T is located closer to the first-direction center D3 than the other end D2 of the third plate 123 in the first direction. The plurality of second protrusions 132T are symmetrically arranged with respect to the center D3 of the third plate 123 in the first direction. Specifically, the second protrusion 132T located in the center among the three second protrusions 132T is located in the center D3 of the third plate 123. The three second protrusions 132T are arranged equidistantly in the first direction.

As shown in (a) of fig. 7, the first contact portion 133 is a portion that contacts the other end portion of the gate electrode 120 in the first direction. The first contact portion 133 contacts the grid 120 from the photosensitive drum 51 side in the second direction. Specifically, the first contact portions 133 are arranged at two places in the third direction in contact with the first extending portions 121A and the second extending portions 121B of the first plate 121.

As shown in (b) of fig. 7, the second contact portion 134 is a portion that contacts one end portion of the gate electrode 120 in the first direction. The second contact portion 134 contacts the grid 120 from the photosensitive drum 51 side in the second direction. Specifically, the second contact portions 134 are arranged at two places in the third direction in contact with the third extension portion 121C of the first plate 121 and the fourth extension portion 122A of the second plate 122.

As described above, the gate electrode 120 is positioned on the charging frame 130 by being in contact with the three first protrusions 131T, the three second protrusions 132T, the two first contact portions 133, and the two second contact portions 134. As shown in fig. 5, the gate electrode 120 is located between the first and second protrusions 131T and 132T and the first and second contact portions 133 and 134 in the second direction. In the present embodiment, the gate electrode 120 is sandwiched by the first and second protrusions 131T and 132T and the first and second contact portions 133 and 134 in the second direction.

The first rail 135 is a rail extending in a first direction. The first rail 135 cooperates with the cleaner 140 to hold the cleaner 140 slidably. The first rail 135 has a first rib 135R.

The first rib 135R is a rib extending in the first direction. The first rib 135R protrudes toward the photosensitive drum 51.

The second rail 136 is a rail extending in the first direction. The second guide 136 cooperates with the cleaner 140 to hold the cleaner 140 slidably. The second rail 136 has a second rib 136R.

The second rib 136R is a rib extending in the first direction. The second rib 136R protrudes toward the photosensitive drum 51.

At least a portion of the cable 110 is located between the first rib 135R and the second rib 136R. The position of the cable 110 in the second direction overlaps the first rib 135R and the second rib 136R. In the present embodiment, the cable 110 is located between the first rib 135R and the second rib 136R. Specifically, the cable 110 is located between a line L1 connecting the end of the first rib 135R on the lid wall 130W side and the end of the second rib 136R on the lid wall 130W side and a line L2 connecting the head end of the first rib 135R and the head end of the second rib 136R. That is, the first rib 135R and the second rib 136R protrude further toward the photosensitive drum 51 side than the cable 110. In general, the ribs near the cable 110 do not protrude further toward the photosensitive drum 51 side than the cable 110, but if the first ribs 135R and the second ribs 136R protrude as described above, the electric field from the cable 110 to the gate 120 is susceptible to the first ribs 135R and the second ribs 136R.

As shown in fig. 3, the cleaner 140 is held by the charging frame 130 and is slidable in the first direction. That is, the cleaner 140 can slide between one end and the other end of the cable 110. The cleaner 140 moves while being in sliding contact with the cable 110, thereby cleaning the cable 110.

As shown in fig. 5, the cleaner 140 has a holding member 141 and a sponge 142.

The holding member 141 has a first groove 141A, a second groove 141B, and a sponge holding portion 141C. The first groove 141A is a groove extending in the first direction and recessed toward the other side in the third direction. The first groove 141A enters the first rail 135. The second groove 141B is a groove extending in the first direction and recessed to one side in the third direction. The second slot 141B enters the second rail 136. The holding member 141 is slidable in the first direction by the first groove 141A entering the first rail 135 and the second groove 141B entering the second rail 136. The sponge holding portion 141C is a concave portion concave to the other side in the second direction. The sponge holding portion 141C holds the sponge 142.

The sponge 142 holds the cable 110. In a state where the drum cartridge 50 is detached from the apparatus body 10, the user slides the cleaner 140, thereby cleaning the cable 110. If the surface of the cable 110 has an adherent substance, the adherent substance is removed by the cleaner 140.

As shown in fig. 3, the drum cartridge 50 has a development pressing member 210. The developing pressing member 210 is a member that presses the developing cartridge 60 in a state where the developing cartridge 60 is mounted on the drum cartridge 50. In the case where the developing cartridge 60 is pressed by the developing pressing member 210, the developing roller 63 is in contact with the photosensitive drum 51 (see also fig. 2).

As shown in fig. 10, the developing pressing member 210 is held on the holding portion 220. The holding portion 220 is slidably supported by the drum frame DF by being biased by a spring 230. When the developing cartridge 60 is mounted on the drum cartridge 50, the developing pressing member 210 presses the developing cartridge 60 and contacts the developing electrode 240.

As shown in (a) of fig. 11, the developing pressing member 210 is composed of a conductive resin. The developing pressing member 210 has a pressing portion 211, an electrode contact portion 212, a cylindrical portion 213, a flange portion 214, and a groove portion 215.

The pressing portion 211 is a portion that presses the developing cartridge 60 in a state where the developing cartridge 60 is mounted on the drum cartridge 50. The pressing portion 211 is flat. The cylindrical portion 213 extends in a substantially cylindrical shape from a central portion of the pressing portion 211. The flange portion 214 is located at a head end of the cylindrical portion 213 remote from the pressing portion 211. The flange 214 is conical. The flange portion 214 has a protrusion 214A. The projection 214A is located on the pressing portion 211 side surface of the flange portion 214. The projection 214A has a slope surface which is closer to the pressing portion 211 side as it is radially outward of the cylindrical portion 213.

The groove portion 215 extends over the entire circumference of the cylindrical portion 213 between the cylindrical portion 213 and the flange portion 214.

The electrode contact portion 212 extends from one end of the pressing portion 211. The electrode contact portion 212 is a portion in contact with the developing electrode 240, and has a slope 212A in contact with the developing electrode 240 when the developing cartridge 60 is mounted on the drum cartridge 50. The inclined surface 212A is inclined with respect to the axial direction of the cylindrical portion 213.

As shown in fig. 11 (b), the holding portion 220 has a base portion 228, a cylindrical portion 221, and a hook 222.

The base 228 is flat. The cylindrical portion 221 extends from the base portion 228. The cylindrical portion 221 has a cylindrical shape. The hole 221A inside the cylindrical portion 221 is entered from the base portion 228 side by the cylindrical portion 213 of the developing pressing member 210. The cylindrical portion 221 has a first groove 223 and a second groove 224. The first groove 223 and the second groove 224 extend in the axial direction of the cylindrical portion 221. The hook 222 is located between the first groove 223 and the second groove 224. The hooks 222 are able to flex relative to the other portions of the cylindrical portion 221. The hook 222 has a claw 222A. The head end of the claw 222A, which is remote from the base portion 228, protrudes toward the center of the cylindrical portion 221. The head end surface 222B of the claw 222A is inclined so as to be closer to the base portion 228 as it is radially outward of the tubular portion 221. The claw 222A is a release preventing member that holds the cylindrical portion 213 from being pulled out from the holding portion 220 by entering the groove portion 215 of the development pressing member 210.

In a state where the developing pressing member 210 is combined with the holding portion 220, the cylindrical portion 221 enters the inside of the compression coil spring 230. The pressing portion 211 of the developing pressing member 210 is pressed against the developing cartridge 60, not shown in the drawings, by the urging force of the compression coil spring 230.

When the developing pressing member 210 is mounted on the holding portion 220, the cylindrical portion 213 enters the inside of the cylindrical portion 221, and the head end 222A of the hook portion 222 enters the groove portion 215. At this time, the inclined surface of the projection 214A is located at a position close to and opposite to the inclined surface of the claw 222A of the holding portion 220. Therefore, the flange 214 is not easily pulled out from the holding portion 220 by the protrusion 214A being caught by the claw 222A.

As described above, the charging frame 130 is mounted on the drum frame DF. As shown in fig. 4, one end of the charging frame 130 in the first direction has a first connecting portion 310 for connecting with the drum frame DF. The drum frame DF has a second coupling portion 320 at one end in the first direction for coupling with the charging frame 130. As shown in fig. 3, the first connecting portion 310 of the charging frame 130 is connected to the second connecting portion 320 of the drum frame DF.

As shown in fig. 12 (a) and 13 (a), the first connecting portion 310 has an arm shape extending toward the second connecting portion 320. The first coupling part 310 has a first hook 311, a second hook 312, and a rib 313 at a head end portion of the arm.

The first hook 311 is a hook protruding to one side in the first direction. The first hook 311 hooks the second coupling portion 320 from the other side in the first direction.

The second hook 312 is located on the first direction side of the first hook 311. Further, the second hook 312 is located further to one side in the second direction and to the other side in the third direction than the first hook 311. The second hook 312 is a hook protruding to the other side in the first direction. The second hook 312 hooks the second coupling portion 320 from the first direction side.

The rib 313 is located between the first hook 311 and the second hook 312 in the third direction. The rib 313 is a rib protruding to the other side in the first direction and extending in the second direction.

The second coupling portion 320 has a plate shape. The second coupling portion 320 has a first recess 321, a second recess 322, and a slit 323.

The first concave portion 321 is located on the surface of the second coupling portion 320 on the other side in the first direction. The first recess 321 is a recess recessed toward one side in the first direction.

The second concave portion 322 is located on a surface of the second coupling portion 320 on the first direction side. The second recess 322 is a recess recessed toward the other side in the first direction. The second concave portion 322 is located on one side in the second direction and on the other side in the third direction than the first concave portion 321.

The slit 323 is located between the first recess 321 and the second recess 322 in the third direction. The slit 323 is a slit extending in the second direction and penetrating in the first direction.

As shown in fig. 12 (b), fig. 13 (b), and fig. 14 (a), when the first coupling portion 310 and the second coupling portion 320 are coupled, the first hook 311 enters the first recess 321. Further, as shown in (b) of fig. 14, in the case of coupling the first coupling portion 310 and the second coupling portion 320, the second hook 312 enters the second recess 322. As shown in fig. 12 (b) and 13 (b), when the first connecting portion 310 and the second connecting portion 320 are connected, the rib 313 enters the slit 323. As a result, the first hooks 311 and the second hooks 312 are hardly offset in the third direction by the rib 313 entering the slit 323. The second coupling portion 320 is hooked on the first hook 311 from the other side in the first direction, and is hooked on the second hook 312 from the one side in the first direction. In this way, since the two hooks sandwich the second coupling portion 320 from both sides in the first direction, the first coupling portion 310 and the second coupling portion 320 are not easily separated.

According to the image forming apparatus 1 described above, the following effects can be achieved.

The charging frame 130 is a resin frame that extends long and thin in the first direction for the purpose of being small in size and light in weight. Further, the charging frame 130 covers the cable 110 and the grid 120, and holds the cleaner 140 to be slidable, and thus is easily deformed in the first direction. However, according to the image forming apparatus 1 of the present embodiment, the first protrusion 131T of the charging frame 130 is in contact with the second end 122Q of the second plate 122 of the gate electrode 120, and the second protrusion 132T of the charging frame 130 is in contact with the fourth end 123Q of the third plate 123 of the gate electrode 120. Therefore, even if the cover wall 130W of the charging frame 130 is deflected toward the photosensitive drum 51, the cover wall 130W can be supported by the grid 120, and deformation of the grid can be suppressed.

Further, the first protrusion 131T of the charging frame 130 is located closer to the first-direction center C3 of the second plate 122 than the first-direction one end C1 of the second plate 122, and is located closer to the first-direction center C3 of the second plate 122 than the first-direction other end C2 of the second plate 122. Therefore, deformation of the first-direction central portion of the lid wall 130W can be suppressed.

Further, the second protrusion 132T of the charging frame 130 is located closer to the first-direction center D3 of the third plate 123 than the first-direction one end D1 of the third plate 123, and is located closer to the first-direction center C3 of the third plate 123 than the first-direction other end D2 of the third plate 123. Therefore, deformation of the first-direction central portion of the lid wall 130W can be suppressed.

In addition, at least a portion of the cable 110 is located between the first rib 135R and the second rib 136R. In the present embodiment, the cable 110 is located between the first rib 135R and the second rib 136R, overlapping the first rib 135R and the second rib 136R at a position in the second direction. Therefore, the electric field is more directed toward the photosensitive drum 51 than in the case where the cable 110 does not overlap the first rib 135R and the second rib 136R in the second direction. Therefore, the charger 52 can charge the photosensitive drum 51 with a smaller current value than in the case where the cable 110 does not overlap the first rib 135R and the second rib 136R in the second direction.

In this case, the discharge from the cable 110 to the gate electrode 120 is easily affected by the positions of the first rib 135R and the second rib 136R. Assuming that the charging frame 130 is deformed by deflection in the first direction, the positional relationship of the cable 110 with the first rib 135R and the second rib 136R in the second direction changes according to the position in the first direction. Therefore, an error in the vertical positional relationship of the cable 110 with the first rib 135R and the second rib 136R easily causes a deviation in the surface potential of the photosensitive drum 51. However, in the charging frame 130 of the present embodiment, since deformation of the cover wall 130W in the first direction is suppressed, the first ribs 135R and the second ribs 136R are positioned with high accuracy in the entire first direction with respect to the position of the cable 110 extending in the first direction. As a result, the unevenness of the charging potential of the photosensitive drum 51 can be suppressed in the entire first direction.

Further, the gate electrode 120 is positioned between the first and second protrusions 131T and 132T and the first and second contact portions 133 and 134. In this way, the gate electrode 120 is positioned between the first and second protrusions 131T and 132T and the first and second contact portions 133 and 134, and thus, the positioning with the charging frame 130 is stabilized.

The present utility model is not limited to the above-described embodiments, and may be implemented in various modes as exemplified below.

In the above embodiment, the first protrusions 131T are arranged in three, but the first protrusions may be arranged in one or two or four or more. The second protrusions 132T may be provided in three, but may be provided in one or two or four or more.

In the above embodiment, all of the three first protrusions 131T are located closer to the first-direction center C3 of the second plate 122 than the first-direction one end C1 of the second plate 122, but is not limited to this structure. For example, at least one of the three first protrusions may be located closer to the first-direction center C3 of the second plate 122 than the first-direction one end C1 of the second plate 122.

In the above embodiment, all of the three second protrusions 132T are located closer to the first-direction center D3 of the third plate 123 than the first-direction one end D1 of the third plate 123, but is not limited to this structure. For example, at least one of the three second protrusions may be located closer to the first direction center D3 of the third plate 123 than the first direction one end D1 of the third plate 123.

In the above embodiment, the plurality of first protrusions 131T are symmetrically arranged with respect to the center C3 of the second plate 122 in the first direction, but the present utility model is not limited to this configuration, and may be asymmetrically arranged with respect to the center C3 of the second plate 122.

In the above embodiment, the plurality of second protrusions 132T are arranged symmetrically with respect to the center D3 of the third plate 123 in the first direction, but the present utility model is not limited to this configuration, and may be arranged asymmetrically with respect to the center D3 of the third plate 123.

In the above-described embodiment, the developing cartridge is capable of being mounted and dismounted with respect to the apparatus body in a state of being mounted on the drum cartridge, but the developing cartridge and the drum cartridge may be mounted to and dismounted from the apparatus body, respectively, separately.

In the above-described embodiment, the image forming apparatus 1 is a color printer, but is not limited thereto, and may be applied to a monochrome printer and other image forming apparatuses such as a copying machine or a multifunction machine.

The elements described in the above embodiments and modifications may be implemented in any combination.

Claims (8)

1. A drum cartridge, comprising:

a photosensitive drum rotatable about a drum axis extending in a first direction; and

a charger for charging the photosensitive drum, the charger including a cable extending in the first direction, a grid, and a charging frame,

the gate electrode includes:

a first plate located between the photosensitive drum and the cable, opposite to the photosensitive drum, having a plurality of gate holes;

a second plate extending from one end of the first plate in a third direction, which is perpendicular to the first direction and a second direction, to a direction away from the photosensitive drum, the second direction being a direction in which the photosensitive drum and the cable are arranged; and

a third plate extending from the other end of the first plate in the third direction in a direction away from the photosensitive drum,

the second plate has a first end connected to the first plate and a second end located on an opposite side from the first end,

the third plate has a third end connected to the first plate and a fourth end located on an opposite side from the third end,

the charging frame comprises:

a first face opposite the second end;

a first protrusion protruding from the first surface toward the photosensitive drum, in contact with the second end;

a second face opposite the fourth end; and

and a second protrusion protruding from the second surface toward the photosensitive drum and contacting the fourth end.

2. The drum cartridge according to claim 1, wherein the first projection is located closer to a center of the second plate in the first direction than one end of the second plate in the first direction, and closer to a center of the second plate in the first direction than the other end of the second plate in the first direction.

3. The drum cartridge according to claim 2, wherein the charging frame has a plurality of the first protrusions,

the plurality of first protrusions are symmetrically arranged with respect to the center of the second plate in the first direction.

4. The drum cartridge according to claim 1, wherein the second projection is located closer to a center of the third plate in the first direction than one end of the third plate in the first direction, and closer to a center of the third plate in the first direction than the other end of the third plate in the first direction.

5. The drum cartridge according to claim 4, wherein the charging frame has a plurality of the second protrusions,

the plurality of second protrusions are symmetrically arranged with respect to the center of the third plate in the first direction.

6. The drum cartridge of claim 1, wherein the charger further comprises a cleaner for cleaning the cable, slidable between one end and the other end of the cable,

the charging frame includes:

a first rail extending in the first direction and engaged with the cleaner to hold the cleaner slidably; and

a second rail extending in the first direction and engaged with the cleaner to hold the cleaner slidably, the cleaner being held between the first rail and the second rail,

the first guide rail has a first rib extending in the first direction and protruding toward the photosensitive drum,

the second guide rail has a second rib extending in the first direction and protruding toward the photosensitive drum,

at least a portion of the cable is located between the first rib and the second rib.

7. Drum cartridge according to claim 1, wherein the charging frame comprises:

a first contact portion that contacts an end portion of the grid electrode in the first direction and contacts the grid electrode from the photosensitive drum side in the second direction; and

a second contact portion that contacts the other end portion of the grid electrode in the first direction and contacts the grid electrode from the photosensitive drum side in the second direction.

8. The drum cartridge of claim 7, wherein the gate is located between the first and second protrusions and the first and second contacts.