Developing cartridge capable of facilitating toner circulation at developing roller support portion

摘要

A developing cartridge includes: a first frame; and a second frame melt-bonded to the first frame. The first frame includes: a first melt-bonding surface; and a second melt-bonding surface closer to a developing roller than the first melt-bonding surface. The second frame includes: a third melt-bonding surface; a fourth melt-bonding surface; and a center surface facing the first frame. The center surface is closer to an axial center region of the developing roller than the fourth melt-bonding surface in the axial direction. The center surface has a first center surface and a second center surface closer to the developing roller than the first center surface in the first direction. The second center surface forms an obtuse angle with the first center surface and is separated from the first frame farther than the fourth melt-bonding surface in a direction perpendicular to the fourth melt-bonding surface.

主权项

1. A developing cartridge comprising:
a developing roller having an axis extending in an axial direction and an axial center region in the axial direction; a first frame including a toner accommodating portion and a developing roller support portion, the toner accommodating portion having an edge portion extending in a first direction perpendicular to the axial direction, the developing roller support portion supporting the developing roller and being in communication with the toner accommodating portion, the first frame comprising:
a first melt-bonding surface extending along the edge portion of the toner accommodating portion; anda second melt-bonding surface positioned closer to the developing roller than the first melt-bonding surface to the developing roller, the second melt-bonding surface forming a first obtuse angle with the first melt-bonding surface; and a second frame covering the toner accommodating portion and the developing roller support portion, the second frame being melt-bonded to the first frame, the second frame comprising:
a third melt-bonding surface facing the first melt-bonding surface and melt-bonded to the first melt-bonding surface;a fourth melt-bonding surface facing the second melt-bonding surface and melt-bonded to the second melt-bonding surface; and a center surface facing the first frame and extending in the axial direction, the center surface being positioned closer to the axial center region of the developing roller than the fourth melt-bonding surface to the axial center region of the developing roller with respect to the axial direction, the center surface having a first center surface extending in the first direction and a second center surface positioned closer to the developing roller than the first center surface to the developing roller with respect to the first direction, the second center surface forming a second obtuse angle with the first center surface, the second center surface being separated from the first frame farther than the fourth melt-bonding surface from the first frame with respect to a direction perpendicular to the fourth melt-bonding surface, wherein the second obtuse angle formed between the first center surface and the second center surface is equal to or greater than 120° and smaller than 180°.