Photosensitive unit and image forming apparatus

A photosensitive unit configured to be mounted in a main frame of an image forming apparatus in a prescribed direction, wherein the prescribed direction is a direction in which a sheet is conveyed when an image is formed on the sheet by the image forming apparatus, and wherein the image forming apparatus includes a pressure unit, a first positioning portion, and a second positioning portion, the photosensitive unit comprising:

• a plurality of photosensitive drums juxtaposedly arrayed with each other in the prescribed direction, each photosensitive drum having an axis extending in an axial direction;
• a pair of metal plates spaced away from each other in the axial direction and supporting the plurality of photosensitive drums, the pair of metal plates being configured to be positioned on the second positioning portion;
• and
• a resin frame supporting the pair of metal plates and configured to support a plurality of developer cartridges, the resin frame being configured to be positioned on the first positioning portion,
• wherein the pair of metal plates is pressed against the second positioning portion to be positioned with respect to the main frame when the resin frame is pressed by the pressure unit in the prescribed direction,
• wherein the resin frame comprises a first protrusion protruding toward a side at which the pair of metal plates is positioned, and a supported portion provided on an upstream end portion of the resin frame in the prescribed direction and configured to be pressed by the pressure unit, the supported portion configured to be supported by the first positioning portion to position the resin frame with respect to the main frame in a vertical direction, and
• wherein each of the pair of metal plates comprises a first engagement portion and a second engagement portion, the first engagement portion including a downstream section in the prescribed direction that is configured to engage with the first protrusion to be pressed by the first protrusion, the second engagement portion being formed at a downstream end portion of each of the metal plates in the prescribed direction, the second engagement portion being configured to be engaged with the second positioning portion such that the pair of metal plates is restricted from moving in the prescribed direction and the vertical direction.

An image forming apparatus comprising:

• a main frame;
• a photosensitive unit configured to be mounted in the main casing in a prescribed direction, wherein the prescribed direction is a direction in which a sheet is conveyed when an image is formed on the sheet by the image forming apparatus;
• a first positioning portion and a second positioning portion disposed in the main frame, both ends of the photosensitive unit in the prescribed direction being positioned on the first positioning portion and the second positioning portion, respectively;
• a pressure unit configured to press the photosensitive unit in the prescribed direction;
• wherein the photosensitive unit comprises:
• a plurality of photosensitive drums juxtaposedly arrayed with each other in the prescribed direction, each photosensitive drum having an axis extending in an axial direction;
• a pair of metal plates spaced away from each other in the axial direction and supporting each photosensitive drum;
• and
• a resin frame supporting the pair of metal plates and configured to support a plurality of developer cartridges each supplying developer to each photosensitive drum,
• wherein the pair of metal plates is pressed against the second positioning portion to be positioned with respect to the main frame when the resin frame is pressed by the pressure unit in the prescribed direction,
• wherein the resin frame comprises a first protrusion protruding toward a side at which the pair of metal plates is positioned, a pressed portion configured to be pressed by the pressure unit, and a supported portion provided on an upstream end portion of the resin frame in the prescribed direction, the supported portion configured to be supported by the first positioning portion to position the resin frame with respect to the main frame in a vertical direction, and
• wherein each of the pair of metal plates comprises a first engagement portion and a second engagement portion, the first engagement portion including a downstream section in the prescribed direction that is configured to engage with the first protrusion to be pressed by the first protrusion, the second engagement portion being formed at a downstream end portion of the pair of metal plates in the prescribed direction, the second engagement portion being configured to be engaged with the second positioning portion such that the pair of metal plates is restricted from moving in the prescribed direction and the vertical direction.

An image forming apparatus comprising:

• a main frame;
• a photosensitive unit configured to be mounted in the main casing in a prescribed direction;
• a first positioning portion and a second positioning portion disposed in the main frame, both ends of the photosensitive unit in the prescribed direction being positioned on the first positioning portion and the second positioning portion, respectively;
• a pressure unit configured to press the photosensitive unit in the prescribed direction;
• wherein the photosensitive unit comprises:
• a plurality of photosensitive drums juxtaposedly arrayed with each other in the prescribed direction, each photosensitive drum having an axis extending in an axial direction;
• a pair of metal plates spaced away from each other in the axial direction and supporting each photosensitive drum;
• and
• a resin frame supporting the pair of metal plates and configured to support a plurality of developer cartridges each supplying developer to each photosensitive drum,
• wherein the pair of metal plates is pressed against the second positioning portion to be positioned with respect to the main frame when the resin frame is pressed by the pressure unit in the prescribed direction,
• wherein the resin frame comprises a first protrusion protruding toward a side at which the pair of metal plates is positioned, and a supported portion provided on an upstream end portion of the resin frame in the prescribed direction and configured to be pressed by the pressure unit, the supported portion configured to be supported by the first positioning portion to position the resin frame with respect to the main frame in a vertical direction,
• wherein each of the pair of metal plates comprises a first engagement portion and a second engagement portion, the first engagement portion including a downstream section in the prescribed direction that is configured to engage with the first protrusion to be pressed by the first protrusion, the second engagement portion being formed at a downstream end portion of each of the pair of metal plates in the prescribed direction, the second engagement portion being configured to be engaged with the second positioning portion such that the pair of metal plates is restricted from moving in the prescribed direction and the vertical direction.