Image forming apparatus, image forming system, and external unit

An image forming system comprising:

• an image forming apparatus configured to form an image on a recording material;
• and
• an external unit connected to the image forming apparatus,
• wherein the image forming apparatus includes
• a first casing including a first outer wall portion configured to form at least a part of a facing surface facing the external unit, and a second outer wall portion configured to form at least a first part of an exterior surface intersecting with the facing surface, the external unit being provided at a position between the first exterior surface and an installation surface where the image forming system is installed, and
• a body side connector provided inside of the first casing,
• wherein the external unit includes
• a second casing including a unit side outer wall portion configured to form a second part of the exterior surface, the second part being different from the first part, and
• a unit side connector electrically connected with the body side connector,
• wherein an external-unit-side edge of the second outer wall portion includes a concave portion where the edge of the second outer wall portion is recessed toward the image forming apparatus from the external unit,
• wherein an image-forming-apparatus-side edge of the unit side outer wall portion includes a projection portion where the edge of the unit side outer wall portion projects toward the image forming apparatus from the external unit, the projection portion engaging with the concave portion, and
• wherein, when viewed in a direction perpendicular to the second outer wall portion, the projection portion overlaps at least partially with the body side connector.

An image forming system comprising:

• an image forming apparatus configured to form an image on a recording material;
• and
• an external unit connected to the image forming apparatus,
• wherein the image forming apparatus includes
• a first casing that includes a first outer wall portion configured to form at least a part of a first exterior surface facing the external unit, and a second outer wall portion configured to form at least a first part of a second exterior surface intersecting with the first exterior surface, the external unit being provided at a position between the first exterior surface and an installation surface where the image forming system is installed,
• a body side connector provided inside of the first casing, and
• a cover member configured detachably attached to the first casing,
• wherein the first outer wall portion includes a first opening configured to expose a connection terminal of the body side connector,
• wherein the second outer wall portion includes a second opening configured to expose a component provided inside of the first casing,
• wherein the cover member includes a first cover portion configured to cover the first opening in a state where the cover member is attached to the first casing, and a second cover portion formed integrally with the first cover portion and configured to cover the second opening in the state where the cover member is attached to the first casing,
• wherein the external unit includes
• a second casing including a unit side outer wall portion configured to form a second part of the second exterior surface, the second part being different from the first part, and
• a unit side connector electrically connected with the body side connector,
• wherein the first cover portion includes a fixed portion fixed to the second cover portion, a moving portion configured to slide with respect to the fixed portion, and an urging member configured to urge the moving portion with respect to the second cover portion in an attachment direction intersecting with the second outer wall portion, and
• wherein, in a case where the cover member is attached to the first casing, the moving portion is configured to open the first opening while resisting an urging force of the urging member.

An external unit configured to be connected on an outer wall portion of a casing included in an image forming apparatus which forms an image on a recording material, the external unit comprising:

• a unit side casing including a unit side outer wall portion configured to form at least a part of an exterior surface intersecting with a facing surface to face the outer wall portion of the casing of the image forming apparatus;
• and
• a unit side connector projecting toward a side of the image forming apparatus further than the facing surface and configured to be electrically connected with the image forming apparatus,
• wherein the unit side outer wall portion includes a protruding portion formed by a part of an image-forming-apparatus-side edge of the unit side outer wall portion projecting toward the image forming apparatus from other part of the image-forming-apparatus-side edge, and
• wherein the protruding portion overlaps with the unit side connector when viewed from an outside of the unit side outer wall portion in a direction perpendicular to a projecting direction of the unit side connector.