Reset data creation mechanism for photoconductive drum counter

A detection mechanism for detecting an installation of a detachable member to a main body, which comprises:

• a movable member provided on said detachable member and being movable back and forth between a first position and a second position, said movable member being set in said first position prior to a first installing operation of said detachable member on the main body;
• detecting means, provided on the main body, for detecting said movable member in said first position but being incapable of detecting said movable member in said second position;
• actuating means, provided on the main body, for causing said movable member to move from said first position to said second position upon installation of said detachable member into the main body;
• and
• lock means for locking said movable member to said second position after said actuating means actuates said movable member to said second position,
• whereby said detecting means detects only a first installation of said detachable member and establishes a signal as a direct result of the detection of said first installation.

A reset data creation mechanism for a photoconductor drum counter used in an imaging apparatus for creating reset data in response to which the counter is reset,

• wherein said imaging apparatus is provided with a main body, and a photoconductive drum unit which includes the photoconductive drum and a holding member for holding said drum and which is detachably mounted to the main body, and
• said counter counts data output in synchronism with the operation of the photoconductive drum, said reset data creation mechanism comprising:
• switch means, provided on said main body, for outputting a signal, said counter being reset in response to a change of the level of said signal;
• a resettable switching member, movably provided on said holding member, for changing the level of said signal output from said switch means when said drum unit is initially mounted to a predetermined position ins aid main body;
• actuating means for actuating said switching member to be out of a region where the level of said signal output from said switching means is changed for mountings of said drum unit subsequent to said initial mounting;
• and
• means for holding said switching member out of said region after said actuating means has once actuated;
• wherein said switch means outputs a change of the level of said signal in direct response to said initial mounting of said drum unit.