Electrophotographic apparatus and sheet guide mechanism

A sheet guide mechanism comprising:

• a guide path along which a sheet-like member is guided, said guide path having upper and lower guide surfaces and including at least one enclosed gap for receiving a sheet, said enclosed gap being formed along said guide path, and having upper and lower walls respectively defined by said upper and lower guide surfaces, and opposed sides comprising projections positioned between said upper and lower guide surfaces, said projections being attached to one of said upper and lower guide surfaces, said projections contacting the other of said upper and lower guide surfaces to form said enclosed gap, said projections formed on said lower guide surfaces;
• a lower stationary guide having an upper surface which defines said lower guide surface, wherein said projections are formed on said upper surface of said lower stationary guide, said projections extending upwardly from said upper surface by a predetermined distance;
• a lower roller rotatably attached to said lower stationary guide;
• a shiftable member, positioned above said lower stationary guide member, said shiftable member being shiftable between a guide position located adjacent said upper surface of said lower stationary guide, and a remote position;
• an upper movable guide, connected to a lower surface of said shiftable member, said movable guide having a lower surface which defines said upper guide surface when such shiftable member contacts said projections;
• and
• a first elastic member provided between said shiftable member and said upper movable guide, for elastically contacting said protrusions with said upper movable guide when said shiftable member is located in said guide position, said protrusions being spaced by a predetermined distance sufficient to permit a sheet of predetermined width to be fed along said guide path, so that contact between said projections and said upper movable guide does not obstruct passage of said sheet;
• said upper movable guide comprises a leaf spring having a lower surface, said lower surface of said leaf spring defining said upper guide surface when said shiftable member contacts said projections in said guide position;
• said projections contact said upper movable guide when said shiftable member is located in said guide position, so as to define said enclosed gap, said enclosed gap being sized to allow a single sheet to pass therethrough.

A sheet guide mechanism comprising:

• upper and lower guide surfaces which oppose each other to form a guide path along which a sheet is guided;
• and
• means, extending from one of said upper and lower guide surfaces towards the other of said upper and lower guide surfaces, and being spaced from each other along a plane located between said guide surfaces, for spacing the guide surfaces from each other to form a predetermined gap for guiding the sheet;
• a lower stationary guide member having an upper surface which defines said lower guide surface, wherein said spacing means are located on said upper surface of said lower stationary guide member, said spacing means protruding upwardly from said upper surface of said lower stationary guide member by a predetermined distance;
• a lower register roller rotatably attached to said lower stationary guide member, said lower register roller having two ends and a shaft portion at each end;
• a shiftable member arranged above said lower stationary guide member, said shiftable member being shiftable between a guide position adjacent to said upper surface of said lower stationary guide member, and a remote position remote from said upper surface of said lower stationary guide member;
• an upper stationary guide member fixedly attached to an under surface of said shiftable member and being stationary with respect to said shiftable member, said upper stationary guide member having a lower surface which defines one part of said upper guide surface when said shiftable member is located in said guide position;
• and
• an upper movable guide member at ached to said under surface of said shiftable member in a shiftable manner, said upper movable guide member having a lower surface which defines another part of said upper guide surface when said shiftable member contacts said spacing means in said guide position, said spacing means being spaced apart, along the plane located between said upper and lower guide surfaces, by a distance which is greater than a width of a predetermined sheet which is fed along said guide path, so that contact between said spacing means and said upper movable guide member does not obstruct passage of the sheet along said path;
• wherein said upper stationary guide member, said upper movable guide member and an upper register roller are successively arranged in the feeding direction of the sheet, said spacing means contacting said upper movable guide member when said shiftable member is located in said guide position to form said predetermined gap, said predetermined gap being sized to allow a single sheet to pass therethrough.

A mechanism for conducting a sheet through an electrophotographic apparatus along a predetermined path, said apparatus including at least one pair of rollers and an image transfer area, said rollers being located upstream of said image transfer area along said path, said apparatus comprising:

• means for feeding said sheet towards said rollers during a first predetermined time period, and for stopping said sheet at the end of said time period;
• means for further feeding said sheet towards said rollers for a second predetermined time period, into a position in which said sheet contacts at least one of said rollers, in order to align said sheet with respect to said rollers;
• and
• means for prohibiting movement of said rollers during said second predetermined time period.

An electrophotographic apparatus comprising:

• a sheet guide path along which a sheet is movably guided;
• an imager, positioned along the sheet guide path, for forming an image on the sheet;
• a first drive assembly for driving the sheet, along a first portion of said path, towards a second drive assembly for moving said sheet along said path;
• and
• a controller for controlling said first drive assembly so as to drive the sheet into contact with said second drive assembly without substantially skewing the position of said sheet within said apparatus, wherein said controller controls said first drive assembly to drive said sheet during at least two distinct time periods and controls said second drive assembly to be stopped during at least a second of said at least two distinct time periods.

A method for feeding a sheet in an electrophotographic apparatus having a plurality of adjacent rollers, said method comprising:

• feeding the sheet towards the rollers during a first predetermined time period, and stopping the sheet thereafter;
• thereafter, feeding the sheet for a second predetermined period of time, into a position in which the sheet contacts at least one of the rollers, in order to ensure alignment and substantially prevent skewing of the sheet within the electrophotographic apparatus;
• and
• prohibiting movement of the rollers during the second predetermined time period.