Electrical drive for scanning optics in a continuously variable reduction copier

A substantially continuously variable reduction ratio document copier machine with scanning carriage means driven in servo relationship to image carrier means including:

• a motor,
• image carrier means driven by said motor for recording an image thereon,
• scanning carriage means for scanning a document to be copied,
• servo motor means for driving said scanning carriage means for scanning movement in synchronism with the motion of said image carrier means,
• said servo motor means including a control means for driving said scanning carriage means at a unique velocity relative to the motion of said image carrier means during a scanning movement,
• wherein said control means includes:
• first transducing means providing a pulse output with frequency representative of image carrier means velocity,
• second transducing means providing a pulse output with frequency representative of scanning carriage means velocity,
• means for differencing a constant times said first transducing means output and said second transducing means output and providing an output representative of said difference,
• said means for differencing including:
• dividing means clocked by said pulse output of said first transducing means for dividing by a constant selected in dependence on said selected reduction ratio, and
• a phase comparator responsive to said pulse output of said second transducing means and said dividing means,
• and means for adjusting scanning carriage means velocity to reduce said output representative of said difference.

A document copier capable of substantially continuous variable reduction ratio with scanning carriage means driven in servo relationship to image carrier means including:

• a motor,
• image carrier means driven by said motor for recording an image thereon,
• scanning carriage means for scanning a document to be copied,
• servo motor means for driving said scanning carriage means for scanning movement in synchronism with the motion of said image carrier means,
• said servo motor means including,
• a servo motor, and
• energization means to energize said servo motor with energization selected in dependence on image carrier position.

A document copier capable of substantially continuously variable reduction ratio operation with scanning carriage means driven in servo relationship to image carrier means including:

• a motor,
• image carrier means driven by said motor for recording an image thereon,
• scanning carriage means for scanning a document to be copied,
• servo motor means for driving said scanning carriage means for scanning movement in synchronism with the motion of said image carrier means,
• wherein said servo motor means includes:
• velocity control means for maintaining velocity of a scanning carriage in said scanning carriage means relative to image carrier means velocity, a ratio of said velocities selected in accordance with said reduction ratio,
• acceleration control means for accelerating said scanning carriage for a predetermined time, said predetermined time selected in accordance with a selected reduction ratio,
• means responsive to image carrier position for enabling said acceleration control means, and
• timing means for disabling said acceleration control means and for enabling said velocity control means after a predetermined acceleration time, predetermined in accordance with said selected reduction ratio.

A document copier capable of substantially continuously variable reduction ratio with scanning carriage means driven in servo relationship to image carrier means including:

• a motor,
• image carrier means driven by said motor for recording an image thereon,
• scanning carriage means for scanning a document to be copied,
• servo motor means for driving said scanning carriage means for scanning movement in synchronism with the motion of said image carrier means,
• wherein said servo motor means includes:
• deceleration means for decelerating said servo motor means when enabled,
• means responsive to position of a scanning carriage in said scanning carriage means for disabling said deceleration means, and
• position error means enabled on disablement of said deceleration means for driving said servo motor means in accordance with scanning carriage position error.

A document copier machine with scanning carriage means driven in servo relationship to image carrier means including:

• a motor,
• image carrier means driven by said motor for recording an image thereon,
• scanning carriage means for scanning a document to be copied,
• servo motor means for driving said scanning carriage means for scanning a movement in synchronism with the motion of said image carrier means, said servo motor means including a first closed loop control means to accelerate said scanning carriage means from a rest condition towards a desired speed before reaching a start of image transfer position, and second closed loop control means for maintaining said scanning carriage means at a constant speed, relative to said image carrier means, throughout said scanning, said first closed loop control means for decelerating said scanning carriage means and third closed loop control means for moving said scanning carriage means to a reference position.