System for controlling the reciprocation of a scanning apparatus

A system for controlling the reciprocation of a scanning apparatus comprising:

• scanning means for scanning an original, said scanning means adapted to scan from a home position across said original to a scanned position and returning it from the scanned position back to the home position;
• a D.C. motor for driving said scanning means;
• a switching circuit for providing electric power to said D.C. motor;
• home position detecting means for detecting when said scanning means is in said home position;
• intermediate position detecting means for detecting when said scanning means moves past a predetermined intermediate position;
• measure means for measuring a distance of movement of said scanning means;
• speed detecting means for detecting the speed of said scanning means;
• control means adapted to said switching circuit for controlling the movement of the scanning means such that:
• said scanning means scans across said original at a predetermined constant speed;
• when said scanning means reaches said scanned position, it starts to return back towards said home position with application of a constant supply of power having a predetermined level;
• when said scanning means is returned back to said predetermined intermediate position as detected by said intermediate position detecting means, said masure means starts to measure a distance of movement of said scanning means;
• when said measure means measures a preselected distance TM said scanning means is braked until the returning speed is reduced to a predetermined low speed as detected by said speed detecting means;
• said scanning means is returned at said low constant speed until said home position detecting means detects that said scanning means is in said home position;
• said measure means measures the distance CT of movement of said scanning means moved at said low constant speed;
• said scanning means is stopped at said home position;
• and said distance CT is used for calculating a distance TM for the next cycle of scan so that the distance CT in the next cycle of scan is controlled to be substantially equal to a predetermined distance.

A system for controlling the reciprocation of a scanning apparatus for a copying machine comprising:

• scanning means for scanning an original document, said scanning means adapted to scan from a home position across said original document to a scanned position and back to said home position at a variable speed;
• drive means for driving said scanning means;
• intermediate detecting means for detecting when said scanning means is at a position intermediate said home position and said scanned position;
• braking means for providing braking action to said scanning means;
• measurement means for measuring movement of said scanning means;
• data storage means responsive to said measurement means for storing data which corresponds to measured movement of said scanning means from said scanned position back to said home position;
• control means connected to the data storage means and responsive to said intermediate detecting means for controlling said braking means such that braking action is applied to said scanning means during a high speed return cycle subsequent to the passage of said scanning means past said intermediate position towards said home position, said control means is also responsive to said measurement means measurement of the subsequent constant speed movement of the scanning means after the braking means has reduced the hih speed return movement to a low constant speed, to provide subsequent adjustment to the time of applying a braking action in a subsequent return movement whereby the low speed movement is maintained over a substantially constant predetermined distance to minimize the return time in a copying cycle.