1. Field of the Invention
The present invention generally relates to a system for controlling movement of a document table in a copying apparatus of the type in which the document table is movably disposed thereon, and more particularly, to the improvement of control at the beginning of copying operation.
2. Description of the Prior Art
Recently, a portable electrophotographic copying apparatus came to be known. The portable copying apparatus is generally formed with a moving document table so that any space may be effectively utilized. Accordingly, such an apparatus is provided with a lock mechanism for locking the document table to prevent damage thereto when being carried. The Japanese Patent Laid-Open Application No. 61-65228 discloses one of the portable copying apparatuses.
FIG. 1 is a schematic view of a moving document table type copying apparatus having a lock mechanism. This apparatus is provided with a document table 1 on its upper surface and a photosensitive member 2 in the form of a drum substantially at a central portion within its housing. The document table 1 is movable in the direction shown by arrows F and R. The apparatus accommodates a developing device 3 on the right side of the photosensitive member 2 and a cleaning device 4 on the left side thereof, as viewed in FIG. 1. The apparatus is further provided with a handle 5 on its right side and a hooked lock member 6 on its left side, as viewed in FIG. 1.
When the document table 1 is locked, it is necessary to initially lift up the lock member 6 against the biasing force of a compression spring while manually slightly moving the document table 1 in the direction of the arrow F. Thereafter, the document table 1 is securely locked by engaging it with the lock member 6 while moving it in the direction of the arrow R. Under such conditions, the document table 1 would never slip off the apparatus housing even when the apparatus is lifted up.
When the lock of the document table 1 is released, the document table 1 is manually slightly moved in the direction of the arrow F. In this event, engagement between the document table 1 and the lock member 6 is released and the lock member 6 is drawn into the apparatus housing by virtue of the biasing force of the spring.
On the other hand, when a document placed on the document table 1 is copied, it is scanned from its right end. Because of this, the document table 1 initially moves in the direction of the arrow R until its right end reaches a start position at which the right end is located above a bundled optical fiber 7. However, if an operator starts the copying operation without unlocking the document table 1 after the transportation of the apparatus, movement of the document table 1 in the direction of the arrow R exerts excessive force upon the lock member 6, occasionally damaging the lock member 6, the document table 1 or its drive system.