| 摘要 |
A platen control mechanism includes a cam member which urges a cam following platen into three positions during a printing cycle. Two separate solenoids are connected to the cam member for moving the member to three distinct positions. In a first position both solenoids are de-energized thereby causing the platen to assume a wide gap position with respect to a printer head. This permits the insertion of a document. In a second condition, both solenoids are energized thereby forcing the platen into pressing relationship with a printer head. A third condition exists when one solenoid is energized and the other is de-energized thereby causing the platen to assume a narrow gap position with respect to the printer head which allows indexing motion of the document. At the end of a printing operation, both solenoids are de-energized so that the platen may return to a wide gap position permitting removal of the document. The limited movement of the platen during the mentioned document indexing minimizes the time required for a printing cycle.
|
