| 摘要 |
<p>In a vacuum printer for the graphic arts having a bed, a blanket frame upon the bed including a flexible impervious blanket having a peripheral sealing bead, a glass frame juxtaposed over the blanket frame in snug registry with the blanket bead defining a contact printing chamber, the glass frame being movably mounted for opening and closing movements relative to the blanket frame, a vacuum source having a first vacuum conduit extending into communication with the printing chamber for evacuating it; the improvement which comprises a perforated blanket support plate within the blanket frame underlying the blanket and defining within the blanket frame a blanket chamber. A second vacuum conduit interconnects the vacuum source and the blanket chamber. An electronic control is connected to the conduits for evacuating the blanket chamber, and after a pre-set period evacuating the printing chamber. In the method of contact printing wherein the step of communicating vacuum to a vacuum printing chamber between a glass frame and a flexible blanket is preceded by the step of communicating vacuum to a blanket chamber below the blanket for a predetermined interval holding the blanket away from the glass frame until the vacuum printing chamber is fully evacuated.</p> |
