Apparatus and method for maintaining a substantially constant closely spaced working distance between an inkjet printhead and a printing receiver

摘要

The present invention resides in an apparatus (8) and method for maintaining a print head (10) at a substantially constant, closely spaced working distance (22) from a surface (17) of a printing receiver (16) during relative translational movement between the print head (10) and the receiver (16) along a predetermined path of movement for depositing liquid or ink droplets (12) onto the surface (17), the apparatus (8) including an actuator (20) connected to the print head (10) and controllably actuable for moving the print head (10) toward and away from the receiver (16), an element (35,36) for detecting a representative distance between the print head (10) and locations on the surface (17) of the receiver (16) along the path of movement and generating a signal having a value representative of or related to the representative distance, an element (46) for comparing the signal value to a reference value representative of the working distance (22) for determining a difference between the signal value and the reference value and generating a control signal representative of the difference, and a control element (24) for receiving the control signal and responsively controllably actuating the actuator (20) to move the print head (10) toward or away from the receiver (16). <IMAGE>