DYNAMIC ADJUSTABLE FOCUS FOR LED WRITING BARS USING PIEZOELECTRIC STACKS

摘要

According to aspects of the embodiments, there is provided methods of dynamically focusing an LED print bar or printhead using piezoelectric stacks. The stack is mounted on either end of the LED bar to adjust the focus of the bar against the photoreceptor surface. The piezo level could be either controlled through active feedback of some description such as optical or electrical, or as a service or manufacturing input. With electronic control, focus adjustments can be made by the machine, and dynamically, if needed. In one embodiment, a flextensional cell structure is employed to amplify the movement of the piezo stack to move the LED bar in the order of >50 microns closer or away from the photoreceptor surface.

主权项

1. A printing system comprising:
a light source having a plurality of light emitting elements for emitting a plurality of light beams to a photoreceptor medium, wherein the light source is located at a distance (D) from the photoreceptor medium in such a manner that each light beam strikes the photoreceptor medium at a spot to form an image; and a piezo actuating system to produce fine adjustments to the distance between the light source and the photoreceptor medium by moving the light source towards or away from the photoreceptor medium, the piezo actuating system including a piezo driver and at least one piezo stack; wherein the at least one piezo stack enables bidirectional motion of the light source as the at least one piezo stack expands and contracts under a changing applied actuation signal.