Printing system exposure module optic structure and method of operation

Claim 1

A printing element spatial light modulation device for use in an exposure unit of a printing system, said exposure unit including a source of light separately positioned with respect to said spatial light modulation device such that unmodulated light from said source falls upon said device and a focusing apparatus for accepting light selectively reflected from certain pixels of said device, said device comprising a plurality of pixel elements formed in a substrate, each said pixel being electrostatically deflectable; addressing circuitry also formed in said substrate, said addressing circuity operable upon receipt of a data signal addressed to a particular pixel for enabling said deflection of said addressed pixel such that light which otherwise would be reflected by said pixel away from said focusing apparatus is instead reflected to said focusing apparatus; and mounting supports for removably attaching said printing element to said exposure unit.

Claim 10

The method of establishing an exposure unit for a xerographic printing system where images are created on a photoconductive surface for transfer to a printed surface, said method comprising the steps of: establishing a source of light rays at a first location within said unit; positioning a substrate at a second location within said unit, said substrate containing at least one row of spaced apart individually selectable and rotatable mirrors; directing said light rays onto a desired active area of said substrate by positioning lens elements constrained by said exposure unit to collect, direct, and suitably aperture light rays from said source onto said substrate to form an image of said source rays magnified so as to fall at, and substantially fill, the aperture of a subsequent imager lens; constructing a light ray baffle between said first and second location, said baffle being a series of saw-tooth steps with walls of said steps perpendicular to the optic path of light rays reflected by said mirrors; mounting a reflected light ray imaging lens in conjunction with said baffle such that said light rays controllably reflected from said mirrors to said imaging lens will be focused via said lens onto said surface; and adjusting said substrate so that light rays from said source which impinge on said substrate are reflected away from said imaging lens by said wells of said light gathering baffle when said mirrors have not been selected for rotation and such that upon the selective rotation of any mirror light rays from that selected mirror will pass through said baffle without impacting said baffle walls and thence into an aperture of said imaging lens.

Claim 13

The method of operating an exposure unit containing a printing element spatial light modulation device, said exposure unit including a source of light separately positioned with respect to said spatial light modulation device such that unmodulated light from said source falls upon individual pieces of said device and a focusing apparatus for accepting light selectively reflected from certain pixels of said device, and wherein when the velocity of said drum rotations fluctuate, banding of the final printing image occurs and wherein said pixels of said substrate include at least two rows of selectively rotatable mirrors, said method comprising the steps of: electrostatically deflecting a plurality of pixel elements formed in a substrate, said deflecting controlled by addressing circuitry also formed in said substrate; processing via said addressing circuitry data signals addressed to particular pixels so as to enable said deflection of said addressed pixels such that light which otherwise would be reflected by said addressed pixels away from said focusing apparatus is instead reflected to said focusing apparatus; and coordinating the selective timing of said rotation of mirrors in alternate pixels rows to coincide with variations in rotation and velocity of said drum so as to reduce said banding.

Claim 15

A system for modulating energy, said system comprising: an energy modulating device; a source of energy arrayed at an angle to said energy modulating device, and directed onto said device by intervening optical lens elements; said device operable for modulating said energy to provide an array of independent energy modulated spots, and said device comprising a set of deflectable elements which can be displaced into at least two orientations with respect to said energy source, each said element independently operable for focusing a reflected image of said energy source along a common first axis under control of a modulating signal and for focusing said reflected image along a common second axis when said modulating signal is not present, said images separated by a dead-band; and an energy baffle at least partially surrounding and disposed along both said axes, said baffle arranged to pass said first axis reflected images while attenuating said second axis reflected images.

Claim 22

A system for modulating energy, said system comprising: a source of energy directed on a modulating device by intervening optical lens elements; said modulating device including a set of deflectable pixel elements which can be displaced into at least two orientations with respect to said energy source, each said element independently operable for focusing a reflected image of said energy source along a common first axis under control of a modulating signal and for focusing said reflected image along a common second axis when said modulating signal is not present, said images separated by a dead-band; and said system further comprising: an imaging lens displaced from said set of pixel elements and arranged along said first axis.

Claim 28

A system for modulating energy, said system comprising: a source of energy arrayed at an angle to an energy modulating device, and directed on said device by intervening optical lens elements; a source of signals operable for modulating said energy to provide an array of independently energy modulated spots or pixels; a device comprising a set of deflectable pixels which can be displaced into at least two orientations with respect to said energy source, each said pixel independently rotatable for focusing a reflected image of said energy source along a common first axis under control of a modulating signal and for focusing said reflected image along a common second axis when said modulating signal is not present, said images separated by a dead-band, said set of deflectable pixels arranged to rotate about an axis in the plane of said device, said axis being orthogonal to said common first axis; said set of deflectable pixels having at least two positions of deflection corresponding to the modulated or unmodulated state; said modulated direction of rotation being disposed so as to modulate an energy image of said source from a focus plane of said common axis to a locus of image plane of said common first axis, concentrated on said imager lens.