Single-pass imaging system with anamorphic optical system
View Patent ↗An single-pass imaging system utilizes a light source, a spatial light modulator and an anamorphic optical system to form a substantially one-dimensional high intensity line image on an imaging surface (e.g., the surface of a drum cylinder). The light source and the spatial light modulator are used to generate a relatively low intensity two-dimensional modulated light field in accordance with an image data line such that each pixel image of the line is elongated in the process (Y-axis) direction. The anamorphic optical system utilizes a cylindrical/acylindrical optical element to anamorphically image and concentrate the modulated light field in the process direction to form the substantially one-dimensional high intensity line image. The line image is generated with sufficient energy to evaporate fountain solution from the imaging surface. The imaging system simultaneously generates all component pixel images of the line image, thus facilitating a printing apparatus capable of 1200 dpi or greater.
1. A single-pass imaging system for generating a substantially one-dimensional line image on an imaging surface in accordance with an image data file, the system comprising:
means for generating a two-dimensional modulated light field in accordance with the image data file, wherein said means comprises:
a homogenous light generator including at least one light source for generating one or more light beams, and at least one light homogenizer including means for homogenizing said one or more light beams such that portions of said homogenized light beams form a homogeneous light field, and
a spatial light modulator including a plurality of light modulating elements disposed in an array, and means for individually configuring the plurality of light modulating elements into one of two modulated states in accordance with the image data file such that the two-dimensional light field is generated only by portions of the homogeneous light field directed from first light modulating elements of said array in a first modulated state; and
an optical system including two or more cylindrical/acylindrical optical elements that are operably positioned and arranged to image and concentrate the two-dimensional modulated light field such that said imaged and concentrated modulated light field forms said substantially one-dimensional line image in a cross-process direction on said imaging surface, the optical system including:
a cross-process optical subsystem including at least one cross-process cylindrical/acylindrical optical element arranged to image said two-dimensional modulated light field in a cross-process direction on the imaging surface, the cross-process direction being perpendicular to the process direction; and
a process-direction optical subsystem including at least one process-direction cylindrical/acylindrical optical element arranged to focus said two-dimensional modulated light field in the process direction on the imaging surface,
wherein the two-dimensional light field has a first width in the cross-process direction and a first height in the process direction, and
wherein the process-direction optical subsystem comprises at least one cylindrical/acylindrical optical element that is shaped and positioned to concentrate the two-dimensional modulated light field in the process direction onto the imaging surface such said substantially one-dimensional line image has a second width in the cross-process direction that is equal to or greater than the first width of the two-dimensional modulated light field.
2. The imaging system according to claim 1 , wherein the optical system comprises at least one cylindrical/acylindrical lens that images the two-dimensional modulated light field onto the image surface in the cross-process direction and has at least one elongated curved refractive surface that is shaped and positioned to concentrate the two-dimensional modulated light field onto the imaging surface in the process direction.
3. The imaging system according to claim 2 , wherein the cross-process optical subsystem comprises one or more cylindrical/acylindrical lens elements that are shaped and arranged to cooperatively concentrate the two-dimensional modulated light field in the cross-process direction, and wherein the process-direction optical subsystem comprises only one cylindrical/acylindrical lens element that is shaped and positioned to concentrate the two-dimensional modulated light field in the process direction onto the imaging surface.
4. The imaging system according to claim 2 , wherein the process-direction optical subsystem comprises two or more lens elements that are respectively shaped and positioned to cooperatively concentrate the two-dimensional modulated light field in the process direction onto the imaging surface.
5. The imaging system according to claim 1 , wherein the process-direction optical subsystem comprises at least one cylindrical/acylindrical mirror element that is shaped and positioned to concentrate the two-dimensional modulated light field in the process direction onto the imaging surface.
6. The imaging system according to claim 5 , wherein the process-direction optical subsystem further comprises a flat fold mirror that is positioned to reflect the two-dimensional modulated light onto the at least one cylindrical/acylindrical mirror element.
7. The imaging system according to claim 5 , wherein the process-direction optical subsystem comprises at least two cylindrical/acylindrical mirror elements that are respectively shaped and positioned to cooperatively concentrate the two-dimensional modulated light field in the process direction onto the imaging surface.
8. The imaging system according to claim 1 , wherein the cross-process optical subsystem comprises first and second focusing lenses that are shaped and positioned to image the two-dimensional modulated light field in the cross-process direction onto the imaging surface.
9. The imaging system according to claim 8 , wherein the cross-process optical subsystem which further comprises a third focusing lenses comprises three focusing lenses that are shaped and positioned to image the two-dimensional modulated light field in the cross-process direction onto the imaging surface.
10. The imaging system according to claim 8 , wherein the optical system further comprises:
a field lens disposed between the cross-process optical subsystem and said means for generating said two-dimensional modulated light field; and
an aperture stop disposed between first and second focusing lenses of the cross-process optical subsystem.
11. The imaging system according to claim 10 , wherein the process-direction optical subsystem comprises at least one focusing mirror that is shaped and positioned to concentrate the two-dimensional modulated light field in the process direction onto the imaging surface.
12. The imaging system according to claim 1 ,
wherein the plurality of light modulating elements are arranged in a plurality of rows and a plurality of columns, wherein each said column includes an associated group of said plurality of light modulating elements, and
wherein the optical system is arranged to concentrate modulated light portions received from each associated group of said plurality of light modulating elements of each said column onto an associated line image portion of said elongated line image.
13. The imaging system according to claim 12 ,
wherein each of the plurality of light modulating elements comprises a microelectromechanical (MEMs) mirror mechanism disposed on a substrate,
wherein each MEMs mirror mechanism includes a mirror and means for supporting and moving the mirror between a first tilted position relative to the substrate, and a second tilted position relative to the substrate, according to said associated control signals generated by the controller, and
wherein the homogenous light generator, the spatial light modulator and the optical system are positioned such that, when the mirror of each said MEMs mirror mechanism is in the first tilted position, said mirror reflects an associated received homogenous light portion such that said modulated light portion is directed to the optical system, and when said mirror of each said MEMs mirror mechanism is in the second tilted position, said mirror reflects said associated received homogenous light portion such that said reflected received homogenous light portion is directed away from the optical system.