Incremental printing of symbolic information – Light or beam marking apparatus or processes – Scan of light
Reexamination Certificate
1997-12-18
2001-08-21
Le, N. (Department: 2861)
Incremental printing of symbolic information
Light or beam marking apparatus or processes
Scan of light
C347S257000, C347S238000
Reexamination Certificate
active
06278475
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a solid-state scanning-type optical writing device for writing an image (latent image) on the surface of an image carrying member such as a photosensitive member, photosensitive paper or the like using a plumbus lanthanum zirconate titanate (PLZT) light shutter array, light-emitting diode (LED) array or the like.
2. Description of the Related Art
Heretofore, there have been various proposed optical writing devices which control the ON/OFF switching of each single pixel via a plurality of light signal emitting elements to form an image (latent image) on the surface of an image carrying member such as an electrophotographic photosensitive member, silver salt film, printing paper using silver salt material and the like. Light shutter elements such as PLZTs and the like, and light-emitting elements such as LEDs and the like have been proposed as light signal emitting elements. The light signal emitting elements are arranged in a main-scan direction, and form a light signal emitting array.
To form a full color image by using aforementioned type of light signal emitting elements, consideration may be given to providing three light signal emitting arrays so that the light signal emitting arrays correspond to red (R), green (G), and blue (B), respectively. Furthermore, consideration also may be given to arraying the light signal emitting arrays in the sub-scan direction. A disadvantage arises, however, as to the degree of precision with which light from said mutually independent light signal emitting elements irradiates the surface of the image carrying member.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an optical writing device capable of reproducing high quality images.
Another object of the present invention is to provide an optical writing device capable of reproducing images with excellent precision.
An object of the present invention is to provide a solid-state scanning-type optical writing device capable of reproducing high quality images with excellent precision when forming color images using light signal emitting arrays arranged in the sub-scan direction such that light emission color of each said array is different.
To achieve at least one of aforesaid objects, a light signal emitting device of the present invention comprises:
a plurality of light signal emitting arrays each of which includes a plurality of light emitting elements arranged in a main-scan direction, the light signal emitting arrays being disposed in a sub-scan direction orthogonal to the main-scan direction; and
an adjuster which adjusts a position of at least one of the light signal emitting arrays, said adjuster adjusting the position with respect to the sub-scan direction. When the light signal emitting arrays are arranged on a base, the base can be accommodated in a single housing such that all light signal emitting arrays can be positionally adjusted in the sub-scan direction. Furthermore, when each light signal emitting array is arranged on a different base, and each bese is mounted in a respectively independent housing, at least one said housing may be positionally adjustable in the sub-scan direction.
According to another aspect of the present invention, an optical writing device comprises:
a first optical system for emitting light signals of first color, the first optical system comprising a first array of light signal emitting elements and first lens, the light signal emitting elements of the first array being arranged in a main-scan direction orthogonal to the sub-scan direction, the first lens being disposed at an image side of the first array and requiring a first length to focus the light signals of first color; and
a second optical system, provided at one side of the first optical system with respect to the sub-scan direction, for emitting light signals of second color, the second optical system comprising a second array of light signal emitting elements and lens, the light signal emitting elements of the second array being arranged in the main-scan direction, the second lens being disposed at an image side of the second array and requiring a second length to focus the light signals of second color which has a wavelength greater than that of said first color,
wherein the first optical system and the second optical system are set in accordance with the first length and the second length, respectively. In the optical writing device of the present invention, the distance between each light signal emitting array and the surface of the image carrying member may differ in accordance with the wavelength of the light emission color, or a focus position-correcting optical element may be provided between the light signal emitting array and the surface of the image carrying member. Since the image forming distance of each color light differs in accordance with the wavelength, having the distance between each light signal emitting array and the surface of the image carrying member differ according to the wavelength of the light emission color allows for accurate focus positioning on the surface of the image carrying member for each color, as well as highly accurate and high quality color image reproducibility. Interposing a focus position correcting optical element between an optical chip array and the surface of the image carrying member to adjust the focus position in accordance with said wavelength or relative to the curvature of the surface of the image carrying member in the sub-scan direction allows highly accurate and high quality color image reproducibility.
These and other objects, advantages and features of the invention will become apparent from the following description thereof taken in conjunction with the accompanying drawings which illustrate specific embodiments of the invention.
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Le N.
McDermott & Will & Emery
Minolta Co. , Ltd.
Pham Hai C.
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