Imaging diode array and system

• US 5,121,146 A
• Filed: 12/27/1989
• Issued: 06/09/1992
• Est. Priority Date: 12/27/1989
• Status: Expired due to Fees

• Current Assignee: Advanced Imaging Products Corporation
• Original Assignee: AM International Incorporated (Paragon Corporate Holdings, Inc.)
• Inventors: Smith, Ronald S., Kubert, Vincent T., Duchesne, Mark F., Olenski, Matthew J.
• Primary Examiner(s): Fuller, Benjamin R.
• Assistant Examiner(s): Gibson, Randy W.
• Application Number:
  US07/457,433
• Time in Patent Office: 895 Days
• Field of Search: 346/108, 346/154, 346/155, 346/160, 346/110 R, 346/107 R, 346/76 PH, 340/783, 357/17, 372/35, 372/43
• US Class Current: 347/238
• CPC Class Codes: G06K 15/1247 using an array of light sources, e.g. a linear array

Abstract

A large scale LED exposure array and system for printers, and unique methods of inputting data to and operating such an array, is disclosed. The array can be loaded and refreshed with data information at rates compatible with high speed printing, and forms part of an electronic image forming and handling system which can load and refresh an exposure array at variable speeds of at least 100 to 300 ft./min. The system includes compensation for differences in illuminating capability of individual LEDs in a large array, by introducing modifications in LED on-time which are centered with respect to the incremental area of the photoreceptor on which a pixel is to be formed, and to compensate for changes in pixel exposure time with increase in speed of the photoreceptor. Also disclosed are an LED configuration which can emit high energy in a controlled pattern to give a desired pixel spot on a photoreceptor, and an arrangement for mounting the array to maintain each light emitting spot in focus on the photoreceptor surface, although a wide array is employed.

Claims

1. An array of light spot generators for selectively exposing uniformly sized pixel areas within an image area to produce an image comprised of pixels, comprising

a plurality of light emitting diodes each capable of selectively generating a light beam of dot-like configuration,

a mounting block supporting said diodes in closely packed adjacent positions such that light beams therefrom can be focused to illuminate adjacent pixel areas in an image plane,

said mounting block including means organizing said diodes into separate modules containing a predetermined fraction of a total of said array,

driving means connected to each of said diodes to cause the same to illuminate,

data storage registers for holding data to control said driving means to determine those pixel areas to be illuminated by said diodes,

data input means connected in parallel to said data storage registers for inputting data to the separate modules and adapted to load data serially into each data storage registers in a same module,

clock means controlling transfer of data from said data input means to said data storage registers, and

latch means for controlling the connection of said data storage registers to said driving means.

2. An array of light spot generators as defined in claim 1, wherein

said data input means includes memory means for containing compensation information for the individual diodes and adapted to modify writing data into compensated driving data for each diode driving means.

4. An array as defined in claim 1, including

means for simultaneously changing a light emission intensity of all said diodes.

5. An array as defined in claim 1, wherein each of said diodes comprises a semiconductor junction shaped to produce a projected light spot of generally rectangular configuration with concave opposite sides.

3. An array as defined in 1, including

a timebase control means acting on said latch means to connect said latch means sequentially to said driving means.

6. A light emitting diode for generating a light pattern of predetermined shape, comprising

an elongated anode member,

a semiconductor member attached to said substantially surrounding said anode member,

a cathode connected to said semiconductor,

said semiconductor member having a face from which light energy is emitted,

said face being characterized by side and central regions of approximately equal height and intermediate regions of lesser height between said side and central regions and said cathode covering a portion of said central region,

whereby the light pattern from said face is resolved to a generally rectangular shape with concave sides.

7. A light diode as defined in claim 6, wherein said intermediate regions of said face have generally arcuate top and bottom edges.

8. An array of LED light spot generators for selectively exposing uniformly sized pixel areas within an image area on a rotating cylindrical photoreceptor surface to produce an image comprised of pixels on the surface, comprising

an elongated cathode member common to all LEDs of said generators

a plurality of closely spaced light emitting semiconductor junctions along said common cathode member each capable of generating a light pattern of a same predetermined shape, said junctions all having a common shape,

said semiconductor junctions having a face from which light energy is emitted, which face is characterized by side and central regions of approximately equal height and intermediate regions of lesser height,

a separate anode fixed to said face and covering a portion of said central region,

whereby light patterns from said face of said plurality of junctions are resolved each to a same generally rectangular shape with concave sides to effect side-by side merging of the light patterns when projected onto the photoreceptor surface;

means for supporting said array extending across the photoreceptor surface whereby exposure of the pixel areas by the shaped light energy results in adjoining and approximately square exposed pixel images on the photoreceptor surface.

9. An array of light spot generators for selectively exposing uniformly sized pixel areas within an image area on a rotating cylindrical photoreceptor surface having cylindrical bearer bands at its sides to produce an image comprised of pixels on the surface, comprising

a plurality of light emitting means each capable of selectively generating a light beam of dot-like configuration,

a mounting block supporting said light emitting means in closely packed adjacent positions such that the light beams therefrom can be focused to form adjacent pixel areas in an image plane,

means movably supporting said mounting block extending transversely of the photoreceptor surface to direct light from each of said light emitting means in a row across the surface along a radius of said cylindrical photoreceptor surface,

strip members on opposite sides of said mounting block facing the bearer bands, and

spring means urging said strip means into contact with the bearer bands to maintain spacing of the array to the photoreceptor surface.

10. An array as defined in claim 9,

said block supporting means comprising a leaf spring attached at one edge to said mounting block and acting to swing said array toward said photoreceptor surface.

11. A method of compensating an output light pattern from a linear array of spaced but closely packed semiconductors comprising the steps of

mounting the semiconductors in closely spaced side-by-side relation of a common cathode of predetermined length and height, said semiconductors being elongated in a direction of a length of the cathode and being shaped to present a light emitting face which is of greater height at end regions of said face and a middle region of said face and of reduced height in intermediate areas therebetween,

attaching individual anodes to the face of the middle region of each of said semiconductors and thereby covering a portion of the light emitting area of each said semiconductors such that an effective area of the middle region approximately equals the intermediate areas,

whereby the greater height of the end regions and the middle region compensates for a reduced light emitting area covered by the anodes and resulting from the space between adjacent semiconductors, and the pattern of light from an energized semiconductor onto a photoreceptor surface is approximately rectangular and the light patterns from adjacent semiconductors will be adjoining on the photoreceptor surface.