Active solid-state devices (e.g. – transistors – solid-state diode – Incoherent light emitter structure – With reflector – opaque mask – or optical element integral...
Reexamination Certificate
1999-07-12
2001-02-13
Saadat, Mahshid (Department: 2815)
Active solid-state devices (e.g., transistors, solid-state diode
Incoherent light emitter structure
With reflector, opaque mask, or optical element integral...
C257S088000, C257S095000, C257S294000, C359S738000, C438S029000
Reexamination Certificate
active
06188086
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to a light emitting diode (LED) array for optical printers, digital copiers, facsimile machines, etc. More particularly, the present invention is directed to a light emitting diode array in which a plurality of light emitting elements are disposed along a curved line in order to reduce distortion.
2. Discussion of the Background
A light emitting diode array includes a plurality of light emitting elements which are disposed in at least one row. Such a light emitting diode array is used in an optical printer, a digital copier, or a facsimile machine. The light emitting diode array is more reliable for use under vibrations and noises than a laser beam printer. The light emitting diode array is also suitable for miniaturizing an optical image forming apparatus, as the light emitting diode array does not need a scanning mechanism such as a polygonal mirror as is required by the laser beam printer.
FIG. 8
illustrates a base
80
having mounted thereon a conventional light emitting diode array
70
with two lens arrays
90
and
100
for use in an optical image forming apparatus. The light emitting diode array
70
comprises a plurality of light emitting diodes
71
which are disposed in one row and on a straight line at the same predetermined distance from each other. The straight line on which the light emitting diodes
71
are disposed is perpendicular to an optical axis of lenses
91
and
101
in the lens arrays
90
and
100
.
A pattern of light emission from the light emitting diode array
70
is focused on a photosensitive body such as a photoconductive drum through the two lens arrays
90
and
100
so as to form an image on the photosensitive body. However, the above-mentioned optical image forming apparatus with light emitting diode array
70
and lens arrays
90
and
100
has a drawback in that light loss occurs at connecting portions
91
a
,
101
a
between each lens
91
and
101
, and in that flared light occurs on each lens
91
and
101
. As a result, a pattern of light emission onto the photosensitive body becomes uneven.
SUMMARY OF THE INVENTION
Accordingly, the present invention provides for a novel light emitting diode array which can solve the aforementioned drawbacks, and, thus, an object of the present invention is to provide for a novel light emitting diode array in which a pattern of light emission onto the photosensitive body from the light emitting diode array and the lens array is uniform.
It is another object of the present invention to provide for a novel light emitting diode array in which the occurrence of light loss and flared light is prevented.
These and other objects are accomplished by a light emitting diode array for use in an optical image forming apparatus which has the LEDs arranged along a curved line. Light from the LEDs along the curved line is focused through a lens on a light receiving surface such as a photoconductive drum. This forms a latent image on the photoconductive drum which can be developed using conventional toner developing techniques into a toner image which is transferred onto a page in a conventional manner. The LEDs are edge emitting type LEDs or alternatively surface emitting type LEDs. The LEDs at the ends of the LED array are aimed toward and project light towards the center of the lens and also towards the optical axis of the lens.
The lens used by the present invention can include one lens array or two lens arrays in parallel. If two lens arrays are used, each of the lenses include an aspherical surface. The arrangement of the invention can be used in an image forming system such as a copier, printer, or facsimile machine.
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patent: 4654629 (1987-03-01), Bezos et al.
patent: 4791494 (1988-12-01), Schaefer
patent: 4922218 (1990-05-01), Watanabe et al.
patent: 5070369 (1991-12-01), Mahoney et al.
patent: 5418384 (1995-05-01), Yamana et al.
patent: 5444520 (1995-08-01), Murano
patent: 5838024 (1998-11-01), Masuda et al.
patent: 5962874 (1999-10-01), Masuda et al.
Masuda Kouji
Seizo Suzuki
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Ricoh & Company, Ltd.
Saadat Mahshid
Wilson Allan R.
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