Incremental printing of symbolic information – Light or beam marking apparatus or processes – Scan of light
Reexamination Certificate
1999-09-03
2001-05-29
Le, N. (Department: 2861)
Incremental printing of symbolic information
Light or beam marking apparatus or processes
Scan of light
C347S256000
Reexamination Certificate
active
06239828
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image formation device such as a laser beam printer, an LED array printer and a digital copying machine for forming a multicolor image using arrayed light sources, particularly relates to an image formation device which can be miniaturized, of which the quality of an image is uniform, which can form a high resolution of color image at high speed and in which the deterioration of color registration can be reduced even if the relative position of a light source and an optical element is dislocated.
2. Description of the Related Art
A conventional type image formation device emits a laser beam modulated according to a picture signal from a laser beam source for example, scans the laser beam in a horizontal scanning direction using a polygon mirror, exposes a photoconductor drum rotated in a vertical scanning direction by the laser beam scanned using the polygon mirror, forms an electrostatic latent image on the photoconductor drum by the above exposure scanning and implements the recording of an image based upon the electrostatic latent image.
However, according to the light deflection type image formation device using a polygon mirror, as the speedup of the rotational speed of the polygon mirror is limited, the speedup of recording rate is limited.
To speed up the recording rate of an image formation device, an image formation device using arrayed light sources for emitting plural light beams by driving according to the pattern of a recorded image without a polygon mirror is being studied.
A conventional type image formation device not using a polygon mirror is disclosed in Japanese Published Unexamined Patent Application No. Hei 9-193450 for example.
FIG. 21
shows the image formation device. The image formation device is provided with a laser array
100
having plural laser beam emitting elements
100
a
arrayed in a horizontal scanning direction, a photoconductor drum
105
exposed by plural laser beams
101
emitted from each laser beam emitting element
100
a
on which an electrostatic latent image according to a picture signal is formed by moving the photoconductor drum in a vertical scanning direction differently from the laser array
100
, a field lens
102
as a projection optical system for focusing plural laser beams
101
emitted from plural laser beam emitting elements
100
a
on a common focus
106
, an imaging lens system
107
arranged on the focus
106
as a projection optical system for imaging the plural laser beams
101
on the photoconductor drum
105
and forming plural beam spots on the photoconductor drum
105
, a half mirror
103
arranged between the field lens
102
and the imaging lens system
107
, a photo detecting element
104
for detecting the luminous energy of a laser beam reflected by the half mirror
103
and a control part for controlling the driving condition of each laser beam emitting element
100
a
based upon a signal detected by the photo detecting element
104
.
Hereby, as plural laser beam emitting elements
100
a
can be simultaneously driven according to the pattern of a recorded image, a recording rate can be sped up. As the laser beam emitting elements
100
a
can be arranged in high density, a high resolution of image can be acquired. Also, as each laser beam emitting element
100
a
can correct luminous energy, luminous energy can be kept uniform and a uniform image can be acquired.
There is known a multicolor image formation device using a light emitting element array in which multiple light emitting elements are arranged corresponding to the scanning width of an output image as a light source for projecting by an optical system and forming an image on a photoconductor as disclosed in Japanese Published Unexamined Patent Application No. Hei 8-181871 for example.
FIGS. 22A and 22B
show the conventional type multicolor image formation device. The multicolor image formation device is provided with plural light emitting diode (LED) arrays
101
Y,
101
M,
101
C and
101
K respectively provided corresponding to yellow (Y), magenta (M), cyan (C) and black (K) in which each LED is arranged in the direction of the width of an image (a horizontal scanning direction), driving circuits
10
Y,
100
M,
100
C and
100
K for driving each LED array
110
Y,
10
M,
101
C and
101
K based upon Y image data, M image data, C image data and K image data respectively corresponding to Y, M, C and K and emitting plural light beams
102
y
,
102
m
,
102
c
and
102
k
, photoconductor drums
104
Y,
104
M,
104
C and
104
K arranged along a traveling route
105
of paper P corresponding to each color and rotated in a direction shown by an arrow (in a vertical scanning direction) and projection optical systems
103
Y,
103
M,
103
C and
103
K for respectively projecting and imaging plural light beams
102
y
,
102
m
,
102
c
and
102
k respectively from the LED arrays
101
Y,
101
M,
101
C and
101
K on the photoconductor drums
104
Y,
104
M,
104
C and
104
K as shown in FIG.
22
A.
The LED array
101
is attached to a case
106
via a mounting plate
107
as shown in FIG.
22
B and the projection optical system
103
is attached to the case
106
via a mounting member
108
so that it is located immediately under the LED array
101
. Hereby, as plural LEDs can be simultaneously driven according to the pattern of a recorded image, a color image can be recorded at high speed.
However, according to the conventional type image formation device, if the laser array, the LED array, the projection optical system and a luminous energy detecting system are provided for every color to form a color image, there is a problem that the device is large-sized.
According to the conventional type multicolor image formation device, as the projection optical system is independent for every color, the exposed position of each color is dislocated when the position of the LED array and an optical element changes because of the change of temperature, vibration and the like and so-called color registration is deteriorated. As a result, a problem arises that the quality of an output image is deteriorated.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide an image formation device which is low-priced, can be miniaturized and can form a high resolution of color image at high speed.
Also, another object of the present invention is to provide an image formation device which can be miniaturized and can form a high resolution of color image of which the quality is uniform at high speed.
Also, the other object of the present invention is to provide an image formation device wherein the deterioration of color registration can be reduced even if the relative mounted position of a light source and an optical element is dislocated.
To realize the above object, the present invention provides an image formation device based upon an image formation device for forming a color image composed of plural colors and characterized by being provided with plural light source arrays provided corresponding to plural colors and having plural light emitting elements arrayed at least in a horizontal scanning direction for emitting plural light beams modulated based upon a picture signal corresponding to the plural colors from the plural light emitting elements, plural image carriers provided corresponding to the plural colors and exposed by the plural light beams from the plural light source arrays on which a latent image is formed by moving the image carrier in a vertical scanning direction, a projection optical system for imaging the plural light beams from the plural light source arrays focused on a common focus on the plural image carriers and forming the above latent image.
According to the above configuration, the optical system is miniaturized by imaging plural light beams emitted from plural light emitting elements corresponding to each color on the plural image carriers by a common projection optical system and even if the relative mounted position of the light sour
Ito Masao
Yamaguchi Shoji
Fuji 'Xerox Co., Ltd.
Le N.
Oliff & Berridg,e PLC
Pham Hai C.
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