Electrophotography – Having particular structure – Modular or displaceable
Reexamination Certificate
2000-05-16
2002-04-02
Pendegrass, Joan (Department: 2852)
Electrophotography
Having particular structure
Modular or displaceable
C399S116000, C399S167000
Reexamination Certificate
active
06366748
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an image forming apparatus applicable as, for example, a color printer, a color copying machine, a color facsimile, and the like, and in particular, to a color electrophotographic apparatus forming a color image by using electrophotography and to an image forming unit used therefor.
BACKGROUND OF THE INVENTION
FIG. 7
is a cross-sectional view showing a conventional image forming unit taken along a plane through its center. The image forming unit shown in
FIG. 7
includes a photosensitive member, a charger, a developing means, a cleaning means, a box, and the like.
In
FIG. 7
, numeral
100
denotes an image forming unit, which is formed integrally as one unit including a photosensitive member
110
and process elements provided therearound. Each element includes the following parts.
Numeral
121
denotes a charger for homogeneously charging the photosensitive member
110
, and
123
denotes a developing means including a developing roller
122
. Numeral
125
denotes a toner hopper containing toner
124
. The toner
124
is supported on the surface of the developing roller
122
of the photosensitive means
123
and develops the photosensitive member
110
. Numeral
126
denotes a cleaning means for removing toner remaining on the surface of the photosensitive member
110
, which includes a rubber cleaning blade
127
and a waste toner case
128
for containing waste toner. Numeral
129
denotes an exposure window opening for a laser beam to enter the image forming unit
100
.
FIG. 8
is a perspective view showing a drive side flange of the photosensitive member with which a gear for driving to rotate the photosensitive member is integrated.
As shown in
FIG. 8
, at one end of the photosensitive member
110
, the drive side flange
111
is fixed. The drive side flange
111
is formed integrally into one unit with a gear portion
111
A receiving a rotation driving force from the apparatus main body. On the other end of the photosensitive member
110
opposing to the drive side flange
111
, a non-drive side flange (not shown) is fixed. The photosensitive member
110
is held in a box
130
by a photosensitive member axis
112
supporting while rotating each flange attached to the photosensitive member
110
at the axis of the photosensitive member
110
. Furthermore, the photosensitive member
110
is positioned at the image forming position of the apparatus main body at both ends of the photosensitive member axis
112
. Moreover, numeral
131
denotes washers provided at both ends of the photosensitive member
112
so that the photosensitive member axis
112
is not prevented from dropping from the box
130
. Furthermore, at the drive side flange
111
, a metal plate
113
is provided in contact with both the photosensitive member
110
and the photosensitive member axis
112
so that the photosensitive member
110
conducts to the apparatus main body.
Also in a color printer, a color copying machine, a color facsimile, and the like, similar to monochrome ones, there is a demand towards a high quality image, small size and low cost by producing the image forming apparatus by forming each image forming member as one unit, thus facilitating the handling. Above all, in order to improve the image quality, it is required to improve the positioning accuracy and the rotating accuracy of the photosensitive member of each image forming unit in the photosensitive member at the image forming position.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an image forming unit having a simple structure, capable of reduction in size and weight, and realizing a high quality image, and an image forming apparatus capable of improving the positioning and the rotating accuracy of the photosensitive member at the image forming position by using the image forming unit.
In order to attain the above-mentioned object, an image forming unit according to the present invention includes a photosensitive member on the surface of which an electrostatic latent image is formed; a charger for charging the photosensitive member; a developing means for developing the electrostatic latent image into a visible image; and a box for supporting the photosensitive member, the charger and the developing means; and wherein a first flange that is integrally formed into one unit including a positioning part with respect to the image forming apparatus main body for positioning the photosensitive member at the image forming position of the image forming apparatus main body and a rotation engaging portion for receiving a rotation driving force from the image forming apparatus main body is attached to at least one end of the photosensitive member. According to this configuration of the image forming unit, it is possible to lighten and simplify the photosensitive member, to support the photosensitive member axis by the image forming apparatus main body, and to rotate the photosensitive member easily by the axis itself. Therefore, positioning accuracy and rotating accuracy of the photosensitive member are improved. As a result, it is possible to align colors accurately, which is important when forming a color image. Thus, a high quality image can be obtained.
Furthermore, it is preferable in the image forming unit according to the present invention that the positioning part is a hole or a concave portion provided concentrically with respect to the photosensitive member axis. According to such a preferable configuration, it is possible to guide the positioning means of the image forming apparatus main body to the positioning part easily and to carry out the positioning by the photosensitive member axis. As a result, it is possible to reduce rocking in rotation of the photosensitive member at the time of rotation driving, and thus a high quality image can be obtained.
Furthermore, it is preferable in the image forming unit according to the present invention that a second flange that is integrally formed into one unit including a positioning part for positioning with respect to the image forming apparatus main body is attached to the other end of the photosensitive member opposing the first flange. According to such a preferable configuration, it is possible to simplify the structure of the photosensitive member. Furthermore, since the positioning parts of both of the first flange and the second flange with respect to the image forming apparatus main body are provided in the flange main body, the photosensitive member can be positioned at the image forming position of the image forming apparatus main body at high accuracy. Furthermore, in this case, it is preferable that the second flange is provided with a rotation engaging portion for conveying the rotation driving force from the image forming apparatus main body. According to such a preferable configuration, since it is possible to convey the rotation driving force of the photosensitive member to the positioning means of the image forming apparatus main body that engages the second flange, the positioning means is allowed to rotate together with the second flange so as to inhibit the sliding between the rotation engaging portion of the second flange and the positioning means. As a result, it is possible to prevent the positioning part of the second flange from being deformed and, at the same time, to prevent mislocation in positioning the photosensitive member, and a high quality image can be obtained. Furthermore, in this case, it is preferable that both ends of the photosensitive member are rotatably bearing supported by the box in the outer circumference of the first and second flanges. According to such a preferable configuration, it is possible to use the side face of the flange effectively. In particular, by positioning the photosensitive member at the axis of the photosensitive member of each flange, the rotation accuracy of the photosensitive member can be increased. Thus, the accuracy in aligning colors can be enhanced, thus to obtain a high quality image. Furthermore, it is preferable
Katakabe Noboru
Suzuki Hiroyuki
Takeuchi Keizou
Tani Shigemitsu
Matsushita Electric - Industrial Co., Ltd.
Merchant & Gould P,C,
Pendegrass Joan
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