Electrophotography – Having particular structure – Modular or displaceable
Reexamination Certificate
2001-02-12
2004-04-13
Chen, Sophia S. (Department: 2852)
Electrophotography
Having particular structure
Modular or displaceable
C399S302000
Reexamination Certificate
active
06721521
ABSTRACT:
FIELD OF THE INVENTION
The present invention generally relates to an image forming apparatus wherein cyan (C), magenta (M), and yellow (Y) color image forming units for forming color images are provided on one side of an intermediate transfer medium (such as an intermediate transfer belt), and a black (Bk) toner image forming unit is provided on the other side of the intermediate transfer medium, and particularly relates to an image forming apparatus whose members can be maintained with ease without reducing the strength of an apparatus main body.
BACKGROUND OF THE INVENTION
Conventionally, a so-called tandem-type image forming apparatus is known as an image forming apparatus for forming color images using cyan (C) toner, magenta (M) toner, yellow (Y) toner and black (Bk) toner. In this type of image forming apparatus, image forming units for respective colors C, M, Y and Bk, each including a photoreceptor drum and a developing section, are arranged in order from the upstream side in a transport direction of a recording sheet, and respective color toner images formed on the photoreceptor drums are superimposed on a recording sheet in order, thereby forming a color image on the recording sheet.
In the described conventional tandem-type image forming apparatus, even when forming monochrome (black-and-white) images, it is required to go through not only Bk image forming processes but also C, M, and Y color image forming processes, and thus it is difficult to perform a high speed printing of a black-and-white image which is expected to be performed most frequently.
In response, for example, Japanese Unexamined Patent Publication No. 341617/1993 (Tokukaihel
5- 341617
, published on Dec. 24, 1993) discloses a structure which permits the formation of images at high speed almost as high as the speed of image forming apparatuses for forming only black-and-white images, wherein C, M and Y color recording processing sections adopting an intermediate transfer system are provided separately from a black-and-white recording processing section, and a tandem system is adopted between the color recording processing sections and the black-and-white recording processing section.
The described conventional image forming apparatus is arranged such that a door formed on the front face (the user's side) of the apparatus main body in an axial direction of a photoreceptor is capable of opening and closing so that various maintenance operations of developing units and image holding member units (such as a refill for toner consumed, etc.) can be performed. Specifically, with the door opened, a developing unit or an image holding member unit is pulled out of the apparatus by sliding it along the axial direction to allow an maintenance operation of the units such as a refill for toner consumed, etc., to be performed.
FIG. 10
shows an example of the image forming apparatuses adopting the above sliding mechanism. In this image forming apparatus, toner image forming stations
101
to
104
for respective colors C, M, Y and Bk are disposed so as to surround an intermediate transfer belt.
The toner image forming stations
101
and
104
respectively include image holding member units
101
a
and
104
a
, and developing units
101
b
and
104
b
. Further, each of the image holding member units
101
a
and
104
a
includes a photoreceptor for forming thereon an electrostatic latent image according to image data. The developing units
101
b
and
104
b
are provided for developing electrostatic latent images formed on respective surfaces of the photoreceptors using toner. Similarly, the toner image forming stations
102
and
103
are provided with the image holding member units and the developing units respectively. The respective image holding member units and the developing units of the toner image forming stations
101
to
104
are all slidable in the axial direction of the photoreceptors, and the front face of the apparatus main body is positioned at one end in the axial direction of the photoreceptors. Further, a door
105
is formed on the front face of the apparatus main body so as to be capable of opening and closing.
According to the foregoing structure, with the door
105
opened, by pulling a predetermined unit subjected to the maintenance operation in the axial direction of the photoreceptors, maintenance operations of the predetermined unit can be performed. Further, upon completing the maintenance operation, by pushing back the predetermined unit to its installation position in the apparatus main body, and closing the door
105
, a normal copying operation can be performed.
However, according to the structure shown in
FIG. 10
, all the toner image forming stations
101
to
104
slide along the axial direction, and thus the size of the door
105
formed in the axial direction is needed to be large. It is therefore required to form a large opening
106
for the door
105
in the support frame on the front face of the apparatus main body, which results in a reduction in strength of the main body apparatus. This problem becomes serious especially when using the apparatus with the main body apparatus tilted for a long time, as a damage on an element (mirror, LSU, etc.) which requires high precision may occurs due to the reduction in strength, thereby leading to a problem of a displacement of respective color toner images.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an image forming apparatus in which various maintenance operations of each unit can be performed while maintaining a sufficient strength of an apparatus main body, whereby degradation of image quality with life can be avoided for a long period of time.
In order to achieve the above object, an image forming apparatus of the present invention is characterized by including:
a plurality of image forming stations for respectively forming images in different colors,
wherein at least one of the plurality of image forming stations and rest of the plurality of image forming apparatuses are slidable in mutually different directions respectively through openings formed on an apparatus main body in respective sliding directions.
According to the above arrangement, the image forming stations corresponding to respective colors do not slide all in the same direction, but in two different directions. Here, the number of image forming stations which slide in each direction is not limited, and one or a plurality of image forming stations may slide in each direction. In any case, the image forming stations slide in mutually different directions through respective openings formed on the apparatus main body in respective sliding directions.
For example, in the case where one of the openings is formed in the axial direction of image holding members provided in the image forming stations, respective image forming stations being aligned in parallel in a direction orthogonal to the axial direction. In the conventional arrangement, all the image forming stations slide in the axial direction, and thus the opening formed in the axial direction is required to have a large size, and thus the reduction in strength of the apparatus main body having the opening cannot be avoided.
However, according to the arrangement of the present invention, by dividing the sliding direction of the image forming stations into two, for example, the number of image forming stations which slide in the axial direction of the image holding members provided in the image forming stations can be simply reduced. As a result, a size of the opening formed in the axial direction can be made smaller, and thus a reduction in strength of the apparatus main body can be suppressed. Therefore, even in the case where the apparatus is used for a long time with an apparatus main body tilted due to installation condition, the resulting displacement of each image forming station inside the apparatus can be prevented without causing a distortion in the apparatus main body. As a result, a displacement of images formed by the image forming stations for respective colors ca
Fukunaga Keizo
Kataoka Hiroshi
Taniguchi Tadasu
Chen Sophia S.
Sharp Kabushiki Kaisha
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