Electrophotography – Having particular structure
Reexamination Certificate
2000-05-10
2002-10-29
Ngo, Hoang (Department: 2852)
Electrophotography
Having particular structure
C399S393000
Reexamination Certificate
active
06473576
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image forming apparatus such as a copying machine, a printer or a facsimile apparatus and to an image forming apparatus having the functions of these apparatuses.
2. Description of the Related Art
Recently, there has been proposed an image forming apparatus such as a copying machine, a printer or a facsimile apparatus, as well as image forming apparatus having the functions of these apparatuses, which uses a so-called flat bed type original tray and a stationary optical system as the reading means.
Regarding such an image forming apparatus, there have been proposed various types of sheet conveying paths for conveying a sheet to the image forming section and for discharging it to the exterior of the apparatus. For example,
FIG. 10
is a side sectional view which shows an image forming apparatus
100
serving as a copying machine.
The image forming apparatus comprises an image forming section including a reader section
102
provided above a casing
101
and adapted to optically scan an original image and read it to generate image information, a laser scanner unit
103
provided below the reader section
102
and adapted to reproduce the original image on a sheet P in accordance with the image information of the original generated in the reader section
102
, a process cartridge
105
, and a fuser
106
. A sheet supporting section
114
is arranged on the rear side of the apparatus main body (the right hand side in
FIG. 10
) and is adapted to support a plurality of sheets P, such as copying paper. The apparatus further comprises a manual sheet supply section
113
for manually supplying sheets P one by one, a sheet feeding mechanism
104
equipped with a feeding roller
104
a for feeding the sheets P supplied from the sheet supporting section
114
or the manual sheet supply section
113
to the process cartridge
105
, and sheet conveying means consisting of various rollers for conveying the sheets P.
In the image forming apparatus
100
, the sheets P supplied from the sheet supporting section
114
or the manual sheet supply section
113
are separated and fed one by one by the sheet feeding mechanism
104
at the bottom, and supplied to the process cartridge
105
, where a toner image formed by the process cartridge
105
is transferred to the sheet.
After this, the image is supplied to the fuser
106
, where the toner image is fixed to complete the image forming process, and then the sheet with the image is discharged to the exterior of the apparatus by the pair of rollers of the sheet discharge section
115
.
This image forming apparatus
100
, in which the sheet conveying path is short, provides various advantages. For example, the time for copying the first sheet can be shortened, jamming does not easily occur, a reduction in the size of the apparatus is possible, and the apparatus is inexpensive.
In the image forming apparatus
100
shown in
FIG. 10
, the sheet supporting section
114
supports the sheets P in an inclined position, and holds substantially the central portion of the sheets, so that it is difficult to supply a large number of sheets. Further, dirt is liable to adhere to the sheets P, and dust is liable to accumulated thereon.
In addition, in the image forming apparatus
100
, all of the means for supplying the sheets P, namely the sheet supporting section
114
and the manual sheet supply section
113
, are provided on the rear side of the apparatus, so that depending upon the apparatus installation condition, the supplying of the sheets P may be difficult.
Thus, it is required of this image forming apparatus
100
to make it possible to supply a large quantity of sheets, to provide additional sheet supplying means on the front side of the apparatus, etc. More specifically, it might be possible, for example, to add to the front side of the apparatus a cassette feeding mechanism using a sheet loading cassette capable of supplying a large quantity of sheets.
FIG. 11
shows an example in which, while maintaining the basic construction of the image forming apparatus of
FIG. 10
, a sheet loading cassette (hereinafter simply referred to as a sheet cassette)
107
is attached to the bottom front portion of the apparatus main body, and a sheet feeding mechanism is provided from the sheet cassette
107
. The components which are the same as those shown in
FIG. 10
are indicated by the same reference numerals.
In this image forming apparatus
200
shown in
FIG. 11
, there is a sheet feeding path
108
from the downstream side of the cassette
107
to the image forming section, and the sheets fed from the downstream side of the sheet cassette
107
are caused to make a U turn at the sheet feeding path
108
and conveyed to the process cartridge
105
.
The sheet cassette
107
is capable of loading and accommodating a large number of sheets, and is attached to casing
101
A such that the loaded sheets are substantially horizontal. Further, the sheet cassette
107
is equipped with a cover
107
a
for preventing dust and other contaminants from adhering to the loaded sheets.
Due to this arrangement, in the image forming apparatus
200
, sheet feeding by way of two sheet feeding paths in two directions is realized. Further, the arrangement provides the following advantages: the time for copying the first sheet can be shortened, jamming does not easily occur, etc. At the same time, it is possible to supply a large number of sheets to the sheet cassette
107
and to prevent dirt, dust and other contaminants from adhering to the sheets loaded in the sheet cassette
107
.
However, in the image forming apparatus
200
shown in
FIG. 11
, it is necessary to join the sheet feeding paths from the two directions. Further, it is necessary to add a pair of rollers
109
in order to prevent a deterioration in conveying power due to the rounding of the sheet feeding path
108
from the sheet cassette
107
. Thus, as is apparent from comparison with
FIG. 10
, the length of the sheet feeding path from the sheet feeding mechanism
104
to the process cartridge
105
increases.
As a result, in the image forming apparatus
200
, the depth of the casing
101
A increases, the size of the entire apparatus increases, and the installation area increases. Further, since the sheet feeding path
108
from the cassette
107
is situated considerably deep in the apparatus, jam processing for removing a jammed sheet when it occurs is not easy to perform.
To cope with the above problem, a construction has been proposed in which a door is provided on the right or left-hand side of the casing
101
A and in which this door is opened to take in or out the process cartridge
105
. However, this involves an increase in the area occupied by the apparatus in use, so that it is actually necessary to secure a wide space for the installation of the apparatus, which is not desirable.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above problems. It is accordingly an object of the present invention to provide an image forming apparatus which is equipped with a sheet supporting means with satisfactory operability and which can be reduced in size while shortening the time for forming the first image, reducing jam generation and achieving a reduction in cost. More specifically, there is provided, in accordance with the present invention, image forming apparatus comprising an image reading means for reading an image on an original, image forming means for forming an image from image information read by said image reading means, and a sheet feeding means for feeding sheets to said image forming means, said sheet feeding means comprising a sheet supporting portion for supporting sheets on which images are to be formed and a feeding portion for feeding the sheets supported in the sheet supporting portion to the image forming means and arranged between the image reading means and the image forming means.
Further objects, features and advantages of the present invention will become apparent from
Kimura Naomasa
Koshimizu Yoshiyuki
Mori Hideki
Mori Masakazu
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