Electrophotography – Having particular structure – Modular or displaceable
Reexamination Certificate
2000-12-20
2002-10-08
Grainger, Quana M. (Department: 2852)
Electrophotography
Having particular structure
Modular or displaceable
Reexamination Certificate
active
06463231
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a printer device which includes image formation means, a lower body and an upper body which is shifted upward with respect to the lower body so as to be opened, and more particularly, to a tandem-type color printer device including a plurality of image formation units which are detachable from and attachable to the printer device.
2. Description of the Related Art
Conventionally, a well-known printer device includes at least one image formation unit which is detachable from and attachable to the printer device, a lower body and an upper body which is lifted upward with respect to the lower body for the maintenance sake.
FIG. 21
shows an outside perspective view of a conventional monochrome printer device (image formation device). In the illustration, a printer device
1
comprises a roof
2
, which forms an upper body, and a lower body
3
. The roof
2
includes a paper outputting section
5
from which a paper is output onto the roof
2
, and a paper outputting tray
6
for outputting papers one on top of another. The lower body
3
includes a front cover
7
which can be opened and closed in the front section of the lower body
2
, and a paper cassette
8
which is detachable from and attachable to the lower body
3
. An MPF (Multi Paper Feeder) tray
9
which can be contained in the lower body
3
is arranged on the right side of the printer device
1
. An operational display section
4
for inputting information to the printer device
1
or for displaying the state of printer device
1
is arranged on the right upper side of the printer device
1
.
In such a printer device
1
, the roof
2
is opened in a direction shown with an arrow B centrically at a rotational axis A, when clearing a jam occurring in the printer device or carrying out a maintenance operation.
FIG. 22
shows a cross sectional view of the printer device together with the internal structure thereof. As illustrated in
FIG. 22
, the printer device
1
comprises: a paper cassette
8
which is detachable from and attachable to the printer device
1
; a paper feeding roller
12
which sequentially feeds papers contained in the paper cassette
8
; a pair of suspension rollers
13
which suspend a received paper and send the paper to an image formation section
11
at a predetermined timing, in association with a pair of paper outputting rollers
18
; a fixation unit
14
which fixes a toner image onto a paper; the pair of paper outputting rollers
18
(a driving roller
18
a
and a driven roller
18
b
) which output the paper onto which the toner image is fixed; and an operational display section
4
for performing various settings for the printer device
1
or displaying the state of the printer device
1
.
In the image formation section
11
, a charger
25
uniformly charges electric charges onto the circumferential surface of a photosensitive drum
23
. A printing head
26
selectively exposes the circumferential surface of the photosensitive drum
23
based on printing data The electric potential of a portion of the photosensitive drum
23
, whose circumferential surface is exposed, is lower than that which is charged with electricity. Hence, an electrostatic latent image is formed on the circumferential surface of the photosensitive drum
23
. A developing unit
27
transfers internally contained toner onto the low potential section of the photosensitive drum
23
through a developing roller
27
a
so as to develop the electrostatic latent image. A transfer unit
28
transfers the toner image on the photosensitive drum
23
onto a paper to be conveyed, with an electric field whose polarity is opposite to that of the toner.
The photosensitive drum
23
, the charger
25
, the developing unit
27
, the transfer unit
28
, a cleaner
24
, etc. which are included in the image formation section
11
are included in the lower body
3
, while the printing head
26
is arranged on the roof
2
as the upper body.
The roof
2
can be opened and closed centrically about a hinge section
15
in both directions as shown with arrows B and B′. At this time, the printing head
26
and the driven roller
18
b
are incorporated with the roof
2
so as to be opened and closed altogether. The roof
2
shown with a straight line in
FIG. 22
is in the state where it is closed, while the roof
2
shown with a broken line is in the state where it is opened. To keep the roof
2
opened, a body locking mechanism
16
is arranged. The body locking mechanism
16
is composed of a hook
17
a
arranged on the lower body
3
and an engagement section
17
b
which is arranged on the roof
2
and engaged with the hook
17
a.
The image formation section
11
mainly forms a cartridge CT as an image formation unit which is detachable from and attachable to the lower body
3
. The cartridge CT includes the first cartridge CT
1
comprising the photosensitive drum
23
and the cleaner
24
, etc, and the second cartridge CT
2
including the developing unit
27
. The cartridge CT is dividable into the cartridges CT
1
and CT
2
. In the state where the roof
2
is opened, the cartridges CT
1
and CT
2
can be detached from and attached to a predetermined installation section of the lower body
3
. If a photosensitive drum
23
is deteriorated or if toner ran out, for example, the cartridge CT
1
or CT
2
can be replaced with a new cartridge, or other expendable supplies can be provided as needed, thus achieving the machine maintenance operation of the printer device.
In recent years, color printer devices (color image formation devices) are widely used, and various color printing methods are employed. For example, according to one technique, a plurality of developing units are arranged adjacent to the circumferential surface of one photosensitive drum, and toner images are sequentially formed on the surface of the drum (technique (I)). There is another technique (II), which employs an intermediate transcription medium in a drum-like form. A plurality of image formation units are arranged in a predetermined direction, and toner images are sequentially output on one top of another on a paper so as to form an image (what is so-called a tandem-type printing technique).
In the above technique (I), it is necessary to use a large-sized photosensitive drum, and it is difficult to form an image formation section in one unit, resulting in low printing performance. In the above technique (II), because the intermediate transcription medium is used, the size of the printer device itself is formed large.
It is demanded that tandem-type color printer devices with an excellent shape can perform high-speed printing. In this type of printer device, image formation units of, for example, yellow (Y), magenta (M), cyan (C), and black (K) are used. Such image formation units are articles of consumption which are to be used up, thus need to be replaced with new ones periodically.
In the printer devices having the structure shown in
FIGS. 21 and 22
, the image formation unit is formed in the lower body
3
. If the structure is employed in a tandem-type color printer device, the image formation units of yellow (Y), magenta (M), cyan (C), black (K) are sequentially arranged in the lower body
3
. Hence, in the case of a maintenance operation, after the roof
2
is once opened, each of the image formation units needs to be taken out upward.
In the above-described conventional image formation device, even when only the first cartridge CT
1
(note: the first cartridge CT
1
lasts for a different time period from that of the second cartridge CT
2
) forming the image formation unit (cartridge CT), the cartridge CT (in the state where the cartridges CT
1
and CT
2
are incorporated together) is taken out from the printer device. The cartridge CT is divided into the cartridges CT
1
and CT
2
. Then, a new cartridge CT
1
is incorporated with the cartridge CT
2
, thereby forming a new cartridge CT. After this, the cartridge CT needs to be installed in the printer device.
Especially,
Hirosawa Shigeru
Kameyama Kazuhiro
Kurokawa Tetsushi
Nara Eiichi
Numazu Toshihiko
Casio Computer Co. Ltd.
Frishauf Holtz Goodman & Chick P.C.
Grainger Quana M.
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