Electrophotography – Image formation – Photoconductive member
Reexamination Certificate
2003-04-03
2004-10-26
Brase, Sandra L. (Department: 2852)
Electrophotography
Image formation
Photoconductive member
C399S401000, C399S405000
Reexamination Certificate
active
06810224
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of Korean Patent Application No. 2002-34974, filed Jun. 21, 2002, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an office machine, such as a laser printer, photocopier, or the like, and more particularly, to driving apparatus and method in a double-side printable office machine which can reduce a waste toner amount and a volume of a developing unit, decrease wear and tear and noise of the developing unit, and prevent unnecessary driving of the developing unit during fixing, discharging and, in particular, returning a sheet of paper by driving, fixing, discharging, and returning operations for double-side printings separately from paper pickup/supply and developing operations.
2. Description of the Related Art
In general, as shown in
FIG. 1
, a double-side printable office machine, such as a double-side printing laser printer
1
, includes a paper-supplying cassette
11
detachably mounted to a frame
10
of a main body of the double-side printable laser printer
1
, a pickup/transport unit
6
picking up and transporting a sheet of paper P loaded in the paper-supplying cassette
11
, a developing unit
30
forming a toner image on the sheet P, a fixing unit
40
heat-pressing the toner image formed on the sheet P to fix the toner image as a visible toner image, a paper discharge unit
50
discharging the sheet P on which the visible toner image is fixed by the fixing unit
40
, and a double-side printing unit
80
re-feeding a one-side printed sheet P through the fixing unit
40
to the developing unit
30
to print the other side of the sheet P.
The paper-supplying cassette
11
is installed in a lower side of the frame
10
of the main body and supports the sheet P through a paper-pressing plate
13
supported by an elastic spring
12
so that the sheets P elastically ascend and descend.
Over the paper-supplying cassette
11
is installed the pickup/transport unit
6
sequentially picking up and transporting the sheets P loaded in the paper-supplying cassette
11
one by one. The pickup/transport unit
6
has a first paper sensor (not shown) sensing whether the sheets P are loaded in the paper-supplying cassette
11
, a first pickup roller
7
picking up the sheets P loaded in the paper-supplying cassette
11
, and a transport roller
23
and reverse roller
24
transporting the picked-up sheet P to the developing unit
30
along a paper transport guide
22
forming a paper transport path A.
In order to manually supply the sheet P, the pickup/transport unit
6
includes a manual paper-supplying cassette
27
mounted to protrude toward a front of the main body, a second paper sensor (not shown) sensing whether the sheet P is loaded in the manual paper-supplying cassette
27
, and a second pickup roller
25
picking up the sheet P loaded in the manual paper-supplying cassette
27
and transporting the sheet P toward a register roller
28
and a back-up roller
29
. As described above, the manual paper-supplying cassette
27
, the second paper sensor, and the second pickup roller
25
constitute a manual feeder.
The developing unit
30
is detachably installed on the frame
10
of the main body, is disposed over the pickup/transport unit
6
, and includes a photosensitive drum
32
forming an electrostatic latent image by a laser beam emitted from a laser scanning unit (LSU)
76
based on an image signal, a charging roller
49
charging the photosensitive drum
32
, a developing roller
47
developing the electrostatic latent image formed on the photosensitive drum
32
with toner to form the toner image, a cleaning blade
48
cleaning a toner waste remaining on a surface of the photosensitive drum
32
after the toner image is transferred to the sheet P, and a waste toner bin
46
storing the toner waste.
Under the photosensitive drum
32
of the developing unit
30
is installed a transfer roller
66
transferring the toner image formed on the photosensitive drum
32
to the sheet P.
The fixing unit
40
pressing and fixing the toner image has a fixing roller
41
and a fixing backup roller
42
.
The paper discharge unit
50
has first, second, and third paper discharge rollers
51
,
55
, and
60
and backup rollers
52
,
63
,
64
, and
65
disposed along the paper transport guide
22
downstream in a paper transport direction of the fixing unit
40
, and discharges the sheet P on which the toner image is fixed by the fixing unit
40
, to an external paper discharge cassette
67
.
The double-side printing unit
80
includes a paper reverse-transport guide
62
constituting a paper return path B for re-feeding a one-side printed sheet P to the developing unit
30
to print another toner image on a reverse side of the sheet P, a paper transport direction switching guide
54
directing a paper transportation so that the sheet P is transported to the paper return path B upon the double-side printing, and first and second reverse-transport rollers
70
and
90
transporting the sheet P through the paper transport path B.
The paper transport direction switching guide
54
is disposed at a position which the paper return path B comes across the paper transport path A, and is disposed upstream in the paper transport path A of the third paper discharge roller
60
of the discharge unit
50
, thereby directing the sheet P to the paper return path B for the double-side printing.
In a double-side printing process of the laser printer
1
constructed as above, first, the sheet P loaded in the paper-supplying cassette
11
or in the manual paper-supplying cassette
27
is picked up by the corresponding first and second pickup rollers
7
and
25
based on an operation or a non-operation of the second paper sensor to automatically or manually feed the sheet P, and conveyed to the developing unit
30
through the register roller
28
along the paper transport guide
22
.
While the sheet P is being conveyed to the developing unit
30
, the electrostatic latent image is formed on the photosensitive drum
32
of the developing unit
30
by the laser beam emitted from the LSU
76
according to the image signal, and the toner is attracted to the electrostatic latent image developed on the photosensitive drum
32
by the developing roller
47
so that the electrostatic latent image is developed to the toner image in a visible form.
The toner image formed on the photosensitive drum
32
is transferred, when the sheet P is transported to the developing unit
30
along the paper transport guide
22
, on one side of the sheet P, that is, on an upper side of the sheet P by the transfer roller
66
, and the toner image transferred on the upper side of the sheet P is fixed on the upper side of the sheet P by the fixing roller
41
and the fixing backup roller
42
which constitute the fixing unit
40
.
After the toner image is transferred on the upper side of the sheet P from the photosensitive drum
32
, the toner waste remaining on the surface of the photosensitive drum
32
according to a transfer efficiency is removed by the cleaning blade
48
and stored in the waste toner bin
46
located below the cleaning blade
48
.
The sheet P passing through the fixing roller
41
and the fixing backup roller
42
progresses into the third paper discharge roller
60
by the first and second paper discharge roller
51
and
55
. At this time, the sheet P pushes a third paper sensor
44
located downstream in the paper transport direction of the fixing roller
41
, and, accordingly, the third paper sensor
44
senses a passage of the sheet P.
At this time, when the printer
1
, performs a one-side printing mode, the sheet P is discharged to the paper discharge cassette
67
through the third paper discharge roller
60
.
However, when the printer
1
carries out a double-side printing mode, the third paper discharge roller
60
is driven to be reversely rotated by a controller as a certain
LandOfFree
Driving apparatus and method for a double-side printable... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Driving apparatus and method for a double-side printable..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Driving apparatus and method for a double-side printable... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3332823