Sheet feeding or delivering – Feeding – By means to convey sheet
Reexamination Certificate
1998-12-22
2001-01-30
Bollinger, David H. (Department: 3651)
Sheet feeding or delivering
Feeding
By means to convey sheet
Reexamination Certificate
active
06179289
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a paper-feed control unit and the method of control for an image-forming apparatus. In particular, when forming an image on printing paper the feeding of a sheet of printing paper is performed by a resist roller and a paper-ejection-roller of an image-forming apparatus controlled by a paper-feed control unit.
BACKGROUND OF THE INVENTION
In a serial printing apparatus such as, for example, a dot printer, an ink-jet printer or the like, an image is formed on a sheet of printing paper by printing an image having a predetermined width a plurality of times on the paper. Therefore, the feeding of paper at intervals corresponding to the predetermined width should be performed with relative precision.
FIG. 6
is a block diagram showing a paper-feed control unit of a conventional image-forming apparatus.
FIGS. 4A through 4D
illustrate the operation of a paper-feed control unit of an orthogonal-transfer-type image-forming apparatus disclosed in the Japanese Patent Application Laid Open No. H09-230715, in which a toner image is transferred in an orthogonal direction to the paper feeding direction.
In
FIG. 6
, a printing controller
2
controls a transfer controller
3
for controlling image transfer, and a paper-feed-motor-drive-controller
4
. The paper-feed-motor-drive-controller
4
controls the drive of a paper-feed-motor
5
. The paper-feed-motor
5
causes resist roller
6
and paper-ejection-roller
7
to rotate. The components shown in
FIG. 6
, with the exception of transfer controller
3
, comprise the paper-feed control unit.
In
FIG. 4A
, resist roller
6
is disposed upstream of toner image carrier
100
(the paper feeding direction shown by arrow
20
) and paper-ejection-roller
7
is disposed downstream of toner image carrier
100
. In toner image carrier
100
, a toner image is formed corresponding to inputted image data. Transfer-facing-roller
8
performs printing by transferring a toner image, formed in the toner image carrier
100
, to a sheet of printing paper
12
by rotating and moving in a direction orthogonal to paper feeding direction
20
. As shown in
FIG. 2A
, printing area P is an area between right end
100
a
(end at downstream side of paper feeding direction) and left end
100
b
(end of upstream side of toner image carrier
100
) of toner image carrier
100
. A transfer plate
9
is pressed by transfer-facing-roller
8
through toner image carrier
100
and printing paper
12
. Resist-pinch-roller
10
faces resist roller
6
. An explanation of the structure and operation of a chassis supporting transfer plate
9
, etc. is omitted. In
FIG. 4D
, LP represents the length of printing paper
12
in paper feeding direction
20
,
12
a
represents the front end of printing paper
12
of the downstream side of paper feeding direction
20
,
12
b
represents the back end (final end) of the upstream side of paper feeding direction
20
, and “A” represents the dimension from resist roller
6
to left end
100
b
of toner carrier
100
as shown in FIG.
4
A.
FIG. 5
is a flow chart showing an operation of a paper-feed control unit of a conventional image-forming apparatus. The operation is described below referring to FIG.
4
A through
FIG. 4D
,
FIG. 5
, and FIG.
6
.
First, paper-feed-motor-drive-controller
4
rotates paper-feed-motor
5
by an A-step (S
21
). For paper-feed-motor
5
, a stepping motor may be used. Following an A-step rotation of paper-feed-motor
5
, front end
12
a
of the printing paper reaches to substantially the same position as that of right end
100
a
of printing area P of toner image carrier
100
. Then, a first transfer is performed (S
22
) on first printing area P.
Next, paper-feed-motor
5
rotates by a B-step (S
23
) feeding printing paper
12
by paper-feed-dimension B
1
. Dimension B
1
is equal to the width of first printing area P as shown in FIG.
4
B. FIG.
4
B through
FIG. 4D
show the relative movement from the position in
FIG. 4A
of printing paper
12
. In step S
24
, a second transfer is performed on second printing area P.
Then, paper-feed-motor
5
rotates again by a B-step (S
25
) for feeding printing paper
12
by a paper-feed-dimension B
1
. In step S
26
, a third transfer is performed on third printing area P.
Further, paper-feed-motor
5
rotates by B-step (S
27
) for feeding printing paper
12
by a paper-feed-dimension B
1
, and as shown in
FIG. 4D
, a fourth transfer is performed (S
28
) on forth printing area W (final printing area). After final printing, the printing paper is ejected (S
29
).
As shown in
FIG. 4D
, in the paper-feed control unit of the above conventional image-forming apparatus, because the paper-feed-dimension after the third printing is B
1
, back end
12
b
of printing paper
12
arrives at a position displaced by a dimension LL from resist roller
6
. In
FIG. 4
, LL>A, and a paper-feed of dimension LL is performed by paper-ejection-roller
7
. Due to the dispersion of the diameter of the roller of paper-ejection-roller
7
, however, the paper-feed-dimension may not be accurately B
1
, and may differ from the paper-feed dimension traversed by resist roller
6
, by which the quality of the transferred image may deteriorate. Therefore, it is desirable to make the dimension of paper-feed traversed by a paper-ejection-roller as short as possible.
SUMMARY OF THE INVENTION
The present invention aims to provide a paper-feed control unit and a method of controlling an image-forming apparatus which may result in an improvement to the quality of a transferred image.
A controlled image-forming apparatus in accordance with the present invention includes: a resist roller, for feeding a sheet of printing paper; a paper-ejection-roller disposed at the downstream side of the resist roller in the paper feeding direction; an image-forming unit, disposed between the resist roller and the paper-ejection-roller for forming an image of predetermined width; a motor for rotating the resist roller and the paper-ejection-roller; and a motor-drive-controller for controlling said motor. The motor is controlled to feed printing paper of a dimension narrower than the predetermined width when the dimension of the upstream-side-printing-paper-area, on which image-forming has not yet been performed by the image-forming unit, becomes narrower than the predetermined width. The motor is also controlled to perform paper-feed of the predetermined width a plurality of times, and at least one paper-feed of a width narrower than the predetermined width. The image-forming unit performs image-forming on the printing paper.
By the above control, the dimension between the back end of the printing paper and the resist roller may be shortened. Hence, the paper-feed may be performed precisely, by which the quality of the transferred image may be improved.
REFERENCES:
patent: 6017160 (2000-01-01), Sato et al.
patent: 9-230715 (1997-09-01), None
Adachi Tetsuya
Goto Masanori
Hara Yukinori
Matsushita Yusuke
Matsuzoe Hisanobu
Bollinger David H.
Matsushita Electric - Industrial Co., Ltd.
Ratner & Prestia
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