Electrophotography – Machine operation – Job mode
Reexamination Certificate
2003-05-12
2004-09-14
Ngo, Hoang (Department: 2852)
Electrophotography
Machine operation
Job mode
C399S045000, C399S364000, C399S389000, C399S401000
Reexamination Certificate
active
06792224
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image forming apparatus and an image forming method for forming an image on one side or both sides of a sheet.
2. Description of Related Art
According to the conventional image forming apparatus disclosed in Japanese Patent Application Laid-Open No. 2001-125439, Japanese Patent Application Laid Open No. 11-157725 (1999) and the like, image data is generated by reading one side of an original, for example. The image forming apparatus then forms an image on one side of a sheet using the image data and discharges the sheet to a sheet receiving tray with said side down (face-down method).
FIG. 1
is a flowchart showing procedures of a user for forming an image with a conventional image forming apparatus
3
(see FIG.
3
A). A sheet having the same attribute at both sides, on each of which sides image can be formed, is held in a sheet holding tray in the image forming apparatus
3
. The image forming apparatus
3
forms an image on one side of the sheet when default image forming conditions (printing conditions) is used.
The user sets an original in an original retainer or an automatic original conveying unit provided in the image forming apparatus
3
(step S
1
). The user then determines whether an image is to be formed on both sides of the sheet (i.e., double-side printing is to be performed) or not (step S
2
). If the double-side printing is to be performed (YES at step S
2
), the user operates a double-side print key at an operation display provided in the image forming apparatus
3
(step S
3
). If an image is to be formed on one side of the sheet (i.e., single-side printing is to be performed) (NO at step S
2
), the user does not operate the double-side print key (the default printing conditions are used).
The user then determines whether a sheet having different attributes at respective sides (for example, a sheet having a letterhead on one side, an OHP sheet having one side on which printing is possible and the other side on which printing is not possible or the like, which is referred to as a special sheet hereinafter) is to be used or not (step S
4
). If the special sheet is to be used (YES at step S
4
), the user sets the special sheet in the sheet holding tray (step S
5
). At this time, the user sets the special sheet in the sheet holding tray with the front side up for performing single-side printing, or sets the special sheet in the sheet holding tray with the front side down for performing double-side printing.
If the special sheet is not to be used (NO at step S
4
), a sheet in a sheet holding tray is used.
Last of all, the user sets the printing conditions such as magnification or color strength of an image to be formed, the number of sheets or the like (step S
6
) and operates a printing key (step S
7
).
FIG. 2
is a flowchart showing processing procedures of image formation and sheet conveyance of the image forming apparatus
3
.
The image forming apparatus
3
determines whether the printing key has been operated or not (step S
11
). If the printing key has not been operated (NO at step S
11
), the image forming apparatus
3
waits until the printing key is operated. If the printing key has been operated (YES at step S
11
), the image forming apparatus
3
starts to read the original set in the original retainer or the automatic original conveying unit (step S
12
) and generates image data from the read image.
The image forming apparatus
3
then determines whether the sheet is to be reversed or not by determining whether the double-side print key had been operated or not before the printing key was operated (step S
13
). More specifically, if the double-side print key had been operated, the image forming apparatus
3
forms the image on one side of the sheet and then reverses the sheet to form an image on the other side. If the double-side print key had not been operated, the image forming apparatus
3
forms the image on one side of the sheet and discharges the sheet without reversing the sheet.
If the double-side print key had not been operated (NO at step S
13
), the image forming apparatus
3
performs single-side printing process. In the first place, the image forming apparatus
3
supplies a sheet from a sheet holding tray to a printer provided in the image forming apparatus
3
(step S
14
), forms an image on one side of the sheet using the image data (step S
15
) and discharges the sheet to the sheet receiving tray (step S
16
).
Last of all, the image forming apparatus
3
determines whether the next original is to be read or not (for example, whether there is an unread original in the automatic original conveying unit or not) (step S
17
). If the original is to be read (YES at step S
17
), the operation returns to step S
12
. If no original is to be read (NO at step S
17
), the operation returns to step S
11
.
If the double-side print key had been operated (YES at step S
13
), the image forming apparatus
3
performs the double-printing process. In the first place, the image forming apparatus
3
stores the image data in an image memory provided in the image forming apparatus
3
as first image data (step S
18
), starts to read the next original (step S
19
) and generates the second image data from the read image.
The image forming apparatus
3
then supplies a sheet from the sheet holding tray to the printer (step S
20
) and forms the second image on one side of the sheet using the second image data (step S
21
).
The image forming apparatus
3
then reverses the sheet (step S
22
), forms the first image on the other side of the sheet using the first image data read from the image memory (step S
23
) and discharges the sheet to the sheet receiving tray (step S
24
). The operation then returns to step S
17
.
FIGS. 3A through 4
are explanatory drawings showing procedures of image formation and sheet conveyance of the image forming apparatus
3
with which the single-side printing is performed.
The image forming apparatus
3
comprises a sheet holding tray
210
for holding one or a plurality of sheets P, and a feeder
211
for supplying one sheet after another held in the sheet holding tray
210
to a printer
20
. Each sheet P is held in the sheet holding tray
210
with one side PA (front side in case of the special sheet) of the sheet P up and the other side PB down.
The sheet P which has been supplied to the printer
20
from the sheet holding tray
210
by the feeder
211
is sequentially conveyed to the position between the photoconductor
200
and the imprinter
203
in the direction shown by an outline arrow such that the one side PA is in contact with the photoconductor
200
. When the sheet P is disposed between the photoconductor
200
and the imprinter
203
, an image is formed on the one side PA (referring to FIG.
3
A).
The sheet P passes through a fixer
23
and the image is fixed onto the one side PA of the sheet P. The sheet P is then conveyed in the direction shown by an outline arrow by the guide-in/guide-out roller
28
to the transit conveyance unit
18
(referring to
FIG. 3B
) and reaches the transit conveyance unit
18
with the one side PA down and the other side PB up (referring to FIG.
3
C). The sheet P is then discharged to the sheet receiving tray
56
by the guide-out roller
53
(referring to FIG.
4
).
In a case where a plurality of sheets P are discharged by the guide-out roller
53
, the sheets P are sequentially stacked in the sheet receiving tray
56
with the one side PA, on which an image is formed, facing down.
FIGS. 5A through 7C
are explanatory drawings showing procedures of image formation and sheet conveyance of the image forming apparatus
3
with which the double-side printing is performed. Each sheet P is held in the sheet holding tray
210
with one side PA (front side in case of special sheet) of the sheet P down and the other side PB up.
The sheet P which has been supplied to the printer
20
from the sheet holding tray
210
by the feeder
211
is sequentially conveyed to the position between the photoconductor
Fujii Shuhji
Imai Takashi
Ishikura Kaoru
Okamoto Yuji
Takahashi Kenji
Conlin David G.
Edwards & Angell LLP
Jensen Steven M.
Ngo Hoang
Sharp Kabushiki Kaisha
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