Electrophotography – Document handling – Original
Reexamination Certificate
1999-03-03
2001-01-30
Braun, Fred L. (Department: 2852)
Electrophotography
Document handling
Original
C271S004030, C271S004080
Reexamination Certificate
active
06181906
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image forming apparatus having an original conveying apparatus, and, more particularly, it relates to an image forming apparatus having an original conveying apparatus, in which, for example, if a recording sheet is jammed in a main body of the image forming apparatus, non-processed originals conveyed by the original conveying apparatus can easily be re-set.
2. Related Background Art
In the past, in image forming apparatuses such as electrophotographic copying machines, an auto original conveying apparatus (an auto document feeder (ADF)) capable of automatically separating and conveying originals (documents) and setting the original on an original support glass at a predetermined position thereon has widely been used. Since the original can be set without opening and closing a pressure plate of the image forming apparatus, the ADF is presently inevitable for office copying machines in a view point of efficiency of a copying operation.
First of all, an electrophotographic copying machine as an image forming apparatus to which the present invention is concerned will be described.
FIG. 4
is an elevational sectional view of an electrophotographic copying machine to which the present invention is concerned. An original conveying apparatus
50
capable of automatically supplying a plurality of originals is rested on an original support glass plate
1
of a main body
40
of the copying machine.
In
FIG. 4
, a sheet bundle
15
rested in a cassette
13
is urged against a sheet supply roller (recording sheet supply portion)
16
by means of an intermediate plate
14
, so that an uppermost sheet in the sheet bundle is separated by the sheet supply roller
16
and a separation member and the separated sheet is conveyed to a pair of regist rollers
18
, where registration of the sheet
15
in a longitudinal direction is adjusted. The original rested on the original support glass plate
1
in a manner described later is illuminated by an illumination lamp
4
, and a read image is incident on a photosensitive drum as an electrophotographic photosensitive body (image forming means)
19
through a mirror
3
and a lens
25
, thereby forming an electrostatic latent image. The electrostatic latent image is converted into a toner image by a developing device
21
using toner as developing agent. Positions of the toner image and the recording sheet
15
are in a timed relation obtained by the pair of regist rollers
18
, and the toner image is transferred onto the sheet
15
at a proper position thereon by means of a transfer roller (transfer means)
20
. After the transferring, the sheet
15
is sent, by a convey means
26
, to a fixing device
27
, where the toner image is heated and fused to be fixed to the sheet
15
. Thereafter, the sheet is discharged onto a sheet discharge tray
33
by a pair of discharge rollers
28
.
Next, an operation of the ADF (original conveying apparatus)
50
will be briefly described.
As shown in
FIG. 4
, the originals are rested on an original tray (original resting means)
5
by the operator. In case of the ADF
50
, the originals are successively rested on the original tray
5
with imaged surfaces facing downwardly. The first original is nearest the original tray
5
. When a lever
29
of an original presence/absence detection sensor is laid laterally by leading ends (tip ends) of the originals, a photo-interrupter (not shown) is blocked, with the result that an original presence signal is sent to a controller as a control device (control means)
60
.
In this condition, when a copy button (not shown) is depressed, an intermediate plate
30
is operated by a drive device (not shown) to contact the leading ends of the originals with a supply roller
7
. In this condition, when the supply roller
7
is rotated, an uppermost original in the original stack rested on the intermediate plate (and next and/or other original sheet, in some cases) are conveyed to enter into a nip between a separation pad
8
and the supply roller
7
. The original supply roller
7
and the separation pad
8
constitute an original supply means.
In this case, the originals other than the uppermost original are stopped by the separation pad
8
, with the result that only one original is conveyed to a pair of registration rollers
9
a
,
9
b
. The pair of registration rollers
9
a
,
9
b
serve to correct skew-feed of the original and to effect registration adjustment. Thereafter, the original is conveyed onto the original support glass plate
1
by an original convey belt
10
. When the leading end of the original has passed through a predetermined position on the original support glass plate
1
and reaches an original reverse sensor
31
, the original is stopped temporarily, and then is returned by a predetermined amount and then is stopped. This operation is effected, so that, when the original is scanned, the original is correctly positioned on the original support glass plate
1
. At this predetermined position, after the original is scanned by an illumination lamp
4
(scan means) such as a halogen lamp mounted on a mirror support (not shown), the original convey belt
10
is operated again to discharge the original onto a discharge tray
32
. When a plurality of originals are processed, a subsequent original is supplied while a preceding original is being discharged, and the similar procedures are repeated.
In such an ADF
50
, it is assumed that the operator wishes to obtain five sets of copies from three originals by setting the copy number to “5” in an operation portion (not shown).
The operator rests three originals on the original tray
5
of the ADF
50
and depresses a copy start button. As a result, first of all, an uppermost original in the original stack, i.e., a last page (third page) original with imaged surface facing downwardly is urged against the original supply roller
7
by the intermediate plate
30
. Then, the original is supplied by the rotation of the original supply roller
7
and then is set at the predetermined position on the original support glass plate
1
by the convey belt
10
.
In the present ADF
50
, before the optical scanning for the original is started, the subsequent original starts to be supplied, and the subsequent original is waiting while forming a loop therein in front of the pair of registration rollers
9
a
,
9
b
. In this condition, the original on the original support glass plate
1
is scanned. The scanning is effected by five times in total for five recording sheets. After the last fifth scanning is finished, when the illumination lamp
4
(including the first mirror support) starts to be shifted in the opposite direction, the original on the original support glass plate
1
is conveyed toward the discharge tray
32
by the rotation of the convey belt
10
. At the same time, the subsequent original having the loop and waited at the pair of registration rollers
9
a
,
9
b
is conveyed by the rotation of the paired registration rollers
9
a
,
9
b
and is reached to the predetermined position on the original support glass plate by the convey belt
10
conveying the preceding original.
The reason for effecting the discharging of the preceding original and the supplying of the subsequent original simultaneously in this way is that the illumination lamp
4
for scanning the original is prevented from being stopped useless at the home position by quickly exchanging the originals. If it takes a long time for exchanging the originals, even when a copying speed of the copying machine (image forming apparatus)
40
is sufficiently high, due to the long exchanging time, the inherent copying speed cannot be utilized completely. It is assumed that the original rested on the original support glass plate
1
is copied continuously. In this case, when the ADF
50
is incorporated into a machine capable of obtaining twelve copies per a minute, if twelve copies can be obtained for each minute, it is said that the copying efficiency is good. However, if an AD
Braun Fred L.
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
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