Electrophotography – Document handling – Copy
Reexamination Certificate
1999-11-29
2001-02-06
Moses, Richard (Department: 2852)
Electrophotography
Document handling
Copy
C399S364000, C399S391000
Reexamination Certificate
active
06185406
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to an image forming apparatus in which images are formed selectively on one side or both sides of recording media based on the input image data.
(2) Description of the Related Art
A typical image forming apparatus for forming image on both sides of recording media has an intermediate tray which temporarily stores the recording media with an image on the first side thereon and is arranged in the recording media conveyance path extending from the paper feed potion to the paper output portion passing through the imaging portion. The recording media stored in the intermediate tray is inverted so as to be upside down and conveyed to the imaging portion so as to form an image on the second side. In such an image forming apparatus, recording media of which images are to be printed only on one side will be discharged to the paper output portion after passing through the imaging portion without being held in the intermediate tray.
In this way, the recording media of which images are to be printed on only one side is conveyed through the different path from that of the recording media of which images are to be printed on both sides. Therefore, in the image forming apparatus in which images can be formed selectively on one side or both sides of recording media based on the input image data, the conveyance path of the recording media needs to be switched selectively.
Accordingly, the conventional image forming apparatus is configured so that mode selection as to whether images are to be formed on one side or both sides of the recording media is designated before the start of image forming for a single medium or multiple recording media and then based on the selected mode a recording media conveyance path is selected. Therefore, in the conventional image forming apparatus, once an image forming operation is started, the recording media will be conveyed along the conveyance path designated based on the mode selected before the start of operation unless the operation is interrupted and the mode selection is changed.
Thus, in the conventional image forming apparatus, the designated mode at the start of operation, whichever it is, the duplex print mode or one-sided print mode, will be maintained during the image forming operation once it has been started. Therefore, if the image data to be supplied during an image forming operation started in the duplex print mode includes both the image data for forming images on both sides of the recording media and the image data for forming images on only one side of the recording media, the recording media of which images are to be formed only one side will also be conveyed along the same conveyance path as that of the recording media of which images are to be formed on both sides. Therefore, the recording media of which images are to be formed on only one side are compelled to be held in the intermediate tray and turned upside down, unnecessarily, causing a time loss and degradation of operational efficiency.
For example, referring to
FIG. 1
, in an image forming operation in the duplex print mode for image data of two sheets including image data G
1
and G
2
to be formed on both sides of the first recording medium P
1
and image data G
3
to be formed on one side of the second recording medium P
2
, the first recording medium P
1
is fed from a paper feed portion
91
in a copier
90
and is formed on its first side with an image of image data G
1
via an imaging portion
92
, and then is stored in an intermediate tray
93
. Whilst this first recording medium P
1
is conveyed from intermediate tray
93
toward imaging portion
92
with its face upside down and is formed on its second side with an image of image data G
2
, the second recording medium P
2
is fed from paper feed portion
91
. After discharge of recording medium P
1
to a paper output tray
94
, an image of image data G
3
is formed on the first side of recording medium P
2
via imaging portion
92
. The recording medium P
2
of which the image of image data G
3
has been formed on the first side is also held in intermediate tray
93
and fed again to imaging portion
92
. However, no image data to be formed is present in imaging portion
92
, so that the recording medium P
2
is discharged to paper output tray
94
with no image formed on its second side. Thus the image forming operation is completed.
In this way, in conventional image forming apparatus
90
, if the image data to be input during the image forming operation in the duplex printing mode includes image data G
3
for forming an image on only one side of a recording medium, recording medium P
2
on which the image of this image data G
3
is formed is forced, wastefully, to be conveyed to paper output tray
94
by way of intermediate tray
93
and imaging portion
92
despite the fact that no image is formed through the second passage of imaging portion
92
.
As a technique to eliminate the time loss during an image forming operation in the duplex printing mode, Japanese Patent Application Laid-Open Hei No.5-323720 discloses a configuration wherein when a recording medium different in size from that held in the intermediate tray is conveyed to the intermediate tray, the image formation for the second side of the recording medium being held in the intermediate tray is performed in preference and then the position of the aligning means of the intermediate tray is controlled and switched. However this publication has no reference to eliminating the time loss arising when the image data input during the image forming operation started in the duplex printing mode includes both the image data for forming images on both sides of recording media and the image data for forming images on only one side of recording media.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an image forming apparatus wherein selection of conveyance paths of each recording medium is performed based on the judgment of whether input image data is one for forming images on both sides of the recording medium or one for forming an image on one side thereof so as to positively eliminate the time loss arising when recording media of which images are to be formed on one side, are conveyed along the same path as recording media of which images are to be formed on both sides if the input image data includes both image data to be formed on both sides of the recording media and image data to be formed on only one side of the recording media, thus making it possible to improve the operational efficiency.
In order to achieve the above object, the present invention is configured as follows:
In accordance with the first aspect of the invention, an image forming apparatus includes: a determining process for determining whether the image data to be imaged is one for a recording medium of which images are formed on both sides or one for a recording medium of which an image is formed on only one side; and a conveyance path switching process for switching the conveyance path of the recording medium based on a determination result.
In accordance with the second aspect of the invention, the image forming apparatus having the above first aspect is characterized in that the conveyance path switching process switches the conveyance path between a first conveyance path for conveying a recording medium, on which an image has been formed on one side via a imaging portion, to a paper output portion by way of a storage portion and the imaging portion and a second conveyance path for directly conveying a recording medium, on which an image has been formed on one side via the imaging portion, to the paper output portion.
In accordance with the third aspect of the invention, the image forming apparatus having the above first or second aspect is characterized in that the conveyance path switching process further comprises a conveyance order determining process for determining the order of conveyance of the recording media passing through a plurality of conveyance paths, b
Moses Richard
Sharp Kabushiki Kaisha
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