Photocopying – Using microcapsules – Sheet feeding
Reexamination Certificate
1999-09-09
2001-05-22
Adams, Russell (Department: 2851)
Photocopying
Using microcapsules
Sheet feeding
C399S019000, C399S021000, C271S003060, C271S003130
Reexamination Certificate
active
06236450
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus for successively feeding sheet-like objects by means of an automatic document feeder and copying the image information regarding images formed on the objects.
A copying apparatus that utilizes an electrostatic copying process is an example of an image forming apparatus. In the copying apparatus, an image on a document to be copied is represented in the form of image information that indicate the light and shade portions of the image. An electrostatic latent image is formed on a photosensitive body in accordance with the image information, and the electrostatic latent image is then visualized with toner (i.e., a developer), thus making a copy of the document.
A developer image, i.e., the visualized latent image, is output to recording mediums, such as sheets of paper.
An automatic document feeder, which successively feeds sheet-like objects to an image formation section one by one, is in widespread use since the use of such a feeder helps lighten the load that is imposed on the user at the time of a copying operation.
In the case where copies are made, with original documents being successively fed by an automatic document feeder, a document feed error (a paper jam or a document jam) may occur in the feeding mechanism of the automatic document feeder. In this happens, several of the original documents, which are being fed then, will stop and stay at different positions inside the automatic document feeder.
If, due to the document jam, a number of original documents stay at different positions inside the document feeder, the user has to determine which document should be returned to the automatic document feeder. To be more specific, the user has to compare the images on the copies discharged and stacked on a discharge section of the copying apparatus with those images which are shown on the documents which are being fed or have not yet been fed at the time of the document jam. By this comparison, the user discriminates between documents from which image information have already been copied and documents from which image information have not yet been copied. After re-setting the documents that have to be returned to the automatic document feeder, the copying operation is resumed.
If the original documents are sheets which bears images on both sides, or if the copies produced by the copying operation are sheets which bear images on both sides, the operation for identifying documents that should be returned to the automatic document feeder, requires much time, and the time needed for the copying operation is inevitably long.
It is likely that the documents from which copies have already been made will be erroneously subjected to the copying operation once again, resulting in extra copies. It is also likely that the documents which should be subjected to the copying operation will be overlooked, resulting in failure to make copies of all documents. If copies to be made bear images on both sides, documents that should be re-set must be determined without an error. If an error is made in this determination, the pages of the images on the copies will be numbered erroneously. The copies having such erroneous page numbering may be useless.
BRIEF SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide an image forming apparatus which performs a successive copying operation using an automatic document feeder and which can resume the successive copying operation with high efficiency even after the occurrence of a document feed stop (document jam).
To achieve this object, the present invention provides an image forming apparatus provided with an automatic document feeder and comprising:
a document table for holding a document;
an image forming section for making a copy of the document by performing an image forming operation, the image forming operation including forming an electrostatic image corresponding to image light which is obtained by radiating light onto the document held on the document table, and supplying a visualizing agent to the electrostatic image;
a document feeding/discharging device for feeding a document to the document table, stopping the document when the document comes to a predetermined position on the document table, and discharging the document to a position away from an image information reading area after image information are read from the document located there so as to permit the image forming section to execute the image forming operation;
a feed state monitoring device for monitoring how the document is fed or discharged by the document feeding/discharging device; and
a control device for detecting a state where a document fed by the document feeding/discharging device is jammed in a feeder section of the document feeding/discharging device, determining those documents from which image information are not read, on the basis of monitor results output from the feed state monitoring device, and resuming the image forming operation only for the documents from which the image information are not read.
The present invention also provides an image forming apparatus comprising:
a document table for holding a document;
an image forming section for making a copy of the document by performing an image forming operation, the image forming operation including forming an electrostatic image corresponding to image light which is obtained by radiating light onto the document held on the document table, and supplying a visualizing agent to the electrostatic image;
a document feeding device including a document holder section for holding a preset number of sheetlike documents, and a feeder mechanism, the feeder mechanism feeding documents from the documents holder section to the document table one by one, stopping each of the documents when the document comes to a predetermined position on the document table, and discharging the documents to a predetermined position when images on the documents have been read for the image forming operation;
a plurality of sensors for locating where in the feeder mechanism a document is jammed during a feeding operation;
a display device, operating when the document is jammed in the feeder mechanism, for indicating that all documents should be set in the document holder section once again, including documents from which image information are read for image formation, the document jammed in the feeder mechanism, and documents remaining in the document holder section; and
a feed control device for controlling a document feed operation on the basis of a position which is detected by the sensors and at which the document is jammed in the feeder mechanism, the document feed operation being controlled such that the documents from which the image information are read are fed to the predetermined position without being stopped on the document table, and the documents from which the image information are not read and subsequently-fed documents are temporarily stopped at a predetermined position on the document table and are discharged to the predetermined position after document images are read therefrom for the image forming operation.
The present invention further provides an image forming apparatus comprising:
a document feeding device for feeding a plurality of documents to a predetermined position on a document table one by one and for discharging the documents from the document table to a predetermined discharge position at predetermined timings;
a first sensor for checking whether or not a document fed by the document feeding device reaches the predetermined position on the document table;
a second sensor for checking whether or not a document discharged from the document table by the document feeding device reaches the predetermined discharge position;
a counter device for checking the number of documents fed to the predetermined position on the document table by the document feeding device, on the basis of results of checking obtained by the first and second sensors; and
display means for displaying an operating condition, a
Adams Russell
Brown Khaled
Foley & Lardner
Toshiba Tec Kabushiki Kaisha
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