Facsimile and static presentation processing – Facsimile – Picture signal generator
Reexamination Certificate
1998-08-07
2001-05-15
Lee, Cheukfan (Department: 2722)
Facsimile and static presentation processing
Facsimile
Picture signal generator
C358S496000, C358S451000, C358S412000
Reexamination Certificate
active
06233068
ABSTRACT:
This application is based on application No. 9-215353 filed in Japan, the contents of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a digital copying system and an image reading apparatus, and more particularly to a digital copying system which reads an image of a document while feeding the document with an automatic document feeder, carries out digital processing toward the image data and reproduces the image on a sheet.
2. Description of Related Art
In the art of electrophotographic copying system, it is generally known as a document-feeding image reading method to read an image of a document with a scanner which is set at an image reading position while feeding the document over the image reading position. In such a copying system adopting the document-feeding image reading method, the speed of feeding a document is varied in accordance with the copying magnification so as to achieve the registered magnification in the sub scanning direction. The magnification in the main scanning direction is varied by varying the movement of the optical system of the scanner.
In the document-feeding image reading method, the speed of feeding a document is gained more to achieve a smaller copying magnification, and in such a case, a large load is applied to a document from the transport rollers. Especially when a thin paper document such as a slip, a duplicate or the like is fed, there is fear that the document may be damaged.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a digital copying system which inhibits the load on a document from the transport rollers so as not to damage the document.
In order to attain the object, a digital copying system according to the present invention comprises: an automatic document feeder for feeding a document set on a tray to a specified reading position; image reading means for reading an image of the document fed by the automatic document feeder at the reading position; image processing means for carrying out digital processing toward data read by the image reading means to produce print data; image forming means for forming an image on a sheet in accordance with the print data produced by the image processing means to reproduce the image of the document; magnification setting means for setting a copying magnification; and control means. The control means controls the automatic document feeder to operate in a first document feed mode to feed a document on the reading position at a speed to achieve the set copying magnification and in a second document feed mode to feed a document on the reading position at a speed different from the speed to achieve the set copying magnification.
In the first document feed mode, the automatic document feeder operates in the ordinary document-feeding image reading method. In this mode, the speed of feeding a document depends on the set copying magnification, and the smaller the copying magnification is, the higher the feed speed is. The second document feed mode is for a fragile thin paper document, and in this mode, it is possible to feed a document at a speed different from the speed to obtain the set copying magnification. Preferably, by lowering the feed speed, the load on the thin paper document applied from the transport rollers, etc. is lightened, and the document can be protected.
In the second document feed mode, because a document is fed for image reading at a speed different from the speed to obtain the set copying magnification, it is required to process the read data to have correct information on magnification so that the image of the document can be reproduced at the set copying magnification. Such processing can be carried out by the image processing means.
Also, in the second document feed mode, it is not always necessary to differ the feed speed, but it is sufficient to differ the feed speed only when the set copying magnification is such a value that a thin paper document must be fed at such a high speed to cause damage on the document. Specifically, when the set copying magnification is within a first range covering comparatively large magnifications, the feed speed is set to a value to obtain the copying magnification, and when the set copying magnification is within a second range covering comparatively small magnifications, the feed speed is set lower than the speed to obtain the set copying magnification. With this arrangement, it is avoided to lower the copying productivity unnecessarily.
Further, it is possible to provide inputting means which enables an operator to command execution of the second document feed mode. Also, it is possible to provide detecting means for detecting whether a document is thin paper or not so that operation in the second document feed mode can be automatically executed when the document is judged to be thin paper. Moreover, the automatic document feeder may be so structured as to operate in a mode in which every time a document is set on a tray, the automatic document feeder automatically feeds the document to the reading position, and execution of the second document feed mode may be associated with this mode.
REFERENCES:
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patent: 4579327 (1986-04-01), Furuichi et al.
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patent: 5257064 (1993-10-01), Okamoto et al.
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Lee Cheukfan
Minolta Co. , Ltd.
Morrison & Foerster / LLP
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