Automatic document feeders for copying machines and method for automatically controlling such

An automatic document feeder for a copying machine comprising:

• a. document feeding base means for permitting a plurality of documents to be copied to be consecutively set thereon;
• b. drive power source means for providing forward and reversed directional drive power useful for document feeding, document conveying and document recovering operations of said document feeder;
• c. document feeding means for separating and feeding one by one the documents set on said document feeding base means using the forward directional drive power transmitted from said drive power source means, said document feeding means being applied with only the forward directional drive power by means of an one way clutch and being selectively operated using a part of the forward directional drive power which is selectively transmitted thereto by means of a clutch gear;
• d. document conveying means for conveying using the forward directional drive power the document in the forward direction and exactly setting using the reversed directional drive power the document on a predetermined reference copying position of the copying machine, said document conveying means being directly applied with the forward and reversed directional drive power from the drive power source means;
• document recovering means for recovering using the forward directional drive power of the drive power source means the document after a copying operation;
• and
• e. recovered document base means for permitting a plurality of recovered documents to be consecutively piled up thereon, said recovered document base means being formed as disposed below the document feeding base means and being lower than a document ejection position of said document recovering means, thereby causing the recovered documents to be neatly piled up thereon;
• f. wherein said document feeding means comprises:
• (1) said one way clutch for transmitting only the forward directional drive power of the drive power source means to the document feeding means;
• (2) an idle gear engaging with the one way clutch gear;
• (3) an electronic clutch gear engaging with said idle gear, said electronic clutch gear receiving the forward directional drive power from the one way clutch gear by way of the idle gear;
• (4) an electronic clutch for selectively driving using a part of the forward directional drive power a document separating roller drive shaft as required, the electronic clutch being applied with the forward directional drive power of the drive power source means from said electronic clutch gear;
• (5) a register roller drive gear for transmitting the forward directional drive power of the drive power source means to a register roller drive shaft, said register roller drive gear engaging with the electronic clutch gear and being applied with the forward directional drive power of the drive power source means from the electronic clutch gear;
• (6) a document separating roller for separating and feeding the document to be copied, said document separating roller being mounted on said document separating roller drive shaft, thereby being rotated only when the electronic clutch is activated in order to transmit the forward directional drive power of the drive power source means to the document separating roller drive shaft;
• (7) at least one register roller for introducing the fed document to said document conveying means, said register roller being mounted on said register roller drive shaft, thereby continuously rotating during a forward directional rotation of the drive power source means;
• (8) at least one register driven roller engaging with the register roller, said register driven roller being mounted on the document separating roller drive shaft, having a larger inner diameter than an outer diameter of the document separating roller drive shaft and being installed on the document separating roller drive shaft such that it is raced with respect to the document separating roller drive shaft during its rotation together with the register roller;
• (9) a pick-up roller for picking up the document to be copied set on the document feeding base means, said pick-up roller being driven by the drive power transmitted from the drive power source means by way of the document separating roller and having a semicircular shape provided with a document contact plane surface;
• (10) a document sensor for detecting whether the document to be copied is set on the document feeding base means;
• and
• (11) document size sensing means for sensing a size of the document to be copied.

A method for automatically controlling an automatic document feeder for a copying machine, which document feeder comprises a central control unit to which an interface, a motor drive unit, an electronic clutch, a display, a document sensor, document size sensing means and pick-up roller state sensing means are coupled, the method comprising the steps of:

• (a) determining, upon checking a signal having been outputted from said document sensor, whether a document to be copied is set on a document feeding base;
• (b) if no document to be copied is set on said document feeding base, determining, upon checking a signal having been outputted from said pick-up roller state sensing means, whether said semicircular pick-up roller has been in a stand-by state, if the semicircular pick-up roller has not been in the stand-by state, driving said electronic clutch as well as said motor drive unit so as to cause the semicircular pick-up roller to achieve the stand-by state, thereafter, returning to step (a) and waiting for a document which is to be newly set on the document feeding base;
• (c) if a document to be copied is set on the document feeding base, determining, upon checking all of a plurality of operational states of the document feeder, whether there has occurred an abnormal operational state in the document feeder, thereafter, if there has occurred in abnormal operational state, displaying an occurrence of the abnormal operational state by means of said display and waiting for removal of the abnormal operational state;
• (d) if there has occurred no abnormal operational state in the document feeder, waiting for a copying start signal which is to be applied from a copying machine control circuit to said central control unit;
• (e) upon receiving the copying start signal having been outputted from said copying machine control circuit, determining whether a document feeding start signal has been inputted,
• (f) if the document feeding start signal has been inputted, driving the electronic clutch, which causes the drive power of drive power source means to be selectively transmitted to a document separating roller drive shaft, for a predetermined time, thereby separating and feeding the document to be copied;
• (g) conveying in the forward direction the document to be copied to a copying position simultaneously with sensing a size of the conveyed document and moving in the reversed direction the document to cause the document to be exactly set on a predetermined reference copying position of a contact glass of the copying machine;
• (h) outputting a document setting end signal to the copying machine control circuit to cause a copying operation to be carried out by the copying machine and waiting for a document recovering start signal which is to be outputted from the copying machine control circuit;
• (i) upon receiving the document setting end signal having been outputted from the copying machine control circuit, determining whether another document to be copied is set on the document feeding base;
• and
• (j) if there is another document to be copied on the document feeding base, carrying out only a document recovering operation for the copied document in accordance with a time when only the document recovering operation for the copied document is carried out and another time when the document recovering operation for the copied document and a document feeding operation for a new document are carried out at the same, each time being determined in consideration of a length of the new document, then returning to the step (e) so as to repeatedly perform the above steps (e) to (j), thereafter, if there is no document to be copied on the document feeding base, carrying out only a document recovering operation for the last copied document.