Sheet feeding or delivering – Feeding – With means to interrupt feeding
Reexamination Certificate
1998-11-12
2001-06-05
Walsh, Donald P. (Department: 3653)
Sheet feeding or delivering
Feeding
With means to interrupt feeding
C271S259000, C271S265010
Reexamination Certificate
active
06241243
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and apparatus, acting as a safety device, for detecting abnormal paper feeding in a sheet printer and, more particulary, for detecting abnormal paper feeding in a sheet printer from a paper feeding portion to a printing unit portion thereof.
2. Description of the Prior Art
When performing a printing operation on a rotary printing press such as shown and described in assignee's U.S. Pat. No. 5,983,796, Ishida et al., Nov. 16, 1999, an operator operates the apparatus to feed printing papers piled on a paper feeding portion to a printing unit portion to start the printing operation. However, there are times when paper feeding is not performed normally due to “an improper setting of the paper feeding portion in various kinds of apparatuses” or “problems with the papers” or the like occurs. In response to such abnormal paper feeding, various kinds of safety apparatuses are provided in a paper register portion or the paper feeding portion itself so as to automatically detect this malfunction.
For example, as disclosed in Japanese Utility Model Publication No. 2-39808, there is shown apparatus for detecting abnormal paper feeding having a luminescent element and a photoreceptor element provided near a front lay in a feeder board of the sheet printer for detecting whether an abnormal paper feeding state with respect to the front lay of a sheet paper is large or small. The apparatus includes a control circuit which transmits a cylinder disengagement signal in synchronism with an operation of the printer and a control signal for discharging sheet paper as a special state when the abnormal paper feeding state is large on the basis of a detected output from the photoreceptor element, and transmits only the control signal in synchronism with an operation of the printer when the abnormal paper feeding state is small. In accordance with the foregoing apparatus, there is an advantage if the number of interruptions of operation can be reduced and the sheet paper, in a small abnormal paper feeding state, can be discharged as the special state after being printed so as to be easily separated from a normal sheet paper.
However, conventional safety apparatus including the apparatus mentioned above performs a function as a safety device by directly detecting “a positional shift of paper” or “overlapping papers” or the like. Accordingly, the following problems can occur during a printing operation.
(1) In the situation where paper does not reach a plurality of safety devices provided in the register portion even when a timing for feeding a paper is shifted, an accurate detection and judgement as to whether the paper feeding state can or not can not performed.
(2) Generally, since the safety device performs the foregoing detection at a fixed timing (within a time period),there is a case where the detection of the abnormal paper is delayed when the timing of the fed paper is shifted, and the safety apparatus cannot perform the function as the safety device.
(3) There are times when the fed paper is interrupted by the register portion or a member provided on the feeder board, resulting in too many papers flowing into the printing unit portion, and causing damage or trouble in the apparatus or a blanket or the like.
(4) When a malfunction mentioned above is generated, it is necessary for the operator to always observe whether or not the paper fed from the paper feeding portion properly enters the register portion.
(5) When a malfunction mentioned above is generated, not only is some damage caused, but also a loss time for a post operation is generated therewith, so that not only are productivity and printing quality reduced, but also the work load for the operator is increased.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a method and apparatus for detecting an abnormal paper feed which can increase the work load on an operator and lessen productivity and printing quality by improving a detecting function with respect to a timing shift of fed paper to avoid various kinds of malfunctions previously caused by abnormal paper feeding.
In order to achieve the object mentioned above and in accordance with the present invention, there is provided a method of detecting an abnormal paper feed comprising the steps of detecting the number of papers fed to a printer based on a paper feeding signal generator generating a signal in response to paper feeding after the start of paper feeding, detecting whether or not paper exists on a feeder board by a paper existence detector located on the feeder board, and detecting an abnormal paper feed state in accordance with a relation between the number of the papers fed and the existence or non-existence of detected paper.
In the method of detecting abnormal paper feeding according to the above, an abnormal paper feed is judged to exist in the case where said paper existence detector does not detect the existence of paper on the feeder board when said number of the fed papers is equal to a preset fixed number.
In the method of detecting an abnormal paper feeding according to the above, an abnormal paper feeding is judged to exist in the case when said paper existence detector detects the existence of paper when said number of the fed papers is less than a preset fixed number.
Further, in accordance with the present invention, there is provided an apparatus for detecting abnormal paper feed, which is used for the method of detecting an abnormal paper feed according to the above comprising, a paper feeding start signal generator, a paper feeding signal generator generating a signal in response to paper fed to a printer, a paper existence detector located on a feeder board, and a control apparatus having number of fed paper memory means for storing a number of papers fed to the printer until a first paper comes to the paper existence detector after the paper feed is started, and detecting an abnormal paper feed from a relation among the number of fed papers from said paper feeding signal generator, the number of the fed papers stored in said number of fed paper memory means and the detected signal of said paper existence detector so as to output a paper feed stop signal.
In the apparatus for detecting an abnormal paper feed according to the above, the control apparatus outputs a paper feeding stop signal by judging an abnormal paper feeding in the case when the paper existence detector does not detect the existence of paper when the number of the fed paper for the printer, after the paper feeding is started, equals to the number of the fed paper stored in said number of fed paper memory means.
In the apparatus for detecting an abnormal paper feed according to the above, the control apparatus outputs a paper feeding stop signal by judging abnormal paper feed in the case that the paper existence detector detects the paper existence when the number of the fed paper for the printer, after the paper feeding is started, is less than the number of the fed paper stored in said number of fed paper memory means.
In accordance with the method of and the apparatus for detecting abnormal paper feed mentioned above, an abnormal paper feed due to a timing shift from the paper feeding portion to the register portion can be automatically and accurately detected, so that a paper feed to the printing unit thereafter can be securely stopped.
REFERENCES:
patent: 3970384 (1976-07-01), Yamamoto et al.
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patent: 4203589 (1980-05-01), Arrasmith
patent: 4310153 (1982-01-01), Kikuchi
patent: 5280322 (1994-01-01), Kono
patent: 5544580 (1996-08-01), Takahashi
patent: 5580046 (1996-12-01), Beaufort et al.
patent: 5983796 (1999-11-01), Ishida et al.
patent: 0480316 (1992-04-01), None
patent: 2071064 (1981-09-01), None
patent: 239808Y2 (1990-10-01), None
patent: 239808 (1990-10-01), None
Patent Abstracts of Japan, vol. 017, No. 155 (M-1388), Mar. 16, 1993—Abstract for JP 04-323044A, published Nov. 12, 1992.
Patent Abstracts o
Hatakeyama Yoshiro
Ishida Masaaki
Birch & Stewart Kolasch & Birch, LLP
Jones David A.
Komori Corporation
Walsh Donald P.
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