Sheet feeding or delivering – Feeding – With means to interrupt feeding
Patent
1992-01-15
1993-06-29
Olszewski, Robert P.
Sheet feeding or delivering
Feeding
With means to interrupt feeding
250223R, 356384, 356394, B65H 712
Patent
active
052227294
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention is directed generally to a method and apparatus for detecting superimposed sheets of paper. More particularly, the present invention is directed to a method and apparatus for detecting superimposed sheets of paper in a sheet transport path. Most specifically, the present invention is directed to a method and apparatus for detecting superimposed sheets of paper in a sheet transport path of a sheet fed rotary printing press. The sheets of paper are passed along a sheet feeding table and move between spaced light transmitters which may be laser diodes. The light reflected off the surface of the sheet or sheets has an angle with respect to a receiver which depends on the distance of the sheet or sheets from the light transmitter. By analyzing output voltages from receivers placed both above and below the sheet or sheets, a value corresponding to the thickness of the sheet or sheets can be ascertained. A thickness valve outside of a certain range is an indication of the superimposition of two or more sheets.
DESCRIPTION OF THE PRIOR ART
In sheet fed printing machines, a plurality of individual sheets are typically fed along a path of travel through various printing, drying, arranging and other handling and processing stations or areas. It is imperative that the sheets be positioned one after each other and that they not be overlapped or superimposed. If two or more sheets do become overlapped or superimposed the subsequent operation performed on the several sheets will quite probably not be performed correctly. Thus it is important that any overlapping or superimposition of sheets be detected and corrected.
One device which is useable to control overlapped sheets is disclosed in U.S. Pat. No. 4,397,460. In this device, the sheets on a sheet transport way are checked to see whether or not they are overlapped or superimposed. This is accomplished by providing two sequentially arranged sensor sensor devices positioned above the sheet transport way and two sequentially arranged sensor devices positioned beneath the sheet transport way or path. Each of these four sensor devices consists of a light emitting diode and of a phototransistor sensor which receives the light emitted from the diode and reflected from a surface of the sheet.
In the device for the control of overlapping sheets as set forth in U.S. Pat. No. 4,397,460 it is necessary that the sheets to be measured be guided essentially absolutely parallel to the transport way or path in the measuring range of the sequentially arranged sensor devices. This is accomplished by providing vacuum devices that feed the sheets against a surface whose location and position has previously been determined. In addition, in the prior art sheet control device of this patent, the degree of light reflection is measured and is thus dependant on the intensity of the reflection. This means that an accurate measurement can only be accomplished on a surface having a uniform degree or amount of reflection. This means that a measurement within a printed surface that may have been printed with several colors having differing intensities of reflection is not possible.
It will thus be apparent that a need exists for a method and apparatus for detecting superimposed sheets of paper which overcomes the limitations of the prior art. The assembly for detecting superimposed sheets in accordance with the present invention provides such a method and apparatus and is a substantial improvement over prior art devices.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a method and apparatus for detecting superimposed sheets.
Another object of the present invention is to provide a method and apparatus for detecting superimposed sheets on a sheet transport path.
A further object of the present invention is to provide a method and apparatus for detecting superimposed sheets on a sheet transport path of a sheet fed rotary printing press.
Yet another object of the present invention is to provide a method and apparatus for de
REFERENCES:
patent: 3186708 (1965-06-01), Hinz
patent: 3278754 (1966-10-01), Wallace
patent: 3565531 (1971-02-01), Kane et al.
patent: 3671726 (1972-06-01), Kerr
patent: 4286149 (1981-08-01), Ben-Nathan et al.
patent: 4397460 (1983-08-01), Milanes et al.
patent: 4773760 (1988-09-01), Makkonen
patent: 4937460 (1990-06-01), Duncan et al.
Opticator-Systembeschreibung, Published 1980.
Koenig & Bauer Aktiengesellschaft
Olszewski Robert P.
Reiss Steven M.
LandOfFree
Method and apparatus for detecting superimposed sheets of paper does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for detecting superimposed sheets of paper, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for detecting superimposed sheets of paper will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1750031