Overlap detection apparatus and overlap detection method

An overlap detection apparatus mounted to a printing press in which sheets of paper are successively conveyed while each being displaced by a given amount from an upstream sheet of paper in a sheet conveying direction and overlapping the same, comprising:

• a sheet detection sensor for detecting whether a portion of the sheets passing a given position is a non-overlapping portion or an overlapping portion;
• a signal output section for outputting an overlapping signal on the basis of the detected result of the sheet detection sensor, in which the overlapping signal takes a first form for the overlapping portion and takes a second form for the non-overlapping portion;
• and
• a determination section for determining that the sheets of paper are being correctly conveyed while each being displaced by a given amount from an upstream sheet of paper in the conveying direction and overlapping the same, when the timing, at which the form of the overlapping signal is changed from the first form to the second form or vice versa, relative to a printing reference of the printing press, is equal to a given reference timing;
• and determines that the sheets of paper are not being correctly conveyed, when the timing, at which the form of the overlapping signal is changed from the first form to the second form or vice versa, relative to the printing reference of the printing press, is not equal to the given reference timing.

An overlap detection method of determining whether or not sheets of paper are being correctly conveyed in a printing press, in which the sheets of paper are conveyed while each being displaced by a given amount from an upstream sheet of paper in a sheet conveying direction and overlapping the same, on the basis of detection of an overlapping state of the sheets of paper, comprising:

• detecting whether a portion of the sheets passing a given position is a non-overlapping portion or an overlapping portion by a sheet detection sensor;
• outputting an overlapping signal on the basis of the detected result of the sheet detection sensor, in which the overlapping signal takes a first form for the overlapping portion;
• and
• determining that the sheets of paper are being correctly conveyed while each being displaced by a given amount from an upstream sheet of paper in the conveying direction and overlapping the same when a portion of the overlapping signal taking the first form is equal to a given reference portion, and determining that the sheets of paper are not being correctly conveyed when the portion of the overlapping signal taking the first form is not equal to the given reference portion.

An overlap detection method of determining whether or not sheets of paper are being correctly conveyed in a printing press, in which the sheets of paper are conveyed while each being displaced by a given amount from an upstream sheet of paper in a sheet conveying direction and overlapping the same, on the basis of detection of an overlapping state of the sheets of paper, comprising:

• detecting whether a portion of the sheets passing a given position is a non-overlapping portion or an overlapping portion by a sheet detection sensor;
• outputting an overlapping signal on the basis of the detected result of the sheet detection sensor, in which the overlapping signal takes a first form for the overlapping portion and takes a second form for the non-overlapping portion;
• and
• determining that the sheets of paper are being correctly conveyed while each being displaced by a given amount from an upstream sheet of paper in the conveying direction and overlapping the same when the timing, at which the form of the overlapping signal is changed from the first form to the second form or vice versa, relative to a printing reference of the printing press, is equal to a given reference timing, and determining that the sheets of paper are not being correctly conveyed when the timing, at which the form of the overlapping signal is changed from the first form to the second form or vice versa, relative to the printing reference of the printing press, is not equal to the given reference timing.