Helical scanning apparatus with one or more rows of scanning elements and an object of scanning disposed at an angle to the axis of a rotating drum to eliminate skew of scanning lines

A helical scanning apparatus with a plurality of scanning elements, comprising:

• a rotating drum disposed for rotation;
• feed means for feeding a rectangular object of scanning to the rotating drum and for winding the object around the drum so that one side of the object is inclined at a predetermined angle .theta. to the axis of the rotating drum;
• a scanning head movable in a direction parallel to the axis of the drum along the outer peripheral surface of the rotating drum on which the object is wound, said scanning head including a plurality of scanning elements for forming on the object scanning lines extending at right angles to the one side of the object as the drum rotates and the scanning head moves, the elements being arranged in a direction inclined at the angle .theta. to the axis of the drum;
• and
• drive means for rotating the rotating drum and for driving the scanning head in synchronism with the rotation of the drum;
• wherein said predetermined angle .theta. is given by .theta.=tan.sup.-1 .DELTA.L/L, where L is the circumference of the rotating drum and .DELTA.L is the distance covered by the scanning head while the drum makes one revolution.

A helical scanning apparatus with a plurality of scanning elements, comprising:

• a rotating drum disposed for rotation;
• feed means for feeding a rectangular object of scanning to the rotating drum and for winding the object around the drum so that one side of the object is inclined at a predetermined angle .theta. to the axis of the rotating drum;
• a scanning head movable in a direction inclined at the angle .theta. to the axis of the drum along the outer peripheral surface of the rotating drum on which the object is wound, said scanning head including a plurality of scanning elements for forming on the object scanning lines extending at right angles to the one side of the object as the drum rotates and the scanning head moves, the elements being arranged in a direction inclined at the angle .theta. to the axis of the drum;
• and
• drive means for rotating the rotating drum and for driving the scanning head in synchronism with the rotation of the drum;
• wherein said predetermined angle .theta. is given by .theta.=tan.sup.-1 .DELTA.L/L, where L is the circumference of the rotating drum and .DELTA.L is the distance covered by the scanning head while the drum makes one revolution.