Stack conditioning apparatus and method for use in bookbinding

Apparatus of conditioning an edge of a single sheet of paper comprising:

• a first folding member which includes first and second folding surfaces disposed at a first intermediate angle of less than 120 degrees, with the first and second folding surfaces meeting at a first location;
• a second folding member which includes third and fourth folding surfaces disposed at a second intermediate angle of less than 120 degrees, with the third and fourth folding surfaces meeting at a second location;
• first apparatus configured to fold a section of the sheet which extends to the edge of the sheet over the first folding member in a first folding direction so that a first bending line is formed in the sheet at the first location along substantially a full length of the edge of the sheet, with the first apparatus together with the first and second folding members forming part of a sheet positioning mechanism so that the first bending line is disposed in a region of the sheet between 0.030 and 0.050 inches from the edge of the sheet, and with the sheet being folded at the first intermediate angle and further configured to fold a section of the sheet which extends to the edge of the sheet over the second folding member in a second folding direction, opposite the first folding direction, so that a second bending line is formed in the sheet at said second location along substantially a full length of the edge of the sheet, with the second bending line being disposed in a region of the sheet between 0.030 and 0.050 inches from the edge of the sheet, and with the sheet being folded at the second intermediate angle.

Apparatus of conditioning an edge of a single sheet of paper having first and second opposite surfaces, said apparatus comprising:

• a first folding member which includes first and second folding surfaces disposed at a first intermediate angle of less than 120 degrees, with the first and second folding surfaces meeting at a first location;
• a second folding member which includes third and fourth folding surfaces disposed at a second intermediate angle of less than 120 degrees, with the third and fourth folding surfaces meeting at a second location;
• first apparatus configured to fold a section of the sheet which extends to the edge of the sheet over the first folding member in a first folding direction so that a first bending line is formed in the sheet at the first location along substantially a full length of the edge of the sheet, and with the sheet being folded at the first intermediate angle and further configured to fold a section of the sheet which extends to the edge of the sheet over the second folding member in a second folding direction, opposite the first folding direction, so that a second bending line is formed in the sheet at said second location along substantially a full length of the edge of the sheet, and with the sheet being folded at the second intermediate angle, with the first apparatus together with the first and second folding members forming part of a sheet positioning mechanism so that the first and second locations are respectively located a sufficiently short distance from the edge of the sheet such that when the sheet is folded in the first and second folding directions, the edge of the sheet will tend to split in a region intermediate the first and second opposite surfaces.