Sheet suction device, sheet conveyor, printer, and suction area switching device

A sheet suction device comprising:

• a sheet bearer to bear a sheet on a bearing area of a circumferential surface of the sheet bearer and rotate, the sheet bearer having a plurality of suction holes on the bearing area;
• a suction generator to suck the sheet through the plurality of suction holes, the suction generator connecting to the plurality of suction holes via a tube;
• a first structure between the plurality of suction holes and the suction generator, the first structure having a plurality of hole rows including a plurality of holes, the plurality of holes in each of the plurality of hole rows arranged in a circumferential direction of the first structure, the plurality hole rows arranged in a radial direction of the first structure;
• and
• a second structure between the plurality of suction holes and the suction generator, the second structure having grooves arranged in the radial direction, each of the grooves extending in the circumferential direction,
• wherein, when the first structure rotates with respect to the second structure, the number of holes communicating with the grooves among the plurality of holes is changed to change the number of the plurality of suction holes communicating with the suction generator, and
• wherein the plurality of holes includes two or more holes that simultaneously communicate with the suction generator when the first structure rotates by a unit rotation amount.

A suction area switching device between a plurality of suction holes on a bearing area of a circumferential surface of a sheet bearer to bear a sheet and a suction generator to suck the sheet through the plurality of suction holes, the suction generator connecting to the plurality of suction holes via a tube, the suction area switching device comprising:

• a first structure having grooves arranged in a radial direction of the first structure, each of the grooves extending in a circumferential direction of the first structure;
• and
• a second structure having a plurality of hole rows including a plurality of holes, the plurality of holes in each of the plurality of hole rows arranged in the circumferential direction, the plurality hole rows arranged in the radial direction,
• wherein, when the first structure rotates with respect to the second structure, the number of holes communicating with the grooves among the plurality of holes is changed to change the number of the plurality of suction holes communicating with the suction generator, and
• wherein the plurality of holes includes two or more holes that simultaneously communicate with the suction generator when the first structure rotates by a unit rotation amount.