Image forming apparatus and method of correcting positional deviation of sheet

The image forming apparatus, comprising:

• a detecting device configured to detect a position of a sheet, the detecting device including a plurality of contact image sensors arranged along a sheet conveying direction of the sheet;
• a pair of sheet conveying bodies configured to convey the sheet and correct a positional deviation of the sheet;
• an image forming device configured to form an image on the sheet;
• and
• circuitry configured to:
• calculate a first positional deviation amount of the sheet based on a first detection result of the position of the sheet by the detecting device;
• cause the pair of sheet conveying bodies to correct the positional deviation of the sheet based on the first positional deviation amount;
• calculate a second positional deviation amount of the sheet based on a second detection result of the position of the sheet by the detecting device;
• and
• cause the image forming device to correct a positional deviation of an image forming position on the sheet based on the second positional deviation amount,
• wherein the plurality of contact image sensors includes a first contact image sensor, a second contact image sensor, and a third contact image sensor disposed from an upstream side to a downstream side of the sheet conveying direction,
• wherein the circuitry is configured to:
• cause the first contact image sensor and the second contact image sensor to detect the position of the sheet;
• calculate the first positional deviation amount of the sheet based on detection results of the position of the sheet by the first contact image sensor and the second contact image sensor;
• cause the pair of sheet conveying bodies to correct the positional deviation of the sheet based on the t positional deviation amount;
• cause the second contact image sensor and the third contact image sensor to detect the position of the sheet;
• calculate the second positional deviation amount of the sheet based on detection results of the position of the sheet by the second contact image sensor and the third contact image sensor;
• and
• cause the pair of sheet conveying bodies to perform re-correction of the positional deviation of the sheet based on said second positional deviation amount, and
• wherein the circuitry is configured to perform a feedback control during the re-correction.

A method of correcting a positional deviation of a sheet, the method comprising:

• detecting a position of the sheet by at least one of an image capturing device and a plurality of image sensors;
• calculating a first positional deviation amount of the sheet based on a first detection result of the position of the sheet;
• causing a pair of sheet conveying bodies to correct the positional deviation of the sheet based on the first positional deviation amount;
• detecting the position of the sheet again;
• calculating a second positional deviation amount of the sheet based on a second detection result of the position of the sheet;
• causing an image forming device to correct an image forming position on the sheet based on the second positional deviation amount;
• causing the image forming device to correct the image forming position in a width direction of the sheet;
• generating image data of an image to be formed on the sheet by the image forming device;
• generating ink discharge data used to determine allocation of a plurality of ink discharging nozzles to discharge liquid onto the sheet based on the image data;
• sliding the allocation of the plurality of ink discharging nozzles determined based on the ink discharge data in the width direction of the sheet;
• and
• causing the image forming device to correct the image forming position to the sheet in the width direction of the sheet.