Curl correcting unit and image forming apparatus

A curl correcting unit for performing curl correction on a sheet on which an image is formed by an image forming apparatus, comprising;

• a first curl correcting section that applies pressure to the sheet and performs curl correction in a direction to raise an edge portion of the sheet;
• a second curl correcting section that applies pressure to the sheet and performs curl correction in a direction to lower an edge portion of the sheet, and is positioned downstream of a sheet transporting path with respect to the first curl correcting section;
• and
• a control section that, after the sheet has passed through the first curl correcting section, drives the second curl correcting section and performs curl correction on a trailing edge portion of the sheet.

An image forming apparatus for sequentially forming an image while continuously transporting a plurality of sheets with a predetermined space interposed therebetween, comprising:

• a first curl correcting unit that applies pressure to a sheet being transported and performs curl correction in a direction to raise an edge portion of the sheet;
• and
• a second curl correcting unit that applies pressure to the sheet being transported and performs curl correction in a direction to lower the edge portions of the sheet,
• wherein the second curl correcting unit is disposed at a location away from the first curl correcting unit by a predetermined space, and the space between the first curl correcting unit and the second curl correcting unit is smaller than the space between sheets continuously transported.

An image forming apparatus comprising:

• an image forming part that forms an image on a sheet on the basis of input image information;
• a curling state detecting part that detects a state of curling which may occur on the sheet on which the image is formed by the image forming part;
• a first pressure part that applies pressure to one surface of the sheet on which the image is formed by the image forming part;
• a second pressure part that applies pressure to the other surface of the sheet on which the image is formed by the image forming part, the second pressure part being disposed downstream of the first pressure part;
• and
• a driving part with a driving element in the driving part has a cam mechanism that drives the first pressure part and the second pressure part by the same driving part on the basis of a result of the detection made by the curling state detecting part;
• wherein the cam mechanism is integrally provided with two cams which differ from each other in phase, and forms three modes for controlling the first pressure part and the second pressure part by using a single sensor and a single light blocking disk.

An image forming apparatus comprising:

• an image forming part that forms an image on a sheet on the basis of input image information;
• a curling state detecting part that detects a state of curling which may occur on the sheet on which the image is formed by the image forming part;
• a first pressure part that applies pressure to one surface of the sheet on which the image is formed by the image forming part, wherein the first pressure part is provided with a first hard roll and a first soft roll facing the first hard roll and held by a rotatable first lever;
• a second pressure part that applies pressure to the other surface of the sheet on which the image is formed by the image forming part, wherein the second pressure part is provided with a second hard roll and a second soft roll facing the second hard roll and held by a rotatable second lever, the second pressure part being disposed downstream of the first pressure part;
• and
• a driving part that drives the first pressure part and the second pressure part by the same driving part on the basis of a result of the detection made by the curling state detecting part.