Image forming apparatus, printing system, and image forming device

9, The image forming apparatus according to claim 1, further comprising:

• a feeding unit that feeds a recording sheet having a size of A4 serving as the recording medium;
• a developing unit that forms an image on the recording sheet by use of a developing agent;
• and
• a fixing unit that comprises a heating roller and a pressure roller, the pressure roller having an elastic body layer on a surface thereof, the pressure roller being provided so as to face the heating roller to press the recording sheet with the image formed thereon against the heating roller;
• wherein assuming that a nip portion is formed by deforming the elastic body layer in accordance with a surface shape of the heating roller when the pressure roller is pressed toward the heating roller, θ (°) is a peeling angle between a tangential line of the heating roller and a discharge direction of the recording sheet at the most downstream point of the nip portion in a recording sheet feed direction on a plane orthogonal to a central axis of the heating roller, Dpr (mm) is a diameter of the pressure roller, and Wnip (mm) is a length for which the recording sheet contacts the nip portion in the feed direction, the curl forming part controls a temperature Thr (° C.) of the heating roller so as to satisfy an inequality shown in the following expression:
• 0.55×Thr−2.36×θ−1.59×Dpr+8.62×Wnip<124.

A printing system comprising:

• an image reading device that reads a document and comprises:
• a document table on which the document is placed;
• a document table cover having one end capable of swinging about the other end thereof and a document pressing surface formed with an opening, the document table cover rotating in a first direction away from the document table and in a second direction toward the document table, the document pressing surface being capable of pressing the document;
• and
• a document pre-pressing member that is received in the opening and has one end capable of swinging about the other end thereof, the document pre-pressing member being capable of rotating in the first direction and in the second direction, the document pre-pressing member being capable of pressing a part of the document on the document table in a state where the document table cover is open;
• and
• an image forming device that communicates with the image reading device and forms an image on a recording medium on the basis of image data obtained by reading the document though the image reading device, the image forming device comprising a curl forming part that curls the recording medium so that a surface of the recording medium formed with the image thereon is to be concave.

An image forming device comprising:

• a developing unit that forms an image on a recording sheet having a size of A4 by use of a developing agent;
• a fixing unit that comprises a heating roller and a pressure roller, the pressure roller having an elastic body layer on a surface thereof, the pressure roller being provided so as to face the heating roller to press the recording sheet with the image formed thereon against the heating roller;
• and
• assuming that a nip portion is formed by deforming the elastic body layer in accordance with a surface shape of the heating roller when the pressure roller is pressed toward the heating roller, θ (°) is a peeling angle between a tangential line of the heating roller and a discharge direction of the recording sheet at the most downstream point of the nip portion in a recording sheet feed direction on a plane orthogonal to a central axis of the heating roller, Dpr (mm) is a diameter of the pressure roller, and Wnip (mm) is a length for which the recording sheet contacts the nip portion in the feed direction, a curl forming part that controls a temperature Thr (° C.) of the heating roller so as to satisfy an inequality shown in the following expression:
• 0.55×Thr−2.36×θ−1.59×Dpr+8.62×Wnip<124.

An image forming apparatus comprising:

• an image reading unit that reads a document and comprises:
• a document table on which the document is placed;
• a document table cover having one end capable of swinging about the other end thereof, the document table cover rotating in a first direction away from the document table and in a second direction toward the document table, the document table cover being capable of pressing the document;
• and
• a positioning portion that positions the document and is provided on the side of the other end of the document table cover;
• and
• an image forming unit that forms an image of the document read by the image reading unit on a recording medium, the image forming unit comprising a curl forming part that curls the recording medium so that a surface of the recording medium formed with the image thereon is to be concave.