Information processor, image forming apparatus, information processing method, and non-transitory computer-readable medium

An image forming apparatus comprising:

• a signal output unit that outputs a first signal corresponding to the water content of the first sheet of paper not having a first image formed thereon and a second signal corresponding to the water content of the first sheet of paper which has the first image formed on a first surface thereof and which is heated to fix the first image;
• a storage unit that stores a first coefficient, which is preset on the basis of the relationship between a water content of a sheet of paper and a signal output from the signal output unit on the basis of the water content when a sheet of paper having each characteristic has the water content, in correspondence with the characteristics;
• a first acquisition unit that acquires the first signal output from the signal output unit;
• a second acquisition unit that acquires the second signal output from the signal output unit;
• a determination unit that determines the characteristic of the first sheet of paper;
• a first calculation unit that calculates a variation in water content of the first sheet of paper using the difference between the acquired first signal and the acquired second signal and the first coefficient stored in correspondence with the determined characteristic in the storage unit;
• a second calculation unit that calculates an expansion and contraction ratio of the first sheet of paper using the variation in water content calculated by the first calculation unit;
• a correction unit that corrects the size or position of a second image formed on a second surface of the first sheet of paper on the basis of the expansion and contraction ratio calculated by the second calculation unit;
• and
• an image forming unit that forms the first image on the first surface of the first sheet of paper, heats the first sheet of paper to fix the first image, and forms the corrected second image on the second surface of the first sheet of paper.

An information processing method in an information processor having a storage unit that stores a first coefficient, which is preset on the basis of the relationship between a water content of a sheet of paper and a signal output from a signal output unit on the basis of the water content when a sheet of paper having each characteristic has the water content, in correspondence with the characteristics, the method comprising;

• acquiring a first signal output from the signal output unit on the basis of the water content of a first sheet of paper not having a first image formed thereon;
• acquiring a second signal output from, the signal output unit on the basis of the water content of the first sheet of paper which has the first image formed on a first surface thereof and which is heated to fix the first image;
• determining the characteristic of the first sheet of paper;
• calculating a variation in water content of the first sheet of paper using the difference between the acquired first signal and the acquired second signal and the first coefficient stored in correspondence with the determined characteristic in the storage unit;
• and
• calculating an expansion and contraction ratio of the first sheet of paper using the variation in water content calculated by the first calculation unit.

A non-transitory computer-readable medium storing a program causing a computer to execute a process, the computer including a storage unit that stores a first coefficient, which is preset on the basis of the relationship between a water content of a sheet of paper and a signal output from a signal output unit on the basis of the water content when a sheet of paper having each characteristic has the water content, in correspondence with the characteristics, the process comprising:

• acquiring a first signal output from the signal output unit on the basis of the water content of a first sheet of paper not having a first image formed thereon;
• acquiring a second signal output from the signal output unit on the basis of the water content of the first sheet of paper which has the first image formed on a first surface thereof and which is heated to fix the first image;
• determining the characteristic of the first sheet of paper;
• calculating a variation in water content of the first sheet of paper using the difference between the acquired first signal and the acquired second signal and the first coefficient stored in correspondence with the determined characteristic in the storage unit;
• and
• calculating an expansion and contraction ratio of the first sheet of paper using the calculated variation in water content.