| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming apparatus including a fixing device that performs accurate reduction of curl in consideration of a difference in curl between the types of sheets.SOLUTION: There is provided an image forming apparatus including a fixing device that forms a nip part with heating means and pressure means, calculation means for predicting curl of a sheet generated in the fixing device; and a storage part that stores a function related to the property and contraction coefficient of the sheet, where the calculation means calculates a temperature distribution in the sheet thickness direction according to the thickness of the sheet, a sheet heating time calculated from the sheet conveying speed and the width of the nip part, the initial moisture content of the sheet measured before conveyance to the fixing device, and a measured heating temperature of the nip part; calculates the moisture content distribution in the thickness direction of the sheet according to porosity and a moisture dispersion coefficient acquired from the storage part and the temperature distribution; calculates the contraction coefficient of the front and rear faces of the sheet according to the heating temperature and the moisture content distribution by using the function related to the contraction coefficient, and predicts the amount of curl from the difference between the contraction coefficients.SELECTED DRAWING: Figure 8 |
