| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming apparatus with a decolorizing function which varies decolorization conditions according to a ground color of a sheet to make the remains of decolorization after the decolorization inconspicuous.SOLUTION: In an EEPROM, an optimal decolorization condition data table 42 comprising an optimal decolorization setting column 43, a chromaticity after the decoloriozation column 44, a sheet name column 45, a sheet ground color chromaticity column 46, and a ΔE minimum value column 47 is preliminarily stored. The ΔE minimum value is the minimum value among a plurality of pieces of ΔE to be calculated by a formula "ΔE=((L0*-Lα*)2+(a0*-aα*)2+(b0*-bα*)2)/2" based on chromaticity L0*, a0*, b0* of the ground color of the sheet and a plurality of pieces of chromaticity Lα*, aα*, bα* after the decolorization by decolorizing a print image of color fadable toner under a plurality of conditions to be obtained by combining various kinds of decolorization temperature and decolorization light quantity and is the chromaticity after the decolorization whose remains of the decolorization are the most inconspicuous to the ground color of the sheet. A CPU refers to the optimal decolorization condition data table 42 based on the ground color chromaticity of the sheet detected by a sensor to execute the decolorization by heating temperature (°C) and light quantity (mW/cm^2) corresponding to the ΔE minimum value. |
