Abstract: A method of manufacturing an image forming apparatus includes evaluating, based on a pair comparison method, sounds generated when forming an image, carrying out a multiple linear regression analysis using a difference between scores of the evaluation as a target variable and a difference between psycho-acoustic parameter values as an explanatory variable, deriving formula concerning the difference in scores of sound quality from a result of the analysis, substituting an average of the psycho-acoustic parameter values used to derive the formula into the formula, defining discomfort of the sound when all the parameter values are average values as zero, and deriving a sound quality evaluation formula, and designing each unit of the apparatus based on the sound quality evaluation formula.

Abstract: A discomfort index of sound is obtained by an equation using the loudness value, sharpness value, tonality value and impulsiveness value of psychoacoustic parameters obtained from sounds at a position away from the end face of an image formation apparatus by 1 m. The discomfort index is decreased by reducing the high frequency component, charging noise, metallic impulsive sound and the like of the image formation apparatus, to thereby contribute to the improvement of the use environment.

Abstract: In an image formation apparatus, a discomfort probability P, calculated from an expression (a), fulfills a condition (b). Here, {circumflex over (P)}im=1/{1+exp [?z]}??(a) {circumflex over (P)}im?0.2725·ln(ppm)?0.6331??(b) where z=A×sound pressure level i+B×loudness i+C×sharpness i+D×tonality i+E×impulsiveness i+F, i=1, 2, 3, . . . , n, A, B, C, D, and E are regression coefficients of parameters, and F is intercept, and A, B, C, D, E, and F satisfy the inequalities 0.142?A?0.183, 0.300?B?0.389, 1.097?C?1.265, 9.818?D?11.516, 2.588?E?3.240, ?18.844?F?14.968, ppm is a printing speed per minute for A4 horizontal size paper.

Abstract: A method of manufacturing an image forming apparatus includes evaluating, based on a pair comparison method, sounds generated when forming an image, carrying out a multiple linear regression analysis using a difference between scores of the evaluation as a target variable and a difference between psycho-acoustic parameter values as an explanatory variable, deriving formula concerning the difference in scores of sound quality from a result of the analysis, substituting an average of the psycho-acoustic parameter values used to derive the formula into the formula, defining discomfort of the sound when all the parameter values are average values as zero, and deriving a sound quality evaluation formula, and designing each unit of the apparatus based on the sound quality evaluation formula.

Abstract: A discomfort index of sound is obtained by an equation using the loudness value, sharpness value, tonality value and impulsiveness value of psychoacoustic parameters obtained from sounds at a position away from the end face of an image formation apparatus by 1m. The discomfort index is decreased by reducing the high frequency component, charging noise, metallic impulsive sound and the like of the image formation apparatus, to thereby contribute to the improvement of the use environment.

Abstract: In an image formation apparatus, a discomfort probability P, calculated from an expression (a), fulfills a condition (b).

Abstract: A discomfort index of sound is obtained by an equation using the loudness value, sharpness value, tonality value and impulsiveness value of psychoacoustic parameters obtained from sounds at a position away from the end face of an image formation apparatus by 1 m. The discomfort index is decreased by reducing the high frequency component, charging noise, metallic impulsive sound and the like of the image formation apparatus, to thereby contribute to the improvement of the use environment.

Abstract: A discomfort index of sound is obtained by an equation using the loudness value, sharpness value, tonality value and impulsiveness value of psychoacoustic parameters obtained from sounds at a position away from the end face of an image formation apparatus by 1 m. The discomfort index is decreased by reducing the high frequency component, charging noise, metallic impulsive sound and the like of the image formation apparatus, to thereby contribute to the improvement of the use environment.