Patent ID: 6862417

Claim:
An image formation apparatus having an arrangement so that a discomfort probability P, calculated from an expression (a), fulfills a condition (b), wherein the discomfort probability P is calculated using a sound pressure level value, a loudness value of a psycho-acoustics parameter, a sharpness value, a tonality value, and an impulsiveness value obtained from operation noise at a position with a distance from an end surface of the image formation apparatus, {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 recording medium.