Abstract: The amount of achromatic toner used is reduced without decreasing adhesive force. A printer apparatus derives the densities of chromatic toner corresponding to the tone values of image data in the cyan, magenta and yellow format, and derives a total density by adding up the respective densities of the chromatic toner of cyan, magenta, and yellow. Then, the apparatus compares a threshold density such as 100% or 60% with the total density of the chromatic toner of cyan, magenta, and yellow. When the total density is higher than the threshold density, the apparatus sets the density of achromatic toner to 0. When the total density of the chromatic toner of cyan, magenta, and yellow is not higher than the threshold density, the apparatus sets the density of the achromatic toner to a value acquired by subtracting the total density from the threshold density.

Abstract: Disclosed is a linear actuator in which a screw shaft portion is integrally formed on the distal end side of the rotation shaft of the motor, and in which the coupling and one of the support bases are eliminated, thereby achieving a reduction in the number of parts and an improvement in positioning accuracy. The linear actuator includes a screw shaft portion formed on the distal end side of the rotation shaft of a motor and a nut portion threadedly engaged with the screw shaft portion, in which the screw shaft portion and the rotation shaft are formed as an integral unit using the same material and in a seamless state.