Improved apparatus and methods of sensing or monitoring body orientation and motion and measuring range of motion for use in athletic training and physical rehabilitation and evaluation. When a black dot is formed between monochrome-black dots adjacent in the sub-scanning direction, a dot of color-mixed black which is a mixture of the other three colors is formed between the monochrome-black dots. The rotary slide valve further comprises a centering ring which is non-rotatably connected with the output shaft, and arm inlet to the pressure chamber. At a suitable point in time these are placed on the collection conveyor using an ejection device. A method of modifying the settings of a driven pulley and a method of assembling a driven pulley also disclosed.