Abstract: An apparatus is provided for determining the response of an electrometer used in an electrophotographic recording apparatus. The apparatus includes a movable base disposed adjacent said electrometer. The base includes a non-conductive material. A conductive pattern is disposed on the base. The conductive pattern is electrically connected to a variable power supply. A motor moves or drives the base past the electrometer. The motor is controlled by a motor control to vary the speed of movement of said base. A method is also provided for determining the response of an electrometer used in an electrophotographic recording apparatus. An electrometer to be tested is selected and the operational parameters of the electrometer are dynamically tested.

Abstract: An optical device for indicating the position of a flexible web in a machine. The device is mounted in a fixed bracket and a collimated beam is reflected from the web onto a screen to produce a visible light spot. The location of the light spot on the screen is directly related to the position of the web.

Abstract: A cooling system is provided for a thermal print head that has a thermal dye transfer portion and a rear surface. The cooling system includes a bracket defining an open reservoir, and is attached to the print head so that the rear surface of the print head closes the reservoir. Cooling fluid is pumped into the reservoir and brought into contact with the rear surface to effect cooling of the print head. The bracket is removably attached using bolts with o-rings and a sealing gasket interposed between the bracket and print head.