Abstract: This invention pertains to a panelized modular construction system which employs a variety of square, rectangular and triangular panel shapes related to each other, being derived from a common grid subdivided cube. Combining these shapes of thickness practical for architectural application, these panels must be capable of being joined in many different angles and combinations along their sides, and in an unlimited combinations of angles at their corners. This construction system eliminates the strut and node framework typically found in many modular structures based on the geometry of various polyhedral forms. Located in the space between the sides of panels being joined, are simple connecting elements, independent of the panels, employed so as to join panels to each other in a manner that easily accommodate varying numbers and dihedral angles through almost 360 degrees.

Abstract: A toner concentration control test cycle in which a developed test area is formed on a photoconductor charged to a dark charge level. The optical reflectivity of the developed test area is sensed and the result used to replenish toner if indicated. During the test cycle, the magnetic brush bias potential is altered to produce development of the test patch in the gray area with the level of dark charge held constant at a predetermined nominal level. An electrostatic probe and associated circuitry are provided to maintain dark charge at the nominal level during the test cycle.

Abstract: A system for checking copy quality variables within an electrophotographic copier machine involving the production of a developed sample test area and a base reference test area on a photoreceptive surface. An optical transducer is used to view the test area and circuits are provided to produce an output signal indicative of quality. The circuit triggers itself by detecting a substantial change in transducer produced signal level when the sample test area is viewed, thus negating the requirement that the test circuits be operated under the control of the machine.

Abstract: An electrophotographic document copier machine of the transfer type where a detector is positioned subsequent to a detach station to sense whether copy receiving material has been successfully detached from the photoreceptive surface. The detector is comprised of a light source 40 to discharge the photoreceptive material 19 to a repeatable low level and an electrostatic probe 41 to sense that low level. When an unsuccessful detach operation occurs, the probe 41 senses the much higher voltage level present on the back side of copy receiving material which has passed under a transfer corona charge generator prior to reaching the detach station and light source 40.