Savin Business Machines Corporation

Mitutoyo Manufacturing Co., Ltd.

Charles B Clark

James A Baer

Louis F Schaefer

Joseph S Eckerle

Hugh F Frohbach

Russell T Wolfram

A capacitance type displacement measuring instrument is disclosed in which a change in electric capacity between electrodes due to a change in displacement between two members movable relative to each other is detected on the basis of a change in phase of a detection signal and a displacement value between the two members is measured from the change in the capacity. AC signals are successively applied to transmitting electrodes provided on one of the members at a predetermined pitch by a multiplexer and signals induced in transfer electrodes at a predetermined pitch differing from the aforesaid pitch of the transmitting electrodes are received by pickup electrodes provided on the aforesaid one of the members. The relative displacement is detected from a change in phase of a received signal of substantially triangular waveform, which are obtained by the pickup electrode.

Capacitance type displacement measuring instrument

A toner concentration detecting and toner replenishing system for use in an electrostatic copier having a magnetic brush which carries dry developer comprising a mixture of ferromagnetic carrier particles and toner particles into contact with the surface of a photoconductor upon which a latent electrostatic image has been formed, in which system a quantity of developer is removed from the magnetic brush after development of the image and the brush leaves the surface. The removed developer is directed into a dielectric tube having a restricted outlet which inhibits unstable flow through the tube so that developer in the tube determines the inductance of a coil surrounding the tube. The coil is one element of the tuned circuit of a sensing oscillator, the output frequency of which is compared with that of a tunable reference oscillator to provide a frequency difference signal which is a measure of the relative proportion of toner to carrier in the developer. This frequency difference signal is employed to actuate a toner replenishing system to feed toner from the supply to the developer supply as required to maintain the toner concentration substantially constant.

Toner concentration detector

Toner concentration detector for dry powder magnetic brush toning system

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Los Altos, CA, United States of America

Charles B Clark