Eastman-kodak Company

Gerard R Sirand-Rey

Claude G Goumont

Guy Claude Travot

Jacques Roussilhe

Alain Andre Charret

A device for automatically measuring a concentration of a developing agent in a developing bath includes a voltage generator capable of generating at least one voltage ramp provided to feed a three-electrode cell; a potentiostat provided to maintain a constant potential difference between two electrodes; a peak detector provided to identify the maximum current flowing in the three-electrode cell that corresponds to the developing agent concentration; and a display unit provided to show the maximum current.

Automatic measuring device for the concentration of a developing agent

The invention concerns a method for controlling the activity of a development composition which comprises, as a developing agent, an organometallic complex. The method includes measuring the variations in optical density difference of the composition that varies with the degree of oxidation of the organometallic complex. The method also makes it possible to regenerate the development composition by means of an electrolysis current. A device for controlling the activity of the development composition includes two light-emitting diodes of different wavelengths, the light beams of which pass through the development composition, and photodiodes to receive transmitted light.

Method for controlling the activity of an inorganic development

An optical detector for magnetic fields detects rotations in the polarization of a beam of polarized light caused by the magnetic fields. A modulator responsive to a fixed frequency signal introduces a fixed frequency of oscillation in the polarization of the light beam. The output signal of a polarization detector is filtered by a band pass filter and is fed, along with the fixed frequency signal, to a phase detector. The output of the phase detector is inverted and used as a feed-back signal to the modulator to cancel the rotation in polarization caused by the magnetic field. This feedback signal is also the final output signal of the detector.

Optical detector for magnetic fields employing feedback circuitry

A method and apparatus are disclosed for retrieving magnetically recorded information by optical means. The magnetic recording is irradiated by a beam of coherent light whose plane of polarization is periodically varied. The light which is transmitted or reflected from the recording medium is analyzed in order to retrieve the magnetically recorded information.

Growing community of inventors

Chalon sur Saone, France

Gerard R Sirand-Rey