Abstract: A densitometer using a light-to-frequency converter is disclosed. The converter outputs an oscillating signal with frequency characteristic of the incident light intensity. Digital controls may be input to the converter to set the frequency range of the output. The period count or frequency count of the converter output may be numerically divided to obtain a quotient within a small range. A lookup table is addressed according to the period count or frequency count, and return an offset scaled logarithm. The lookup table output is processed numerically to obtain a scaled density value. The converter may be adapted to process analog voltage inputs rather than light inputs. The logarithmic conversion then becomes applicable to a variety of fields besides densitometry.

Abstract: A multi-channel densitometer has a light sensor for each channel. The channels may be on a single circuit board, or may be on small, independently locatable probes. The outputs from the sensors are input to a single conveniently located controller circuit. The controller circuit provides power and control signals to the sensors, and processes the sensor outputs to obtain sample optical density. The multi-channel configuration saves space where the density measurements are needed, reduces the component count and cost, and facilitates calculation of multi-channel density functions, such as uniformity, transfer efficiency and color balance.

Abstract: An electrostatographic reproduction method and apparatus includes an electrostatic recording member moving in a process direction. A plurality of recording elements on a writer imagewise expose the recording member to form electrostatic latent images on the recording member. The writer includes driver circuitry for actuating selected recording elements. The exposed recording member is then moved through a development station to develop the latent images. The developed images are transferred to a record member. An operator selectable adjustment controller is manually adjusted for generating adjustments in operation of the recording elements to compensate for a misalignment of a process station in the apparatus.

Abstract: A method and apparatus of producing images includes a primary charger for depositing a primary electrostatic charge on an electrostatographic recording member. A first electrometer measures or senses the primary electrostatic charge. A light source such as an EL panel is enabled to reduce the level of the primary electrostatic charge to provide a reduced voltage level suited for recording on the image frame. The reduced voltage level on the image frame is imagewise modulated to form an electrostatic image. The electrostatic image is then developed with toner. The output of the EL panel is adjusted in response to a first factor related to a measured value of the level of the primary electrostatic charge and a set point value for the level of the reduced voltage level and a second factor related to error in the level of the reduced voltage level from the set point value for the reduced voltage level.

Abstract: A method is described of determining a sensitivity parameter of a toner monitor that forms a part of an electrostatographic recording apparatus having a development station that includes a mixture of a toner material in a toner developer composition wherein concentration of the toner material in the composition tends to change with use of the apparatus in making copies or prints. The method comprises providing in the development station a known weight or concentration of toner material as an initial condition of weight or concentration of toner material. The toner monitor generates a first signal representing a first output voltage of the toner monitor for the initial condition of weight or concentration of toner material. The electrostatographic recording apparatus is operated in a recording mode wherein the predetermined weight or concentration of toner material in the development station is reduced by a predetermined amount.