Abstract: The selective depopulation and/or repopulation of a full color image-next-to-image or image-on-image print engine for generating monochrome and/or highlight color images, utilizing a multiplicity of functionally-equivalent substations in tandem to compensate for the increase in printing speed.

Abstract: The selective depopulation and/or repopulation of a full color image-next-to-image or image-on-image print engine for generating monochrome and/or highlight color images, utilizing a multiplicity of functionally-equivalent substations in tandem to compensate for the increase in printing speed.

Abstract: Infra-Red Densitometer (IRD) readings are utilized to check the efficiency of two-pass cleaning of the black toner patch in a tri-level imaging apparatus. The IRD examines the background patch of the tri-level image and declares a machine fault if excessive toner is detected.

Abstract: In a single pass, tri-level imaging apparatus, machine cycle down is initiated when the color developer housing is functioning improperly. The voltage level of the color image prior to its development is read using an electrostatic voltmeter (ESV). The voltage level thereof is also read after development. The difference between these two readings is compared to an arbitrary target value and a machine cycle down is initiated if the difference is greater than the target.

Abstract: A method and apparatus for modifying an image data signal has a serial channel for obtaining a desired number of current M-bit patterns from the image data. Unique bit patterns are recognized in the current bit patterns, and new bit patterns are generated, each being specific to the detected unique bit pattern. The current and new bit patterns are combined in a predetermined manner to modify the image data as desired. For example, if the unique bit patterns are recognized as dark images on a leading edge of an image, the new bit patterns are generated and combined with the current bit patterns to lighten the image, particularly at the leading edge to improve stripping of the print media on which the image is printed from a fuser roll of the printer.

Abstract: An automatic development control system having a sensor providing a signal representative of developed toner mass on a patch sample on the photoreceptor. The signal is conveyed to a comparator through signal processing circuits for comparing with a reference signal. The signal processing circuits include digital to analog circuitry also capable of providing analog to digital conversion. The reference signal represents an undeveloped photoreceptor signal normalized to accommodate changing photoreceptor, sensor and operating environment characteristics. A dispenser solenoid activates a toner dispenser through an interrupt mechanism in given increments of time depending upon the error signals generated by the comparator.

Abstract: A development apparatus for developing electrostatic images upon a moving image-bearing surface including flow baffle means for regulating the flow of developer to the development zone. The baffle means is positioned between a supply means and the development zone and extends inwardly of each of the ends of a development means which preferably comprises a magnetic brush. The baffle means comprises stationary magnetic brushes formed of developer material. The stationary magnetic brushes are adapted to limit the flow of developer at the end portions of the development means.