Abstract: An electronic drive system applies a drive signal to an electrostatically actuated device such that a resulting electric field has a constant force. In various exemplary embodiments, the electronic drive system applies a drive signal to an electrostatically actuated fluid ejector that has a piston and a faceplate including a nozzle hole. A dielectric fluid to be ejected is supplied between the piston and the faceplate. The drive signal is applied to one of the piston and the faceplate. The drive signal generates an electric field across the fluid between the piston and the faceplate. The electric field causes the piston to be electrostatically attracted towards the faceplate so that a jet or drop of fluid is ejected through the nozzle hole of the faceplate. According to exemplary embodiments, the drive signal is from a constant current source or is reduced over the course of its lifetime.

Abstract: A method and apparatus for controlling the spacing of actuators within a common carriage or frame of a multiple actuator device is provided to render the actuator spacing insensitive to thermal deviations occurring among actuators due to variable thermal conditions within the carriage or frame. A first fixed actuator is connected to an underlying carriage or frame supporting a plurality of actuators and to each additional actuator via links of at least two dissimilar material, such that the respective coefficients of thermal expansion of the dissimilar materials enables the actuators to maintain their original spacing with respect to one another regardless of the thermal conditions within the carriage or frame.

Abstract: A printing process determines a maximum pixel printing rate of a printer. An area coverage of an image to be printed is estimated. When the area coverage multiplied by the printing speed exceeds the maximum pixel printing rate, the area coverage of the images to be printed is automatically reduced and the resulting image is printed.

Abstract: A smart direct memory access controller for data space transformation. The smart direct memory access controller can be used in computer systems to read and/or write data in a non-linear fashion in order to alter the organization of data stored within the computer system. The direct memory access controller has particular application in the electronic subsystem of a non-raster format electronic printer, such as a partial width array or full width array thermal ink jet printer. The smart direct memory access controller enables a non-raster format printer to access image organized in raster format, by viewing the data space as a non-linear or multi-dimensional memory. Memory addresses of the non-linear or multi-dimensional address space are a catenation of several data fields. Each field is one of the coordinates that defines the location of data within memory.

Abstract: A method and apparatus for automatically adjusting the quality of printing made by a scanning type printhead or printbar upon a recording medium advanced perpendicularly to the scanning direction. The scanning printbar includes sequentially printed segments in which the dots or pixels in a segment are printed simultaneously. A source of illumination is passed across a test pattern having features indicative of printhead alignment and discernible under the illumination. The source of illumination is connected to circuitry with determines the variation in light intensity of the test pattern. A value indicative of the misalignment is calculated and used to correct the timing of firing signals between the sequentially fired banks of nozzles of a printbar.

Abstract: Direct electrostatic printing apparatus including a cylindrically shaped donor structure for delivering imaging material such as toner particles to a printhead forming an integral part of the printing device. The printhead structure includes control electrodes and a shield electrode structure secured to opposite sides of an insulative base. The donor structure has a relatively small diameter compared to such devices of the prior art making it impossible to deliver adequate quantities of toner to some of the printhead apertures using electrical biasing techniques of the prior art. In the device disclosed, the printhead apertures are biased according to the aperture spacing from the donor structure. The magnitude of the bias or its duration applied to the apertures farther from the donor structure surface is such that toner delivery to those apertures is equal to that of all other apertures.

Abstract: Direct electrostatic printing apparatus including structure for delivering developer or toner particles to a printhead forming an integral part of the printing device. The printhead structure includes control electrodes and a shield electrode structure secured to opposite sides of an insulative base. The radius of the opening of a control electrode is smaller than the radius of a corresponding shield electrode opening resulting in larger peak potentials for controlling toner flow for the same voltage applied to the control electrode of a printhead aperture wherein the control electrode opening is larger than the opening in a corresponding shield electrode opening.