Abstract: An improved and lower cost color spectrophotometer, especially suitable for an on-line color printer color control system, in which plural different spectra LEDs sequentially perpendicularly illuminate a common and substantially circularly illuminated color test area, which may be variably spaced and variably oriented relative to the spectrophotometer, through a common central lens system, and also the reflected illumination therefrom may be measured at 45 degrees thereto by averaging the outputs of photodetectors spaced around that circularly illuminated color test area, to provide reduced sensitivity to the variable angular or azimuthal orientation of the color test area relative to the spectrophotometer, and which photodetectors may be so illuminated by 1:1 optics for spatial insensitivity.

Abstract: A developability sensing system with an optical sensor for measuring the density of imaging material samples on an imaging surface of a printer, with an illumination source and photosensor system for measuring the amount of reflected illumination from the imaging materials. A first lens system and its first photosensor may receive both specularly and diffusely reflected illumination from certain imaging materials. A separate lenslet system is positioned outside of the first lens system. It may comprise one to four spaced apart generally cylindrical lenslets with a central axis generally perpendicular to the imaging material sample and an end surface facing the imaging material sample defined by a segment of a hyperbolic curved surface to form a rotationally symmetrical lens with a hyperbolic cross-section.

Abstract: A low ink sensing system is combined with an ink cartridge detection system to enable a more efficient ink jet printer. An ink container which supplies ink to an associated printhead is modified by the incorporation of two light directing elements, in the preferred embodiment, a faceted prism and a roof mirror, into a transparent wall of the container housing. The cartridge, comprising the ink container and associated printhead, is mounted on a scan carriage. Periodically, the carriage is conveyed to a sensing station comprising a pair of light sources and a commonly used photosensor. A first light source is energized and a beam of light is directed to a location where the roof mirror, would be positioned if the cartridge is present. If the cartridge is absent, lack of a reflected return signal is sensed, indicating a cartridge has not been inserted. Print operation is halted until a cartridge is inserted.

Abstract: An improved spectrophotometer for non-contact measuring of the colors of colored target areas, especially, test patches on moving printed test sheets in an unrestrained normal output path of a color printer, which test patches may be sequentially angularly illuminated with multiple different colors, with a photosensor providing electrical signals in response, the spectrophotometer having a lens system for transmitting that reflected illumination from the test patch to the photosensor with a lens magnification ratio of approximately one to one. The exemplary spectrophotometer provides noncontact color measurements of moving color target areas variably displaced therefrom within normal paper path baffle spacings, with a displacement insensitivity of at least 6 millimeters about a nominal target to spectrophotometer separation.

Abstract: An apparatus for rapidly determining and correcting the position of a scanning light beam. The apparatus includes a linear position sensor that senses the position of the scan line and a circuit that produces a position signal from the sensed scan line position. A closed loop scan line control system further includes a scan line correction mechanism that adjusts the position of the scan line such that the position of the scan line is corrected for each individual polygon facet. Beneficially, the closed loop scan line correction mechanism includes a mover that moves an optical element, such as a mirror or lens, that adjusts the scan line position.

Abstract: A light collector for directing light to a concentrated area on a target surface such as for use with a linear LED array used as an erase lamp in an electrophotographic printer. The collector includes a compound cylinder lens supported by a pair of reflecting members. The reflecting members reflect light rays from the LED array to the cylinder lens. The cylinder lens includes a lower surface for capturing the reflected light rays and a tongue extending from the lower surface for capturing light rays directly from the LED array. The cylinder lens directs and concentrates the captured light rays in a narrow line on a target surface. A plurality of cross-ribs extend between the first and second reflecting members to specularly reflect light beams from the LED array.

Abstract: A low ink sensing system is combined with an ink cartridge detection system to enable a more efficient ink jet printer. An ink container which supplies ink to an associated printhead is modified by the incorporation of two light directing elements, in the preferred embodiment, a faceted prism and a roof mirror, into a transparent wall of the container housing. The cartridge, comprising the ink container and associated printhead, is mounted on a scan carriage. Periodically, the carriage is conveyed to a sensing station comprising a pair of light sources and a commonly used photosensor. A first light source is energized and a beam of light is directed to a location where the roof mirror, would be positioned if the cartridge is present. If the cartridge is absent, lack of a reflected return signal is sensed, indicating a cartridge has not been inserted. Print operation is halted until a cartridge is inserted.

Abstract: A low ink sensing system is combined with an ink cartridge detection system to enable a more efficient ink jet printer. An ink container which supplies ink to an associated printhead is modified by the incorporation of two light directing elements, in the preferred embodiment, a faceted prism and a roof mirror, into a transparent wall of the container housing. The cartridge, comprising the ink container and associated printhead, is mounted on a scan carriage. Periodically, the carriage is conveyed to a sensing station comprising a pair of light sources and a commonly used photosensor. A first light source is energized and a beam of light is directed to a location where the roof mirror, would be positioned if the cartridge is present. If the cartridge is absent, lack of a reflected return signal is sensed, indicating a cartridge has not been inserted. Print operation is halted until a cartridge is inserted.

Abstract: A windowed shutter on a micro-electro-mechanical system improves output current of a non-contacting electrostatic voltmeter. The output current is increased by increasing the area modulated by the micro-electro-mechanical shutter system and by increasing the speed of that modulation. The increase in the area modulated by the windowed shutter is in direct proportion to the number of windows used. Moreover, the speed of the modulation is increased by increasing the resonant frequency of the system. Less shutter mass increases the frequency thus increasing shutter movement over time.

Abstract: A light collector for directing light to a concentrated area on a target surface such as for use with a linear LED array used as an erase lamp in an electrophotographic printer. The collector includes a compound cylinder lens supported by a pair of reflecting members. The reflecting members reflect light rays from the LED array to the cylinder lens. The cylinder lens includes a lower surface for capturing the reflected light rays and a tongue extending from the lower surface for capturing light rays directly from the LED array. The cylinder lens directs and concentrates the captured light rays in a narrow line on a target surface.

Abstract: A low ink sensing system is combined with an ink cartridge detection system to enable a more efficient ink jet printer. An ink container which supplies ink to an associated printhead is modified by the incorporation of two light directing elements, in the preferred embodiment, a faceted prism and a roof mirror, into a transparent wall of the container housing. The cartridge, comprising the ink container and associated printhead, is mounted on a scan carriage. Periodically, the carriage is conveyed to a sensing station comprising a pair of light sources and a commonly used photosensor. A first light source is energized and a beam of light is directed to a location where the roof mirror, would be positioned if the cartridge is present. If the cartridge is absent, lack of a reflected return signal is sensed, indicating a cartridge has not been inserted. Print operation is halted until a cartridge is inserted.

Abstract: A sensor system for measuring physical properties of paper. The paper property sensor system includes a surface and a diaphragm opposed to each other. The small diaphragm includes a first pair and a second pair p-type piezoresistors. Each piezoresistor of the first pair has a longitudinal axis and is located perpendicular to and very close to one of the long edges of the diaphragm. Each piezoresistor of the second pair has a longitudinal axis and is located between and parallel to first pair of piezoresistors, and away from the short edges of the diaphragm. Coupling the first pair of piezoresistors with the second pair via a Wheatstone bridge produces a voltage representative of the shear force exerted by a sheet.

Abstract: A sensor detects the presence of opaque and transparent copy substrates in a substrate transporting path and includes an LED disposed near the transporting path for projecting light toward a reflector on the opposite side of the media transport path and a phototransistor located relative to the LED and reflector to receive light reflected from the reflector which is periodically interrupted by substrates within the transporting path to provide an output proportional to the light received from the LED via the reflector. The operating range of the phototransistor has a linear portion and a saturated portion. A control, electrically connected to the sensor, adjusts the phototransistor to maintain the output signal in the linear portion of the operating range. The sensor is tilted at an angle with respect to the horizontal of a copy substrate to be able to detect transparencies.

Abstract: A system for transporting a sheet of material including an actuator, a position sensing system, and a tactile sensor system. The actuator imparts a known force to a sheet, moving it through to the position sensing system, which measures the sheet velocity at various points. Afterward, the sheet moves through the tactile sensor system, which determines the coefficient of friction of the sheet. Given these quantities, a controller can determine the mass of the sheet, which can be used alter the performance of the sheet transport system.

Abstract: A device for diagnosing the condition of copy substrate sensors including a transparent test document supposing a plurality of stripes of predetermined optical density The stripes are arranged in descending optical density about a stripe of maximum density and a transporter conveys the test document into communication with the optical path of each sensor. Circuitry responds to the stripes of predetermined optical density to provide a timing pulse of response of each sensor to the test document. The timing pulse is a. digital step pulse identifying the range of optical sensitivity each sensor and the step pulse represents a given set of stripes that provide a detector signal exceeding a threshold value.

Abstract: A system for measuring the mass of a sheet of material including an actuator, a position sensing system, and a tactile sensor system. The actuator imparts a known force to a sheet, moving it through to the position sensing system, which measures the sheet velocity at various points. Afterward, the sheet moves through the tactile sensor system, which determines the coefficient of friction of the sheet. Given these quantities, a controller can determine the mass of the sheet, which can be used alter the performance of a reproductive machine. A second embodiment of the mass measuring system includes an actuator, a position sensing system, and a subsystem for eliminating friction. The actuator applies a force to a sheet to move it into and through the subsystem. The position sensing system incorporated in the subsystem senses the acceleration of the sheet. Given this quantity, a controller can determine the mass of the sheet.

Abstract: A maintenance system for an ink jet printer of the type having a full width array printhead has a movable carriage with a droplet sensor and a nozzle recovery device. As the carriage moves along the length of the printhead, each nozzle checked, one at a time, by the droplet sensor for the presence or absence of an ejected droplet and if the droplet has the correct directionality. Any problem nozzle is identified during a single traversal of the carriage across the printhead, and during a second traversal, the identified problem nozzles have a recovery operation performed on them such as being cleaned to remove any dried ink or other contaminating particles or being primed in the case of a clogged nozzle. The problem nozzles which have had a recovery operation performed on them and checked again by the droplet sensor is required for the entire array of nozzles, and ink is conserved since only predetermined nozzles are printed.

Abstract: An optical element uniformly distributes radiant energy on a target surface, such as for discharging an area of a photoreceptor in a xerographic printer, or for applying infrared energy to dry an ink-jet image. A cylinder lens collimates light beams from a light source and directs the collimated light beams to a preselected area on the target surface. First and second refractive portions, each attached to and extending parallel to the cylinder lens, totally internally reflect light beams from the light source and direct the light beams reflected therein to the target surface.

Abstract: An infrared densitometer which measures the diffuse component of reflectivity as marking particles are progressively deposited on a moving photoconductive belt. Collimated light rays are projected onto a test patch including the marking particles. The light rays reflected from the test patch are collected and directed onto a photodiode array. The photodiode array generates electrical signals proportional to the total flux and a diffuse component of the total flux of the reflected light rays. Circuitry compares the electrical signals and determines the difference to generate an electrical signal proportional to the specular component of the total flux of the reflected light rays. Additional circuitry adds the electrical signals proportional to the total flux and the diffuse component of the total flux of the reflected light rays and compares the result of the summed signal to the specular component to provide a total diffuse signal for controlling developed mass.

Abstract: A sensor having a shutter mounted upon a shaft for rotation within a housing in opposition to a light path between an LED and photodetector is described. A potion of the shaft extends outside the housing connected to an elongated arm. A runner secured to the elongated arm, engages a moving photosensitive surface and deviations of the edge position of the photosensitive surface rotate the shutter in relation to the light path between the LED and photodetector for tracking the edge position of the moving photosensitive surface by providing signals representing shutter position.