Abstract: A high resolution ink jet printing system includes a plurality of substantially identical print/cartridges each having an orifice plate comprising: (i) an array of orifices located in a precisely interspaced relation and (ii) a detent means precisely located with respect to the orifice array. The system provides a carriage for insertably supporting such print/cartridges and for traversing them along a linear print zone in a direction substantially perpendicular to the direction of print medium feed. The carriage has reference surfaces for respectively positioning the detent means of inserted print/cartridges at predetermined locations that are precisely vertically offset relative to the direction of carriage traverse. In such system the printing droplets from the vertically offset orifice arrays of inserted and indexed print/cartridges will be vertically interlaced in each printing traverse of the carriage.

Abstract: A system for printing with a plurality of removable print/cartridges includes a carriage constructed to traverse a linear print zone and removably support such print/cartridges. A plurality of referencing surfaces are located respectively on each of the carriages, parallel to the direction of the carriages traverse. The carriage includes fastening mechanisms for moving supported print/cartridges into a precise detent relation with respective referencing surfaces of the carriages. The referencing surface portions of the system are adjustable to allow selective physical indexing of print/cartridges, either in registered or interlaced printing positions. A transverse location detection system detects and stores the relative transverse locations of the print/cartridges in either position so that print control electronics can coordinate the output of the print/cartridges transversely.

Abstract: A linear light valve array having transversely driven, discretely addressable, electro-optic gates which selectively change the polarization of incident light is disclosed. The array has a plurality of spaced gates. Each gate includes a planar light receiving top surface which receives incident polarized light, and first and second spaced parallel electrode receiving surfaces that are arranged substantially normal to the top receiving surface. Discretely addressable electrodes are formed on such receiving surfaces. In response to an applied voltage, the electrodes of a gate establish a transverse electric field which changes the plane of polarization of light passing through the gate and substrate. In another aspect of this invention, a method of making such a linear light valve array is disclosed. In accordance with this method, a strip of photoresist material is formed on a wafer of electro-optic material. Grooves are then cut in the wafer on each side of the strip.

Abstract: A novel C-centered monoclinic bromoindium phthalocyanine pigment is obtained by reacting high-purity diiminoisoindoline with indium tribromide in the solvent, 1-methyl-2-pyrrolidinone. Multiactive photoconductive elements prepared by dispersion-coating a charge-generation layer containing this pigment have high sensitivity to near-infrared radiation.

Abstract: The detection system includes a cartridge having a first detection port for detecting the pressure condition in the top portion of the cartridge and a second detection port and tube for detecting the pressure condition in a bottom portion of the cartridge. The cooperative printer structure couples these ports to a pressure differential sensor that signals a printer refill condition.

Abstract: An ink jet printing apparatus includes elements for capillary support of ink in a region adjacent the orifice plate and lower print head structure and elements for selectively enclosing that region from the atmosphere. Elements for selectively removing ink from the capillary support region are provided.

Abstract: Ink jet printing apparatus having an improved system for start-up or maintenance includes elements for adjusting ink flow to impact on lower print head structure and elements for thereafter air skiving the ink from that structure.

Abstract: The performance of ink jet printing apparatus is markedly improved by heating critical lower print head surfaces, e.g. the exposed charge plate and catcher surfaces, to a temperature sufficiently above the ink temperature to prevent vapor condensation on those surfaces.

Abstract: In a continuous ink jet printing apparatus, an ink circulating system allows maintenance of the ink supply reservoir at approximately atmospheric pressure while providing for positive withdrawal of ink from the catcher and/or print head outlet of the apparatus. The system is operable with a single pump. To achieve such positive withdrawal of ink, elements are provided in a bypass line extending from the supply pump outlet to the atmospheric region of the ink reservoir or in the passage from that region of the ink reservoir to the pump intake line, for generating a region(s) of sub-atmospheric pressure, and such region(s) are coupled to the catcher and/or print head outlet.

Abstract: An ink cartridge constructed for insertion into a continuous ink jet printer, includes a reservoir for containing an ink supply, an outlet for coupling the ink reservoir to a printer supply line, cartridge venturi elements having (i) a restriction region, (ii) an expansion region and (iii) an inlet for detachable coupling to an ink bypass line of such printer. The cartridge also includes an ink return inlet couplable to an ink return line(s) of the printer and a path defining an ink induction passage that extends from the venturi restriction region to the ink return inlet. Structural features of printer apparatus, adapted to cooperate with such a cartridge, are also disclosed.

Abstract: Electrographic development is obtained by predeterminedly rotating an alternating pole core of a magnetic brush applicator, within a surrounding applicator shell, to supply developer, of the kind including small particle, hard-magnetic carrier and electrically insulative toner, to an electrostatic imaging member which moves past a development station with predetermined linear velocity. The shell can be stationary or rotate at a velocity significantly less than the image member velocity. The core is predeterminedly rotated so that (i) its fields effect a large portion of transport through the development zone and (ii) the developer moves co-currently with the imaging member and at a linear velocity generally equal to the imaging member velocity.

Abstract: Ink jet printing apparatus having a cleaning system whereby ink is supported proximate the droplet orifices, the charge plate and/or the operative catcher surface and ultrasonic cleaning vibrations are imposed on the supported ink mass. Such cleaning can be implemented with ink cross-flowing through the print head cavity and/or in cooperation with a varying pressure differential across the charge plate, which cause ink to oscillate inwardly/outwardly within the orifices.

Abstract: A cleaning system for ink jet printing orifices includes cooperative elements which provide varying pressure differentials across the orifice plate that oscillate ink into and out of the orifices. In one embodiment the pressure differentials are implemented by varying the impedance to ink cross-flow through a print head cavity while pressurizing a region around the exterior of the orifices.

Abstract: A home station of an ink jet printing apparatus is adapted to seal operative print head portions from the ambient atmosphere for storage and includes (i) a housing for collecting ink from the print head, during start-up and testing operations, (ii) a sensor for receiving ink droplets and detecting their charge condition and (iii) a fluid handling configuration that electrically decouples the ink in contact with the sensor from ink being returned from the housing for recirculation.

Abstract: An ink circulation system for continuous ink jet printers includes a replaceable ink cartridge, forming a supply/return reservoir, and cooperative positioning and interconnection structure of the printer apparatus. The cartridge includes valved ports that are adapted to cooperate with valved terminals of the printer conduits in a manner obviating ink spillage. The system provides cooperative positioning and engagement structures of the cartridge and printer, which simplify cartridge insertion and removal.

Abstract: A system for cleaning lower print head structure of ink jet printing apparatus effects: (i) a condensation cycle wherein a droplet stream(s) are directed past such print head structure in a solvent condensing mode, (ii) a drying cycle in which air is directed across said print head structure to remove condensed solvent and (ii) a heating cycle wherein the lower print head structure is heated to a temperature obviating condensation of solvent from said stream(s).

Abstract: To protect critical operative portions (e.g. the orifice plate) of ink jet printing apparatus from airborne debris particles (e.g. paper dust), a wall is provided to substantially enclose a region around those critical operative portions and filtered air is induced to flow through the enclosed region from a location proximate the operative portions to a droplet outlet. In one mode the energy of printing droplet streams induces the air flow. In another embodiment the energy of printing substrate movement induces the air flow.

Abstract: A device for coupling the conductive layer of a film-type photoconductor sheet to a source of reference potential includes a plurality of sharp, vitreous carbon particles which are attached to an engaging member and electrically coupled to a source of reference potential, e.g. ground. The engaging member is adapted to urge the particles to penetrate the photoconductive insulator layer and form a low resistance, ohmic contact with the conductive layer of the photoconductor sheet.

Abstract: Method and apparatus for electrophotographically producing high quality reproductions which contain different content types. Photoconductor image sectors are subjected to separate, component exposures selected for (1) good tone-scale reproduction of continuous-tone image portions and (2) high-contrast reproduction of line-type image portions. Photoconductor background areas, which border continuous-tone image portions, are exposed to a discharge level below the system's development level.

Abstract: Contrast and/or density adjustment of developed electrographic images is effected in a development system comprising a hard magnetic carrier and a magnetic brush having a rotary core and shell. The adjustment is effected by cooperatively varying the core and shell rotation rates, within predetermined ranges, in a manner which maintains the operative developer linear velocity generally equal to, and co-current with, the velocity of an electrographic image member's movement through the development zone.