Abstract: A toner mass sensor includes a piezoelectric crystal having a resonant frequency, an electrode on a first face of the crystal, an electrically conductive lead connecting the first face of the crystal to an electrical contact point in the vicinity of a second side of the crystal, and a casing closed at one end by the crystal with the first face of the crystal allowed to contact developer outside of the closed casing through the opening of the casing. The casing and crystal defines an interior which is sealed from developer in a development station, within which sealed interior the second face of the crystal is protected from contamination by developer. The electrode is wrapped around the edge of the crystal to be accessible from the second side of the crystal, and the electrode is a metal; preferably aluminum. The interior of the casing is closed by a base member which carries an electrical circuit.

Abstract: First and second toner images are created on a primary image member. The first toner image is transferred to an intermediate image member and then transferred back to the primary image member to combine the two images. Preferably, the intermediate image member is a light roller that is inarticulatable and maintained in contact with the primary image member which is preferably an endless belt with sufficient wrap to drive the intermediate image member with low pressure in the contact nip. Cleaning is effected by transferring residual toner back to an empty portion of the primary image member from where it may be cleaned off by a primary image member cleaning station. Intrack registration of the images is maintained by adjusting the time between flashes in creating the two images.

Abstract: A piezoelectric toner mass sensor to be positioned adjacent to a toner applicator in an electrostatographic recording apparatus. The piezoelectric sensor has a circular central crystal having its front and rear surfaces metallized, the two metallized surfaces being concentric with one another. The front surface of the sensor directed toward the toner applicator is smaller than the rear surface. Reducing the area of metallization on the piezoelectric toner mass sensor greatly increases sensitivity of the device. In addition, limiting the development area on the sensor facilitates the cleaning of the piezoelectric element and facilitates the mounting of the sensor in a suitable holder.

Abstract: The present invention constitutes in an ink jet printing apparatus, an improved ink replenishment system. An ink supply housing of the improved ink replenishment system includes a pair of opposed side walls having a plurality of attachments spaced in respective opposing vertical columns and detachable detents coupled to one of the attachments. An attachable ink supply conduit is associated an associated ink supply module includes a container of ink having an ink egress constructed to attach to the conduit, and a housing having bottom and side wall members supporting the container. The side walls have a vertical edge with a plurality of removable sections located in spaced relations corresponding to the column spacing of the attachments and sized to correspond to the detents. Only an ink supply module having proper sections removed can be moved into the housing to an extent sufficient for its egress to connect to the supply conduit.

Abstract: An apparatus for cleaning toner from a surface includes a scraper blade that removes toner particles from the surface. A storing container is provided for holding the removed toner particles. The toner particles are guided away from the surface by a guide member. The guide member is movable toward the storing container to move the removed toner particles to the storing container. In a preferred embodiment of the invention, the removed toner particles are compacted by the guide member. A cleaning implement is utilized to remove toner particles from the compacting member.

Abstract: Apparatus for removing toner particles from a film photoconductor used in copiers, printers, and other electrostatographic devices. A piezo film is wrapped around a pliable material which is positioned around a rigid tubular member. The ends of the piezo material are clamped to the tubular member by special clamps which allow the piezo film to expand and contract radially when excited by an alternating power source. The film is positioned against the inside of the photoconductor to impart an agitating or vibrating motion which accelerates and loosens toner particles from the other side of the film. A charged roller is spaced from the photoconductor and attracts the agitated toner to the roller for deposit in a collection hopper.

Abstract: A sheet stacking apparatus for receiving sheets from a printing or copying machine includes guide structure for directing output sheets onto an elevator platform and a selectively rotatable shaft having paddle arms disposed at a 108.degree. interval. The shaft rotation is controlled so that the arms guide a sheet during stacker input and then rotates 360.degree. to positively clear the sheet trail edge from the stacker input path.

Abstract: A hydraulic intensifier for oil well fracturing and/or erosion drilling, having a pair of intensifier units including a pair of sequentially operated reciprocating ram assemblies powered by hydraulic cylinder motors which are operated to maintain a substantially uniform output fluid pressure from the intensifier unit. Each cylinder motor is supplied from a main source of hydraulic fluid under high pressure which operates on the working faces of the pistons of the cylinder motors. Hydraulic fluid is also supplied to the return face side of each piston in the hydraulic cylinder motor.

Abstract: A quadraplex pumping unit for use as a mud pump, an intensifier, or as a pump for abrasive fluids or the like includes four rams and four ram operating pistons. A control valve arrangement provides for pressure equalization and energy transfer from a cylinder which has just extended in a working stroke to a companion cylinder which has just returned to its retracted to rest position, to conserve energy and reduce the thermal burden on the hydraulic system. The valve arrangement further provides for prepressurization, after pressure equalization, prior to an extending stroke.

Abstract: An intensifier unit includes a pair of sequentially operated reciprocating ram assemblies, each powered by a cylinder motor. Extension of the cylinder rods is accomplished by application of pressurized hydraulic fluid to the pistons. The pistons are returned quicker than they are extended by means of continuous application of pressurized air to the back side of the pistons. The cylinder motors are precompressed prior to their respective forward strokes by means of an accumulator which continuously bleeds from the main hydraulic fluid supply line. Circuitry is provided to insure that precompression continues even if the ram and its driving piston move from their retracted position. Also disclosed is a safety interlock to shut down the intensifier if both cylinder rods become accidentally simultaneously extended.

Abstract: A hydraulic intensifier for oil well fracturing and/or erosion drilling incorporates a pair of intensifier units mounted on a common bed. The intensifier units are particularly defined for ease of maintenance in the field, and structure is provided by which the ram seals as well as the ram, the ram cylinder, and the hydraulic cylinder can be easily and readily removed in the field without the necessity for releasing the tension on the tie rods. To this end, the apparatus includes a front wall which supports the ram cylinder and an intermediate wall which supports the forward end of the hydraulic cylinder. The space between these walls and the manner in which the components are assembled permits the ram seal assembly, the ram and ram cylinder, and hydraulic piston to be extracted and reinserted. Also, an improved ram return system and a hydraulic cushioning system are disclosed.