Abstract: A method, apparatus, and article of manufacture for configuring a first printer to print according to the grayscale printing characteristics of a second printer is described. The method comprises the steps of characterizing the grayscale printing characteristics of the first printer and the second printer, defining a transform between the grayscale printing characteristics of the first printer and of the second printer, and modifying the first printer threshold matrix in accordance with the transform. The article of manufacture comprises a computer-readable medium tangibly embodying the above described method steps. The apparatus comprises a scanner or densitometer for characterizing the grayscale printing characteristics of the first printer and the second printer, a processor for determining a transform between the grayscale printing characteristics of the first printer and those of the second printer, and for modifying the first printer threshold matrix in accordance with the transform.

Abstract: A method of generating artifact-free threshold matrices for digital printing devices is provided. The method includes, for example, the steps of establishing a threshold matrix by examining at least one color level for artifacts and removing the color level from the threshold matrix if it has artifacts. The method further includes the steps of examining a range of color levels for artifacts and removing the color levels from the threshold matrix which have artifacts and evenly distributing the remaining color levels over a range of color levels from a first color level to a last color. The examination of color levels for artifacts may be implemented manually or through an automated computer controlled process. The automated process includes digitally acquiring the color level and performing a Fourier transform on the color level to determine its spectral components. The spectral components are analyzed to determine the presence or absence of artifacts.

Abstract: An electrophotographic apparatus and method are provided to reduce smearing on printed medium by reducing the toner pile height of printed lines and characters. Control is provided for establishing the amount of toner to be applied on a picture element (PEL) basis. This is accomplished by the creation of mask patterns that distinguish characters and lines from large patches to be printed, and by identifying PELs internal of characters boundary requiring exposure modulation during printing.

Abstract: A paper stacker includes adjustable sides to receive paper passively of different widths. The uppermost ends of the sides are flared to avoid paper encountering these ends, permitting the received paper to slide down between the sides to settle on a bottom surface without assistance. Each of the sides has a portion cut away to permit grasping a paper stack for removal. A trapezoidal platform is located on the bottom between the sides and has a friction material on a substantially flat upper surface to prevent paper slippage.

Abstract: An impact printing device for printing postal bar code patterns on an information carrier. The patterns are a combination of parallel tall and short bars separated by spaces. The type elements are attached to a movable type carrier, each element comprised of pairs of vertical bars having different stroke lengths but equal widths. Additionally these elements contain overscored and/or underscored horizontal bars, that when printed appear outside the postal bar code clear space. This produces print elements that have nearly equal area and in turn produce printed characters of uniform stroke widths that are easily read by the U.S. Postal Service electronic readers.

Abstract: An impact printing device for printing bar code patterns on an information carrier, the patterns including a combination of parallel thin and wide bars separated by spaces wherein the wide bars can have an imprint width which is a multiple of the thin bars, comprising a movable type carrier, a plurality of bar code type elements on said type carrier, the bar code type elements including first type elements having a pair of imprint forming parallel thin bars and second type elements having a single imprint forming thick bar, and a plurality of print hammers each defining a print position of a print line and each operable selectively to successively impact combinations of the first and second type elements at the same print position to form completed bar code imprints at the print position having a wide bar imprint with a width greater than the single thick bars of the second type elements.

Abstract: A platen assembly for an impact printer comprises the combination of an impact transducer between the backup plate and the type band of a printer and an impact isolator interposed between the transducer and the type band. The transducer comprises a strip of force sensitive material. The strip extends over a plurality of print positions. Electrode means in contact with the surfaces of the force sensitive material form discrete impact zones aligned with the print hammers. One of the electrode means is a continuous conductive strip on one side of the force sensitive strip. Plural conductive pads on the other side of the strip form the discrete impact zones. The continuous conductive strip is preferably on the side facing the type band and serves as the ground connection. The impact isolation means comprises plural force elements between the type band and the transducer element and preferably is part of a comb which can be conductive and provides stiffening to the force sensitive strip.

Abstract: A printer for printing both standard pitch and condensed pitch characters which includes print hammer faces which have a single wide section for standard pitch characters and a double wide section for printing condensed pitch characters. Using this hammer face one obtains the advantage of high speed when printing standard pitch characters and yet one is able to print condensed pitch characters with the same printer.The face of each hammer is divided into two sections. The first section of each hammer face is identical to the hammer face in a conventional single width hammer. The second section of each hammer face spans the width of two condensed pitch characters.The hammers are divided into two groups. The first group of hammers has the single width section on the top of the hammer face and the second group of hammers has the single width section on the bottom of the hammer face.

Abstract: A heat exchange system for an electromagnetically operated print hammer of a print hammer bank provides internal and external heat transfer for the operating windings. A non-magnetic metal bobbin of the heat exchange system provides conductive transfer of heat from the interior of the operating winding to the magnetic core. Flat parallel plates of magnetic material are attached to the sides of the operating winding for external heat transfer and magnetic flux shielding. The plates may have multiple laminations having different saturation and permeability characteristics.

Abstract: An electro-magnetic print hammer comprises a single magnetic hammer element in which an impact mass is coupled to a pivotted armature by flexible stem. The hammer-stem has (N+1/2) periods of oscillation at its resonant frequency during the free flight time of the hammer mass. A permanent magnet with a strong magnetic force which decays rapidly with distance holds the hammer element fixed upon motion of the armature until the armature torque exceeds the magnet holding force to cause the hammer mass to break loose with a snap action. Stop means prevents armature impacts with the operating pole piece of a stator core. The visco-elasticity of the armature stop matches the rebound characteristics of the print medium when impacted by the hammer mass.

Abstract: In an ink jet recorder, a ferrofluid ink is supplied under pressure to a nozzle to form a continuous ink jet stream. The jet stream is subjected to two or more perturbation forces out-of-phase with each other causing the satellites and drops to fast merge. Plural electromagnetic transducers are located at spaced locations along the stream and energized to produce out-of-phase perturbations on the stream. The spacing of the transducers is differentially related to spacing of varicosities or ink drops produced by first transducer. The out-of-phase perturbations can also be obtained using an electromechanical transducer and electromagnetic transducers located out-of-phase or energized out-of-phase with each other.