Abstract: The ink jet method and thermal copying method have been developed as the method of obtaining hard copies in colors from terminals of data systems such as a computer. This inventive thermal recording apparatus can produce copies of clear images without color blurs or mixtures on multi-color heat-sensitive recording materials having a color developing mechanism which allows color development in desired hues. This invention recording head is small in size and low in cost, achieving recording of clear images without color blur at a higher speed.

Abstract: A tray for a fluid-jet printing device for starting fluid-jet streams issuing from an orifice plate in a direction substantially perpendicular to the orifice plate. The tray includes an elongated box-like structure movable between various positions, including a sealing position below the orifice plate for drawing a vacuum through the orifice plate and facilitating flow of fluid from a plenum chamber above the orifice plate through the orifice plate for start-up. The tray is provided with backlighting such that, upon movement of the tray into a second position, the fluid streams issuing from the orifice plate may be visually observed against the backlighting to ensure proper start-up. Thereafter, the tray is moved to subsequent positions enabling location of the charging and deflection electrodes and droplet catcher structure below the orifice plate, as well as the substrate on which the printing will be effected.

Abstract: In accordance with a printing data, resistive thermo-generating elements in a thermal head are selectively heated to a relatively high temperature and a heat-fusible solid ink on an ink ribbon is thereby melted and the melted ink is transferred to a printing paper, thereby printing characters on a printing sheet. The printed characters can be erased by contacting to the printed portion of the printing sheet the ink ribbon heated by the thermal head to a relatively low temperature. In order to prevent the printing and erasing qualities from being deteriorated due to the change in the environmental temperature, the duration of current application to the resistive thermo-generating elements is compensated for individually for printing and erasing modes in response to the change in the environmental temperature.

Abstract: Uniform electrical heating of a circular, single crystal germanium window (18) uses its bulk resistance and pairs of electrodes (20) equally spaced about the window's periphery. The electrode pairs are sequentially switched at a rate high enough to avoid thermal switching transients.

Abstract: A thermal transfer printer employs a relatively small diameter platen roller 20 flanked by a pair of sprockets 3c which support endless timing belts 2. A clamp 7' for gripping the leading edge of a sheet 6 to be printed is mounted laterally across and between the belts. The attendantly small radius of curvature of the roller at the printing station prevents any contact by components and structure mounted to the reciprocable printing head 1.

Abstract: A control method for providing an acceptable motion window (range) that restricts high accelerations and velocities of an ink jet print head. The method provides two limited step ranges that are initiated dependent on the total distance that the print head is to be moved. If the distance is outside of the window range, a first step is used to bring the print head to a position which is a fixed second step from the final position. By limiting the print head's motion in each step range, the excitation of the fluid (ink) system is limited. With the first step completed, a second step range is used to drive the print head to the final position. If the initial distance is within the window range, the second step range is selected to drive the print head. The method is implemented with a computer program and print head position signals.

Abstract: A thermal head for a printer in accordance with the present invention comprises: a substrate (11); a heater layer (12) on the substrate; lead wires (13a and 13b) formed on the heater layer for supplying electric power to the heater layer; and a single protective layer (20) for protecting the heater layer and the lead wires by covering them, the protective layer including an oxide or a nitride.

Abstract: A flow rate control system is disclosed for measurement of ink flow through an ink jet system. The flow rate control system receives an error signal indicative of deviation of flow rate from a set value. The system includes proportional (P), integral (I) and derivative (D) control to generate a control signal based on the magnitude and sign of the error signal. The control signal is used to control the on-time of an ink make-up valve which adds make-up ink to the system as ink is needed to maintain satisfactory operation. In a preferred embodiment, the PID controller has noise reduction capability through the use of clippers and low pass filters. In addition, conditional summation may be employed to minimize "hunting" at low error signal levels.

Abstract: An orifice plate assembly for use in continuous ink jet printers includes a linear orifice plate having formed therein at least one linear array of orifices extending from a first end region to a second end region. The orifice plate has a main body portion which tapers gradually in thickness (t) along the length of the plate from the first end region to the second end region. The orifice plate is mounted so as to have an effective width (w) which tapers from the first to second end region. The relation t.div.w remains approximately constant along its length dimension.

Abstract: A method of and apparatus for controlling the velocity of a stream of droplets in a continuous ink jet printing system comprises controlling, from a system cabinet, the velocity of the stream expelled from the print head through a nozzle under pressure from a pressure source, in dependence upon a measured pressure of the ink in accordance with a predetermined relationship between the velocity and the pressure. On start up the system calibrates for the pressure differential P.sub.c due to the conduit length and the relative elevation of the print nozzle; and a determination of the ink viscosity in made at predetermined times. Thereafter the velocity is controlled in dependence upon a required pressure value P.sub.r in accordance with a stored look-up table, the required pressure value at any time being determined substantially by a given relationship.

Abstract: A method and apparatus of the present invention corrects the nonuniformity in the printing density between the printing elements of a thermal print head by first printing across a transparent receiver with each element of the head activated with equal inputs (flat field). The print transmittance values are read from the transparent receiver using, for example, a microdensitometer, and an adjustment factor for each heating element is computed and maintained in storage to be combined with the number of heating pulses assigned to each of the respective heating elements as they perform their normal printing function.

Abstract: The present invention provides a method for correcting the density nonuniformities that occur down the page of a thermally printed document by providing a correction component, representing heating pulses, to each thermal printing element as a function of the line on which the thermal printer is printing. The correction component is determined from the product of a correction factor times the logarithm of the total number of lines to be printed divided by the number of the line next to be printed. The correction factor is calculated from the average number of heat pulses to be applied across the head at any time, or as a compromise a single number may be selected.

Abstract: An improved drop stimulation system for a continuous ink jet printer includes a generally rectangular orifice plate with orifices along a central, longitudinal axis and transducer members coupled to longitudinal edge regions of the orifice plate, equidistantly from the central axis. The transducers are actuatable to flex the orifice plate alternately concave and convex about its central axis.

Abstract: A thermal head driver circuit is disclosed, which comprises a thermal head including a plurality of heat generation elements in an array, a shift register for storing image data including a plurality of bits for a plurality of heat generation elements, signal generation circuit for generating a print signal having a duration corresponding to image data for each of said heat generation elements held in said shift register, and driving circuit for energizing the heat generation elements of the thermal head according to the print signal. The shift register has parallel data input terminals, to which all of image data including a plurality of bits for each of said heat generation elements are fed at a time. Image data is supplied in a single transfer from an external device to the driver circuit.

Abstract: The relation between an input energy at a thermal head and recording density in a thermographical recording system varies inconveniently by the ambient temperature or the head temperature, and moreover, the slope of the relation varies by the temperatures. Therefore, even if the input energy at the thermal head alone is precisely and minutely controlled, it is heretofore difficult to obtain the desired recording density if the temperature fluctuates. Even if the temperature at the thermal head is detected by a temperature sensor, and compensation is made based on the detected temperature, it is still difficult to achieve recording of high quality because there inevitably arise a time lag between the detected temperature and the real temperature of a heating resistor which is recording images.

Abstract: A dual mode thermal printer has two modes of operation, i.e., a multi-color recording mode and a monochromatic recording mode. The thermal printer includes a thermal printhead provided with a plurality of resistor elements which are functionally divided into a plurality of blocks, each preferably having the same number of resistor elements. During the multi-color recording mode, the plurality of resistor elements are activated in accordance with image data on a block-by-block basis; whereas, during the monochromatic recording mode, at least two blocks of the plurality of resistor elements are activated at the same time.

Abstract: An improved performance ferromagnetic self-regulating heater. Constant alternating current is applied to a layered structure including at least one ferromagnetic layer. One or more layers of non-magnetic material is added to the ferromagnetic layer in such a way that the power factor of the heater is very significantly increased above its value in the absence of at least one of the layers. The alternating current flows through the different layers in varying quantities depending on layer composition, temperature and Curie point of the ferromagnetic layer. The structure generates heat by resistive heating as a function of the power applied. In one embodiment a single layer of non-magnetic, high-resistance material is in intimate electrical and thermal contact with one surface of the ferromagnetic material.

Abstract: A multiple print head for a continuous ink jet printer has its individual ink jets produced by an electrostatic field as an array of cusps along a straight edge to which the ink is continuously supplied. The straight edge is produced by folding an electrically conductive foil to give a surface less prone to corona discharges.

Abstract: A modular ink circulation system for effecting ink flow, in a continuous ink jet printer, from the ink reservoir to the print head and from the print head back to the reservoir. The system comprises, e.g.: (i) an ink supply module including pump, heater and filter that are removable from the printer as a unit; (ii) an ink return module including a pressure transducer, an ink defoaming reservoir and an ink flow-control solenoid that are removable from the printer as a unit; and (iii) a vacuum module including an air pump, an air pressure regulator and an ink collector reservoir that are removable from the printer as a unit.

Abstract: An inkjet printer is disclosed for printing on a moving web in which at least two rows of nozzles are arrayed on a nozzle plate such that they form an oblique angle with the direction of movement of the moving web. The drops to be printed are charged so that they are deflected so that vertically adjacent nozzles from each of the two rows print overlapping interlaced drops to form a single print row on the moving web. The nozzles in one row are slightly offset from direct vertical alignment with the nozzles in the second row, so that the charging pattern to be applied to the drops generated is highly simplified. Charging is accomplished by a charge plate having slots extending into the plate to a sufficient depth so that the plate may be moved into position after the streams have been started, and may be withdrawn from position before the ink drop streams are turned off.