Abstract: An ink jet printer serves to solve a problem that ink is not normally discharged when bubbles are present in ink contained in a ink chamber of a print head. The ink jet printer performs normal discharge of ink by detecting bubbles contained in ink and carrying out an optimum head recovery operation, so that stable and high-quality printed matter can be obtained. According to a bubble detecting circuit and method employed in this ink jet printer, the impedance of the piezoelectric element of the head is first measured at given frequencies. Then, impedance versus frequency characteristics are obtained. Subsequently, it is determined, based on the impedance versus frequency characteristics, whether or not a bubble adheres to the piezoelectric element.

Abstract: An ink jet recording apparatus of the shear mode type includes a recording head having a nozzle and, when a drive pulse signal is supplied thereto, driven to expel, from the nozzle, an ink supplied from an ink supply onto a recording medium so that recording is executed, a driver for supplying the pulse signal to the recording head, a temperature sensor for detecting an ambient temperature, and a control for changing the drive pulse signal corresponding to one record data on the basis of the ambient temperature detected by the temperature sensor.

Abstract: A plurality of recording heads for ejecting inks of different colors are reciprocally moved relative to a recording medium, and printing operations are performed by executing main scans in forward and backward scans of the recording heads. In this case, an area printable in a single main scan is recorded by performing a plurality of main scans using a plurality of thinning patterns in which an m×n pixel group is defined as a unit pixel group, and the pixel groups are arranged at non-neighboring positions, and which have a complementary arrangement relationship therebetween. A high-quality color image free from time difference nonuniformity, and density nonuniformity caused by, e.g., variations of recording elements is obtained at high speed.

Abstract: A cover for an alignment sensor that provides sensor output so as to align printer output from multiple print heads in an ink jet printer. The cover is preferably mounted for hinged movement between an open position and a closed position so that a sensing face of the alignment sensor is protected from ink mist during printing operations. A chassis of the printer may be provided with projections that engage with the cover when the carriage is moved to extreme rightward and leftward positions on the printer, so that the cover may be hinged to the open and closed position simply through movement of the printer carriage. Preferably, the cover is formed of an electrically conductive material with a tab that grounds the cover to a metallic portion of the printer chassis. Forming the cover from an electrically conductive material provides the additional benefit of protecting the alignment sensor from static discharge.

Abstract: While a pressure producing chamber is largely expanded before jetting ink droplets so as to increase an amount capable of capturing meniscus, distances of d1, d2, and d3 defined from the meniscus produced when the ink droplets are jetted up to a tip portion of a nozzle opening are arbitrarily varied in order to adjust the weights of the ink droplets. As a result, the ink amount of the ink droplets can be reduced which are jetted from an ink jet type recording head in which a piezoelectric vibrating element is employed as a pressure producing source.

Abstract: The present disclosure relates to an inkjet printing system for depositing ink on media. The inkjet printing system includes an ink containment vessel formed from a material having optical characteristics selected to block light in the visible light spectrum. Also included is an energy source for providing energy having characteristics that are selected to allow energy passage through the ink containment vessel. Finally, an energy detector is included for detecting energy provided by the energy source that passes through the ink containment vessel. Energy from the energy source impinging upon ink is altered so that an energy detector output signal is indicative of ink within of the ink containment vessel.

Abstract: When a reduction recording is made by using a portion of a plurality of recording elements and a test pattern is recorded, a recording element of one end of a recording element array is positioned next to a recording element of the other end. As a result, in a recording apparatus by using a recording head provided with a plurality of the recording elements, a suitable correction of shading is made in a reduction recording mode.

Abstract: A method and apparatus for optical determination of turn-on energy and operational printhead energy for ink-jet printing includes a computerized method for using reflectance readings from a test pattern generated by a printhead under test. The test pattern includes regions (|1|−|N|) generated by applying to the printhead ink drop generators firing pulses having a pulse energy substantially equal to a predetermined reference pulse energy at a predetermined pulse frequency starting with a pulse energy substantially equal to the predetermined reference energy and incrementally changing the pulse energy of the firing pulses such that firing pulses of increasing or decreasing pulse energies are sequentially applied to the drop generators.

Abstract: There is provided an ink-jet printer for jetting ink drops through nozzle holes in which each of the nozzle holes is circular in section, a ratio a/d of a nozzle hole roundness of each of the nozzle holes a to a nozzle hole diameter of each of the nozzle holes d is not more than 0.2, and an amount of ink/jet which is jetted through each of the nozzle holes is not more than 20 pl. According to this ink-jet printer, a good printing quality can be obtained without impact-errors.

Abstract: Apparatus and techniques are disclosed for aligning the operation of the ink jet printhead cartridges of a multiple printhead ink jet swath printer that includes a print carriage that is movable along a horizontal carriage scan axis, (b) first and second ink jet printhead cartridges supported by the movable carriage for printing onto a print media that is selectively movable along a vertical media scan axis, and (c) an optical sensor supported by the movable carriage. The optical sensor includes a quad photodiode detector whose outputs are indicative of the horizontal positions of vertical test lines imaged on the detector in conjunction with horizontal alignment correction, as well as the vertical positions of horizontal test lines imaged on the detector in conjunction with vertical alignment correction.

Abstract: In a print head of this invention, electricity-to-heat converters and a driver circuit for driving these electricity-to-heat converters in accordance with print data are formed on a single board. The board further includes an input/output interface circuit for receiving print data from an external apparatus, a CPU for controlling a printer apparatus, a ROM, a RAM, an A/D converter, a D/A converter, a timer, and the like, and also includes an external element driver for driving a mechanism portion of the printer apparatus.

Abstract: An ink-jet recording apparatus includes recording head having a plurality of recording elements and performs image recording by the steps of detecting a presence of black dots in a prescribed amount of input data and calculates a percentage of black dots, selecting a suitable recording mode for forming an image of the prescribed amount of input data on the recording medium in response to a result of the calculation, and controlling a drive condition of the recording head in accordance with the selected mode. When the percentage of the black dots exceeds a prescribed level, the recording head is driven so as to remove some dots from a total number of dots corresponding to the prescribed amount of the input data or reducing thermal energy to be supplied to the thermal elements in the cause of the image recording.

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 method and means for automatic alignment of ink-jet printheads includes fitting measuring constructs to actual print data acquired form a print made using a given, predetermined, test pattern data set. Specific test patterns for use in automated alignment of ink-jet printheads are suited to providing a variety of printhead alignment information in a compact format. The test pattern data set incorporates techniques for avoiding carriage-induced dynamic errors during automated alignment of ink-jet printheads.

Abstract: An image recording apparatus using a plurality of recording heads that can prevent black lines from occurring at boundaries of each scanning of the recording heads. The total recorded ink volume at the boundaries is positively reduced so that the black lines and the overflow of ink are prevented. The apparatus includes at least a pair of a dark head for discharging relatively dark ink and a light head for discharging relatively light ink, and separates an input image signal into image signals applied to the dark and light heads using at least two tables. The two tables, one for edge nozzles of each recording head and the other for the remaining nozzles, separate the input image signal independently so that the total ink volume discharged from the edge nozzles are limited to a relatively small amount.

Abstract: An image recording apparatus includes a recording unit integrally having an image forming recording head and a memory for storing a correction datum for correcting non-uniform image formation property; a reader for reading the correction datum from the memory; and a device for changing image forming conditions in accordance with the correction datum read by the reader. The apparatus also can alter the image forming conditions changed by the changing device when the non-uniformity of the recording unit changes.

Abstract: There have been desired a liquid discharge method, a liquid discharge head and a liquid discharge apparatus capable of sufficient temperature adjustment for maintaining the viscosity of the discharge liquid within an appropriate range, there by maintaining constantly stable liquid discharge. In this invention, the movable member provided with a heating member simultaneously or individually controls the temperatures of the liquid in the first liquid path and that in the second liquid path.

Abstract: In an ink jet recording apparatus, a plurality of kinds of heads are separately mounted and a waste ink container is provided. The ink level of the waste ink container is monitored, and the kind of ink jet head mounted is detected. The amount of waste ink exhausted from a mounted ink jet recording head is corrected in response to the kind of ink jet head mounted. Each kind of ink jet printhead mounted has distinct waste ink exhaust properties caused by factors such as different size of ink drops, or different number of printhead exhaust ports which affect preliminary discharge amounts of waste ink and factors such as different suction loads on the ink tanks, different flow resistances of the ink flow passages and different viscosities of the inks used in the printheads which affect suction recovery amounts of waste ink. The recovery function is corrected such that the waste ink amount exhausted from the mounted head is carried out in accordance with the mounted ink jet head.

Abstract: There is provided an ink-jet printer for jetting ink drops through nozzle holes in which each of the nozzle holes is circular in section, a ratio a/d of a nozzle hole roundness of each of the nozzle holes a to a nozzle hole diameter of each of the nozzle holes d is not more than 0.2, and an amount of ink/jet which is jetted through each of the nozzle holes is not more than 20 pl. According to this ink-jet printer, a good printing quality can be obtained without impact-errors.

Abstract: Continuous jetting of liquid metal droplets for deposit on a substrate includes an ejector, a deflection device, a print chute, and a collection reservoir. Liquid metal from a cartridge in the ejector provides a continuous molten material stream through an orifice-defining structure while a vibration device creates a standing wave in the stream to break the molten material stream into individual droplets which receive charge from a charging device. The deflection device enables the positioning of the charged droplets to be controlled for placement on a substrate. Control systems assist in the calibration and control of the continuous stream to ensure that selected droplets are placed at desired locations on the substrate.