Abstract: An ink jet printer has a plurality of ink ejection electrodes for receiving an ejecting voltage to eject an ink droplet, a pulse width generator for specifying the pulse width of each ejecting electrode to obtain a dot diameter of the ink droplet for gray-scale printing. The ejecting voltage Vej for each ejection electrode is divided into a plurality of unit pulses. Each unit pulse is supplied to a corresponding ejection electrode concurrently with unit pulses for other ejection electrodes. A combination of unit pulses for a single ejection electrode forms a single ink droplet having a dot diameter corresponding to the number of unit pulses, thereby achieving accurate gray-scale printing with a reduced circuit scale.

Abstract: An apparatus and a method for measuring the remanence curve of a magnetic material with high accuracy is disclosed. First and second pulse magnetic field coils generate a rapidly-changing pulse magnetic field in the space where a magnetic material is located. First and second air-core coils generate a space of a zero magnetic field as well as a finite magnetic field gradient around the magnetic material after application of a pulse magnetic field. A detector detects the force generated by the cooperation between the magnetic field gradient and the magnetic moment of the magnetic material. An arithmetic unit 33 determines the residual magnetization characteristic of the magnetic material based on the detection result in the detector.

Abstract: An inkjet device ensuring reliable and stable ink ejection is disclosed. A plurality of ejection electrodes are arranged in a housing having an ink chamber containing ink including toner particles and a gate electrode plate is placed at a predetermined distance from the ejection electrodes. The gate electrode plate has a slit formed such that the ejection electrodes are directed to the slit and an ink drain coupled to the slit for draining ink from the slit.

Abstract: An electrostatic ink jet printing head comprises printing electrodes formed on the base film of a substrate. The printing electrodes have insulating coating films which coat the printing electrodes, respectively. Each of the printing electrodes has a main electrode portion formed on the base film and a protruding electrode portion which protrudes from the base film. A covering member covers the main electrode portion. The covering member has an internal surface defining, in cooperation with the main electrode portions and the base film, a ink receiving space which receives ink containing toner particles.

Abstract: An inkjet recording apparatus includes an insulating support member having a major surface on which a plurality of ejection electrodes are formed with each of the ejection electrodes protruding from an ejection end of the insulating support member. Each of the ejection electrodes is coated with an insulating material. Further, a cover member is provided to cover the insulating support member to form ink chambers between them and an opening at an ejection end of the cover member. The ejection portion of each ejection electrode protrudes from the ejection end of the cover member through the opening. The ink is supplied from one ink chamber to the ejection electrodes and flows into the other ink chamber through the ejection electrodes.

Abstract: An electrostatic ink jet recorder of the type controlling charged toner particles contained in ink by using electrophoresis is disclosed. The recorder achieves a miniature and cost-effective configuration by reducing the number of drivers for driving ejection electrodes and auxiliary electrodes. The same amount of toner particles is ejected from all of ejection electrodes despite a scatter in the ejection electrode and a scatter in the position of the ejection electrode relative to auxiliary electrodes and a counter electrode.

Abstract: An electrostatic ink jet recording device includes a recording head having an ink chamber receiving therein liquid ink containing electrified toner particles and a plurality of recording electrodes for ejecting the toner particles from the liquid ink. Each of the recording electrodes is applied with a bias pulse train when the recording head resides in a printing area and a non-printing area, and a selected group of the recording electrodes are applied with a constant recording signal for ejection of toner particles. Undesirable ejection of the toner particles in the non-printing area is avoided by the application of the bias pulse train.

Abstract: Light of a light emitting portion is received by a total of two light receiving portions disposed opposite to each other through a record medium. The surface condition of the record medium is detected corresponding to the amount of light reflected and the amount of light transmitted so as to determine whether the record medium placed is plain paper, coated paper, OHP film, or the like. By controlling the number of heating elements of a heater or turning on/off the heater, an optimum fixing condition is accomplished.

Abstract: An ink jet recording head comprises a plurality of electrophoretic electrodes corresponding to a plurality of ejecting electrodes, and a pair of stirring electrodes disposed at both ends of the row of the ejecting electrodes. The stirring of the colored particles by the stirring electrodes prevents block of an ink jet slit by the concentrated colored particles, whereas individual control of the electrophoretic electrodes prevents undesirable ink ejection from non-specified ejecting electrode.

Abstract: The quantity of toner particles in an ink is detected by a toner quantity detector. The quantity of toner particles is integrated for a predetermined time period by a controlling portion. The integrated value is compared with a reference value. When the integrated value is smaller than the reference value, a value is opened for a predetermined time period so as to supply a toner in a toner replenisher to an ink tank. Thus, a predetermined quantity of the toner is replenished to the ink tank. After the toner has been replenished, when the integrated value does not become larger than the reference value, a valve is opened for a predetermined time period under the control of the controlling portion so as to replenish a charge control agent from a charge control agent replenisher to the ink tank.

Abstract: An ink jet recording device comprises a recording head for ejecting pigmented ink in an ink chamber, an ink reservoir for circulating the pigmented ink between the ink chamber and the ink reservoir, and a replenishment tank for replenishing concentrated pigmented ink to the ink reservoir. The replenishment of the concentrated pigmented ink is effected by a piezoelectric element for reducing the volume of the replenishment tank upon receiving a driving signal. The concentration of colored particles in the concentrated pigmented ink is equal to the concentration of the colored particles in the ink droplet ejected from the ink chamber.

Abstract: The electrostatic ink-jet recording head has a head member having a chamber for supplying and discharging ink, a head chip in which a plurality of continuous meniscus shapes are respectively formed on groove portions, a cover plate formed so as to expose a part of the corners of the groove and flange portions, and a protruded member on which pectinate protrusions are formed at the same intervals as those of the meniscus shapes formed on the head chip. A recording electrode is formed on each groove portion. Each protrusion of the protruded member is set on each groove portion of the head chip and moreover, formed so as to be protruded beyond the corner of the flange portion.

Abstract: An ink-jet printing apparatus, having (a) a plurality of ink-ejecting bars each having a pointed end, the pointed end being capable of moving toward a recording medium; (b) an ink reservoir for supplying to each of the ink-ejecting bars with ink including toner; (c) a counter electrode for drawing the toner in ink from a location faced to the pointed end of said ink-ejecting bar, said counter electrode and the ink ejecting bar interposing the recording member; and (d) recording electrodes for flying the toner in ink from the pointed end of each of the ink-ejecting bars.

Abstract: An electrostatic ink jet recorder of the present invention includes a head for ejecting ink, an ink reservoir storing the ink, and an ink feed pipe and an ink discharge pipe for circulating the ink between the head and the ink reservoir. The head has a first ink chamber communicated to the ink feed pipe, a second ink chamber communicated to the ink discharge pipe, a third ink chamber positioned at a higher level than the first and second ink chambers for ejecting the ink for printing, a siphon pipe communicating the first and third ink chamber and having a suction opening below an ink level in the first ink chamber, and an ink outlet pipe having an outlet opening above an ink level in the second ink chamber for delivering the ink from the third ink chamber to the second ink chamber. Delicate pressure variation in the head ascribable to the movement of the head is reduced in order to maintain pressure inside the third ink chamber for ejection stable.

Abstract: A precision ejection ink-jet printing apparatus to prevent self-ejection. Self-ejection is an ejection of coloring agent particles from an ink-ejection opening without an application of ejection voltage to an ejection electrode. The precision ejection ink-jet printing apparatus includes an ink chamber filled with a pigment type ink, an electrophoretic electrode for causing coloring agent particles in the pigment type ink to concentrate at ink ejection openings, a plurality of ejection electrodes for causing ejection of the coloring agent particles concentrated at the ink ejection openings toward a printing medium, and voltage controller for controlling a voltage to be applied to the electrophoretic electrode. The voltage controller gradually increases the applied voltage up to a predetermined target voltage. The gradual increase in voltage moderates the electrophoretic motion of the coloring agent particles, preventing self-ejection.

Abstract: An electrostatic ink-jet printing head in which ink containing charged toner particles in an insulating solvent is supplied from an ink reservoir, an electric field is applied to the ink to generate an electrostatic force, and the electrostatic force causes the toner particles to be ejected from ink ejecting ports. The electrostatic ink-jet printing head comprises a head block including a head block main body which defines an ink chamber and also including a base film which is assembled on the head block main body. The base film has ink ejecting ports and has a plurality of projections extending from one edge of the ejecting port into the ejecting port. The ejecting ports, ejecting electrodes and ejecting projections are collectively formed on a base film by a TAB technique, and by bending the base film at the ejecting ports having projections according to the shape of the head block main body.

Abstract: In an ink cartridge which is attached to a cartridge attaching part having a joint hollow needle, a case has a case internal surface which defines a receiving space and a front wall having a front wall internal surface which defines a first associating hole. A separating wall has a separating wall internal surface which defines a second associating hole which is associated with the receiving space. A first separating wall side surface of the separating wall and a first part of the case internal surface defines an ink receiving space which receives an ink. A second separating wall side surface of the separating wall and a second part of the case internal surface defines a leak ink accepting space. A joint film has elasticity and is formed on the separating wall internal surface to be positioned in the second associating hole. The joint film is able to be passed through by the joint hollow needle. A leak ink accepting member is positioned in the leak ink accepting space.

Abstract: An inkjet recording apparatus includes K ejection electrodes, M electrophoresis electrodes corresponding to M blocks into which the K ejection electrodes are divided, respectively, and an electrode opposite to the K ejection electrodes. A first voltage pulse is applied to a selected one of N groups each formed by electrically connecting an i.sup.th (1.ltoreq.i.ltoreq.N) ejection electrode for each block to each other. A second voltage pulse is applied to a selected one of the M electrophoresis electrodes. Ink ejection occurs at a desired ejection electrode specified by the selected group and the selected electrophoresis electrode in the case of a predetermined voltage applied to the electrode opposite to the K ejection electrodes.

Abstract: An electrostatic inkjet apparatus includes a plurality of ejection electrodes and a plurality of control electrodes. The ejection electrodes are arranged in an ink chamber for containing ink including particulate matter with protruding from a front end of the ink chamber. The control electrodes are arranged in the ink chamber such that each of the ejection electrodes is placed between two adjacent control electrodes. A voltage controller applies a control voltage to two control electrodes adjacent to a selected ejection electrode which is in a floating state and thereby a potential of the selected ejection electrode is changed to an ejection level.

Abstract: A record head for an electrostatic ink jet recorder includes a head chip implemented as a laminate of alternating flat conductors and flat insulators and etched by an etching liquid reactive only to the material of the insulators. The conductors readily turn out ridges protruding from the head chip and having a high aspect ratio. The ridges each serve as an ejection electrode.