Abstract: A head body is shaped to project toward an ink ejection side, and formed along the projection with an ink channel for circulating the ink, at the vertex of the front end of which an opening is formed for ejecting the ink from the ink channel. An ejection electrode is formed along the front end of the head body. Its front end reaches the opening. An electrophoresis electrode is secured in the ink channel at a position opposite to the opening, and supplied with a voltage for moving the toner particles in the ink flowing in the ink channel to the front end of the ejection electrode with the electrophoresis effect. An opposite electrode is positioned opposite to the ink ejection side.

Abstract: An electrostatic ink jet recording device has a bypass tube for circulation of the ink while bypassing the ink chamber, for obtaining a uniform concentration of toner in the ink. The recording device operates first in an ink stirring mode for stirring the ink in the ink reservoir for a uniform concentration of the toner, then in an ink replacement mode for replacing the ink in the ink chamber by the ink in the ink reservoir, and in a normal operation mode for effecting a normal recording of data.

Abstract: The invention relates to an ink-jet printer which uses an ink containing fine solid particles of a pigment suspended in a carrier liquid. The print head of the printer has an ink ejection orifice at one end of an ink chamber, and the ink chamber is provided with a first electrode to which a first DC voltage is applied for concentrating the pigment particles in the vicinity of the orifice by electrophoresis and a second electrode to which a second DC voltage in pulse form is applied for ejecting an agglomeration of the pigment particles together with a small amount of carrier liquid from the orifice. In the printer, the length of waiting time, which elapses from the decay of a pulse of the second voltage, is checked.

Abstract: An inkjet recording apparatus includes K ejection electrodes and M counter electrodes which are located at a distance from and opposed to the K ejection electrodes. A first voltage pulse is applied to a selected one of N groups of ejection electrodes each group formed by electrically connecting an i.sup.th (1.ltoreq.i.ltoreq.N) ejection electrode for each counter electrode to each other and a second voltage pulse is applied to a selected one of the M counter electrodes. A voltage difference is generated between a group and a counter electrode which are selected from the N groups and the M counter electrodes depending on an input signal, wherein the voltage difference is equal to or greater than a minimum voltage difference which causes ejection of ink from an ejection electrode.

Abstract: A control apparatus for controlling a concentration of a solute having a predetermined optical absorption characteristic is disclosed. A cell holding member has a plurality of cells formed therein, one of which is placed at a predetermined detection position so that the solution flows through that cell. A concentration of the solute is detected based on the intensity of light that has passed through the cell placed at the predetermined detection position. A cell changer replaces the cell with another cell by moving the cell holding member when a detected concentration has not changed as expected.

Abstract: An electrostatic ink jet according to the present invention includes a head body having an ink chamber for holding ink liquid containing charged particulate material; an ejection port provided at one end of that head body and connecting to the ink chamber; an ejection electrode arranged near this ejection port and fed with an ejection voltage of the same polarity as the charge characteristic of the charged particulate material; a counter electrode arranged opposite to the ejection port via a recording medium; and a pair of stirring electrodes. The stirring electrodes are arranged in the direction reverse to that of gravity in the ink chamber. The stirring electrodes are fed with a stirring voltage for shifting the charge particulate material in the direction reverse to the direction of gravity, and that stirring voltage is generated before the generation of the ejection voltage.

Abstract: In a small-sized, simple ink jet recording head achieves a high-quality and stable printing operation. The head includes an ejection cell for keeping therein ink including toner particles, a slit-shaped ink ejection slot disposed in a portion of the ejection cell, a electrophoresis electrode for concentrating the toner particles onto the ink ejection slot, an ejection electrode disposed in the ink ejection slot for imparting ejection force to the toner particles, and an ink stream path disposed in the ejection cell along a side wall of the ejection cell. The ink ejection slot is disposed in a portion of the side wall constituting the ink stream path.

Abstract: An ink jet recording head includes ejection electrodes arranged along ink paths that each have an ink outlet at one end and communicate with an ink chamber at the other end. The ejection electrodes are arranged in electrode sets, each set consisting of a number of ejection electrodes. The electrode sets have their corresponding ejection electrodes short-circuited, and are provided with control electrodes that are each common to respective ejection electrodes of a corresponding electrode set, and that are rearwardly offset from front ends of the ejection electrodes in an ink discharge direction. A voltage driver selectively imposes a voltage to groups of electrodes to provide a discharge biasing function, and selectively imposes a lower potential than a potential of the ejection electrodes to the control electrodes to provide a discharge restricting function.

Abstract: The invention relates to an ink-jet printer using an ink containing fine solid particles of a pigment suspended in a carrier liquid. The print head of the printer has an ink ejection orifice at one end of an ink chamber, and the ink chamber is provided with a first electrode to which a DC voltage is applied for concentrating the pigment particles in the ink in the vicinity of the orifice by electrophoresis and a second electrode to which a DC voltage in pulse form is applied for ejecting an agglomeration or several agglomerations of the concentrated pigment particles together with a small amount of carrier liquid from the orifice. The rate of migration of the pigment particles depends on the temperature of the ink. For stable ejection of agglomerations of pigment particles, a temperature sensor is disposed in the ink chamber, and the voltage applied to the first electrode is varied according to the detected temperature of the ink.

Abstract: An electrostatic ink jet recording device includes an ink chamber for storing therein a volume of ink containing charged toner particles, the ink chamber being provided with an ink outlet, an opposing electrode connected to a grounded node, the opposing electrode being arranged in opposition to the ink outlet with a sheet transfer route in between, a discharge electrode provided in a vicinity of the ink outlet for developing a first electric field between the discharge electrode and the opposing electrode to discharge a first quantity of charged toner particles as an ink jet, and an electrophoresis electrode for developing a second electric field between the electrophoresis electrode and the discharge electrode to have a second quantity of charged toner particles in the ink chamber migrate toward the ink outlet is provided an electric field control system is provided responsive to variations of the first and second quantities of toner particles to control a voltage signal imposed on the electrophoresis electr

Abstract: A system for monitoring the toner content in ink. The system comprising a light source and a photo-detector disposed in a ink chamber wall, a controller and a display unit. A content-monitoring voltage V1 and an operation-checking voltage V2 are determined from experiments in advance. V1 and V2 are such light source voltages when a predetermined current Ith is obtained from the photo-detector for the minimum and maximum allowable toner contents, respectively. In usual operation in user site, operation of the system is checked with the light source voltage set for V2 in response to a power-on or a reset. Then, a monitoring of the toner content is started with the light source voltage set for V1. In a toner content monitoring, the sensor current is checked to see if it is equal to or larger than Ith.

Abstract: An ink jet print head comprises a substrate formed with a heating resistor, an ink path defining member for defining an ink supply path, and a orifice plate, and in the orifice plate, there is formed an ink outlet at the position opposing the heating resistor. Further, a heating zone surrounding the heating resistor is formed at the position corresponding to the heating resistor of the ink supply path. The channel resistance of the ink supply path is set so that a relationship is established between a quantity q of the discharged ink drop, a sectional area A of the ink outlet, and a maximal projection h that a meniscus of the ink has when it projects from the ink outlet after it has restored the exit level from a retreat position it had after the drop of the ink had been discharged, such that 0<h<0.3q/A. Consequently, there is obtained a high-speed printing of high quality without dispersion.

Abstract: An electrostatic ink jet recording apparatus has a head body having an ink chamber in which ink charged to a specified polarity is stored, a plurality of ink ejection ports and a plurality of ejection electrodes. An ejection electrode drive circuit generates an ejection voltage to drive the plurality of ejection electrodes according to a time division method so that the ejection voltage is not simultaneously supplied to the adjacent ejection electrodes. A plurality of opposite electrodes are opposed to the plurality of ejection electrodes via recording paper. They are separated into first opposite electrodes corresponding to those ejection electrodes which are selectively being driven according to the time division method and second opposite electrodes corresponding to those ejection electrodes which are not being driven according to the time division method.

Abstract: An electrostatic ink jet record head of the present invention includes an ink chamber storing ink consisting of a carrier liquid and charged toner particles dispersed therein. An ejection port communicates the ink chamber to the outside of the head. An ejection electrode is disposed in the ejection port and electrically insulated from the ink. An electrophoresis electrode is positioned at the opposite side to the ejection electrode with respect to the ink chamber and electrically insulated from the ink. A control electrode is provided between the electrophoresis electrode and the ejection electrode and contacts the ink. Also, an electrostatic ink jet recorder of the present invention has, in addition to the head, a counter electrode facing the ejection port with the intermediary of a recording medium, and voltage controller for applying a particular preselected voltage to each of the discharge electrode, electrophoresis electrode, and control electrode.

Abstract: An ink jet print head using an electrostatic field and being capable of printing characters and letters with a high precision includes an ink chamber for keeping therein ink including charged toner particles, an ejection opening for establishing connection between the ink chamber and an external space, an ejection electrode arranged to be slightly projected from the ejection opening, a cataphoresis electrode disposed on a side opposing to the ejection opening of the ink chamber, an opposing electrode arranged to oppose the ejection electrode with a recording media therebetween, a cataphoresis voltage source for applying a predetermined voltage to the cataphoresis electrode, and an ejection voltage source for applying a predetermined pulse voltage to the ejection electrode. The ejection electrode is coated with a hydropholic insulating resin.

Abstract: In an ink jet type head assembly, a plurality of auxiliary electrodes alternate with a plurality of ejection electrodes. A voltage of the same polarity as charge deposited on toner particles is applied to two of the auxiliary electrodes adjoining an ejection electrode which should eject ink. This successfully prevents the toner particles from migrating toward the auxiliary electrodes away from the ejection electrode.

Abstract: An ink jet type head has a plurality of ink ejection electrodes in a form of parallel strips formed on a base. The ink ejection electrodes include first ejection electrode and second ejection electrodes provided adjacent to two sides of the first ejection electrode. There is provided a voltage driving unit for applying an ejection voltage for ink ejection to the first ejection electrode. In the voltage driving unit, the ejection voltage to cause the ink to be ejected is applied to the first ejection electrode and an auxiliary voltage ineffective to cause the ink to be ejected is applied to the second ejection electrodes. This enables the reduction of potential differences between the first and second ejection electrodes, thus suppressing movement of color particles of the ink between them.