Abstract: In an ink jet recording apparatus including a carriage operative to move in scanning motion for printing characters and symbols on a printing surface and supporting thereon a single printing head having a plurality of ink jet nozzles or a plurality of printing heads each having a single ink jet nozzle, the printing surface is formed as a curved surface and the printing head or heads are constructed such that ink can be ejected radially with respect to the center of curvature of the curved printing surface. The vertical spacing between dots formed by ejected ink can be adjusted by moving the printing head or heads relative to the printing surface to thereby adjust the spacing between the printing surface and the printing head or heads, and the transverse spacing between the dots can be adjusted by adjusting the scanning speed of the printing head or heads or the ink ejecting timing.

Abstract: A first ultrasonic transducer is normally energized so that the ink jet normally emerging through a nozzle of an ink manifold containing the pressurized ink may break into an ink drop within a charge electrode and the charged ink drop may be deflected by a pair of deflection electrodes so as to travel toward a gutter. In response to the ink-placement signal a second ultrasonic transducer is de-energized when it has been energized in phase or in opposite phase with the first ultrasonic transducer when the second ultrasonic transducer has been de-energized so that the formation of each ink drop may occur outside of the charge electrode and the uncharged ink drop may travel to strike against a recording medium.

Abstract: Ink is fed to an ink jet printing head (12) from which it is ejected into a sheet of printing paper (19). A plurality of capacitive ultrasonic vibrators (29), (31) are provided inside the printing head (12) to atomize ink therein prior to ejection. The ultrasonic vibrators (29), (31) are connected in parallel with each other and also to an inductor (48) to constitute a resonant circuit. An electrical drive signal is applied to the resonant circuit, the frequency of the drive signal being equal to the resonant frequency of the resonant circuit.

Abstract: A charging phase control device for an ink jet recording device wherein the ink droplets are positively or negatively charged in the recording mode. In the charging phase detection mode an ink droplet charging electrode is so energized that more than two successive ink droplets may be negatively or positively charged and one or more ink droplets which immediately follow said more than two successive, negatively or positively charged ink droplets may be uncharged or positively or negatively charged. The negatively or positively charged ink droplets repel each other and attract the uncharged or positively or negatively charged ink droplets so that they coalesce into large ink droplets. Therefore the distance between an ink head and an ink droplet detection means may be reduced, the ink jet recording or printing device may be made compact in size and light in weight; and ink droplet charging phase may be detected and controlled with a higher degree of accuracy.

Abstract: A first ink tank (17) is attached to a movable ink jet printing head (12) for supplying ink thereto. A second ink tank (28) which is larger than the first ink tank (17) is fixedly mounted at an end of a carriage (19) which supports the printing head (12). After the printing head (12) prints a line, a print end signal causes a sensor (33) to sense the amount of ink in the first ink tank (17). If the amount is low the printing head (12) is moved so that a connector (31) of the first ink tank (17) mates with a connector (29) of the second ink tank (28) and ink is urged to flow from the second ink tank (28) to fill up the first ink tank (17). The amount of ink in the first ink tank (17) is again sensed and if it is still low, indicating that the amount of ink in the second ink tank (28) is also low, an annunciator (41) is energized to urge the apparatus operator to fill the second ink tank (28) with ink.

Abstract: First and second optical systems each comprise identical converging lenses which focus light images of an object onto identical photosensor arrays, the lenses being parallel. First and second mirrors reflect the light images from the respective lenses onto the respective arrays. The first mirror is fixed whereas the second mirror is rotatable. Where the second mirror is rotated to a position where the light images on the arrays are identical, the distance to the object is a function of the position of the second mirror which is predetermined by triangulation. As the second mirror is rotated through a predetermined range the arrays are strobed a predetermined number of times to produce analog signals having magnitudes corresponding to incident light. The respective analog signals are subtracted and the resulting difference signals compared with a previously minimum value. Each time the arrays are strobed a counter is incremented.