Abstract: In an ink jet system printer of the charge amplitude controlling type, when it is desired to charge a specific ink drop being formed, the amplitude of charge for the specific ink drops is increased in accordance with a total of field strength of electric fields due to the charge amplitude of the preceding ink drops, the charge of the thus increased amplitude being supplied to the specific ink drop to thereby alleviate any charge distortion.

Abstract: In ink jet system printers of the charge amplitude controlling type, it is required, to ensure stable printing, that ink drop separation (drop formation) is timed to be in agreement with the application of charging signals. To this end, there are provided phase detecting signals having a period which is an integral multiple of the period of the exciting signals for the ultra-sonic vibrator attached to a jet nozzle, and which phase detecting signals are of opposite polarity to the charging signals. Moreover, in the printing operation, there are provided phase detecting ink drops which are charged by the phase detecting signals, in addition to printing ink drops. After the charge amplitude on the phase detecting drops is sensed, the phase detecting signals are controlled in a manner that the charge amplitude on the phase detecting drops takes the maximum value at all times.

Abstract: A pair of rotary deflection electrodes are provided to confront with each other in an ink jet system printer in order to deflect charged ink droplets emitted from a nozzle as they pass through a high voltage electric field established therebetween. Cleaners are installed close to the rotary deflection electrodes at the position where the electric field established between the rotary deflection electrodes will not be disturbed by the cleaners in order to sweep the rotary deflection electrodes as they rotate.

Abstract: An ink jet system printer of the charge amplitude controlling type wherein a charge amplitude on ink drops charged by the application of phase detection signals to a charging electrode is sensed and then the relationship in phase between charging signals and ink drop separation is compensated in a manner to ensure that the ink drops are charged at an optimum state at all times. In the ink jet system there is provided a phase synchronization detection circuit for producing phase synchronization signals only when the phase relation is maintained at an optimum state due to the compensation, and a phase synchronization time period measuring circuit for determining whether the phase synchronization signals occur in sequence during a specified period of time and for producing printing ready signals if an affirmative answer is obtained.

Abstract: An ink jet system printer of the charge amplitude controlling type wherein a predetermined phase relationship is established between separation of ink drops from a nozzle to a record receiving member and application of charging signals to a charging electrode, through detection of the amplitude of charge carried on ink drops contributable to phase determination. Charging signals of one polarity containing intelligence signals are supplied to the charging electrode to charge ink drops contributable to printing, whereas phase detecting signals of the opposite polarity to that of the charging signals are supplied to the charging electrode for the purpose of charging ink drops contributable to phase determination. Both of the charging signals and the phase detecting signals are mixed in a mixer circuit arrangement of a simple construction which consists of a pair of switches, before both signals are supplied to the charging electrode.

Abstract: The size of patterns printed by an ink jet system printer including an ink liquid issuing nozzle, a charging electrode and deflection electrodes is temperature dependent. When the ink liquid temperature increases, viscosity of the ink liquid reduces and hence a flow rate of the ink liquid increases. This causes both mass and a flying rate of an ink droplet emitted from the nozzle to increase. Therefore, a deflection amount becomes smaller and hence the printed pattern size becomes smaller than that of ordinary desired. A temperature senser is provided on an ink conduit adjacent to the nozzle, for detecting the ink liquid temperature and generating detecting signals. A voltage level of video signals applied to the charging electrode or a voltage level applied to the deflection electrodes is varied in accordance with the detecting signals in order to stabilize the size of the printed pattern.

Abstract: It is essential for an ink jet system printer of the charge amplitude controlling type that an ink drop separation rhythm is in correct phase relation with respect to the application of charging signals. Detection of such phase relation may be achieved by forming phase detecting ink drops in addition to printing ink drops, charging these phase detection drops with phase detection signals and then measuring the amplitude of the charges on the individual drops. One approach to detecting the amplitude of charge on the phase detecting drops is to establish a panel shaped or strip shaped detection electrode adjacent the wake of the ink drops thereby enabling said detection by virtue of electrostatic induction.

Abstract: In an ink jet printer of charge amplitude controlling type wherein a carriage travelling in a horizontal direction and carrying a nozzle for issuing ink drops and a charge electrode for charging the ink drops by voltage corresponding information sought to be recorded is provided together with a pair of high voltage deflection plates, a pair of compensation electrodes are provided on the carriege to establish an electric field being at right angles to the direction of the electric field formed by the deflection plates and voltage to the compensation electrodes is adjustable thereby to control inclination of a printed pattern.