Hitachi, Ltd.

Hitachi Koki Co., Ltd.

Hitachi Seiko, Ltd.

Satoshi Namekawa

Takahiro Yamada

Yasumasa Matsuda

Eiji Yoshino

While the excitation voltage of an ink jet nozzle is swept on the logarithmic scale, the generation state of ink droplets at a phase .theta..sub.k is examined. An excitation voltage value Vn generating an ink droplet of small diameter at the phase .theta..sub.k, an excitation voltage value Vn generating an ink droplet of large diameter at the phase .theta..sub.k, which is lower than vn, and an excitation voltage value Vn+1 generating an ink droplet of large diameter at the phase .theta..sub.k, which is higher than vn are stored. Difference values expressed as

Ink jet recording apparatus

In an ink jet recording apparatus, an amplification-degree control circuit is associated with an amplifier circuit amplifying a detection signal indicative of the quantity of charge of charged ink droplets, so as to decrease the degree of signal amplification by the amplifier circuit when a charging signal is applied to a charging electrode charging the ink droplets, but to increase the degree of signal amplification by the amplifier circuit when the quantity of charge of the charged ink droplets is detected from the detection signal.

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Ebina, Japan

Satoshi Namekawa