Hitachi, Ltd.

Hitachi Seiko, Ltd.

Hitachi Koki Co., Ltd.

Other

Eiji Yoshino

Yasumasa Matsuda

Takahiro Yamada

Tatsuki Inuzuka

Takeshi Shibuya

Atsushi Onose

Masayuki Kanda

Tadashi Okada

Satoshi Namekawa

Akira Sasaki

Hitoshi Tamura

Toshiaki Nakamura

Nobuo Suzuki

Hiroyuki Tadokoro

Naoyuki Urata

Tatsunari Satoo

A personal computer has a print image developing means and a data compression means including a fixed rate compression. A color printer has a data extension means, a color correction means, a gamma correction means, a first halftoning means, an image area segmentation means, and a second halftoning means. The transmission time of a print image can be shortened necessarily to less than a constant time, and further, since an enormous memory for extension is unnecessary, a low cost printer can be provided.

Information print system and image processing apparatus

In a halftoning unit of a laser printer and the like, a high speed, high density and high gradations halftoning is realized by multi-value implementation by clustered dot concentrated dither halftoning (known as a sub-matrix method) and PWM distributing gradation among the plurality of halftone dots with a small memory and circuit. For this purpose, the value of the difference between an input gradation value n,and a threshold value n,, &Dgr;n&equals;n,&minus;n,, is shortened within a range of 0 to &Dgr;h and the lower s bit of &Dgr;h is removed by a round-down or round-up process. Meanwhile, a threshold array is generated from an extended threshold pattern obtained by combining threshold patterns of 2,whose threshold interval is &Dgr;h, i.e. &Dgr;Ah&times;K, &Dgr;h&times;K&plus;1, . . . , &Dgr;&times;K&plus;2,. Thereby, a halftone dot dither process in which the PWM gradation increases distributively among the 2,dots may be realized with a small scale memory and circuit.

Distributed PWM halftoning unit and printer

An original reading apparatus reads out an original which is laid with its surface to be read being directed upward, to thereby convert the read information into an image information. The original reading apparatus has a digitizer function so that a partial reading region of the original is assigned and read out after operator's confirmation by direct observation from an upper side of the surface to be read of the original. A transparent plate on which is depicted reference coordinates for showing a readable region of the apparatus is provided in the vicinity of the original, and a position of the original is finely adjusted on the basis of the reference coordinates. A reading sensor and a carriage mechanism of the original reading apparatus are received in a rotatable upper cover of the apparatus. In case of a large size original, the information thereof is read without any fold or cut of the original.

Apparatus for reading original

In an ink-jet recording device in which a nozzle is so excited that ink droplets jetted from the nozzle are alternately separated into large-diameter ink droplets and small-diameter ink droplets, and recording ink droplets to be stuck onto the recording surface are made to fly straight while nonrecording ink droplets are charged and deflected to be retrieved by a gutter, there are provided a nonrecording ink droplet sense circuit and a correction signal generator circuit for generating correction charging voltage when an ink droplet to be controlled is generated provided that the preceding ink droplet is a nonrecording ink droplet and the ink droplet to be controlled is a recording ink droplet.

Ink-jet recording device

An ink-jet printer including an ink jet nozzle for ejecting ink droplets onto the recording paper which is moved relative to the nozzle so that dots of ink are printed in the form of a pattern. The trajectory of flying ink droplets is deflected along the direction of the relative movement under control based on the measurement of the relative movement speed.

Ink-jet recording apparatus

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.

Growing community of inventors

Hitachi, Japan

Eiji Yoshino