Ricoh Company, Ltd.

Tamio Ohori

Satoru Tomita

Shuichi Karasawa

Mitsuru Kondo

Yutaka Ebi

Wasaburo Ohta

Osamu Naruse

Tatsuya Furukawa

Michio Umezawa

Fuyuhiko Matsumoto

Takeshi Kamada

Sadao Kakeno

Kazuyuki Hara

Noboru Furukawa

Isokazu Furukawa

Fuyuhiko Mastumoto

An ink ejection head including a nozzle holding member having an ink ejection nozzle threadably connected to a forward end portion of a liquid chamber structure. The ink ejection heads further includes a sealing member, such as a packing or an O-ring, located inwardly of a threaded connection as viewed from a liquid chamber in the liquid chamber structure. Introduction of dust or grit through the threaded connection into the liquid chamber can be effectively avoided by this arrangement, to thereby prevent obturation of the ink ejection nozzle.

Ink ejection head

A horizontal portion of an original document is scanned by means of N linear photosensor arrays arranged in a row. Each array has M photosensor elements. M strobe pulses are sequentially applied to the M photosensor elements of all of the arrays in parallel, the photosensor elements producing output signals in response to the respective strobe pulses. The output signals of the N photosensor arrays are applied in parallel to N printing electrode arrays for simultaneous printing, thus enabling high speed copying. The photosensor arrays are adapted to be strobed in sequence for facsimile transmission. A storage means is adapted to receive M.times.N facsimile input signals, divide the signals into N groups of M signals each and simultaneously feed the signal groups to the respective electrode arrays, the M individual signals of each group being fed to the respective electrode array serially. Alternatively, the groups of signals may be fed to the respective electrode groups sequentially rather than simultaneously.

Combination electrostatic copying machine and facsimile transceiver

In an electrostatographic apparatus (11) such as a facsimile receiver, an electrical discharge electrode assembly (14) progressively forms an electrostatic image on an endless belt (12) as the belt (12) moves relative thereto. The belt (12) comprises a transparent substrate layer (12a) on which is formed a photoconductive layer (12b) and a dielectric layer (12c), with the electrostatic image being formed on the dielectric layer (12c). A lamp (26) illuminates the photoconductive layer (12b) to vary the conductivity thereof with an intensity according to the speed of movement of the belt (12).

Variable speed electrostatographic apparatus

A sheet of copy paper (24) is moved perpendicular to a linear array (22) of printing electrodes (221, 222, 223, 224 . . . ). The electrodes (221, 222, 223, 224 . . . ) are selectively energized to form an electrostatic charge pattern on the copy sheet (24) corresponding to one horizontal scan line of an original document. The electrostatic charge pattern is developed by a toner and the resulting toner image fixed to the copy sheet (24). The electrodes (221, 222, 223, 224 . . . ) are divided into a first set (221, 223, 225 . . . ) and a second set (222, 224, 226 . . . ), the electrodes in the second set (222, 224, 226 . . . ) being alternatingly spaced from the electrodes in the first set (221, 223, 225 . . . ) along the length of the array (22). The first set (221, 223, 225 . . . ) of electrodes are selectively energized during a first time period (t1) and the second set (222, 224, 226 . . . ) of electrodes are selectively energized during a subsequent second time period (t2). The second time period (t2) may be made longer than the first time period (t1) and/or a voltage (V2) applied to the second set (222, 224, 226 . . . ) of electrodes may be made higher than a voltage (V1) applied to the first set (221, 223, 225 . . . ) of electrodes.

Electrostatic printing apparatus comprising improved electrode drive

Liquid or dry developing substance comprising charged particles is applied to a base electrode in the form of a rotary cylinder. A sheet of recording paper is fed in contact with the cylinder. A printing head comprises a plurality of printing electrode sets formed into an array such as a rectangular dot matrix in which each electrode set constitutes a row of the matrix. Each electrode set comprises a plurality of shaping electrodes which constitute the individual data points of the row. At least one bias electrode is provided for each electrode set. Row select wires are connected to the bias electrodes of the electrode sets respectively. Shaping electrode or column select wires are connected to the shaping electrodes of all of the electrode sets in such a manner that a particular column select wire is connected to the shaping electrodes of all of the electrode sets in a corresponding column. A high voltage of the same polarity as the charged particles applied to the bias electrodes causes the charged particles to be repelled against the surface of the cylinder and prevents printing. The voltage on the bias electrodes is lowered one row at a time to sequentially enable the rows for printing. The lower voltage also repels the charged particles against the surface of the cylinder but can be overcome by a higher voltage of a polarity opposite to the charged particles applied to the shaping electrodes of the selected row corresponding to the data points of the row which are to be printed. The interaction of the electric fields of the bias electrode and the shaping electrodes causes the attractive field of the shaping electrodes to be present only directly under the faces of the shaping electrodes thereby providing high printing resolution.

Improved electrostatic head with toner-repelling electrode

Liquid or dry developing substance comprising charged particles is applied to a base electrode in the form of a rotary cylinder. A sheet of recording paper is fed in contact with the cylinder. A printing head comprises at least one bias electrode to which is applied a bias voltage of a polarity to repel the charged particles against the cylinder. At least one shaping electrode which extends closer to the recording sheet than the bias electrode is selectively applied with a voltage of a polarity and magnitude to overcome the bias voltage and attract only the charged particles immediately adjacent to the shaping electrode to the recording sheet for printing.

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Tokyo, Japan

Tamio Ohori