Oki Electric Industry Co., Ltd.

Oki Data Corporation

Toshiyuki Asaka

Hideaki Ishimizu

Hiroshi Kikuchi

Jiro Tanuma

Yoichi Umezawa

Mitsuru Kishimoto

Takao Uchida

Hirokazu Andou

Shigeru Tsunoda

Takanori Mimura

Toshiro Suemune

An apparatus for driving a printhead has a timer, a power supply, and a controller. The power supply applies a drive voltage to the printhead to eject ink drops from the printhead. The timer counts an elapsed time during which the printhead does not eject ink drops. The controller performs an ejection test where the drive voltage drives the printhead a plurality of times to eject a plurality of ink drops. The controller drives the power supply to increase the drive voltage in accordance with a length of the elapsed time. The ejection test is performed at a predetermined length of the elapsed time, the drive voltage and the predetermined length of the elapsed time are selected in accordance with a decrease in an ejection speed of the ink drops. The controller controls the drive voltage such that the surface of meniscus of ink in the orifice is subjected to fine vibration before the ink drop is ejected. The surface of the meniscus is subjected to fine vibration prior to either a printing operation or an ejection test. When the ejection test is performed, the controller determines the drive voltage by adding a first correction voltage to a drive voltage required for a printing operation. When the surface of meniscus is subjected to fine vibration, the controller determines the drive voltage by adding a second correction voltage to the drive voltage.

Apparatus for driving a printhead and method of driving the printhead

Resiliency of a flat spring 7 corresponding to an end print wire 12 is set to be greater than that corresponding to a central print wire 12 by varying width of an effective spring portion 7b of a flat spring piece 7A to which an armature 13 is attached depending on positions of corresponding tips of the print wires 12. Distance between a magnet yoke 5 and a core 15 provided between the flat spring 7 and a permanent magnet 4 at a position corresponding to a central print wire 12 side is set to be smaller than that at a position corresponding to an end print wire 12 side by varying it depending on positions of corresponding tips of the print wires 12.

Wire dot print head with print wires fixed to tip portions of armatures

A controller for a dot impact printer has capacitance sensors for sensing the motion of the dot wires in the print head, and a non-volatile, rewritable memory for storing self-adjustment data relating to dot-wire characteristics. A processor controls the driving of the dot wires according to the self-adjustment data stored in the memory. At certain times, the processor causes the dot wires to be driven in a test sequence and updates the self-adjustment data in the memory according to the resulting sensor output. Print quality is thereby maintained for the full guaranteed life of the print head.

Self-adjusting controller for dot impact printer

A wire-dot printing head having a plurality of printing elements each including an armature fixedly holding a printing wire on the free end thereof, a plate spring fixedly holding the armature on the free end thereof, a permanent magnet for attracting the armature to strain the plate spring so that strain energy is stored in the plate spring, and an electromagnet which cancels the magnetism of the permanent magnet when energized to release the armature so that the armature is returned to the free position thereof by the strain energy of the plate spring to advance the printing wire for printing. The plate spring has an operating lug portion which can be bent in either direction from outside, and an adjusting lug portion which is formed integrally with the operating lug portion and is moved in the opposite direction when the operating lug portion is moved in one direction to adjust the position of the base end of the armature so that the strain energy stored in the plate spring is varied.

Wire-dot printing head with adjustable spring force

An IC card connecting mechanism connects an IC card having a terminal array with a connector for connecting the IC card to external equipment. The IC card connecting mechanism includes a frame of the IC card, having a peripheral rim provided with recesses at opposite ends of the front portion thereof, a terminal protecting member of the IC card, having a terminal protecting part for protectively covering the terminal array, and legs extending from the opposite longitudinal sides of the terminal protecting part and held at respective free ends thereof on the frame of the IC card. A body of the connector has guide legs for guiding the IC card upon inserting the IC card in the connector. Lifting devices provided in the body of the connector enter the recesses of the frame to lift up the terminal protecting part of the terminal protecting member when the IC card is inserted in the connector. Thus, the terminal protecting part of the terminal protecting member is lifted up automatically to expose the terminal array for electrical connection with conductors of the connector when the IC card is inserted in the connector.

Growing community of inventors

Tokyo, Japan

Toshiyuki Asaka