Oki Electric Industry Co., Ltd.

Oki Data Corporation

Katsuya Kamimura

Tatsuya Koyama

Hirokazu Andou

Tetsuhiro Yamada

Hiroshi Kikuchi

Jiro Tanuma

Tatsuhiko Shimomura

Norio Nakajima

Hirokazu Ando

Kiyoshi Ikeda

Masahiro Tatsukami

Yoshihisa Aikoh

Hisashi Tsukagoshi

Compensation data for use in driving an array of printing elements in a printing head are obtained by measuring the uncompensated output value of each printing element, calculating a target value for each printing element, and determining a compensation value from the difference between the measured output value and the target value. The target values vary continuously across the array. The compensation data are stored in a non-volatile memory in the printing head. During printing, each printing element is driven with an energy corresponding to the compensation data, so that the output profile of the array follows the profile of target values.

Method of compensating for output variations in a printing head

An LED head includes a circuit board and a plurality of LED arrays aligned on the circuit board in a longitudinal direction of the circuit board. Each of the plurality of LED arrays includes a row of a plurality of first LEDs aligned in the longitudinal direction between a second LED and a third LED. The second and third LEDs are at the end of the row. The first LEDs have a width W1 in the longitudinal direction and the second LED and the third LED have a width W2 in the longitudinal direction. The width W2 is smaller than a width W1. The first, second, and third LEDs have the same dimension D in a direction perpendicular to the longitudinal direction. The first, second, and, third LEDs are aligned at predetermined intervals P1 and the plurality of LED arrays are aligned such that the first, second, and third LEDs are aligned in the predetermined intervals P1.

LED head

The present invention is a light emission intensity width compensating method of an optical print head having a large number of light emitting devices, comprising the steps of measuring a light emission intensity distribution of each of the light emitting devices of the optical print head, slicing the distribution corresponding to a reference light emission intensity value, calculating a light emission intensity width of the reference light emission intensity value for each of the light emitting devices, designating a compensation value of drive energy so that each of the light emission intensity widths becomes equal, and causing each light emitting device to emit light corresponding to the compensation value of the drive energy. In addition, the present invention is an apparatus corresponding to the light emission intensity compensating method. The compensation values of the drive energy are stored in a storing means of the apparatus. When data is printed, the light emitting devices of the optical print head are lit corresponding to the compensation value of the drive energy. Thus, the drive energy is varied corresponding to the light emission intensity width. Consequently, a dot image can be printed free of uneven density.

Light emission intensity width compensating method of LED print head and

Wire driving mechanism

In a wire dot print head, swinging members are formed of plate springs and armatures, which are attracted toward a core to resiliently deform a plate spring when an associated coil is not energized, and are released and moved forward when the coil is energized. The swinging members are swung about the forward tip ends of fulcrum members. A partition sheet is interposed between the rear surfaces of the swinging members and both the front ends of the cores and the front tip ends of the fulcrum members to interrupt transfer of grease, and to prevent direct contact of the cores and the fulcrum members with the armatures. The partition sheet includes a front plastic film, a metallic residual sheet, and a rear plastic film which are stacked in the stated order from the front side to the rear side of the print head. The front film is bonded to the metallic residual sheet over the entire surface of the metallic residual sheet. By bonding the front film and the metallic residual sheet, migration of the grease from the rear side to the front side of the partition sheet is prevented, and adhesion of the grease to the plate springs is also prevented. Moreover, because of the bonding, the metallic residual sheet is prevented from contacting the air and hence from rusting.

Wire dot print head having a bipartite partitioning sheet

A wire-type print head comprises an armature to which a rear end of a printing wire is fixed, a core having its forward end adjacent to a rear surface of the armature, a leaf spring having a first end fixed near a permanent magnet and a second end fixed to the armature, and an auxiliary core positioned between the permanent magnet and the core, and having a forward end adjacent to the rear surface of the armature. An electric current is made to flow through a coil wound on the core for generating a magnetic flux through the core in a direction to cancel the magnetic flux due to the permanent magnet. When the coil is not energized the armature is attracted toward the core to resiliently deform the leaf spring. When the coil is energized the armature is released and moved forward by the action of the leaf spring. The rear surface of the armature is kept in contact with the front end of the auxiliary core so that the front end of the auxiliary core forms a fulcrum point for swinging of the armature.

Wire-type printing head

Growing community of inventors

Tokyo, Japan

Katsuya Kamimura