Hitachi Metals, Ltd.

Other

Fumio Kimura

Masumi Asanae

Masahiro Mita

Masahiro Masuzawa

Toshiko Takahashi

Koji Noguchi

Masahisa Ochiai

Toshihiko Noshiro

Akihiko Funakawa

Kenichi Kitta

Ryuji Gotoh

Takehiro Takahashi

Disclosed is a permanent magnet generator incorporated in a 3.5&Prime; diskette that can be used as an input/output adapter for memory cards that can generate a power generation output of 40 mW or more when the rotor of the generator is rotated at 300 rpm. The permanent magnet generator has such a construction that rotor magnetic poles are provided only on one end face of a disc-shaped permanent magnet serving as a rotor, a plurality of stator magnetic poles are provided only on that end face of the permanent magnet in such a manner as to face the rotor magnetic poles, and a soft magnetic hub is fixedly fitted to the other end face of the permanent magnet. Even when a bonded NdFeB magnet is used as the permanent magnet, a sufficient power can be produced.

Thin type permanent magnet generator and diskette incorporating same

A diskette incorporating a flat disk-shaped permanent magnet generator is disclosed. This permanent magnet generator comprises a rotor having a permanent magnet that can rotate together with a hub; the permanent magnet having a plurality of rotor magnetic poles on the circumference thereof, and a stator comprising a plurality of magnetic pole teeth having on one end thereof stator magnetic poles that can face the rotor magnetic poles via a magnetic gap. The magnetic pole teeth extend from the stator magnetic poles outside of the rotor, with stator coils wound on the extended portions of the magnetic pole teeth and the outside ends of the magnetic pole teeth connected to each other by a back yoke. The thickness of the outward extending magnetic pole teeth is smaller than the thickness of the permanent magnet. The diskette should preferably be a 3.5&Prime; floppy disk.

Diskette incorporating a permanent magnet generator having a stator with magnetic pole teeth that are axially thinner than a permanent magnet that cooperates with the stator

A permanent magnet generator incorporated in a diskette that can be inserted into a floppy disk drive is disclosed. In the permanent magnet generator, electric power is generated as a rotor is caused to rotate at a revolution twice to ten times as high as that of the drive shaft of a floppy disk drive by transmitting the rotation of the drive shaft to a rotor via a speed increasing mechanism incorporated in a diskette. Since the cogging torque of the generator is reduced, the rotor can be caused to rotate with a small drive torque. This allows the generator to produce a high output.

Diskette incorporating permanent magnet generator

In a diskette, such as a 3.5&Prime; floppy disk, having adjoiningly a permanent magnet generator and a space for inserting a memory card with a magnetic stripe, the affection of leakage magnetic flux from the generator permanent magnet to the memory card and another floppy disk that may be put in the neighborhood of the diskette is substantially eliminated and the generator output is increased. A magnetic shield is disposed only at the portion corresponding to the magnetic stripe of the memory card on a generator housing or a partition between the generator permanent magnet and the memory card space. A magnetic shield ring with a diameter substantially equal to or larger than the outside diameter of the permanent magnet is fixed or pasted on one side end of the rotor permanent magnet adjacent to one of the ends of the diskette case.

Diskette incorporating permanent magnet generator with low leakage flux

A permanent magnet generator is so thin as to be incorporated in a 3.5&Prime; diskette. The generator having so low cogging torque that can be rotated smoothly even by a low torque driving source as a 3.5&Prime; FDD to generate stable output is disclosed. It has stator magnetic poles facing via a magnetic gap an outer circumferential surface of the stator permanent magnet having a plurality of magnetic poles on it. One to six of the stator magnetic poles are removed and instead of the removed magnetic poles provided is a soft magnetic piece to face the rotor magnetic poles. Grooves are preferably provided on the soft magnetic piece, facing the rotor magnetic poles. A notch is provided on the permanent magnet generator to avoid interference with an input/output terminal and/or a card contact terminal of the diskette for inserting a memory card.

Diskette incorporating permanent magnet generator with reduced cogging torque and permanent magnet generator for use in diskette

A two-component magnetic developer of the invention for printing characters on documents for magnetic ink character recognition comprises the mixture of 20 to 80 percent by weight of a magnetic toner containing binder resin and magnetic powder and the balance being a magnetic carrier, wherein the magnetic toner has magnetic powder of 30 to 60 percent by weight, residual magnetization .sigma.r of 4 to 16 emu/g and average particle diameter of 5 to 15 um. The developer rarely causes background fogging and carrier adhesion on the developed images which is suitable for MICR.

Two-component magnetic developer for printing characters for magnetic

A magnetic toner includes at least binding resin (for instance, a styrene-acryl resin) and magnetic powder (for instance, Mn--Zn ferrite or Ni--Zn ferrite) having a saturation magnetization of at least 50 emu/g and a coercive force as measured under the magnetic field of 10 kOe not exceeding 50 Oe. An image formed by using this magnetic toner has high quality and is free of tailing.

Magnetic toner

Method for recording images

In a method of developing a electrostatic charge pattern in which a magnetic brush is formed by supplying a developer consisting of a magnetic carrier and a magnetic toner onto a non-magnetic sleeve disposed so as to face an image carrier surface and incorporating a magnetic field producing member, the magnetic toner contains 25 to 60% by weight of a magnetic powder and the coercive force of the magnetic toner is not greater than 60 Oe. Preferably, the coercive force of the magnetic toner is not smaller than 15 Oe. The magnetic toner is composed, of, for example, styrene.sub.n -butylacrylate copolymer, magnetite and a charge control agent.

Method of developing electrostatic charge pattern with magnetic developer

A reverse development method comprising the steps of forming electrostatic image on the surface of an image-bearing member; supplying a developer comprising chargeable magnetic toner based on magnetic powder and a resin development roll comprising a conductive core, a permanent magnet arranged around the conductive core and a dielectric layer provided around and fixed to the permanent magnet and having conductive particles mutually insulated from each other; conveying the developer onto a surface of the image-bearing member by rotation of the developement roll so that the magnetic toner is attracted to the uncharged portions of the image; characterized in that the chargeable magnetic toner contains an aliphatic acid metal salt and is coated with hydrophobic silica.

Reverse development method

In a developer containing as toner at least a resin component and a coloring agent, when (A) a styrene-acrylic copolymer and (B) a polyester resin is used as the resin component and making the toner to have an electric resistance of 10.sup.13 .OMEGA..cm or higher and a triboelectrification quantity of an absolute value of 5 .mu.C/g or more, the resulting developer shows no offset phenomenon and gives excellent image quantity, transfer efficiency and good productivity.

Growing community of inventors

Gyoda, Japan

Fumio Kimura