Magnetic powder for validity determining ink, manufacturing method for magnetic powder for validity determining ink, magnetic ink for validity determination, printing member for validity determination,detecting device for printing member for validity determination, and validity determination device
AssigneeKabushiki Kaisha Toshiba
InventorsTakao Sawa, Katsutoshi Nakagawa, Teruo Murakami, Tadahiko Kobayashi, Hisashi Takahashi, Masao Obama
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Abstract
The magnetic powder for validity determining ink is composed of magnetic oxide powder having a Curie temperature between −50° C. and 150° C. and a mean powder particle diameter of 10 μm or less.
Claims18
Magnetic powder for validity determining ink comprising magnetic oxide powder having a Curie temperature between −50° C. and 150° C. and a mean powder particle diameter of 10 μm or less.
A manufacturing method for magnetic powder for validity determining ink, comprising the steps of:
- dissolving a magnetic oxide material and a glass forming material to obtain a mixture thereof;
- cooling the mixture rapidly to make the amorphous magnetic oxide;
- heat-treating the amorphous mixture to crystallize the magnetic oxide;
- and
- removing the glass forming material from the crystallized mixture to obtain magnetic oxide powder having a mean powder particle diameter of 10 μm or less.
Magnetic ink for validity determination including first magnetic powder having a Curie temperature between −50° C. and 150° C. and a mean powder particle diameter of 10 μm or less.
A printing member for validity determination, comprising:
- a base;
- a first magnetic image printed on the base with first magnetic ink including first magnetic powder having a first Curie temperature;
- and
- a second magnetic image printed on the base with second magnetic ink including second magnetic powder having a second Curie temperature higher than that of the first magnetic powder.
A detecting device for a printing member for validity determination, comprising:
- means for conveying a printing member for validity determination having a first magnetic image printed with first magnetic ink including first magnetic powder having a first Curie temperature and a second magnetic image printed with second magnetic ink including second magnetic powder having a second Curie temperature higher than the same of the first magnetic powder;
- a heater for heating the printing member for validity determination to a temperature higher than the first Curie temperature and lower than the second Curie temperature;
- and
- magnetic characteristic detecting means for detecting magnetic characteristics from the heated printing member for validity determination.
A validity determining device, comprising:
- means for conveying a printing member for validity determination having a first magnetic image printed with first magnetic ink including first magnetic powder having a first Curie temperature and a second magnetic image printed with second magnetic ink including second magnetic powder having a second Curie temperature higher than the same of the first magnetic powder;
- a heater for heating the printing member for validity determination to a temperature higher than the first Curie temperature and lower than the second Curie temperature;
- a first magnetic detecting section installed at a preceding stage of the heater for detecting magnetic characteristics from the printing member for validity determination;
- a second magnetic detecting section installed at a later stage of the heater for detecting magnetic characteristics from the printing member for validity determination;
- and
- a validity determining section for determining validity of the printing member for validity determination from a first magnetic property detected by the first magnetic detecting section and a second magnetic property detected by the second magnetic detecting section.
Dependencies are inferred from the claim text.