| 摘要 |
Provided is a magnetic sensor device which, in addition to determining the presence or absence of a magnetic body portion on a medium, is capable of determining whether the magnetic body portion is a hard magnetic material or a soft magnetic material. Specifically, the magnetic sensor device 20 is provided with permanent magnets 30 for forming, in the conveyance path 11 of a medium M, a magnetic field in a direction along the conveyance direction A1 of the medium M, and magnetic sensitive elements 40 disposed within the magnetic field of the permanent magnets 30 on the conveyance path 11 side relative to the permanent magnets 30. When the medium M passes through the conveyance path 11, the direction in which the magnetic field at the positions where the magnetic sensitive elements 40 are disposed changes as a result of the effect of the magnetic permeability of the magnetic pattern (magnetic body portion) on the medium M is only the direction of increasing magnetic field. In contrast, the direction in which the magnetic field at the positions where the magnetic sensitive elements 40 are disposed changes as a result of the effect of the residual magnetic flux density of the magnetic pattern is both the direction of increasing magnetic field and the direction of decreasing magnetic field. As a result, it is possible to determine whether the magnetic pattern is a hard magnetic material or a soft magnetic material on the basis of the output from the magnetic sensitive elements 40. |
