| 摘要 |
<p>PURPOSE:To simplify structure and to facilitate handling by inspecting and selecting automatically by non-contact a minute magnetic foreign matter contained in a form offered for printing by magnetic ink, by a magnetic sensor while the form is running. CONSTITUTION:When a minute foreign matter for obstructing read of a character printed by magnetic ink is contained in a form 1, a leakage flux of a void part of a core in a magnetic head 2 is varied. This variation of the leakage flux of the void part of the core is related to magnetic permeability of the magnetic foreign matter, and the magnetic head 2 generates a voltage being proportional to the variation of the leakage flux. The voltage which has been generated by the magnetic head 2 is amplified by an amplifying circuit 5, whether the magnetic foreign matter exists or not is decided by a positive loss deciding circuit 6, and a result is sent to an output circuit 7. When the magnetic foreign matter is detected, an electric signal is sent to a shift register 18 by the output circuit 7, a selecting gate is opened and closed by a selecting gate driving circuit 19, and only good paper is stacked up in a good paper pile.</p> |
