A magnetic recording medium includes: a substrate that is long in shape; and a magnetic layer containing magnetic powder and a binder. The glass transition point of the binder is not lower than 75° C. In a case where atomic force microscope observation images in a 10 μm×10 μm rectangular shape are acquired at five locations randomly selected from the surface on the side of the magnetic layer, any linear protrusion that is 3 nm to 20 nm in height, is 0.3 μm to 1.0 μm in width, and extends across two sides of the observation image does not exist in the observation images of four locations among the acquired observation images of the five locations.

A problem to be solved by the present invention is to provide a magnetic recording medium having a jet-black magnetic stripe which is not tinged with red. The present invention is directed to a magnetic recording medium including: a magnetic recording layer on a substrate; and a protective layer (a) on the magnetic recording layer, wherein the protective layer (a) contains an aniline coloring material. The magnetic recording medium is advantageous in that the magnetic stripe is jet-black and has excellent design properties, and therefore can be widely used for credit cards, bank cards and the like.

A problem to be solved by the present invention is to provide a magnetic recording medium having a jet-black magnetic stripe which is not tinged with red. The present invention is directed to a magnetic recording medium including: a magnetic recording layer on a substrate; and a protective layer (a) on the magnetic recording layer, wherein the protective layer (a) contains an aniline coloring material. The magnetic recording medium is advantageous in that the magnetic stripe is jet-black and has excellent design properties, and therefore can be widely used for credit cards, bank cards and the like.

A problem to be solved by the present invention is to provide a magnetic recording medium having a jet-black magnetic stripe which is not tinged with red. The present invention is directed to a magnetic recording medium including: a magnetic recording layer on a substrate; and a protective layer (a) on the magnetic recording layer, wherein the protective layer (a) contains an aniline coloring material. The magnetic recording medium is advantageous in that the magnetic stripe is jet-black and has excellent design properties, and therefore can be widely used for credit cards, bank cards and the like.

A problem to be solved by the present invention is to provide a magnetic recording medium having a jet-black magnetic stripe which is not tinged with red. The present invention is directed to a magnetic recording medium including: a magnetic recording layer on a substrate; and a protective layer (a) on the magnetic recording layer, wherein the protective layer (a) contains an aniline coloring material. The magnetic recording medium is advantageous in that the magnetic stripe is jet-black and has excellent design properties, and therefore can be widely used for credit cards, bank cards and the like.

A magnetic recording medium includes: a substrate that is long in shape; and a magnetic layer containing magnetic powder and a binder. The glass transition point of the binder is not lower than 75 C. In a case where atomic force microscope observation images in a 10 m10 m rectangular shape are acquired at five locations randomly selected from the surface on the side of the magnetic layer, any linear protrusion that is 3 nm to 20 nm in height, is 0.3 m to 1.0 m in width, and extends across two sides of the observation image does not exist in the observation images of four locations among the acquired observation images of the five locations.

A magnetic data processing device may include an encryption magnetic head structured to read the magnetic data recorded on the medium. The encryption magnetic head may include a magnetic data reading part structured to read the magnetic data of the medium to output an analog output signal; a demodulation electronic component structured to demodulate the analog output signal outputted from the magnetic data reading part to generate a digital demodulated signal; and an encryption electronic component structured to generate an encrypted signal obtained by encrypting the demodulated signal demodulated by the demodulation electronic component. The encryption electronic component may include at least a first buffer, a second buffer and a third buffer structured to store data having been read at an insertion time and an ejection time of the medium.

The card reader includes a peak detector that detects a peak point of a reproduced signal according to a threshold. The peak detector applies, to a first peak value to be determined, a second peak value immediately before the first peak value, a third peak value, which is the second preceding peak value with respect to the first peak value, and a next peak value. When a difference between a first intermediate value, which is a value between the third peak value and the second peak value, and a second intermediate value, which is a value between the second peak value and the first peak value, is greater than or equal to a first difference value, the peak detector ignores a first threshold, and decides the first peak value after confirming that a digital value corresponding to the next peak value has exceeded a second threshold.

The card reader includes a peak detector that detects a peak point of a reproduced signal according to a threshold. The peak detector applies, to a first peak value to be determined, a second peak value immediately before the first peak value, a third peak value, which is the second preceding peak value with respect to the first peak value, and a next peak value. When a difference between a first intermediate value, which is a value between the third peak value and the second peak value, and a second intermediate value, which is a value between the second peak value and the first peak value, is greater than or equal to a first difference value, the peak detector ignores a first threshold, and decides the first peak value after confirming that a digital value corresponding to the next peak value has exceeded a second threshold.

The card reader includes a peak detector that detects a peak point of a reproduced signal according to a threshold. The peak detector applies, to a first peak value to be determined, a second peak value immediately before the first peak value, a third peak value, which is the second preceding peak value with respect to the first peak value, and a next peak value. When a difference between a first intermediate value, which is a value between the third peak value and the second peak value, and a second intermediate value, which is a value between the second peak value and the first peak value, is greater than or equal to a first difference value, the peak detector ignores a first threshold, and decides the first peak value after confirming that a digital value corresponding to the next peak value has exceeded a second threshold.