Patent ID: 9672679
Date: 2017-06-06
CPC Classifications: G01B,G07D

Claim:
1. A device for detecting a thickness of a sheet medium, comprising: a thickness sensor, a location voltage conversion unit, an A/D converter and a control processor which are connected in the sequence listed, a medium location detecting unit, a timer unit, a D/A converter, and a subtraction and amplification unit, wherein the thickness sensor is configured to detect a thickness of a detected medium and output a location signal indicating the thickness of the detected medium; the location voltage conversion unit is configured to convert the location signal outputted from the thickness sensor into a voltage signal; the medium location detecting unit is connected to the control processor and is configured to detect whether the detected medium passes; the timer unit is connected to the control processor and is configured to record a running time of the device according to a preset rule, wherein the timer unit resets before detection of the detected medium and starts when the medium location detecting unit detects the detected medium; two terminals of the D/A converter are connected to the control processor and an inverting input terminal of the subtraction and amplification unit respectively, and the D/A converter is configured to convert a digital signal into an analog signal; a non-inverting input terminal for receiving the voltage signal from the location voltage conversion unit, the inverting input terminal and an output terminal of the subtraction and amplification unit are connected to the location voltage conversion unit, the D/A converter and the A/D converter respectively, and the subtraction and amplification unit is configured to perform subtraction and amplification on the voltage signal and the analog signal; and the control processor is configured to: output compensation data with a value of 0 to the D/A converter, read and process thickness data processed by the A/D converter, to obtain actual compensation data, before the detected medium arrives at the medium location detecting unit; output compensation data with value of 0 to the D/A converter, read and process thickness data processed by the A/D converter, to obtain actual compensation data, in a case where a reading of the timer unit is less than a difference T stop calculating the compensation data and output the actual compensation data to the D/A converter, in a case where the reading of the timer unit is equal to T read thickness data processed by the A/D converter, to obtain a real-time thickness of the detected medium which is passing the thickness sensor, in a case where the reading of the timer unit is greater than or equal to T stop reading the thickness data, obtain an actual thickness of the detected medium, and output compensation data with the value of 0 to the D/A converter, in a case where the reading of the timer unit is equal to T wherein the device is initialized in a case where the reading of the timer unit is greater than or equal to T