Scanner that controls stepping motor torque

  • US 6,414,461 B1
  • Filed: 12/21/2000
  • Issued: 07/02/2002
  • Est. Priority Date: 12/21/2000
  • Status: Expired due to Term
First Claim
Patent Images

1. A scanner comprising:

  • a housing having a transparent platform, a document to be scanned being placed on the transparent platform;

    a scanning module movably installed inside the housing for scanning the document;

    a driving module installed inside the housing for driving the scanning module, the driving module comprising;

    (a) a stepping motor for driving the scanning module forward and backward so that the scanning module scans the document; and

    (b) a motor driving circuit for controlling the stepping motor according to a driving signal; and

    a control circuit for controlling the operations of the scanner, the control circuit comprising a memory, the memory storing a torque table and a driving program, the torque table recording a plurality of torque values, each of the torque values corresponding a predetermined condition when the stepping motor produces the corresponding torque, and the driving program chooses one of the torque values according to the predetermined condition, the motor driving circuit receiving the corresponding driving signal according to the torque value chosen by the driving program and controlling the stepping motor so that the stepping motor generates a torque according to the driving signal;

    wherein the control circuit controls the stepping motor to generate different torque so that the scanning module scans the document at different speeds.

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