Tape medium running device

• US 6,851,639 B2
• Filed: 03/03/2003
• Issued: 02/08/2005
• Est. Priority Date: 03/05/2002
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Nakamura, Kenjiro, Tanabe, Naohisa
• Primary Examiner(s): RIVERA, WILLIAM ARAUZ
• Application Number:
  US10/377,103
• Publication Number:
  US 20040079825A1
• Time in Patent Office: 708 Days
• Field of Search: 242/333.6, 242/333.7, 242/334, 242/334.1, 242/334.5, 242/413, 242/413.1, 242/413.2, 242/413.9, 242/419.2, 242/421.2, 242/357, 242/412.1, 242/412.2, 360/71
• US Class Current: 242/334
• CPC Class Codes: G11B 15/06 by sensing auxiliary features on record carriers or containers, e.g. to stop machine near the end of a tape
• CPC Class Codes: G11B 15/26 Driving record carriers by members acting directly or indirectly thereon G11B15/44 takes precedence; driving features inside container, see G11B23/04 and subgroups
• CPC Class Codes: G11B 15/44 Speed-changing arrangements; Reversing arrangements; Drive transfer means therefor

Abstract

A tape medium running device which can more correctly detect erroneous detection of a winding diameter, prevent an approach from being made to the end of the magnetic recording tape at high running speed and causing a damage on the tape, and can shorten fast forwarding/rewinding time. In this device, a winding diameter change detecting unit detects a change in winding diameter, and a ratio of a detected change in diameter and a maximum value of changes in winding diameter having been detected previously is compared with a predetermined winding diameter change comparison reference to detect abnormality. Thus, it is possible to prevent any approach from being made to the end of the magnetic recording tape at a high running speed based on an erroneous detection to causing a damage on the tape, and to shorten time for fast forwarding and rewinding.

Claims

1. A tape medium running device, for reducing a first winding speed to a second speed lower than said first speed as a function of a winding diameter of a magnetic recording tape wound around a reel, at a position near an end of such magnetic recording tape being wound from one reel to another reel at the first speed, the device comprising:

a motor;

a rotation detecting unit for detecting a signal of a frequency proportionate to a rotation speed of the motor;

a take-up reel which is wound with one end of such magnetic recording tape and rotates in synchronization with a rotation speed of the motor;

a supply reel which is wound with the other end of such magnetic recording tape;

a winding diameter detecting unit for detecting a winding diameter of such magnetic recording tape wound around the supply reel;

a reference high speed calculating unit for outputting a first reference speed for setting the rotation speed of the motor at the first speed;

a reference low speed calculating unit for outputting a second reference speed for setting the rotation speed of the motor at the second speed;

a winding diameter comparing unit for comparing an output from the winding diameter detecting unit and a winding diameter comparison reference value previously set in the winding diameter comparing unit;

an abnormality detecting unit for detecting abnormality based on an output from the winding diameter detecting unit;

a reference speed setting unit for outputting an output from the low reference speed calculating unit as a third reference speed when an output from the abnormality detecting unit indicates abnormality or when an output from the winding diameter detecting unit is detected to be smaller than the winding diameter comparison reference value, and outputting an output from the high reference speed calculating unit as a fourth reference speed in other cases;

a speed control unit for outputting a rotation instruction signal based on an output from the rotation detecting unit and an output from the reference speed setting unit, and

a drive unit for rotating the motor in response to the rotation instruction signal,

the abnormality detecting unit comprising;

a winding diameter change detecting unit for detecting a change in winding diameter on a basis of a winding diameter detected by the winding diameter detecting unit; and

an abnormal winding diameter change judging unit for judging whether the winding diameter detected by the winding diameter detecting unit is correct or not on a basis of a winding diameter change comparison reference and a change in diameter detected by the winding diameter change detecting unit, and notifying the reference speed setting unit of an occurrence of abnormality.

2. The tape medium running device according to claim 1, further comprising a winding diameter change comparison reference optimizing unit for changing the winding diameter change comparison reference according to a winding diameter change maximum value detected by the winding diameter change detecting unit.

3. The tape medium running device according to claim 2, wherein instead of changing the winding diameter change comparison reference according to the winding diameter change maximum value, the winding diameter change comparison reference is changed according to a statistic value.

4. The tape medium running device according to claim 3, wherein said statistic value is an average value of previously detected winding diameters.

5. The tape medium running device according to claim 1, wherein

the abnormality detecting unit and the reference speed setting unit are controlled by identifying a current tape position according to a plurality of winding diameter comparison reference values previously set in the reference speed setting unit and the winding diameter detected by the winding diameter detecting unit, and

switching is performed, according to each tape position, among a section where the reference speed of the motor is set at the first speed without going through the abnormality detecting unit, a section where the reference speed of the motor is set at the first speed after a change in winding diameter is detected and only a maximum value of the change in winding diameter is stored, a section where a reference speed of the motor is set at the first speed or the second speed through the abnormality detecting unit, and a section where the reference speed of the motor is act at the second speed without going through the abnormality detecting unit, so that two different winding diameter regions are provided, one for detecting abnormality in the change in winding diameter and the other for not detecting the abnormality.

6. The tape medium running device according to claim 1, wherein the second speed of the reference low speed calculating unit is set as a reference speed permitting deceleration from the first speed with passage of time and a final stop at the end of the magnetic recording tape.