Method of discriminating and change a yarn package

In a fluid jet loom in which a weft yarn is unwound from a yarn package, the weft yarn is measured and stored by a measuring and storing device, and then the weft yarn stored in the measuring and storing device is picked into a shed, a method of discriminating and changing a yarn package, comprising:

• a picking condition detecting step in which detecting matters for evaluating the weft yarn are detected while the picked weft yarn is running along the running path and detection signals representing the matters detected are generated;
• a data storing step in which data corresponding to the detection signals generated in the successive picking cycles are stored sequentially;
• a yarn package quality deciding step in which the stored data is read and yarn package changing instruction is provided to change the yarn package feeding the weft yarn at present for a new yarn package when data indicates that the yarn package feeding the weft yarn at present is defective;
• and
• a yarn package changing step in which, in response to the yarn package changing instruction, the yarn package feeding the weft yarn at present is shifted from the feed position to the removing position and a new yarn package is located at the feed position, and the weft yarn of the new yarn package is unwound from the new yarn package and is extended to the measuring and storing device.