Linear motor and image reading apparatus

An image reading apparatus comprising:

• a rod-like stator including a magnetizable rod-like member provided by magnetization with both a drive field magnet and a plurality of magnet portions providing multiple kinds of position information;
• first and second movable pieces each being movable along said stator, and each having an armature coil opposed to said field magnet and a sensor for reading the position information from said plurality of magnet portions;
• a first slider for scanning a document image, which is coupled to said first movable piece;
• and
• a second slider coupled to said second movable piece for cooperating with said first slider for scanning the document image.

A linear motor comprising:

• a rod-like stator having a drive field magnet;
• and
• a movable piece including an armature coil fitted around said stator, wherein
• said stator has a stepped portion at the surface of its portion provided with said field magnet, and
• said movable piece has a sensor disposed near said stepped portion for reading a signal from said stator.

An image reading apparatus comprising:

• a first slider being reciprocatable and carrying a first mirror reflecting, in a predetermined direction, image light coming from a document;
• a second slider being reciprocatable in the same direction as said first slider and carrying a second mirror leading, in a predetermined direction, the image light coming from said first mirror;
• a first motor for reciprocating said first slider;
• a second motor for reciprocating said second slider;
• a first absolute encoder for sensing a current position of said first slider;
• a second absolute encoder for sensing a current position of said second slider;
• and
• control means for controlling said first and second motors to move said first and second sliders to their initial positions without mutual collision based on the current positions of said sliders sensed by said encoders, respectively, upon start of supply of a power from a power source to the apparatus.

An image reading apparatus comprising:

• a first slider being reciprocatable and carrying a first mirror reflecting, in a predetermined direction, image light coming from a document;
• a second slider being reciprocatable in the same direction as said first slider and carrying a second mirror leading, in a predetermined direction, the image light coming from said first mirror;
• a first motor for reciprocating said first slider;
• a second motor for reciprocating said second slider;
• a first scale;
• a first encoder for sensing a current position of said first slider using the first scale;
• a second scale;
• a second encoder for sensing a current position of said second slider using the second scale;
• and
• control means for controlling said first and second motors to move said first and second sliders to their initial positions without mutual collision based on the current positions of said slider sensed by said encoders, respectively, upon start of supply of a power from a power source to the apparatus.