Transmission mechanism of image scanner with adjustable resolution

An apparatus, comprising:

• a transmission control means for switching between a first and a second transmission states in response to a command for changing a moving speed of a carriage;
• a first transmission means for receiving transmission power from said transmission control means in the first transmission state;
• a second transmission means for receiving transmission power from said transmission control means in the second transmission state;
• wherein said transmission control means comprises an active means for synchronously rotating with a shaft of a step motor;
• two follower means for engaging with said active means for transmission by said active means;
• a swing means for swinging between a first position to allow said follower means to engage with said first transmission means and a second position to allow said follower means to engage with said second transmission means;
• a holder means for selectively holding said swing means to fix the swing means in one of the first and second transmission states to allow said carriage to move at said selected speed;
• and
• means for retracting said holder means to release said swing means in order to change said moving speed of said carriage, and means for protracting said holder means to confine said swing means in order to fix the swing means in one of the first and second transmission states for a back and forth scanning operation.

A scanner comprising:

• a first gear set coupled to a common transmission gear;
• a second gear set coupled to the common transmission gear;
• a drive gear coupled to a motor;
• a cyclic belt coupled to the common transmission gear to be driven thereby;
• a carriage comprising an image sensor mounted to the cyclic belt;
• a swing arm pivotally mounted concentric with the drive gear;
• a transmission gear set secured to the swing arm and meshed with the drive gear;
• and
• a holder selectively engaged with the swing arm to retain the swing arm in either a first or second position for both forward and backward movement of the carriage, the transmission gear set meshed with the first gear set in the first position and meshed with the second gear set in the second position.

A method comprising:

• disengaging a holder from a swing arm having a transmission gear set secured thereto, the swing arm pivotable concentrically with rotation of a drive gear meshed with the transmission gear set;
• actuating the drive gear such that the drive gear urges the swing arm from a first position to a second position, the transmission gear set meshed with a first gear set in the first position and meshed with a second gear set in the second position, the first and second gear sets coupled to a common transmission gear;
• and
• reengaging the holder with the swing arm such that the swing arm is retained in the second position for both clockwise and counterclockwise rotation of the drive gear.

A transmission device comprising:

• a first means for transmitting coupled to a common transmission gear;
• a second means for transmitting coupled to the common transmission gear;
• a means for driving coupled to a motor;
• a means for rotating;
• a third means for transmitting mounted to the means for rotating and engaged with the means for driving;
• and
• a means for retaining the means for rotating in both a first position for both clockwise and counter clockwise rotation of the motor or a second position for both clockwise and counter clockwise rotation of the motor, the third means for transmitting engaging the first means for transmitting in the first position and engaging the second means for transmitting in the second position.