Abstract: A carriage mechanism for a printer comprises an ink ribbon take-up mechanism for taking up an ink ribbon, a head moving mechanism for moving a printing head which is provided on a carriage between a printing position where the printing head can carry out a printing operation by transferring ink coated on the ink ribbon on a recording paper and a non-printing position where the printing head does not carry out the printing operation, and a single driving source for selectively driving the ink ribbon take-up mechanism and the head moving mechanism.

Abstract: In the demand-type ink jet printer head driving method and apparatus a predetermined voltage is applied to an electromechanical conversion device in a preliminary step to displace the wall of an ink pressure chamber inwardly. This decreases the volume of the pressure chamber without ejecting ink from the nozzle. The applied voltage is removed to restore the wall of the pressure chamber by means of the elastic energy stored in the wall and in the electro-mechanical conversion means thereby drawing ink into the pressure chamber from an ink reservoir container. Voltage is applied a second time to the electro-mechanical conversion device in synchronism with a damped oscillation system comprised of the pressure chamber wall, the electro-mechanical conversion means, and ink. The second application of voltage in synchronism with the damped oscillation displaces the electro-mechanical conversion means inwardly so that an ink droplet is ejected from the nozzle.

Abstract: In a miniature printer for printing with dots on printing paper, concentrically mounted driving cams provide both horizontal and vertical motions which synchronize the reciprocating action of the printing head mechanism with the paper feed and ink ribbon feed mechanism. Constant velocity linear motion is provided for the print head. The printing paper may be removed in either direction from the printer.

Abstract: The head portion of a dot printer includes a cup-shaped yoke, an electromagnet on a coil frame, an iron core within said coil frame, said core being securely fixed to said cup-shaped yoke, a second yoke, a movable element comprising a second iron core disposed for attraction by said electromagnet and a holding member for holding said movable element for rotation around a fulcrum on said fulcrum member. The structure is such that tolerances can be held closely in mass production, thereby providing high reliability and high quality printing at low cost.

Abstract: A printer including a printing head adapted for reciprocal displacement across a printing tape for effecting printing on the tape in at least one direction of reciprocation is provided. The printer includes a lever pivoted on a frame and adapted to reciprocate the printing head and a rotating disc engaged with a motor for driving the rotary disc which pivots the lever. The rotating disc is adapted to actuate a paper advance assembly, an ink-ribbon winding assembly and an ink-ribbon reversing assembly. The printing head may be of the type including a plurality of needles for recording dots by electromagnetic actuation of the needles.

Abstract: An improved printer comprising a plurality of character rings provided with a plurality of characters on the respective peripheries thereof and corresponding pluralities of ratchet wheels and pawls. Each ratchet wheel is radially mounted on a character ring and a corresponding pawl is oscillatably mounted for engaging its corresponding ratchet at a preselected interval for stopping its associated character ring when a selected character is located at a predetermined position. Guides are provided for determining the constancy of oscillation of the pawls. Each pawl is spring driven into engagement with a corresponding ratchet wheel and a normal bias toward a corresponding ratchet wheel is provided. A releasable restraint acts oppositely to the bias on the pawl for normally preventing the pawl from engaging with its corresponding ratchet wheel.

Abstract: An improved printer comprising a plurality of character rings provided with a plurality of characters on the respective peripheries thereof and corresponding pluralities of ratchet wheels and pawls. Each ratchet wheel is radially mounted on a character ring and a corresponding pawl is oscillatably mounted for engaging its corresponding ratchet at a preselected interval for stopping its associated character ring when a selected character is located at a predetermined position. Guides are provided for determining the constancy of oscillation of the pawls. Each pawl is spring driven into engagement with a corresponding ratchet wheel and a normal bias toward a corresponding ratchet wheel is provided. A releasable restraint acts oppositely to the bias on the pawl for normally preventing the pawl from engaging with its corresponding ratchet wheel.

Abstract: A parallel printer including an improved reset mechanism for resetting a ratchet and pawl mechanism after printing, is provided. An axially rotatable shaft having notched portions associated with each pawl effects a pivoting of each pawl out of engagement with the corresponding ratchet wheel and returns each pawl to a rest position to complete a printing cycle.