Abstract: In a printer which selects a character by moving a type wheel by a stepping motor, phases other than a stable phase of windings of the stepping motor are shorted when a rotor of the stepping motor comes to a vicinity of a stable point of a target phase, and an exciting time of the stable phase is gradually extended. The primary drive signal is turned off during energization of a retaining signal and during hammer energization.

Abstract: A home position detecting apparatus includes a detector to generate a detection signal when the home position of a print wheel is detected and a stepping motor to rotate the print wheel in response to a drive signal. This home position detecting apparatus further includes a control circuit which gives the drive signal having a specific phase to the stepping motor in response to the detection signal from the detector.

Abstract: A print disk positioning system is disclosed herein which provides rotational and lateral movement of a print disk (20) having raised or depressed characters thereon with the objective of locating the appropriate character within the jaws of a printing station (22). The positioner includes a fixed rail (44) which is driven by the rotation of a motor (38) having a pinion gear (42) which drives a rack gear (82) connected to a rack arm (80) which in turn slides a second motor (54) mounted on bearings (56) on rail (44). Motor (54) provides the rotational movement to the disk and motor (38) provides the lateral movement. Each motor is controlled electrically to cause an appropriate sequence of movements to bring the disk into proper alignment in the printing station at the appropriate time.

Abstract: A serial printer comprising a print wheel having numerous type bearing spokes, each of which extends radially and which is provided with a type element on the tip of the spoke, a stepping motor for rotating the print wheel, a print hammer for striking the desired spoke behind the type element during printing operation, a positioning means for guiding a selected type element to a printing point during the striking operation of the print hammer, and a control circuit for regulating the driving of the stepping motor and the print hammer. The control circuit causes the stepping motor to move the selected type element to a position whereat the type element is struck by the print hammer. The control circuit suspends the energize-hold operation of the stepping motor at the moment that the type element is struck by the print hammer. This invention accurately positions the type element for substantially aligned printing operation, and greatly reduces damage to the spokes due to material fatigue.

Abstract: An electronic typewriter comprising: a keyboard having a plurality of keys and generating an encoded signal in response to the depression of each key; a printing unit having a print wheel with a plurality of type elements disposed around the periphery thereof, a step motor for rotating the print wheel, a print hammer for impacting the type element brought to a printing position, an ink ribbon, and a ribbon drive mechanism for bringing the ink ribbon to the printing position; and an electronic control circuit for coupling the keyboard to the printing unit. The electronic control circuit controls the rotation of the step motor according to the encoded signal received from the keyboard so as to bring a type element selected by the encoded signal to the printing position within a short time for executing quicker printing, and further controls the action of both the print hammer and the ribbon drive mechanism in response to the rotation of the step motor.

Abstract: A printer has a horizontally movable carrier which supports a print head including a print element on which are disposed type characters in a two dimensional array with the element controllably movable by motors in two degrees of freedom to selectively position each type character opposite a record-medium-carrying platen for printing. The print head is on a rocker having a cam follower which cooperates with a cam on a shaft driven by a variable speed motor which is also on the carrier. During printing the motor speed is controlled so that the print element is driven against the platen with a force related to the particular character being printed. The motor speed is further controlled so that there is not only a minimum wait between the printing of successive characters but there are also minimum accelerations and decelerations of the motor.

Abstract: A printer has a print shell on which are disposed type characters in a two dimensional array with the shell controllably movable in two degrees of freedom to selectively position each type character opposite a record-medium-carrying platen for printing. In addition, during printing the shell is driven against the platen with a force related to the particular character being printed, and associated with the printing is an indexing or transverse spacing of the print shell to expose new portions of the record medium for printing.