Smith Corona Corp.

Scm Corporation

Stephen M Pawlak

Roger J Rimbey

Donald G Anderson, Jr

Mark D Rodee

An improved quiet impact printer mechanism for use with a typewriter or printer which includes a print hammer having a significant mass for impacting a character pad against an ink ribbon, paper and a platen. A first embodiment has a drive means providing insignificant inertia through the use of a cam driven by an inexpensive, low torque reversible motor which is coupled to the hammer through a cam follower. The cam arrangement may also propel the hammer toward the platen under a predetermined series of controlled velocities. A second embodiment of a printer mechanism, similar to that described above, includes a rotary member driven by a motor link, coupled to the print hammer for moving the hammer toward and away from the platen. The motor link includes an acoustic noise reducing means.

Quiet impact printer mechanism

An improved quiet impact printer mechanism for use with a typewriter or printer which includes a print hammer having a high effective mass at the print point for impacting a character pad against an ink ribbon, paper and a platen at a relatively low velocity. The pinter mechanism drive means includes a cam driven by a low torque reversible motor for moving a cam follower. The cam follower is coupled to the hammer by means of a pin and moves the hammer towards the platen. The cam may also cause movement of the hammer toward the platen under a predetermined series of controlled velocities.

A printing device including a print hammer having a noise dampener for use with an impact printer mechanism. The print hammer has a significant mass for impacting a character pad against an ink ribbon, paper and a platen. In a first embodiment the print hammer includes an acoustic noise dampening layer interposed between a mass weight and the hammer face which carries the anvil that impacts during printing. In other embodiments the print hammer is formed in two parts. One part having a weighted mass and the other part being pivotally coupled to the printer mechanism. The two parts are structurally joined together by a noise dampening member. Transmission of acoustic noise during impact printing through the hammer is reduced.

Printing mechanism with print hammer having noise dampener

An improved solenoid wherein the volume of a secondary air gap is increased during the plunger stroke, in order to reduce the increased plunger force that would otherwise occur during the plunger stroke.

Solenoid device

A ribbon feed mechanism for printing machines has a motor coupled to a ribbon drive mechanism for feeding a ribbon in response to energization of the motor. A control mechanism is coupled to the ribbon drive mechanism and responsive to the ribbon drive mechanism during ribbon feeding for limiting the amount of ribbon feed to predetermined feed increments.

Ribbon feed mechanism

A ribbon feed mechanism for printing machines has a toothed wheel rigidly mounted on a drive shaft at an angle relative to a plane perpendicular to the drive shaft axis. The toothed wheel will penetrate layers of outer convolutions of a roll of film ribbon on a take-up spool at varying locations relative to the ribbon width for feeding the film ribbon with equal length increments more consistently.

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Cortland, NY, United States of America

Stephen M Pawlak