Browse Prior Art Database

Linear Print Hammer Actuator

IP.com Disclosure Number: IPCOM000061313D
Original Publication Date: 1986-Jul-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 3 page(s) / 65K

Publishing Venue

IBM

Related People

Hara, K: AUTHOR [+3]

Abstract

Using a shuttling bank of plastic linear impactors, each having an iron cap which serves as a combination of an impactor head and magnetic return to a permanent magnet, provides an effective economical print actuator system for midrange printers. The design uses a shuttling group of linear impactors with plastic bodies and steel caps, embedded in a plastic guide. It reduces manufacturing cost, provides low mass, and permits the use of a magnetic field as a return mechanism, without springs. An available low cost hammer bank may be used for the magnetic actuator with an initial gap between the armature and impactor, which can be altered for various energy and operating ranges. Fig. 1 shows the actuator consisting of shuttling impactor unit 1 and stationary actuator unit 2.

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Linear Print Hammer Actuator

Using a shuttling bank of plastic linear impactors, each having an iron cap which serves as a combination of an impactor head and magnetic return to a permanent magnet, provides an effective economical print actuator system for midrange printers. The design uses a shuttling group of linear impactors with plastic bodies and steel caps, embedded in a plastic guide. It reduces manufacturing cost, provides low mass, and permits the use of a magnetic field as a return mechanism, without springs. An available low cost hammer bank may be used for the magnetic actuator with an initial gap between the armature and impactor, which can be altered for various energy and operating ranges. Fig. 1 shows the actuator consisting of shuttling impactor unit 1 and stationary actuator unit 2. The impactor unit 1 shuttles back and forth to cover two character positions. The actuator unit 2 does not move. The back 3 of impactor 4 is sufficiently wide to contact the tip 5 of the related armature, whether in the left or right shuttle position. The impactor unit 1 shuttles back and forth to cover the whole line. Fig. 2 shows the printing procedure step by step. The reason for choosing the narrow impactor is that the impactor mass should be as small as possible to achieve high print quality by minimizing contact time. If a two- character-width printing surface were chosen, to avoid shuttling the impactor unit, the band speed would have to be increased to keep the same print speed because the character pitch on the band would have to be wider. This would reduce the print quality and also increase the contact time due to the heavier impactor mass. First, at the left position, each impactor prints a character at the odd character position (A) (1,3,5, etc., positions). Then the impactor unit 1 moves to the right to print the character at the even position (B) (2,4,6, etc., positions). After the paper increments, the characters at the even positions on the second line are printed (C). Then the impactor unit shuttles back to the left to cover the rest of the characters (D), and so forth. Impactor unit 1 has plastic impactors 4 enclosed in tunnels in a plastic impactor guide 6 with a hardened silicon or carbon iron impact head 7. The impactors are fitted loosely to prevent large sliding friction. Since the printing speed is relatively low, the flight time variation due to the loose fit is not a problem. Plastic material is used extensively in order to reduce both the mass (to minimize the contact time, and vibration due to the shuttling) and the manufacturing cost. Since the impactors are located two print positions apart, center to center, the packaging and manufacturing are simplified. With a return spring, the force is proportional to the displacement; the impactor gets the strongest return force at printing and the weakest force at settling out, which results in high potential energy loss (low efficiency) and longer settle out time...