ELECTROMAGNETICALLY-ACTUATED PRINTING MECHANISM

• US 3,822,640 A
• Filed: 08/16/1972
• Issued: 07/09/1974
• Est. Priority Date: 08/17/1971
• Status: Expired due to Term

• Current Assignee: Seiki Mizutani, Tsuneta Kawakami, Yasuyoshi Kaneda
• Original Assignee: Seiki Mizutani, Tsuneta Kawakami, Yasuyoshi Kaneda
• Inventors: Mizutani, Seiki, Kaneda, Yasuyoshi, Kawakami, Tsuneta
• Primary Examiner(s): Pulfrey, Robert E.
• Assistant Examiner(s): Pieprz, William
• Application Number:
  US05/281,188
• Time in Patent Office: 692 Days
• Field of Search: 101/93C 310/23 197/18,53 74/128,143,577M,557R,142,123,577R
• US Class Current: 101/93.34
• CPC Class Codes: B41J 7/48 Type carrier arrested in selected position by electromagnetic means
• CPC Class Codes: Y10T 74/1556 Multiple acting
• CPC Class Codes: Y10T 74/2136 Pivoted pawls

Abstract

A printing mechanism comprises a rotary print drum having around the periphery thereof a series of circumferentially spaced-apart rows of print type, a drive system for electromagnetically rotating the print drum in an intermittent manner to successively position the rows of type in a print position, paper feed means for feeding a paper strip to be printed on past the print drum, and an electromagnetically actuated print hammer for striking one of the rows of print type while same is stationary in the print position to print the information contained on that row of type on the paper strip. The drive system comprises a ratchet wheel connected to the print drum, two pawls engageable with different teeth of the ratchet wheel, two electromagnets responsive to alternate pulse signals for electromagnetically reciprocating the pawls in alternate sequence to effect intermittent rotation of the print drum, and an electric control circuit for alternately applying pulse signals to the electromagnets. The operation of the paper feed means is synchronized with the rotation of the print drum to incrementally advance the paper strip one space per one revolution of the print drum and the print hammer is electromagnetically actuated one time during each revolution of the print drum to strike one of the rows of type while same is at rest in the print position.

Claims

1. In a printing mechanism for printing information on a record medium:

a movable type-carrying member carrying thereon n sets of print type successively spaced apart from each other in the direction of movement of said type-carrying member;

electromagnetic drive means responsive to n electric pulse signals for electromagnetically driving said type-carrying member in an intermittent manner in one direction through n equal increments each effected by one pulse signal to effect successive intermittent movement of each set of print type into a common print position thereby defining one printing cycle, said electromagnetic drive means comprising a rotatable ratchet wheel having a set of n/2 ratchet teeth, means connecting said ratchet wheel to said type-carrying member to effect intermittent movement of said type-carrying member in response to intermittent stepwise rotation of said ratchet wheel, a pair of pawls each in engagement with different ratchet teeth of said ratchet wheel and alternately coacting with said ratchet wheel to effect intermittent stepwise movement of said ratchet wheel in response to reciprocatory movement of alternate ones of said pawls, means biasing said pawls into continuous contact with different ratchet teeth of said ratchet wheel, a pivotal plate member having said pawls turnably mounted thereon and operative to alternately reciprocate said pawls in response to reciprocatory pivotal movement of said plate member, means including a pair of electromagnets operative when alternately energized with pulse signal to effect reciprocatory pivotal movement of said plate member thereby intermittently driving said type-carrying member and advancing same through equal increments and means engagable with said ratchet teeth for releasably holding said ratchet wheel and thereby said type carrying member in each successive advanced position;

control circuit means for selectively developing pulse trains composed of n electric pulse signals and applying alternate ones of the pulse signals to respective ones of said pair of electromagnets to effect alternate energization thereof to control the movement of said type-carrying member; and

printing means coacting with said type-carrying member for striking one of said sets of print type when same is stationary in said print position to print the information contained on that set of print type on a record medium.

2. A printing mechanism according to claim 1;

wherein said control circuit means comprises gate means receptive of a continuous train of pulse signals and having a gating state wherein same gates pulse signals to said electromagnetic drive means in response to receipt of a print command signal and a blocking state wherein same blocks the application of pulse signals to said electromagnetic drive means in response to receipt of a blocking signal, and counting means for counting the number of pulse signals gated by said gate means and developing a blocking signal after counting n pulse signals and applying said blocking signal to said gate means to place same in its blocking state until receipt of another print command signal.

3. A printing mechanism according to claim 2;

wherein said gate means comprises an AND gate receptive of said continuous train of pulse signals and operative to gate same to said electromagnetic drive means in response to and during the presence of a gate signal and operative to block the application of pulse signals during the absence of a gate signal, and a flip-flop circuit operative in one stable state wherein same delivers an output gate signal to said AND gate in response to said print command signal and another stable state wherein same delivers no output gate signal to said AND gate in response to receipt of the output signal from said counter means.

4. A printing mechanism according to claim 2;

wherein said control circuit means comprises an AND gate connected to each electromagnet, each AND gate being connected to receive the pulse signals from said gate means and operative to apply same to its respective electromagnet in response to receipt of a gate signal, and a flip-flop circuit having a first stable state wherein same delivers an output gate signal to one AND gate and a second stable state wherein same delivers an output gate signal to the other AND gate and having a trigger input receptive of said pulse signals from said gate means to alternately trigger said flip-flop circuit into its first and second stable states in response to alternate pulse signals.

5. A printing mechanism according to claim 2;

wherein said type-carrying member comprises a rotary print drum having around the periphery thereof n circumferentially spaced-apart and longitudinally extending rows of print type.

6. A printing mechanism according to claim 2;

wherein said printing means comprises a pivotal lever having a pair of lever arms, a print hammer connected to one lever arm and movable into contact with one of said sets of print type when same is in said print position in response to pivotal movement of said lever, an armature connected to the other lever arm, and an electromagnet selectively energizeable to create therearound a magnetic field coacting with said armature to attract said armature towards said electromagnet to effect pivotal movement of said lever.

7. A printing mechanism according to claim 2;

including feeding means for intermittently feeding a record medium between said printing means and said type-carrying member one space per printing cycle.

8. A printing mechanism according to claim 7;

wherein said feeding means comprises a pair of rotatable feed rollers having sandwiched therebetween and in frictional driving contact therewith the record medium, and electromagnetic means for electromagnetically rotating one of said feed rollers in an intermittent manner through a succession of angular increments to intermittently feed the record medium one space per angular increment of movement of said one feed roller.

9. A printing mechanism according to claim 1;

wherein said electromagnetic drive means includes stop pins positioned relative to said pair of pawls to limit the extent of driving movement of said pawls.