US3528368A - Device for initiation of the printing action on a high-speed printer - Google Patents

Description

United States Patent [72] Inventors Max Oberholzer, Liebefeld,

near Bern; Robert Locher, Schonbuhl; Heinz Brechbiihl, Bern,

.fiw tz r anst M [21] Appl. No. 698,481 [22] Filed Jan. 17, 1968 [45] Patented Sept. 15, 1970 [73] Assignee Hasler A.G.,

Bern, Switzerland,

a company of Switzerland [32] Priority Jan. 19, 1967 [3 3] Switzerland [31] No. 750/67 [54] DEVICE FOR INITIATION OF THE PRINTING ACTION ON A HIGH-SPEED PRINTER 6 Claims, 4 Drawing Figs. 52 U.S.Cl 101/93 [51] Int. Cl B41j 9/14, B41 j 9/16 [50] FieldofSearch 101/93,9l,

[56] References Cited UNITED STATES PATENTS 2,766,686 10/1956 Fomenko et al.

2,893,313 7/1959 Pekar et al 2,895,411 7/1959 Demer et al.

3,043,213 7/1962 Donabin 3,128,694 4/1964 Kittler 3,351,007 11/1967 Poland Primary ExaminerWilliam B. Penn AttorneyMichael S. Striker ABSTRACT: A high-speed printer including a rotating type drum, a plurality of strikers arranged to press, when actuated, a recording medium against a character on the periphery of the type drum, and actuating means for actuating selected strikers and including a cam drum having cams selectively movable between an active and an inactive position to actuate in the active position a selected striker.

IHI llllll 111 Patented Sept. 15, 1970 3,528,368

Sheet 1 of2 FIG.|

Patented Sept. 15, 1970 3,528,368

sneet 2 or2 DEVICE FOR INITIATION OF THE PRINTING ACTION ON A HIGH-SPEED PRINTER The present invention relates to an improved device for initiation of the printing action on a high-speed printer.

In high-speed printers constructed for high working speeds, continuously revolving type drums are frequently employed, whereof the length corresponds to the line width of the paper to be printed. A thrust hammer or striker for each .print or impression point, is situated adjacent the peripheryof the type drum. To print the characters, these strikers are impelled against a paper positioned between the type drum and the strikers. The strikers are so controlled, respectively triggered, in a timed sequence, that a full line is printed after each revolution of the type drum. The correct choice and co-ordination to the angular position of the type drum is established by means of an electronic control system which at the same time also controls the paper feed.

Stringent requirements are applied with respect to the driving system for the strikers of such printing mechanisms, since the impulsion frequency is very high, and a short period of contact between the striker and the paper must be obtained while the required impact energy must be generated. The division of these driving systems should moreover be kept sufficiently small so that impression points may be placed on each inch of width of the recording paper.

Electromagnetic driving systems are employed for accelerating the strikers in numerous known high-speed printers. The efficiency of these devices, however, is low, since it is difficult to generate the speed and momentum required for the strikers by means of electromagnets. Maintenance of the precise printing instant is also extremely difficult in such driving systems.

A triggering device is already known, in which a so-called impact wheel running synchronously with the type drum is employed as a mechanical energy storage device for accelerating the strikers. In the same, a coupling element is inserted from the outside at the desired instant, under control of a magnetic system, into the impact wheel, which causes the initiation of the printing action, inasmuch as a tooth of the impact wheel or gear is coupled with the striker and the impact wheel imparts the required energy to the striker.

In this initiating device, the coupling element is situated outside the energy storage device, i.e. is structurally separate from the same.

In the device according to the present invention for initiation of the printing action on a high-speed printer, the coupling element is transferred into the energy store, thereby obtaining a simple structure reliable in operation. This device is characterized in that parallel to the type drum a continuously revolving cam drum is provided, in which several cams are housed for each printing point, which may optionally be brought into the operating position by means of a magnetic system situated on the periphery of the cam drum, in which position they operate the strikers and thus initiate the printing action.

The characteristic features of the invention are fully disclosed in the following description and the accompanying drawing of a preferred embodiment of the invention in which:

FIG. 1 is a schematic perspective view of the device according to the present invention; and

FIGS. 2-4 are side views showing various elements of the device in successive positions.

In the initiating and printing device drawn diagrammatically and in perspective, the continuously revolving type drum built up from separate type discs, is marked I. On the periphery of each type disc are provided, for example, characters 2 for printing and an unoccupied space running past the striker during the period of paper feed.

Axially parallel to the type drum 1 is situated the equally continuously revolving cam drum 3, which is built up from separate cam discs 4. The cams for two consecutive impression points positioned adjacently in the impression line, are slidably arranged in radially extending grooves 14 formed in opposite end faces of the cam discs 4. In the example of the illustrated embodiment, nine cams 5 are incorporated per impression point or for each disc of the type drum, of which only four are shown completely in the drawing for the first impression point.

Since the number of characters 2 provided per impression point does not correspond to the number of cams 5, while a cam 5 must be co-ordinated with each character 2, the required correction is obtained by the transmission ratio between the type drum 1 and the cam drum 3, the cam drum 3 rotating correspondingly faster.

An electrically controllable coil 6 of an electro-magnet is incorporated on the outer periphery of the cam'drum 3 for each impression point. In order that the lateral distance between one impression point and the next may be kept as small as possible, the coils 6 are positioned staggered relative to each other on the periphery of the cam drum. By energizing the coil 6 of a-respective electromagnet, the cams 5 may selectively be moved radially outwardly to their operating position.

Ahead of each coil 6, in direction of rotation of the drum 3, is situated a return or restoring (50g 7 having a cam surface 7a, by means of which the cam 5 drawn out by the coil 6 is pushed back into the initial position. The corresponding coil 6 is ac-- .tivated by means of an electronic selection system, to initiate the printing action at an impression point. If the cadencer signal corresponds to the input signal of the required character, the coil 6 is energized during the time in which the brush 8 of the cadencer rotating with the type drum 1 brushes over a contact track 9a of the contacter disc 9, and the cam 5 situated under the pole piece 6a at this instant is moved radially outwardly into the operating position.

During continued rotation of the cam drum 1 in the direction shown by the arrow, the radially outwardly moved cam 5 strikes the corresponding striker segment 10 of a set of striker elements tumably mounted on a pin -15 and whose lower extremities are situated barely above the cam drum 3. The upper extremity of the struck striker segment is thereby flung against the type drum 1 respectively against the recording paper 13 situated between the striker segment and the type drum.

Since the weight of the striker segment 10 is relatively low, the mechanical energy stored in the cam drum 3, on impact of a cam, engenders a powerful acceleration of the striker segment in the direction toward the type drum. The impression is produced by impact of the striker segment 10 on the recording paper 13 respectively the type drum 1.

After impact on the type drum 1, the striker segment 10 rebounds, and is held in the initial position by a spring 16 fastened at opposite ends to a fixed pin 17 and to the striker segment against a damping element 18.

Before the radially outwardly moved cam 5 reaches its coil 6 again during further rotation of the cam drum 3, it is engaged by the restoring cam surface 7 and pushed back into the initial position. The cam 5 is held in its initial position by means of a spring-loaded detent pin or the like 11, which engages in a groove 5a formed in the cam 5.

As already stated, the coils 6 and the restoring cam surfaces 7 are not positioned in a row but staggered relative to each other on the periphery of the cam drum 3, and a compact form of construction being obtained thereby for this initiating device.

The coils and restoring cam surface are arranged in four groups, each group on a bridge element 12, for example one group for the first, fifth, ninth, 13th, 17th and 21st impression points. 0f the four bridge elements 12 incorporated in the example of embodiment, only two are illustrated in the drawing. The staggered arrangement of the coils 6 on the periphery of the cam drum 3 has the result that the so-called access period for a specific numeral 2, Le. the time required on selection of the character for rotary displacement of the type drum to bring the character which is to be printed to the impression point, is not of the same magnitude at all impression points. For equalization of the access periods, the type discs are also arranged in groups and positioned peripherally staggered on the spindle of the type drum.

As apparent from the drawing, the coils 6 are distributed on the periphery of the cam drum 3, in such manner that the same may simultaneously actuate a second striker system 110 respectively a second printing mechanism. The striker segments 110 of the second striker system are turnably mounted on a pin 115 and held in their initial positions by springs 116 carried at one end by pin 117 against damping element 118.

For adaptation of the access periods, the type discs incorporated in the type drum 101 in this printing mechanism are correspondingly installed in staggered arrangement.

We claim:

1. In a high-speed printer, in combination, a type drum rotatable about its axis, said type drum having on its periphery at least one set of characters arranged circumferentially spaced from each other substantially in a plane normal to the axis of the drum; a cam drum rotatable in a predetermined direction about an axis substantially parallel to that of said type drum and in correlation to the rotation of the latter and including at least one set of cams circumferentially spaced from each other and each movable between an active position and an inactive position; at least one striker; means mounting said striker movable in said plane toward and away from the periphery of said type drum with a portion of said striker located in the path of a cam located in said active position so as to be engaged by the latter during rotation of said cam drum and to be moved toward the periphery of said type drum so as to move a recording medium located between said striker and the periphery of said type drum into engagement with a character; moving means cooperating with said cams to move a selected cam of said set of cams from its inactive to said active position; and restoring means located in direction of rotation of said cam drum ahead of said moving means for moving any cam which is in said active position back to its inactive position, said restoring means comprising a stationary cam face arranged to cooperate with a cam in active position to move the latter to its inactive position.

' 2. A structure as defined in claim 1, wherein said striker comprises a segment pivotally mounted on said mounting means about an axis substantially parallel to that of said type drum.

3. A structure as defined in claim 1, and including means for yieldably maintaining said cams in said inactive position and comprising a spring loaded detent means for each cam.

4. In a high-speed printer, in combination, a type drum rotatable about its axis and having on its periphery a plurality of sets of type characters, the type characters in each set being arranged circumferentially spaced from each other substantially in a plane normal to the axis of said drum, and the plurality of sets being arranged in a plurality of axially displaced planes; a cam drum rotatable in a predetermined direction about an axis substantially parallel to that of said type drum and in correlation to the rotation of the latter and including a plurality of sets of cams. the cams of each set being circumferentially spaced from each other and said set of cams being arranged in said cam drum axially displaced from each other, each cam being movable in radial direction between an active position and an inactive position; a plurality of strikers; means mounting said strikers respectively movable in said planes toward and away from the periphery of said type drum with a portion of each striker located in the path of a respective cam when the latter is in said active position so as to be engaged by the respective cam during rotation of said cam drum and to be moved toward the periphery of said type drum so as to move a recording medium located between the engaged striker and the periphery of said type drum into engagement with a character; moving means cooperating with said cams to move a selected cam of said sets of cams from its inactive to its active position; and restoring means located in direction of rotation of said cam drum ahead of said moving means for moving any cam which is in said active position back to its inactive position, said moving means and said restoring means for said sets of cams are staggered about the periphery of said cam drum.

5. A structure as defined in claim 4, wherein said cam drum comprises a plurality of coaxial discs abutting against each other with opposite end faces thereof, each of said discs being formed in each of said end faces thereof with a plurality of radially extending grooves for guiding adjacent sets of cams movable between said active and said inactive position.

6. A structure as defined in claim 4, and including a second plurality of strikers arranged circumferentially spaced from said first mentioned plurality of strikers adjacent to the periphery of said cam drum and a second type drum arranged for cooperation with said second plurality of strikers, said restoring means for each set of cams being located in the direction of movement of said cam drum ahead and closely adjacent to the respective moving means.

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