US3233540A - Line-at-a-time printer - Google Patents

Description

Feb. s, 1966 H GROTTRUP 3,233,540 LINE-AT-A-TIME PRINTER 2 Sheets-Sheet 1y Filed April 25, 1965 n 1 1 r 1 c I NVEN TOR.

ATTORNEY Feb. 8, 1966 H. GRo'r-rRUP LINE-AT-A-TIME PRINTER 2 Sheets-Shea?l 2 Filed April 23, 1965 Il Il Il Il Il Il Il Il Il Il Il Il Il Il /l Il Il n INVENTOR.

/EML/' GROTTRUP BY @w 6% .ATTORNEY Vfor lthe printing purpose.

United States Patent O 3,233,540 LlNE-A'I`ATIME PRINTER Helmut Grottrup, Pforzheim, Germany, assignor to International Standard Electric Corporation, New York, N.Y., a corporation of Delaware Filed Apr. 23, 1965, Ser. No. 450,465 3 Claims. (Cl. lill-93) This application is a continuation-inpart of my prior application Serial No. 153,144 filed November 17, 1961, now abandoned.

The present invention relates to a line-at-a-time printer. Such types of printing devices have been known for some time in the relevant art in the form of mosaic printers, in which the* characters are constituted by individual points, e.g. by an array consisting of 5 times 7 point elements. Various ways have already been proposed for producing the characters. One simple way consists in assembling 35 wires in the form of a writing head, and bundling these wires in such a way thattheir ends form an approximately plane surface, the size of which corresponds to that of the characters to be printed. Independently of one another, these wires can be pushed out of this surface and against the printing surface. There are two ways of selecting the respective wires necessary for the printing purpose: either each individual wire is actuated by an electromagnet of its own, or the entire wire pack is pushed against a perforated template which permits the passage of only those wires which are required Instead of the perforated ternplate it is also possible to use a template comprising a certain arrangement of bosses. In this case, the template is adjusted in such a day that the wires to be printed oppose the bosses; thereupon the template is pushed against the wire pack. In order to enable the simultaneous printing of several characters, a corresponding number of writing heads may be juxtaposed. Since in general the characters are required to be arranged more closely to each other than the writing heads with their actuating mechanisms can possibly be arranged, one known proposal is to provide several heads, of which each one is assigned to several printing positions. In this case the printing is effected simultaneously. After the printing, the writing heads arranged in one line are displaced side ways, so that the next characters can be printed in the same line.

Instead of prin-ting the m-times-n point array as a whole, it may also be built up in a row-wise fashion. In this case the writing heads only consist of either m or n wires respectively, and either the writing head is moved over the paper, or the paper is moved past the writing head. The actuation of the printing wires is effected by individually energized electromagnets; Also in this case several Writing-heads may be arranged in such al way that simultaneously either several or all characters of one printing line can be built up. The row-wise construction of the characters is preferred because the paper can be moved continuously past the heads, thus permitting attainment of extremely high operating speeds. However, since the actuating magnets occupy a certain space in the length or width of the printing line, which cannot be` reduced, the characters cannot be printed as closely to each other as would be desirable from the legibility point of view. This disadvantage could be eliminated by arranging the writing heads in several staggered rows, but this would entail a considerable expenditure, and an enlargement in size of the printing device.

In particular, the present invention relates to a wire printed of the last mentioned kind, a line-at-a-time printer in which the characters of one printing line are composed in a row-wise manner from above to below, but in which a continuous, that is, uninterrupted printing of the charac- ICC ters can be carried out with a minimum thickness of the printing wires. In `the conventional manner, printing mechanisms can be used in which the wires are not assembled in printing heads, but are individually controllable by the action of electromagnets.

The general idea of the invention consists in providing onesingle electromagnet for the actuation of all typeprinting elements, and in designing the individual typeprinting elements to act as the armature of this electromagnet which is provided in common to all type-printing elements or groups of type-printing elements, and in designing the armatures, in turn, as electrically conductive angular levers each consisting, in the direction of the lines, of a thin sheet of metal, with its center of rotation lying outside the electromagnet, so that upon energization of the electromagnet, a lug provided at the angular lever is pressed against the printing ribbon. lFor selecting the type-printing elements to be actuated, there is provided an electrostatic or magnetic device which, upon energization, has a retarding effect upon the angular levers and thus controls the selective printing operation of the typeprinting elements.

The action of frictional forces, produced in electrostatic clutches, is know per se. The electrostatic force may therefore be produced in any known manner. The resetting of the type-printing elements can be effected witl the aid of a mechanical spring; however, it is more appropriate to provide a magnetic resetting in such a way that the angular levers are reset to normal by a second common magnet after the printing process has been performed` The invention will now be explained in detail with reference to exempliiied embodiments shown in FIGS. 1-4 of the accompanying drawings, in which:

FIG. l is a side view of Ia unitary structure containing ve type-printing elements and showing the electrostatic control arrangement according to the invention;

FIG. la is an end view of the structure o FIG. 1;

FIG. 2 is a section taken on the line A-A of FIG. l;

FIG. 3 is a section taken on the line B-B of FIG. l; and

FIG. 4 shows a modified type of embodiment of the type-printing element according to the invention.

In `the drawings the cross-sections .are not shown in a true scale, but, especially in the dimension extending in parallel rela-tion to the line, in an extremely distorted fashion, in order to enable a better understanding of the detail-s.

It is assumed that for each character there are required five type-printing elements, and two type-printing elements for each space, so that altogether seven times more type-printing elements are required than characters to be written in one line. The individual elements 1 are pivotably .arranged on a shaft 2 which is common to all elements. On the upper right-hand side there is provided a lug 3 forming a printing point which, after a corresponding movement of the type-printing element, is adapted to hit the ink ribbon 4. The lower parts of all elements 1 project into a space which is defined by two Ymagnets 5 and 6 corresponding to the length of the line.

These magnets are manufactured in the conventional manner from two pole pieces with intermediately arranged wound cores. The magnet 6 is the reset magnet, that is, the magnetic spring for resetting all type-printing elements to normal. The magnet 5V operates as a printing magnet to bring all type-printing elements against the limit stop in the printing plane. The type-printing elements, in their lower portion 7, are of a stronger design than in their upper portion 8. The portion 8 is inserted in a silghtly movable way into a gap between two foils of insulating material 9. On the other side of each of these two insulating foils 9 are two electrically conductive foils which are respectively followed by a further insulating foil 11. lThe foils 10 may also be designed as met-al coatings of the foils 9. Between the two foils 9, and in the space which is not occupied by the' portion 8 of the type-printing elements, there is arranged -a still thicker sheet-metal member i2 which is provided with a soldering terminal 13. p They solderingterminals of successively following sheet-metal members 12 are staggered, as shown in FIGS. 1 and 1a. .The metal foils 10, or the corresponding coatings, for each of the type-printing elements are conductively connected to the connecting sheetmetal member 12 by way of slots provided in the foils 9, or by corresponding bosses or the like provided on the connecting sheet-metal member 12. The foil packs associated with the portions 7, 8 of the type-printing elements are separated from one Ianother by intermediate members 14, and are arranged on the shaft 15, 16y in an insulated manner. This shaft chiefly facilitates the centering of the Whole block. The actual assembly is effected by the shafts 17 and the intermediate layer members 18.

This novel type of line-at-a-tirneprinter operates with a continuous paper feed, 4as follows: Firmly coupled to the feed shaft is a switching Wheel arrangement which I'alternately energizes the magnets 5 and 6. For the control of these magnets and for selectively controlling the type elements electro-statically, I have shown a switching wheel comprising three switching commutators 19, 29, and 21. Each of these commutators has alternately insulating Iand conducting circumferential portions and cooperating wipers. The commutators 19 and 2o are connected to ground. The former controls the resetting of the type elements by a wiper 21 which is connected t-o the coil of the reset magnet 6, the other end of the coil being connected to battery. The conducting portions ofthe commutator 19 are shown larger than the insulating portions to give suicient time for the electrostatic foils to be discharged and individually charged while the type elements are held in the reset position.

The commutator Zit has been shown with the insulating portions larger than the conducting portions, and a Wiper 22 is connected to the coil of the magnet 5 the other end of which is connected to battery. The wiper 22 is on a conducting portion of the commutator when the wiper 21 is on an insulta-ting portion of the commuft'ator 19. Upon energization o-f the magnet 5, all typeprinting elements are caused to hit the printing surface for producingthereon a mosaic point, provided that they are not prevented from performing this movement by the action of the electrosta-tic friction between the foils. During the reset, which is effected by the magnet 6, the metal foils or coatings 1t) are. first ofv all discharged via the soldering terminals 13 and Wipers 23, 24, 25, 26, and 27 which are at that moment in contact with the conducting portions of commutator 2d, and are thereupon individually charged. For charging the individual foils 10 and connected members 12, the coinmutator 21 may be used; This com-mutator is insulated from the common shaft by insulating sleeve 28 and is connected to battery. A wiper 29 rests on a conducting portion of the commutat-or 21 as long as the reset magnet is operated.0 Itis connected-to switches 30 by means of which selected' ones of the foil'packs can be connected to battery during this time andthus charged. The non-charged foilpacks permit the free movement of the portionsl 7, 8 of thetype-printing element when the magnet 5 is next operated.- The charged foil packs prevent this movement on account'of the friction appearing between the foilsV and the portion 8 of the type-printing element, and caused .by the electrostatic` force. The type-printing elements themselves are in this case'A always applied to ground potential via the common shaft 2.

FIG. 4 shows another possible embodiment of a typeprinting element, wherein the elements are provided with a lower inertia than in the case of the already described Cit type of printer. This is of advantage in cases where the printing speed is very high.

In principle, however, neither this type-printing element nor the actuation thereof differs from what has been described hereinbefore. Thus, also in this case, the individual elements 1 are capable of being swivelled about the common shaft 2. In this case, however, the two ele'ctromagnets are arranged in a different way, i.e. in such a way that the portion 8 of the type-printing elements performs a lateral movement as indicated by the double-ar row 19 (FIG. 4). Accordingly, the travel of the typeprinting elements is smaller than in the embodiment shown in'FIGS. 1-3, wherein the type-printing elements are pulled forward out of the foil pack.

The electrostatic operation in the second example bears a resemblance to that shown in the first example and therefore does not require any further explanation.

The particular advantage of this novel type of printer over the conventional types of printers resides in the fact that a mechanical spreading of `structural elements is avoided. This is made possible by the employment of electrostatic forces. This, in turn, has the advantage that the friction-producing forces are only used to perform aretarding process, thusy restricting the wear of the f rubbing surface to a minimum.

The basic arrangement as shown in the drawings may b-evfuther extended from the technological point of View. Thus, under certain circumstances, it may be appropriate to construct the electrostatic retarding device from simple stampings which, at the respective points, are coated with a highly insulating and wear-resistant lacquer. The portions 7 and 8 of the type-printing element may also be composed of a relatively thin `sheet-metal member in the middle and of two stuck-on sheet-metal members on either side thereof for strengthening the portion y of the element l.

While have described the principles of my invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of my invention as set forth in the accompanying claims.

Iiclaim:

1. A printing apparatus comprising:

a row ofv electrically conductive printing elements mounted side-by-side for movement transversely to said row from a given rest position to a given active printing position, each said element comprising a printing point projection, a iirst control portion, and a second control portion, each of said second con'- trol portions having a iiat surface parallel to the plane in Which the printing clement moves; first means extending parallel to said row adjacent said first control portions and operatively coupledfthereto for applying forces, when energized, to said elements tending to move said elements from ythe said rest positions to the saidactive printing positions thereof; second means extending parallel to said row adjacent said iirst control portions and operatively coupled thereto for applying forces, when energized, to said elements tending to restore said elements to the said rest positions;

a series of control members arranged in a row parallel toV said row of elements and operatively coupled respectively thereto for applying frictional restraining Y forces, when energized, tothe second portions of respectiveV ones of said printingelements in the rest positions thereof, each of said series of control members comprising a foil construction containing a layer of electrically conducting material positioned closely parallel to'the iiat surface of said element and separated therefrom by a layer of insulating material;

means for alternately energizing said first and second i means 5 and means operatively connected to said energizing means and operative only when said second force-applying means is energized for selectively energizing said control members to apply frictional forces to selected vones of :said second portions, thereby preventing `the corresponding printing elements from moving tov the active printing position.

2. Printing apparatus, according` to claim 1, wherein the said control-rnember-energizing means includes:

means for applying a common electrical potential to all of said printing elements;

a series of conductive terminal members electrically connected to the conductive layers in the foil construction of corresponding ones of said control members; and

means electrically insulating said terminal members from each other.

3. Apparatus, according to claim 1, wherein each said foil construction comprises two symmetrically disposed foil members, one on each side of the second control portion of the associated printing element which, when energized by said energizing means, create a force of electrostatic attraction between said foil members and said second portion of -said printing element.

- References Cited by the Examiner UNITED STATES PATENTS 2,025,123 12/1935 Rahbek 317-144 2,659,652 11/1953 Thompson lOl-109 2,976,801 3/1961 Dirks 10d-93 2,990,767 7/1961 Deiner et al. lOl-93 WILLlAM B. PENN, Primary Examiner.

Claims (1)

1. A PRINTING APPARATUS COMPRISING: A ROW OF ELECTRICALLY CONDUCTIVE PRINTING ELEMENTS MOUNTED SIDE-BY-SIDE FOR MOVEMENT TRANSVERSELY TO SAID ROW FROM A GIVEN REST POSITION TO A GIVEN ACTIVE PRINTING POSITION, EACH SAID ELEMENT COMPRISING A PRINTING POINT PROJECTION, A FIRST CONTROL PORTION, AND A SECOND CONTROL PORTION, EACH OF SAID SECOND CONTROL PORTIONS HAVING A FLAT SURFACE PARALLEL TO THE PLANE IN WHICH THE PRINTING ELEMENT MOVES; FIRST MEANS EXTENDING PARALLEL TO SAID ROW ADJACENT SAID FIRST CONTROL PORTIONS AND OPERATIVELY COUPLED THERETO FOR APPLYING FORCES, WHEN ENERGIZED, TO SAID ELEMENTS TENDING TO MOVE SAID ELEMENTS FROM THE SAID REST POSITIONS TO THE SAID ACTIVE PRINTING POSITIONS THEREOF; SECOND MEANS EXTENDING PARALLEL TO SAID ROW ADJACENT SAID FIRST CONTROL PORTIONS AND OPERATIVELY COUPLED THERETO FOR APPLYING FORCES, WHEN ENERGIZED, TO SAID ELEMENTS TENDING TO RESTORE SAID ELEMENTS TO THE SAID REST POSITIONS; A SERIES OF CONTROL MEMBERS ARRANGED IN A ROW PARALLEL TO SAID ROW OF ELEMENTS AND OPERATIVELY COUPLED RESPECTIVELY THERETO FOR APPLYING FRICTIONAL RESTRAINING FORCES, WHEN ENERGIZED, TO THE SECOND PORTIONS OF RESPECTIVE ONES OF SAID PRINTING ELEMENTS IN THE REST POSITIONS THEREOF, EACH OF SAID SERIES OF CONTROL MEMBERS COMPRISING A FOIL CONSTRUCTION CONTAINING A LAYER OF ELECTRICALLY CONDUCTING MATERIAL POSITIONED CLOSELY PARALLEL TO THE FLAT SURFACE OF SAID ELEMENT AND SEPARATED THEREFROM BY A LAYER OF INSULATING MATEIAL; MEANS FOR ALTENATELY ENERGIZING SAID FIRST AND SECOND MEANS; AND MEANS OPERATIVELY CONNECTED TO SAID ENERGIZING MEANS AND OPERATIVE ONLY WHEN SAID SECOND FORCE-APPLYING MEANS IS ENERGIZED FOR SELECTIVELY ENERGIZING SAID CONTROL MEMBERS TO APPLY FRICTIONAL FORCES TO SELECTED ONES OF SAID SECOND PORTIONS, THEREBY PREVENTING THE CORRESPONDING PRINTING ELEMENTS FROM MOVING TO THE ACTIVE PRINTING POSITION.

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