US3382963A

US3382963A - Printing apparatus with no-print feature

Info

Publication number: US3382963A
Application number: US573020A
Authority: US
Inventors: Jr Walter O Cralle; George T Slaughter
Original assignee: International Business Machines Corp
Current assignee: International Business Machines Corp
Priority date: 1966-08-17
Filing date: 1966-08-17
Publication date: 1968-05-14
Anticipated expiration: 1985-05-14
Also published as: ES344148A1; GB1187507A; DE1611445B1; BE699675A; SE331286B; NL153803B; NL6710363A; FR1529400A; CH454183A

Description

May 14, 1968 w. o. CRALLE, JR ET AL. 3,382,963

PRINTING APPARATUS WITH NO-PRINT FEATURE Filed Aug. 17, 1966 3 Sheets-Sheet l INVENTORS. WALTER 0. CRALLE, JR. GEORGE T. SLAUGHTER Buy/4.49% A ATTORNEY.

1968 w. o. CRALLE, JR. ET AL 3,382,963

PRINTING APPARATUS WITH NO-PRINT FEATURE Filed Aug. 17, 1966 5 Sheets-Sheet 2 FIG. 6

ET AL 3,382,963

3 Sheets-Sheet 3 Emma 363m;

W. O. CRALLE, JR.

May 14, 1968 PRINTING APPARATUS WITHNO-PRINT FEATURE Filed Aug. 17. 1966 s s mm on s s a n f 23 E 5:5: :5 EWE1 E A a 2 :5 gfimsm ZOE: :2 mew E03: EEG T 5% Ea OE 558 ;E

United States Patent 3,382,963 PRINTING APPARATUS WITH NO-PRINT FEATURE Walter 0. Cralle, Jr., Georgetown, and George T.

Slaughter, Lexington, Ky., assignors to International Business Machines Corporation, Armonk, N.Y., a corporation of New York Filed Aug. 17, 1966, Ser. No. 573,020 12 Claims. (Cl. 197-16) ABSTRACT OF THE DISCLOSURE The invention relates to control mechanism for a printer to establish several degrees of print impression, as well as a No Print condition under certain circumstances, such as a space operation. A print head is actuated against a document with several degrees of impression controlled by a print cam. A No Print condition is established by a No Print cam. The action is determined by the position of a cam roller that is moved back and forth adjacent one of the cams by a pulley and cable. The printer keyboard has character keys, a spacebar, and a No Print key. The keys operate velocity stops of differing lengths which control the extent of movement of a cam follower and therefore, the positioning of the cam roller. The character keys establish low, medium, and high print velocities. When the spacebar is operated, all of the velocity stops are moved out of contact with the follower and the roller is then'positioned adjacent the No Print cam. Another key is operated manually to retain the stops out of print control position, thereby establishing a No Print condition for an extended period of time. The apparatus also has undershoot and overshoot control means associated with the cam roller. A pinwheel memory stores escapement values.

Background of invention-field, and prior art The invention has particular utility in a typewriter with a single element print head, such as that disclosed in US. Patent 2,879,876 to L. E. Palmer et al., entitled, Single Element Printing Machine, and in US. Patent 2,919,002 to L. E. Palmer, entitled, Selection Mechanism for a Single Printing Element Typewriter.

A prior print impression control mechanism for a typewriter of this nature has been disclosed in US. Patent 3,239,049 to W. F. Voit, Jr., entitled, Impression Control Mechanism Automatically Selecting One of a Plurality of Cams. 7

A related case of interest is the pending application for US. Patent Ser. No. 311,373, now US. Patent 3,346,- 086, with W. O. Cralle, Jr., et al., as inventors, and entitled Single Element Typewriter, filed Sept. 25, 1963, and assigned to the same assignee as the present invention.

The two Palmer patents set forth a typewriter having a single element print head which moves adjacent a document mounted on a stationary platen; that is rotated and tilted for selecting individual characters for printing just prior to actuation against the document during successive printing cycles. A typewriter of this nature is manufactured by International Business Machines Corporation, New York, N.Y., and is sold under the trademark Selectric. The Selectric typewriter is described with considerable detail in the IBM Customer Engineering Instruction Manual on the Series 72, Form No. 2414032, copyright 1961. The typewriter is further adapted for input/output (I/O) operations as disclosed in the IBM Customer Engineering Instruction Manuals Selectric I/O Keyboard Printer, Form No. 241-5159, copyright 1965,

In the basic Selectric typewriter described in the Palmer patents and in the manuals, all characters on the print head impact upon the printed page at approximately the same velocity when the print head is actuated, and consequently, each character strikes the document with about the same force. The mechanisms are adjusted to print the majority of characters with the proper impression, the result being that small space area characters, such as the punctuation characters may impress the paper somewhat harder than desired resulting in side printing and possible paper penetration. An important inventive arrangement is described in the Voit patent for establishing varying degrees of impression for the print head prior to printing to insure a more uniform impression on a document. The Voit mechanism includes a plurality of cam elements that are selectively positioned in the printing drive train just prior to printing actuation in each cycle with each cam effecting a different measure of force in driving the print head, depending upon the character just selected. In this manner, the characters having small areas strike the document with somewhat less force while the larger characters, such as M and W, strike the document with a greater force.

A print impression mechanism, such as the Voit mechanism, lends itself admirably to incorporation in a justifying typewriter of the type disclosed in the patent to Cralle et al. The Cralle et al. typewriter has particular utility in the preparation of articles with justified lines for use in newspaper work where it is essential that the printing of characters be performed with uniformity and with efficiency. The Cralle et a1. patent describes a proportional escapement mechanism including settable pins arranged in a pin wheel that serve as a memory unit for remembering the past escapement history of an individual line, thereby enabling a typist to backspace and forward space to effect the correction of typographical errors and for revising a line to insure that the line length meets a predetermined standard length that is required for a news article under preparation.

During operation of the Cralle et al. apparatus, and according to the present invention, a typist may wish to type a line of copy in a No Print" operation during which the single element print head is escaped along the platen as individual characters are selected and functions performed, but the print head is not actuated against the platen and, therefore, no printing occurs. The procedure is followed in order to determine how much space remains in a particular line, whereupon the operator distributes the space as evenly as possible in the spaces occurring between words in the line. Subsequently, the equipment is returned to a Print mode to efl'ect the actual printing of characters with the distribution of the excess space being automatically performed so that the line is completely justified and of exactly the required predetermined length.

Under such circumstances, it is desirable to operate functional mechanisms, such as spacebar mechanisms and various selection and printing mechanisms associated with the single element print head to effect electrical or mechanical storage of escapement values related to the functions or individual characters, as an example, but without actually operating the print head.

Even when the print head is actuated during the final printing of a line, it is sometimes desirable to operate mechanisms associated with the print head, such as the spacebar and escapement mechanisms in common with the printing mechanisms, but without actually operating the print head itself. The latter operation may be referred to as a cyclical No Print operation since it occurs selectively on a cyclical basis, rather than over an extended perior of time, as under operator manual control.

Objects Accordingly, it is an object of the present invention to provide printing apparatus with a selectively operable print control mechanism.

Another object of the invention is to provide a print control mechanism that lends itself to automatic and manual control.

A still further object of the invention is to provide a print impression control apparatus that is operable cyclically, on demand, or continuously, as required.

A still further object of the present invention is to provide print control mechanism for a single element printing apparatus.

A further object of the invention is to provide a print control met hanism that is selectively operated for char acter and function selections.

Also, an object of the invention is to provide a print control mechanism that is operable over a wide range of conditions, from a No Print condition to a high velocity condition.

Summary In order to accomplish these and other objects of the invention, a printing apparatus is provided with a control mechanism that is selectively operable during individual cycles of printing, that is conditioned, under certain functional conditions, such as spacing, to establish a No Print operation, and that is further operable under manual operator control to be conditioned to a No Print state for as long a period as the operator may require. The apparatus performs its functions in an extremely efficient fashion with high speed and accuracy.

The foregoing and other objects, features, and advantages of the invention will be apparent from the following more particular description of a preferred embodiment of the invention as illustrated in the accompanying drawings.

Description 07 the drawings In the drawings:

FIG. 1 illustrates printing apparatus that incorporates a print control arrangement according to the present invention.

FIG. 2 is a top elevation of certain key mechanisms associated with the printing apparatus of FIG. 1.

FIG. 3 is a front elevation of a single element print head and associated print driving mechanisms.

FIG. 4 is a sectional view of various cam elements taken on the line 4-4 in FIG. 3.

FIG. 5 illustrates a portion of a print control mechanism on the line 55 in FIG. 1.

FIG. 6 illustrates key controlled mechanisms associated with the spacebar and escapernent in the printer of FIG. 1.

FIG. 7 illustrates key oriented mechanisms associated with character selection in the printer of FIG. 1.

FIG. 8 illustrates a manual control for effecting No Print conditioning of the printing apparatus of FIG. 1.

FIG. 9 is a sequence chart illustrating in composite form, various operating conditions encountered in the apparatus of FIG. 1 during a cycle of operation.

Detailed description FIG. 1 is a diagrammatic representation of a printing apparatus according to the present invention. The apparatus includes a single element print head I mounted on a rocker 2 retained in a carrier 3 for movement adjacent a platen 4 having a document 5 positioned for printing. Print head 1 is selectively tilted and rotated by selection mechanisms shown in the Palmer patents previously mentioned and controlled by character keybuttons (keys), such as

keybuttons

10, 11, and 12. The

key buttons

10, 11, and 12 are representative of a usual typewriter keyboard that also includes a spacebar 14. In addition to the other keys, the keyboard has a No Print key 15.

FIG. 2 is a plan elevation of the

character keys

10, 11, and 12, illustrating associated daubers 24, 3t and 31 for operating related interposers 2t), 21, 22. spacebar 14 is shown with dauber 32 and interposer 33.

Following depression of one of the keys and the tilting and rotating of the print element 1, the rocker 2 is actuated by means fully disclosed in the Palmer patents to impress the selected character on document 5 through ribbon 6.

As taught in the Cralle et al. application, the carrier 3 engages a lead screw 18 that is rotated to impart a movement of carrier 3 from left to right in FIG. 1 as printing proceeds and in accordance with the proportional escapement value required for each character or spacing operation, as controlled by mechanisms in the Cralle et al. apparatus, said mechanisms being shown and designated 43 in FIG. 1 of the present case. As individual characters are selected and spacing occurs, clevis links 66, 77, and 86 are selectively operated to actuate pin setting members in the block 41 for setting pins 35 in a memory wheel 26, to thereby store the escapement history of each line as printing progresses. Pins 35, when they are set, control the reverse movement of carrier 3 in a backspace direction, as well as the forward spacing of carrier 3, and enable the arcuate positioning of print head 1 in relation to previously printed characters in order to insure accurate corrections.

Associated with the character keys 1t), 11, and 12 are

interposers

20, 21, and 22, respectively. In order to insure clarity of the illustration of FIG. 1, not all of the elements associated with each of the character keys or the spacebar key are shown. However, a typical controlling mechanism for a character key is illustrated in FIG. 7, while the spacebar elements are shown in FIG. 6. The typical character key, such as key 10, and its associated mechanism will first be described. In FIG. 7, depression of key 19 moves key lever 23 with associated dauber 24 downwardly. Dauber 24 contacts an extension a on interposer 20 and thereby moves interposer 20 downwardly. Arranged under all of the interposers is a cycle clutch bail 25. Actuation of any of the interposers downwardly moves the cycle clutch bail 25 downwardly and through mechanism shown in the Palmer patents operates a cycle clutch 46 for rotating a filter shaft 27 to effect operation of the various mechanisms in the printer. Filter shaft 27 is shown in FIGS. 1, 6, and 7. When cycle clutch 46 is tripped, filter shaft 27 rotates in the direction indicated by arrow 28, FIGS. 1, 6, and 7. The filter shaft is rotated 180 during any cycle of operation and a

blade portion

27a or 27b is disposed adjacent the ends of the interposers insuch a manner that the depressed interposer is engaged by the blade during its movement, thereby imparting a movement of the interposer toward the front of the printing apparatus which is generally to the right in FIG. 1 and to the left in FIGS. 6 and 7. Actuation of a character interposer by the filter shaft effects engagement of lugs such as lugs 20b on interposer 20, FIG. 7, with bail members 29 that are effective to determine the extent of rotation and tilting of print head 1 for positioning the desired character opposite the printing position prior to the rocking of print head 1 toward document 5.

In FIG. 6, spacebar 14 is arranged for movement downwardly by cooperation of a key stem 17 with a spacebar cam 36 and an associated stabilizing link 37. Movement of spacebar 14 downwardly rotates spacebar cam 36 counter-clockwise to act against a link 38 that is associated with a spacebar key lever 40 by pivotal mounting at 39. As is the case in most electrical typewriters, spacebar 14 can be depressed for a single spacing operation or can be depressed further for a repeat spacing operation. The dauber 32 is mounted on key lever 40 in association with the repeat/non-repeat pawl 18 for elfecting the desired space repetition. Associated with the key lever and the pawl 18 is the spacebar interposer 33 with an interposer latch pawl 45. The depression of spacebar 14 moves key lever 40 downwardly so that extension 32a on dauber 32 contacts the extension a of the latch pawl 45. This moves the spacebar interposer 33 downwardly, which thereupon moves the cycle bail 25 down to trip the cycle clutch 46, FIG. 1, and to thereby effect rotation of the filter shaft 27. The rotation of filter shaft 27 moves interposer 33 to the left in FIG. 6, and by mechanisms shown as 43, FIG. 1, and fully described in the Cralle et al. application effects a spacing operation.

Print impression control during character selection As individual characters are selected by the depression of

keys

10, 11, and 12, a print impression control mechanism shown in perspective in FIG. 1 and in other respects in FIGS. 3-5, is effective to establish the proper printing velocity in accordance with the area of each character so that a desirable impression on document 5 is achieved. Mounted for rotation with filter shaft 27 is an impression control cam 50, FIGS. 1 and 5. Impression control cam is adapted for 180 rotation during each printing cycle and operates against an impression cam follower 51 having a roller 52 co-acting with the cam 50. Impression cam follower 51 is pivotally mounted at 53. Cam follower 51 has an extension 51a that is arranged in proximity to ahigh velocity stop 55, a medium velocity stop 56, and a low velocity stop 57.

The velocity stops just noted are effective to control selection of a high, medium, and low velocity portion of a print cam 60, FIGS. 3 and 4. Associated With print cam is a print cam follower 61 with roller 62 engaging the print cam 60. Roller 62 is mounted for sliding movement in a slider assembly 64 having an associated slider yoke 65. For clarity, the various print cam and roller elements are shown separated in FIG. 1. The actual relationship of the elements is illustrated in FIG. 3. Reference is made to the Palmer patents and to the Selectric manuals for a description of the printing action with the rocking of rocker 2 under control of print cam follower 61. The print cam follower 61 is operated in the present instance a predetermined amount that is variable depending upon the size of the character to be printed. It is assumed that the key 10 selects a comma for printing, that key 11 selects an upper case B or a lower case b and that key 12 selects an upper case W or a lower case w.

The individual characters for

keys

10, 11, and 12 are assumed to require low, medium, and high velocity printing, respectively. The print cam follower roller 62 is normally positioned adjacent the portion 60:: of the print cam 60 and if it remains in this normal position, a relatively high velocity of print head 1 is established during printing. To establish a medium velocity, roller 62 is moved adjacent the portion 60b which imparts a medium velocity to print head 1 during printing. In order to print at a relative low velocity, roller 62 is moved adjacent the portion 600 of print cam 60 which operates the print cam follower sufliciently to impart a low velocity to print head 1 during printing.

Printing of character with high velocity Assuming that the key 12 for the character W is depressed, filter shaft 27 is rotated by cycle clutch 46 and concurrently the impression control cam 50 is also rotated to move the impression cam follower 51 in the direction indicated by arrow 70, FIG. 5. Impression cam follower 51 moves in the direction of arrow an amount that is determined by the velocity stops 55, 56, and 57. The character W requires a high velocity and it is necessary to retain print cam roller 62 adjacent the high velocity portion 60a of print cam 60. In a high velocity situation, all of the velocity stops remain in the condition shown in FIG. 5 so that velocity stop 55 is in position to contact extension 51a of the impression cam follower 51 during its movement in the direction indicated by arrow 70. Follower 51 has a second extension 5112 that is connected to a link 72 by a clevis 73. Link 72, in turn, is attached to one arm of a bell crank 74 that is pivoted at 75, FIG. 1. The other arm of bell crank 74 is attached by link 76 and clevis 47 to a tape pulley lever 78. Lever 78 has a pulley 79 with an associated velocity tape 80. Velocity tape 80 is routed around pulley 79 and another pulley 81 with the ends of velocity tape 80 attached to

velocity tape connectors

82 and 83 associated with the velocity slider assembly 64. Pulley 81 is mounted for rotation on a bracket 85 and maintained in a fairly fixed location throughout operation of the apparatus. Pulley 79 on the other hand, is movable back and forth as indicated by arrow 89 toward and away from pulley 81 as a result of the pivoting of the tape pulley lever 78 about the pivot point 90. An adjusting screw 92 is initially positioned with

jamb nuts

93 and 94 to position yoke 65 in the proper zero reference position with respect to the high velocity portion 60a of print cam 60.

As may be deduced, the retention of the velocity stops 55, 56, and 57 in the position shown in FIG. 5 limits the movement of impression cam follower 51 and by linkages just described retains pulley 79 in its leftmost position 51, thereby retaining follower roller 62 adjacent the high velocity portion 60a of cam 60. Accordingly, following the rotation and tilting of print element 1 to select the character W, print element 1 is then actuated to print the W at a relatively high velocity.

FIG. 9 illustrates the impression selection and the actions of the mechanisms during the printing of a character or a No Print operation. For illustrative purposes, it is assumed that a cycle of printing takes approximately 75 milliseconds shown horizontally in FIG. 9. The relative motions of various elements involved in the printing of a character or in a No Print operation are depicted by motion curves in a vertical direction. To illustrate the actions set forth in the chart of FIG. 9, a cycle of operation wherein high velocity of print element 1 is established will be described. With the selection of the character W, all velocity stops 55, 56, and 57 are maintained in their normal positions to limit the motion of the impression cam follower 51 in order that the roller 62 will remain adjacent the high velocity portion 60a of print cam 60. In FIG. 9, a curve designated high velocity shows the relative movement of the velocity shift sleeve assembly 64 in relation to its home position. Some slight movement does occur. The action is initiated about 4 milliseconds after the beginning of the print cycle at the point designated Pull Velocity Stop. Two curves are related to the motion of the velocity stops and show the range for an Early and a Late engagement, With the retention of high velocity stop 55 in position, print cam 60 imparts a high velocity having a relatively rapid rise as indicated by the print cam curve designated High in FIG. 9. As the print cam rotates, the rotation and tilting of print element 1 is completed at about 32 milliseconds as indicated by the lines designated Tilt and Rotate. Print element 1 is retained in the position to which it is tilted by a tilt detent that maintains tilt stability from about 35 milliseconds to 47 milliseconds. The actual contact of print element 1 with ribbon 6 and document 5 occurs during the interval from about 42.5 milliseconds to 46.5 milliseconds designated Print contact. A Chopper cam sets the escapement pins 35, FIG. 1, during the interval indicated by the chopper cam curve in FIG. 9. The movement of the escapement pawl following the printing of a character is shown by the Escapement pawl curve. The escapement pawl is moved out of engagement with pinwheel 26, FIG. 1, at the point indicated at about 47.5 milliseconds in FIG. 9. An escapement interposer restore cam serves to restore the escapement action beginning about 50 milliseconds and rising to a peak about 60 milliseconds. The restoration of the velocity stops to their normal positions is shown by the line designated Restore which slants to the zero line during interval of 5070 milliseconds.

Since the selection and printing action takes place at high speed, the elasticity of the linkage involved in the print impression control allows the velocity shift sleeve assembly 64 to overshoot and undershoot the desired

portion

60a, 6017, or 60c of print cam 60. In order to dampen the undershoot indicated by the dashed lines 110 and 111 in FIG. 9, a velocity detent 112 is provided. Velocity detent 112 has spaced teeth at 113 that are arranged for engagement with an extension 32:: on the connector 82 as the slider assembly 64 is moved to the right during the impression control action. The kinetic energy of the slider assembly is absorbed through the engagement of the extension 82a with one of the teeth 1113 and the action of a detent buffer spring 114.

Near the end of each cycle, a detent cam 130 cooperates with a detent follower 131 to rotate the same in a clockwise direction and move the detent 112 sufficiently far away from extension 82:: to permit the restoration of the slider assembly 64 to its home position.

Printing of character with medium velocity It is now assumed that the character B, requiring a medium velocity actuation of print element 1 is selected. Following repression of key 11 and interposer 21 and the subsequent actuation of cycle clutch 46 and rotation of filter shaft 27, interposer 21 is moved toward the front of the apparatus (to the right in FIG. 1). A tab 21a on interposer 21 acts against a vane 96 that is fixedly attached to a rotatable bail 97. Bail 97 extends to the left to a medium velocity bail crank 98 that is mounted to the bail 9'7. Attached to one end of bail crank 98 is a medium velocity link 100 having its other extremity attached by a clevis 101 to a slotted portion 55a of velocity stop 55. As a result of the movement of interp-oser 21, link 100 is moved to the right in FIGS. 1 and and pulls the high velocity stop 55 downward out of contacting position with extension 51a of impression cam follower 51. Velocity stops 56 and 57 remain in position at this time.

The impression is now under control of velocity stop 56 which, as can be seen in FIG. 5, is cut slightly more I to the right than velocity stop 55. Accordingly, extension 51a on cam follower 51 is permitted to move further to the right in the direction of arrow '70 in FIG. 5 and through the linkages previously discussed rotates the lever 78 about pivot point 90 thereby moving pulley 79 toward the right in FIG. 1. The movement of pulley 79 is such that roller 62 is now positioned opposite the medium velocity portion 60b of print cam 60. Following the selection of the character B, which is taking place concurrently with the impression control changes, print element 1 is actuated against document 5 and due to the co-action of follower 62 and cam portion 6%, a medium velocity of print element 1 is established for the character B.

The graph in FIG. 9 shows the actions of the printing mechanism when the medium velocity stop 56 is selected. The print cam action and velocity are represented by the print cam line designated Medium. Except for the changes in velocity exerted by stop 56, the printing action is comparable to that described in connection with the selection and the printing of the character W that occurred at high velocity.

Printing of character with low velocity The comma character is now selected for printing and requires a low velocity operation of print element 1. Depression of key moves interposer 20 and operates cycle clutch 46 and filter shaft 27, as before. Interposer 20 is moved to the right (left in FIG. 7), operates against the various bails 29 to select the rotation and tilting for print element 1, and also moves into contact against a vane 105, FIG. 1, that is fixedly attached to a bail 106 for establishing low velocity of print element 1. Bail 106 is secured to a bail crank 107. Rotation of vane clockwise in FIG. 1 also rotates crank 107 clockwise and crank 107 pulls an attached low velocity link 108 to the right in FIG. 1. Link 108 is attached to the medium velocity stop 56 and pulls stop 56 out of position so that contact with follower extension 51a is prevented. Velocity stop 56 has an extension 56a, FIG. 5 that overlaps the high velocity stop 55. Therefore, movement of velocity stop 56 downwardly in FIG. 5 will effect movement of stop 55 downwardly at the same time. The action just described leaves the low velocity stop 57 in position for contact with follower extension 51a during the cycle. Follower 51 thereupon is able to move further to the right in the direction of arrow 70 in FIG. 5, pulley 79 is moved further to the right in FIG. 1, and follower roller 62 is thereupon positioned opposite the low velocity portion 60c of print cam 60. During the actuation of print element 1 following the rotate and tilt selection of the comma character print element 1 is thereafter actuated under control of cam portion 600 to establish a low velocity printing of the character The low velocity selection required for the printing of the comma character is illustrated in FIG. 9, as for the other velocity stops. The print cam motion is more gradual during a low velocity operation as indicated by the curve for the print cam designated Low. The selection of the character, the printing action, and the restoration of the mechanisms occurs in a manner comparable to that encountered during the printing of the characters iv]?! iB.,,

Cyclical N0 Print action The mechanism disclosed herein provides for a No Print action of print element 1, under certain circumstances. As described in the Cralle et al. application, the depression of spacebar 14 operates the pin wheel assembly 26 to store the value of the escapement for later use during the justification of a line and results in the movement of the carrier'3 and print element 1 to the right either 2 or 3 spacing increments. For purposes of illustration, it is assumed that the apparatus has only a single spacebar 14 that moves carrier 3 a predetermined number of escapement increments. In a typical application, means will be provided, not shown, for adjusting the actual number of spacing increments for carrier 3 under operator control with, for example, a range of 3 to 9 increments established by rotation of a dial and any of the selected increments being effected by movement of the single spacebar 14. A dial arrangement of this nature is shown in US. Patent 2,294,722, R. D. Dodge, entitled, Typewriting Machine.

As indicated in the Cralle et al. patent, the escapement mechanism utilizes certain common driving elements including the cycle clutch 46 and the filter shaft 27 and requires an interposer 33 as for any character that is selected to be printed. However, in the case of a spacing operation, no character is actually selected for printing, and it is desirable to deactivate print element 1. This is accomplished in the following manner.

In FIGS. 1 and 6, interposer 33 has an extension 33a that is adapted to contact a vane that is mounted to a No Print bail 121. When filter shaft 27 rotates, interposer 33 is moved to the right in FIG. 1. Extension 33a contacts vane 120 to rotate No Print bail 121 counterclockwise. Attached to the leftmost extremity of bail 121 is a No Print bail crank 122 having two

extensions

123 and 124. Attached to extension 124 is a link 125 that is connected at its other extremity to an extension 57b of the low velocity stop 57. Rotation of No Print bail 121 and bail crank 122 counterclockwise pulls link 125 upward and rotates velocity stop 57 sufficiently counterclockwise to move it out of contacting engagement with impression cam follower 51.

Stops

55 and 56 are also rotated counterclockwise and pulled out of the way with respect to follower 51 by

extensions

56a and 57a.

Under these circumstances, therefore, none of the velocity stops 55, 56, or 57 is in position for engagement with the impression cam follower 51. When filter shaft 27 and impression cam follower 50- rotate during the spacing cycle, follower 51 is free to move to the furthest extent permitted by a stop eccentric 127, FIGS. 1 and 5. With the movement of follower 51 to the extent indicated, pulley 79 moves to the right in FIG. 1 a distance sufficient to place roller 62 opposite the No Print cam location 60d. The No Print cam portion 60d may have no rise or negligible rise so that no driving force is imparted through the drive train to print element 1 during the cyclical operation of the mechanisms. Therefore, the print driving mechanisms associated with the interposers are effective to operate and restore the keyboard as usual and to enable the storing of the number of escapement units occurring as a result of depression of spacebar 14, but do not operate the print element 1, as is normally the case when a character to be printed is selected.

In FIG. 9, the motions involved are simply indicated by the straight line designated No Print with the understanding that no motion is imparted to the print element 1 as is normally the case during the printing of a character. The Tilt, Rotate, and Print contact, areas in FIG. 9, are also inapplicable in the present instance.

Manual control of N Print Privision is made in the present apparatus for controlling the impression mechanism to establish a No Print mode for an extended length of time. The manual control is in the form of a No Print keybutton 15, FIGS. 1 and 8. No Print keybutton has an associated keylever 135 mounted with a spacer element 136 for rotation and linear movement on a shaft 137. No Print keylever 135 has a slotted portion 135a that enables the aforementioned movements. Another slotted portion 135]) cooperates with a pin 138 extending from a spacer 137. The slotted portion 13512 has two home positions. The lower end of No Print keylever 135 is normally maintained toward the rear of the apparatus by a restoring spring 139.

The No Print key is arranged to permit a No Print operation for a single cycle, or for multiple cycles of operation, as required. Associated with the No Print keylever 135 is a transfer crank 140. Crank 140 has an eX- tension 140a arranged for engagement with the extension 123 associated with the No Print bail crank 122, previously noted. To effect a No Print mode for a single cycle, No Print keybutton 15 is depressed, thereby depressing keylever 135 and transfer crank 140 downwardly. The extension 140a of crank 140 moves upwardly, rotates the No Print bail crank 122 in a counterclockwise direction, moves all of the velocity stops 55, 56, and 57 out of contacting engagement with follower 51, and enables the movement of the roller 62 opposite the No Print cam portion d.

If no printing required during a plurality of cycles of operation of the apparatus, the No Print key 15 and keylever are moved toward the rear of the machine, pivoting keylever 135 counterclockwise about shaft 137 and enabling the engagement of pin 138 with the rear slot in the slotted portion 1351). Upon such engagement, the No Print keylever 135 is maintained in a downward position for an indefinite period of time until restored by the operator. The transfer crank 140 is also retained downwardly, and the No Print bail crank 122 is maintained in a counterclockwise rotated condition, all of the velocity stops 55, 56, and 57 are maintained out of engagement with follower 51, and no actuation of print element 1 occurs because roller 62 is positioned opposite the No Print cam 60d.

The foregoing No Print mode over a plurality of cycles is useful, as indicated before, during preliminary typing efforts in connection with the justification of printed matter on document 5.

Referring to FIG. 9, the No Print action established under manual control appears similar to the No Print action established in a cyclical manner as during the operation of the spacebar 14, previously described.

It is apparent from the preceding description that a simplified impression control mechanism has been provided with a wide range of velocity control conditions from a No Print condition to a high velocity condition, and having provision for both automatic cyclical control and manual control, as required.

Numerous modifications can be made in the apparatus. For instance, the printing apparatus may be used for Input/Output with the character selecting and functional mechanisms operated automatically by electromagnets, rather than manually as shown. As another example, a single velocity for characters, with a No Print mode for functions, may be provided, rather than high, medium, and low velocities. Also, the apparatus may be normally maintained in a No Print mode and all velocities selected when characters are to be printed rather than normally maintained in a high velocity mode.

While the invention has particularly shown and described with reference to a preferred embodiment thereof, it will be understood by those skilled in the art that various changes in form and detail may be made Without departing from the spirit and scope of the invention.

What is claimed is:

1. Printing apparatus, comprising:

selection means for selecting characters for printing and functional operations to be performed;

printing means operable to print characters selected by said selection means;

means for effecting functional operations normally not requiring actuation of said printing means, such as spacing;

print impression control means for establishing a plurality of predetermined velocities for said printing means according to the characters selected and a No Print condition of said printing means, said impression control means including a control cam, associated linkages, a plurality of print cam means related to the velocity required for any character selected and a No Print cam with rise in the range of none to negligible, a. cam follower, and further including a fixed stop associated with said No Print cam, and a group of movable settable velocity stops associated with said control cam and selectively positionable to a first state with at least one stop positioned for establishing a driving connection from said control cam to move said follower adjacent the print cam means that imparts the velocity required for any character selected, and positionable as a group to a second state wherein all movable stops are moved out of driving relation to said control cam, but a N0 Print connection is established under control of said fixed stop to move said follower adjacent said No Print cam;

common drive means for driving said selection means, said printing means, said print impression control means, and said functional means, on a selective basis;

a plurality of actuatable character by mechanisms for initiating character selection, and functional key mechanisms for initiating functional operations, both of said types of key mechanisms also initiating operation of said common drive means, as required;

and means for selectively and positively positioning said velocity stops to said first state during character printing cycles and for positively positioning said velocity stops to said second state during functional cycles.

2. The apparatus of claim 1, wherein:

said printing means comprises a single element print head movable from a rest position to a printing position against a document to be printed.

3. The apparatus of claim It, wherein:

said print impression control means establishes three velocities of said print element, designated respectively, high, medium, and low, in addition to said No Print condition.

4. Printing apparatus, comprising:

printing means operable to print characters selected by said selection means;

impression control means for establishing a plurality of predetermined velocities for said printing means according to the characters selected, said impression control means including a cam, associated linkages, a cam follower, and a plurality of print cam .rneans related to the velocity required for any character selected, said print cam means including a No Print portion with rise in the range of none to negligible;

a plurality of actuatable character key mechanisms for initiating character selection and functional key mechanisms for initiating functional selection, both of said types of key mechanisms also initiating operation of said common drive means, as required;

connecting means for rendering said impression control means effective to control the velocity of said print element during character printing cycles, and for deactivating said impression control means to thereby establish a -No Print condition of said printing means during functional operations of said apparatus;

means associated with said character key mechanisms including selectively settable velocity stops positioned in proximity to said cam follower for controlling the same during character printing cycles, said velocity stops having projections of varying rise to control the extent of movement of said cam follower, each velocity stop being supplied with successively less rise from highest to lowest velocity, and wherein said means associated with said character key mechanisms is effective to maintain the highest rise stop in position when a high velocity is required, to move all stops out of the way except a required lower velocity stop as successive lower velocities are required during character selection to thereby establish a driving condition to position said cam follower adjacent the print cam that imparts the velocity required for the character selected;

and means associated with said functional key mechaanisms effective to move all of said velocity stops out of contacting engagement with said cam follower to thereby establish a connection to position said cam follower adjacent the No Print portion of said print cam means when a No Print condition is to be established.

5. Printing apparatus, comprising:

printing means operable to print characters selected by said selection means;

means for effecting functional operations normally not requiring actuation of said printing means, such as spacing,

impression control means for establishing a plurality of predetermined velocities for said printing means according to the characters selected, said impression control means including a cam, associated linkages, a cam follower, and a plurality of print cam means related to the velocity required for any character selected;

a plurality of actuatable character key mechanisms for initiating character selection, and functional key mechanisms for initiating functional selection, both of said types of key mechanisms also initiating operation of said common drive means, as required;

connecting means for rendering said impression control means effective to control the velocity of said print element during character printing cycles, and for deactivating said impression control means to thereby establish a No Print condition of said printing means during functional operations of said apparatus;

means associated with said character key mechanisms including selectively settable velocity stops positioned in proximity to said cam follower for controlling the same during character printing cycles to thereby establish a driving connection to position said follower adjacent the print cam that imparts the velocity required for the character selected;

and manually operable No Print means that is selectively settable to deactivate said print impression control means in a selective manner and irrespective of the functional or character printing operations required.

6. The apparatus of claim 5, wherein:

said No Print :means is operable to two conditions, the first condition establishing a temporary No Print mode and the second condition establishing a N0 Print mode for an extended period of time, until said No Print means is released.

7. Printing apparatus, comprising:

printing means operable to print characters selected by said selection means;

impression control means for establishing a plurality of predetermined velocities for said printing means according to the characters selected and including a No Print position, said impression control means including a cam, associated linkages, a cam follower, and a plurality of print ca m means related to the velocity required for any character selected;

connecting means for rendering said impression control means effective to control the velocity of said print element during character printing cycles, and for deactivating said impression control means to thereby render said printing means inactive during functional operations of said apparatus;

means associated with said character key mechanisms including selectively settable velocity stops positioned in proximity to said cam follower for controlling the same during character printing cycles to establish a driving connection to position said cam follower adjacent the print cam that imparts the velocity required for the character selected;

and means effective during operation of said impression control means to control overshooting or undershooting of said impression control means.

8. The apparatus of claim 7, wherein:

said undershoot and overshoot control means comprises a detent associated with the impression control means, said detent being effective in each cycle to dampen the movement of the impression control means following the selection of impression velocity required and prior to actuation of said printing means.

9. The apparatus of claim 8, further comprising:

cam control means for restoring said detent means following a printing operation during each printing cycle of operation.

10. Printing apparatus, comprising:

printing means operable to print characters selected by said selection means;

impression control means for establishing a plurality of predetermined velocities for said printing means according to the characters selected, said impression control means including a cam, associated linkages, a cam follower and a plurality of print cam means related to the velocity required for any character selected;

a plurality of actuatable character key mechanism for initiating character selection, and functional key mechanisms for initiating functional selection, both of said types of key mechanisms also initiating operation of said common drive means, as required;

connecting means for rendering said impression control means effective to control the velocity of said print element during character printing cycles, and for deactivating said impression control means to establish a No Print condition of said printing means during functional operations of said apparatus;

means associated with said character key mechanisms including selectively settable velocity stops positioned in proximity to said cam follower for controlling the same during character printing cycles to establish a driving connection to thereby position said cam follower adjacent the print cam that imparts the velocity required for the character selected;

a selectively settable escapement memory means for storing the escapement history of individual lines as printing and functions progress; and

means operable under control of said character key mechanisms, said functional key mechanisms and said common drive means for setting said escapement memory means as required, during printing and No Printing modes of operation.

11. The apparatus of claim 10, further comprising:

proportional escapement means for relatively moving said printing means and a document to be printed, proportional increments that are dependent upon the character selected for printing or the functional operation performed; and wherein,

said memory means stores said proportional increments.

12. The apparatus of claim 11, wherein:

said memory means comprises a pin wheel memory having pins settable to a state representative of escapement increments as printing and functional operations occur.

References Cited UNITED STATES PATENTS 2,699,857 1/ 1955 Wales 197-1 2,879,876 3/1959 Palmer et a1 l9716 3,239,049 3/1966 Voit 197-17 X ROBERT E. PULFREY, Primary Examiner.

E. S. B-URR, Examiner.