US2186341A - Impression roller control - Google Patents

Description

F.- NIGRA IMPRESSION ROLLER CONTROL Filed May 9, 1958 l INVENTOR.

FERDINANO Mmmv Patented Jan. 9, v194() UNITED STATES-- OFFICE 2,186,341.V IMPRESSION ROLLER contraer." Ferdinand Nigra, San Francisco, Calif.,.aslsignor to Niagara Duplicator .00.,

Application May 9,1938, serial No; 206,763v

' iclaims 4(ci. 1p1-11s)L The inventionrelates to certain controlsfor an im-pression roller which is arranged to engage asheet to be printed against a printing cylinder or drum.

An object of the invention is to so mounten impression roller which is freed of external bearing contact between its periods of' engagement with successive sheets being printed in a continuously operating duplicator or the like as to permit i an axial displacement of the roller whichmaybe be urged upon it during its functioning.

Another object is to. provide a means for automatically Causing a working-speed rotation of the 15.. impression roller while it is displaced from its drag as the roller is 'first brought into engagement with a sheet to be printed on.

A further object is to provide for an automatic return of ,thel roller to its undisplaced position as it is moved between positions in which it engages a sheet and is engaged by the driving means.

The invention possesses other objects and-fea tures of advantage, some of which, with the foregoing, will be set forth or be apparent, in the following description of ar typical embodiment thereof, and in the-accompanying drawing. in which,

Figure 1 is a fragmentary side elevation of a' rotary duplicator mechanism havingV the impres-v sion roller thereof mounted and controlled'in accordance with the present invention andinoperatively disposed with respect to the'printing cylinder of the duplicator. y l

Figure 2 is a sectional view'taken generally in aV planethrough the line 2-2 inFigure 1. I

Figure 3 is a fragmentary sectional elevation taken `in part in atransverse plane through the cylinder andfin part on the line 3-3in Figure 2.

The features of the present invention areI incorporated in the fragmentarily shown mechanism vof a duplicating machine in which a stencilA 2 is carried on a rotary cylinder for its'printing engagement with a sheet of paper or other material for receiving printing. `The printing cylinder 3 is suitably supported forrotation about an horizontal axis, is restrainedagainst axial shifting, and may be actuated'v hand or byasuitable motor.

By reference to the drawing, it

sheet on a feed table ,I5 to dispose its advance' end portion between pairs of rupper and lower '5 5 feed rollers I'B and I1, isthereaftereng'aged byl operative position and so eliminate any. inertia der.

win be noted' that a sheet I4 of print-receiving'material which has been advanced from the top` of a stack of andy-between said rollersandis therebyadvanced f urth'erforthe' disposal of its front end portion vbetween the stencil 2 on the rotary cylinder '3 andfanimpression roller I8,jand is nallygripped between the cylinder and roller to continue the 'feeding movement of thev sheet .while the latter is being progressively printed. As shown, the impression roller I8 is supported for its free rotation f on a shaftI 9.which is carried by and between corresponding and rearward ends of lever-like members 20 which are intermediately pivoted on a rockeshaft v2I which is journalled in and between sidefraxne members 5, said. shaft being disposed forwardly of a vertical plane through the cylinder axis.

The ,forwa'rd ends ofk the lever members 20 are connected by a .bar 22, and a tension spring 23 extends generally rearwardly from the bar 22 to constantly urgea' resilient engagement of the impression roller I8 against the 'cylinder 3. The ex" tr'emities of the shaft I '9 and the bar 22 pivotally" engage the ends .of the levers 20 whereby the generally planar assembly of these members` may be distorted transversely thereof if such is required to insure an even bearing of the impression roller withiand' along'the cylinder.

Arms 24' extend rigidly and radially from the shaft 2l for simultaneous engagement with the bar 22 as a meansv toV rock theV levers 2Ilto` dispose the roller I8 out" ofy engagement with vthe vcylin- An arm '25 extends rigidly from the shaft 2I in angular'relationto the arm 24 thereat, and a tension spring`26 is operative againstthe free end of the arm 25 whereby the arm` 25 is resill iently urged to maintain an engagement thereof with an adjustable stop 2l;` it will be understood that the stopV 2l maydetermineone limitv of oscillation of the shaft 2|. The rocking of the shaft 2| to displace" the roller I8 at theappropriate time in the feeding cycle of a sheet I4 may be effected in anyv suitable manner; mechanism for providing the complete cycle by and in synchronism with therotation of the cylinder is shown and'described in detail in myUnitedY States Patent No. 2,106,930 0f Feb. 1', 1938.

long enough to permit a longitudinal shifting of the shaft to disengage its other end from the other arm 20; in this manner, the roller I8 may bereadily removed or replaced.

The roller I8 comprises a core tube 4I carrying a relatively thick and resilient tread 42 for engaging beneath a sheet I4 at the stencil on the cylinder. Suitable anti-friction bearing assemblies are provided in the core tube 4I at opposite ends thereof, said bearings having their outer ball races 44 slidably fitting enlarged terminal portions of the tube bore and their tubular inner ball races 45 slidably receiving the intermediate shaft portion. The present arrangement forenclosing the bearings within the tube 4I is understood to minimize the probability of ink and/or dust getting therein.

An helical spring 41 encircles the shaft adjacent its end portion 31 and inwardly of the arm 20 thereat and is compressedly engaged between the adjacent inner race 45 and a pin or key 48 extending through the shaft. The spring 41 is constantly operative to urge the roller I8 along the shaft toward a collar or stop 49 fixed on the shaft, the bearing structures being such that the races thereof are restrained against relative axial movement. The normal action of the spring 41 against one race 45 results in an engagement of the shoulders 58 atA the inner ends of the counterbores which receive the races 44 with the latter races to effect the engagement of the other race 45 with the shaft collar 49. It will be obvious that 'the springs 40 and 41 are constantly coactive to yieldingly urge a retention of thev roller I8 in a longitudinally centered position with respect to the levers 20 which support the shaft I9 whereby the roller I8 may be self-centering when it is free of lateral contacts. The present self-centering mounting for the roller I8- requires a minimum number of parts, and may be readily assembled or disassembled because the bearing races need not be fixed to other members.

It will now be noted that the feeding speed of a sheet I4 is preferably arranged to be the same as the4 longitudinal speed of .the stencil on the periphery of the cylinder 3 whereby the sheet and stencil may move together at the same speed when the impression roller I8 presses the sheet against the cylinder for printing. The peripheral speed of the operative roller I8 is, of course, the same `as that of the paper sheet and the Stencil during printing, the rotationof the roller then being solely controlled by the movement of' the sheet portion engaging it. When the printing of each sheet is completed and the roller is moved away from the cylinder, the freed-roller will tend to rotate at a decreased speed whereby its rotative speed must be raised to its operative value at its subsequent application to the succeeding sheet. Since any slowing down of the rotation of the roller between its operative applications produces an undesirable reactive drag upon vthe sheet as the roller rst engages the leading sheet portionmeans are provided to insure a constant spinning of the impression roller when it is inoperatively disposed whereby its peripheral speed at contact may be substantially or exactly equal to the speed of the advancing sheet, said means comprising a roller spinning device which is hereinafter described. i i.

At one end thereof, the co-re tube 4I of the roller It extends somewhat beyond the tread 42 of the roller, and the exposed tube portion is nuted or otherwise roughened to provide afriction roller 53. The side framemember 5 of the duplicator structure nearest the roller 53 rotatably mounts a pair of mutually engaged friction rollers 54 and 55, the roller 54 having a resilient tread 56 and being so positioned that the friction roller 53 on the impression roller I8 is arranged to engage it only when the impression roller lis disposed in its limiting position away from the cylinder 3, at which time the rollers 53 and 54 and 55 respectively comprise driven and idler and drive rollers for the impression roller.

Means are provided for operating the roller 55 at such a rotative speed that the rotative speed of the impression roller I8 may, through the coaction of the idler roller 54 with the friction roller 53, be maintained at its operative value at all times. As 'particularly shown, the drive roller 55 is provided as part of a rotary member 56 which also provides a belt pulley 51 with which a drive belt 30 is constantly engaged, said belt also driving the cylinder 3 in the present instance whereby the impression roller and the cylinder may be driven synchronously from the belt 30 at any operative speed for the cylinder. The present device of maintaining the operative speed of the impression roller constant permits a much faster printing rate with the duplicator than when the device is not provided, thus eliminating an unfavorable factor which has heretofore limited the operative rate of duplicators generally. The movement of the impression roller between its limiting positions where it is driven by the sheet on the cylinder and by the belt 3l] is relatively rapid and more or less a snap action, whereby `little speed is lost as the roller moves from one position to the other. y

Recalling that in sheet-handling devices wherein a sheet of material is gripped and advanced between coacting rollers, a very slight variation from a true cylinder of uniform crosssection of one or both rollers, or a lack of true parallelism of the roller axes, or a variation in sheet thickness, and other factors, may operate to urge a lateral motion of a sheet gripped thereat whereby the sheet may be wrinkled or even torn, it will be understood that the self-centering mounting of the roller I8 on and between the levers 20 permits any required shift of the roller to avoid unfavorable eifectson the sheet, and that the roller is automatically recentered While it is free of the cylinder and the idler roller 54. It will also be understood that the engagement ofthe rollers 53 and 54 might also tend to effect a relative axial shifting of these rollers, this resulting in a frictional drag if the self-centering device were lacking. It will thus be understood that` the permitted axial shift of the impression roller while it is engaged b-y the cylinder orth-e roller 54, and the self-centering of the roller while it is free is of marked value in connection with impression rollers which operate intermittently.

From the foregoing description taken in co-nnection with the accompanying drawing, the advantages of the construction and use of the device will be readily understood by those skilled in the art to which the invention appertains. While I have described the features and the principle of operation of a structure which I now consider to be a preferred embodiment of my invention, I desire to have it understood that the disclosure is primarily illustrative, and that such changes may be made, when desired, as fall within the scope of the following claims.

means automatically operative to"` maintain theA rotary speed of the ,roller atits operative value while the roller is inoperatively disposed with respect to the cylinder.

2. In a rotary duplicatoror the like, a driven printing cylinder, an impression roller for coaction with said cylinder to pressa sheet of printreceiving material against the cylinder and'to be rotated solely by reason of its contactwith the sheet, means mounting said roller for lateral movements thereof to and Vfrom an operative relation of the roller to the cylinder, means for automatically effecting both said movements of the roller during each loperative cycle of the cylinder, means actuatable to rotate the roller at a fixed speed While itis inoperatively disposed With respect to the sheet, and a common drive means for the cylinder and roller rotating means 'such that the rotative speed ration of the cylinder and roller may be maintained at a ,conf f stant value While the roller is inoperatively ldisposed Withvrespect to the cylinder.

' 3. In a rotary duplicator or the like,l a driven printing cylinder, an impression roller arranged for its "operative coaction Awith said cylinder to press av sheet of print-receiving paper or the like against the cylinder and to be rotated solely `loy reasonof its contact with the sheet, means supporting said 4roller for lateral movements thereof between limiting positions in which it is respectively operative and inoperative with respect to the cylinder, and means coactive .With

' the roller solely While it is disposed in its inoperative position for maintaining its operative rotary speed.

4. In a yprinting apparatus, a driven printing cylinder mounted against an axial shifting thereby reason of its contacty with the sheet, means supporting said roller for lateral movements thereof to and from 'its operative position and for its independent longitudinal shifting from a normal intermediate position thereof, means coactive with the roller to maintain its operative rotary speed `solely While it.' is disposed in a limiting inoperative position, andmeans constantly operative for yieldingly urging a retention of the roller in its said normal intermediate position thereof. y h -FERDINAND NIGRA.

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