US2263323A - Printing press - Google Patents

Description

Nov. 13, 1941. A. M..w1Kw.E. R 6 3 PRINTING PRESS 4 Sheets-Sheet 1 FiledJune 13, 1940 v I INVENTOR. ARTHUR M. WICKWIRE, JR-

BY: A

ATTORNEY.

NOV. 18, 1941. ACM, WICKWIRE, JR 2,263,323

' PRINTING PRESS.

Filed June 13, 1940 4 Sheets-Sheet 4 INVENTCR ARTHUR M. WICKWIRE, JR.

f BY

ATTORNEY Patented Nov. 18, 1941 PRINTING PRE S S Arthur M. Wickwire, Jr., Mountain Lakes, N. .L, assignor to Champlain Corporation, Garfield, N. J., a corporation of New York Application June 13, 1940,Serial No. 340,241

Claims.

This invention relates to rotary printing presses, or the like, in which an impression cylinder cooperates with a printing or other operating cylinder. The invention aims to improve the method of adjusting and controlling'the relative position of the operating and impression cylinders, and the application or withdrawal of pressure therebetween and to provide an eilicient machine for carrying out the method. The invention is particularly applicable to high speed intaglio or gravure printing wherein a plurality of different colors are to be printed on a continuous web of paper, textile, or other sheet material, and where the printing is of such a nature as to require special attention to the control of pressure between the impression and printing cylinders.

In prior machines, wherein a central source of fluid pressure has been employed to control the pressure of the impression cylinder against the printing cylinder, and to equalize the pressure at the two ends of the cylinders, it has been found that objectionable differences sometimes take place in the speed with which the fluid pressure feeds the two ends of the impression cylinder toward or away from the printing cylinder, thereby causing the impression cylinder to depart from close parallel relationship with the printing cylinder, and thus tending to tilt the journals of the impression cylinder relatively to their bearmgs. impression cylinder to tilt or skew from its normal position, the journals and bearings of the impression cylinder. and other parts of the machine are undesirably strained and tend to jam and wear objectionably.

In addition to this difiiculty, I have found that,

a in a multi-unit press in which the impression cylinder position is controlled by fluid pressure, there is a tendency for the impression cylinders in the different units to move at different speeds while being fed toward or away from the printing cylinders, thereby displacing the web from the normal critical position required for perfect registration. Moreover, when printing a very thin sheet of material, such as regenerated cellulose, because of the extra sensitivity of such a sheet to slight variations in the printing pressure between the impression and printing cylinders, such usual pressure variations tend either to underprint the sheet or to force the sheet into the cells of the engraving and undesirably emboss the sheet or otherwise mar it. Trouble may also be encountered'when operating an intaglio press at high speed because of the tendency for the As a consequence of this tendency of the' impression cylinder to vibrate or chatter objectionably, thereby periodically varying the amount of pressure between the impression and printing cylinders, so as to mar the printing and detract from the uniformity and other desirable qualities of the printing. Furthermore, when printing relatively heavy paper at the highest permissible speeds, the amount of pressure required between the impression and printing cylinders is so high that the rubber or other resilient material at the surface of the impression cylinder becomes overheated and may sometimes be torn away. The high fluid pressure may then instantly drive the hard reinforcing core of the impression cylinder directly into contact with an engraving or other pattern on the printing cylinder, and seriously injure or destroy it.

The present invention provides an effective control system of relatively simple construction, including separate pressure applying devices having cooperating means for simultaneously controlling and equalizing the movement of the two ends of the impression cylinder in each unit of a multi-unit machine, to maintain each impression cylinder closely parallel with its corresponding printing cylinder during the time the impression cylinder exerts pressure on the printing cylinder, and during the periods when the impression cylinder is being withdrawn from or reapplied to the printing cylinder. At the same time, the invention makes it possible to establish a more positive control of the amount and distribution of pressure between the impression and printing cylinders, to avoid or minimize vibration of the impression cylinder, to protect the printing cylinder from injury, to increase the printing speed, to improve the quality of printing, and generally to improve the construction and operation of a printing machine or the like, while avoiding or minimizing the difliculties referred to above, and while providing the advantages of centralized control of the position of the impression cylinder relatively to the printing cylinder and of the pressure therebetween, for either high or low speed printing.

These and other features and objects of the invention will be understood more clearly upon consideration of the following detailed description of a now preferredembodiment thereof, and the accompanying drawings, in which:

Fig. 1 is a. side elevational view of a. portion of a multi-color printing press, showing two of the printing units with drive shafts, inking mechanism, etc.- omitted;

Fig. 2 is a fragmentary plan view taken substantially along the line 22 of Fig. 1, showing a portion of one of the printing units and associated drive shafts;

Fig. 3 is a longitudinal vertical sectional view taken substantially along the line 3-3 of Fig. 2;

Fig. 4 is a transverse vertical sectional view taken substantially along the line 4-4 of Fig. 2;

Fig. 5 is a plan view, similar to Fig. 2, showing printing and impression cylinders similar to those of Fig. 2, but omitting the back-up cylinder;

Fig. 6 is a longitudinal vertical sectional view taken substantially along the line 6-6 of Fig. 5;

Fig. 7 is a schematic diagram showing the control system for a multi-unit press such as that of Fig. 1; and

Fig. 8 is an elevational view, similar to Fig. 6, showing further details of the stop limit switch.

I have shown my invention, as applied to a multi-color intaglio printing press of the general type disclosed in my co-pending application, Serial-No. 217,139, filed July 2, 1938, of which this application is a continuation in part, and to which reference is made for various details of construction not specifically mentioned herein. It will be understood, however, that in its broader aspects, the, invention is not restricted in its use to such a press, but may be used in printing presses generally.

Referring to Fig. 1, the multi-color printing press consists of a plurality of intaglio printing units in tandem through which the web of paper, textile, or other sheet material to be printed, is fed. Since the different units are substantially identical in their basic features of construction, except as will be noted hereinafter, only the first two units 20 and 2| of the press, are shown in Fig. 1, and it will be understood that the successive units, following to the right of units 20 and 2|, are of similar construction, each unit being adapted to apply a different color, pattern, or treatment to the web 22, as the web passes between the printing couples in each unit, 20, 2|, etc.

Each printing couple consists of a printing cylinder or roller 23, and a cooperating impression cylinder or roller 24. The printing cylinder 23 has an engraved or intaglio metal printing surface for receiving the ink from a suitable inking mechanism (not shown) such, for example, as that described in my copending application referred to above. The impression cylinder 24 has an outer annular portion or rim 25, of resilient materiaL such as rubber, gelatin, or other suitable composition for yieldably pressing the web 22 against the printing cylinder 23, while the web is fed between these cylinders. In Figs. 1 to 4, a back-up or pressure cylinder 28 is provided adjacent each of the impression cylinders 24.

As indicated in Fig. 1, the web 22 is fed into the left end of the machine, in the direction indicated by the arrowheads, and passes around feed or guide rollers 26', then between the printing couple cylinders 23, 24 of unit 20, then around web drying and guide rollers 21, between cylinders 23, 24 of unit 2|, and so on through the successive printing units. All the cylinders or rollers 23, 24, 28, 21, 28, and the corresponding cylinders of the'other units have their shafts supported by, and directly or indirectly journalled at one end in a rigid frame member 29, extending along one side of the machine throughout its length. The other ends of said cylinders are supported by and joumalled in a similar side frame 29, Figs. 2 and 4, at the other side of the machine from that shown in Fig. 1. In each printing unit the printing cylinder 23 has its shaft 38 journalled in bearings in the side frames 29. The shaft 3| of the impression cyl-, inder 24 is journalled in bearing blocks 32 (Figs. 2, 3 and 4). Each block 32 is mounted to slide horizontally between upper and lower guideways or gibs 33 secured to or formed integral with a main slide block 34 which is mounted to slide horizontally between upper and lower guideways or gibs 35 attached to the inner faces of the side frame 29.

Displacement of bearing blocks 32 in a direction axially of the shaft 3| is prevented by pilot screws 38, each of which is threaded through one of the upper guideways 33, and has its lower end fitting loosely into a pilot slot or groove 31, extending in the feed direction in the top side of the block 32. Screws 38 thus pilot the blocks 32 in the feed direction, and prevent feeding the blocks beyond the points where the ends of the slots 31 strike the screws 38. Removal of the screws 36 releases blocks 32 from the above-described restraint, and permits easy removal and replacement of the impression cylinder 24. The back-up cylinder 28, which is of rigid metallic construction and of larger diameter than the impression cylinder 24 in order to provide greater strength, has its shaft 38 journalled in the main slide blocks 34, and serves as a brace providing support for the impressioncylinder 24, which is of smaller diameter than the printing cylinder. Because of its comparatively small diameter, the middle portion of the impression cylinder 24 would tend to deflect objectionably away from the printing line when the impression cylinder presses strongly on the printing cylinder, were it not for the support derived from the back-up cylinder 28.

While the path in which the axes of the impression cylinder 24 and the back-up cylinder 28 are fed toward or from the printing cylinder 23, is shown slightly above and out of line with the axis of the printing cylinder, it will be understood that this path may be made to have any suitable angle, including zero degrees, with respect to the plane common to the axes of the printing couple 23, 24.

The impression cylinder 24 and the back-up cylinder 28 are fed readily toward or away from the printing cylinder 23, or are made to supply a desired operating pressure against the printing cylinder by two fluid pressure responsive devices, Fig. 2, each including a piston rod 39 and a piston operating chamber 40. Each piston rod 39 is adapted to be fed substantially horizontally, and is operatively connected or coupled at its free end with one of the slide blocks 34 carrying one end of the impression cylinder 24 and one end of the back-up cylinder 28. Fluid pressure applied through suitable pipes 4| urges the piston rods 39, together with cylinders 24, 28, toward the printing cylinder 23, and pressure applied through pipes 42 reverses the force and urge: the piston rod and cylinders 24, 28 away from the printing cylinder 23. In each printing unit as best shown in Fig. 7, the two corresponding pipes 4| for the two respective chambers 48 may be connected together with a leader pipe 43, and the two pipes 42 are connected together with a leader pipe 44.

Since the static pressure exerted by each piston 39 is substantially the same, the resultim pressure of each end of the impression cylinde1 should be automatically equalized. I have found, however, that the pistons in any given printing unit sometimes have an undesirable tendency to move at diiferent speeds, while feeding the impression cylinder toward or away from the printing cylinder. This may be due to the different rate of fluid flow in the branch pipes 4|, 42, connecting with the main leader, or may be due to some other cause. As a result of the different speeds of movement of the two slide blocks 34, the back-up cylinder 28, and the im-' pressioncylinder 24 tend to tilt or skew out of their desired parallel relation with the printing cylinder 23, thereby tending to cause undesirable straining or jamming of the shafts 3| and 38,

bearing blocks 32 and 34, the guideways 33 and 35, and other parts of the machine, besides greatly increasing the frictional load on the fluid control system. Moreover, even though the fluid responsive devices in each of the printing units are simultaneously controlled from a centralized source, the irregular frictional conditions resulting from such strain and jamming sometimes cause the impression cylinder in one printing unit to move out of unison with that in another unit. This tends to disturb the balance of tension in the web between the units and to displace the web from one unit to another, thus upsetting or preventing perfect registration of impressions on the web.

In order to counteract these difficulties, I have provided, on the lower side of each bearing block 34, a toothed rack 45 which engages a pinion 46 mounted on a shaft 41 journalled in the side frames 29. Since the two racks 45 are meshed with the two pinions 46, which are rigidly con: nected together by the shaft 41, and the slide blocks 34 are assembled in alignment with each other, this alignment will be maintained for all positions of the blocks 34 and said blocks 34 will move in unison and at the same speed, thereby maintaining the impression cylinder 24 and the back-up cylinder 28 closely parallel with the printing cylinder 23 during movement of said impression cylinder. The rack and pinion mechanism 45, 46, 41 has been found not only to maintain the desired closeness of parallelism of the cylinders 23, 24, 28, but also provides a sufficiently loose coupling between the slide blocks 34 at the opposite ends of the cylinders, to permit the fluid feed mechanism to equalize, to the desired degree, the pressure between each end of the impression cylinder 24 and the printing cylinder 23. -It .will be noted that the rack and pinion mechanism 45, 46, 41 is responsive to and is wholly under the control of the fluid pressure in pipes 4| and 42, so that no extra attention or manipulation is required for its operation.

In order to reduce any tendency for the fluid to flow faster to or from either cylinder 40 in the same printing unit, there may be provided in each branch pipe 4|, Fig. 2, a throttle nipple 52, shown in an enlarged broken away view in one branch pipe 4|. The nipple 52 has an orifice 53, adjusted to such a size as to make the fluid flow therethrough approach as nearly as possible to equality with that through the corresponding throttle nipple 52 in the other branch 4| of the same unit. The strain and. frictional load on the rack and pinion mechanism is thus effectively minimized.

While the rack and pinion mechanism equalizes the speed at which each end of the impression cylinder is fed in any given printing unit,

this expedient does not insure equality of the speed in the different printing units. To obtain such equality in the different units, the throttling eifect of the nipples 52.in the different units may be adjusted to, equalize the flow of fluid to each of the chambers 40, thereby causing the pistons 39 and cylinders 24, 28 to move more nearly in unison and aiding in preserving the desired registration between the printing cylinders 23 and the web 22, It will be seen that, as regards the function of equalizing the speed of adjustment of the impression cylinder in the different units, the two nipples 52 in any one unit are equivalent to a single nipple (not shown) in the pipe 43 (Fig. 7) for that unit.

For cooperation with each fluid pressure responsive device 39, 40, slide block 34, and each of the cylinders 23, 24, 28 in a given printing unit, I have provided and shown in Fig. 8 a limiting mechanism 54, which serves as a vibration damping element, pressure limiter, and printing cylinder protector. This limiting mechanism 54 includes a stop rod 55 which is secured at one end to slide block 34 and has a screw threaded free end extending freely through an opening or slot 56 in a stop lug 51, fast to the frame 29. A stop nut 58, screwed on the free end of rod 55, may be adjusted to any desired position relative to lug 51, and a check nut 59 serves to lock the nut 58 in any desired adjusted position. The essential elements of this limiting mechanism are also shown in Fig. 7.

In adjusting the limiting mechanism 54, the nut 58 is given such a position as to fix a limit on the pressure exerted by the impression cylinder 24 on the printing cylinder 23 for printing a web of very thin material, such as regenerated cellulose, for example. When printing such a thin material it has been found important to limit the pressure to a very light value, since appreciable increase of pressure above this value tends to emboss or otherwise mar the very thin web and squeeze out the ink. Only a slight amount of pressure is needed above that to be exerted by the impression cylinder on the printing cylinder, to insure that the proper amount of pressure is provided between these cylinders and that any slight vibrations which might tend to occur in the impression cylinder will be suitably damped out. Thus, it will be seen that the limiting mechanism 54 fixes the amount of pressure exerted by the impression cylinder on the printing cylinder, by limiting the travel or feed of the impression cylinder toward the printing cylinder. Such action limits the pressure on and deformation of the elastic outside surface of the impression cylinder as said cylinder presses the web 22 against the printing cylinder 23. Any pressure exerted by the piston rod 39 on block 34, in excess of that represented by the elastic deformation of the impression cylinder, is taken up by the lug 51, and the excess pressure serves to maintain the impression cylinder in a positive position opposing the building up of vibrations. When vibrations occur in the impression cylinder, tending to make it vibrate back and forth toward and away from the printing cylinder, the lug 51 completely blocks'and thus damps out that half of the vibration tending to move the impression cylinder from its neutral position toward the prinnting cylinder; and the cooperative action of the entire limiting mechanism 54 and the fluid responsive device 39, 40, serves to damp out the remainder of the vibration on the other side of the neutral position. By regulation of the fluid pressure the amount of damping obtained by the increment of piston pressure in excess of that utilized for pressing the impression cylinder against the printing cylinder may be adjusted to any desired value to suit the circumstances.

When the web 22 is of thick, or heavy absorptive material, or material of uneven thickness, a much greater pressure should preferably be provided between the impression and printing cylinders. Such greater pressure makes a better printing impression and prevents vibration of the impression cylinder, it being no longer necessary to use the limiting mechanism 54 for regulating the pressure of the impression cylinder on the printing cylinder or to damp out vibrations. It becomes important, however, to safeguard the printing cylinder from the possibility of being struck and destroyed or injured by the hard core of the impression cylinder in case the softer outer portion thereof should be torn away by the strain of high speed printing with high pressure. For the purpose of protecting the printing cylinder from injury of this kind, the nut 58 is given a position slightly backed off from the lug 51, so that the full pressure of the piston 39 is applied by the impression cylinder to the printing cylinder, without being limited by lug 51. However, the nut 58 may be so positioned as to engage and be stopped by lug 51 in the event of any injury to the impression cylinder which might cause it to move ObjGC'. tionably close to the printing cylinder. The limiting mechanism 54 thus serves as an adjustable protector to safeguard the printing cylinder from injury while printing at high pressure and high speed.

Figs. 5 and 6 show a modification of the impression cylinder arrangement of Figs. 2, 3, and 4, in which the back-up cylinder 28 is omitted and an impression cylinder 5| of larger diameter than the printing cylinder 23 is provided. In order to provide adequate strength for the impression cylinder 9|, a drum 62 of relatively thick metal, such as steel, is provided to back-up the rim 83 of rubber or other suitable resilient material. At each end of the drum 62 are provided roller bearings 54 which revolve around the shaft 3|. The ends of shaft 3| are journalled directly in slide blocks 65. Each block 65 has a removable bearing yoke 66 bolted thereto so as to permit easy removal and replacement of the impression cylinder. An end plate 61, screwed or otherwise made fast to each block 65, serves as an end barrier to limit axial displacement of the shaft 3|. As in the case of the arrangement in Figs. 2, 3, and 4, the rack and pinion 45, 46 are provided to maintain alignment of the blocks 65 and parallelism between cylinders GI and 23. It will be understood that the damper arrangement 54, of Figs. 2, 3, 4, though omitted from the showing of Figs. 5, 6, for purposes of simplicity, may be used in connection therewith.

When withdrawing the impression cylinder 6| from the printing cylinder 23 in response to the fluid pressure control mechanism 39, 40, it has been found convenient to provide in one of the printing units, a stop limit switch 68. Such a stop limit switch may be attached to the frame 29 and positioned so that its operating plunger 69 is aligned with the path of travel of a pin 10, slidable longitudinally in the free end of a hinged arm II which is pivoted to a base member 12 secured to the slide block 65. In the Fig. 8 construction, a helical spring 13 surrounds pin Ill and is compressed between a collar 14 locked by a set screw 15 to pin 10, and a collar 16 locked by screw TI to pin I0; while in Fig. 6 the pin 10 is merely held in the arm 1| by a suitable set screw. By adjustment of collars 14 and IS, the pin 10 may be adjusted closer to or further from switch plunger 69, so that the switch may be made to operate automatically at any predetermined point in the path of travel of slide block 34 in withdrawing from the printing cylinder. The spring 13 prevents excess pressure of pin 10 on switch 68 after the pin engages the switch. If desired, stop limit switch 68 may be rendered inoperative by swinging the hinged arm 1| to one side of its position of alignment with switcl 98. It will be understood that the switch 68 and the operating mechanism 10, ll, etc., is preferably employed also with the form of apparatus shown in Figs. 2, 3, 4, the base 12 being fastened to the slide block 34, Fig. 2.

In Fig. '1 I have shown schematically the system by which the impression cylinders are controlled in each of the printing units. The leader pipes 43, in the different printing units, connect with an upper output pipe 90, extending from a valve 8|, while leaders 44 connect with a lower output pipe 82 extending from valve 8|. Valve 8| is shown schematically as a simple reversing type of valve, having a reciprocating plunger type of gateway B3, normally held in a neutral position by any suitable means, such as springs (not shown). The plunger 83 is displaceable upwardly from its neutral position by a solenoid 86 and is displaceable downwardly from the neutral position by a solenoid 81 as will hereinafter appear.

A pump 88, operated by any suitable source of power, forces control fluid 89, which may be oil, water, or other preferably non-compressible liquid, through an intake 9|] from a storage tank 9|. Fluid under pressure is thus discharged from the pump into an upper pressure main 92. Pump 88 preferably includes an adjustable fluid pressure regulator 93 in the output side thereof so as to adjust the pressure of the fluid transmitted through pipe 92 to a suitable pressure input pipe or connection 94 of valve 8|. Leading from the lower portion of valve 8| is an exhaust pipe 95 for discharging fluid back to the storage tank 9|. The pressure regulator 93 may be adjusted to provide suitable pressure for the fluid supplied to the valve 8| as indicated by a pressure gauge 96. Whenvalve 8| is in its neutral position, a by-pass recess 91 is positioned to bridge between pressure pipe 94 and exhaust pipe 95, the output pipes 80, 82 being at the same time completely blocked by the plunger 83.

When solenoid 86 raises plunger 83 to this upper position an upper channel 98 provided in plunger 83 serves to connect pressure pipe 94 with pipe transmitting pressure to leaders 43 and causing pistons 39 and impression cylinders 24 to feed to the left to apply pressure toward the printing cylinders 23. Fluid relieved from the left end of chambers 4|] is discharged through leaders 44 and pipe 82 to a second channel 99 provided in plunger 83 and arranged to pass the fluid to the discharge pipe from which it is returned to the storage tank 9|. Deenergization of solenoid 86 and energization of solenoid 81 causes the plunger 83 to move to the other side of its neutral position, thus causing the pressure to be reversed in the chambers 40,

through pipes 43, 80, channel 99 and pipe 95,-

back to the storage tank 9|.

For the purpose of centralized control, to enable the operator of the printing press to instantly feed the impression cylinders in either direction, push button control switches I and I M, are provided. A plurality of the switches I 00 are connected in parallel and a plurality of switches IOI are connected in series with each other, a pair of switches I 00, IOI being positioned wherever it is desired to provide a control station. I have shown in Fig. 7 such stations located conveniently at each printing unit so as to permit of instant control while watching the machine at any unit.

When switch I00 is depressed, a circuit is closed from a suitable source of power I02,

through switch I00 and conductor I03 to a relay coil I04 and over a conductor I05 to source I02. This energizes the coil I04 and causes its armature I06 to move to a position which closes two normally open switches I01 and I08 and opens a normally closed switch I09, all of said switches being suitably insulated and mounted on the armature I06. A path may now be traced from the source of power I02, through the normally closed switch ml, to the lower contact of switch I08, the upper contact of said switch, coil I04, and conductor I05 back to the source I02, thereby forming a holding circuit for maintaining energization of coil I04, which holding circuit remains closed until button IN is depressed.

Another circuit may be traced from a second source of power IIO, through the upper and lower contacts of switch I01, to solenoid coil 86, conductor III, the contacts of a switch II2, back to the source IIO, thereby causing the energization of coil 86 which thereupon raises the valve plunger 83 from its neutral to its upper position. Relay coil I04 is maintained energized, by its holding circuit until push button IN is depressed, breaking the holding circuit traced above for th coil I04. De-energization of coil I04 causes switches I01, I08 and I09 to restore to normal in their left hand position, as actuated by the tension in a spring II3. This breaks the circuits of switches I01, I08 and closes a circuit traced from the source of power I02, contacts of switch I09, a conductor II4, contacts of the stop switch 68, a

.. relay coil II5 and back to the source I02, thus causing the energization of said relay coil II5, attraction of its armature I I6, and the closure .of an associated switch II1 which is normally held open by a spring I I8. A circuit may now be traced from the source of power I I0, through the lower and upper contactsof switch I I1, to solenoid coil 81, conductor III, to switch H2 and back to the source IIO, thereby energizing solenoid 81 and causing the attraction of valve plunger 83, downwardly from its neutral position,

and causing the fluid pressure to be transmitted through pipe 82 to withdraw the impression cylinder 24 from the printing cylinder 23.

It will be noted that when plunger 83 is moved to either side of its neutral position the by-pass recess 91 between pipes 94 and 95 is closed. Relay coil II5 and solenoid 81 remain energized to the right far enough to cause switch 68 to open its contacts.

The fluid pressure transmitted through pipe 43 to the chambers 40, in each printing unit 20,

2I, etc., may be separately adjusted by a pressure regulating valve I I9 which is arranged to permit fluid flow only in a direction toward chamber 40, as indicated by the arrow. Because of this,.a separate shunt path I20, including a one way valve I2 I, is provided to permit the control fluid to by-pass around valve H9, in the direction indicated by the arrow, when piston rod 39 is moved toward the right in response to fluid pressure transmitted through pipe 44 to chamber 40.

In each printing unit a shut off valve I22 is provided in pipe 43 for isolating that particular unit from centralized control by the buttons I00, I 0|. A pressure gauge I23, preferably having a scale reading directly in pounds per linear inch of the printing line, is connected to the pipe M to indicate the fluid pressure applied by the two piston chambers 40 and pistons 39 to the impression cylinder 24.

From the foregoing description, it will be seen that the described system of control permits the operator'to adjust the position of the impression cylinders at will, either by pressing the switch button I 00 to move the impression cylinders 24 toward the printing cylinders 23 to apply printing pressure on the web 22, or by pressing the switch button IM to withdraw the impression cylinders from the printing cylinders and remove ,the printing pressure on the web. By opening ing particularly applicable to intaglio printing, 1

it will be understood that the methods and equipment disclosed may be also usefully employed in' various other machines, such as typographic or planographic printing presses, embossing presses, machines for marking or operating on a web by other means or for treating a web with material other than ink and the like. It will also be understood that certain of the features of the invention, such as the centralized control; the rack and pinion mechanism; the arrangement for until button I00 is again depressed to energize relay I04 and open the circuit of relay II5 at the interlocking switch contacts I09, or until the piston rod 39 in printing unit 20 has withdrawn damping out vibrations, limiting the printing pressure and protecting the printing cylinder, and other features, may be applied to machines controlled by other than fluid pressure. Moreover, various changes and modifications of the methods and means specifically described, by way of illustration, may be made, and certain features or steps maybe employed without others, without departing from the invention or sacriflcing any of its advantages.

What I claim is: i

1. In a printing press, a printing cylinder, an impression cylinder for cooperating with said printing cylinder, means for guiding radial movement of each end of said impression cylinder in a predetermined path wherein said impression cylinder may be maintained closely parallel with said printing cylinder, separate means for each end of said impression cylinder for radially feed- 2. In a printing press, a printing cylinder, an

impression cylinder for cooperating with said.

printing cylinder, means for guiding radial movement of each end of said impression cylinder in a predetermined path wherein said impression cylinder may be maintained closely parallel with said printing cylindena separate fluid responsive means for each end of said impression cylinder for radially feeding said impression cylinder toward or away from said printing cylinder, and means responsive to said feeding means for maintaining said impression cylinder closely parallel with said printing cylinder.

3. In a printing press, a printing cylinder, an impression cylinder for cooperating with said printing cylinder, means for guiding radial movement of each endof said impression cylinder in a predetermined path wherein said impressioncylinder may be maintained closely parallel with said printing cylinder, a separate fluid pressure responsive means for each end of said impression cylinder for radially feeding said impression cylinder toward or away from said printing cylinder, and means including a separate rack and pinion mechanism for each end of said' impression cylinder, and a shaft connecting said pinions together for maintaining said impression cylinder closely parallel with said printing cylinder 4. In a printing press, a printing cylinder, an impression cylinder for cooperating with said printing cylinder, movable bearing blocks for said impression cylinder, means for guiding the movement of each of said bearing blocks in a predetermined path wherein said impression cylinder may be maintained closely parallel with said printing cylinder, a separate fluid pressure responsive means for each of said bearing blocks for feeding said blocks and said impression cylinder toward or away from said printing cylinder, and means responsive to said feeding means for maintaining said impression cylinder closely parallel with said printing cylinder.

5. In a printing press, a printing cylinder, an impression cylinder for cooperating with said printing cylinder, movable bearing blocks for said impression cylinder, means for guiding the movement of each of said bearing blocks in a predetermined path wherein said impression cylinder may be maintained closely parallel with said printing cylinder, a separate fluid pressure responsive means for each of said bearing blocks for feeding said blocks and said impression cylinder toward or away from said printing cylinder, a separate rack fast to each of said bearing blocks, a pinion for meshing with each of said racks, and a shaft rigidly connecting said pinions together in ,a position wherein said impression cylinder is closely parallel with said printing cylinder.

6. In a printing machine wherein there is provided a printing cylinder and an impression cylinder having a resilient rim for pressing the material being printed against the printing cylinder, a method of controllingthe printing pressure which comprises separately feeding each end of the impression cylinder toward the printing cylinder until a predetermined position is reached in which the desired printing pressure is exerted by each end of the impression cylinder on the sheet being printed, and damping out vi bration of the impression cylinder by blocking movement of the impression cylinder in a direction toward the printing cylinder beyond a point closer to the printing cylinder than said predetermined position, while yieldably pressing the impression cylinder in said blocked direction with a greater pressure than that between said cylinders.

'7. In a printing press, a printing cylinder and a cooperating impression cylinder, means for guiding radial movement of each end of said impression cylinder in a predetermined path wherein said impression cylinder may be maintained closely parallel with said printing cylinder, separate means for each end of said impression cylinder for radially feeding said impression cylinder toward or away from said printing cylinder, means responsive to said feeding means for maintaining said impression cylinder closely parallel with said printing cylinder, means common to said feeding means for causing the operation thereof, and means responsive to said common operating means for relieving the strain on said means for maintaining parallelism between said cylinders.

8. In a printing machine having at least two printing units in tandem for successively printing on a web, a printing cylinder and a cooperating impression cylinder in each of said units, means in each of said units for radially feeding said impression cylinder relatively to said printing cylinder, means common to all of said feeding means for causing the operation thereof, and means in one of said printing units for reducing the feeding speed of said impression cylinder therein to a value more nearly equal to that in the other of said units.

9. In a printing machine having a plurality of printing units in tandem for successively printing on a web, a printing cylinder and a cooperating impression cylinder in each of said units, means in each of said units for feeding said impression cylinder toward or away from said printing cylinder, means common to said printing units for controlling said feeding means, and means responsive to the feeding movement of said impression cylinder in one of said units for stopping the feeding movement of said impression cylinders in all of said units.

10. In a printing machine having a plurality of printing units in tandem for successively printing on a web, a printing cylinder and a cooperating impression cylinder in each of said units, means in each of said units for feeding said im--' pression cylinder toward or away from said printing cylinder, and means in one of said printing units responsive to withdrawal of said impression cylinder from said printing cylinder therein for stopping further withdrawal of the impression cylinders in all of said units.

ARTHUR M. WICKWIRE, JR.

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