Method And Means For Applying Liquid To A Moving Web

Abstract

A method and apparatus for applying a controlled quantity of liquid to a moving web of liquid receptive material comprising a smoothly finished hydrophilic transfer roller in rotative pressure engagement with the web. Pressure between a smooth surfaced metering roller and the transfer roller is adjustable to accurately control the thickness of a film of fluid having low viscosity which is delivered by the transfer roller to the web. The relative surface speeds of the transfer roller and the web are adjustable to control the rate at which the metered film is delivered to the web and to control the hydraulic pressure exerted to the film to urge it into the web. A backup roller is employed to further control the hydraulic pressure of fluid transferred to the web. The metering roller and the transfer roller are skewed to regulate the moisture profile across the width of the web.

Parent Case Text

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation-in-part of my copending application Ser. No. 600,650 filed Dec. 9, 1966, entitled "DAMPENING TRANSFER AND MATERIAL CONDITIONING ROLLER, AND METHOD OF PREPARING SAME," which is a continuation and copending with application Ser. No. 414,574, filed Nov. 30, 1964, now abandoned which was a continuation-in-part and copending with my application Ser. No. 26,035, filed May 2, 1960, now U.S. Pat. No. 3,168,037, which was a continuation-in-part of my copending application for U.S. Pat. Ser. No. 844,372, filed Oct. 5, 1959, entitled "DAMPENING OF LITHOGRAPHIC OFFSET PRINTING PLATES," now abandoned.

Description

BACKGROUND OF INVENTION

Attempts have been made in the past to add liquids such as dyes, low-viscosity coatings and moisture to a moving web in such a manner as to control the liquid application along the length and width of the web.

Such attempts have consisted of application of atomized particles in the form of mist, steam or spray to the web which results in only partial coverage of the web by the atomized particles or uneven application thereof and lack of adequate control of the amount and density thereof.

Another system used in the past is by means of rollers wherein an uncontrollable quantity of liquid is applied to the web.

Various other devices have been used such as scrapers, knives, blades, etc., as the sole means for controlling the thickness of liquid applied to the web from a roller, without other control means used in conjunction therewith, as disclosed herein. Such devices are undesirable because it is difficult to adjust flexible blades lengthwise and because the slightest adjustment of the blade may change the film thickness more than is desirable.

Environmental chambers, wherein a moving web is passed through a humid atmosphere within a chamber, have been unsatisfactory because only surface quantities are added to the web due to the limited time of exposure of the web to the humid atmosphere as it passes through the chamber. Thereby the web does not absorb sufficient quantity of the liquid. Furthermore, one side application is virtually impossible in this case.

Attempts to control moisture by varying web speed through drying devices or by varying the drying temperatures is not only difficult to control but undesirable and costly.

SUMMARY OF INVENTION

In use of the method and apparatus herein described, the liquid applied to the web is supplied from a reservoir or other liquid supply source to the nip between a smooth, resilient surfaced metering roller and a smoothly finished, hard surfaced hydrophilic transfer roller. An abundant supply of liquid is supplied at the nip between the rollers which is metered by pressure contact between the resilient surfaced metering roller and the hard surfaced transfer roller to an exactly controlled film which adheres to the surface of the hard transfer roller, which rotates into contact with the web to apply the liquid thereto.

As disclosed herein liquid application to the web can be carried out either by transferring the controlled film directly from the variable speed transfer roller on the web, or in accordance with an alternate form, it may be transferred to an intermediate web applicator roller rotating at web speed, which in turn applies a regulated film of liquid to the web.

Also as disclosed herein the variable speed transfer roller may be the resilient surfaced roller and the metering roller would be hard surfaced. The surface of the transfer roller is dependent upon surface characteristics of the web or web applicator roller.

For instance, if the web is metal or of other impervious material to be coated the roller in contact with the web should be resilient. However, in all applications it is desirable that the rollers should be alternately resilient and hard surfaced.

The term "transfer roller" as used herein means the roller which transfers a metered film of liquid to the web or intermediate applicator roller, regardless of its surface characteristic, and the term "metering roller" means the roller which rotates in pressure contact with the transfer roller to meter a film of liquid thereon.

Means is provided for adjusting the pressure at the roller ends between the resilient metering roller and the hard-surfaced hydrophilic transfer roller to thereby vary the film thickness.

Additional means is provided for adjusting and varying the contact pressure between the ends of the rollers as related to the central portions thereof, which is commonly referred to herein as "skew" or "skewing." Such skewing is accomplished by radially moving an end of one of the rollers arcuately about the longitudinal axis of the other roller to thereby adjust and control contact pressure longitudinally of the contacting surfaces of the rollers. By such means roller core deflection may be compensated for and uniform, or nonuniform liquid film thickness, as desired, is provided for throughout the length of the system.

The controlled lengthwise liquid film is applied directly to the web or through a web applicator roller at a controlled uniform and desired rate by controlling and varying the surface speed of the transfer roller with relation to the adjacent surface speed of the web or additional applicator roller employed. To accomplish this purpose the transfer roller on which the metered and regulated liquid film is carried is driven by a positive drive means so that its surface speed can be varied as desired, either manually or automatically, to transfer a uniform continuous desired quantity of liquid onto the web or web applicator roller as the case may be.

The surface speed of the transfer roller may be less than, equal to, or greater than the surface speed of the adjacent web or web applicator roller, depending upon the liquid quantity desired for the web.

The metering roller may also be driven by a variable speed positive control. The surface pressure between the metering and transfer roller and the speeds of rotation thereof may be adjusted to supply the desired metered film of liquid to produce a continuous metered liquid film on the transfer roller surface.

In cases where the liquid must immediately penetrate the web or where higher quantities of liquid are to be added, or where the web must be pressed firmly against the transfer or applicator roller for any reason, a backup roller driven at web speed may be applied to the opposite side of the web from the transfer or applicator roller to press the web thereagainst at such point, to thereby cause the liquid to penetrate or adhere to the surface of the web. Uniform pressure between the web and the transfer or applicator roller can also be accomplished by one or more adjacent idler rollers rolling in contact with the web on the opposite side of the web from the transfer or applicator roller. Uniform pressure may also be applied by other means such as wrapping the web about the transfer or applicator roller. Additional web wrap on the transfer roller or applicator roller can also serve to increase dwell time of web to roller surface thereby adding to capability of the system. Uniform pressure may also be accomplished by placing an applicating device with a transfer or applicator roller on the opposite side of the transfer roller or applicator roller of another liquid applying system, thereby applying liquid to each side of the web by a separate liquid applicating system.

The most popular use of the method and apparatus disclosed herein is for adding and controlling moisture applied to paper and paperboard, both on original paper making equipment and on paper converting equipment. The compact design enables the equipment in many cases to be installed in the normal web stream as the paper comes through the paper making or converting machine. In the manufacture and processing of the paper web, the paper is usually depleted of moisture to an extent that a controlled amount of moisture can be added thereto. Reasons for desiring controlled liquids is described below.

On a paper or paperboard web material, moisture or a mixture of liquids may be added to the paper web in controlled quantities to condition same, to control the curl, cockle (tendency to buckle), weight, sizing, absorbency capacity, moldability, gloss, surface finish, tensile strength, electric and thermal conductivity, ability to receive ink, cohesion, adhesion, pH, stress relief (tension), web speed control, dimensional stability and others.

Although the method and device is particularly usable in adding moisture to paper or paperboard, it will be understood that it can be used to control and apportion the addition of dyes, coating material, liquid plastics, glue, starch, waxes and other low-viscosity liquids desired to be applied to the surface of a web whether pervious or impervious.

The equipment employed is very flexible in that it may be simple or complex depending upon the particular user's requirements. For instance, in one of the simplest and most economical forms it may include the basic elements of positive control of speed of rotation of the transfer roller with relation to the speed of movement of the web or with relation to the speed of rotation of the intermediate applicator roller, control of linear thickness of the moisture film metered between the transfer roller and the metering roller by adjustments at the metering roller ends coupled with skewing; or the system may incorporate automatic and remotely controlled features which may include means to automatically engage and disengage liquid application to the web; automatic increase and decrease following circuitry to maintain desired liquid application to compensate for changes of moisture or changes in web speed; automatic shutdown resulting from lack of sufficient liquid supplied to the system, motor overload or web break; electropneumatic roll engagement and/or disengagement; remote speed control and indication; servo actuated metering roll adjustment; automatic liquid level control in the reservoir and many other types of controls and adjustments.

Surface speed of the transfer roller may be less than, equal to, or greater than the surface speed of the adjacent web or web applicator roller, according to liquid quantity demand. Rotation of the transfer roller may be in the same or opposite direction to that of the adjacent web or applicator roller.

In the system hereinafter described, both the transfer and metering rollers are driven by positive means. The metering roller rotates in contact with the variable speed transfer roller and is the roller which is adjusted to control the desired metered film of liquid. The metering roller need only be driven at a speed sufficient to produce a continuous metered liquid film on the transfer roller surface which is transferred to the web in the desired quantity, depending upon the adjusted speed of rotation of the transfer roller.

Other and further objects and advantages of the invention will become apparent upon reading the detailed specification hereinafter following and by referring to the drawings annexed hereto.

DESCRIPTION OF DRAWING

Suitable embodiments of the invention are shown in the attached drawings wherein,

FIG. 1 is a semidiagrammatic end view of the simplest form of the device, wherein the special transfer roller is rotated in contact with a web of paper or other material to which liquid is being applied and showing the means for rotating the transfer roller at a variable speed;

FIG. 2 is a semidiagrammatic end view of a form of the device wherein a resilient surfaced metering roller is interposed between the transfer roller and the liquid to transfer liquid to the transfer roller in a metered film, and showing means to adjust and control the speed of rotation of both the transfer roller and the metering roller;

FIG. 3 is a side elevational view of the metering roller and transfer roller of FIG. 2, showing the difference in length between the metering roller and transfer roller, their relationship to the web, and the means for skewing the metering roller with relation to the transfer roller;

FIG. 4 is an end view of another modified form of liquid applying device wherein a backup roller is added for rotation in contact with the web on the opposite side thereof from the transfer roller;

FIG. 5 is a side elevational view of the form shown in FIG. 4 showing the variation in length between the respective rollers, their relationship to the web, and the means for skewing the metering roller with reference to the transfer roller;

FIG. 6 is an end view of still another form of liquid applicator device showing the employment of spaced web guide rollers with means to shift the applicator roller out of engagement with the web;

FIG. 7 is an end view of still another modified form of the device wherein an applicator roller is interposed between the variable speed transfer roller and web with means to separate the transfer roller from the applicator roller;

FIG. 8 is a cross-sectional side elevational view of the transfer roller and metering roller in adjusted contact, illustrating the relative linear pressure between the contacting surfaces of the rollers after they have been skewed and pressure adjusted with relationship to each other, and

FIG. 9 is an end view of the transfer roller and metering roller as it would appear before and after skewing the metering roller with relationship to the transfer roller,

FIG. 10 is a side elevational view of the roller and web assembly of FIG. 7 .

DESCRIPTION OF PREFERRED EMBODIMENTS

Numeral references are employed to indicate the various parts as shown in the drawings and like numerals indicate like parts throughout the various figures of the drawings.

Referring first to the form shown in FIG. 1, the numeral 1 indicates a liquid container with a quantity of liquid 2 therein. The liquid may be moistening fluid such as water with other ingredients added thereto, such as material to lower the surface tension of the water, or it may be other types of liquid such as plastic or other type of coating material to be added to the web 11.

A specially prepared transfer roller 3 is of a type which has a hard, smooth surface thereon having minimum surface indentations, scratches or blemishes thereon and is preferably treated to render same hydrophilic, that is, liquid receptive and grease rejecting.

The transfer roller 3 may be of the type described in my previous U.S. Pat. No. 3,168,037, which includes a metal roller, such as steel, which is plated with a hard surfacing material such as chrome or nickel and is polished by buffing or otherwise to provide a smooth uninterrupted surface thereon free of surface blemishes, insofar as possible.

It will be understood that the surface of the transfer roller 3 may be made of other materials which may be applied thereto with a smooth uninterrupted surface thereon and which may be provided with hydrophilic properties, either when applied thereto or which may be treated to render same hydrophilic.

A chrome or nickel plated surface may be treated in the manner described in my previous patent aforementioned by bathing same with a passivating agent such as hydrochloric or sulphuric acid mixed with water and gum arabic in equal proportions for sufficient length of time to remove all oxide from the surface thereof and apply an oxide preventing coating of gum arabic thereto.

The transfer roller 3 is rotated with the lower side thereof submerged in the liquid 2 so that liquid is picked up on the surface thereof as it rotates therethrough.

The transfer roller 3 is rotated by an electric motor 6 which drives the belt 4 which is extended about a sheave 5 attached to the shaft 23 on which the transfer roller 3 is mounted and the sheave 7 secured to the shaft 6a rotated by the motor 6.

Power supply lines 8 supply power for driving the motor 6 through a variable rheostat 9 so that the motor 6 may be run at variable speeds to thereby rotate the transfer roller 3 at variable speeds.

A doctor blade 10 which may be varied in pressure relationship against the surface of the transfer roller 3 is arranged to bear against the surface of the transfer roller 3 as it rotates out of the fluid 2 to thereby wipe off excess liquid clinging to the surface of the roller and to smooth out the film of liquid adhering to the surface of the roller before the film is rotated into contact with the moving web 11.

The surface of the transfer roller 3 rotates in contact with the moving web 11 to apply liquid thereto. The moving web 11 may be a web of paper to which moisture is to be added, or it may be a sheet of fabric or solid material such as plastic or metal to which a coating liquid such as plastic, starch, glue or other material is to be added. Speed of rotation of the transfer roller 3 with relation to speed of movement of the web 11 may be varied by varying the speed of the motor 6 through the rheostat 9, thereby varying the rate of application of the film of liquid to the moving web 11. The rate of application of liquid to the web may be minutely adjusted by varying the speed of rotation of the transfer roller 3 with relation to the speed of movement of the web 11. Normally the speed of movement of the web 11 is constant and therefore the speed of rotation of the transfer roller 3 may be adjusted with relation to the constant speed of movement of the web 11 to thereby regulate the application of moisture or other liquid material to the web 11 to the exact amount desired.

By virtue of the fact that the film of liquid is made constantly present between the surface of the transfer roller 3 and the web 11 the unused film of liquid provides a lubricating fluid which reduces friction between the surface of the transfer roller 3 and the web 11 to such an extent as to permit the transfer roller 3 to be rotated at a different surface speed than the movement of the web 11 to thereby permit slipping contact between said surfaces without frictional damage.

All unused liquid not accepted by the web 11 returns to the liquid reservoir without affecting the liquid being transferred to the web.

As will be seen from the arrows indicating direction of movement of the transfer roller 3, the transfer roller 3 may be rotated in either direction with relation to the movement of the web 11 and accomplish the same purpose. However, in the event transfer roller 3 is rotated in the direction of the broken arrow shown thereon the doctor blade 10 will of course be placed on the opposite side of the transfer roller 3.

In the modification shown in FIG. 2 the transfer roller 3 is the same type hereinbefore described but runs in pressure contact with a resilient surfaced metering roller 12.

The metering roller 12 is covered with resilient rubber or plastic material and is arranged to be adjusted in indenting relationship with the transfer roller 3. The roller 12 has a smooth, uninterrupted surface thereon.

The roller 12 is rotated by electric motor 17 which is supplied by power through the power leads 18, and the speed of motor 17 may be regulated by a rheostat 18a. The roller 12 is driven by the motor 17 through a belt 19 which extends about the pulley 20 attached to the shaft of the motor and pulley 21 secured to the axle 13 of the roller 12.

The pressure relationship between the surfaces of the transfer roller 3 and metering roller 12 may be adjusted by a screw 15 which threadedly extends through the end of bracket 14. Bracket 14 is secured to a fixed member such as the frame of the machine as indicated at 54 in FIG. 8. The inner end of the screw 15 contacts a block 13a in which self-aligning bearings 5a and 5b are mounted. Bearings 5a and 5b rotatably support axle 13 of roller 12 and said block 13a is slidably disposed in a slot 14a provided in the bracket 14. A spring 16 is interposed between the block 13a and the end of the bracket 14 so that as the screw 15 is threaded inwardly the roller 12 is moved toward the transfer roller 3 to increase the pressure between the surface of the roller 12 and transfer roller 3 and at the same time contracts the spring 16. The spring 16 causes the roller 12 to be resiliently urged against the screw 15 so that the roller 12 in effect is stabilized with relation to the transfer roller 3. One end of the shaft 23, supporting the transfer roller 3, is pivotally attached to one end of the shaft 13, supporting the metering roller 12, by means of an arm 22 secured at one end to bracket 14. The other end of arm 22 is pivotally secured about one end of the shaft 23. This arrangement permits the end of the roller 12 to be arcuately rotated about the transfer roller 3 to thereby cause the resilient surface of the roller 12 to be spiralled about the surface of the transfer roller 3 to thereby distribute pressure between the contacting surfaces of the rollers 12 and 3 to thereby provide for uniform or nonuniform pressure as desired between the ends of the rollers 12 and 3, as will be described in more detail with reference to FIG. 8. The ends of the axle 13 of roller 12 are, as mentioned above, mounted in self-aligning bearings 5a and 5b. By self-aligning bearings is meant a bearing mounted so that the support therefor will rotate and align the axis thereof with the axis of the shaft which it supports. Such bearings are of conventional construction.

As liquid 2 is picked up from the container 1 on the surface of the roller 12 it is carried on the surface of roller 12 to the nip between the rollers 12 and 3. Such liquid forms as an abundant supply on one side of the nip but is compressed between the contacting pressure surfaces between rollers 12 and 3 and is metered in a uniform, evenly distributed film of liquid onto the surface of transfer roller 3. Such metered uniform film is carried on the surface of the transfer roller 3 to the contacting surfaces between the transfer roller 3 and the web 11 and is thus transferred from the transfer roller 3 to the web 11.

As hereinbefore explained the speed of rotation of the transfer roller 3 may be regulated by the rheostat 9 to thereby transfer the required amount of liquid to the surface of the moving web 11 in the manner hereinbefore described with reference to FIG. 1.

By adjustment of the screw 15 the thickness of the metered film of fluid carried on the surface of the transfer roller 3 to the web 11 may be regulated as required by the particular job.

The speed of rotation of the roller 12 may be regulated by the adjustment of the rheostat 18a in order to pass the required amount of liquid from the reservoir 1 to the nip between the rollers 12 and 3. The amount of liquid picked up by roller 12 and presented to the roller nip should always be more than that passed between rollers 12 and 3, and any excess will fall back into pan 1. Normally the speed of rotation of the roller 12 will be constant after setting, and the application of liquid to the web 11 will be controlled by the adjustment of the speed of rotation of the transfer roller 3.

Thereby it will be seen that the amount of liquid applied to the web 11 may be accurately and exactly controlled by the adjustment of the speed of rotation of both the rollers 12 and 3 and such control may be maintained by adjustment of the speed of rotation of the transfer roller 3 with reference to the moving web 11. Normally the transfer roller 3 will be run at a different surface speed from the web 11 and will be in slipping relationship thereto, with the film of liquid providing an antifriction lubricant therebetween as hereinbefore explained.

It will be noted in FIG. 3 that both rollers 3 and 12 are longer than the web 11 and roller 12 extends beyond the ends of the transfer roller 3. Such arrangement has a definite function in that it has been found that liquid has a tendency to collect at the ends of the roller 12. By extending the ends of the roller 12 beyond the ends of the transfer roller 3 and the ends of the roller 3 beyond the web 11, the excess liquid accumulated at the ends of the roller 12 will fall back into the reservoir 1 and will not be transferred on the surface of the transfer roller 3 to the edges of the web 11 in excess quantities.

In the form shown in FIG. 4, a backup roller 24 is added to the combination shown in FIG. 2. The backup roller 24 is rotated in the same direction as web 11, at web speed, and has a resilient surface, such as rubber or plastic, thereon and is arranged to rotate in adjusted pressure relationship against the web 11 as the web moves between the nip between the rollers 3 and 24.

The pressure relationship between the web 11 and transfer roller 3 therebehind as related to the backup roller 24 may be adjusted by a screw 28 threadedly engaged through the end of the bracket 26. The screw 28 bears against a block 25a attached to the axle 25 of the roller 24. The block 25a is slidably disposed in a slot 26a in the bracket 26 and the movement thereof is limited by an adjustable screw 27 engaged between the end of the bracket 26 and the block 25a so that the roller 24 may be adjusted in pressure relationship to the web 11. The backup roller 24 is applied to the web 11 primarily to cause the liquid to penetrate and be more quickly absorbed by the web 11 as it passes through the pressure nip between the rollers 3 and 24. As will be seen in broken lines the roller 24 is preferably arranged to be shifted out of contact with the web 11 if desired.

As shown in broken lines in FIG. 4 the web indicated as 29 could be arranged to wrap the backup roller in lieu of the transfer roller if desired.

The rollers 12 and 3 bear the same relationship and function the same as described in connection with the embodiment shown in FIG. 2, the transfer roller 3 being arranged to be rotated at variable speed to regulate the amount of liquid applied to the web 11 or 29.

As shown in FIG. 5 the ends of the rollers 12 and 3 extend beyond the ends of the web 11 and roller 12 extends beyond the ends of roller 3 to prevent excess fluid from being transferred to the ends of the transfer roller 3 and from thereto to the edges of the web 11, as hereinbefore explained with reference to FIG. 3. It is further shown that backup roller 24 extends beyond the web 11 to apply pressure to maximum web width.

In the form shown in FIG. 6, the web 32 is maintained in pressure relationship with the surface of the transfer roller 3 by guide rollers 30 and 31. Otherwise the relationship and function of the rollers 12 and 3 are the same as hereinbefore described with the exception that, as shown in broken lines, the transfer roller 3 is arranged to be shifted out of contact with the web 32 if desired.

It will further be seen that in the forms of FIGS. 2-6 one end of the roller 12 is pivotally attached by arm 22 to the end shaft 23 of the transfer roller 3 so that the end of the roller 12 may be arcuately moved about the axis of the transfer roller 3 to spiral the resilient surface of the roller 12 about the transfer roller 3 to provide uniform or nonuniform pressure as desired between the surfaces of the rollers 12 and 3 as will be hereinafter explained. The axle 13 of roller 12 passes through an elongated passage 22a in arm 22 to accommodate relative movement therebetween when roller 12 is moved for adjustment in pressure relationship to roller 3.

As in the previous embodiments hereinbefore described the speed of the transfer roller 3 may be regulated as it rotates in contact with the moving surface of the web 32 in order to regulate the amount of liquid applied to the web 32. The surface speed of the transfer roller 3 may be the same or different from the speed or movement of the web 32, but if different, the unused liquid on the surface of the transfer roller 3 provides a lubricant to prevent frictional damage to the web 32 as it moves in slipping contact with the surface of the transfer roller 3.

In the embodiment shown in FIG. 7 the hard surfaced supply roller 33 which may be of the same type as roller 3, hereinbefore described, rotates in the liquid 2 in the reservoir 1 and rotates in surface contact with a resilient surfaced variable speed transfer roller 34 which is the same type as roller 12 hereinbefore described.

The hard surfaced roller 33 in this form is the metering roller and may be adjusted in surface pressure relationship with the transfer roller 34 by means of a screw 43 which threadedly passes through the end of a bracket 42 and engages a block 41a which holds self-aligning bearings such as 5a and 5b supporting the axle 41 of the roller 33. Bracket 42 at one end of roller 33 is affixed to the machine frame as was described with relation to bracket 14 and at the other end of roller 33 is movable with the suspension arm 45. The block 41 may be slidably moved in the slot 42a by threading the screw 43 inwardly to thereby increase the pressure relationship between the metering roller 33 and the surface of the transfer roller 34. The block 41a is moved inwardly against the spring 44 so that the roller 33 is stabilized with relationship to the roller 34. The axle 41 passes through an elongated passage in the suspension arm 45 to permit relative movement therebetween.

The transfer roller 34 is rotated by a motor 35 which drives same through a belt 38 extending about the pulleys 46 and 35a. Power is supplied to the motor 35 through the power leads 36, and the speed of motor 35 may be controlled by the variable rheostat 37.

Roller 33 is driven by belt 39 through pulley 40 and may also be driven by a variable speed motor.

An intermediate applicator roller 47 is driven by frictional contact between the web 48 and roller 47 and the amount of liquid transferred to the surface thereof and ultimately to web 48 is regulated by the regulation of speed of rotation of the transfer roller 34. The surface pressure relationship between rollers 47 and 34 may be adjusted as desired by a mounting of the end axles of one of the rollers by an adjustment bracket such as bracket 14 secured to a fixed frame member as shown in FIGS. 2 and 8.

The thickness and uniformity of the film of liquid passed from the nip between the rollers 33 and 34 is regulated by the pressure adjustment between the surfaces of said rollers as hereinbefore described. The metering roller 33 may be skewed with relationship to the surface of the transfer roller 34 by arcuately rotating an end of the pan roller 33 with reference to the axis of the transfer roller 34 by the link 45 which is pivotally attached to the axles of the rollers 33 and 34.

A resilient backup roller 24, previously described may also be provided in the assembly of FIG. 7.

FIG. 10 shows the relative lengths of the rollers in FIG. 7. It will be noted that the rollers are progressively longer from the topmost down for the reasons hereinbefore described and that the ends of applicator roller 47 and backup roller 24 extend beyond the edges of the web 48.

The skewing function is illustrated in FIGS. 8 and 9. By "skewing" it is meant that the surface pressure between the transfer roller 3 and the metering roller 12 is adjusted lengthwise.

It has been found that when two rollers of considerable length are placed in surface pressure relationship the rollers have a tendency to deflect or bow so that the pressure is greater at the ends than in the middle thereby allowing excess fluid to pass between the rollers toward the middle. This condition is aggravated by the fact that paper is usually drier at the edges and wetter toward the center thereby necessitating that a means be employed when controlling moisture to correct for roll deflection as well as uneven moisture profile in the oncoming web.

In the combination of the hard surfaced roller 3 and the resilient surfaced roller 12, as employed herein, it has been found that such uneven pressure and/or web profile can be adjusted and exactly regulated by pivotally attaching the axle of one end of one of the rollers to the adjacent axle of the end of the other roller so that the end of the resilient surfaced roller can be arcuately moved about the axis of the hard surfaced roller or vice versa to thereby spiral the resilient surface of the metering roller about the hard surface of the transfer roller to thereby adjust and distribute the surface pressure relationship lengthwise of the rollers. In such arrangement it is necessary that the roller 12 have a rigid, preferably metallic, core 49 and that the transfer roller 3 have a rigid core 3b so that in arcuately moving the end of the roller 12 about the adjacent end of the transfer roller 3 the cores of the rollers are not excessively bent or deflected but on the other hand only the resilient surface 50 on the metering roller 12 is spirally twisted about the hard surface of the transfer roller 3. Thereby the pressure toward the center of the contacting surfaces of the rollers becomes greater, as indicated at 51 with relationship to the pressure at the ends thereof. This manner of surface adjustment permits the pressure to be adjusted intermediate roller ends without disturbing the pressure at the ends.

Thereby it will be seen by broken lines at 52, and unbroken line indicated at 53 that the surface pressure between the resilient surface 50 of the metering roller 12 and the hard surface of the transfer roller 3 can be adjusted throughout the length of the contacting surfaces. Thus a desired distributed thickness of liquid film is passed between the nip of the metering roller 12 and the transfer roller 3.

As shown in FIG. 9 one end of the roller 12 is arcuately moved with reference to the adjacent end of the transfer roller 3, and opposite ends thereof assume different positions after the skewing operation as hereinbefore described.

As shown in FIG. 7 the hard surfaced metering roller 33 may be skewed with reference to resilient surfaced transfer roller 34 and accomplish the same purpose.

It will be understood that the position of rollers 3 and 12 and 33 and 34 could be interchanged in which case the applicator roller 47 would be a resilient roller and backup roller 24 would be a hard roller. The metering roller in FIGS. 2-6 would thus be hard and the transfer roller would be resilient and the reverse of this would be true in FIG. 7.

It will be further understood that even though the rollers are referred to as being "hard" and "resilient," these are only relative terms and both could actually be made of the same material such as plastic or rubber which would be resilient material but the relative hardness might be different. The surfaces could still be adjusted in indented relationship to provide for the metering of a regulated film of liquid therebetween.

It will be seen that I have provided means for transferring liquid to a moving web in regulated quantity and uniform or nonuniform lateral distribution as desired wherein the amount of moisture or other liquid may be regulated by varying the speed of rotation of a transfer roller in contact with a moving web or intermediate web applicator roller, wherein the amount of liquid may be passed to the transfer roller in regulated thickness and with desired distribution across this roller by metering same between a resilient surfaced roller and a hard surfaced roller and wherein an uneven distribution to the web caused either by lateral deflection of the metering roller and transfer roller in contact or by an uneven moisture profile in the web may be compensated for by spirally twisting the surface of one roller about the surface of another roller, which is simple and efficient in its operation and provides for versatility in adjustment and use for applying different types of liquid to a moving web in regulated quantities.

Claims

Having described my invention I claim:

1. In a device for applying liquid to a moving web of liquid receptive material, a liquid carrying transfer roller having a continuous, uninterrupted, smoothly finished, liquid receptive hydrophilic surface rotating in pressure contact with the web; means to continuously supply liquid to the surface of the liquid carrying transfer roller before it rotates into contact with the web; metering means in pressure engaging relation with the surface of the transfer roller to limit the thickness and smooth out the film of liquid on the surface before it comes into contact with the web; means to vary the pressure between the metering means and the transfer roller; and means to vary the relative surface speeds of the transfer roller and the web to cause slippage therebetween to evenly distribute and regulate the quantity of liquid applied by the transfer roller to the web.

2. The combination called for in claim 1 wherein the means for limiting the film of liquid is a doctor blade in pressure engagement with the surface of the transfer roller.

3. The combination called for in claim 1, wherein the means for limiting the film of liquid is a metering roller having a smooth surface in pressure relationship with the surface of the transfer roller before the surface of the transfer roller moves into contact with the web.

4. In a device for applying liquid to a moving web of material having a liquid receptive surface thereon, a liquid carrying transfer roller having a smooth liquid receptive surface thereon running in pressure contact with one surface of the web, said surface on the transfer roller having an affinity for the liquid carried thereby to cause the liquid to spread in a continuous layer of substantially uniform thickness on the surface of the transfer roller; a metering roller having a smooth liquid receptive surface; at least one of said metering or transfer roller having a resilient surface, whereby they are in indented surface pressure relationship; means to vary the relative surface speeds of the transfer roller and the web; and means to supply liquid at the contacting surfaces of the metering roller and transfer roller.

5. The combination called for in claim 4 with the addition of means to vary the relative surface speeds of the transfer roller and metering roller.

6. The combination called for in claim 5 wherein the means to vary the relative surface speeds of the transfer roller and metering roller is a variable speed drive member positively controlling the metering roller speed.

7. The combination called for in claim 4 wherein the means to vary the relative surface speeds of the transfer roller and the web is a variable speed drive member positively controlling the transfer roller speed.

8. The combination called for in claim 7 with the addition of means to move an end of one of the rollers circumferentially about an end of the other roller to spirally twist the resilient surface of the resilient surfaced roller about the surface of the other roller to thereby adjust and control contact pressure longitudinally of the contacting surfaces of the rollers without varying the pressure between the ends of the respective rollers.

9. The combination called for in claim 4 with the addition of a backup roller rolling in pressure contact with the surface of the web opposite the surface contact between the web and the transfer roller.

10. The combination called for in claim 9 wherein the ends of the transfer roller, backup roller and metering roller extend beyond the edges of the web.

11. The combination called for in claim 4 with the addition of guide rollers running in contact with the web to hold the web against the transfer roller.

12. The combination called for in claim 11 wherein the guide rollers control the arc of contact of the web to the transfer roller.

13. The combination called for in claim 4 wherein the ends of the metering roller extend beyond the ends of the transfer roller.

14. The combination called for in claim 13 wherein the ends of the transfer roller and metering roller extend beyond the ends of the web.

15. The combination called for in claim 4 wherein the means to supply liquid at the contacting surfaces of the metering roller and transfer roller comprises a liquid reservoir with one of the metering or transfer rollers having one side immersed in liquid in said reservoir and the other side in indented surface contact with the surface of the other roller.

16. The combination called for in claim 15 with the addition of means to move an end of one of the rollers about the axis of the other roller to spirally twist the resilient surface of the resilient surfaced roller about the surface of the other roller to thereby adjust and control contact pressure longitudinally of the contacting surfaces of the rollers.

17. In a device for forcing moisture under pressure into a moving web of absorptive material, a liquid carrying fluid transfer roller having a continuous, uninterrupted, hard, smoothly finished hydrophilic surface thereon rotating in pressure contact with the web; a metering roller having a smooth resilient surface thereon in rotative contact with the surface of the transfer roller and adapted to be indented in metering relationship with the transfer roller to control the thickness of a film of fluid carried by the transfer roller to the web; variable speed drive means drivingly connected to the surface speeds of the transfer roller and the web; means to supply fluid at the contacting surfaces of the metering roller and the transfer roller; and means to adjust the surface pressure relationship between the transfer roller and the metering roller.

18. The combination called for in claim 17 with the addition of means in pressure engagement with the web to vary the surface pressure relationship between the transfer roller and the web.

19. The combination called for in claim 18 wherein the means to vary the surface pressure relationship between the transfer roller and the web comprises, a backup roller having a smooth surface thereon in pressure contact with the surface of the web opposite the surface of contact between the web and the transfer roller; and means to vary the surface pressure relationship between the backup roller and the web.

20. The combination called for in claim 17 with the addition of an arm; means to rotatably secure the metering roller to the arm; means to rotate the arm about the axis of the transfer roller to vary the surface pressure relationship between the metering roller and the transfer roller along the length thereof.

21. In a device for applying liquid to a moving web, a metering roller having a continuous, uninterrupted, hard, smoothly finished hydrophilic surface thereon; means to apply liquid to the surface of the metering roller; an applicator roller having a smoothly finished surface in pressure contact with the web; roller means in pressure indented rolling contact with the metering roller and the applicator roller for transferring a metered film of fluid to the applicator roller; and means to vary the surface speed of at least one of the rollers relative to the surface speed of the web.

22. In a device for applying liquid to a moving web, an applicator roller having a smooth surface in rotative contact with the web; a transfer roller having a smooth surface in indented surface pressure relation with the applicator roller, a metering roller having a smooth surface in indented surface pressure relation with the transfer roller, at least one of said rollers having a smooth liquid receptive surface adapted to cause liquid to tend to spread uniformly thereover; means to supply liquid at the contacting surfaces of the metering and transfer roller; means to vary the surface speed relation of at least one of the rollers relative to the surface speed of the web; means to vary the surface pressure relationship between the metering roller and the transfer roller; and means to vary the surface pressure relationship between the transfer roller and the applicator roller.

23. In a device for applying liquid to liquid receptive material, a first roller having a continuous, uninterrupted, hard, polished, hydrophilic surface thereon; a second roller having a smooth resilient, surface thereon in rotative contact with the surface of the first roller, and adapted to be indented in metering relationship with the first roller; means to supply liquid at the contacting surfaces of the first and second rollers; means to vary the surface speed relationship of the first and second rollers to control the thickness of a film of liquid metered therebetween; means in indented surface contact with one of the rollers to rotate the metered film into contact with the liquid receptive material.

24. In a device for applying moisture to a moving web of liquid receptive material, a transfer roller having a smooth metallic surface; a coating on the surface to prevent oxidation of the surface and to render same permanently hydrophilic; means to apply fluid to the surface of the transfer roller; means in pressure relation with the transfer roller to form a film of fluid of metered thickness; means to rotate the film into contact with the web; and means to vary pressure between the web and the film to control the rate at which moisture is accepted by the web.

25. The combination called for in claim 24 wherein the means to rotate the film into contact with the web comprises drive means to rotate the said transfer roller.

26. The combination called for in claim 24 wherein the means to rotate the film into contact with the web comprises at least one roller having a surface which is less resilient than the surface of said transfer roller.

27. In a device for applying liquid to a moving web of liquid receptive material, a liquid carrying transfer roller having a continuous, uninterrupted, smoothly finished, liquid receptive hydrophilic surface rotating in pressure contact with the web; means to continuously supply liquid to the surface of the liquid carrying transfer roller before it rotates into contact with the web; means to vary the relative surface speeds of the transfer roller and the web to cause slippage therebetween to evenly distribute and regulate the quantity of liquid applied by the transfer roller to the web; and a backup roller having a smooth surface rolling in pressure contact with the surface of the web opposite the surface contact between the web and the transfer roller.

28. The combination called for in claim 27 wherein the contacting surfaces of the transfer roller and the web move in opposite directions.

29. In a device for applying liquid to a moving web of material having a liquid receptive surface thereon, a liquid carrying transfer roller having a smooth hydrophilic liquid receptive surface running in pressure contact with one surface of the web; a metering roller having a smooth liquid receptive surface in indented pressure contact with the surface of the transfer roller, the metering roller and the transfer roller being arranged to meter a film of aqueous liquid; at least one of said metering or transfer roller having a smooth resilient surface; means to vary the surface pressure relationship between the metering roller and the transfer roller; means to vary the relative surface speeds of the transfer roller and the web; and means to supply liquid at the contacting surfaces of the metering roller and transfer roller.

30. In a device for metering and applying liquids having waterlike viscosities to a web of liquid receptive material; a transfer roller in pressure contact with the web of material; a metering roller in pressure indented relation with the transfer roller, at least one of said rollers having a resilient surface; means to supply liquid at the contacting surfaces of the metering and transfer rollers; a skew arm having an end of the metering roller and an end of the transfer roller rotatably mounted therein; means to move an end of at least one of the rollers longitudinally of the skew arm to establish and maintain a predetermined pressure between contacting surfaces adjacent ends of the transfer and metering rollers, said skew arm being rotatable about an axis of one of said rollers to adjust and control pressure intermediate the ends of the contacting surfaces of said rollers with reference to a preestablished pressure between contacting surfaces at the ends thereof, said resilient surface being spirally twisted about the surface of the other roller; and means to rotate the rollers.

31. The combination called for in claim 30 with the addition of means to vary the surface speed of the transfer roller relative to the surface speed of the web of liquid receptive material.

32. The combination called for in claim 30 wherein the contacting surfaces of the transfer roller and the web of liquid receptive material move in opposite directions.

33. The combination called for in claim 30 wherein contacting surfaces of the metering roller and transfer roller move in opposite directions.

34. The combination called for in claim 30 with the addition of means to control pressure between the transfer roller and the web of liquid receptive material.

35. The combination called for in claim 30 wherein the transfer roller has a surface with hydrophilic properties.

36. The combination called for in claim 30 wherein the metering roller has a surface adapted to cause liquid to spread into a substantially smooth film thereover.

37. In a device for applying liquid to a moving web of liquid receptive material, a transfer roller in pressure contact with the web, said transfer roller having a smooth resilient surface; a metering roller in pressure indented relation with the transfer roller, said metering roller having a smooth surface adapted to cause liquid to tend to spread in a substantially uniform layer thereon; and means to vary the relative surface speeds of the transfer roller and the web.

38. In a device for applying liquid to a moving web of liquid receptive material, a transfer roller in pressure contact with the web, said transfer roller having a smooth resilient surface; a metering roller in pressure indented relation with the transfer roller, said metering roller having a smooth uninterrupted surface with hydrophilic properties to cause liquid to tend to spread in a substantially uniform layer thereon; and means to vary the relative surface speeds of the transfer roller and the metering roller.

39. In a device for applying liquid to a moving web of material having a liquid receptive surface thereon, a liquid carrying transfer roller having a smooth liquid receptive surface thereon running in pressure contact with one surface of the web, said surface on the transfer roller being adapted to cause liquid to cling thereto; a metering roller having a smooth liquid receptive surface; at least one of said metering or transfer roller having a resilient surface, said rollers being in indented surface pressure relationship; means to drive the transfer roller at a velocity different from that of the web; and means to supply liquid at the contacting surfaces of the metering roller and transfer roller.

40. In a device for applying liquid to liquid receptive material, a first roller having a continuous, uninterrupted, hard, polished, hydrophilic surface thereon; a second roller having a smooth resilient, surface thereon in rotative contact with the surface of the first roller, and adapted to be indented in metering relationship with the first roller; means to supply liquid at the contacting surfaces of the first and second rollers; means to vary the surface pressure relationship of the first and second rollers to control the thickness of a film of liquid metered therebetween; and means in indented surface contact with at least one of the rollers to rotate the metered film into contact with the liquid receptive material.

41. In a device for applying liquid to a moving web of material having a liquid receptive surface thereon, a liquid carrying transfer roller having a uniform smooth continuous surface running in pressure contact with one surface of the web, said surface on the roller being passive to chemical reaction with the liquid carried thereon; a metering roller having a smooth liquid receptive surface running in pressure contact with the surface of the transfer roller, the metering roller and the transfer roller being arranged to meter a film of aqueous liquid; at least one of said metering or transfer roller having a smooth resilient surface, whereby they are in indented surface pressure relationship; means to vary the surface speed relationship between the metering roller and the transfer roller; means to vary the relative surface speeds of the transfer roller and the web; and means to supply liquid at the contacting surfaces of the metering roller and transfer roller.

42. In a device for metering and applying liquid having waterlike viscosities to a moving web of liquid receptive material, a liquid carrying transfer roller having a smooth continuous liquid receptive surface positioned in pressure relation with the web; a metering roller having a smooth continuous liquid receptive surface, at least one of said metering or transfer roller having a resilient surface; means for supporting said metering and transfer rollers in pressure indented relation for forming a continuous uninterrupted film of metered thickness on the surface of the transfer roller; means to rotate the transfer roller at a speed different from that of the web of liquid receptive material; means to rotate the metering roller such that contacting surfaces between the metering roller and transfer roller move in the same direction; and means to supply liquid at contacting surfaces of the metering and transfer rollers.

43. In a device for metering and applying liquid having waterlike viscosities to a web of liquid receptive material, an applicator roller having a smooth surface in pressure relation with at least one surface of the web; a transfer roller having a smooth surface; a metering roller having a smooth surface, at least one of said rollers having a resilient surface; means supporting said applicator roller and transfer roller in pressure indented relation and supporting the metering roller in pressure indented relation with the transfer roller, said rollers being arranged to meter a continuous, uninterrupted film of liquid; means to rotate the rollers; means to supply liquid at the contacting surfaces of the metering and transfer rollers; and means to vary the surface speed of the transfer roller relative to that of the applicator roller.

44. A method of controlling the addition of moisture to liquid absorptive material comprising the steps of: metering a thin film of fluid having low viscosity between a transfer roller and a metering roller, said rollers having smooth surfaces in pressure indented relationship, the surface of at least one of said rollers having hydrophilic properties; rotating the metered film of fluid in contact with the absorptive member; and controlling the pressure between the metered film and the absorptive member to control the rate at which fluid is accepted by the absorptive member.

45. The method called for in claim 44 with the addition of the step of regulating the time which the absorbent member is in contact with the metered film of fluid to control the quantity of fluid absorbed.

46. The method called for in claim 44 with the addition of the step of controlling the pressure between the metering roller and the transfer roller along the length of said rollers.