US2357824A - Apparatus for coating paper - Google Patents

Description

WEQZ, 1944. 5. HAYWOOD 2,357,824

APPARATUS FOR COATING PAPER FiledApril 26, 1940 22 lNVENTOR 652 440 HAYWOOD ATTORN Patented Sept. 12, 1944 APPARATUS FOR COATING PAPER Gerald Haywood, Westernport, Md., assignor to West Virginia Pulp and Paper Company, New York, N. -Y., a corporation of Delaware Application April 26, 1940, Serial No. 331,691

4 Claims.

My present invention relates to improved apparatus for coating paper and the like.

It has been proposed to apply coating compositions to paper by using a roll having a multitude of liquid receiving indentations in its surface whereby to deliver to the paper web a more or less measured amount of such composition or color. In the type of coating apparatus to which the present invention relates, a transfer roll has been used to carry the color delivered by the liquid receiving indentations to the web. The use of a transfer roll in this manner is of advantage inasmuch as it permits the droplets of color deposited by the indented roll the better to coalesce and form a film for application to the web. However, it frequently happens that this effect is not always obtained; sometimes the design of the indented roll is printed on the web, while other times the coating applied is uneven because of the inability to control the character'of the surface of the transfer roll prior to its contact with the indented roll.

The object of my present invention is, therefore, to-provide an improved .coating device which will not only overcome the above mentioned disadvantages, but-will have various advantages not possible of realization by the prior art device above described. In carrying out the invention in its preferred form I provide an endless belt which receives a measured quantity of color and transports same to the paper web so as to afford a much greater opportunity for the color to form into a film during the time of transport upon the belt. A further object is to provide an improved arrangement of the belt per se which will facilitate the steady adjustment of the same and permit, moreover, various operations such as cleaning, pre-wetting, etc., to be performed upon it. A

still further object is to so mount the belt with respect to the paper web as to provide a clearance between the belt and the web which canbe varied and whichin addition will permit of the separation of the belt from the web should an ob- Fig. 3 is a similar view showing the contact of the apron with the paper to be coated. In Fig. 1 the web of paper l to be coated passes over the backing roll II which may be one of a series of drier cylinders, others of which being denoted by l2 and I3. Disposed away from I cylinder II, for example, on the floor level below,

is indented roll it which is supplied with color by means of fountain roll Ila in a pan H in which is provided a supply of color l8. Roll Ila may be driven in the same direction as roll IE but at a 1 less speed than said l, nd paced therefrom depth from .001 to .006 inch. Desirably a doctor I9 is provided to limit the amount of color carried by the roll substantially to that contained in the indentations, although under-certain circumstances the doctor may be omitted. In contact with the surface of roll it is endless belt or apron 20, desirably of rubberized fabric of known type having a uniform surface which passes preferably over a plurality of guide pulleys 21, 22, 23, 24, 25, one of which, 24, is displaced laterally of two of the others, i. e., rolls 23 and 25. By this means the belt 20 may be adjusted in tension without altering the distance between pulleys 2| and 22. To this end roll 24 preferably is mounted in a journal block 26 which is slidably disposed upon a support 21. By means of a weight 28, cable 29, pulley 30, the block 26 may be urged to the left, thereby placing the belt under the desired tension. The pulley 22 is preferably mounted upon a lever 3i having suspended from its end a Weight 33 and having its pivot at 32 deriving its support from the ground through member 3211 only a portion of which is shown. an adjustable stop 34 mounted on a support 35 the position of the pulley 22 and the contacting surface of the belt 20 may be accurately adjusted, with reference to the web l0. At the same time the arrangement will permit of the pulley 22 yielding against the force of the weight 33 acting through the lever 3|, in case an obstruction should lodge in the nip between thebelt 20 and the web 10. Driving gears are indicated in the drawing for the cylinders ll, l2, l3 and for rolls 22, 2|

and I6, it being desirable that the speed of travel of the Web Ill be equal to that of apron 20.

By means of The arrangement of the belt 20 as shown also permits various operations to be performed upon it; thus, pulley 23 may also constitute a cleaning roll having a doctor 31 upon which is sprayed water from a perforated pipe 38. When the belt passes around pulley 24 it may also be given a further cleaning by means of a brush roll 39. After passing beneath the pulley 24 the belt may be moistened by means of a further spray,

40 so as to be wet when the roll I6 is reached. Very often the-wire side of the web I will yield a certain amount of fuzz to the apron 20, which if allowed to accumulate would interfere with the coating operation. However, by means of the spray 38 and the cleaning roll 39 any such accumulation can be effectively prevented. Furthermore, by having the surface of the apron wet when it receives its coating from the indented roll IS, the formation of a smooth film on the apron is facilitated. (Frequently when coating unsized paper by using a transfer roll instead of an apron the roll becomes dry after contact with the web and thereafter acquires and transfers an uneven film of color because of this dry condition.)

It will be noted that the use of a belt in the manner described has a further advantage over a roll for the same purpose in that the roll is at all times subjected to the action of centrifugal n force, which may tend to prevent coalescence of the particles, whereas in the case of a belt a straight line travel is provided in which centrifugal force is not acting. Furthermore, by the provision of the travelling belt described it is possible to install coating equipment upon a Fourdrinier machine with a minimum of modi-' which would not be available on the machine floor level. It will also be noted that the large area of the apron, which is at all times covered with a film of color, permits operation: to be performed upon the film as may be desired, such as drying, treatment with chemical reagents, etc.

Any coating colors may be employed that would be suitable with the arrangement without uzing an offset roll instead of a travelling band. In addition, other colors may be used which would be usable with the offset roll only with difficulty due to the greater oportunity afforded by the travel of the band for the deposited color to form a film.

My improved device may be used for coating paper during its manufacture on the Fourdrinier machine or as a separate operation after the paper has left the machine and has been reeled. Furthermore, when coating paper on the Fourdrinier the coating may be applied either at a point where the web contains a substantial quantity of moisture, as for example, immediately following the press rolls, or after the paper is entirely dry, 1. e., containing under 10% moisture. Various other changes may be made in the specific embodiment shown.

I claim:

1. In a device for coating paper with a uniform coating of color, means for feeding a continuous web of said paper, a roll having in its surface a multitude of uniformly disposed liquid receiving indentations, said roll being separated from said web, means for supplying said roll with color whereby to fill the indentations therein and enable same to deliver a measured amount thereof. and an endless travelling band having a uniform surface disposed in rolling contact with said roll to receive color carried thereby and to transport the same to said web and there to transfer said color as a film thereto.

2. In a device for coating paper with a uniform coating of color, means for feeding a continuous web of said paper, an endless travelling band having rolling contact with said web, means for continuously applying a uniform amount of color to a region of said band remote from said web so as to enable said band to transfer the applied color to said web at such region ofv contact, a backing cylinder for said web at such region of contact, a pulley around which said band-travels at such region of contact, 'means for adjusting the position of said roll toward and away from said web, including means for permitting said pulley to' separate from said web in case of an obstruction passing between-said band and said web, and means for maintaining said band under tension.

3. In a device for coating paper with a uniform coating of color, means for feeding a continuous web' of said paper, a roll having in its surface a multitude of uniformly dispoied liquid receiving indentations, said roll being separated from said web, means for supplying said roll with color whereby to fill the indentations therein and enable same to deliver a measured amount thereof, and an endless travelling band diiposed in rolling contact with said roll to receive color carried thereby and to transport the same to said web and. there to transfer said color as a film thereto, and means for wetting the said band prior to the point at which it receives its charge of color.

4. In a device for coating paper with a uniform coating of color, means for feeding a continuous web of said paper, an endless travelling band having rolling contact with said web, means for continuously applying a uniform amount of color to a region of said band remote from said web so as to enable said band to transfer the applied color to said web at such region of contact, a tensioning roll for said band, means for cleaning said band after it has discharged its color to the web, and means for pre-wettin8 same prior to the point at which it receives its charge of color.

- GERALD HAYWOOD.

Images