Abstract:
Apparatus for applying coating liquid to a web of paper traveling over a web supporting surface at speeds of 3,000 or more feet per minute to produce a coated web free of streaking and other imperfections includes the structural elements for distributing coating liquid onto the supported web through a limited application zone within a short dwell time of the liquid on the web, the web moving through the application zone at a speed that is sufficiently high to create turbulence in the coating liquid being applied to the web, doctoring the coating liquid on the web by biasing a primary doctor against the coated web at the rear edge of the application zone so as to form a layer of coating liquid on the web as the web leaves the application zone, the turbulence in the coating liquid causing machine direction streaks in the layer of the coating liquid as the web leaves the application zone; and, at a location downstream and isolated from the application zone, performing a successive doctoring of excess coating liquid on the supported web by biasing a final doctor blade against the coated web to remove excess coating from the web and to level and smooth the coating retained on the web to a final wet film thickness and smoothness.
Abstract:
A web coater is provided with a doctor blade having an active edge or tip engaging the web at a predetermined position. The force applied by such active edge is adjusted by movement of jaws gripping the opposite edge of the blade. The jaws are moved along a curve empirically established to maintain the active edge of the blade in a predetermined fixed position during the adjustment. The angle of incidence of the active edge of the blade relative to the web is also maintained constant by pivoting a blade supporting frame about an axis coincident with the active edge. A controller is supplied with empirically established data developed by utilizing test blades to establish polynomial formulas having constants corresponding to each of the various blades intended to be used by the coater. The controller also automatically compensates for blade wear.
Abstract:
A heat-sensitive recording material produced by a process wherein an excess amount of a color developing layer coating solution or a protective layer coating solution is removed by a roll blade coater is excellent in recording machine applicability and dynamic sensitivity without bringing about streaks, pressure fogging and heat fogging on the uppermost treated surface.
Abstract:
A squeegee device applies material to a web substrate, which is guided across or held in contact with an abutment. The support body of the sequeegee contains a magnetic device extending along its longitudinal direction that holds a squeegee element made of magnetizable material. The squeegee edge is held against the substrate by the force of a magnetic device in the support body of the squeegee and a magnetic device under the abutment. In an alternative embodiment, no magnetic device is located under the abutment. However the abutment is made of ferrous metal to attract the magnetic device, causing pressure between the substrate and squeegee.
Abstract:
The doctor device has a profile member pivotally mounted to a retaining member that is carried on a mount. Vertical movement of the mount causes angular displacement of the profile member thereby changing the material application area disposed adjacent and upstream of the doctor. The doctor is either a doctor blade or roll doctor. In the case of a roll doctor, a receptacle is formed in the profile member and the roll doctor is magnetically retained within the receptacle. During application of a material to an application surface with the roll doctor, the roll doctor is magnetically attracted to the application surface by a second magnetic device located beneath the application surface or work surface.
Abstract:
Apparatus for coating paper webs having a doctor blade held in a clamping device which is mounted in a moveable holder. The clamping device is mounted to be pivotable about an axis parallel to the pivot axis of the holder and at a distance from the end of the doctor blade which is greater than the distance from the end of the clamping device.
Abstract:
An apparatus for the continuous simultaneous application of coatings of constant thickness to two sides of a material web, having two adjustable two-edged spreader blades confronting one another at an angle, between which the material web passes for the proportioning of the coatings, a chuck for each blade, and means clamping each spreader blade along one edge in the chuck, the other edge of each blade parallel to the clamping line being free and engaging under bias and a corresponding biasing force the material web carried over the free edge of the other spreader blade at an acute angle to the direction of movement of the material web, and means applying a biasing force to each blade along a fulcrum line the improvement wherein one spreader blade is rigid and the other spreader blade is resilient, the chuck of the resilient spreader blade being pivotable about the engagement line between the resilient spreader blade and the rigid spreader blade and about a line outside of the clamping line for movement away from the rigid blade the clamping line of the resilient spreader blade being displaceable relative to the rigid spreader blade to adjust the biasing force while the engagement line and the fulcrum line of the resilient spreader blade are fixed relative to the rigid spreader blade during a continuous coating operation.
Abstract:
A device for continuous application of coating of constant thickness to a web employing an elastic coating knife fixed in a clamping jaw and having a free edge parallel with a fixing line, the knife being prestressed against the web which is running over a roll, the knife center area being supported along a backup line, the clamping jaw being pivotable about the abutting line of the knife on the roll and about a line outside the fixing line in which the abutting and backup lines are fixed relative to the roll and the fixing line is continuously movable relative to the roll.
Abstract:
A method and apparatus for coating at least one face of a moving web, such as a paper web, in which the web is fed longitudinally at a speed in excess of 400 meters per minute between a movable support and a blade forming, with the movable support, a nip. The blade has a bevel at the point of contact with the web, and an excess of coating material is applied at one side of the web in the nip, the coating material having a dryness content exceeding 60% and/or a viscosity exceeding 1500 cp. The angle of the blade is controlled so that it extends at most 20.degree. to the web and the bevel width, as measured in the direction of movement of the web, is at most 0.05 centimeters. Preferably, the blades are urged against the web with a force not exceeding 2 kgf per centimeter width of web.
Abstract:
A method for simultaneously coating the opposite sides of a paper web which involves employing an opposed blade coating system. Wet coating material is applied to the opposite sides of the web, the wet coated web is passed through the nip of a flexible blade unit comprised of a pair of blades having flat bevelled working surfaces engaging opposite sides of the coated web in opposed relationship with each other for metering the layer of coating on the opposite sides of the web, and thereafter the coated web is dried.