Pre-coating device for surface protection paper coating of gypsum board

Abstract

The invention provides a pre-coating device for a gypsum board surface protection paper coating, which comprises a discharging unit and a coating roller unit arranged at the downstream of the discharging unit, and reinforcing coatings are formed on the inner surfaces of upper surface protection paper and lower surface protection paper in a coating and rolling manner; the first steering roller assembly is arranged at the downstream of the coating rolling assembly and is used for adjusting the inner surface of the upper surface protection paper from an upward state to a downward state; the visual monitoring assembly is used for shooting transmission images of the upper surface protecting paper and the lower surface protecting paper before coating; the deviation rectifying mechanism is arranged on the upstream of the coating rolling assembly, and the upper surface protecting paper and the lower surface protecting paper sequentially pass through the two deviation rectifying guide rollers respectively during conveying; the visual monitoring assembly and the deviation rectifying mechanism are connected with a processing system, the processing system obtains the offset of the upper surface protecting paper and the lower surface protecting paper before coating based on the monitoring result of the visual monitoring assembly, and the processing system regulates and controls the deviation rectifying mechanism to work; according to the invention, the upper surface protection paper and the lower surface protection paper can be firmly bonded, and the strength of the gypsum board is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of gypsum boards, and particularly to a pre-coating device for a coating on the facing paper of a gypsum board. Background Art

[0002] In the production process of traditional facing paper gypsum boards, the formed gypsum slurry is usually laid on the lower facing paper, and the upper facing paper is pressed to adhere to the formed gypsum slurry, and only relies on the viscosity of the formed gypsum slurry to achieve the bonding work between the lower facing paper and the upper facing paper.

[0003] Since only relying on the viscosity of the formed gypsum slurry to achieve the bonding work of the facing paper, the bonding of the upper paper and the lower paper in the production of gypsum boards is unstable, and it is easy to peel off the paper, resulting in low strength of various gypsum boards.

[0004] Moreover, to ensure that the distribution state of the coating formed on the inner surfaces of the upper facing paper and the lower facing paper always remains stable, and to always symmetrically lay the coated gypsum slurry flat on the facing paper, a deviation correction station needs to be set upstream of the coating roller pressing station for the upper facing paper and the coating roller pressing station for the lower facing paper. In the existing deviation correction operations, since most of them first adjust the inclined-transported facing paper to be straight, and then adjust the corrected facing paper to be reset, it takes a long time and there is still an easy problem of offset in the laying of the coated gypsum slurry. Summary of the Invention

[0005] The purpose of the present invention is to provide a pre-coating device for a coating on the facing paper of a gypsum board, so as to solve the technical problems in the prior art that the bonding of the upper paper and the lower paper in the production of gypsum boards is unstable, it is easy to peel off the paper, resulting in low strength of various gypsum boards, and there is an easy problem of offset in the laying of the coated gypsum slurry.

[0006] To solve the above technical problems, the present invention specifically provides the following technical solutions: A pre-coating device for a coating on the facing paper of a gypsum board, comprising: A coating roller pressing assembly, including a discharging unit and a coating roller unit arranged downstream of the discharging unit, and forming a reinforcing coating on the inner surfaces of the upper facing paper and the lower facing paper by means of coating and roller pressing; A first turning roller wheel assembly, arranged downstream of the coating roller pressing assembly, and used for adjusting the inner surface of the upper facing paper from an upward state to a downward state; A visual monitoring assembly, respectively installed above the inner surface of the upper facing paper in an upward state and above the inner surface of the lower facing paper, and used for taking transmission images of the upper facing paper and the lower facing paper before coating; A deviation correction mechanism, arranged upstream of the coating roller pressing assembly, the deviation correction mechanism includes two deviation correction guide rollers, and when the upper facing paper and the lower facing paper are being transported, they respectively pass through the two deviation correction guide rollers in sequence; The visual monitoring component and the rectifying mechanism are connected to a processing system. The processing system obtains the offset of the upper facing paper and the lower facing paper before coating based on the monitoring result of the visual monitoring component, and the processing system controls the operation of the rectifying mechanism based on the offset.

[0007] As a preferred embodiment of the present invention, when the processing system processes the monitoring result of the visual monitoring component, the specific modules used include: An image processing module, which is used to perform image processing on the transmitted images of the upper facing paper and the lower facing paper captured by the visual monitoring component, so as to be able to identify the straight lines where the two side edges of the upper facing paper and the lower facing paper are located, and intercept the transmitted images, and retain the clear images of the two side edges of the upper facing paper and the lower facing paper as the analysis objects; A real-time coordinate system construction module, which is used to construct a real-time two-dimensional coordinate system with the center position of the width of the facing paper of the analysis object as the origin; An offset calculation module, which selects endpoint reference points from the straight lines of the two side edges of the upper facing paper and the lower facing paper based on the real-time coordinate system construction module, determines the offset direction of the facing paper based on the coordinates of the endpoint reference points, and determines the offset of the facing paper based on the coordinates of the reference points on the two side edges; A standard coordinate system construction module, which takes the transmitted image when the facing paper has no offset as the reference image, constructs a standard two-dimensional coordinate system with the center position of the width of the facing paper of the reference image as the origin, selects feature points from the reference image, and determines the standard coordinate values of the feature points in the standard two-dimensional coordinate system; A rectifying control module, based on the determined offset direction and offset of the facing paper, controls the two rectifying guide rollers of the rectifying mechanism to work synchronously and in opposite directions, and the controlled offset of the two rectifying guide rollers of the rectifying mechanism is half of the offset; And reconstructs the standard two-dimensional coordinate system in the transmitted image after rectification based on the standard coordinate values of the feature points, determines the reference offset based on the X coordinate value of the origin of the two-dimensional coordinate system in the standard two-dimensional coordinate system, controls the two rectifying guide rollers of the rectifying mechanism to work synchronously and in the same direction, and the controlled offset of the two rectifying guide rollers of the rectifying mechanism is the reference offset.

[0008] As a preferred embodiment of the present invention, the standard coordinate system construction module constructs a standard two-dimensional coordinate system with the center points of the upper facing paper and the lower facing paper in the non-offset state, and the real-time coordinate system construction module constructs a real-time two-dimensional coordinate system with the center points of the upper facing paper and the lower facing paper monitored in real time; The offset calculation module determines the inclination angle of the straight line where the side edge of the upper facing paper or the lower facing paper is located based on the real-time two-dimensional coordinate system, and calculates the diagonal transmission offset of the upper facing paper or the lower facing paper in combination with the endpoint coordinate values of the upper facing paper or the lower facing paper; The offset calculation module calculates the central offset of the upper facing paper or the lower facing paper relative to the standard position respectively based on the difference in the abscissa between the standard two-dimensional coordinate system and the real-time two-dimensional coordinate system.

[0009] As a preferred solution of the present invention, the deviation rectification control module controls the two deviation rectification stations to perform synchronous reverse deviation rectification on the upper facing paper or synchronous reverse deviation rectification on the lower facing paper based on the oblique transmission offset, until the upper facing paper or the lower facing paper is corrected to be transmitted in a collinear direction; The deviation rectification control module compares the origin coordinate values of the real-time two-dimensional coordinate systems of the deviation-rectified upper facing paper and lower facing paper with the standard two-dimensional coordinate system, and controls the two deviation rectification stations of the upper facing paper and the lower facing paper to perform synchronous co-directional deviation rectification according to the comparison result, so that the upper facing paper or the lower facing paper is corrected to be transmitted collinearly along the standard point position.

[0010] As a preferred solution of the present invention, the real-time coordinate system construction module constructs a real-time two-dimensional coordinate system with the center point of the upper facing paper captured in real time, and the implementation method of constructing a real-time two-dimensional coordinate system with the center point of the lower facing paper captured in real time is the same, specifically: Perform image processing on the transmission images of the upper facing paper and the lower facing paper during the transmission process respectively, so as to be able to identify the straight lines where the two side edges of the upper facing paper are located, and the straight lines where the two side edges of the lower facing paper are located; Take the area where the traces of the two side edges of the lower facing paper are obvious as the analysis object, and determine the central positions of the upper facing paper and the lower facing paper. Take the central positions of the upper facing paper and the lower facing paper as the origin, and construct a two-dimensional coordinate system respectively, where the X-axis is parallel to the width direction of the upper facing paper and the lower facing paper, and the Y-axis is perpendicular to and intersects with the X-axis.

[0011] As a preferred solution of the present invention, select multiple groups of symmetric reference points on the straight lines where the two side edges of the upper facing paper are located, and determine the coordinate values corresponding to the multiple groups of reference points on the straight lines where the two side edges of the upper facing paper are located; Based on the coordinate values corresponding to at least two reference points on the single side edge of the upper facing paper obtained in sequence, the offset calculation module determines the transmission offset direction of the upper facing paper; The offset calculation module calculates the coordinate values corresponding to the multiple groups of reference points on the two side edges of the upper facing paper, and calculates the difference in the X coordinate values of the same group of reference points on the two side edges of the upper facing paper, so as to calculate the transmission offset of the upper facing paper; Select multiple groups of symmetric reference points on the straight lines where the two side edges of the lower facing paper are located, and determine the coordinate values corresponding to the multiple groups of reference points on the straight lines where the two side edges of the lower facing paper are located; Based on the coordinate values respectively corresponding to at least two control points on one side of the lower facing paper obtained in sequence, determine the transmission offset direction of the lower facing paper; The offset calculation module calculates the coordinate values respectively corresponding to multiple groups of control points on both sides of the lower facing paper, and calculates the difference in the X coordinate values of the same group of control points on both sides of the lower facing paper, so as to calculate the transmission offset amount of the lower facing paper.

[0012] As a preferred solution of the present invention, the coordinate values x1, x2,... respectively corresponding to at least two control points are sequentially obtained along a straight line on one side of the upper facing paper or the lower facing paper, and x1 - x2 is calculated; If (x1 - x2) > 0, then the transmission offset direction of the upper facing paper or the lower facing paper is the positive direction, If (x1 - x2) < 0, then the transmission offset direction of the upper facing paper or the lower facing paper is the negative direction; If (x1 - x2) = 0, then there is no transmission offset for the upper facing paper or the lower facing paper; Among them, when (x1 - x2) = 0, the upper facing paper or the lower facing paper at this time is expressed as having no transmission offset, and the standard coordinate system construction module constructs a two-dimensional coordinate system for the transmission image of the upper facing paper or the lower facing paper at this time, and uses this two-dimensional coordinate system as the standard two-dimensional coordinate system corresponding to the upper facing paper and the lower facing paper without offset; Select an object with a constant position from the transmission image of the upper facing paper or the lower facing paper as a feature point, and determine the two-dimensional coordinate values of the feature point in the standard two-dimensional coordinate system.

[0013] As a preferred solution of the present invention, the offset calculation module respectively determines the X coordinate values x1a, x1b, x2a, x2b of the upper and lower two groups of endpoints on both sides of the lower facing paper or the upper facing paper; The calculation formula for the transmission offset amount is: .

[0014] As a preferred solution of the present invention, according to the inclination of the straight line where one side of the upper facing paper or the lower facing paper is located in the two-dimensional coordinate system, obtain the value of x1 - x2. When (x1 - x2) ≠ 0, according to the transmission offset amount of the upper facing paper or the lower facing paper, use two rectifying stations to perform synchronous reverse rectification on the upper facing paper or synchronous reverse rectification on the lower facing paper; Among them, when (x1 - x2) > 0, the rectification control module controls the rectification direction of the rectifying station in the upstream for the upper facing paper or the lower facing paper to be the negative direction of the X axis, and the specific rectification amount is 1 / 2Py. The rectification direction of the rectifying station in the downstream for the upper facing paper or the lower facing paper is the positive direction of the X axis, and the specific rectification amount is 1 / 2Py; When (x1 - x2) < 0, the deviation correction control module controls the deviation correction direction of the upstream deviation correction station for the upper facing paper or the lower facing paper to be the positive direction of the X-axis, and the specific deviation correction amount is 1 / 2Py. The deviation correction direction of the downstream deviation correction station for the upper facing paper or the lower facing paper is the negative direction of the X-axis, and the specific deviation correction amount is 1 / 2Py.

[0015] As a preferred embodiment of the present invention, after the deviation correction control module uses two deviation correction stations to perform synchronous reverse deviation correction on the upper facing paper or synchronous reverse deviation correction on the lower facing paper, a standard two-dimensional coordinate system is reconstructed and restored from the transmission image of the corrected upper facing paper or the lower facing paper, and the standard coordinate value of the origin of the two-dimensional coordinate system in the standard two-dimensional coordinate system is determined. Based on the X coordinate value of the standard coordinate value, the two deviation correction stations are controlled to perform synchronous forward deviation correction to restore to the standard two-dimensional coordinate system: Find the corresponding feature points from the transmission image of the upper facing paper or the lower facing paper, and based on the standard two-dimensional coordinate values of all feature points, reconstruct and restore the standard two-dimensional coordinate system on the transmission image; Determine the X coordinate value x0 of the origin of the two-dimensional coordinate system in the standard two-dimensional coordinate system; Among them, when the X coordinate value x0 > 0, the deviation correction control module controls the deviation correction direction of the two deviation correction stations for the upper facing paper or the lower facing paper to be the negative direction of the X-axis, and the specific deviation correction amount is ; When the X coordinate value x0 < 0, the deviation correction control module controls the deviation correction direction of the two deviation correction stations for the upper facing paper or the lower facing paper to be the positive direction of the X-axis, and the specific deviation correction amount is ; When the X coordinate value x0 = 0, the deviation correction control module does not control the two deviation correction stations to work.

[0016] The present invention has the following beneficial effects compared with the prior art: The present invention utilizes the adhesion between the reinforcement coating and the formed gypsum slurry to ensure that both the upper facing paper and the lower facing paper are firmly bonded, thereby improving the strength of the gypsum board; When the present invention actively adjusts the reset of the upper facing paper and the lower facing paper, the deviation correction components of the two deviation correction stations are used to perform synchronous two-way deviation correction, so that the facing paper after the first deviation correction is as close as possible to the standard position, reducing the deviation correction operation duration, and also reducing the operation duration of the secondary deviation correction of the facing paper after the first deviation correction, effectively avoiding the subsequent offset of the reinforcement coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only exemplary. For those of ordinary skill in the art, without creative efforts, other implementation drawings can also be obtained based on the provided drawings.

[0018] Figure 1 Structural schematic diagram of the pre - coating device according to an embodiment of the present invention; Figure 2 Structural schematic diagram of the coating roll - pressing assembly according to an embodiment of the present invention; Figure 3 Structural block diagram of the control system according to an embodiment of the present invention; Figure 4 Structural block diagram of the regulation system of the coating roll - pressing assembly according to an embodiment of the present invention; Figure 5 Diagram of the deviation correction amount of the traditional deviation correction implementation method according to an embodiment of the present invention; Figure 6 Diagram of the deviation correction amount of the deviation correction implementation method according to an embodiment of the present invention; The reference numerals in the figure respectively represent the following: 1 - coating roll - pressing assembly; 2 - first turning roller assembly; 3 - visual monitoring assembly; 4 - deviation correction mechanism; 5 - processing system; 101 - discharging unit; 102 - coating roller unit; 51 - image processing module; 52 - real - time coordinate system construction module; 53 - offset calculation module; 54 - standard coordinate system construction module; 55 - deviation correction regulation module. Specific embodiments

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0020] As Figure 1 shown, the present invention also provides a pre - coating device for the coating of the gypsum board facing paper. As Figure 1 and Figure 2 shown, it includes a coating roll - pressing assembly 1, a first turning roller assembly 2, a visual monitoring assembly 3, and a deviation correction mechanism 4.

[0021] The coating roller pressing assembly 1 includes a discharging unit 101 and a coating roller unit 102 arranged downstream of the discharging unit 101, and a reinforcing coating is formed on the inner surfaces of the upper facing paper and the lower facing paper by means of coating and roller pressing.

[0022] Specifically, two coating roller pressing assemblies 1 are provided, which are respectively arranged at the inner surface positions of the upper facing paper and the lower facing paper.

[0023] Among them, each coating roller pressing assembly 1 is divided into an upper facing paper coating mechanism and a lower facing paper coating mechanism. Both the upper facing paper coating mechanism and the lower facing paper coating mechanism include a discharging unit 101 and a coating roller unit 102 arranged downstream of the discharging unit 101. The discharging unit 101 is used to output high-density gypsum slurry at the center position of the lower surface of the upper facing paper and the lower surface of the upper facing paper. The coating roller unit 102 is used to extrude and lay the high-density gypsum slurry and form a thin coating on the lower surface of the upper facing paper and the lower surface of the upper facing paper.

[0024] In the production process of traditional facing paper gypsum boards, the formed gypsum slurry is usually laid on the lower facing paper, and the upper facing paper is extruded and bonded to the formed gypsum slurry, and only the viscosity of the formed gypsum slurry is relied on to realize the bonding work between the lower facing paper and the upper facing paper.

[0025] In this embodiment, before the formed gypsum slurry is laid, a high-density gypsum slurry is coated on the lower surface of the upper facing paper through the upper facing paper coating mechanism, and a high-density gypsum slurry is coated on the upper surface of the lower facing paper through the lower facing paper coating mechanism, and a thin coating is formed on the lower surface of the upper facing paper and the lower surface of the upper facing paper. The adhesive force between the thin coating and the formed gypsum slurry is used to ensure that both the upper facing paper and the lower facing paper can be firmly bonded, improving the strength of the gypsum board.

[0026] In order to realize the extrusion and laying of the high-density gypsum slurry to form a thin coating on the lower surface of the upper facing paper and the lower surface of the upper facing paper, the coating roller unit 102 of the upper facing paper coating mechanism includes a first extrusion roller and a second extrusion roller arranged on the upper and lower sides of the upper facing paper.

[0027] The coating roller unit 102 of the lower facing paper coating mechanism includes a third extrusion roller arranged above the lower facing paper.

[0028] In order to leave blank areas on both sides of the upper facing paper and the lower facing paper to facilitate the later folding work, the length of the second extrusion roller is less than the width of the upper facing paper, and the length of the third extrusion roller is less than the width of the lower facing paper.

[0029] The first turning roller assembly 2 is arranged downstream of the coating roller pressing assembly 1 and is used to adjust the inner surface of the upper facing paper from an upward state to a downward state. Among them, in order to perform the coating work on the inner surface of the upper facing paper, it is necessary to first transport the inner surface of the upper facing paper upward, and after passing through the first turning roller assembly 2, it becomes downward transport, so as to facilitate laying on the raw gypsum pulp to form a wet gypsum board.

[0030] The visual monitoring assemblies 3 are respectively installed above the inner surface of the upper facing paper in the upward state and above the inner surface of the lower facing paper, and are used to capture the transmission images of the upper facing paper and the lower facing paper before coating.

[0031] There are two visual monitoring assemblies 3, which are respectively on the transmission line of the upper facing paper and on the transmission line of the lower facing paper, and are specifically installed upstream of the coating roller pressing assembly 1.

[0032] The deviation rectifying mechanism 4 is arranged upstream of the coating roller pressing assembly 1. The deviation rectifying mechanism 4 includes two deviation rectifying guide rollers. When the upper facing paper and the lower facing paper are transmitted, they respectively pass through the two deviation rectifying guide rollers in sequence. Similarly, there are also two deviation rectifying mechanisms 4, which are respectively on the transmission line of the upper facing paper and on the transmission line of the lower facing paper.

[0033] The visual monitoring assembly 3 and the deviation rectifying mechanism 4 are connected to a processing system 5. The processing system 5 obtains the offset amounts of the upper facing paper and the lower facing paper before coating based on the monitoring results of the visual monitoring assembly 3, and the processing system 5 controls the operation of the deviation rectifying mechanism 4 based on the offset amounts.

[0034] As Figure 3 and Figure 4 shown, when the processing system 5 processes the monitoring results of the visual monitoring assembly 3, the specific modules used include: an image processing module 51, a real-time coordinate system construction module 52, an offset calculation module 53, a standard coordinate system construction module 54, and a deviation rectifying control module 55.

[0035] The image processing module 51 is used to perform image processing on the transmission images of the upper facing paper and the lower facing paper captured by the visual monitoring assembly 3, so as to be able to identify the straight lines where the two side edges of the upper facing paper and the lower facing paper are located, and intercept the transmission images, and retain the clear images of the two side edges of the upper facing paper and the lower facing paper as the analysis objects; The real-time coordinate system construction module 52 is used to construct a two-dimensional coordinate system with the center position of the width of the facing paper of the analysis object as the origin; The offset calculation module 53 selects multiple groups of reference points on the straight lines of the two side edges of the upper facing paper and the lower facing paper based on the real-time coordinate system construction module 52, determines the offset direction of the facing paper based on the coordinates of at least two reference points on a single side edge, and determines the offset amount of the facing paper based on the coordinates of the reference points on the two side edges; The standard coordinate system construction module 54 uses the transmission image when the facing paper has no offset as the reference image, takes the center position of the width of the facing paper in the reference image as the origin, constructs a standard two-dimensional coordinate system, selects feature points from the reference image, and determines the standard coordinate values of the feature points in the standard two-dimensional coordinate system; The deviation correction control module 55 controls the two deviation correction guide rollers of the deviation correction mechanism 4 to work synchronously and in opposite directions based on the determined deviation direction and deviation amount of the facing paper, and the controlled deviation amount of the two deviation correction guide rollers of the deviation correction mechanism 4 is half of the deviation amount; And based on the standard coordinate values of the feature points, reconstruct the standard two-dimensional coordinate system in the transmitted image after deviation correction, determine the reference deviation amount based on the X coordinate value of the origin of the two-dimensional coordinate system in the standard two-dimensional coordinate system, control the two deviation correction guide rollers of the deviation correction mechanism 4 to work synchronously and in the same direction, and the controlled deviation amount of the two deviation correction guide rollers of the deviation correction mechanism 4 is the reference deviation amount.

[0036] In addition, in this embodiment, before the coating roller pressing assembly 1, the transmission deviation direction and transmission deviation amount of the upper facing paper and the lower facing paper are monitored in real time, and the upper facing paper and the lower facing paper are actively adjusted to be reset, so that the central positions of the coating roller units 102 of the upper facing paper coating mechanism and the lower facing paper coating mechanism, the central positions of the discharging units 101, and the central axis of the facing paper are always in the same plane, so as to ensure that the reinforcing coating formed on the inner surface of the lower facing paper is symmetrically distributed about the central axis of the lower facing paper, the widths of the blank areas left on both sides of the lower facing paper are the same, the reinforcing coating formed on the inner surface of the upper facing paper is symmetrically distributed about the central axis of the upper facing paper, and the widths of the blank areas left on both sides of the upper facing paper are the same. Therefore, the adhesive forces between the upper facing paper and the lower facing paper and the formed gypsum slurry are evenly dispersed, ensuring that the upper facing paper and the lower facing paper will not bulge.

[0037] Among them, when actively adjusting the upper facing paper and the lower facing paper to be reset, the deviation correction components of the two deviation correction stations are used for synchronous two-way deviation correction, so that the facing paper after the first deviation correction is as close as possible to the standard position, reducing the deviation correction operation time, and also reducing the operation time for the secondary deviation correction of the facing paper after the first deviation correction, effectively avoiding the subsequent deviation of the reinforcing coating.

[0038] If a single deviation correction station is driven to perform deviation correction work, then the deviation amount of the upper facing paper or the lower facing paper deviating from the original position will be greater, as Figure 5 shown, the deviation amount is a. Then, when the two deviation correction stations are subsequently driven to perform synchronous and same-direction deviation correction work and drive the upper facing paper or the lower facing paper to the original position, the overall deviation correction distance is relatively long at this time.

[0039] In order to improve the efficiency of the rectification work, the technical solution adopted in this embodiment is as follows: First, through visual monitoring, identify the transmission offset direction and offset amount of the upper facing paper and the lower facing paper, and then perform synchronous reverse rectification on the upper facing paper or synchronous reverse rectification on the lower facing paper at two rectification stations. As Figure 6 shown, the offset amount is b. Obviously, b is much smaller than a. Subsequently, drive the two rectification stations to perform synchronous forward rectification work. When driving the upper facing paper or the lower facing paper to the original position, the overall rectification distance is short at this time, so the regulation time is short, and rapid reset operation can be achieved.

[0040] In order to calculate the transmission offset direction and offset amount of the upper facing paper and the lower facing paper, the specific implementation method is as follows: First, construct a two-dimensional coordinate system. According to the straight lines where the two sides of the upper facing paper and the lower facing paper are located, combine the two-dimensional coordinate system to determine the offset direction and offset amount. Among them, the method of constructing a two-dimensional coordinate system with the center point of the upper facing paper is the same as that of constructing a two-dimensional coordinate system with the center point of the lower facing paper. Specifically: Perform image processing on the transmission images of the upper facing paper and the lower facing paper during transmission respectively, so as to be able to identify the straight lines where the two sides of the upper facing paper are located and the straight lines where the two sides of the lower facing paper are located; Take the area where the traces of the two sides of the lower facing paper are obvious as the analysis object, and determine the center positions of the upper facing paper and the lower facing paper. Take the center positions of the upper facing paper and the lower facing paper as the origin, and construct a two-dimensional coordinate system respectively. Among them, the X-axis is parallel to the width direction of the upper facing paper and the lower facing paper, the Y-axis is perpendicular to the X-axis direction orthogonally, and the intersection point is the origin position.

[0041] When calculating the transmission offset amounts of the upper facing paper and the lower facing paper respectively, determine the transmission offset direction and the specific offset amount respectively. The implementation method is as follows: (1) Select multiple groups of symmetric reference points on the straight lines where the two sides of the upper facing paper are located, and determine the coordinate values corresponding to the multiple groups of reference points on the straight lines where the two sides of the upper facing paper are located; Based on the coordinate values corresponding to at least two reference points on one side of the upper facing paper obtained in sequence, determine the transmission offset direction of the upper facing paper; (3) Calculate the coordinate values corresponding to the multiple groups of reference points on the two sides of the upper facing paper, and calculate the difference in the X coordinate values of the same group of reference points on the two sides of the upper facing paper to calculate the transmission offset amount of the upper facing paper; Similarly, the method for calculating the offset amount of the lower facing paper is the same as that of the upper facing paper: (1) Select multiple groups of symmetric reference points on the straight lines where the two sides of the lower facing paper are located, and determine the coordinate values corresponding to the multiple groups of reference points on the straight lines where the two sides of the lower facing paper are located; (2)Based on the coordinate values corresponding to at least two control points on one side edge of the lower wrapper paper obtained in sequence, determine the transmission offset direction of the lower wrapper paper; (3)Calculate the coordinate values corresponding to multiple groups of control points on both side edges of the lower wrapper paper, and calculate the difference in the X coordinate values of the same group of control points on both side edges of the lower wrapper paper to calculate the transmission offset amount of the lower wrapper paper.

[0042] Sequentially obtain the coordinate values x1, x2,... corresponding to at least two control points along a straight line on one side edge of the upper wrapper paper or the lower wrapper paper, and calculate x1 - x2; If (x1 - x2) > 0, then the transmission offset direction of the upper wrapper paper or the lower wrapper paper is the positive direction, If (x1 - x2) < 0, then the transmission offset direction of the upper wrapper paper or the lower wrapper paper is the negative direction; If (x1 - x2) = 0, then there is no transmission offset for the upper wrapper paper or the lower wrapper paper.

[0043] Among them, when (x1 - x2) = 0, the upper wrapper paper or the lower wrapper paper at this time is expressed as having no transmission offset. Construct a two-dimensional coordinate system for the transmission image of the upper wrapper paper or the lower wrapper paper at this time, and use this two-dimensional coordinate system as the standard two-dimensional coordinate system corresponding to when the upper wrapper paper and the lower wrapper paper have no offset; Select an object with a constant position from the transmission image of the upper wrapper paper or the lower wrapper paper as a feature point, and determine the two-dimensional coordinate values of the feature point in the standard two-dimensional coordinate system. Specifically, the feature points are distributed in the four quadrants of the standard two-dimensional coordinate system.

[0044] The implementation method for calculating the transmission offset amount of the upper wrapper paper or the lower wrapper paper is as follows: Respectively determine the X coordinate values x1a, x1b, x2a, x2b of the upper and lower two sets of end points on both side edges of the lower wrapper paper or the upper wrapper paper; The calculation formula for the transmission offset amount is: .

[0045] As an innovation point of this implementation method, in step 300, according to the inclination of the straight line where one side edge of the upper wrapper paper or the lower wrapper paper is located on the two-dimensional coordinate system, obtain the value of x1 - x2. When (x1 - x2) ≠ 0, according to the transmission offset amount of the upper wrapper paper or the lower wrapper paper, use two rectification stations to perform synchronous reverse rectification on the upper wrapper paper or synchronous reverse rectification on the lower wrapper paper. The specific implementation method is as follows: When (x1 - x2) > 0, adjust the rectification direction of the rectification station upstream for the upper wrapper paper or the lower wrapper paper to be the negative direction of the X axis, and the specific rectification amount is 1 / 2Py. Adjust the rectification direction of the rectification station downstream for the upper wrapper paper or the lower wrapper paper to be the positive direction of the X axis, and the specific rectification amount is 1 / 2Py; When (x1-x2) is less than 0, the correction direction of the upstream correction station for the upper or lower protective paper is adjusted to the positive direction of the X-axis, and the specific correction amount is 1 / 2Py. The correction direction of the downstream correction station for the upper or lower protective paper is adjusted to the negative direction of the X-axis, and the specific correction amount is 1 / 2Py.

[0046] If a single correction station is driven to perform correction work, the upper or lower face paper will deviate more from its original position. When (x1-x2)>0, the correction direction of the upper or lower face paper by the correction station located upstream is adjusted to be in the negative direction of the X-axis, and the specific correction amount is Py. At this time, the offset operation duration in this case is greater than the offset operation duration t1 of this embodiment.

[0047] When (x1-x2) is less than 0, the correction direction of the upper or lower cover paper by the upstream correction station is adjusted to the positive direction of the X axis, and the specific correction amount is Py. Similarly, the offset operation time in this case is greater than the offset operation time t1' of this embodiment.

[0048] Through the above comparison, it is obvious that the present embodiment uses two correction stations to perform synchronous reverse correction on the upper cover paper or the lower cover paper, so the correction amount in this step is 1 / 2Py, and the offset operation time of the present embodiment is relatively short.

[0049] After using two correction stations to perform synchronous reverse correction on the upper facing paper or the lower facing paper, there may be a situation where the facing paper after synchronous reverse correction is transmitted in a straight line, but it deviates from the original position. If it is not regulated, the upper facing paper and the lower facing paper will be offset from each other, affecting the subsequent production of gypsum boards.

[0050] Therefore, it is necessary to process the transmitted image of the upper cover paper or the lower cover paper after the first deflection correction to identify whether a second deflection correction is required. The specific implementation method is as follows: The transmission image of the upper cover paper or the lower cover paper after the correction is reconstructed to restore the standard two-dimensional coordinate system, and the standard coordinate value of the origin of the two-dimensional coordinate system in the standard two-dimensional coordinate system is determined. Based on the X coordinate value of the standard coordinate value, the two correction stations are regulated to perform synchronous and unidirectional correction. The implementation method of restoring the standard two-dimensional coordinate system is as follows: Find the corresponding feature points on the transmission image of the upper cover paper or the lower cover paper, and reconstruct and restore the standard two-dimensional coordinate system on the transmission image based on the standard two-dimensional coordinate values ​​of all the feature points; Determine the X coordinate value x0 of the origin of the two-dimensional coordinate system in the standard two-dimensional coordinate system; Among them, when the X coordinate value x0>0, the two correction stations are adjusted to correct the upper or lower face paper in the negative direction of the X axis, and the specific correction amount is ; When the X - coordinate value x0 < 0, the deviation - correction directions of the two deviation - correction stations for the upper facing paper or the lower facing paper are adjusted to the positive X - axis direction, and the specific deviation - correction amount is ; When the X - coordinate value x0 = 0, the two deviation - correction stations are not adjusted to work.

[0051] It should be particularly noted that the standard two - dimensional coordinate system is based on the transmission image obtained when there is no transmission offset of the upper facing paper or the lower facing paper. At this time, the standard two - dimensional coordinate system is constructed with the center - point position of the upper facing paper or the lower facing paper. At this time, the center - point position is the mid - point position in the width direction of the upper facing paper or the lower facing paper.

[0052] Therefore, when reconstructing the standard two - dimensional coordinate system on the transmission image of the upper facing paper or the lower facing paper after deviation - correction, the specific method for determining the origin of the standard two - dimensional coordinate system is to determine the origin of the standard two - dimensional coordinate system with the X - coordinate value and Y - coordinate value of the feature point whose position remains unchanged all the time.

[0053] After constructing the standard two - dimensional coordinate system, determine the X - coordinate value x0 of the origin of the two - dimensional coordinate system in the standard two - dimensional coordinate system. If the X - coordinate value x0 of the origin of the two - dimensional coordinate system in the standard two - dimensional coordinate system is 0, it means that the facing paper after the first deviation - correction adjustment returns to the original position, and no secondary deviation - correction is required.

[0054] When the X - coordinate value x0 of the origin of the two - dimensional coordinate system in the standard two - dimensional coordinate system is not equal to 0, according to the positive or negative value of the X - coordinate value, determine the deviation direction of the facing paper after the first deviation - correction adjustment relative to the original position, so as to determine the deviation - correction direction and the specific deviation - correction amount.

[0055] Based on the above - mentioned pre - coating device for the coating of the gypsum board facing paper, the present invention provides a pre - coating method for the coating of the gypsum board facing paper, including the following steps: Step 100: Carry out directional transmission on the upper facing paper. Through directional transmission, the inner surface of the upper facing paper is adjusted from the upward state to the downward state, and the inner surface of the lower facing paper is always kept upward for transmission; Step 200: Construct the standard two - dimensional coordinate system corresponding to when there is no offset of the upper facing paper and the lower facing paper. Real - time monitor the transmission images of the upper facing paper and the lower facing paper during the transmission process. Construct two - dimensional coordinate systems with the center - points of the upper facing paper and the lower facing paper respectively, and calculate the transmission offset amounts of the upper facing paper and the lower facing paper respectively; Step 300: Respectively set two rectifying stations upstream of the coating and rolling stations of the upper facing paper and the lower facing paper. According to the transmission offset of the upper facing paper and the lower facing paper, use the two rectifying stations to synchronously and reversely rectify the upper facing paper or synchronously and reversely rectify the lower facing paper. Compare the origin coordinate values of the two-dimensional coordinate systems of the rectified upper facing paper and the lower facing paper with the standard two-dimensional coordinate system, and regulate the two rectifying stations of the upper facing paper and the lower facing paper to synchronously and co-directionally rectify according to the comparison result; Step 400: Pour coating gypsum slurry on the inner surfaces of the upper facing paper and the lower facing paper in the upward state respectively, and use the coating and rolling method to form a reinforcing coating on the inner surfaces of the upper facing paper and the lower facing paper; Step 500: Pour the original gypsum slurry on the inner surface of the lower facing paper. After the original gypsum slurry spreads, press the upper facing paper with the upper facing paper against the upper surface of the spread original gypsum slurry.

[0056] In the production process of traditional facing paper gypsum boards, the formed gypsum slurry is usually laid on the lower facing paper, and the upper facing paper is pressed to adhere to the formed gypsum slurry. Only relying on the viscosity of the formed gypsum slurry to achieve the bonding work between the lower facing paper and the upper facing paper. When drying the gypsum board, the viscosity between the facing paper as the heated surface and the gypsum slurry is easily damaged by high temperature. The bonding of the board is better, but it is easy to peel off the paper, resulting in low strength of various parts of the gypsum board.

[0057] In this embodiment, on the production line of gypsum boards, before pouring the gypsum slurry onto the lower facing paper, coating gypsum slurry is applied to the inner surface of the upper facing paper and the inner surface of the lower facing paper. It can also be a single inner surface of the upper facing paper or the inner surface of the lower facing paper coated with coating gypsum slurry. Specifically, the facing paper coated with coating gypsum slurry is selected according to the installation position of the heating pipes in the drying chamber, so as to add a layer of high-density gypsum slurry on the upper paper surface. After adding, during the drying process, it protects the interaction between the surface layer of the facing paper and the gypsum crystals, so as not to be damaged by high temperature, thereby improving the adhesion between the upper facing paper and the lower facing paper and the formed gypsum slurry.

[0058] In addition, based on the upper facing paper and the offset of the upper facing paper during transmission, in this embodiment, by actively rectifying the upper facing paper and the lower facing paper, it is ensured that the coating distribution state formed on the inner surfaces of the upper facing paper and the lower facing paper always remains stable, and the coating gypsum slurry is always symmetrically laid flat on the facing paper, ensuring that the reinforcing coatings formed on the inner surfaces of the upper facing paper and the lower facing paper are symmetrically distributed about the central axis of the lower facing paper, and the widths of the blank areas left on both sides of the upper facing paper and the lower facing paper are the same. The reinforcing coating formed on the inner surface of the upper facing paper is symmetrically distributed about the central axis of the upper facing paper, and the widths of the blank areas left on both sides of the upper facing paper are the same. Therefore, the adhesion between the upper facing paper and the lower facing paper and the formed gypsum slurry is evenly dispersed, ensuring that the upper facing paper and the lower facing paper will not have the situation of paper peeling and bulging.

[0059] The above embodiments are only exemplary embodiments of the present application and are not used to limit the present application. The protection scope of the present application is defined by the claims. Those skilled in the art can make various modifications or equivalent replacements within the essence and protection scope of the present application, and such modifications or equivalent replacements should also be regarded as falling within the protection scope of the present application.

Claims

1. A precoating device for the coating of the facing paper of gypsum board, characterized in that, Comprising: A coating roll-pressing assembly (1), including a discharging unit (101) and a coating roll unit (102) arranged downstream of the discharging unit (101), for forming a reinforcing coating on the inner surfaces of the upper facing paper and the lower facing paper by means of coating and roll-pressing; A first turning roller assembly (2), arranged downstream of the coating roll-pressing assembly (1), for adjusting the inner surface of the upper facing paper from an upward state to a downward state; A visual monitoring assembly (3), respectively installed above the inner surface of the upper facing paper in an upward state and above the inner surface of the lower facing paper, for taking transmission images of the upper facing paper and the lower facing paper before coating; A deviation rectifying mechanism (4), arranged upstream of the coating roll-pressing assembly (1), the deviation rectifying mechanism (4) includes two deviation rectifying guide rollers, and when the upper facing paper and the lower facing paper are being transmitted, they respectively pass through the two deviation rectifying guide rollers in sequence; The visual monitoring assembly (3) and the deviation rectifying mechanism (4) are connected to a processing system (5), the processing system (5) obtains the offset amounts of the upper facing paper and the lower facing paper before coating based on the monitoring results of the visual monitoring assembly (3), and the processing system (5) controls the operation of the deviation rectifying mechanism (4) based on the offset amounts.

2. The pre-coating device for a gypsum board facing paper coating according to claim 1, wherein: When the processing system (5) processes the monitoring results of the visual monitoring assembly (3), the specifically used modules include: An image processing module (51), for performing image processing on the transmission images of the upper facing paper and the lower facing paper taken by the visual monitoring assembly (3), so as to be able to identify the straight lines where the two side edges of the upper facing paper and the lower facing paper are located, and intercept the transmission images, retaining the clear images of the two side edges of the upper facing paper and the lower facing paper as the analysis objects; A real-time coordinate system construction module (52), for constructing a real-time two-dimensional coordinate system with the center position of the width of the facing paper of the analysis object as the origin; An offset calculation module (53), based on the real-time coordinate system construction module (52), selects end point reference points from the straight lines of the two side edges of the upper facing paper and the lower facing paper, determines the offset direction of the facing paper based on the coordinates of the end point reference points, and determines the offset amount of the facing paper based on the coordinates of the reference points on the two side edges; A standard coordinate system construction module (54), taking the transmission image of the facing paper when there is no offset as the reference image, constructing a standard two-dimensional coordinate system with the center position of the width of the facing paper of the reference image as the origin, selecting feature points from the reference image, and determining the standard coordinate values of the feature points in the standard two-dimensional coordinate system; A deviation rectifying control module (55), based on the determined offset direction and offset amount of the facing paper, controls the two deviation rectifying guide rollers of the deviation rectifying mechanism (4) to work synchronously and in opposite directions, and the controlled offset amount of the two deviation rectifying guide rollers of the deviation rectifying mechanism (4) is half of the offset amount. The standard two-dimensional coordinate system is reconstructed in the transmission image after correction based on the standard coordinate value of the feature point, a reference offset is determined based on the X coordinate value of the origin of the two-dimensional coordinate system in the standard two-dimensional coordinate system, and the two correction guide rollers of the correction mechanism (4) are regulated to work synchronously and in the same direction, and the regulated offset of the two correction guide rollers of the correction mechanism (4) is the reference offset.

3. A pre-coating device for gypsum board facing paper coating according to claim 2, characterized in that: The standard coordinate system construction module (54) constructs a standard two-dimensional coordinate system with the center points of the upper face paper and the lower face paper in a non-offset state, and the real-time coordinate system construction module (52) constructs a real-time two-dimensional coordinate system by real-time monitoring the center points of the upper face paper and the lower face paper; The offset calculation module (53) determines the inclination angle of the straight line where the side of the upper face paper or the lower face paper is located based on the real-time two-dimensional coordinate system, and calculates the oblique transmission offset of the upper face paper or the lower face paper in combination with the endpoint coordinate values ​​of the upper face paper or the lower face paper; The offset calculation module (53) calculates the center offset of the upper cover paper or the lower cover paper relative to the standard position based on the horizontal coordinate difference between the standard two-dimensional coordinate system and the real-time two-dimensional coordinate system.

4. A pre-coating device for gypsum board facing paper coating according to claim 2, characterized in that: The deflection correction control module (55) controls two deflection correction stations based on the oblique transmission offset to perform synchronous reverse deflection correction on the upper face paper or the lower face paper, until the upper face paper or the lower face paper is corrected to be transmitted in a straight direction; The deflection correction and control module (55) compares the origin coordinate values ​​of the real-time two-dimensional coordinate system of the upper face paper and the lower face paper after deflection correction with the standard two-dimensional coordinate system, and controls the two deflection correction stations of the upper face paper and the lower face paper to perform synchronous and same-direction deflection correction according to the comparison result, so that the upper face paper or the lower face paper is corrected to be transmitted in a straight line along the standard point position.

5. The pre-coating device for gypsum board facing paper coating according to claim 3, characterized in that: The real-time coordinate system construction module (52) constructs a real-time two-dimensional coordinate system with the center point of the upper face paper photographed in real time, and the implementation method is the same as the implementation method of constructing a real-time two-dimensional coordinate system with the center point of the lower face paper photographed in real time, specifically: Performing image processing on the transmission images of the upper and lower face paper during the transmission process, respectively, so as to identify the straight lines where the two side edges of the upper face paper are located and the straight lines where the two side edges of the lower face paper are located; The areas with obvious marks on both sides of the lower face paper are taken as analysis objects, and the center positions of the upper face paper and the lower face paper are determined. With the center positions of the upper face paper and the lower face paper as the origin, a two-dimensional coordinate system is constructed respectively, wherein the X-axis is parallel to the width direction of the upper face paper and the lower face paper, and the Y-axis intersects the X-axis perpendicularly.

6. A pre-coating device for gypsum board facing paper coating according to claim 5, characterized in that: Select multiple groups of symmetric reference points on the straight lines where the two side edges of the upper facing paper are located, and determine the coordinate values corresponding to the multiple groups of reference points on the straight lines where the two side edges of the upper facing paper are located; Based on the coordinate values corresponding to at least two reference points on the single side edge of the upper facing paper obtained in sequence, the offset calculation module (53) determines the transmission offset direction of the upper facing paper; The offset calculation module (53) calculates the coordinate values corresponding to the multiple groups of reference points on the two side edges of the upper facing paper, and calculates the difference in the X coordinate values of the same group of reference points on the two side edges of the upper facing paper to calculate the transmission offset amount of the upper facing paper; Select multiple groups of symmetric reference points on the straight lines where the two side edges of the lower facing paper are located, and determine the coordinate values corresponding to the multiple groups of reference points on the straight lines where the two side edges of the lower facing paper are located; Based on the coordinate values corresponding to at least two reference points on the single side edge of the lower facing paper obtained in sequence, determine the transmission offset direction of the lower facing paper; The offset calculation module (53) calculates the coordinate values corresponding to the multiple groups of reference points on the two side edges of the lower facing paper, and calculates the difference in the X coordinate values of the same group of reference points on the two side edges of the lower facing paper to calculate the transmission offset amount of the lower facing paper.

7. The precoating device for the coating of the facing paper of a gypsum board according to claim 6, wherein: Sequentially obtain the coordinate values x1, x2,... corresponding to at least two reference points along the straight line of the single side edge of the upper facing paper or the lower facing paper, and calculate x1 - x2; If (x1 - x2) > 0, then the transmission offset direction of the upper facing paper or the lower facing paper is the positive direction, If (x1 - x2) < 0, then the transmission offset direction of the upper facing paper or the lower facing paper is the negative direction; If (x1 - x2) = 0, then there is no transmission offset of the upper facing paper or the lower facing paper; Among them, when (x1 - x2) = 0, the upper facing paper or the lower facing paper at this time is expressed as having no transmission offset, and the standard coordinate system construction module (54) constructs a two-dimensional coordinate system for the transmission image of the upper facing paper or the lower facing paper at this time, and uses this two-dimensional coordinate system as the standard two-dimensional coordinate system corresponding to the upper facing paper and the lower facing paper without offset; Select an object with a constant position from the transmission image of the upper facing paper or the lower facing paper as a feature point, and determine the two-dimensional coordinate values of the feature point in the standard two-dimensional coordinate system.

8. The precoating device for the coating of the facing paper of a gypsum board according to claim 3, wherein: The offset calculation module (53) respectively determines the X coordinate values x1a, x1b, x2a, x2b of the upper and lower two sets of end points on the two side edges of the lower facing paper or the upper facing paper; The calculation formula for the transmission offset is as follows: .

9. The precoating device for the coating of the facing paper of a gypsum board according to claim 8, wherein: According to the inclination of the straight line where the single side edge of the upper facing paper or the lower facing paper is located in the two-dimensional coordinate system, obtain the value of x1 - x2. When (x1 - x2) ≠ 0, according to the transmission offset amount of the upper facing paper or the lower facing paper, use two rectification stations to perform synchronous reverse rectification on the upper facing paper or synchronous reverse rectification on the lower facing paper; Among them, when (x1 - x2) > 0, the deviation rectification control module (55) controls the deviation rectification direction of the upstream deviation rectification station for the upper facing paper or the lower facing paper to be the negative direction of the X-axis, and the specific deviation rectification amount is 1 / 2Py. The deviation rectification direction of the downstream deviation rectification station for the upper facing paper or the lower facing paper is the positive direction of the X-axis, and the specific deviation rectification amount is 1 / 2Py; When (x1 - x2) < 0, the deviation rectification control module (55) controls the deviation rectification direction of the upstream deviation rectification station for the upper facing paper or the lower facing paper to be the positive direction of the X-axis, and the specific deviation rectification amount is 1 / 2Py. The deviation rectification direction of the downstream deviation rectification station for the upper facing paper or the lower facing paper is the negative direction of the X-axis, and the specific deviation rectification amount is 1 / 2Py.

10. A pre-coating device for a gypsum board facing paper coating according to claim 9, wherein: After the deviation rectification control module (55) uses two deviation rectification stations to perform synchronous reverse deviation rectification on the upper facing paper or synchronous reverse deviation rectification on the lower facing paper, a standard two-dimensional coordinate system is reconstructed and restored from the transmission image of the rectified upper facing paper or the lower facing paper, and the standard coordinate value of the origin of the two-dimensional coordinate system in the standard two-dimensional coordinate system is determined. Based on the X coordinate value of the standard coordinate value, the two deviation rectification stations are controlled to perform synchronous forward deviation rectification to restore to the standard two-dimensional coordinate system: Find the corresponding feature points from the transmission image of the upper facing paper or the lower facing paper, and based on the standard two-dimensional coordinate values of all the feature points, reconstruct and restore the standard two-dimensional coordinate system on the transmission image; Determine the X coordinate value x0 of the origin of the two-dimensional coordinate system in the standard two-dimensional coordinate system; Among them, when the X coordinate value x0 > 0, the deviation correction control module (55) controls the deviation correction directions of the two deviation correction stations for the upper or lower facing paper to be the negative direction of the X axis, and the specific deviation correction amount is ; When the X coordinate value x0 < 0, the deviation rectification control module (55) controls the deviation rectification directions of the two deviation rectification stations for the upper facing paper or the lower facing paper to be the positive direction of the X axis, and the specific deviation rectification amount is ; When the X coordinate value x0 = 0, the deviation rectification control module (55) does not control the two deviation rectification stations to work.

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