JP2018135630A - Process for determining feature of fabric - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide apparatuses, processes, and systems for determining features of a paper-making fabric.SOLUTION: The apparatuses, processes, and systems utilize a representation of a portion of a surface of the fabric, with the representation showing locations and sizes of knuckles and pockets in the surface of the fabric. An image of the portion of the fabric is generated based on the representation. Using the displayed image, an outline is drawn around at least one of the knuckles, and guidelines are drawn such that the guidelines pass through the center of the outlined knuckle, pass through the other knuckles, and form a shape that surrounds areas of the image that correspond to where the pockets are formed between the knuckles. With the outlined knuckle and guidelines, properties that affect the paper-making functionality of the fabric may be calculated.SELECTED DRAWING: Figure 3A

Description

  The present invention relates to characterizing the surface of a papermaking fabric. In particular examples, the present invention relates to an apparatus, method and system for determining the properties of the contact surface of a fabric used to form a three-dimensional structure of a web in a papermaking process.

  In the process of forming paper products such as tissue paper and paper towels, while the papermaking web (papermaking raw material) is still highly deformable, i.e. when the papermaking web has a high moisture content, 3 Dimensional molding is performed. In many cases, this three-dimensional shaping of the web is performed on a structuring fabric, which is a fabric. The fabric provides a contact surface composed of knuckles in the yarns of the fabric (intersections where the warps intersect the wefts and are woven into the tissue and exposed to the surface), and the pockets are between the knuckles Formed in the fabric. When the papermaking web is applied to the fabric, a portion of the web contacts the knuckle and the other portion of the web is drawn into the pocket. Prior to removal from the fabric, the web is dried to such an extent that its shape is fixed or locked. Thereby, a dome is formed in the dry web, where the web is drawn into a pocket in the fabric, and the dome is present in the finished paper product. Thus, the paper product has a unique three-dimensional structure formed in part by the knuckle and pocket characteristics of the structuring fabric.

  Since the contact surface of the structuring fabric is directly related to the shape of the finished product, the selection of the structuring fabric is often based on the desired product shape. However, it is difficult to characterize the contact surface of the structuring fabric based on a simple visual inspection of the fabric. Although the fabric knuckle can be easily seen, it is difficult to accurately determine the size of the knuckle, it is difficult to determine the area of the pocket between the knuckles, and the papermaking web is pulled in during the papermaking process It is often difficult to determine the depth of the pockets that will be made. Thus, there are previous techniques that attempt to quantify the properties of the contact surface of the fabric using, for example, a formula based on the yarn parameters of the fabric. However, such formulas are often not accurate enough to characterize the contact surface of the fabric so as to allow an accurate prediction of the paper product structure that will be formed by the fabric. Has been issued. Furthermore, the contact area characteristics will often change when the fabric is run on a paper machine. For example, wear on the surface of the fabric will generally increase the length of the knuckle, thereby changing the composition that will be imparted on the web by the fabric. Thus, the formula for determining the contact surface properties that apply to the initial fabric configuration does not necessarily apply to fabrics that have worn over time.

  Accordingly, it would be beneficial to provide a technique for accurately characterizing the contact area characteristics of a structuring fabric used in a papermaking process. Moreover, it would be beneficial to provide a technique that can easily determine contact area characteristics as the fabric wears over time while the fabric is mounted on a paper machine.

US Pat. No. 7,494,563 US Pat. No. 6,350,336

  According to a first aspect, the present invention provides a method for determining fabric characteristics. The method includes forming a representation of a portion of the surface of the fabric, the representation being a knuckle in the surface of the fabric (an intersection where the warp intersects the weft and is woven into the tissue and exposed to the surface). At least a portion of the image on a screen associated with a computer having a processor, and a step of generating an image of a portion of the surface of the fabric based on the representation; And contouring around at least one of the knuckles in the displayed image. The method is the step of drawing a guideline in the displayed image, wherein the guideline passes through (i) the center of the outlined knuckle, (ii) passes through the other knuckle, and (iii) the pocket knuckles The method further includes the step of drawing to form a shape surrounding an area of the image corresponding to the location formed therebetween. The contours and guidelines are drawn using an image analysis program stored in a non-transitory computer readable medium.

  According to a second aspect, the present invention provides a method for determining fabric characteristics. The method includes forming a representation of a portion of the surface of the fabric, wherein the representation indicates the location and size of the knuckles and pockets in the surface of the fabric, the representation being a print of the fabric surface, and A step, which is one of the photographs of the surface of the fabric. A method generates, based on the representation, an image of a portion of the surface of the fabric; displays at least a portion of the image on a screen associated with a computer having a processor; and knuckles in the representation representation. The method further includes determining a size and location, and determining a pocket size and location in the representation representation. The method also includes drawing a unit cell for a portion of the surface of the fabric in the displayed image, where the unit cell is defined by a guideline, and the guideline passes through the center of the (i) knuckle. (Ii) forming a shape surrounding an area of the image corresponding to where the pockets are formed between the knuckles. Based on the properties of the unit cells formed by the guidelines, at least one property of the surface of the fabric is calculated, and the contours and guidelines are stored using an image analysis program stored in a non-transitory computer readable medium. be painted.

1 is a schematic diagram of a paper machine using a structuring fabric. FIG. 3 is a top view of a section of a structuring fabric. 1 is a diagram of a contact surface printing apparatus according to the present invention. FIG. 1 is a diagram of a contact surface printing apparatus according to the present invention. FIG. 3B is a detailed view of the press section of the print forming apparatus shown in FIGS. 3A and 3B. FIG. 2 is an example of a print of a structuring fabric made according to the present invention. 2 is an example of a print of a structuring fabric made according to the present invention. 2 is an example of a print of a structuring fabric made according to the present invention. 2 is an example of a print of a structuring fabric made according to the present invention. FIG. 6 illustrates steps for establishing a coordinate system for structuring fabric printing. FIG. 6 illustrates steps for establishing a coordinate system for structuring fabric printing. FIG. 6 illustrates steps for establishing a coordinate system for structuring fabric printing. FIG. 6 illustrates steps for establishing a coordinate system for structuring fabric printing. FIG. 6 illustrates steps for establishing a coordinate system for structuring fabric printing. FIG. 6 illustrates the application of the analysis technique herein applied to a photograph of a fabric knuckle. FIG. 6 illustrates the application of the analysis technique herein applied to a photograph of a fabric knuckle. FIG. 6 illustrates the application of the analysis technique herein applied to a photograph of a fabric knuckle. FIG. 5 shows an alternative analysis technique applied to fabric knuckle photos and prints. FIG. 5 shows an alternative analysis technique applied to fabric knuckle photos and prints. FIG. 4 illustrates the application of an analysis technique to determine a pocket surrounded by knuckles in a structuring fabric. FIG. 9 illustrates the application of an analysis technique for determining the depth of the pocket shown in FIG. FIG. 2 is an illustration of an image of a paper product and application of analysis techniques applied to its structuring fabric. FIG. 2 is an illustration of an image of a paper product and application of analysis techniques applied to its structuring fabric.

  The present invention relates to an apparatus, method and system for determining the properties of the contact surface of a fabric used in a papermaking process. As will become apparent from the discussion below, “fabric contact surface properties” refers to the contact surface properties resulting from the knuckle and pocket configurations that make up the fabric contact surface. In certain embodiments, the present invention is adapted for use with a structuring fabric used to form a three-dimensional structure of a web in a papermaking process. Such structuring fabrics are often constructed with yarns made from, for example, polyethylene terephthalate (PET), polyester, polyamide, polypropylene, and the like. As described further below, the specific contact surface of the structuring fabric will have a significant impact on the structure of the paper product, and the present invention utilizes techniques for characterizing aspects of the contact surface. To do. However, it should be noted that the present invention is applicable to any type of fabric used in the papermaking process, including fabrics used for purposes other than web structuring.

  FIG. 1 shows an example of a draft drying (TAD) papermaking process. In a draft drying (TAD) papermaking process, the structuring fabric 48 is used to form the three-dimensional structure of the paper product. To begin the process, a papermaking feed supplied through the headbox 20 is jetted into a nip formed between the forming fabric 24 and the transfer fabric 28. The forming fabric 24 and the transfer fabric pass between the forming roll 32 and the breast roll 36. The forming fabric 24 and the transfer fabric 28 are separated after passing between the forming roll 32 and the breast roll 36. The transfer fabric 28 then passes through the dewatering zone 40, where the suction box 44 removes moisture from the web and transfer fabric 28, thereby prior to transfer of the web to the structuring fabric 48. And increasing the web concentration from, for example, about 10% to about 25%. In some cases, a significant amount of creped fabric is imparted to the web in the transfer zone 56, particularly by so-called rush transfer, in which the transfer fabric 28 moves faster than the structuring fabric 48. When applied, it may be advantageous to apply some amount of vacuum in the transfer zone 56, as shown through the vacuum assist box 52.

  Since the web still has a high moisture content when transferred to the structuring fabric 48, the web is deformable and a portion of the web is formed between the yarns that make up the structuring fabric 48. (The structure of the pocket in the fabric will be described in detail below). As the structuring fabric 48 passes around the ventilators 60 and 64, the web concentration is increased, for example, from about 60% to about 90%. Thereby, the web is generally permanently shaped by the structuring fabric 48, which includes the dome. The dome is where the web is drawn into the pocket of the structuring fabric 48. Thus, the structuring fabric 48 provides (transfers) a three-dimensional shape to the web, which results in a paper product having a dome structure.

  By bringing the web into contact with the adhesive sprayed onto the Yankee cylinder 68 just prior to contacting the translating web to complete the paper forming process, the web is structured without significant degradation of its properties. It is transferred from the fabric 48 to the Yankee cylinder 68. After the web has reached a concentration of at least about 96%, light creping is used to remove the web from the Yankee cylinder 68.

  Although FIG. 1 illustrates one type of process in which a structuring fabric is used to impart a three-dimensional shape to a paper product, many of the structuring fabrics can be used to impart a three-dimensional structure to a paper product. There are other papermaking processes. For example, the structuring fabric can be used in a papermaking process that does not utilize draft drying (TAD). An example of such a non-TAD process is disclosed in US Pat. No. 7,494,563, the disclosure of which is incorporated by reference in its entirety. As will be appreciated by those skilled in the art, the invention disclosed herein is not limited to being used in any particular papermaking process, but rather to fabrics used in a wide variety of papermaking processes. Can be applied.

  FIG. 2 is a view of a portion of the structuring fabric 200 on the side facing the web. The fabric 200 includes a warp 202 and a weft 204, which will run in the machine direction (MD) when the fabric 200 is used in a papermaking process, and the weft 204 is used by the fabric 200 in a papermaking process. When run, run in the cross machine direction (CD). Warp and wefts 202 and 204 are woven together to form the structure of fabric 200. When looking down at FIG. 2, on the surface that contacts the web of the structuring fabric 200, some of the threads 202 and 204 shown are planes that contact the web during the papermaking process, i.e., contact of the fabric 200. Note that it is below (back) the surface. The uppermost points of threads 202 and 204 that define the plane of the contact surface are knuckles 206 and 208. That is, the knuckles 206 and 208 form the actual contact surface of the forming fabric 200. A pocket 210 (shown as an outlined area in FIG. 2) is defined in the area between the knuckles 206 and 208. During the papermaking operation, a portion of the web can be drawn into the pocket 210 and, as explained above, it is drawn into the pocket 210 that corresponds to the dome in the finished paper product. Part of the web.

  Note that the structuring fabric may not initially be manufactured with knuckles such as knuckles 206 and 208 of FIG. Instead, knuckles are often formed by sanding or polishing one of the surfaces of the structuring fabric. Furthermore, wear on the surface of the structuring fabric can further increase the knuckle length when the structuring fabric is used in a papermaking operation. As described below, the present invention provides for determining the properties of the knuckle, including the properties of the knuckle when the fabric is subjected to wear.

  It should also be noted that, for example, depending on the warp and weft weave and the size of the yarn, the structuring fabric can take many forms. The structuring fabric 200 shown in FIG. 2 includes a knuckle 206 formed on the warp 202 and a knuckle 208 formed on the weft 204. This can result from the sanding of the fabric 200 or from the wear of the fabric 200 to the point where the knuckle is formed on both the warp and wefts 202 and 204. However, with less sanding, the fabric 200 may have only the knuckle 206 on the warp 202 and no knuckle 208 on the weft 204, or vice versa. Numerous configurations of weft and warp yarns in a structuring fabric are known in the art, and multiple configurations allow different shaped paper products to be formed by the fabric.

  An apparatus and technique for forming a print (transfer) of a contact surface formed by a fabric knuckle is shown in FIGS. 3A and 3B. FIG. 3A is a side view of the contact surface printing apparatus 300, and FIG. 3B is a front view of the contact surface printing apparatus 300. The device 300 includes a C-shaped frame structure 302 with first and second arms 303 and 305. The first plate 304 is movably supported by the first arm 303, and the stationary second plate 306 is supported by the second arm 305. A print of the fabric knuckle is formed between the first plate 304 and the second plate 306, as described in detail below.

  The first plate 304 is operatively connected to a hydraulic pump 308 for actuating the movement of the first plate 304 toward the second plate 306. In some embodiments, the hydraulic pump 308 is manual and includes a release valve to allow the first plate 304 to be retracted from the second plate 306. However, the pump 308 can take many other forms to achieve movement of the first plate 304. The pump 308 may be connected to a transducer and transducer indicator 310 for measuring the pressure applied to the first plate 304 by the pump 308 when the first plate 304 is pressed against the second plate 306. . As a specific example, Milwaukee, Wisconsin, Actuant Corp. ENERPAC (R) Hydrological Hand Pump Model CST-18381 can be used. Specific examples of pressure transducers are available from Transducer Technologies, Inc. of Temecula, California. A Transducer Technologies Load Cell Model DSM-5K with a corresponding indicator may be used. Of course, in other embodiments, the pump 308 and the transducer and transducer indicator 310 may be combined into a single unit.

  The frame 302 of the contact surface printing device 300 includes a wheel 312 adjacent to the front end of the frame 302 and a mount 313 that can be used to hold the pump 308 and / or the transducer 310. One or more wheels provided on the frame 312 make it easier for the frame 302 to move. According to an embodiment of the present invention, an advantageous feature of the contact surface printing device 300 is its portability. For example, with a configuration such as that shown in FIGS. 3A and 3B, the printing device 300 can be easily moved around a section of fabric that is mounted on a paper machine. As will be appreciated by those skilled in the art, the ability to form a print on the contact surface of the fabric while it is mounted on a papermaking machine, and thus characterizing the fabric according to the techniques described below The ability to do offers numerous benefits. As one example, the wear of the fabric on the paper machine is easily monitored by using the contact surface printing device 300, and after different periods of paper machine operation, the fabric knuckle print (transfer). Draw so that you can take things.

  The contact surface printing apparatus 300 shown in FIGS. 3A and 3B includes a frame structure 302 that connects a first plate 304 and a second plate 306, but in other embodiments, the contact surface printing apparatus includes: Such a single frame structure 302 may not be included. Instead, the first and second plates 304 and 306 may be unconnected structures, which are individually aligned to form a fabric print. In still other embodiments, the plates 304 and 306 can take very different forms than those shown in FIGS. 3A and 3B. For example, one of plates 304 and 306 may be formed as an enlarged surface, while the other plate is formed as a circular structure that is rolled across the enlarged surface. The term “plate”, as used herein, is a broad term that encompasses any structure sufficient to contact and / or support a component for making a fabric print. Further, as will be clear from the above description, the relative motion of the first and second plates 304 and 306 of any embodiment can be reversed while the first plate 304 remains stationary. The second plate 306 is drawn to be movable. FIG. 4 is a detailed view of section A of the contact surface printing device 300 shown in FIG. 3A, which is set up to produce a print of a section of fabric 312. FIG. The fabric 312 is positioned between the plate 304 and the plate 306, and the strip of pressure measurement film 314 is positioned opposite the structuring fabric 312. Between the pressure measurement film 314 and the first plate 304 is one or more sheets of paper 316. There is a strip of rubber 318 between the fabric 312 and the second plate 306.

  A pressure-measuring film is a material structured so that applying a force to the film ruptures the microcapsules in the film, allowing an instantaneous and permanent high-resolution image to be produced in the contacted area of the film. Produce inside. An example of such a pressure measuring film is sold as a Prescale film by Fuji Film Holdings Co., Ltd. in Tokyo, Japan. Another example of a pressure measuring film can be found in Sensor Products, Inc. of Madison, New Jersey. By PRESSUREX-MICRO®. Those skilled in the art will appreciate that other types of pressure measurement films can be used in the printing techniques described herein. In this regard, with respect to the analytical technique described below, the pressure measurement film need not provide an indication of the actual pressure applied to the film by the fabric, but rather the pressure measurement film is not by the fabric knuckle. Note that it is only necessary to provide a printed image showing the contact surface to be formed.

  The pressure applied to the plate 304 is to simulate the pressure that will be applied to the web opposite the fabric 312 in the actual papermaking process when forming a print of the fabric 310 on the pressure measuring film 314. Can be selected. That is, the pump 308 can be used to generate pressure (as measured by the transducer 310) on the plate 304, which is the pressure that will be applied to the web opposite the fabric 312 in the papermaking process. To simulate. In the papermaking process described above in connection with FIG. 1, the simulated pressure will be the pressure applied from the fabric 48 to the web facing the Yankee cylinder 68. In some papermaking processes, such as the method described in the aforementioned US Pat. No. 7,494,563, the pressure applied to the web opposite the fabric is generally in the range of 600 psi. Thus, to simulate this papermaking process, 600 psi of pressure will be applied to the plate 304 by the hydraulic pump 308 when forming an image of the knuckle of the fabric 312 in the pressure measurement film 314. . With regard to such operation, it has been found that Prescale film with medium pressure of 10-50 MPa by Fuji Film can provide a good image of the knuckle of the structuring fabric.

  Referring again to FIG. 4, the paper 316 serves as a cushion to improve the printing of the fabric 312 formed on the pressure measurement film 314. That is, the paper 316 provides a compressible and smooth surface so that the knuckle of the fabric 312 can “sink” into the pressure measuring film 314, which is the knuckle of the knuckle in the film 314. Form a high resolution image. To provide these properties, construction and craft are examples of paper types that can be used for paper 316.

  The strip of rubber 318 creates a horizontal contact surface for supporting the fabric 314. In an embodiment of the invention, plates 304 and 306 are made from a metallic material such as steel. The steel sheet is most likely to have imperfections that reduce the quality of the fabric knuckle print formed in the pressure measuring paper 316. However, the paper 316 and rubber 318 used between the plates 304 and 306, as well as the pressure measuring film 314 and fabric 312 provide a contact surface that is more horizontal than the surfaces of the metal plates 304 and 306. Thereby forming a better image in the pressure measurement film 314. As an alternative to paper 316 and rubber 318, those skilled in the art will appreciate that other materials can be used as the structure to provide a horizontal surface between plate 304 and plate 306 of device 300. .

  In other embodiments, the print is made from a fabric knuckle in a material other than the pressure measurement film. Another example of a material that can be used to form film prints is wax paper. A print of the fabric contact surface can be made in the wax surface by pressing the fabric contact surface against wax paper. Prints in wax paper can be made using plates 304 and 306 in the print forming apparatus 300 described above, or can be made by other configurations of plates. The wax paper print can then be analyzed in the same manner as the pressure measurement film print, as described below.

  FIGS. 5A-5D show an example of a knuckle print formed in a pressure measuring film using a contact surface printing device 300. FIG. In these prints, it is possible to see the unique shape and pattern of the fabric knuckle. As discussed above, the knuckle forms a contact surface for the fabric. Thus, a high resolution print of a knuckle in a pressure measurement film, such as that shown in FIGS. 5A-5D, provides a good representation of the contact surface of the fabric.

  Next, a system for analyzing a knuckle print, such as that shown in FIGS. 5A-5D, will be described. Within the system, graphical analysis is performed on a conventional computer system. Such a computer system is such as at least one computer processor (eg, central processing unit or processing units) connected to a communication infrastructure (eg, communication bus, crossover bar device, or network), etc. Well-known components. A further component of the computer system is a display interface (or other output interface) that transfers video graphics, text, etc. for display on a display screen. The computer system may further include common components such as a keyboard, mouse device, main memory, hard disk drive, removable storage drive, network interface, and the like.

  As a first step in the analysis, a print of the contact area of the fabric knuckle is converted into a computer readable image using a photo scanner. Any type of photo scanner can be used to generate a computer readable image. However, in certain embodiments, it has been found that a photo scanner having at least 2400 dpi provides a good image for analysis. Depending on the resolution of the image scan, an imaging analysis program (as described below) can apply an accurate scale to the image. As explained below, accurate scaling will be used in the calculation of the surface properties of the structuring fabric.

  The scanned image can be stored in a non-transitory computer readable medium to facilitate the analysis described below. As used herein, non-transitory computer readable media includes all computer-readable media except for temporary propagated signals. Examples of non-transitory computer readable media include, for example, hard disk drives and / or removable storage drives that represent disk drives, magnetic tape drives, optical disk drives, and the like.

  The scanned image as well as the characteristics of the contact surface scanned image determined according to the techniques described below can be associated with a database. As used herein, “database” means a collection of data organized in such a way that a computer program quickly selects a desired piece of data, such as an electronic filing system. ing. In some implementations, the term “database” may be used as a shorthand for “database management system”.

  An image analysis program is used with the scanned image of the fabric knuckle to perform a quantitative analysis of the scanned print image. Such image analysis programs are developed, for example, by computational software that works with graphical images. One example of such computational development software is MATMATICA® by Wolfram Research, LLC of Champaign, Illinois. As described below, the image analysis program will be used to specifically identify knuckles in the fabric print image of the structuring fabric, and the image may be imaged by known scaling of the fabric print image. The analysis program can calculate the size of the knuckle and estimate the size of the pocket.

  When analyzing a scanned image, any size region including multiple knuckles and pockets can be used for the analysis described below. In certain embodiments, an area of 1.25 inches x 1.25 inches (3.175 x 3.175 centimeters) of the fabric image is a pocket size using the techniques described herein. It has been found to allow a good estimation of properties such as In particular, when the image is formed using 2400 dpi resolution (discussed above) and 1.25 inches x 1.25 inches (3.175 x 3.175 cm) of the image for analysis. It has been found that good characterization of the contact surface can be performed when using the (meter) area. Of course, other resolutions and / or regions may provide good results.

  6A-6E show the steps for identifying knuckles in the enlarged portion of the scanned image of the print using the image analysis program. Initially, as shown in FIG. 6A, an enlarged portion of the image 600 is seen on the display screen of the computer system running the analysis program. Image 602 may be formed using the printing techniques described above, and image 602 shows knuckle 602. Along with using the image 600 by the analysis program, the scaling of the image 600 can be input into the analysis program. Such a scaling can be input, for example, as 2400 dpi, and then the analysis program can apply the scale SC to the image 600. The analysis program will then use the scale to calculate the knuckle size and position, as described below.

  6B and 6C show steps for identifying a particular knuckle 602A using an analysis program. Knuckle 602A is initially selected based on its location in the central region of magnified image 600. In this step, the rough contour of the knuckle 602A is applied. The rectangular box 604 can be a shape stored in the analysis program, and the rectangular box 604 is first applied around the knuckle 602A to initiate the knuckle identification process. The initial rectangular box 604 shape can then be refined more carefully to match the shape of the knuckle 602A, as shown in FIG. 6C. In this case, the ends 606 and 608 are again shaped to be more rounded and thus more accurately correspond to the end of the knuckle 602A. Although not shown, further refinement can be performed on the contour of the knuckle 602A until sufficient matching is achieved. Such refinement can be done by further enlarging the image 600.

  As shown in FIG. 6D, guidelines 610 and 612 are drawn after knuckle 602A is identified by a contour. Guidelines 610 and 612 are each drawn to pass through the center of the knuckle 602A and extend in a straight line through the center of the other knuckle. Also, in particular, guidelines 610 and 612 are depicted such that the pockets do not intersect the area formed in the fabric, which area is known to correspond to the area between the knuckle groups. Yes. By drawing the guide lines 610 and 612 straight between the centers of the knuckles, the guide lines 610 and 612 do not intersect the area of the pocket formed between the knuckles.

  After guidelines 610 and 612 have been drawn, additional guidelines are drawn, as shown in FIG. 6E. These guidelines are similar to guidelines 610 and 612, i.e., drawn through the center of the knuckle and do not pass through the area where the pocket is formed. Lower magnification can be used to assist in the process of drawing guidelines. By guidelines, a coordinate system is effectively established with respect to the position of the knuckle. Thus, the analysis program can now identify the size and shape of the knuckle based on the contour 602A and can identify the location of the knuckle as determined by the point where the guidelines intersect It is. The analysis program further includes a scale SC with an image 600 input. Thus, the analysis program will be able to apply the scale to the contour knuckle 602A and knuckle positioning to calculate the actual size and spacing of the knuckle. Similarly, it is noted that the analysis program can calculate the frequency of the guideline, such as the number of times the guideline 612 crosses the guideline 610 per unit length. The frequency of each set of guidelines 610 and 612 will be used in the calculation of fabric properties and in other aspects of the invention will be used as described below.

  As shown in FIGS. 6D and 6E, the knuckles are all the same size and are all the same shape, and the knuckles are regularly spaced along the guidelines. Please note that. This is not surprising. The reason for this is that most fabrics for papermaking machines are manufactured with a highly consistent yarn pattern, which results in a consistent knuckle size and position. The knuckle size, shape, and installation consistency are based on a single selected knuckle or on the limited number of identified knuckles for all knuckles on the fabric contact surface. Allows accurate estimation of size and shape, and a precise estimation of knuckle size and location can be achieved without identifying each knuckle. Of course, to achieve additional accuracy, two or more knuckles can be identified, and contours and guidelines can be drawn in different parts of the image.

  As shown in FIG. 6E, guidelines 610 and 612 define a plurality of unit cells. A particular unit cell 613 is shown between the guideline segments 610A, 610B, 612A, and 612B. The unit cell 613 effectively indicates the smallest repeating pattern in the fabric and the maximum allowable pocket size. The fabric shown in FIGS. 6A-6E has approximately one warp knuckles per unit cell, while other fabrics have more than one warp knuckles and / or 2 per unit cell. Note that it is possible to have more than one weft direction knuckle. In other words, the unit cell defined by the knuckle pattern will vary with different fabric patterns.

  As will be readily apparent to those skilled in the art, any or all of the steps shown in FIGS. 6A-6E can be performed by the user on the display screen, or alternatively, run the analysis program It can be either automated as done by. That is, the analysis program is configured to automatically identify the knuckle as a dark area of the image, delineate the knuckle, and then draw a guideline based on the identified knuckle, as described above. Can be done.

  After the selected knuckle is identified, and after guidelines are established through the knuckle, multiple properties of the fabric can be calculated using the knuckle size and position determined by the analysis program. To perform such calculations, the knuckle size and positioning data can be exported from the analysis program to a conventional spreadsheet program to calculate the properties of the fabric. Examples of decisions made by the analysis program and the calculations that follow from such decisions are shown in Table 1.

  The fabric obtained from image 600 contained only knuckle 602 on the warp. However, other fabrics can include knuckles on the weft threads, such as the fabric that formed the print of FIGS. 5B and 5D. With such a fabric, the knuckle on the weft can be identified using the contouring technique described above, and the guidelines can be used for the weft direction knuckle using the technique described above. Can be drawn through.

  The contact surface of the fabric may be characterized, for example, by using a fabric knuckle print (transfer) formed by the contact surface printing device 300, but in other embodiments the image of the contact surface of the fabric is Can be obtained differently. An alternative to forming a fabric knuckle print is to photograph the fabric knuckle and then use the procedures and techniques described above for analyzing the image formed from the photograph. . In this regard, it has been found that photographs having 2400 dpi provide sufficiently high and low resolution to be analyzed by the techniques described herein.

  An example of a photograph 700 of a portion of a papermaking fabric with a knuckle 702a is shown in FIG. 7A, and applying the analysis techniques described above to the image generated from the photograph 700 is shown in FIGS. 7C. Photo 700 of FIG. 7A shows fabric 701 next to ruler R. When the photograph is converted into an image for use with the analysis program, the scale for the image 700A can be entered based on the photographed ruler R. That is, the ruler R in the image 700A provides an input, and the analysis can apply a scale to the image from that input. The displayed image 700A is shown in FIG. 7B along with the scale SC.

  To identify the size and location of the knuckles in the image obtained from the fabric photo, the same technique described above with the image from the fabric print can be used. For example, outlined knuckle 702A and guidelines 710 and 712 are shown above image 700A in FIG. 7C. With the knuckle sizing and location data from the analysis program, all of the calculations described above can be performed to characterize the contact surface of the fabric 700 photographed.

  Table 2 below shows the results of the calculation of surface properties for the fabric, where one set of calculations is derived from a print of the fabric and the second set of calculations is derived from a photograph of the fabric. Yes.

  The results shown in Table 2 show that the contact surface characterization calculations realized using photographic techniques closely correspond to the calculations realized using fabric printing.

The techniques described above provide a good estimate of the fabric properties, especially when the unit cell shape formed by the guideline segments is substantially rectangular. However, if the unit cell shape formed by the guidelines is a non-rectangular parallelogram, an alternative technique can be used to provide a more accurate estimate of the fabric properties. An example of this alternative technique is shown in FIG. 8A, which is an image generated from a photograph of the surface of the fabric using the image analysis program described above. In this figure, unit cell 813 is defined by guideline segments 810A, 810B, 812A, and 812B. The unit cell 813 formed by the guideline segments 810A, 810B, 812A, and 812B has a substantially non-rectangular parallelogram shape. In this parallelogram, the angle θ is defined at the corner A where the guideline segments 810A and 812B intersect, and the angle θ is defined at the corner B where the guideline segments 810B and 812A intersect. This angle θ can be easily determined using an image analysis program based on the difference in the orientation angle of the guideline. In addition, the image analysis program determines the distance between guideline segments 810A and 810B (“DIST1”) and between guideline segments 812A and 812B based on the scale of the image as generally described above. It is possible to determine the distance ("DIST2"). Having determined the crossing angles θ, DIST1, and DIST2, the area of the unit cell (UCA) can be calculated using either formula (1) or formula (2).
UCA = (DIST1 / sin θ) × DIST2 (1)
UCA = (DIST2 / sin θ) × DIST1 (2)
Formulas (1) and (2) are derived from the standard formula for calculating the area of a parallelogram, ie area = base length × height, where DIST1 or DIST2 is a parallelogram The base length is then calculated from the sine of the angle θ and the other of DIST1 or DIST2.

  Table 3 shows examples of decisions made by the analysis program and the calculations that follow from such decisions when using an alternative technique based on area calculations of non-rectangular parallelogram unit cells.

  Some of the properties in Table 3 are determined or calculated in the same manner as described above in Table 1, but the knuckle density, total warp or weft knuckle contact area, contact area ratio Note that the percent area contribution, pocket area estimation, and pocket density characteristics are calculated in Table 3, unlike in Table 1. By considering the non-rectangular parallelogram shape of the unit cells, these different calculations provide a more accurate estimate of the properties of a fabric having non-rectangular parallelogram shaped unit cells.

  FIG. 8B is a print of a fabric made using the techniques described above. In this case, the fabric has overly non-rectangular unit cells, and one of the angles θ at the corners of the parallelogram defining the unit cells is about 140 degrees. To demonstrate the difference between the first technique described (which is not specifically adapted to parallelogram shaped unit cells) and the technique for non-rectangular parallelogram unit cells Two sets of calculations are performed on the fabric and the results are shown in Table 4.

  Note that some of the properties shown in Table 4 are the same for the two calculations, but the total in-plane contact area and pocket density are different. A calculation method adapted to a non-rectangular parallelogram unit cell takes into account the use of measurements that more closely match the actual inherent shape and structure of the fabric shown in FIG. The total in-plane contact area (ie, the percentage of fabric corresponding to the knuckle) and the pocket density determined by a computational technique specifically adapted to the quadrilateral unit cell will be more accurate. As those skilled in the art will appreciate, the total in-plane contact area and pocket density of the fabric have a significant effect on the papermaking properties of the fabric. Thus, the non-rectangular parallelogram calculation provides a more accurate estimate of the important properties of a given fabric.

  Another important property of the papermaking fabric is the depth to which the web can be drawn into pockets in the fabric during the papermaking process. As discussed above, a dome is formed in the final paper product, which corresponds to a portion of the web that is drawn into a pocket in the fabric. Thus, the pocket depth of the papermaking fabric directly affects the paper product formed using the fabric. Techniques for determining the pocket depth of the fabric will now be described.

  FIG. 9 shows an enlarged photograph of the structuring fabric. Using the pictures and using the image analysis program described above, the four knuckles K1-K4 are identified. The parallelogram is drawn so as to connect the knuckles K1 to K4, and the line of the parallelogram is drawn so as not to pass through the pocket area formed between the knuckles K1 to K4. With the parallelogram drawn, a profile direction line PL from the knuckle K1 through the center of the pocket to the knuckle K3 can be drawn. The profile direction line PL will be used to determine the pocket depth using a depth measuring instrument, as described below. Note that the profile direction line PL from knuckle K1 and knuckle K3 passes through the center of the pocket. As explained below, the pocket depth of the structuring fabric is determined as the depth in the pocket that cellulosic fibers can reach in the papermaking process. For the fabric shown in FIG. 9, the maximum fiber transition depth is in the center of the pocket. Thus, a profile direction line can alternatively be drawn through the center of the pocket from knuckle K2 to knuckle K4, and an alternative profile direction line can be used for pocket depth determination as described below. It will be. Also, different structuring fabrics will have different configurations of knuckles and pockets, but the profile direction lines are different structures just as the profile direction lines are determined as shown in FIG. One skilled in the art will understand that it can be readily determined with respect to the ring fabric.

  FIG. 10 is a screen shot of the program used to determine the profile of the structuring fabric pocket shown in FIG. The screen shot was made using a VHX-1000 digital microscope manufactured by Keyence Corporation of Osaka, Japan. The microscope was equipped with VHX-H3M application software, also provided by Keyence Corporation. A microscopic image of the pocket is shown in the upper part of FIG. In this image, the knuckles K'1 and K'3 and the pockets between the knuckles can be easily seen. A depth determination line DL is drawn from point D to point C, and the depth determination line DL passes through the knuckles K'1 and K'3 and the center of the pocket. The depth determination line DL is drawn so as to closely approximate the profile determination line PL shown in FIG. That is, based on an examination of the depth determination line DL derived using the knuckle and pocket image shown in FIG. 9, the user can enter the depth determination line DL in the microscope image shown in FIG. The depth determination line DL passes through the knuckles K′3 and K′1 and the region corresponding to the central portion of the pocket.

  By drawing the depth determination line DL, the digital microscope is then instructed to calculate the pocket depth profile along the depth determination line DL, as shown in the bottom portion of FIG. Can be done. The profile of the pocket is highest in the area corresponding to knuckles K'3 and K'1, and the profile falls to its lowest point in the center of the pocket. The pocket depth is determined from this profile as starting from the height of the knuckles K′3 and K′1, and the height of the knuckles K′3 and K′1 is determined by the line A above the depth profile. Marked. As with any two knuckles of the structuring fabric measured to this degree of accuracy, knuckles K'3 and K'1 do not have exactly the same height. Therefore, the height A is determined as the average between the two knuckles K'3 and K'1. The pocket depth is determined to end at a point just above the lowest point of the depth profile, which is marked by line B on the depth profile. As those skilled in the art will appreciate, the depth of the pocket from line A to line B roughly corresponds to the depth in the pocket at which cellulosic fibers in the web can migrate in the papermaking process. Note that the VHX-H3M software (discussed above) forms a complete depth profile from multiple slices in the fabric thickness direction. It should also be noted that when forming the depth profile, the VHX-H3M software uses a filtering function to smooth the depth profile formed from the thickness slice. Note that the measured pocket depth will vary slightly for each pocket in the fabric. However, we have found that an average of five measured pocket depths for the structuring fabric provides a good characterization of the pocket depth.

  Although a digital microscope is used in the embodiment described above to determine the pocket depth, other instruments can alternatively be used to determine the pocket depth by the techniques described herein. Can be used to determine. For example, in other embodiments, a laser profilometer (or “laser profiler”) may be used to determine the pocket depth, similar to the digital microscope described above. The laser profiler is able to determine the depth profile of the pocket, and the depth profile generated using a digital microscope, as explained above, is the pocket depth profile. Can be used to determine the pocket depth in the same way that it is used to determine. Examples of such laser profilers are Leicester, United kingdom, Taylor Hobson, Ltd. Is a TALYSURF® CLI high resolution 3D surface profiling system manufactured by In still other embodiments, an in-line laser profile measurement device (“laser line scanner”) is used to determine the pocket depth of the fabric by the techniques described herein. An example of such a laser line scanner is the LJ-V7000 series high-speed inline profile inspection device manufactured by Keyence Corporation.

  When using a laser profiler or laser line scanner, the same steps described above in connection with a digital microscope can be used to determine the pocket depth. That is, as shown in FIG. 9, the knuckles and pockets are determined based on a representation of the surface of the structuring fabric. The laser profiler or laser line scanner is then set to determine the depth profile across the pocket from one knuckle to another, ie, the laser profiler or laser line scanner is as shown by line PL in FIG. Scan across the line being oriented. From this measured profile, the pocket depth can be determined in a manner similar to that method described above in connection with FIG. Various analysis software programs can be used to perform analysis of depth profiles measured by a laser profiler or laser scanner. One example is surface weighing software provided by TrueGage of North Huntingdon, Pennsylvania.

  Each of the alternative depth measuring instruments, i.e., digital microscope, laser profiler, or laser line scanner, can provide certain advantages. For example, a digital microscope can provide a highly accurate measurement of pocket depth. On the other hand, a laser profiler is generally an instrument that is easy to work with, thereby providing a quick measurement of pocket depth. As another example, laser line scanners quickly collect large volumes of data and thus have the ability to measure many depth profiles in a short period of time. In this regard, embodiments of the present invention include using a laser line scanner to determine a pocket depth profile of a structuring fabric running over a paper machine. In this embodiment, the laser line scanner is positioned adjacent to the structuring fabric on the machine, and the laser line scanner measures the pocket depth profile as the fabric advances through the scanner. As will be appreciated by those skilled in the art, the structuring fabric in a papermaking machine can travel at speeds faster than 3,000 feet per minute (914.4 m / min). However, laser line scanners such as the LJ-V7000 series inspection system described above by Keyence Corporation have the ability to measure several thousand depth profiles per second. Therefore, the laser line scanner has the ability to measure the pocket depth in the rapidly moving structuring fabric so that the structuring fabric is in actual use on the paper machine. Provide highly useful pocket depth data.

  Note that regardless of the measurement instrument and technique used to determine the pocket depth, the measured pocket depth will vary slightly from pocket to pocket in the fabric. Generally speaking, it has been found that an average of the five measured pocket depths for the structuring fabric provides a good characterization of the pocket depth. Of course, more or fewer measurements may be made, for example, to determine the average pocket depth, depending on the level of accuracy desired in the measurement.

  In the pocket depth determination technique described above, the structuring fabric itself is used to determine the pocket depth. In some cases, it may be easier to form a representation of the fabric and then determine the pocket depth from that representation. For example, a representation of the fabric knuckle and pocket structure can be formed by pressing the contact surface of the fabric against wax paper, as also described above. The wax representation of the fabric can then be scanned using one of the techniques described above. For example, a laser line scanner can be used to determine the depth in the wax print between knuckles in the wax print.

  The effective volume of the structuring fabric pocket is an important property of the structuring fabric, which can be easily determined once the pocket size is calculated according to one of the techniques described above. Will be understood by those skilled in the art. The effective volume of the pocket multiplies the cross-sectional area of the pocket at the surface of the structuring fabric (ie, between the knuckle surfaces) by the depth of the pocket where cellulosic fibers in the web can migrate during the papermaking process. Product. The cross-sectional area of the pocket is the same as the pocket area (PA) estimate as described in Table 1 or Table 2 above. Thus, the effective pocket volume can be simply calculated as the product of the pocket area estimate and the measured pocket depth.

  Another important property of a structuring fabric can be defined as a planar volumetric index for the fabric. Generally speaking, the flexibility, absorbency, and caliper of a paper product made using the fabric depends on the contact area of the fabric, i.e., the knuckle surface of the fabric that the web contacts in the papermaking process. May be affected by the area formed. Further, the flexibility, absorbency, and thickness of paper products can be affected by the size of the pockets in the fabric. The planar volume index is the contact area ratio (CAR) (as described in Table 1 or Table 2 above) multiplied by the effective pocket volume (EPV) and multiplied by 100, ie CAR Since it is calculated as * EPV * 100, the planar volume index provides an indication of contact area and pocket size. The contact area ratio and effective pocket volume can be calculated using the techniques described above, after which a planar volume index for the fabric can be easily calculated.

  As will be appreciated by those skilled in the art, knowing the properties of the fabric knuckles and pockets, such as the size and density of the knuckles and pockets, provides a deep understanding of the fabric. One example of an application that uses properties involves developing a correlation between specific contact surface properties and the resulting paper product. By correlation, additional fabric configurations can be developed and those configurations can be characterized without testing the full scale fabric on a paper machine. Thus, the techniques described above for determining the contact surface characteristics of a fabric can save time and resources for both fabric manufacturers and / or papermakers trying different fabrics. .

  The techniques described above can also be used in a method of analyzing wear on a papermaking fabric. In one such method, a first representation of a knuckle in a portion of the fabric is formed in the media. This first representation can be a print on the pressure measurement film, or the representation can be a photograph of a portion of the fabric and can be stored in the camera. A first image of the fabric knuckle is generated based on the first representation, for example, by scanning a pressure measurement film or by downloading a photo from a camera. From the generated image, at least one characteristic relating to the contact area of the fabric can be determined as described above. The fabric can then be subject to wear. If the fabric is mounted on a paper machine, wear can easily occur by operating the paper machine. Alternatively, wear simulation can be performed on the fabric by sanding or polishing.

  After the fabric is worn, the process of obtaining an image of a portion of the fabric and determining contact surface properties is performed again. That is, a second representation of a knuckle in a portion of the fabric is formed in the media, which is used to generate a second image, which determines the surface characteristics of the film. Is analyzed. In this respect, the second representation may or may not be taken from the same fabric portion as the first representation. It will be expected that the knuckles in the fabric will increase in size as a result of wear. In addition, new knuckles can be formed in the fabric. As part of the contact surface characterization, the knuckle size increase can be quantified by comparing the analysis of the second image after wear with the analysis of the first image before wear. The process of wearing the fabric and subsequently determining the contact surface properties can be repeated any number of times and with any given amount of wear during each analysis.

  A further part of analyzing wear on the fabric involves correlating paper products made using the fabric with changes in contact surface due to wear. For example, a paper product is formed using the fabric before the first representation of the fabric is taken. The properties of the paper product, such as the size of the dome in the product or the thickness of the product, then correlate with the contact surface characteristics determined through analysis of the first image formed by the first representation. Be made. A second paper product is then formed using the fabric after the fabric has undergone wear and before the second representation of the fabric is taken. The properties of the second formed paper product are then correlated with the contact surface characteristics determined through analysis of the second image. Thus, an understanding of how the paper product formed changes as a particular fabric configuration wears can be realized.

  In a further aspect of the invention, the techniques and methods described above can be used to compare different portions of the fabric, especially after the fabric has run over the papermaking machine for a long period of time. It is known that different parts of the fabric will exhibit different wear due to inconsistencies in the track that the fabric follows in the paper machine. According to different embodiments, the surface characterization techniques can be applied to different portions of the fabric, for example, before and after the fabric is run over a papermaking machine. Alternatively, the surface characterization techniques can be applied to different parts of the fabric while the fabric is still mounted on the paper machine. Thus, an understanding of how different parts of the fabric wear in the papermaking machine can be realized.

  According to yet another aspect of the present invention, contact surface characterization can be used to obtain a fabric for making a paper product with a specific three-dimensional structure. Figures 11A and 11B illustrate such a process. FIG. 11A shows an example of an image 800 of a paper product that is analyzed using the techniques described above. In particular, the paper product has a three-dimensional structure, which includes a plurality of domes that are separated by land areas. As explained above, such paper products can be made using a structuring fabric. However, if the specific structuring fabric configuration used to make such a product is not known, the method according to the invention can be used to identify the structuring fabric configuration . As shown in FIG. 11A, the contour 802A can be drawn over the image of the paper product by using an analysis program in the land area of the paper product, which is used to make the paper product. Corresponds to the knuckle position of the structured fabric. Further, a coordinate system that includes guidelines 812 and 814 may be drawn through contour 802A and through locations corresponding to other knuckles. Note that the dome in the paper product corresponds to a pocket in the structuring fabric, so the coordinate system is drawn without passing through the dome.

  After contour 802A is formed and a coordinate system with guidelines 812 and 814 has been drawn, as shown in FIG. Can be matched to the image of the fabric. An example of such a matching is shown in FIG. 11B, in which a coordinate system comprising a contour 802A and guidelines 812 and 814 is overlaid on the fabric image 800A. Note that contour 802A matches the size and shape of the knuckles in the fabric, and the guidelines pass through the knuckles but not through the area corresponding to the pockets in the fabric. This matching indicates that the fabric shown in image 800A can be used to create a paper product similar to that shown in image 800.

  Matching the contour and coordinate system from the paper product to a particular fabric can be facilitated by generating a searchable database of known fabrics. Such a database will include previously determined contact surface characteristics of the fabric, such as knuckle size, location, pocket size, and the like. After determining the size and position of the fabric knuckles and pockets from the contour and coordinate system formed from the paper product, the database can be searched for fabrics with similar knuckles and pocket sizes and positions.

To facilitate the process of matching the analyzed image of the paper product with the fabric, additional parameters developed during the analysis of the paper product can be used. One such additional parameter is the frequency with which one set of guidelines intersects with guidelines from the other set of guidelines. Note that a “set” of guidelines represents parallel guidelines, for example, guideline 812 and all guidelines parallel to it form a set. In FIG. 11A, the frequency of the set of guidelines, including guideline 812, will be calculated, for example, the distance between two of the guidelines that intersect guideline 810 when measured along one guideline 810. Let the analysis program decide. For example, if the guidelines that intersect with the guide lines 810 are measured along the guide lines 810 and are spaced apart by 0.130 cm, the intersecting guidelines are 7.7 cm ⁻¹ (1/0. 130 cm). By measuring the spacing between this set of guidelines along one of the guidelines 812, a similar frequency calculation can be made for the other set of guidelines that intersect with the guides 812. Once determined, the frequency of guideline spacing for paper products can be matched to a previously determined frequency of guideline spacing for fabrics, which has been stored in a searchable database.

  Another parameter that can be calculated to facilitate the process of matching knuckles and guidelines outlined from the paper product to a particular fabric is the angle to the set guidelines from the reference line. For example, the scale line SC in FIG. 11A can be used as a reference, and the angle α can be determined between the scale line SC and one set of guidelines. The angle from the scale line SC to the other set of guidelines can also be determined. Once determined, the angle from the paper product reference to the guideline set can be matched to the previously determined angle from the fabric reference to the guideline set, and the previously determined angle is searchable. It has been stored in a simple database.

  While the method described above has been described in terms of matching a paper product to a known fabric, other embodiments can be used over a three-dimensional paper structure that is desired but not yet created. It will be readily understood to include selecting a known fabric that has been made. That is, one or more contour knuckles can be generated in the blank image, and knuckles and pocket patterns can be generated by drawing guidelines in the blank image. The generated image can then be matched to a known fabric as described above.

  In yet another embodiment, the fabric may be designed and manufactured based on analysis of paper product images or based on generated images representing knuckle and pocket configurations. In this method, the warp and weft are selected to correspond to the desired knuckle and pocket configuration, as determined by analysis of the paper product image, or as generated in the blank image. Techniques for creating fabrics with specific weft and weft weaves are well known in the art. Thus, a fabric can be created with a chosen warp and weft configuration.

  In other embodiments of the present invention, the fabric characterization techniques described herein are used to modify the configuration of the first papermaking fabric to create a new second papermaking fabric having different characteristics. It is possible. In these embodiments, at least one knuckle or pocket characteristic of the first papermaking fabric is determined by the techniques described above. The characteristic can be, for example, one or more of the characteristics described in Table 1 or Table 2 above. Further, the characteristic can be pocket depth or effective pocket volume, which is determined according to the techniques described above. Based on the determined characteristics, a modified fabric design is generated and the characteristics are changed. For example, the pocket depth can be increased from the pocket depth measured in the first papermaking fabric. Those skilled in the art will understand the factors that determine the properties of the papermaking fabric, and therefore how the design of the first papermaking fabric can be modified to create a new papermaking fabric with different properties. You will understand what you get. For example, aspects of the fabric such as yarn diameter, yarn density, yarn shape, weave, and one or more of the thermal settings used to bind the yarns together are modified properties Can be modified to create a second papermaking fabric having: One of many examples of papermaking fabric manufacturing techniques that utilize some of these factors can be found in US Pat. No. 6,350,336, the disclosure of which is in its entirety Incorporated by reference.

  In addition to or in conjunction with embodiments for modifying the configuration of papermaking fabric designs, the properties of paper products made using structuring fabric can be used in the development of papermaking fabrics with specific properties . For example, the characteristics of the first papermaking fabric can be determined using the techniques described above. The first papermaking fabric can also be used to make a papermaking product using, for example, the papermaking methods described above. The properties of the paper product can then be determined and subsequently correlated with the determined properties of the first papermaking fabric. For example, the density and height of a dome formed in a paper product can be measured by examining the dome with a microscope. As discussed above, the dome is formed in the pocket of the papermaking fabric. Thus, the pocket density and pocket depth determined in the papermaking fabric can be correlated to the dome density and dome height found in paper products made using the papermaking fabric. Such correlations can then be used to determine what paper products can be expected to be made by another papermaking fabric having comparable properties. In addition, as described above, new papermaking fabric designs with adjusted properties can be developed to create paper products with modified properties as needed.

Although the present invention has been described in certain specific exemplary embodiments, many additional modifications and variations will be apparent to those skilled in the art in view of the present disclosure. Accordingly, it should be understood that the invention may be practiced otherwise than as specifically described. Accordingly, it should be considered that the exemplary embodiments of the present invention are illustrative and not restrictive in all respects, and the scope of the present invention is defined by the foregoing description. Rather, it should be determined by any claims that can be supported by this application and their equivalents.

Claims (10)

A method for determining the characteristics of a fabric, comprising:
Forming a representation of a portion of the surface of the fabric, the representation indicating the location and size of knuckles and pockets in the surface of the fabric;
Generating an image of the portion of the surface of the fabric based on the representation;
Displaying at least a portion of the image on a screen associated with a computer having a processor;
Delineating around at least one of the knuckles in the displayed image;
Drawing a guideline in the displayed image, wherein the guideline passes through (i) the center of the outlined knuckle, (ii) passes through another knuckle, and (iii) the pocket Drawing to form a shape surrounding a region of the image corresponding to a location formed between the knuckles;
The method wherein the contours and guidelines are drawn using an image analysis program stored in a non-transitory computer readable medium. The method of claim 1, wherein a length of the outlined knuckle, a width of the outlined knuckle, and an orientation angle of the guideline, and of the knuckle along the guideline. Further comprising determining at least one of the locations;
The method according to claim 1, wherein the determination is performed by the image analysis program.   3. The method of claim 2, wherein the quadrangular shape is a non-rectangular parallelogram. The method of claim 3, further comprising calculating at least one of a percentage of the surface of the fabric corresponding to the knuckle and a density of the pockets;
The calculation includes the length of the outlined knuckle, the width of the outlined knuckle, the orientation angle of the guideline, the location of the knuckle along the guideline, and the parallelogram Using the determination of the calculated area of at least one of the methods.   5. The method according to claim 4, wherein the area of the parallelogram is an angle of one corner of the parallelogram and two parallel guide lines of the guide line forming the parallelogram. A method characterized in that it is calculated using the distance between.   2. The method of claim 1, wherein the representation comprises (i) pressing the fabric against a pressure measuring film, (ii) taking a picture of the fabric, and (iii) A method characterized in that it is formed by one of pressing against wax paper. A method for determining the characteristics of a fabric, comprising:
Forming a representation of a portion of the surface of the fabric, wherein the representation indicates the location and size of knuckles and pockets in the surface of the fabric, the representation comprising a print of the fabric surface; And one of the photographs of the surface of the fabric, and
Generating an image of the portion of the surface of the fabric based on the representation;
Displaying at least a portion of the image on a screen associated with a computer having a processor;
Determining the size and location of the knuckle within the representation of the representation;
Determining the size and location of the pockets in the representation of the representation;
Drawing a unit cell in the displayed image for the portion of the surface of the fabric, the unit cell being defined by a guideline, the guideline comprising: (i) a center of the knuckle; Passing through (ii) forming a shape surrounding a region of the image corresponding to where the pockets are formed between the knuckles;
Calculating at least one property of the surface of the fabric based on the property of the unit cell formed by the guidelines;
The method wherein the contours and guidelines are drawn using an image analysis program stored in a non-transitory computer readable medium.   The method of claim 7, wherein the shape is a non-rectangular parallelogram. 9. The method of claim 8, wherein the calculating step further includes calculating at least one of a percentage of the surface of the fabric corresponding to the knuckle and a density of the pockets;
The method uses the size of the knuckle along the guideline and the area of the parallelogram. 10. The method of claim 9, wherein the area of the parallelogram is an angle of one corner of the parallelogram and two parallel guide lines of the guide line forming the parallelogram. A method characterized in that it is calculated using the distance between.