Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
2000-04-06
2003-05-06
Lorengo, J. A. (Department: 1734)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S264000, C156S350000, C156S354000, C428S074000, C428S079000, C428S095000, C428S195100, C116S200000, C604S361000, C604S385030, C604S389000
Reexamination Certificate
active
06558499
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to disposable absorbent articles, and more particularly to disposable absorbent articles having graphics thereon, and processes for making the same.
BACKGROUND OF THE INVENTION
Traditionally, disposable absorbent articles, such as infant diapers or training pants, adult incontinence products and other such products, are constructed with a moisture-impervious outer backing sheet (or “backsheet”), a moisture-pervious body-contacting inner liner sheet (or “topsheet”), and a moisture-absorbent core (or “absorbent core”) sandwiched between the liner sheet and the backing sheets. These disposable absorbent articles oftentimes include additional features such as elastic waist bands, elastic leg bands, and stretchable side panels. Further, decorative graphics can be incorporated into the disposable absorbent article for aesthetic and functional purposes.
Disposable absorbent articles are generally assembled on an automated production line by separately supplying the individual components of the absorbent article to the production line at predetermined locations along the machine direction, and layering the individual components to form an integrated absorbent article. Various methods are available for bringing these individual components together so that the components in the integrated product are in a desired relation with respect to each other. In bringing these individual components together, various known methods have been used to sense the position of a particular component, and then to adjust the placement of subsequent components in order to properly position them with respect to the previously sensed component.
Prior art methods for assembling components of absorbent articles have employed photo/optical techniques to sense reference markers on the individual components. The reference markers assist in cutting and placing the individual components onto the integrated absorbent article. The reference markers have typically been included in the final assembled product. This is so because the reference markers employed in prior techniques need to be sensed downstream in the production line to provide error correction, requiring complex feed-back control systems. However, the inclusion of the reference markers on the final assembled product can detract from the aesthetics of the product and are therefore not desirable.
For example, U.S. Pat. Nos. 5,286,543 and 5,235,515 to Ungpiyakul et al. disclose a system for selectively providing predetermined segments of web material to an absorbent article production line using a reference marker which is incorporated into the final assembled absorbent article. Generally stated, the method includes the steps of supplying the web material at a web speed and sensing a reference mark on the web material to generate at least one reference mark datum which is associated with a selected web segment. A separation datum is provided and the web material is divided along a separation region during production of the web segment. A relative phasing between the sensing of the reference marker and the dividing of the web material is controlled. The phase control is conducted with respect to a set reference value. The web segment is placed onto a substrate, and a location of the separation region relative to the reference mark is separately detected to generate at least one location datum. The location datum is evaluated to generate an updated set reference value, and the phase controlling step is adjusted to incorporate the updated set reference value.
The '543 Patent discloses that the predetermined segments of web material comprise discrete graphic patches corresponding to the tape landing zone of the diaper. The patch is said to have a predetermined set of graphics which are “congruously entire.” The patches are also said to abruptly change from graphics set to graphics set and, therefore, from diaper to diaper because there is no modulating transition between the adjacent compositions formed on the original supply roll of web material. The patches are said to be provided with reference markers delineating the boundaries between individual web or patch segments. The reference markers comprise any signaling mechanism which is recognizable by a machine.
During the production of the absorbent article according to the '543 Patent, a first sensing means detects the reference marker associated with the graphic as the web containing the graphics is unwound. Then, at a remote position in the manufacturing process, a second sensor observes the portions of the reference markers which remain upon each web segment. If the web segment is not correctly cut, the remote, second sensor detects this improper separation of the graphic. In order to correct for any improper cutting of the web segment, the system in the '543 Patent generates an updated set reference value based on where the second, remote sensor observes the reference marker downstream in the manufacturing line. The system is then selectively adjusted to incorporate the updated set reference value to assure that subsequent relatively smaller patches of web material are properly cut and positioned with respect to the other components forming the absorbent article.
The '543 Patent at col. 14, lines 24-55 admits to be distinguishable from so-called “conventional techniques” employing, for example, a “shift register” scheme, for matching detector information to a particular manufacturing operation, such as the operation of a cutter. The so-called conventional techniques are said not to be capable of withstanding severe process disturbances. These disturbances, described as start-ups, splices within various web materials, and non-uniform stretching of web material caused by a non-uniform winding of the web materials onto the associated supply roll, are said to cause an improper placement of a significant number of patches and thereby increase cost and waste.
To overcome process disturbances, the so-called conventional techniques discussed in the '543 Patent are said to be sensitive to the distance between the sensing means for detecting the reference marker and the cutting mechanism. In other words, the reference marker sensor in the conventional techniques had to be placed relatively closely to the cutting mechanism because, if for example, a detector is mounted a relatively large distance, such as 25 web segment lengths before the cutting unit, the phasing mechanism can phase 25 patches too soon. Where a new roll of material is spliced onto an expiring roll with the sets of patch graphics on the new roll being “out of phase” from the previous roll, up to 25 patches may be cut incorrectly. Furthermore, the '543 Patent states that conventional techniques in which the detector is mounted a large distance from the cutter, the individual sets of print design graphics may not be exactly equally spaced, and the relative position of the patch graphics measured at the detector may not accurately represent the relative position of the patch graphics when the web material reaches the cutting mechanism. Due to this, the '543 Patent recognizes that the greater the distance between the detector and the cutting mechanism, the larger the errors can be.
To eliminate these processing errors in the situation where the sensor and the cutting mechanism are remote from one another, the '543 Patent employs feedback control in a manner where the reference marker (i) is not removed following its initial sensing by the first sensor, and (ii) is applied to the final assembled absorbent article for subsequent reading by the second, remote sensor. Consequently, the reference marker in the '543 Patent, by virtue of being on the final absorbent article, is constructed to provide for a selected separating of discrete graphics. Indeed, without the reference marker on the final absorbent article in the '543 Patent, feedback control is effectively eliminated from the system described in the '543 Patent, and concomitantly process disturba
Pargass Sunita
Vergona Joseph B.
Hunton & Williams
Lorengo J. A.
Paragon Trade Brands, Inc.
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