Patent Application
20140224442
The present invention relates to a method and apparatus for manufacturing coated paper by applying a liquid to a strip-shaped web of paper to form bands on the web.
One example of such coated paper is low ignition propensity wrapping paper for cigarettes.
In recent years, low ignition propensity wrapping paper for cigarettes has come to be widely known, and such wrapping paper has a fire retardant coated on (applied to) predetermined regions thereof. Where a cigarette using the low ignition propensity wrapping paper is lit, spread of fire toward the proximal or mouth end of the cigarette is restrained. Specifically, the low ignition propensity wrapping paper for cigarettes is obtained by applying a fire retardant in liquid form to a strip-shaped web of paper in such a manner that the regions applied with the fire retardant are spaced at predetermined intervals from each other in the longitudinal direction of the web and extend in the width direction of the web (like bands), and then subjecting the web to aftertreatment such as drying.
The low ignition propensity wrapping paper is often required to have bands of the fire retardant arranged at the intervals defined as a standard (hereinafter referred to as design band pitch). For example, where cigarettes to be produced require that the low ignition propensity wrapping paper to be used should have bands complying with the design band pitch, low ignition propensity wrapping paper having bands with an irregular band pitch or in disagreement with the design band pitch is rejected and is not used.
There has been known an apparatus which is configured to inspect the width and spacing of the bands of a fire retardant on the web in the process of manufacture of cigarette wrapping paper (Patent Document 1). Also, a cigarette paper manufacturing machine has been known in which the width of bands formed on the web is inspected by an inspection apparatus to adjust the amount of the fire retardant to be applied to form the bands (Patent Document 2).
Patent Document 1: PCT International Application-Japanese Translation No. 2001-509366
Patent Document 2: Unexamined Japanese Patent Publication No. 2009-148759
In the process of manufacture of the low ignition propensity wrapping paper, however, after the coating liquid is applied to the web to form the bands, a predetermined process such as drying process as stated above (hereinafter referred to as aftertreatment) is performed on the web, so that the web shrinks during the subsequent process. Consequently, the lengthwise dimension of the strip-shaped web varies during the manufacturing process. Also, there are a variety of kinds of webs and fire retardants used for low ignition propensity wrapping paper, and the extent of shrinkage is affected by the kind of the web or fire retardant used.
Since shrinkage of the web occurs under the influence of various factors as stated above, it is difficult to obtain wrapping paper having bands complying with a certain design band pitch.
Neither of the aforementioned Patent Documents 1 and 2 makes mention of the problem of web shrinkage caused during manufacture and consequent difficulty in obtaining low ignition propensity wrapping paper having bands complying with a design band pitch.
The present invention was created in view of the above circumstances, and an object thereof is to provide a coated paper manufacturing method whereby, even if a web shrinks in process of manufacture, coated paper can finally be made to have bands with a band pitch equivalent to a design band pitch, and a coated paper manufacturing apparatus suited for carrying out the manufacturing method.
To achieve the above object, the present invention provides a method of manufacturing coated paper by applying a coating liquid to a strip-shaped web of paper to form a plurality of bands extending in a width direction of the web and spaced from each other in a longitudinal direction of the web, including:
a coating step of applying the coating liquid to the web to form the bands with a coating band pitch narrower than a design band pitch defined as a standard for the coated paper;
an aftertreatment step, executed after the coating step, of drying the web; and
a tension applying step, executed after the aftertreatment step, of expanding a band pitch of the web by applying tension to the web to cause the band pitch of the web to approach the design band pitch.
The aftertreatment step may further include smoothing wrinkles in the web.
In the tension applying step, tension may be applied to the web by a winding device connected to a take-up reel for winding the web thereon.
The coated paper may be low ignition propensity wrapping paper for cigarettes, obtained by applying a fire retardant to the web in the coating step.
In the tension applying step, feedback control may be performed in such a manner that the band pitch of the web subjected to the aftertreatment step is detected, and based on a detection result, tension to be applied to the web is adjusted.
To achieve the above object, the present invention also provides an apparatus for manufacturing coated paper by applying a coating liquid to a strip-shaped web of paper to form a plurality of bands extending in a width direction of the web and spaced from each other in a longitudinal direction of the web, including:
a coater configured to apply the coating liquid to the web to form the bands with a coating band pitch narrower than a design band pitch defined as a standard for the coated paper;
an aftertreatment unit configured to dry the web applied with the coating liquid; and
a tension applier configured to expand a band pitch of the web by applying tension to the web delivered from the aftertreatment unit.
The aftertreatment unit may further include a wrinkle smoothing device configured to smooth wrinkles in the web.
The coater may include a coating device having a gravure roller configured to apply the coating liquid, the gravure roller has an engraved coating region for applying the coating liquid and an unengraved non-coating region alternating with the coating region in a rotating direction of the gravure roller, and the coating band pitch determined by the coating region and the non-coating region is preferably made narrower than the design band pitch by reducing a dimension of the non-coating region.
The coated paper may include low ignition propensity wrapping paper for cigarettes, obtained by applying a fire retardant to the web.
The apparatus may further include: a pitch detector configured to detect the band pitch of the web delivered from the aftertreatment unit; and a controller configured to perform feedback control in such a manner that based on a detection result provided by the pitch detector, the controller determines a tension to be applied to the web by the tension applier.
In the coated paper manufacturing method of the present invention, the coating liquid is applied to the web to form bands with the coating band pitch narrower than the design band pitch, and after the web is subjected to the subsequent aftertreatment step, the tension applying step of applying tension to the web is executed to cause the band pitch of the web to approach the design band pitch, whereby coated paper having bands with a band pitch equivalent to the design band pitch can be obtained.
The coated paper manufacturing apparatus of the present invention includes the tension applier configured to apply tension to the web which has been applied with the coating liquid to form bands with the coating band pitch narrower than the design band pitch defined as the standard for the coated paper and which has been subjected to the aftertreatment, and the controller configured to control the tension applier so that the band pitch of the web may approach the design band pitch defined as the standard for the coated paper, whereby coated paper having bands with a band pitch equivalent to the design band pitch can be manufactured by the apparatus.
In the wrapping paper manufacturing apparatus 1 shown in
A coating device 10 is arranged on an upstream side of the travel path 3 and includes a gravure roller 12 and a pinch roller 13 so arranged as to hold the web W on the travel path 3 therebetween. When the web W passes between the gravure roller 12 and the pinch roller 13, the gravure roller 12 applies a fire retardant in liquid form, as a coating liquid, to one side, that is, one surface of the web W. The fire retardant is applied to the web W at predetermined intervals in a traveling direction of the web W.
Specifically, as seen from the enlarged view of
More specifically, the coating region 12WK and unengraved smooth roller surface region (hereinafter referred to as non-coating region 12NW) are formed alternately on the gravure roller 12 as viewed in the rotating direction RD of the gravure roller 12. For example, each coating region 12WK has a circumferential dimension A, and each non-coating region 12NW has a circumferential dimension B. The sum (A+B) is referred to herein as the band pitch.
In the web W shown in
Immediately after the application of the fire retardant, the band pitch BP is substantially identical with the coating band pitch of the gravure roller 12, but by the time the web is wound as the low ignition propensity wrapping paper P onto the take-up reel 5, the band pitch varies. This will be explained in detail later.
Referring again to
Further, a wrinkle smoothing device 16 is disposed in the travel path 3 at a location downstream of the drying device 14, and the web W passes through the wrinkle smoothing device 16 after being dried. The wrinkle smoothing device 16 to be used is not particularly limited and may be of any desired type insofar as it is capable of removing wrinkles in the web W. For example, the wrinkle smoothing device 16 may be a device which includes a water coating unit, not shown, and a heater roller (e.g. Yankee dryer), not shown, arranged downstream of the water coating unit and configured to rotate while applying tension and heat to the web W, and which is capable of smoothing out wrinkles in the web W. Where the web W is subjected to wrinkle smoothing after being dried in this manner, the web W elongates in the process of wrinkle smoothing. Thus, in cases where the aftertreatment includes wrinkle smoothing, the present invention can be more advantageously applied because there is an additional factor that causes change in design band pitch.
The web W, which is subjected to the aforementioned processes, is made of paper and has a basis weight of, for example, 20 to 70 g/m2; therefore, the web W is liable to elongate and shrink as it is subjected to the processes while traveling along the travel path 3. Thus, even if the band pitch along the traveling direction of the web W is set to a predetermined pitch (e.g. design band pitch) at the time of coating, the band pitch of the web W varies thereafter. It is difficult to predict such variation in the band pitch, and the fact is that the band pitch of the low ignition propensity wrapping paper P (band pitch of the product) wound onto the take-up reel 5 is scarcely in agreement with the design band pitch.
The wrapping paper manufacturing apparatus 1 according to the present invention has a configuration described below so that the low ignition propensity wrapping paper P subjected to the aftertreatment may have a band pitch close to the design band pitch.
In the wrapping paper manufacturing apparatus 1, the coating device 10 (coater) applies the fire retardant to the web W to form the band portions with the coating band pitch narrower than the design band pitch, and a tension applier is provided to apply tension to the web W after the web W is subjected to the aftertreatment in the drying device 14 and the wrinkle smoothing device 16 (aftertreatment units) and before the web W is wound onto the take-up reel 5. A controller (monitoring system 50, described later) is configured to control the tension applier so that the band pitch of the web may become close to the design band pitch.
Referring now to
Preferably, the gravure roller 12 used in the coating device 10 has a coating band pitch shorter by 0.05 to 0.30 mm than the design band pitch, that is, the dimension B of the non-coating region 12NW is decreased by 0.05 to 0.30 mm. the coating band pitch is preferably shorter by about 0.15 mm than the design band pitch.
As shown in
An output signal indicative of the amount of travel (length) of the web W, detected by the length measuring roller 30, is sent to the monitoring system 50 serving as the controller, described later.
A band sensor 35 is arranged downstream of the length measuring roller 30. The band sensor 35 to be used is not particularly limited and may be any desired detecting device insofar as it is capable of detecting the band portions BD of the moving web W. A suitable detecting device known in the art may be employed. For the band sensor 35, a detecting device may be used which includes, for example, a light emitter for radiating infrared light onto the moving web W and a light receiver for receiving the infrared light reflected from the web W. The reflected light received by the light receiver has different intensities depending on whether the infrared light has been reflected by the band portion BD applied with the fire retardant or by the uncoated portion ND. Thus, the band sensor 35 can distinguishably detect the band portion BD and the uncoated portion ND of the moving web W.
The band sensor 35 is configured to start operating in synchronism with the predetermined time for which the length measuring roller 30 measures the length of the web W. As explained above with reference to
The output signal from the band sensor 35 is also sent to the monitoring system 50, and the above process of calculating the band pitch BP is executed by the monitoring system 50. The length measuring roller 30 and the band sensor 35 constitute a pitch detector.
A tension detecting device 37 for detecting the tension acting on the web W may be arranged downstream of the band sensor 35. The tension detecting device 37 may have a configuration in which a roller 38 in contact with the web W is urged by a spring member, not shown, in a predetermined direction (to the right in
The manufacturing apparatus 1 is equipped with a tension applier for increasing the tension of the web W as needed. The tension applier to be used is not particularly limited and may be any desired device insofar as it is capable of appropriately applying tension to the moving web W. For example, a motor 6 for winding the web onto the take-up reel 5 may be used as the tension applier. Specifically, the tension acting on the web W can be increased by increasing the winding tension applied by the motor 6 (increasing the take-up speed of the motor). When the web W is applied with such increased tension, its band pitch expands. Operation of the motor 6 (winding device) is controlled by the monitoring system 50.
Preferably, the manufacturing apparatus 1 is provided with a roll tightness adjusting device 40 for restraining variations in roll tightness of the web W (wrapping paper) wound onto the take-up reel 5. The roll tightness adjusting device 40 includes, as shown in
The wrapping paper manufacturing apparatus 1 includes the monitoring system 50 as stated above. The monitoring system 50, which is, for example, a microcomputer for performing overall control of the manufacturing apparatus, controls the operations of the aforementioned devices including the coating device 10, the drying device 14 and the wrinkle smoothing device 16, and also functions as a controller for controlling the tension acting on the web so that the wrapping paper obtained may have bands with a band pitch equivalent to the design band pitch.
First, the monitoring system 50 executes a coating step (S1). In the coating step, the coating device 10 is operated. Specifically, in this step (S1), the fire retardant (coating liquid) is applied to the web W to form band portions BD (see
Subsequently, the monitoring system 50 executes an aftertreatment step (S2). That is to say, the aftertreatment, which includes the process of drying the web W by means of the drying device 14 and the process of smoothing wrinkles by means of the wrinkle smoothing device 16, is performed after the coating step (S2), to arrange the shape of the web W.
Then, the monitoring system 50 executes a tension applying step (S3). The tension applying step (S3) is a step executed after the aftertreatment step (S2) to expand the band pitch of the web W by applying tension to the web W so that the band pitch BP of the treated web W may become close to the target design band pitch. It is to be noted that the above explanation of the steps is directed to a certain portion of the web W which is sequentially subjected to different processes, and since in practice the web W is continuously treated, the aforementioned steps are concurrently executed for respective different portions of the web W.
Preferably, in the tension applying step (S3), feedback control is performed in such a manner that tension is applied to the web W while detecting the actual band pitch BP of the web W on the basis of the outputs from the length measuring roller 30 and the band sensor 35 (on the basis of the result of detection of the band pitch). Such feedback control enables the applied tension to be suited for the detected state of the web W, whereby the band pitch of the web W can be made to approach the design band pitch.
As described above, the coating band pitch is set to be narrower than the design band pitch, and then under the control of the monitoring system 50, tension is applied to the web W so that the bands of the web W may have a band pitch BP identical with or very close to the design band pitch before the web W, that is, the low ignition propensity wrapping paper, is wound onto the take-up reel 5.
The process illustrated in the flowchart is started at predetermined intervals of time. First, the monitoring system 50 acquires detection signals from the length measuring roller and the band sensor 35 constituting the pitch detector (S31), and calculates an actual band pitch RP of the web W (S32). The band pitch RP is compared with a design band pitch AP defined as the standard band pitch (S33). Based on the comparison result, the monitoring system 50 determines a tension to be applied to the web W.
If the band pitch RP of the web W is equal to the design band pitch AP, then it is unnecessary to adjust the tension; therefore, the monitoring system 50 judges that the current tension should be maintained (S34), and supplies a signal to a tension setting device to maintain the current tension (S38). Consequently, the tension setting device maintains the tension then applied to the web W. The tension setting device corresponds to the motor 6 for applying tension to the web W being wound onto the take-up reel 5, explained above with reference to
If it is judged by the monitoring system 50 that the band pitch RP is smaller than the design band pitch AP (S35), the monitoring system 50 concludes that the tension should be increased (S36), and supplies a signal to the tension setting device to increase the tension (S38). In this case, the tension setting device increases the tension applied to the web W.
Conversely, if it is judged that the band pitch RP is greater than the design band pitch AP (S35), the monitoring system 50 concludes that the tension should be decreased (S37), and supplies a signal to the tension setting device to decrease the tension (S38). In this case, the tension setting device decreases the tension applied to the web W.
In the wrapping paper manufacturing apparatus 1 according to the present invention, the monitoring system 50 performs feedback control by repeatedly executing the process shown in the flowchart of
The wrapping paper manufacturing apparatus 1 shown in
The configuration of the modification on the upstream side of the wrinkle smoothing device 16 is identical with that of the wrapping paper manufacturing apparatus 1 shown in
In
In the example illustrated in
The tension applying roller device 63 arranged downstream of the tension adjusting roller device 61 is associated, for example, with a motor 64 for applying tension to the web W as needed. Namely, the motor 64 performs the function of the aforementioned motor 6 associated with the take-up reel 5, and tension is applied to the web W by increasing the web feed speed of the tension applying roller device 63 relative to the web feed speed of the tension adjusting roller device 61. By varying the relative speed, it is possible to adjust the magnitude of the tension.
The band pitch detecting device 65 may be any desired device insofar as it is capable of detecting the band pitch. For example, the length measuring roller 30 and the band sensor 35 explained above may be used.
Like the foregoing embodiment, a monitoring system (not shown) may be configured to control the tension applying roller device 63 on the basis of the band pitch detected by the band pitch detecting device 65 so that the detected band pitch RP may approach the design band pitch AP. Thus, it is possible to manufacture such low ignition propensity wrapping paper that the pitch of the bands on the web W is identical with or very close to the design band pitch.
In
The present invention is not limited to the foregoing embodiments and may be modified in various ways.
For example, in the above embodiment, the fire retardant is applied as a coating liquid to manufacture low ignition propensity wrapping paper, but the present invention is also applicable to manufacture of other types of coated paper obtained by applying a liquid to a web to form bands.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2012/056564 | Mar 2012 | US |
| Child | 14256256 | US |
