JP2844892B2 - Paper quality measurement device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an apparatus for measuring the quality of paper manufactured by a paper machine or a coating machine, and particularly to a measurement in a split state in which the paper is split into two. About.

<Prior Art> A paper quality measuring apparatus is disclosed in, for example,
-192892. 7A and 7B are explanatory diagrams of a measurement state of the conventional apparatus, wherein FIG. 7A shows a scanning state of the sensor in the paper width direction, and FIG. 7B shows an on-sheet / off-sheet signal. The sensor head 10 scans reciprocally in the width direction of the paper, and distinguishes the scanning direction between forward F and backward B. The on-sheet detection unit 32 uses an optical switch element or the like, and is provided at both left and right (widthwise) ends of the sensor head 10 around a detection end called a sensor target 20. And
When both are on paper, the on-sheet state is set, and when at least one is out of paper, the off-sheet state is set, and it is determined whether or not the sheet is on paper.

<Problems to be Solved by the Invention> Under normal operating conditions, the paper is uniformly distributed in the width direction, so that the conventional apparatus can sufficiently determine on-sheet / off-sheet. However, in order to increase the strength of the paper with kraft paper or the like, the paper is sometimes split into two pieces. The state in which the paper is split into two is called a split state. 8A and 8B are diagrams for explaining measurement in a split state. FIG. 8A shows a scanning state of the sensor in the paper width direction, and FIG. 8B shows an on-sheet / off-sheet signal. Assuming that the width of the on-sheet detection unit 32 in the sensor head 10 is d and the width of the split is W, d> W
In this case, a pseudo on-seat state occurs. That is, when the sensor head 10 passes through the split, the on-sheet detection unit 32
Exists on the separated paper on both sides to generate an on-sheet signal. However, since the sensor target 20 is actually located above the split, the measurement is being performed in a place where no paper exists.

FIG. 9 is an explanatory diagram of a paper quality measurement signal in a pseudo on-sheet state. Regarding the values displayed in the paper width direction, such as the basis weight and the water content, the measured values in the portion where the paper actually exists and the measured values in the pseudo on-sheet state where the air layer is simply measured (on-sheet ghost) ). This deviation causes a sudden change in the measured value before and after the split exists, which adversely affects the control of the paper machine.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to provide a paper quality measuring device that recognizes a position of a split and accurately displays a paper quality measured value.

<Means for Solving the Problems> To achieve the above object, the present invention provides a sensor head that advances / retreats in the paper width direction, a sensor target mounted on the sensor head for measuring paper quality, and the sensor target. An on-sheet detecting portion provided at both ends of the sensor target at an interval (LOF) slightly larger than the size of the sensor target, and an end portion of the sensor target in front of the on-sheet detecting portion when the sensor head is moving forward. And a retreat-side paper end detection unit provided at a sensor target end in the movement direction ahead of the on-sheet detection unit when the sensor head is retreating. ing.

Also, as a signal processing system, a paper end processing unit for providing a detection signal of a forward paper end detection unit when the sensor head is moving forward, a detection signal of a backward paper end detection unit when the sensor head is moving backward, When the on-sheet detecting unit changes the on-sheet state from the on-paper state to the on-sheet state while traveling in the same direction, the split processing unit recognizes that this sensor target is measuring on the split. Is provided.

When the split processing unit determines that the signal is on the split, the signal measured by the sensor target is invalidated.

<Operation> Each component of the present invention performs the following operation. The sensor head includes an on-sheet detection unit that detects whether the sensor target is on the paper, and an advance / retreat-side paper end detection unit that detects the paper end prior to the on-sheet detection unit according to the traveling direction of the sensor. It is installed. The split processing unit invalidates the measurement signal of the sensor target on the split when the signal corresponding to the split is detected by the forward / reverse-side paper end detecting unit.

<Example> Hereinafter, the present invention will be described with reference to the drawings.

FIG. 1 is a configuration block diagram showing one embodiment of the present invention. In the figure, a sensor target is
20 and detectors 32 to 36 are mounted, and a motor 42 reciprocates the sensor head 10 forward and backward in the paper width direction according to a drive signal of a drive circuit 40.

FIG. 2 is a detailed view of the sensor head 10. The on-sheet detection units 32a and 32b use, for example, photodetectors, and have a slightly larger interval (LO) than the diameter φ of the sensor target 20.
F). When the sensor head 10 is moving forward, the advance-side paper end detection unit 34 is provided at the end of the sensor target 20 ahead of the on-sheet detection unit 32, and the distance from the sensor target center is LGHF. Has become. The reverse paper end detection unit 36 is provided at the end of the sensor target 20 ahead of the sheet detection unit 32 in the movement direction when the sensor head 10 is retreating, and the distance from the sensor target center is LGHB. Has become. The forward-side paper edge detection unit 34 and the backward-side paper edge detection unit 36 may use a detection element equivalent to the on-sheet detection unit 32 described above.

Referring back to FIG. 1, the signal processing system will be described. The paper edge processing unit 52 selects the forward paper edge detector 34 when the sensor head 10 is moving forward, and selects the reverse paper edge detector 36 when the sensor head 10 is moving backward, and uses it as a detection signal. . The split processing unit 54 determines whether the sheet is above the split or the end of the sheet. When the sensor head 10 changes from the above-paper state to the above-paper state from the above-paper state while traveling in the same direction, it is recognized that the sheet is in the split state. When the on-seat detecting unit 32 is also in the on-seat state, it is recognized that the sensor target 20 is measuring on the split. The sensor signal processing unit 56 transmits a signal measured by the sensor target 20 to the outside,
When the split processing unit 54 recognizes that the signal is on the split, the measurement signal of the corresponding portion is invalidated.

3A and 3B are explanatory diagrams of the operation of the apparatus shown in FIG. 1, wherein FIG. 3A shows a traveling locus of a sensor target, and FIG.
(C) is an output signal of the forward paper end detection unit 34. The paper exists on both sides of the split,
The sensor target is running zigzag with respect to the paper, where F represents forward movement and B represents backward movement. Advance side paper end detector 34
Is the trailing edge of the strip on the first paper falling out of the paper
The SPLB is detected, and the front end SPLF of the strip is detected when rising from outside the paper onto the paper. The part included in the section SPLB-SPLF in the on-sheet signal of the on-sheet detection unit 32 is invalidated. It is preferable that the detection signal of the advance-side paper end detection unit 34 is corrected to a value corresponding to the interval between the advance-side paper end detection unit 34 and the sensor target 20 to set the split position at the sensor target 20 position.

FIG. 4 is a detailed view of a switch signal of a forward-side paper end detecting unit at the time of forward movement near the split. The sensor head 10 has a structure in which one pulse is generated every 5 mm, for example, as the vehicle travels, and the measurement position is transmitted to the outside together with the measurement value so that the sensor signal can be grasped. The split position is given by the following equation.

SPLB = head position + LGHF-2 PULS SPLH = head position + LGHF-PULS Here, PULS is a distance for one pulse. In the split rear end SPLB, the falling edge is detected, but actually the position of the split rear end is two pulses before. In the front end of the strip SPLF, a rise is detected, but actually the position one pulse before is located at the front end of the strip.

The backward movement of the sensor head 10 is performed in the same manner as the forward movement by using the backward paper end detection unit 36. The split position is given by the following equation.

SPLB = head position−LGHB + PULS SPLH = head position−LGHB + 2PULS FIG. 5 is a block diagram showing the configuration of an example in which the present invention is applied to a profile display device of a paper machine. In the figure, a sensor head 10 includes, for example, an upper head 12 having a β-ray source,
It comprises a lower head 14 on which a sensor target 20 for obtaining the basis weight of paper from the amount of line attenuation is mounted. The optical switch unit 30 includes the above-described on-sheet detecting unit 32, the forward-side paper end detecting unit 34, and the backward-side paper end detecting unit 36. The head drive control unit 50
It has the functions of the paper end processing unit 52 and the split processing unit 54 described above, and sends a drive control signal to the motor drive circuit 40. According to this drive control signal, the motor drive circuit 40
Scans the upper head 12 and the lower head 14 via the motor 42. The motor 42 has a built-in encoder, and obtains the movement position of the upper head 12 and the lower head 14. The head drive control unit 50 receives a head position signal from the motor 42 and an optical switch unit.
An on-sheet signal and a paper edge detection signal are input from 30 and a measurement value signal is input from the sensor target 20, and this measurement value signal is used as a measurement raw signal together with a head position signal as a sensor signal arithmetic unit
Output to The sensor signal calculation device 60 generates width direction data (called a profile signal) by combining the signals sent from the head drive control unit 50. The profile display device 70 receives the width direction data from the sensor signal calculation device 60, receives the split signal from the head drive control unit 50, and displays the profile signal. 6A and 6B are diagrams for explaining the operation of the apparatus shown in FIG. 5, wherein FIG.
(C) shows a region to be masked by the split processing unit 54, and (D) shows a profile displayed by the profile display device 70. The on-seat ghost caused by the split is invalidated by the split signal,
In the profile display device 70, a genuine profile with no measurement value displayed at the split position appears.

In the above embodiment, the case where a single split is used has been described as an example. However, the present invention is not limited to this case. .

<Effects of the Invention> As described above, according to the present invention, the following practical effects are obtained.

Since the split position is detected by the split processing unit 54 for each scan, even if the position or width of the split dynamically fluctuates, it follows accurately.

Since the measurement data of the on-seat ghost can be invalidated by the split signal output from the split processing unit 54, a correct profile display can be performed, and an accurate operation can be performed even when performing the profile control, thereby reducing waste paper.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG.
FIG. 3 is a detailed view of the sensor head 10, FIG. 3 is an explanatory view of the operation of the apparatus shown in FIG. 1, FIG. 4 is a detailed view of a switch signal of a forward-side paper end detecting unit at the time of forward movement near the split, and FIG. FIG. 6 is a block diagram showing the configuration of an example in which the present invention is applied to a profile display device of a machine, and FIG. 6 is a diagram for explaining the operation of the device shown in FIG. FIG. 7 is an explanatory view of a measurement state of the conventional apparatus, FIG. 8 is a view for explaining measurement in a split state, and FIG. 9 is an explanatory view of a paper quality measurement signal in a pseudo on-sheet state. 10 ... Sensor head, 20 ... Sensor target, 32 ...
On-sheet detecting section, 34: forward side paper end detecting section, 36: backward side paper end detecting section, 52 ... paper end processing section, 54 ... split processing section.

Claims (1)

(57) [Claims] 1. A sensor head for moving forward / backward in the paper width direction, a sensor target mounted on the sensor head for measuring paper quality, and a gap slightly larger than the size of the sensor target at both ends of the sensor target. An on-sheet detecting unit provided at the LOF), an advance-side paper end detecting unit provided at an end of a sensor target ahead of the on-sheet detecting unit when the sensor head is moving forward, and the sensor head When the sensor head is moving backward, a retreating-side paper end detecting unit provided at the end of the sensor target ahead of the on-sheet detecting unit in the moving direction; A paper end processing unit that gives a detection signal of a retreat side paper end detection unit when the paper is retracted; and a paper end processing unit that travels in the same direction from the paper state to the paper outside state. State, and when the on-sheet detection unit is in the on-sheet state, a split processing unit that recognizes that the sensor target is measuring on the split, and that the sensor target is on the split by the split processing unit A paper quality measuring device, wherein when it is recognized, a signal measured by the sensor target is invalidated.