JPH01245876A - Method and apparatus for detecting coating state of roll coater - Google Patents

Abstract

PURPOSE:To indirectly detect the present coating state of a roll coater by calculating the coating amount/a unit area on a web from the detected running speed of the web and the consumption speed of a coating agent. CONSTITUTION:A pan 6 is filled with a coating agent 5 by a supply pump 10 and the liquid level C of the coating agent is set to a predetermined level D with respect to a gravure roll 2. Next, when a switch of detection-ON is closed, the supply of the coating agent is stopped and, at the same time, the initial wt. M1 of the coating agent 5 containing the pan 6 is calculated by a load cell 12 to be stored in a display part 16 and, continuously, the wt. M2 of said coating agent 5 after the elapse of T-sec is measured. The running speed S1 of a web 4 can be calculated on the way of the feed of the web 4 or from the rotational speed of a gravure roll 2 or that of a backup roll 3. As a result, when the width 4 of the web 4 is set to W, the coating amount M of the coating agent applied per the unit area of the web 4 can be calculated by formula (1).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for detecting the state of coating of a coating agent on a web in various roll coaters including those for printing.

[Conventional technology]

The coating amount on the web in such a roll coater is determined by the non-nip pressure of the impression cylinder (rubber roll) with respect to the coating roll, the angle of the doctor blade, the degree of adjustment of the coating agent viscosity, etc. In particular, when the application roll is a gravure roll, it depends on the shape, depth, and size of the recesses (cells) on the nine circumferential surfaces.

However, the amount of coating agent per unit area applied to the web changes over time due to various factors even after 311 adjustment.

For example, with gravure rolls, long-term use can cause wear on the peripheral surface and clogging of the coating agent in the cells.

The coating amount gradually decreases below the set value. In such a case, the gravure roll must be repaired or replaced.

[Problem to be solved by the invention]

However, at present, there is no way to numerically determine the actual amount of coating applied to the web during operation, and the only way to do so is by visual inspection or by looking at the coated web.

As a result, the timing for repairing or replacing the gravure roll was missed, resulting in a large amount of coated web being discarded due to poor coating. Another disadvantage was that the amount of coating agent used could not be strictly controlled.

As a result of research into the above-mentioned problem from this perspective, the present inventor has found that by knowing the change in coating agent consumption per unit time, changes in the coating amount per unit area on the web can be detected. In addition to this, we also discovered that the current coating status in the roll coater can be easily determined from changes in the coating amount.

The present invention has been made based on the above findings, and includes:
It is an object of the present invention to provide a method that makes it possible to indirectly detect the current coating state in a roll coater. With this, for example, it is possible to immediately know when to repair or replace a coating roll (gravure roll).

Another object of the present invention is to maintain uniform coating quality while
An object of the present invention is to provide a method that allows the consumption rate of a coating agent to be easily detected.

Still another object of the present invention is to provide an apparatus suitable for carrying out the above method.

[Means to solve the problem]

FIG. 1 shows the principle of the present invention, in which the traveling speed Sl of the web 4 and the consumption speed s2 of the coating agent 5 are detected, and the amount of coating per unit area on the web 4 is calculated based on the detected speeds. The amount of work M can be calculated.

Here, as a detection method for the consumption rate S2 of the coating agent 5, in the case of a gravure coater in which the gravure roll 2 is immersed in the coating agent 5 in the pan 6, the coating agent 5 is supplied to the pan 6. It can be determined by measuring the weight of the coating agent 5 including the pan 6 at regular intervals and calculating the difference in weight.

Further, the detection device according to the present invention has a running speed S of the web 4.
1, a means for detecting the consumption rate S2 of the coating agent 5, and a calculation means for calculating the coating NM per unit area on the web 4 by using the detection value from the 1-car detection means as a human signal. , and display means for displaying a display corresponding to the value calculated by the calculation means.

[Effect]

The coating amount M (g/n?) of the coating agent 5 on the web 4 can be determined by S2/Sl, assuming that the width of the web 4 is the unit length. Since it changes in response to coating conditions such as state, the overall coating state can be detected.

〔Example〕

The drawings show an example in which the present invention is implemented in a direct gravure coater. Needless to say, even if the same gravure coater is used, the same method can be applied to an offset gravure coater or an electrostatic gravure coater.

In FIG. 2, the gravure coater rotates with a gravure roll 2 provided with cells I on its circumferential surface and a backup roll 3 provided with rubber or the like on one circumferential surface in pressure contact with each other at a predetermined nip pressure. The web 4 passes between 2 and 3. The lower part 7 of the gravure roll 2 is immersed in the coating agent 5 in the pan 6.

The coating agent 5 is supplied to the pan 6 through a supply pump 10. A support stand 13 is disposed on the lower surface 11 of the pan 6 via a load cell 12.

The load cell 12 is located between the pan 6 and the support stand 13.

It generates an electrical signal B corresponding to the load, and this signal B is input to the display section 16 and converted to calculate the total weight of the coating agent 5 and the pan 6.

Digital display with numbers or analog display with pointers is provided.

When detecting the coating state, use the lifting means not shown in Figure 2 to raise and lower the support base 1.
3 is set at a predetermined position, the pan 6 is filled with the coating agent 5 using the supply pump 10, and the liquid level C is set at a predetermined level D with respect to the gravure roll 2.

Next, when the detection switch is turned on at the beginning of operation or, in many cases, during operation, the supply of the coating agent 5 into the pan 6 by the supply pump 10 is stopped at the same time.

Hats Tomoshige iM of coating agent 5 including pan 6 with load cell 12
+ [g) is determined on the display unit 16 and stored. Then, the weight MzCg] after T seconds has elapsed is also measured using the load cell 12.

The running speed S + (m /4,60) of the web 4 can be determined from the rotation speed of the gravure roll 2 or backup roll 3 during web feeding or the like.
When the width of the web 4 is W (m), the coating amount of the coating agent 5 applied per unit area of the web 4 is MM Cg/m
) can be determined using a linear equation.

The coating amount M described above changes depending on the wear condition of the gravure roll 2 or the degree of cell clogging, etc.
Measure this value at predetermined intervals.

By examining changes in a constant value, it is possible to detect abnormalities during coating with a gravure coater. Furthermore, the amount of consumption of the coating agent 5 for 10 units or one day can be determined arbitrarily.

[Another example]

FIG. 3 shows another embodiment of the present invention, in which the coating agent 5 in the pan 6 is circulated by a circulation pump 10 to prevent solidification of the coating agent 5 and improve the quality of the coating agent. can be maintained constant.

That is, a circulation system is constructed in which the coating agent 5 is circulated from the lower part of the pan 6 to the upper part of the pan 6 via the intermediate circulation tank 20, and this circulation system and the weight of the coating agent 5 including the pan 6 are Measurement is always possible using the load cell 12. On the other hand, the coating agent 5 can be replenished from the replenishment tank 21 to the tank 20 by the replenishment pump 22 in an amount equal to the consumed amount. In this case as well, the circulation pump 10 is stopped for a predetermined time T, and the load cell 12 detects the difference in weight, that is, the actual consumption amount of the coating agent 5. Then, the consumption rate S2 of the coating agent 5 can be detected by integrating the detected value in the data geography section 22 using a microprocessor.

Furthermore, the running speed S1 of the web 4 is determined by detecting the rotation speed of the gravure roll 2 with a predetermined rotation detector 23.

This detected amount is continuously processed by the data processing unit 24 to calculate the actual amount of coating agent 5 applied to the web 4.

Then, the coating state of the gravure coater is determined from this calculated value, and the result is displayed in text on the display unit 25 equipped with a predetermined display such as a CRT monitor.

[Another embodiment example]

The coating roll 2 of the present invention is not limited to the illustrated gravure roll, but may be a normal roll. The system for supplying the coating agent 5 to the coating roll 2 may be such that the pan 6 is omitted and the coating agent 5 is supplied to the circumferential surface of the roll 2 through a nozzle.

〔Effect of the invention〕

In the present invention, the coating state can be detected by detecting the consumption rate of the coating agent 5 and the running speed of the web 4 and determining the amount of coating agent 5 applied to the web 4. Changes in the overall coating conditions can be easily detected while constantly monitoring the coating state of the web 4 during operation.

In particular, when the coating roll 2 is a gravure roll whose lower part is immersed in the coating agent 5 in the pan 6, coating defects due to abrasion of the roll circumferential surface and clogging of cells can be prevented. It is possible to accurately know when to repair or replace the roll 2. Furthermore, if the weight of the coating agent 5 including the pan 6 is measured at a predetermined time interval T, and the consumption rate of the coating agent 5 is determined from the difference in weight between the measured values, this difference weight is used to calculate the weight of the coating agent 5 applied to the web 4. Since this is the actual consumption amount of the coating agent 5, the detection accuracy can be dramatically improved as a reality.

Furthermore, the above-mentioned coating state is detected by a calculation means.

By making the display means display the corresponding display,
Appropriate displays are automatically displayed depending on the coating condition, so
Even during coating, the amount of coating agent 5 applied to the web 4 per unit area can be numerically determined at any time. Therefore,
It has many advantages, such as the fact that anyone can easily calculate the usage amount of the coating agent 5 in units of 1 day or 10 units.

[Brief explanation of the drawing]

FIG. 1 is a side view illustrating the principle of the present invention. FIG. 2 is a side view showing an example of a gravure coater in which the present invention is implemented. FIG. 3 is a side view showing another embodiment of the invention. 1...Cell. 2...Gravure roll. 3... Bank unroll. 4... Web. 5...Coating agent. 6. ・ ・ ・ ・Bread. 24...Data processing section. 25...Display section. SI: Web running speed. S2: Consumption rate of coating agent. M...Coating amount. Figure 2

Claims (3)

[Claims] (1) In a roll coater that applies coating agent 5 to web 4 via application roll 2, traveling speed S_1 of web 4 and consumption rate S_ of coating agent 5
2 and calculating the coating amount M per unit area on the web 4 from both detected speeds. (2) The coating roll 2 is a gravure roll whose lower part 7 is immersed in the coating agent 5 in the pan 6, and the supply of the coating agent 5 to the pan 6 is cut off for a certain period of time, and the pan 6 is included. 2. The coating state detection method for a roll coater according to claim 1, wherein the weight of the coating agent 5 is measured and the consumption rate S_2 of the coating agent 5 is determined from the weight difference between the measured values. (3) In a roll coater that applies the coating agent 5 to the web 4 via the coating roll 2, means for detecting the running speed S_1 of the web 4 and the coating agent 5
means for detecting the consumption rate S_2 of S_2; a calculation means for inputting the detection values from both the detection means and calculating the coating amount M per unit area on the web 4; and a display corresponding to the calculated value in the calculation means. A coating state detection device for a roll coater, comprising display means for detecting the coating state of a roll coater.