JPH023308A - Printing paper moisture regulator on printing press - Google Patents

Abstract

PURPOSE:To adjust the amount of moisture of printing paper automatically on a printer so as to make it optimum, by comparing a detected amount of moisture with a set amount thereof and by moistening or drying the printing paper on the machine according to the difference of the two values so that the amount of moisture of the printing paper be the set value of moisture. CONSTITUTION:When a deviation signal showing that a detected value of moisture is lower than a set value of moisture is outputted from a comparator 48, a valve control circuit 50 controls a continuously variable valve 52 of a spray moistener 36 to be opened or closed in accordance with the deviation of the two value. This continuously variable valve 52 is supplied with water through a pipe 54 and this water is led to a spray nozzle 38. Besides, the valve control circuit 50 opens an ON-OFF valve 58 for high-pressure air supplied to the spray nozzle 38 through a pipe 56 and an ON-OFF valve 60 for water. Therefore water corresponding to the deviation of the two values is sprayed from the spray nozzle 38. Since an infrared absorption moisture meter 22 of a reflected-light measuring type is employed as a moisture meter, besides, the amount of moisture of printing paper 10 can be detected simply and accurately.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a printing paper moisture regulating device on a printing press, and in particular, it is suitable for use in an offset rotary printing press, and is capable of automatically regulating the moisture content of the printing paper on the printing press, and is suitable for use in an offset rotary printing press. The present invention relates to a printing paper moisture regulating device on a printing press that is capable of maintaining folding durability, tearability, etc.

[Conventional technology]

In offset printing machines, especially web offset printing machines, the ink contains a large amount of solvent, and so-called heat set ink is used, which evaporates and dries the solvent in a hot air dryer to fix the ink on the paper surface. . Therefore, in the dryer, hot air of around 200° C. is blown onto both sides of the printing paper to dry the solvent, but at the same time, a large amount of water is lost from the printing paper. On the other hand, the folding durability, tearability, and other strengths of printing paper vary greatly depending on the amount of water in the paper; as the amount of water increases, the strength increases, and as the amount of moisture decreases, the strength decreases. Therefore, for example, in printing paper consisting of
It has been adjusted to around 6%. However, when paper fibers in the folded area are irreversibly deformed when the paper is folded strongly by a folding machine connected to the printing machine when the moisture content has decreased to around 2% due to hot air drying, etc. , so-called spine cracking (the outside part of the fold appears to be cracked),
Quality accidents such as a decrease in core strength (fastening strength when stapled, threaded, etc. are applied at the folded part) occur. In order to prevent quality accidents like this, in addition to making sure that the dryer does not lose too much moisture, use a spray humidifier to remove moisture from the paper before it is folded in the folding machine and the paper fibers are destroyed. It is necessary to recover it to, for example, 3.5 to 4%. For this reason, conventionally, a printing press operator visually checked the printed matter coming out of the folding machine and adjusted the humidifier depending on whether spine cracking had occurred. However, even if no back cracks are visible from the surface, the strength of the core may be reduced. The core strength cannot be determined unless the fastening strength is actually measured in a laboratory, so there is a problem in that countermeasures such as humidification cannot be immediately taken online. Also, depending on the type of paper, even if spine cracking or reduced core strength is not a problem, if the paper is overdried after printing, moisture in the air may leak from the sides of the book, such as the edges, after binding. The paper may absorb this, causing a phenomenon in which the edges of the paper become wavy (wavy). This also has the problem of not being able to make adjustments to humidification, etc., because it cannot be predicted at the time of printing.

[Problem to be achieved by the invention]

The present invention was made in order to solve the above-mentioned conventional problems, and the paper has sufficient strength before being folded by a folding machine of a printing press, and also has a good moisture content in the end. It is possible to automatically adjust the moisture content of printing paper on the printing machine.
An object of the present invention is to provide a printing paper moisture regulating device on a printing press.

[Means to achieve the task]

The present invention provides a printing paper moisture adjustment device on a printing press, comprising:
On the printing press, a means for detecting the moisture content of the printing paper and a means for setting the target moisture content of the printing paper compare the detected moisture content and the set moisture content, and based on the deviation, determine the moisture content of the printing paper. The above object is achieved by providing means for heating or drying the printing paper on the printing press so that the paper has a preset moisture content. Further, an infrared absorption moisture meter is used as the moisture content detection means.

[Action and effect]

In the present invention, a means (for example, an infrared absorption moisture meter) for detecting the moisture content of printing paper is provided on the printing press, and the moisture content of the printing paper is detected on the printing press by the moisture content detection means. Further, a means for setting a target moisture content of the printing paper is provided, and the target moisture content of the printing paper is set by the moisture content setting means. Furthermore, the moisture content detected by the moisture content detection means and the moisture content set by the moisture content setting means are compared, and based on the deviation, the moisture content of the printing paper is adjusted to the set moisture content. Means for humidifying or drying the printing paper is provided. Therefore, the moisture content of the printing paper is automatically adjusted on the printing press so that the paper has sufficient strength before being folded by the folding machine of the printing machine, and also has a good moisture content in the end. can do. Therefore, it is possible to reliably prevent not only spine cracking but also a decrease in core strength and overdry printing failures including waving. Furthermore, when an infrared absorption moisture meter is used as the moisture content detection means, the moisture content of the printing paper can be accurately detected.

【Example】

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a process diagram showing a state in which an embodiment of the present invention is attached to a rotary offset printing press. The printing paper 10 on the web, which has been conveyed from the left side of the figure, has ink transferred to the front and/or back side in the printing unit 12, and then passes through a hot air dryer 14, for example, so that the solvent component of the ink is evaporated. After being dried, the web is cooled by the cooling roller 18 of the cooling section 16. The web that has passed through the cooling section 16 is cut into predetermined dimensions and folded by a folding machine 20. In the rotary offset printing press configured as described above, a moisture detector 23 of an infrared absorption moisture meter 22 for implementing the present invention is provided between the cooling section 16 and the folding machine 20. The infrared absorption moisture meter 22 detects moisture in the printing paper 10 by absorbing infrared rays by the moisture in the paper. Since deterioration in quality strength such as back cracking and deterioration in core strength mainly occurs in the folding machine 20, it is effective to provide the moisture detector 23 immediately before the folding machine 20. Note that the position of the moisture detector 23 is not limited to this, and it is also possible to provide it on the entrance side of the cooling section 16, for example. In the latter case, since the temperature of the printing paper 10 is high, it is also necessary to consider the difference in moisture content due to the difference in temperature. As shown in detail in FIG. 2, the infrared moisture absorption needle 22 includes a light projector 24 for projecting near-infrared light including an absorption band due to water, and a light projector 24 for receiving light reflected by the surface of the printing paper 10. It includes a reflection type light receiver 26. The light projector 24 has a measurement wave length of, for example, 1.94 μm).
A lamp 24A as a light source that generates near-infrared light including the measurement wavelength and the comparison wavelength (for example, 1.80 μm), a lens 24B that converts the light from the lamp 24A into parallel light, and a lamp 24B that emits only the near-infrared light of the measurement wavelength and the comparison wavelength. A rotary plate 24D to which two interference filters 24E and F are attached for alternate transmission, a synchronous motor 24G for rotating the rotary plate 24D, and a light emitting diode that generates light for synchronizing the rotation. 24H, and a light receiver 24J that receives light transmitted through a through hole 24I formed at a specific position of the rotary plate 24D and generates a synchronizing signal. In the figure, 24 is a mirror for changing the direction of the light collimated by the lens 24B. The reflective light receiver 26 includes, for example, an integrating sphere 26A for collecting opposite light, and a light receiver 26B for converting the light collected by the integrating sphere 26A into an electrical signal. In order to prevent errors in infrared absorption due to ink, it is desirable that moisture detection by the moisture detector 23 be performed on an unprinted blank portion 10A of the printing paper 10, as shown in FIG. Therefore, in this embodiment, the moisture detector 23 is mounted on a rail 28 provided in a direction perpendicular to the traveling direction of the printing paper 10, so that it can be moved left and right. Generally, blank areas on printing paper are located at the same position for the same printed matter, so it is sufficient to manually adjust the widthwise position of the moisture detector 23 along the rail 28 each time according to the printed matter. Note that the position of the moisture detector 23 can be driven and adjusted, and a separately provided sensor detects the blank portion 10A on the printing paper, for example, because the reflectance of the surface of the printing paper 10 is maximum. It is also possible to configure the position of the moisture detector 23 to be automatically controlled in the blank area. The signal obtained by the moisture detector 23 is sent to a moisture content converter 31 (see FIG. 2) of a moisture content calculation device 30. This moisture content converter 31 includes an amplifier 31A that amplifies the light reception signal obtained by the light receiver 26B of the reflective light receiver 26, and a synchronization signal output from the light receiver 24J of the light projector 24 to convert the output of the amplifier 31A into A synchronous detection circuit 31B that performs synchronous detection, a memory 31C131D that stores measurement signals and reference signals alternately output from the synchronous detection circuit 31B, and a received light amount signal at two wavelengths is divided and output as a detector output. Divide circuit 3 to output
1E. In addition to the moisture content converter 31, the moisture content calculation device 30 shown in FIG. 1 also includes, for example, a digital display 32 for displaying the moisture content. The detected moisture content output from the moisture content calculator 31 is input to the humidifier control device 33. This warmer control device 33 includes:
Digital switch 3 for setting the target moisture content of printing paper
4 is provided, the detected moisture content is compared with the set moisture content set by the digital switch 34, and if the detected moisture content is higher than the set moisture content, for example, the spray humidifier 36 is controlled. For example, water is sprayed onto the web of printing paper 10 from a spray nozzle 38 provided immediately after the hot air dryer 14 to humidify the web. Note that an appropriate number of spray nozzles 38 can be disposed in the width direction on one or both sides of the web. In addition,
The arrangement position of the spray nozzle 38 is not limited to between the hot air dryer 14 and the cooling section 16, and it may be provided between the cooling section 16 and the folding machine 20 as long as it is in front of the moisture detector 23. FIG. 4 is a block diagram showing in detail the configuration of the moisture content calculation device 30 including the moisture content converter 31 and the display 32, the humidifier control device 33 including the digital switch 34, and the spray humidifier 36. It is a diagram. Hereinafter, the operation of this embodiment will be explained in more detail with reference to FIG. The moisture content calculation device 30 uses a moisture content calculation unit 42 to calculate a moisture content detection signal inputted from the moisture detector 23 via the moisture content converter 31 into a moisture value. Generally, the relationship between the moisture detector output and the moisture content varies depending on the printing paper, and has a unique relationship for each printing paper, as shown in the calibration curve shown in FIG. 5, for example. Therefore, the calibration curve data is created and stored in a separate location, and when the moisture meter is used, the calibration data is sent to the moisture content calculation unit 42 for each printing paper via the communication line 44 and the communication interface 46. The moisture value can be calculated from the moisture detector 22 output by inputting the moisture value. The moisture value calculated by the moisture content calculating section 42 is digitally displayed on the digital display 32. The humidifier control device 33 includes the setting digital switch 34
, a comparator 48 that compares the target moisture value set with the setting digital switch 34 and the measured moisture value and outputs a signal according to the deviation, and a comparator 48 that outputs a signal according to the deviation, and a It is configured to include a valve control circuit 50 that controls an electromagnetic valve. This valve control circuit 50 controls opening and closing of the continuously variable water valve 52 of the spray humidifier 36 in accordance with the amount of deviation when a deviation signal indicating that the detected moisture value is lower than the set moisture value is output from the comparator 48. do. This continuously variable valve 52
is supplied with water through a pipe 54, and this water is led to the spray nozzle 38. Further, the valve control circuit 50 connects the spray nozzle 3 via a pipe 56.
Since the high-pressure air opening/closing valve 58 and the water opening/closing valve 60 supplied to the spray nozzle 8 are also opened, water is sprayed from the spray nozzle 38 according to the moisture deviation. Conversely, if the detected moisture value is higher than the set moisture value, the continuously variable water valve 52, the water on-off valve 60, and the air on-off valve 58 are all closed, so the spray nozzle 38
No water is sprayed from. In addition, when the printing machine is stopped, the detected moisture value becomes unstable due to slack in the paper, so to prevent erroneous humidification, the signal line 62
A start/stop signal is input from the printing machine via the printer, and it is possible to control the printer so that it does not spray while it is stopped. In this embodiment, since an infrared absorption moisture meter of the reflected light measurement type is used as the moisture meter, the moisture content of the printing paper 10 can be detected easily and accurately. The type of moisture meter is not limited to this, and a transmitted light measurement type, for example, a microwave absorption type, high frequency type (dielectric type), radiation type (neutron absorption type), etc., or a pond type moisture meter may be used. It is also possible. Further, in this embodiment, since a spray humidifier is used as the humidifying means, the configuration is simple. Note that the configuration of the humidifying means is not limited to this, and it is also possible to use other types of humidifiers such as an ultrasonic humidifier or an electrostatic humidifier, or even use a dryer as necessary. be.

[Brief explanation of the drawing]

FIG. 1 is a process diagram showing the overall configuration of an offset rotary printing press in which an embodiment of the present invention is installed, and FIG. 2 is a block diagram showing the configuration of an infrared absorption moisture meter used in the embodiment. 3 is a perspective view showing the mounting state of the moisture detector in the embodiment, and FIG. 4 is a diagram showing the configuration of the moisture content calculation device, humidifier control device, and spray humidifier in the embodiment. The block diagram shown in FIG. 5 is a diagram showing an example of a calibration curve used in the water content calculation device. 10...Printing paper, 12...Printing unit, 14...Hot air dryer, 2o...Folding machine,
22... Infrared absorption moisture meter, 23... Moisture detector, 3o... Moisture content calculation device, 33... Humidifier control device, 34... Setting digital switch, 36... Spray humidification Container, 38...Spray nozzle.

Claims (2)

[Claims] (1) On the printing press, a means for detecting the moisture content of the printing paper, a means for setting the target moisture content of the printing paper, and a means for comparing the detected moisture content and the set moisture content, and based on the deviation, determine the moisture content of the printing paper. 1. A printing paper moisture regulating device on a printing press, comprising: means for humidifying or drying the printing paper on the printing press so that the moisture content of the printing paper becomes a set moisture content. (2) The printing paper moisture content regulating device on a printing press according to claim 1, wherein an infrared absorption moisture meter is used as the moisture content detecting means.