JPH04212859A - Sheet surface temperature control device for rotary printer drier - Google Patents

Abstract

PURPOSE:To provide a sheet surface temperature control device for a rotary printer drier to dry ink on a printed sheet by a hot blast heating system by providing a direct combustion type deodorizing device, and a heat recovering device to re-heat hot blast, circulating in the drier, by means of exhaust gas. CONSTITUTION:In a printer drier provided with a bypass line installed to a hot blast circulating line and bypassing a heat recovery device, a sheet surface temperature control device comprises a control device to control a printing sheet surface temperature to a given value through control of the opening of a damper located in the bypass line and a combustion amount of a preheat burner and a control output setter to reset the output value of the control device to a given value responding to a time change amount of a printing speed once.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper surface temperature control device for a rotary printing press dryer.

0002

[Prior art] Conventional rotary printing press drying device (dryer)
For example, the device shown in FIG.
It has been proposed as No. 912. Referring to FIG. 7, the operation of the drying device of the rotary printing press will be specifically explained. At the start of operation before normal operation, the exhaust gas blower 7 is activated,
Outside air (combustion air) is sucked into the drying device main body 1, and the outside air sucked into the drying device main body 1 is passed through the exhaust gas blower 7 → inside the heat transfer tube of the preheater 11 → the direct combustion reactor 12 → the preheater 11. The outside of the heat transfer tube is led into the heat transfer tube of the heat recovery device 9. In addition, the first zone blower 5 and the second zone blower 6 are operated,
After the outside air sucked into the drying device main body 1 is circulated within the drying device main body 1, the preheating burner 4 is ignited and burned to heat the air circulating inside the drying device main body 1.

[0003] Also, the air in the drying device main body 1 is guided as combustion air from the exhaust gas blower 7 to the heat transfer tube of the preheater 1 to the direct combustion reactor 12, and the fuel from the deodorizing burner 10 is ignited and combusted. At that time, the generated exhaust gas is guided from outside the heat transfer tube of the preheater 11 to inside the heat transfer tube of the heat recovery device 9, and after preheating the air circulating inside the drying device main body 1 as described above, the drying device Discharge outside the main body 1. As a result, the temperature of the circulating air within the drying device main body 1 quickly rises to a predetermined temperature at the start of operation before normal operation.

[0004] When this state is reached, the preheating burner 4 is stopped and normal operation begins. At this time, the printing paper 2 printed by the rotary printing machine is guided into the drying device main body 1, and hot air is blown from the hot air blowing nozzle 3 into the printing paper path, hitting the printing paper 2, and ink on the printing paper 2. While evaporating the solvent contained in the evaporated solvent, the hot air (exhaust gas at about 140 to 170°C) containing the evaporated solvent is transferred to the heat recovery device 9 on the suction side of the first zone blower 5 and the second zone blower 6. The exhaust gas passing through the inside of the heat exchanger tube of the heat recovery device 9, that is, the exhaust gas from the direct combustion reactor 12 of the direct combustion deodorizing device 8 (exhaust gas at about 400 to 500°C), returns to the outside of the heat exchanger tube. Reheat to ~250℃,
The hot air is sent to the hot air blowing nozzle 3. Further, a part of the hot air in the drying device main body 1 is sucked by the exhaust gas blower 7 and guided into the preheater 11 of the direct combustion type deodorizing device 8, where it is preheated by the exhaust gas from the direct combustion type reactor 12. Direct heating reactor 12
That is, the hot air is guided to a direct combustion reactor 12 heated to about 700 to 1000°C by a deodorizing burner 10, the evaporated solvent in the hot air is burned, the hot air is deodorized, and the exhaust gas generated at this time is heat recovered. After being led into the heat exchanger tube of the device 9 and performing the above heat exchange, it is discharged to the outside of the drying device main body 1.

Drying control during normal operation is managed by the temperature of the printed paper surface. That is, so that the paper surface temperature obtained by the paper surface temperature detector 13 provided at the outlet of the drying device main body 1 becomes a predetermined value.
The paper surface temperature control device 14 operates the combustion amount of the deodorizing burner 10.

[0006]

SUMMARY OF THE INVENTION The above-mentioned prior art has the following problems. At startup, the temperature of the hot air can be raised in about 1 minute using the preheating burner 4. However, if the printing speed drops during normal operation due to printing machine trouble or adjustment, there is no effective cooling mechanism for hot air. In other words, the temperature inside the deodorizer furnace must have a lower limit temperature to obtain deodorizing performance.
Furthermore, since the heat capacity of the heat exchanger and the like is large, the responsiveness of the paper surface temperature is very poor. Therefore, the paper surface temperature exceeds a predetermined value for a long time, resulting in a large amount of paper waste.

[0007]

[Means for solving the problem] As shown in Figure 1,
A bypass line that bypasses the heat recovery device 9 is provided in the hot air circulation line of one zone, and a damper that adjusts the amount of bypass is provided in the bypass line. (b) The paper surface temperature control device 14 operates two things: the opening degree of the bypass damper and the combustion amount of the preheating burner. This is possible using a converter, which will be described later.

[0008] Furthermore, a control output setting device is provided which detects the printing speed at regular intervals and resets the output value of the paper surface temperature control device 14 to a predetermined value according to the amount of time change in the speed.

[0009]

[Function] If the printing speed decreases while the printing press is running, the paper surface temperature will rise. Therefore, the paper surface temperature control device 14 operates the opening degree of the bypass damper 21 in the opening direction. Since the heat recovery device 9, which is the heat supply source of the hot air, is bypassed, the temperature of the hot air blown from the nozzle in one zone decreases, and at the same time, the paper surface temperature returns to the original temperature. These are performed using feedback control, but in order to further improve responsiveness, we will introduce the concept of feedforward control. That is, the aforementioned control output setting device resets the output value of the paper surface temperature control device to a predetermined value at the same time as the printing speed changes, and suddenly changes the operating end. Set the reset value to be constant (for example, when the speed is "decreased", the bypass opening = 1)
00%), if the amount of change in printing speed is small, it will cause a disturbance, so the reset value is changed depending on the printing speed. Note that when the printing speed returns or increases, the combustion amount of the preheating burner is rapidly increased. In other words, the control is similar to that at startup.

0010

[Example] In Figs. 1 to 6, 1 is a dryer main body;
2 is a printing paper, 3 is a hot air blowing nozzle, 4 is a preheating burner, 5 is a blower for the first zone, 6 is a blower for the second zone,
7 is an exhaust gas blower, 8 is a direct combustion deodorizing device, 9 is a heat recovery device, 10 is a deodorizing burner, 11 is a preheater, 12 is a direct combustion reactor, 13 is a paper surface temperature detector, 14 is a paper surface temperature control 20 is a bypass line, 21 is a damper, 22 is a motor (or cylinder), 24 is a deodorizing device furnace temperature control device, 25 is a furnace temperature detector, 26 is a control output setting device,
27 is a printing speed detector, and 28 and 29 are converters.

A bypass line 20 is provided in the one-zone hot air circulation line, and a damper 21 is installed in the middle of the bypass line 20.
will be established. The paper surface temperature control device 14 is connected to the motor (or cylinder) 22 attached to the damper 21 via a converter 28 and to the preheating burner 4 via a converter 29. The calculation contents of the converters 28 and 29 are shown in FIGS. 2 and 3. In other words, the output CV of the paper surface temperature control device 14 is CV > CV *
When , the preheating burner valve opening opens and closes while the bypass damper opening remains 0%, and when CV > CV *, the bypass damper opens and closes while the preheating burner valve opening remains 0% (that is, extinguishing). degree opens and closes. This allows one control device to operate two operating ends.

Furthermore, since the deodorizing performance is determined by the temperature inside the furnace of the deodorizing device 8, the deodorizing device furnace temperature control device 24 is set with, for example, a lower limit temperature at which a desired deodorizing performance can be obtained. The deodorizing device furnace temperature control device 24 controls the deodorizing burner 10 so that the detected value of the deodorizing device furnace temperature obtained by the detector 25 is equal to the set value.
Manipulate the amount of combustion. The control output setter 26 provides a reset value for the output value of the paper surface temperature control device 14. The printing speed is detected by the printing speed detector 27 at regular intervals (Δtp), and the amount of change in printing speed over time (ΔVs/Δtp) is detected at regular intervals (Δtp).
), the reset value is output. The paper surface temperature control device 14 restarts the PID calculation using the reset value as the initial value. FIG. 4 shows an example of the calculation contents of the preset multiple setter. That is, |ΔVs /Δtp |<ε
(ε is constant), no output occurs. In other words, the paper surface temperature control device 14 performs normal PID calculation. ΔVs/Δt
When p > ε, a reset value equal to or higher than CV* is given. Therefore, the converter 29 resets the valve opening of the preheating burner to a value of 0% or more. Also, ΔVs /Δtp <-
When ε, a reset value equal to or less than CV* is given. Therefore, the converter 28 resets the bypass damper opening to 0% or more.

[0013] For example, when the printing speed suddenly decreases, the bypass damper opening degree immediately becomes 100%, and there is no delay in operation due to feedback control, and control with good responsiveness is possible. Furthermore, a detailed configuration diagram is shown in FIG. In FIG. 5, reference numeral 30 denotes a printing speed time change rate calculating unit, which performs the following calculation at regular intervals (usually on the order of several seconds) tp.

[0014]

[Math 1]

The control output calculator 26 operates at the calculation period tp.
The following processing is performed according to the printing speed time change rate obtained from the printing speed time change rate calculation unit 30 for each time (the calculation contents are shown in FIG. 4).
), the calculation result C for the paper surface temperature control device 14
VR (lit value of paper surface temperature control device output) and f (flag) are output.

[0016]

[Math 2]

The paper surface temperature control device 14 converts the paper surface temperature detection value from the paper surface temperature detector 13 into the paper surface temperature target value from the setting device 31 and the above-mentioned C obtained from the control output calculator 26.
From VR and f, the control output C is obtained by the processing shown in FIG.
Outputs V. In other words, in FIG. 6, the paper surface temperature control device 14 operates when f=0 (that is, when the printing speed time change rate is ±
(within ε), normal PID calculation (details omitted) is performed. f
When =1, the output of the paper surface temperature control device is forcibly reset to the determined control output value C VR in accordance with the printing speed time change rate instead of the PID calculation output. and f=1→0
When the speed returns to normal (the speed becomes steady), the PID calculation is restarted using the reset value as the initial value.

Furthermore, the converters 28 and 29 determine the bypass damper opening command value and the preheating burner valve opening command value, respectively, without the processing lines shown in FIGS. Manipulate the valve opening of the preheating burner. Note that the control output calculator 26 and paper surface temperature controller 14 have a switch to determine whether or not to perform calculations, and when the switch is set to φFF, f l o g =0 in 26, and {CV =
CV*, CV0=CV*} (see FIGS. 2 and 3). Further, the switch is always in the "OFF" state when the power is "ON".

[0019]

Effects of the Invention The paper surface temperature control device for a rotary printing press dryer according to the present invention includes a direct combustion type deodorizing device and a heat recovery device that reheats the hot air circulating inside the dryer using the exhaust gas from the direct combustion type deodorizing device, and prints using a hot air heating method. In a rotary printing press dryer that dries ink on paper, there is a bypass line installed in the hot air circulation line that bypasses the heat recovery device, and printing is performed by manipulating the opening degree of the damper installed in the bypass line or the combustion amount of the preheating burner. a control device that controls the surface temperature to a predetermined value;
a control output setting device that detects the printing speed and, when the amount of time change in the printing speed exceeds a predetermined range, once resets the output value of the control device to a predetermined value according to the amount of time change in the print speed. This has the following effects.

[0020] When the printing speed decreases, the heat recovery device that is the heat source is bypassed, and the amount of bypass is suddenly changed according to the amount of change in the printing speed, so that control without operational delay can be performed, so the hot air temperature can be rapidly lowered. It is possible to control the paper surface temperature with high response. As a result, the effect of improving product yield, that is, reducing paper waste, can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a paper surface temperature control device for a rotary printing press dryer according to an embodiment of the present invention.

FIG. 2 is a relationship diagram between the paper surface temperature control device output and the bypass damper opening command value.

FIG. 3 is a diagram showing the relationship between the paper surface temperature control device output and the preheating burner valve opening command value.

FIG. 4 is a diagram showing an example of calculation contents of a preset manual setting device.

FIG. 5 is a detailed configuration diagram of the temperature and speed control mechanism in FIG. 1;

FIG. 6 is a flow diagram of control according to the present invention.

FIG. 7 is a configuration diagram of a conventional rotary printing press dryer.

[Explanation of symbols]

1 Dryer main body 2 Printing paper 13 Paper temperature detector 14 Paper temperature control device 26
Control output setting device 27 Printing speed detector 28, 29 Converter

Claims (1)

[Claims] Claim 1: A rotary printing press dryer that dries ink on printing paper using a hot air heating method, comprising a direct combustion type deodorizing device and a heat recovery device that reheats hot air circulating in the dryer using exhaust gas from the deodorizing device. a bypass line provided in the circulation line to bypass the heat recovery device; a control device provided in the bypass line that controls the printing paper surface temperature to a predetermined value by manipulating the opening degree of a damper or the combustion amount of a preheating burner; and a control output setting device that detects the printing speed and once resets the output value of the control device to a predetermined value according to the amount of time change in the printing speed when the amount of time change in the printing speed exceeds a predetermined range. A paper surface temperature control device for a rotary printing press dryer, characterized in that: