JP5703658B2 - Supply air fan speed control system, supply air fan speed control method, gravure printing machine - Google Patents

Description

  The present invention relates to an air supply fan rotation speed control system, an air supply fan rotation speed control method, and a gravure printing machine in a gravure printing machine drying apparatus.

  Conventionally, gravure printing using a gravure printing machine is known as one of printing methods. FIG. 4 is a diagram showing a schematic configuration of a gravure printing machine, and FIG. 5 is a diagram showing a process of gravure printing.

  As shown in FIG. 4, the gravure printing machine 10 includes a paper feed unit (not shown), a paper discharge unit (not shown), and a plurality of printing units 3 (3a, 3b, 3c). Each printing unit 3 performs printing for each color (for example, cyan, magenta, yellow, sumi, special color, etc.). The printing material 13 fed from the paper feeding unit is conveyed by a plurality of conveying rollers 15 in the order of the printing unit 3a, the printing unit 3b, and the printing unit 3c, and each color is printed and discharged to the paper discharge unit. .

  Each printing unit 3 includes an impression cylinder 5, a plate cylinder 7, an ink pan 9, a finisher roll 72, a doctor blade 73, an air cylinder 75, a drying device 81, and the like. The ink pan 9 contains the ink 11 of the color of each printing unit 3. The air cylinder 75 adjusts the pressure applied to the impression cylinder 5 so that a uniform pressure is applied to the conveyed printing material 13.

  As shown in FIG. 5 (a), in gravure printing, generally, a plate cylinder 7 is provided on an ink pan 9, and the plate cylinder 7 rotates (direction A in the figure) so that the surface of the plate cylinder 7 is formed. Ink 11 adheres. As for the ink 11 adhered to the entire surface of the plate cylinder 7, as shown in FIG. 5B, the excess ink 11 is scraped off by the doctor blade 73, and the ink 11 is applied only to the cells 71 that are the concave portions of the plate cylinder 7. Will be filled.

  Next, as shown in FIG. 5 (c), between the plate cylinder 7 and the impression cylinder 5 provided so as to be close to the plate cylinder 7 and rotating in the opposite direction (B direction in the figure). The ink 11 in the cell 71 is applied to the printing material 13 such as paper, cellophane, OPP (orientated polypropylene), PET (polyethylene terephthalate), nylon, or the like that passes in the transport direction (direction C in the figure). Be transferred. About the printing material 13, the ink 11 on the printing material 13 is dried with the hot air 35 of the drying apparatus 81 provided in the position further advanced in the conveyance direction, and the printing process of 1 color is complete | finished.

  The gravure printing machine 10 requires electric power, steam, compressed air, cooling water, etc. as energy. In particular, in the drying device 81 that dries the ink 11 attached to the printing material 13, hot air 35 is applied to the printing material 13. In order to blow and dry, a large amount of electric power is consumed for generating steam for heating the outside air and operating an air supply fan provided for blowing hot air 35. It is important from the viewpoint of energy saving to reduce the consumption of steam and electric power.

  Conventionally, for this purpose, when the printing is not performed for a long time, the method of stopping the operation of the air supply fan has been adopted, or when the gravure printing machine is in operation, the air volume is adjusted according to the state in the drying device. A method of reducing energy during operation has also been proposed (Patent Document 1).

  In the method of Patent Document 1, a temperature controller and a pressure controller are provided at the dryer inlet, the rotation of the modular roll motor is controlled according to the temperature measured by the temperature controller, and the opening and closing control of the mixing damper that changes the ratio of hot air and cold air is performed. The inverter is controlled according to the pressure measured by the pressure controller to control the rotation speed of the air supply fan, and the process conditions for drying during the operation of the gravure printing machine are checked to reduce energy.

JP-A-6-344536

  By the way, at the time of color matching work before the main printing (printing as a product), by comparing the test printed matter with the color sample, the work of matching the color of the ink 11 with the color equivalent to the color sample, There is a relatively short time during which the gravure printing machine 10 does not perform printing for several minutes to about 10 minutes. Conventionally, for such a short time, the air supply fan continues to operate as it is, and the consumption of steam and power at this time cannot be reduced.

  The reason why the air supply fan is not stopped when printing is stopped for such a relatively short period of time is that when the air supply fan is stopped and then the air supply fan is operated to start printing again, This is because it takes time until the temperature of the gravure is stabilized, and the operation efficiency of the gravure printing machine 10 may be reduced.

  On the other hand, the method of Patent Document 1 is an effective technique during operation of the gravure printing machine, but does not reduce energy that is wasted other than during operation.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an air supply fan rotation speed control system and the like that reduce energy consumed by a drying device depending on an operating state of a gravure printing machine.

According to a first aspect of the present invention for achieving the above object, whether or not an air supply fan of a drying device of a gravure printer is in a predetermined operation state and whether or not printing is being performed by the gravure printer. When the operation state detection means to detect and the operation state detection means detect that the air supply fan is in a predetermined operation state and printing is not being performed, the rotation speed of the air supply fan is determined. The supply air rotation speed control means for reducing and the flow of supplying hot air to the drying device via the supply air fan when the rotation speed of the supply air fan is reduced by the supply air fan speed control means. based on the temperature information measured by the temperature measuring device provided in the road, anda steam amount adjusting means for adjusting the amount of steam supplied to the heat exchanger for heating the outside air supplied to the drying apparatus The amount of steam The means increases the amount of steam supplied to the heat exchanger when the temperature of the temperature information measured by the temperature measuring device decreases, so that the heating temperature of the outside air increases, and the drying device It is an air supply fan rotational speed control system characterized by suppressing the temperature fall of the hot air used by this.

The operating state detection means detects, for example, whether the gravure printing machine is printing by detecting whether the impression cylinder of the gravure printing machine is in a state of being separated from the plate cylinder. . The steam is sent to the heat exchanger by the rotation of the air supply fan.

According to a second aspect of the present invention, the operation of detecting whether or not the air supply fan of the drying device of the gravure printing machine is in a predetermined operation state and whether or not printing is being performed by the gravure printing machine is performed. In the state detection step and the operation state detection step, when it is detected that the air supply fan is in a predetermined operation state and printing is not performed, the air supply fan rotation speed control means performs the air supply When the rotation speed of the supply air fan is reduced in the supply air fan rotation speed control step and the supply air fan rotation speed control step to reduce the rotation speed of the fan, the drying device is connected to the drying device via the supply air fan. A steam amount adjusting step for adjusting the amount of steam supplied to the heat exchanger for heating the outside air supplied to the drying device based on temperature information measured by a temperature measuring device provided in a flow path for supplying hot air and, the equipped, In the steam amount adjusting step, when the temperature of the temperature information measured by the temperature measuring device is decreased, the amount of steam supplied to the heat exchanger is increased so that the heating temperature of the outside air is increased. A method for controlling the rotational speed of an air supply fan that suppresses a temperature drop of hot air used in the drying device .

In the operation state detection step, for example, it is detected whether or not printing is being performed by the gravure printing machine by detecting whether or not the impression cylinder of the gravure printing machine is in a state separated from the plate cylinder. . The steam is sent to the heat exchanger by the rotation of the air supply fan.

  A third invention is a gravure printing machine provided with the supply fan rotation speed control system of the first invention.

According to the present invention, a state in which printing on the printing material is not performed is detected from the attachment / detachment state of the impression cylinder, and the supply fan is set to a predetermined (normally) state in conjunction with the detection of the operation state of the supply fan of the drying device (Ii) When printing is not being performed, it is determined that printing is in a small stop state. In this case, it is possible to reduce the rotation speed of the air supply fan and reduce energy consumption.
At this time, a decrease in the temperature of the air passage due to a reduction in the number of rotations of the air supply fan is detected, and accordingly, the amount of steam for heating the outside air supplied to the drying device is increased, so that the hot air supplied to the drying device is increased. It is possible to prevent a decrease in temperature and to smoothly raise the blowing temperature of the drying device when the gravure printing machine is restarted after a small stop.

  From the above, it is possible to provide an air supply fan rotation speed control system or the like that reduces the energy consumed by the drying device depending on the operating state of the gravure printing machine.

1 is a schematic configuration diagram showing a configuration of an air supply fan rotation speed control system 1 according to an embodiment of the present invention. The flowchart which shows the flow of a process of the air supply fan rotation speed control system 1 The schematic block diagram which shows the structure of the air supply fan rotation speed control system 1a which concerns on another Example of this invention. Schematic configuration diagram showing the configuration of the gravure printing machine 10 Diagram showing the outline process of gravure printing

Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings.
FIG. 1 is a schematic configuration diagram showing a configuration of an air supply fan rotation speed control system 1 according to an embodiment of the present invention. An air supply fan rotation speed control system 1 according to the present invention is provided in a gravure printing machine 10 whose examples are shown in FIGS.

  As described with reference to FIGS. 4 and 5, the gravure printing machine 10 includes a plurality of printing units 3 (3 a, 3 b, 3 c,...), And each printing unit 3 includes a drying device 81. . FIG. 1 shows only one of the printing units 3 in the gravure printing machine 10. Further, the printing unit 3 having the same configuration as that described in FIGS. 4 and 5 is denoted by the same reference numeral, and a part of the description is omitted.

  As shown in FIG. 1, the drying device 81 includes a drying hood 27 for blowing hot air 35 onto the printing material 13, and the printing material 13 is conveyed through the drying hood 27 by a plurality of conveying rollers 15. A drying process of the printed ink 11 is performed.

  The drying device 81 is provided with a flow path 22 such as a pipe for taking in and heating the outside air 33 by the air supply fan 21 and supplying the hot air 35 to the drying device 81. A heat exchanger 23, an air supply fan 21, a resistance temperature detector 29, and the like are attached to the flow path 22. Further, the heat exchanger 23 is provided with a flow path 26 for supplying the steam 31 to the heat exchanger 23, and the steam 31 supplied via the flow path 26 causes the outside air 33 in the heat exchanger 23. Is heated. A steam amount adjusting valve 25 is provided in the flow path 26, and the amount of steam supplied can be controlled by adjusting the opening degree.

  The steam 31 travels in the direction toward the heat exchanger 23 (direction a in the figure) through the flow path 26 by the air supply fan 21, and the steam inflow amount to the heat exchanger 23 is adjusted by the steam amount adjusting valve 25. The steam 31 whose flow rate has been adjusted enters the heat exchanger 23. On the other hand, the outside air 33 travels in the flow path 22 in the direction toward the heat exchanger 23 (direction b in the figure), enters the heat exchanger 23, and is heated by the steam 31. The heated air (hot air 35) travels through the flow path 22 from the heat exchanger 23 to the supply fan 21, and the amount of hot air 35 according to the rotation speed of the supply fan 21 travels through the flow path 22 to the drying hood 27. It proceeds to the direction (c direction in the figure) and is supplied to the drying device 81 and sprayed onto the printing material 13. The hot air 35 blown onto the printing material 13 travels in the direction toward the outside (direction d in the figure) through the flow path 36 provided in the drying hood 27 and is discharged as exhaust 37.

  The air supply fan rotation speed control system 1 of the present embodiment provided in the above-described gravure printing machine 10 controls the rotation speed of the air supply fan 21, and the air supply fan rotation speed control device 2, A position sensor 5a provided on the pressure drum 5, a resistance temperature detector 29, a steam amount adjusting valve 25, and the like are included.

  The supply fan rotation speed control device 2 is composed of, for example, a sequencer and the like, is composed of a calculation unit, a memory, an input / output interface, and the like, and performs control under predetermined conditions according to a flowchart described later. The memory stores a program for performing sequencer processing and data used for the processing. The supply fan rotation speed control device 2 may also serve as the control device for the gravure printing machine 10 or may be provided separately from the control device for the gravure printing machine 10.

  The position sensor 5 a is provided on the impression cylinder 5 and inputs impression cylinder information 41, which is information indicating the attachment / detachment state of the impression cylinder 5, to the air supply fan rotation speed control device 2. The wearing state is a state in which the impression cylinder 5 is close to the plate cylinder 7, and the above-described printing is being performed. On the other hand, the detached state indicates that the impression cylinder 5 is located away from the plate cylinder 7 and printing is not performed. The position sensor 5 a detects the position state of these impression cylinders 5 and inputs it as the impression cylinder information 41 to the supply fan rotation speed control device 2. However, the information indicating the attachment / detachment state of the impression cylinder is not limited to the impression cylinder information 41 described above. For example, when a signal instructing attachment / detachment of the impression cylinder 5 is sent from the air supply fan rotation speed control device 2, Information of this signal being transmitted may be used as it is.

  The resistance temperature detector 29 is a temperature measuring device that is provided between the heat exchanger 23 and the drying hood 27 in the flow path 22 and measures the temperature of the hot air 35 supplied to the drying hood 27. The temperature measurement value by the resistance temperature detector 29 is input to the supply fan rotation speed control device 2 as temperature information 47.

  Further, for the supply fan rotation speed control in the supply fan rotation speed control device 2, supply fan operation information (not shown) indicating the operation / stop state of the supply fan 21 is used. For this, the information of the rotation speed command 43 instructing the rotation, the rotation speed, and the like transmitted from the supply fan rotation speed control device 2 to the supply air fan 21 can be used. Alternatively, as with the impression cylinder information 41, a sensor (such as an air flow sensor) for detecting the operation / stop state is provided in the air supply fan 21, and the information from the sensor is used as the air supply fan operation information to control the air supply fan speed. You may input into the apparatus 2. FIG.

  The supply fan rotation speed control device 2 supplies a rotation speed command 43 for controlling the rotation speed of the supply fan 21 by sequence control based on the impression cylinder information 41, temperature information 47, supply fan operation information, and the like. A steam amount command 49 for controlling the amount of steam flowing into the heat exchanger 23 according to the opening degree of the steam amount adjusting valve 25 is output to the fan 21 to the steam amount adjusting valve 25.

  For example, when the gravure printing machine 10 is operated, a rotation speed command 43 of, for example, 50 Hz, which is a normal rotation speed, is output to the air supply fan 21, and the motor is controlled via an inverter. In addition, the rotation of the air supply fan 21 is controlled. Further, a steam amount command 49 is output to the steam amount adjusting valve 25, and the opening of, for example, an electromagnetic valve of the steam amount adjusting valve 25 is controlled to a normal state.

  Next, the flow of the supply fan rotation speed control by the supply fan rotation speed control system 1 will be described with reference to FIG. FIG. 2 is a flowchart showing a process flow of the supply fan rotation speed control system 1.

  In the air supply fan speed control by the air supply fan speed control system 1, first, the air supply fan speed control device 2 determines the operating state of the air supply fan 21 (step S101). As described above, the operating state of the air supply fan 21 can be determined, for example, based on the value of the rotational speed command 43 to the air supply fan 21 transmitted from the air supply fan rotational speed control device 2. If the air supply fan 21 is “0”, it is possible to detect that the air supply fan 21 is stopped, and if the air supply fan 21 is in a predetermined operation state (normal operation state) if it is a predetermined value (for example, 50 Hz). .

  When the air supply fan 21 is stopped in step S101, the gravure printing machine 10 is not operating and is in a stopped state for a long period of time, and the air supply fan rotation speed control device 2 rotates (without special control). (Frequency) A state of 0 Hz (stop of the air supply fan 21) is maintained (step S102).

  On the other hand, when the air supply fan 21 is in operation in step S101, next, the attachment / detachment state of the impression cylinder 5 is determined (step S103). Thus, it is detected whether printing is being performed. The attachment / detachment state of the impression cylinder 5 is determined by the impression cylinder information 41 from the position sensor 5a.

  If the impression cylinder information 41 indicates the wearing state of the impression cylinder 5, it is determined that the normal printing is being performed, and the air supply fan rotation speed control device 2 sends the rotation speed command 43 to the normal operation of the gravure printing machine 10. Continues the control set to the supply fan speed. For example, the rotation speed is set to 50 Hz (step S105).

  When the impression cylinder information 41 indicates that the impression cylinder 5 has been removed, it indicates that the impression cylinder 5 is separated from the plate cylinder 7 even though the air supply fan 21 is in operation, and the gravure printing machine 10 is in a small stop state. It is judged that. In this case, the air supply fan rotation speed control device 2 sets the rotation speed command 43 sent to the air supply fan 21 to, for example, 25 Hz which is 1/2 of the normal rotation speed, and sets the rotation speed of the supply air fan 21 to the normal operation. Lower than the state (step S104).

  In step S <b> 104, temperature information 47 measured by the resistance temperature detector 29 is input to the supply fan rotation speed control device 2. When the temperature of the temperature information 47 measured by the resistance temperature detector 29 decreases, the supply fan rotation speed control device 2 controls the opening of the steam amount adjustment valve 25 according to the temperature information 47 and performs heat exchange. The steam amount command 49 is output so as to increase the amount of the steam 31 flowing into the oven 23, and the heating temperature of the outside air 33 in the heat exchanger 23 is increased by the increase in the amount of steam, so that the hot air used in the drying device 81 is increased. The temperature drop of 35 is suppressed.

This is because if the rotational speed of the air supply fan 21 is reduced in step S104, the supply amount of the steam 31 is also reduced, whereby the temperature of the hot air 35 is lowered, and when the gravure printing machine 10 is restarted as it is, the temperature of the hot air 35 is increased. This is because it takes time to raise the temperature to a predetermined temperature again to achieve a stable state, thereby reducing the operation efficiency of the gravure printing machine 10. The supply air fan speed control device 2 suppresses a decrease in the temperature of the hot air 35 by the above processing, thereby increasing the time until the hot air 35 is raised to a predetermined temperature and stabilized after recovery from the small stop state. The operation can be resumed without shortening the operating efficiency of the gravure printing machine 10.
In addition, since the rotation speed of the air supply fan 21 is lower than normal, even when the above processing is performed, the amount of supplied steam is reduced from the normal time.

  After the processes of step S102, step S104, and step S105 described above, the process returns to step S101, and the processes of step S101 to step S105 are repeated. In this embodiment, the rotation speed of the air supply fan 21 during normal operation is reduced to 50 Hz, and the rotation speed during a small stop of printing is reduced to 25 Hz. However, the present invention is not limited to this. However, there is a proportional relationship between approximately the third power of the rotational speed of the air supply fan 21 and the consumed energy, and if the rotational speed is lowered to a certain extent, the energy saving effect is small even if the rotational speed is lowered further, and printing is resumed. Considering shortening the rise time when the rotation speed of the air supply fan 21 is sometimes increased, it is preferable to reduce it to about ½ as described above.

  Through the above processing, the operation state of the gravure printing machine 10 is detected by the air supply fan rotation speed control device 2, and when the air supply fan 21 is operating normally even though printing is not being performed, it is automatically performed. In addition, energy saving is realized by reducing the number of rotations of the air supply fan 21.

  That is, the air supply fan rotation speed control system 1 determines whether or not the air supply fan 21 that supplies hot air to the drying device 81 is in a predetermined operation state and whether or not the gravure printing machine 10 is printing. When the position sensor 5a, the air supply fan rotation speed control device 2, etc. are provided as the operating state detection means to detect, and it is detected that the air supply fan 21 is in a predetermined rotation speed state and printing is not being performed. In addition, the air supply fan rotational speed control device 2 or the like is provided as an air supply fan rotational speed control means for reducing the rotational speed of the air supply fan 21. Based on the temperature information 47 measured by the body 29, the supply fan rotation speed control device 2, the steam amount adjusting valve 25, etc. are provided as steam amount adjusting means for adjusting the amount of steam supplied to the heat exchanger 23. With this configuration By gas fan speed control system 1 it is made possible above processing.

  In the above description, whether or not the gravure printing machine 10 is operated and printing is determined based on the attachment / detachment state of the impression cylinder 5, but it is determined whether or not printing is being performed by another method. Also good.

  An example thereof is an air supply fan rotation speed control system 1a shown in FIG. 3, and instead of the position sensor 5a, in the vicinity of the impression cylinder 5, the conveyance direction of the printing material 13 relative to the impression cylinder 5 (e in FIG. 3). The image sensor 28 is provided at a front position in the direction). Other configurations are the same as those of the supply fan rotation speed control device 1 shown in FIG. 1, and therefore, the same numbers are given to the drawings and the description thereof is omitted.

  For example, even in a state where printing is not performed, the printing material 13 may be conveyed in order to extend the slack. In this case, since the printing material 13 is conveyed without printing, whether or not printing is performed is determined by determining whether or not printing is performed on the printing material 13 by the image sensor 28 described above. Can be detected. In this case, for example, the image sensor 28 inputs print information 42 indicating whether or not the printing material 13 has a portion other than the ground color to the air supply fan rotation speed control device 2. In step S103 of FIG. 2, the supply fan rotation speed control device 2 detects whether or not printing is being performed by determining whether or not there is a portion other than the ground color. As a result, it is possible to proceed with the subsequent processing in the same manner as in FIG. 2 and reduce the number of rotations of the paper feed fan 21, thereby realizing energy saving.

With the above air supply fan rotation speed control system, it is possible to automatically reduce the rotation speed of the air supply fan 21 without increasing the work burden on the operator and without increasing the cost. It is possible to reduce energy consumption by reducing the amount of electric power for rotating 21 and the consumption of steam 31 that creates hot air 35.
For example, in a general gravure printing machine, the case where the supply fan rotation speed control system of the present invention is applied was examined. As a result, the electric energy was reduced to about 1/8 without reducing the printing operation efficiency. The knowledge that can be reduced to about 2/3 was obtained.

  The preferred embodiments of the air supply fan speed control system and the like according to the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea disclosed in the present application, and these naturally belong to the technical scope of the present invention. Understood.

DESCRIPTION OF SYMBOLS 1, 1a ... Supply air fan speed control system 2 ... Supply air fan speed control device 5 ... Impression cylinder 7 ... Plate cylinder 10 ... Gravure printing machine 11 ... Ink 13 ... …… Print material 21 ……… Air supply fan 23 ………… Heat exchanger 25 ……… Steam amount adjusting valve 27 ……… Dry hood 29 ………… Temperature measuring resistor 31 ……… Steam 33 ……… Outside air 35 ..... Hot air 37 ..... Exhaust 41 .... Pressure cylinder information 42 .... Printing information 43 ....... Revolution number command 47 ....... Temperature information 81 ....... Drying device

Claims (7)

An operation state detecting means for detecting whether or not the air supply fan of the drying device of the gravure printing machine is in a predetermined operation state, and whether or not printing is being performed in the gravure printing machine;
Air supply fan rotation speed control for reducing the rotation speed of the air supply fan when the operation state detecting means detects that the air supply fan is in a predetermined operation state and printing is not performed. Means,
When the rotational speed of the air supply fan is reduced by the air supply fan speed control means, the temperature is measured by a temperature measuring device provided in a flow path for supplying hot air to the drying device via the air supply fan. Steam amount adjusting means for adjusting the amount of steam supplied to the heat exchanger for heating the outside air supplied to the drying device based on temperature information;
Equipped with,
The steam amount adjusting means increases the amount of steam supplied to the heat exchanger and increases the heating temperature of the outside air when the temperature information measured by the temperature measuring device decreases. An air supply fan rotational speed control system that suppresses a temperature drop of hot air used in the drying device .   The operation state detecting means detects whether the gravure printing machine is printing by detecting whether the impression cylinder of the gravure printing machine is in a state of being separated from the plate cylinder. The supply air fan rotational speed control system according to claim 1, wherein 3. The supply air fan speed control system according to claim 1 , wherein the steam is sent to the heat exchanger by rotation of the supply air fan. An operation state detection step of detecting whether or not the air supply fan of the drying device of the gravure printing machine is in a predetermined operation state, and whether or not printing is being performed by the gravure printing machine, and
In the operation state detecting step, when it is detected that the air supply fan is in a predetermined operation state and printing is not performed, the air supply fan rotation speed control means sets the rotation speed of the air supply fan. An air supply fan speed control step to reduce,
When the rotation speed of the supply air fan is reduced in the supply air fan speed control step, the temperature is measured by a temperature measuring device provided in a flow path for supplying hot air to the drying device via the supply air fan. A steam amount adjusting step for adjusting the amount of steam supplied to a heat exchanger for heating outside air supplied to the drying device based on temperature information;
Comprising
In the steam amount adjusting step, when the temperature of the temperature information measured by the temperature measuring device decreases, the amount of steam supplied to the heat exchanger is increased so that the heating temperature of the outside air is increased. An air supply fan rotation speed control method for suppressing temperature drop of hot air used in the drying device .   In the operation state detection step, detecting whether the gravure printing machine is printing is performed by detecting whether the impression cylinder of the gravure printing machine is in a state separated from the plate cylinder. The method of controlling an air supply fan speed according to claim 4. 6. The supply air fan speed control method according to claim 4 , wherein the steam is sent to the heat exchanger by rotation of the supply air fan.   A gravure printing machine provided with the supply fan rotation speed control system according to any one of claims 1 to 3.

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