JP4430768B2 - Ink drying system for stencil printing press - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink drying system for a stencil printing machine.
[0002]
[Prior art]
Conventionally, in a stencil printing machine, ink that requires time for drying is generally used. Therefore, when the printed paper discharged from the stencil press is sequentially stacked on the paper tray and collected, the ink is not sufficiently dried, so the printed surface of the paper below it is printed on the back side of the printed surface of the stacked paper. In some cases, so-called show-through occurs.
[0003]
In order to solve this problem, there has been proposed a method of forcibly drying ink by irradiating printed paper with flash light (for example, JP-A-6-31498).
[0004]
However, since the flash light is irradiated on the entire paper, not only the ink but also the paper itself is heated. In order to dry the ink, it is necessary that the entire paper is first heated to a predetermined temperature or higher, and then the ink portion starts to be dried, which takes time to dry. As a result, there is a high risk that the paper will be wavy.
[0005]
[Problems to be solved by the invention]
Therefore, the technical problem to be solved by the present invention is to provide an ink drying system for a stencil printing machine that can dry ink in a short time while heating the paper itself as much as possible.
[0006]
[Means for solving the problems and actions / effects]
In order to solve the above technical problem, the present invention provides an ink drying system for a stencil printing machine having the following configuration.
[0007]
The ink drying system is arranged between the printer main body and the paper cradle. The printed paper printed by the printer main body is transported to the paper cradle with its printing surface facing up and printed during the transport. This is a type in which the ink on the printed surface of the used paper is forcibly dried. According to the first and second inventions of the present application, the ink drying system of the stencil printing machine includes a conveying unit that supports and conveys the lower surface of the printed paper, and a conveying path that conveys the printed paper. are arranged in the conveying direction of the printed paper alternately positive and negative, each of which extends in a direction transverse to the conveying path, a pair or two or more pairs of electrodes, and a voltage applying means for applying a high frequency voltage to the respective electrodes, the Ru with Tei.
[0008]
In the above configuration, the printed paper printed by the stencil printing machine is sent from the printing machine main body to the ink drying system, and the ink drying system is transported by the transport means with its printing surface facing up. As the conveying means, a system in which printed paper is placed and conveyed on an endless circulation belt, a system in which rotating rollers are arranged and conveyed, or the like can be used. The electrode is disposed along the transport path. The electrodes can be arranged on either one or both of the upper and lower sides of the transport path. A high frequency voltage is applied to each electrode.
[0009]
The printed paper being transported is affected by the change in electric field generated around the electrodes when a high-frequency voltage is applied, and mainly water molecules of the ink on the printed surface rotate to generate frictional heat and dielectric heating. . The paper itself is not heated because it has a low water content and is hardly subjected to dielectric heating. Thereby, the ink on the printing surface on the printed paper can be selectively heated in a short time.
[0010]
Therefore, it is possible to dry the ink in a short time without heating the paper itself as much as possible.
In the first and second inventions of the present application, preferably, a blowing fan for blowing air downward is provided above a conveying path through which the conveying means conveys printed paper.
[0012]
According to the above configuration, the printed paper is blown to the transport unit by the blower fan, and more reliably contacts the transport unit. Therefore, the printed paper can be stably conveyed without directly rubbing the ink on the printed paper.
[0013]
By the way, if high-frequency components leak to the outside during ink drying, there is a risk that peripheral electronic devices may malfunction.
[0014]
Therefore, the first invention of the present application further includes an exterior, an open / close detection unit, a voltage application stop unit, and a warning unit. The said exterior is comprised using a metal material. The exterior substantially seals at least the electrodes and the transport path of the ink drying system. The exterior includes, in part, an opening / closing portion that covers the inside so as to be openable. The opening / closing detection means detects opening / closing of the opening / closing part. The voltage application stopping means stops the application of the high-frequency voltage to each electrode by the voltage applying means when the open / close detecting means detects that the opening / closing portion is open. The warning means issues a warning to the user when the application of the high frequency voltage to each electrode is stopped by the voltage application stopping means.
[0015]
According to the above configuration, the electrode serving as a noise source is substantially sealed and covered with a metal exterior such as aluminum, so that the radiation of electromagnetic waves due to the application of the high frequency voltage can be shielded from leaking outside. This prevents an external control device from receiving electromagnetic waves and creating a noise voltage that becomes a malfunction source within the self-circuit. Further, when the opening / closing part is opened, voltage application is automatically stopped, so that there is no noise source and electromagnetic waves do not leak from the open part of the opening / closing part. Further, at the time of such automatic stop, the user can recognize the automatic stop by a warning display or a warning sound.
[0016]
By the way, it is ideal if any printing pattern can be printed at the maximum speed and the printed paper can be sufficiently dried by the ink drying system. However, for that purpose, it is necessary to increase the capacity of the ink drying system sufficiently, which is not practical.
[0017]
Accordingly, in the first and second inventions of the present application, preferably, information on the printing speed set in the printing machine main body is received from the printing machine main body, and the conveying means conveys the printed paper in synchronization with the printing speed. The apparatus further includes transport speed control means for changing the transport speed to be performed.
[0018]
According to the above configuration, the slower the printing speed set in the printing machine body, the slower the transport speed of printed paper in the ink drying system. When the ink drying is insufficient, if the printing speed set for the printer is slowed down, the transport speed of the printed paper in the ink drying system will also be automatically slowed down, and the printed paper will be in the ink drying system. Longer time to stay in. Thereby, it is possible to easily dry the ink of the printed paper sufficiently.
[0019]
The second invention of the present application further includes a temperature detecting means for detecting the temperature of the printed paper in the vicinity of the printed paper discharge section, and the voltage application based on the temperature of the printed paper detected by the temperature detecting means. Voltage output control means for controlling the high-frequency voltage applied to each electrode by the means.
[0020]
In the above configuration, preferably, the temperature of the printing surface of the printed paper is detected. Preferably, the temperature is detected without contacting the printed paper.
[0021]
According to the above configuration, the temperature of the printed paper is detected after completion of ink drying or just before completion. When the detected temperature is lower than the appropriate range, the ink on the printed paper is insufficiently dried. For example, the high-frequency voltage applied to the electrode is increased to further dry the paper. On the other hand, when the detected temperature is higher than the appropriate range, the printed paper is excessively dried, so the high frequency voltage is reduced to suppress drying. Thereby, a stable dry state can always be obtained.
[0022]
In the first and second inventions of the present application, preferably, the frequency of the high-frequency voltage applied to each electrode by the voltage applying means is approximately 40 MHz or less. More preferably, it is below the 40 MHz band which is the ISM band.
[0023]
Industrially allocated frequencies in the Radio Law are 13.56, 27.12, 40.68, (40.46, 41.41), and 2450 MHz. In general, the higher the frequency within the range, the more the same dryness. The high frequency voltage applied to obtain the capability is small. However, considering the stability of the oscillation circuit and the influence on the paper as the base material, the upper limit is practically the 40 MHz band.
[0024]
In the first and second inventions of the present application, preferably, the ink of the printed paper to be forcibly dried is an emulsion ink in which a thermosetting resin is dispersed in at least an aqueous phase.
[0025]
Heat generation due to dielectric heating due to application of high-frequency voltage is the water phase of the oil phase and water phase of the ink. Therefore, if the thermosetting resin is dispersed in the heat generating water phase, the thermosetting resin is efficiently Can be heated. That is, as the temperature of the aqueous phase rises, the thermosetting resin component in the ink is cured, and then the aqueous phase evaporates, enclosing the oil phase in the cured resin phase, and between the ink and the paper surface. Bonding can be promoted .
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an ink drying system of a stencil printing machine according to an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the ink drying system 16 is an optional system for the stencil printing machine 10 and is disposed between the printing machine main body 12 and the paper tray 14. The printing machine main body 12 has a printing drum 20 for printing on paper, and a paper discharge belt 22 for discharging the printed paper. The ink drying system 16 includes a transport belt 24 that transports printed paper discharged from the printing machine main body 12 and discharges the printed paper to the paper receiving tray 14. The printed paper printed by the printing machine main body 12 is conveyed with its printing surface facing up, and is forcibly dried in the ink drying system 16 and then discharged to the paper tray 14. The printed paper 11 discharged from the ink drying system 16 falls with the leading end hitting the stop guide plate 15 and is stacked on the paper receiving tray 14.
[0027]
The ink drying system 16 includes a paper passage sensor 40, a transport belt 24, a blower fan 44, an electrode 30, and a temperature sensor 42, as shown in the main part configuration diagram of FIG. 2.
[0028]
The paper passage sensor 40 is a transmissive sensor provided on the high-frequency dryer side, and includes a light emitting unit 40b and a light receiving unit 40a across the paper conveyance path, and detects the arrival of printed paper into the ink drying system 16. Can be done. Note that another type of paper passing sensor 40, for example, a reflective sensor may be used.
[0029]
As shown by arrow A, the upper portion 24a of the conveyor belt 24 moves from the printing press main body 12 side to the paper tray 14 side, and the lower portion 24b moves in the reverse direction. The printed paper 11 is placed on the upper portion 24a of the transport belt 24, and is transported from the printer main body 12 side to the paper tray 14 side with its printing surface facing up.
[0030]
The blowing fan 44 is disposed above the conveying belt 24, blows air downward as indicated by an arrow B, blows the printed paper 11 onto the upper portion 24a of the conveying belt 24, and stably conveys the printed paper 11. To be.
[0031]
An electrode 30 is disposed directly below the upper portion 24 a of the conveyor belt 24. In the electrode 30, positive electrodes 31 a and negative electrodes 31 b are alternately arranged in the paper transport direction A. Each of the electrodes 31a and 31b extends in a direction crossing the sheet conveyance path, as shown in the plan view of the main part of FIG. 3, and a high frequency voltage is applied by the oscillating unit 32 including an oscillating circuit.
[0032]
As a result, an electric field that periodically changes is formed above the transport belt 24, and the printed paper 11 passes through the electric field. Under the influence of this electric field change, the printed paper causes rotational movement of the ink portion on the printed surface, particularly water molecules in the ink, and promotes heat generation due to dielectric loss, thereby heating the ink portion. The paper itself has a low water molecule content and hardly generates heat due to dielectric loss, so it is not heated directly. That is, it is possible to select only the ink on the printing surface of the printed paper 11 and forcibly heat it in a short time.
[0033]
For example, a sine wave voltage of about 40 MHz is applied to the electrode 30. The higher the frequency, the better the ink can be heated and dried in a short time. In practice, however, considering the safety of the oscillation circuit of the oscillation unit 32 and the fact that the paper itself does not generate heat, about 40 MHz is practical. It becomes a limit.
[0034]
The temperature sensor 42 is an infrared temperature sensor provided at the discharge port of the high frequency dryer on the paper tray 14 side, and measures the temperature of the printed surface of the printed paper passing thereunder in a non-contact manner. Based on the measurement result, control is performed so that the printed paper 11 is in an optimal heating / drying state.
[0035]
The ink drying system 16 is substantially sealed by an exterior 17 made of a metal material, for example, an aluminum plate, and prevents electromagnetic waves radiated from the electrode 30 to which a high frequency voltage is applied from leaking into the space. An upper cover 17a that covers an opening (not shown) is provided on the upper portion of the exterior 17, and when the upper cover 17a is opened as indicated by an arrow C, the inside can be accessed.
[0036]
FIG. 4 is a control block diagram.
[0037]
The control unit 50 on the printing machine main body 12 side has an operation panel 51 for setting a printing speed and the like, a communication interface 54 for communicating with the ink drying system 16 side, a program, and the like to a CPU 52 that controls the printing machine main body 12. A ROM 56 for storing data and a RAM 58 for temporarily storing data are connected.
[0038]
The control unit 60 of the ink drying system 16 temporarily stores data in a CPU 62 that controls the ink drying system 16, a communication interface 64 for communicating with the printer main body 12 side, a ROM 66 that stores programs, and the like. RAM 68, operation panel 70 used to adjust the high-frequency voltage level when the ink is not dry, transport motor 74 that drives transport belt 24, encoder 76 that detects the rotation of transport motor 74, blowing fan 44, and paper passage sensor 40 The upper cover / interlock switch 78 for detecting the opening / closing of the upper cover 17a provided on the upper portion of the exterior 17, the temperature sensor 42, the oscillation unit 32 for applying a high frequency voltage to the electrode 30, the CPU 62 and the oscillation unit 32 are supplied with power. Power supply unit 80 and the power supply voltage supplied to the oscillation unit 32 A tuner section 82 to node is connected. The CPU 62 communicates with the CPU 52 on the printing machine main body 12 side so as to drive the conveyance belt 24 at a speed corresponding to the printing speed set on the operation panel 51 (the faster the printing speed, the slower the slower the printing speed). The rotational speed of the transport motor 74 is controlled.
[0039]
The controller 60 of the ink drying system 16 operates as shown in the flowchart of FIG.
[0040]
That is, it waits for the printed paper 11 to pass just below the temperature sensor 42 (NO in # 12). If the printed paper 11 passes directly below the temperature sensor 42 (YES in # 12), the surface temperature of the printed paper 11 dried at high frequency is measured (# 14). Note that the transport position of the printed paper is calculated based on the outputs of the paper passage sensor 40 and the encoder 76.
[0041]
If the measured surface temperature of the printed paper 11 is 55 ° C. or lower (YES in # 16), a power-up process is performed to increase the dry output by a predetermined value. For example, the peak value (voltage amplitude) of the high frequency voltage applied to the electrode 30 is increased by 5% from the reference value.
[0042]
If the measured surface temperature of the printed paper 11 is not 55 ° C. or lower (NO in # 16), it is determined whether it is 60 ° C. or higher (# 20). If it is 60 ° C or higher (YES in # 20), a power-down process is performed to reduce the drying output by a predetermined value. For example, the peak value of the high frequency voltage applied to the electrode 30 is made 5% smaller than the reference value. If it is not 60 ° C or higher (NO in # 20), the drying output is left as it is.
[0043]
Thereby, the surface temperature of the printed paper 11 can be maintained at approximately 55 to 60 ° C. Therefore, it is possible to prevent the show-through that occurs because the ink is not sufficiently dried due to insufficient heating. In addition, it is possible to prevent the paper from being heated due to overheating of the ink and causing the paper to wavy.
[0044]
By the way, it is an aqueous phase having a high dielectric loss coefficient among the oil phase and the aqueous phase of ink that generates heat by dielectric heating due to application of a high-frequency voltage. When the emulsion ink in which the thermosetting resin is dispersed is used, the thermosetting resin can be efficiently heated by dispersing the thermosetting resin in the water phase that generates heat. That is, as the temperature of the aqueous phase rises, the thermosetting resin component in the ink is cured, and then the aqueous phase evaporates, enclosing the oil phase in the cured resin phase, and between the ink and the paper surface. Bonding can be promoted.
[0045]
Accordingly, when the paper printed using the emulsion ink in which the thermosetting resin is dispersed is forcibly dried by the ink drying system 16, the thermosetting resin is preferably dispersed at least in the water phase of the ink. .
[0046]
When the ink drying system 16 described above is used, the ink can be dried in a short time without heating the paper as much as possible.
[0047]
In addition, this invention is not limited to the said embodiment, It can implement in another various aspect. For example, the frequency of the high-frequency voltage applied to the electrode may be controlled instead of the peak value.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of an application example of an ink drying system according to an embodiment of the present invention.
FIG. 2 is a main part configuration diagram of the ink drying system of FIG. 1;
3 is a plan view of an essential part of the ink drying system of FIG. 1. FIG.
FIG. 4 is a control block diagram of the ink drying system of FIG. 1;
FIG. 5 is an operation flowchart of the ink drying system of FIG. 1;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Stencil printing machine 11 Printed paper 12 Printer main body 14 Paper receiving stand 15 Stop guide plate 16 Ink drying system 17 Exterior 17a Upper cover 20 Printing drum 22 Paper discharge belt 24 Conveying belt 24a Upper part 24b Lower part 30 Electrode 31a Positive Electrode 31b Negative electrode 32 Oscillating unit 40 Paper passage sensor 40a Light receiving unit 40b Light emitting unit 42 Temperature sensor 44 Blowing fan 50 Control unit 51 Operation panel 52 CPU
54 Communication interface 56 ROM
58 RAM
60 control unit 62 CPU
64 Communication interface 66 ROM
68 RAM
70 Operation panel 74 Conveyance motor 76 Encoder 78 Upper cover / interlock switch 80 Power supply 82 Tuner A Paper conveyance direction B Air blowing direction C Upper cover opening direction

Claims (6)

Printed paper that is placed between the printer body and the paper cradle and printed by the printer body is transported to the paper cradle with its printing surface facing up, and ink on the printed paper is transported during the transport. An ink drying system for a stencil printing machine, forcibly drying,
Transport means for supporting and transporting the lower surface of the printed paper;
A pair or two or more pairs of electrodes, which are alternately arranged in positive and negative directions in the transport direction of the printed paper along the transport path for transporting the printed paper by the transport means, each extending in a direction crossing the transport path; ,
Voltage applying means for applying a high frequency voltage to each electrode ;
An exterior that is configured using a metal material, substantially seals at least each of the electrodes and the transport path of the ink drying system, and includes an opening / closing portion that covers the interior in a releasable manner;
Open / close detecting means for detecting opening / closing of the open / close unit;
Voltage application stopping means for stopping the application of the high-frequency voltage to each electrode by the voltage applying means when the open / close detecting means detects that the opening / closing portion is open;
An ink drying system for a stencil printing machine , comprising: warning means for issuing a warning to a user when the application of high-frequency voltage to each electrode is stopped by the voltage application stopping means . Printed paper that is placed between the printer body and the paper cradle and printed by the printer body is transported to the paper cradle with its printing surface facing up, and ink on the printed paper is transported during the transport. An ink drying system for a stencil printing machine, forcibly drying,
Transport means for supporting and transporting the lower surface of the printed paper;
A pair or two or more pairs of electrodes, which are alternately arranged in positive and negative directions in the transport direction of the printed paper along the transport path for transporting the printed paper by the transport means, each extending in a direction crossing the transport path; ,
Voltage applying means for applying a high frequency voltage to each electrode ;
A temperature detecting means for detecting the temperature of the printed paper after ink drying, which is disposed at the high frequency dryer discharge unit of the printed paper;
Voltage output control means for controlling the high-frequency voltage applied to each electrode by the voltage application means based on the temperature of the printed paper after ink drying detected by the temperature detection means , Ink drying system for stencil printing machines. The ink drying system for a stencil printing machine according to claim 1 or 2 , wherein a blowing fan for blowing air downward is provided above a conveying path for conveying the printed paper by the conveying means. The apparatus further includes a conveyance speed control unit that receives information on the printing speed set in the printing machine main body from the printing machine main body and changes the conveyance speed at which the conveyance unit conveys the printed paper in synchronization with the printing speed The ink drying system of a stencil printing machine according to claim 1 or 2 , characterized in that 3. The ink drying system for a stencil printing machine according to claim 1, wherein the frequency of the high-frequency voltage applied to each electrode by the voltage applying means is approximately 40 MHz or less. The ink drying system of a stencil printing machine according to claim 1 or 2, wherein the ink of the printed paper to be forcibly dried is an emulsion ink in which a thermosetting resin is dispersed in at least an aqueous phase. .

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