JP2017119386A - Dryer, image forming device, drying method and control program for dryer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent overheating of liquid including an electrical conductive body.SOLUTION: A dryer 14 includes: a heating section 101 for heating liquid by applying an alternating electric field to liquid discharged to a medium 21; a detection section 102 for detecting a temperature of liquid including an electrical conductive body; and a control section 103 for controlling the alternating electric field based on the detected temperature so that the temperature of the liquid including the electrical conductive body does not exceed an upper limit value. The control section 103 stops generation of the alternating electric field when the temperature reaches equal to or higher than a first threshold value that is lower than the upper limit value, and starts the generation of the alternating electric field when the temperature reaches equal to or lower than a second threshold value that is lower than the first threshold value.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a drying apparatus, an image forming apparatus, a drying method, and a control program for the drying apparatus.

  2. Description of the Related Art An image forming apparatus such as an ink jet printer uses a drying device that dries a liquid discharged on a medium such as printing paper by using high frequency dielectric heating. High-frequency dielectric heating is a method of heating an object by applying a high-frequency AC electric field to the object. Thereby, the liquid can be dried in a non-contact state.

  For example, for the purpose of reducing damage, curling, cockling, and the like of paper as a printing medium, infrared radiation having a wavelength of 7 μm or more, which is frequently absorbed by paper, is suppressed, and the absorption wavelength band of water is 2. A drying device that radiates only infrared light of 5 μm to 3.5 μm is disclosed (Patent Document 1).

  When high-frequency dielectric heating is performed on black ink, a solvent such as water contained in the ink evaporates, and thereafter carbon black contained as a pigment remains. Since carbon black acts as a conductor, if a similar alternating magnetic field is continuously applied even after evaporation of the solvent, the carbon black may be overheated. Therefore, there is a possibility that problems such as blistering and scorching may occur in the black ink printing region. Such a problem is not limited to black ink containing carbon black, but may occur in various situations in which a liquid containing a conductor is dried using high-frequency dielectric heating.

  This invention is made | formed in view of the above, Comprising: It aims at preventing the excessive heating of the liquid containing a conductor.

  In order to solve the above-described problems and achieve the object, the present invention provides a heating unit that heats the liquid by applying an alternating electric field to the liquid discharged to the medium, and a temperature of the liquid including a conductor. A drying apparatus comprising: a detection unit that detects; and a control unit that controls the AC electric field so that a temperature of the liquid including the conductor does not exceed an upper limit value based on the detected temperature.

  According to the present invention, it is possible to prevent overheating of a liquid containing a conductor.

FIG. 1 is a diagram illustrating a schematic configuration of an image forming apparatus according to the first embodiment. FIG. 2 is a diagram illustrating a functional configuration of the drying apparatus according to the first embodiment. FIG. 3 is a diagram illustrating a specific configuration example of the drying apparatus according to the first embodiment. FIG. 4 is a diagram illustrating a specific configuration example of the drying apparatus according to the first embodiment. FIG. 5 is a diagram illustrating the configuration of the switch according to the first embodiment. FIG. 6 is a diagram illustrating a state in which the temperature of the black print pattern is detected by the line sensor according to the first embodiment. FIG. 7 is a diagram illustrating a control example of each switch by the CPU according to the first embodiment, and a temporal change example of the temperature detected by each line sensor. FIG. 8 is a diagram illustrating an operation example of each switch controlled by the CPU according to the first embodiment. FIG. 9 is a flowchart illustrating switch control by the CPU according to the first embodiment. FIG. 10 is a diagram illustrating a configuration of a drying apparatus according to the second embodiment. FIG. 11 is a diagram illustrating a control example of each high-frequency power supply by the CPU according to the second embodiment.

(First embodiment)
FIG. 1 is a diagram illustrating a schematic configuration of an image forming apparatus 1 according to the first embodiment. The image forming apparatus 1 includes a paper feeding device 11, a transport device 12, a liquid ejection device 13, a drying device 14, and a paper delivery device 15.

  The paper feeding device 11 is a device for feeding out the print medium 21. The paper feeding device 11 can be configured by using, for example, a mechanism for storing the print medium 21, a mechanism for unloading the stored print medium 21, and the like, but is not limited thereto. The print medium 21 is a sheet-like medium from which a liquid is discharged, and may be a well-known or new appropriate material and shape. In the present embodiment, an example in which roll paper is used as the print medium 21 is shown, but the print medium 21 is not limited to this.

  The transport device 12 is a device that transports the print medium 21 in a predetermined transport direction. The transport device 12 may be configured using, for example, a plurality of rollers, a belt wound around the rollers, a motor that rotates the rollers, and the like, but is not limited thereto.

  The liquid ejection device 13 is a device that ejects liquid onto the print medium 21. The liquid ejection device 13 may be configured using, for example, an ink tank that stores ink of each color, a liquid ejection head that ejects ink, an electronic control unit that controls the liquid ejection head, and the like, but is not limited thereto. The liquid ejection device 13 according to the present embodiment ejects a liquid containing a conductor. Examples of the conductor include carbon black and the like, but are not limited thereto. Examples of the liquid containing the conductor include black ink containing carbon black, but are not limited thereto.

  The drying device 14 is a device that dries the liquid discharged to the print medium 21 using high-frequency dielectric heating. The drying device 14 can be configured using, for example, a mechanism that generates a high-frequency AC electric field in the casing, a mechanism that detects the temperature of the liquid discharged to the print medium 21, and the like, but is not limited thereto. A specific configuration example of the drying device 14 will be described in detail later.

  The paper discharge device 15 is a device that discharges the print medium 21 dried by the drying device 14 to the outside of the image forming apparatus 1. The paper discharge device 15 includes, for example, a discharge port that opens to the outside of the image forming apparatus 1, a mechanism that conveys the dried print medium 21 to the discharge port, a mechanism that aligns the position of the print medium 21 discharged from the discharge port, and the like. However, the present invention is not limited to this.

  The print medium 21 is a medium to which liquid can adhere at least temporarily. Examples of the material of the print medium 21 include paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, and ceramics.

  The liquid ejected to the print medium 21 may be any liquid that can be attached to the print medium 21 at least temporarily, and is not limited to being ink. Examples of the substances contained in the liquid include, for example, solvents such as water and organic solvents, colorants such as pigments and dyes, solutions and suspensions containing functional materials such as polymerizable compounds, resins, and surfactants, An emulsion etc. are mentioned.

  FIG. 2 is a diagram illustrating a functional configuration of the drying apparatus 14 according to the first embodiment. The drying device 14 includes a heating unit 101, a detection unit 102, and a control unit 103.

  The heating unit 101 heats the liquid by applying a high-frequency AC electric field to the liquid discharged to the printing medium 21. As a result, a solvent such as water contained in the liquid is heated and evaporated by the action of high-frequency dielectric heating, and a pigment (dye) such as carbon black remains. The generation method of the alternating electric field, the application method to the liquid, and the like are not particularly limited, and the heating unit 101 may be configured using a known or new appropriate technique. For example, the heating unit 101 can be configured using an electrode pair including a pair of positive and negative electrodes that generate an AC electric field when a high-frequency AC voltage is applied. It is preferable that a plurality of such electrode pairs are arranged along the conveyance direction of the print medium 21 so that the generation of an alternating electric field can be controlled in each electrode pair. According to such a configuration, it is possible to appropriately adjust the temperature of the liquid while conveying the print medium 21.

  The detection unit 102 detects the temperature of the liquid containing the conductor discharged on the print medium 21. The detection method of the liquid containing a conductor, the detection method of temperature, etc. should not be specifically limited, The detection part 102 should just be comprised using a known or new appropriate method. For example, the detection unit 102 can be configured using a plurality of infrared line sensors or the like. Each line sensor scans the print medium 21 in a direction perpendicular to the conveyance direction of the print medium 21, and a plurality of line sensors are preferably arranged along the conveyance direction of the print medium 21. According to such a configuration, it is possible to accurately detect a change in the temperature of the liquid when the print medium 21 is conveyed.

  Based on the temperature detected by the detection unit 102, the control unit 103 controls the AC electric field generated in the heating unit 101 so that the temperature of the liquid containing the conductor does not exceed a predetermined upper limit value. The control method of the AC electric field is not particularly limited, and the control unit 103 may be configured using a known or new appropriate method. For example, the control unit 103 may be configured using a CPU (Central Processing Unit) controlled by a program, or may be configured by a combination of logic circuits.

  3 and 4 are diagrams illustrating a specific configuration example of the drying device 14 according to the first embodiment. In FIG. 3, a housing 31, a high frequency power supply 32, a matching unit 33, electrode pairs 34A to 34I, and line sensors 35A to 35I are shown. The casing 31, the high frequency power source 32, the matching unit 33, and the electrode pairs 34A to 34I constitute a part of the heating unit 101. The line sensors 35 </ b> A to 35 </ b> I constitute a part of the detection unit 102. Hereinafter, a black ink containing carbon black will be described as an example of the liquid containing a conductor.

  The casing 31 is a member that constitutes the outline of the drying device 14. The print medium 21 on which the ink has been ejected is carried into the housing 31, heated within the housing 31, and then carried out.

  The high frequency power supply 32 generates an AC voltage having a predetermined frequency. The matching unit 33 is a circuit that matches the output impedance on the high frequency power supply 32 side and the input impedance on the electrode pair 34A to 34I side. By the action of the matching unit 33, an AC voltage having a stable frequency is applied to each of the electrode pairs 34A to 34I.

  Each electrode pair 34A-34I is comprised from a pair of positive electrode and negative electrode. The pitch L between all the positive and negative electrodes constituting the electrode pairs 34A to 34I is constant. Each electrode pair 34 </ b> A to 34 </ b> I generates an alternating electric field having a predetermined frequency between the positive electrode and the negative electrode in response to application of the alternating voltage. In the present example, nine electrode pairs 34 </ b> A to 34 </ b> I are arranged along the transport direction of the print medium 21 on the bottom surface of the casing 31 (below the print medium 21). Each electrode pair 34 </ b> A to 34 </ b> I is connected to the output terminal of the matching unit 33.

  The line sensors 35 </ b> A to 35 </ b> I are infrared sensors that scan the print medium 21 in a direction perpendicular to the conveyance direction of the print medium 21 (width direction of the print medium 21). The line sensors 35 </ b> A to 35 </ b> I detect the temperature of ink containing carbon black ejected onto the print medium 21. In this example, nine line sensors 35 </ b> A to 35 </ b> I are arranged along the conveyance direction of the print medium 21 on the upper surface portion of the housing 31 (upper side of the print medium 21). For example, the line sensors 35 </ b> A to 35 </ b> I may be installed outside the housing 31 so that a predetermined range can be scanned through a hole formed in the upper surface of the housing 31. Each line sensor 35A-35I is installed at equal intervals so as to correspond to each electrode pair 34A-34I.

  In FIG. 4, a CPU 41 and switches 42A to 42J are shown. The CPU 41 and the switches 42 </ b> A to 42 </ b> J constitute a part of the control unit 103.

  The CPU 41 is a device including a processor controlled by a control program stored in a memory. CPU41 outputs the control signal which controls each switch 42A-42J separately based on the detection signal (temperature of black ink) of each line sensor 35A-35I.

  The switches 42 </ b> A to 42 </ b> J are installed on the wiring that connects the matching unit 33 and each electrode (positive electrode and negative electrode). In this example, ten switches 42A to 42J are installed so as to correspond to the positive electrodes and the negative electrodes constituting the nine electrode pairs 34A to 34I. Each of the switches 42A to 42J switches start / stop of voltage supply to each electrode in accordance with a control signal from the CPU 41.

  FIG. 5 is a diagram illustrating the configuration of the switches 42A to 42J according to the first embodiment. The switches 42A to 42J include SW_A43 and SW_B44. The SW_A 43 includes a first node 45, a second node 46, and a third node 47. The SW_B 44 includes a first node 45 and a third node 47. The first node 45 is connected to the output of the matching unit 33. The second node 46 is connected to each electrode (positive electrode or negative electrode). The third node 47 is connected to GND. The SW_A 43 connects the second node 46 exclusively with either the first node 45 or the third node 47. The SW_B 44 switches whether the first node 45 and the third node 47 are connected. In the figure, the left state is an ON state (a state where a voltage is applied to the electrode) 48, and the right state is an OFF state (a state where no voltage is applied to the electrode) 49.

  FIG. 6 is a diagram illustrating a state in which the temperature of the black print pattern 51 is detected by the line sensors 35A to 35I according to the first embodiment. The black print pattern 51 is an example of a print pattern that appears with ink containing carbon black. The black print pattern 51 moves from right to left in the figure at the conveyance speed V of the print medium 21. In the figure, scanning ranges 55A to 55I corresponding to the line sensors 35A to 35I are shown. The scanning ranges 55A to 55I are arranged in parallel with each other at equal intervals along the conveyance direction of the print medium 21. The temperature of the black print pattern 51 is detected in each of the scanning ranges 55A to 55I.

  A state 61 indicates a state in which the temperature of the black print pattern 51 is detected by the first line sensor 35A at time t0. A state 62 indicates a state in which the temperature of the black print pattern 51 is detected by the second line sensor 35B at time t0 + Δ. Δ indicates an elapsed time from the first scanning range 55A to the second scanning range 55B. If the transport speed V is constant, any elapsed time from the nth scanning range to the (n + 1) th scanning range is equal to Δ. A state 63 indicates a state in which the temperature of the black print pattern 51 is detected by the third line sensor 35C at time t0 + 2Δ. A state 64 indicates a state in which the temperature of the black print pattern 51 is detected by the fourth line sensor 35D at time t0 + 3Δ. A state 65 indicates a state in which the temperature of the black print pattern 51 is detected by the eighth line sensor 35H at time t0 + 7Δ. A state 66 indicates a state in which the temperature of the black print pattern 51 is detected by the ninth line sensor 35I at time t0 + 8Δ. In FIG. 6, detection by the fifth to seventh line sensors 35E to 35G at time t0 + 4Δ to 6Δ is omitted.

  FIG. 7 is a diagram illustrating an example of control of the switches 42A to 42J by the CPU 41 according to the first embodiment and an example of a change over time of the temperature detected by the line sensors 35A to 35I. FIG. 8 is a diagram illustrating an operation example of each of the switches 42A to 42J controlled by the CPU 41 according to the first embodiment.

  The CPU 41 controls the switches 42A to 42J so that the temperature of the black print pattern 51 does not exceed the upper limit value T0. When the temperature detected by each of the line sensors 35A to 35I becomes equal to or higher than the first threshold value T1, the CPU 41 sets the electrode pairs 34A to 34A located on the downstream side in the transport direction of the print medium 21 from the detected temperature. The switches 42A to 42J corresponding to 34I are turned OFF. The first threshold T1 is a temperature lower than the upper limit value T0. In addition, when the temperature detected by each of the line sensors 35 </ b> A to 35 </ b> I is equal to or lower than the second threshold value T <b> 2, the CPU 41 sets an electrode pair positioned downstream in the transport direction of the print medium 21 from the detected temperature. The switches 42A to 42J corresponding to 34A to 34I are turned ON. The second threshold T2 is a temperature lower than the first threshold T1.

  FIG. 7 shows that the detected temperature is temporarily maintained at about 100 ° C. near time t0. This is because water contained in the ink evaporates.

  Thereafter, the temperatures detected by the second and third line sensors 35B, 35C (S2, S3) from time t0 + Δ to time t0 + 2Δ are both lower than the first threshold T1. Further, at this time, the detected temperature has not yet exceeded the first threshold value T1. Therefore, any of the switches 42A to 42J (SW1 to SW10) is ON.

  Thereafter, at time t0 + 3Δ, it is detected by the fourth line sensor 35D (S4) that the detected temperature has become equal to or higher than the first threshold value T1. Accordingly, the fifth and sixth switches 42E and 42F (SW5 and SW6) corresponding to the fifth electrode pair 34E located on the downstream side of the fourth line sensor 35D are turned OFF.

  Thereafter, the temperatures detected by the fifth to seventh line sensors 35E to 35G (S5 to S7) from time t0 + 4Δ to time t0 + 6Δ are all higher than the second threshold T2. In addition, the detected temperature has not become the second threshold value T2 or less at this time. Therefore, the sixth and seventh switches 42F and 42G (SW6 and SW7) corresponding to the sixth electrode pair 34F positioned on the downstream side of the fifth line sensor 35E are positioned on the downstream side of the sixth line sensor 35F. The seventh and eighth switches 42G and 42H (SW7 and SW8) corresponding to the seventh electrode pair 34G and the eighth electrode pair 34H corresponding to the eighth electrode pair 34H located on the downstream side of the seventh line sensor 35G. The ninth switches 42H and 42I (SW8 and SW9) are sequentially turned off.

  Thereafter, at time t0 + 7Δ, the eighth line sensor 35H (S8) detects that the detected temperature has become equal to or lower than the second threshold value T2. In response to this, the ninth and tenth switches 42I, 42J (SW9, SW10) corresponding to the ninth electrode pair 34I located on the downstream side of the eighth line sensor 35H are turned ON.

  The upper limit value T0 may be, for example, a paper ignition temperature (and 300 ° C.). The difference between the upper limit value T0 and the first threshold value T1 is preferably larger than the maximum temperature difference that can occur at the pitch L (maximum temperature rise by one electrode pair 34A to 34I). Thereby, it is possible to reliably prevent the temperature of the black print pattern 51 from exceeding the upper limit value T0. Similarly, the difference between the first threshold value T1 and the second threshold value T2 is preferably larger than the maximum temperature difference that can occur at the pitch L.

The upper limit value T0 and the first threshold value T1 are preferably set so that, for example, the following formula (1) is satisfied.
L / v <(T0−T1) / Tα (1)
In the above formula (1), L “m” is the pitch between the positive electrode and the negative electrode, v [m / s] is the conveyance speed of the printing medium 21, T0 [° C.] is the upper limit value, and T1 [° C.] is The first threshold value Tα [° C./s] indicates a carbon temperature increase coefficient.

  FIG. 9 is a flowchart showing control of the switches 42A to 42J by the CPU 41 according to the first embodiment. When the CPU 41 reads the detected temperature TS [i] of the i-th line sensors 35A to 35I (S101), the CPU 41 determines whether or not the detected temperature TS [i] is larger than the first threshold T1 (S102).

  When TS [i]> T1 is satisfied (S102: Yes), the CPU 41 sets the value of the flag FS indicating the ON / OFF state of the switches 42A to 42J to the value “1” indicating the OFF state (S103). Thereafter, the CPU 41 switches the switches 42A to 42J corresponding to the (i + 1) th electrode pairs 34A to 34I from the ON state to the OFF state (S104), and resets the holding elapsed time in the OFF state (S105). The hold elapsed time in the OFF state is used as a parameter for detecting the occurrence of an error. Although not described in detail here, when the retention elapsed time reaches a threshold value, a warning may be displayed, the entire operation may be stopped, or the ON state may be forcibly set.

  Thereafter, the CPU 41 determines whether or not the value i indicating the number of the line sensors 35A to 35I is “9” (S106). If i = 9 (S106: Yes), this routine is terminated. If i = 9 is not satisfied (S106: No), the value i is incremented by 1 (S107), and the process returns to step S101.

  On the other hand, when TS [i]> T1 is not satisfied (S102: No), the CPU 41 determines whether or not the value of the flag FS is “1” (S111). When FS = 1 (S111: Yes), that is, when the flag FS indicates the OFF state, the CPU 41 determines whether or not the detected temperature TS [i] is smaller than the second threshold T2 ( S112).

  When TS [i] <T2 (S112: Yes), the CPU 41 switches the switches 42A to 42J corresponding to the (i + 1) th electrode pair 34A to 34I from the OFF state to the ON state (S113), and the value of the flag FS. Is set to a value “0” indicating the ON state (S114). Thereafter, step S106 is executed.

  If FS is not 1 in step S111 (No), that is, if the detected temperature TS [i] is not greater than the first threshold T1, and the flag FS indicates the ON state, the switch 42A Step S106 is executed without switching to 42J (while maintaining the ON state).

  If TS [i] <T2 is not satisfied in step S112 (No), that is, if the flag FS indicates the OFF state and the detected temperature TS [i] is not smaller than the second threshold T2, Then, step S106 is executed without switching the switches 42A to 42J (while maintaining the OFF state).

  With the above processing, the switches 42A to 42J positioned downstream of the detection positions can be appropriately switched according to the detected temperatures of the line sensors 35A to 35I. Thereby, it is possible to appropriately control the alternating electric field generated from each of the electrode pairs 34A to 34I, and it is possible to prevent overheating of the liquid containing the conductor.

(Second Embodiment)
In the following, the second embodiment will be described with reference to the drawings. The same or similar parts as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted. There is a case.

  FIG. 10 is a diagram illustrating a configuration of the drying device 24 according to the second embodiment. In the present embodiment, a plurality of high-frequency power sources 32A to 32E and a plurality of matching units 33A to 33E are installed so as to correspond to a pair of positive and negative electrodes.

  The first high frequency power supply 32A and the first matching unit 33A apply a voltage to the positive electrode and the negative electrode that constitute the first electrode pair 34A. The negative electrode constituting the first electrode pair 34A also constitutes the second electrode pair 34B.

  The second high frequency power supply 32B and the second matching unit 33B apply a voltage to the positive electrode and the negative electrode that constitute the third electrode pair 34C. The positive electrode constituting the third electrode pair 34C also constitutes the second electrode pair 34B, and the negative electrode constituting the third electrode pair 34C constitutes the fourth electrode pair 34D.

  The third high-frequency power source 32C and the third matching unit 33C apply a voltage to the positive electrode and the negative electrode that constitute the fifth electrode pair 34E. The positive electrode constituting the fifth electrode pair 34E constitutes the fourth electrode pair 34D, and the negative electrode constituting the fifth electrode pair 34E constitutes the sixth electrode pair 34F.

  The fourth high-frequency power source 32D and the fourth matching unit 33D apply a voltage to the positive electrode and the negative electrode constituting the seventh electrode pair 34G. The positive electrode constituting the seventh electrode pair 34G also constitutes the sixth electrode pair 34F, and the negative electrode constituting the seventh electrode pair 34G constitutes the eighth electrode pair 34H.

  The fifth high frequency power supply 32E and the fifth matching unit 33E apply a voltage to the positive electrode and the negative electrode constituting the ninth electrode pair 34I. The positive electrode constituting the ninth electrode pair 34I also constitutes the eighth electrode pair 34H.

  With the above configuration, the AC electric fields of the electrode pairs 34A to 34I can be controlled by controlling the outputs of the high frequency power sources 32A to 32E. Further, by configuring as shown in FIG. 10, one high frequency power source (for example, the second high frequency power source 32B) can be shared by a plurality of electrode pairs (for example, the second to fourth electrode pairs 34B to 34D). .

  Based on the detection signals from the line sensors 35A to 35I, the CPU 41 outputs the high frequency power sources 32A to 32E so that the temperature of the black print pattern 51 does not exceed the upper limit value T0, as in the first embodiment. To control.

  FIG. 11 is a diagram illustrating a control example of the high-frequency power sources 32A to 32E by the CPU 41 according to the second embodiment. This example shows a case where the temperature of the black print pattern 51 detected by the fourth line sensor 35D exceeds the first threshold value T1. In this case, the CPU 41 controls the third high-frequency power source 32C so that no voltage is applied to the fifth electrode pair 34E disposed on the downstream side of the fourth line sensor 35D (fourth scanning range 55D). Specifically, the third high-frequency power supply 32C is controlled so that the input terminals of the positive electrode and the negative electrode constituting the fifth electrode pair 34E have the GND potential.

  Also in the present embodiment, as in the first embodiment, the AC electric field generated from each electrode pair 34A to 34I can be appropriately controlled according to the detected temperature of each line sensor 35A to 35I. Further, overheating of the liquid containing the conductor can be prevented. In addition, according to the present embodiment, it is not necessary to provide a plurality of switches so as to correspond to all of the positive electrode and the negative electrode, so that the circuit can be simplified.

  Although the embodiments of the present invention have been described above, the above-described embodiments are presented as examples and are not intended to limit the scope of the invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. This embodiment and its modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 11 Paper supply apparatus 12 Conveyance apparatus 13 Liquid discharge apparatus 14,24 Drying apparatus 15 Paper discharge apparatus 21 Print medium 31 Case 32, 32A-32E High frequency power supply 33, 33A-33E Matching device 34A-34I Electrode pair 35A ~ 35I Line sensor 41 CPU
42A to 42J Switch 43 SW_A
44 SW_B
45 1st node 46 2nd node 47 3rd node 48 ON state 49 OFF state 51 Black printing pattern 55A-55I Scanning range 101 Heating part 102 Detection part 103 Control part

Japanese Patent Laying-Open No. 2015-044351

Claims (13)

A heating unit for heating the liquid by applying an alternating electric field to the liquid discharged to the medium;
A detection unit for detecting the temperature of the liquid containing a conductor;
Based on the detected temperature, a control unit that controls the AC electric field so that the temperature of the liquid including the conductor does not exceed an upper limit value;
A drying apparatus comprising: The heating unit includes a plurality of electrode pairs including a pair of positive and negative electrodes that generate the alternating electric field,
The detection unit includes a plurality of line sensors that scan the medium in a direction perpendicular to a conveyance direction of the medium,
The plurality of electrode pairs and the plurality of line sensors are arranged along the transport direction and corresponding to each other,
The control unit is disposed at a second position, which is a position downstream of the first position in the transport direction, based on the temperature detected by the line sensor disposed at the first position. Controlling the alternating electric field of the electrode pair;
The drying apparatus according to claim 1. The controller stops the generation of the AC electric field when the temperature becomes equal to or higher than a first threshold value lower than the upper limit value, and the temperature becomes equal to or lower than a second threshold value lower than the first threshold value. Sometimes start generating the AC electric field,
The drying apparatus according to claim 2. The pitch between the positive electrode and the negative electrode is constant,
The difference between the upper limit and the first threshold is greater than the maximum temperature difference of the temperatures that can occur at the pitch,
The drying apparatus according to claim 3. The difference between the first threshold and the second threshold is greater than the temperature difference;
The drying apparatus according to claim 4. The relationship of the following formula (1) is satisfied, where L is the pitch, v is the conveyance speed of the medium, T0 is the upper limit value, T1 is the first threshold value, and Tα is the carbon temperature increase coefficient. Or the drying apparatus of 5.
L / v <(T0−T1) / Tα (1) A high frequency power source for generating an alternating voltage applied to the positive electrode and the negative electrode;
A plurality of switches for controlling the application of the alternating voltage for each of the positive electrode and the negative electrode;
Further comprising
The control unit controls the switches based on the temperatures detected by the line sensors.
The drying apparatus according to any one of claims 2 to 6. A plurality of high-frequency power supplies that are arranged to correspond to the pair of the positive electrode and the negative electrode, generating an alternating voltage applied to the electrode pair;
Further comprising
The control unit controls the high-frequency power sources based on the temperatures detected by the line sensors.
The drying apparatus according to any one of claims 2 to 6. The conductor is carbon black.
The drying apparatus according to any one of claims 1 to 8. The liquid is black ink.
The drying apparatus according to claim 9. A liquid ejection device for ejecting the liquid onto the medium;
The drying apparatus according to any one of claims 1 to 10,
An image forming apparatus comprising: Heating the liquid by applying an alternating electric field to the liquid discharged to the medium;
Detecting the temperature of the liquid containing a conductor;
Controlling the alternating electric field based on the detected temperature so that the temperature of the liquid containing the conductor does not exceed an upper limit;
Including a drying method. A heating unit for heating the liquid by applying an alternating electric field to the liquid discharged to the medium;
A detection unit for detecting the temperature of the liquid containing a conductor;
A program for controlling a processor for controlling a drying apparatus comprising:
In the processor,
A process for controlling the AC electric field based on the detected temperature so that the temperature of the liquid containing the conductor does not exceed an upper limit;
A control program for a drying apparatus that executes

Images