Inkjet recording apparatus and inkjet recording apparatus system

Abstract

An inkjet recording apparatus (1) comprises: a printing head (200) that performs printing upon receiving a supply of ink; and a body (100) that includes a control device (15) and supplies ink to the printing head (200). The printing head (200) has a piezoelectric element (202), a charging electrode (203), a deflection electrode (204), and an auto phase sensor (206) in which a voltage corresponding to the amount of electric charge of ink particles is induced. The control device (15) is configured so as to be capable of operating the inkjet recording apparatus (1) while being alternately switched between: a printable mode in which an excitation signal having a high excitation voltage and a high excitation frequency is applied to the piezoelectric element (202); and an energy-saving mode in which an excitation signal having a low excitation voltage and a low excitation frequency is applied to the piezoelectric element (202).

Description

Inkjet recording apparatus and inkjet recording apparatus system

[0001] The present invention relates to an inkjet printing apparatus and an inkjet printing apparatus system.

[0002] In an inkjet recording device, ink pressurized by a supply pump is adjusted to a set pressure when it passes through a pressure reducing valve and is then sent to the nozzle. In an inkjet recording device, the ink is atomized by its own surface tension as it passes through the ink ejection holes in the orifice at the end of the nozzle. However, since ink does not atomize regularly, in order to print, it is necessary to constantly apply a constant, high-frequency excitation signal to the piezoelectric element inside the nozzle to atomize it regularly (particle size, atomization period).

[0003] In addition, inkjet recording devices charge ink particles during non-printing periods to find the timing (phase) that provides the best charging efficiency for the ink particles. The inkjet recording device is equipped with a sensor (autophase sensor) in the gutter that induces a voltage corresponding to the amount of charge on the ink particles. The inkjet recording device searches for a phase that allows normal charging based on the voltage induced in this sensor. By charging the ink particles at the phase that has been found, the inkjet recording device can maintain high print quality (see, for example, Patent Document 1).

[0004] If the voltage induced in the autophase sensor is lower than a predetermined voltage (threshold level voltage), the inkjet recording device determines that the ink particles cannot be collected in the gutter and cannot be formed into ink particles normally, and displays a confirmation message indicating that an abnormality has been detected.

[0005] Japanese Patent Application Laid-Open No. 2003-220707

[0006] Inkjet recording apparatuses are required to consume less power in order to reduce the environmental impact. The present invention has been made to solve the above-mentioned problem. That is, one of the objects of the present invention is to provide an inkjet recording apparatus and an inkjet recording apparatus system that can reduce power consumption.

[0007] In order to solve the above problems, the inkjet recording device of the present invention comprises a print head that receives a supply of ink and performs printing, and a main body that includes a control device and supplies the ink to the print head, wherein the print head has a piezoelectric element that converts the ink into ink particles, a charging electrode that charges the ink particles, a deflection electrode that deflects the charged ink particles, and an autophase sensor that induces a voltage according to the amount of charge of the ink particles, and the control device is configured to be able to switch between a printable mode in which a first excitation voltage and an excitation signal of a first excitation frequency are applied to the piezoelectric element, and an energy-saving mode in which a second excitation voltage lower than the first excitation voltage and an excitation signal of a second excitation frequency lower than the first excitation frequency are applied to the piezoelectric element.

[0008] The inkjet recording device system of the present invention is an inkjet recording device system comprising an inkjet recording device and a server communicably connected to the inkjet recording device via a network, wherein the inkjet recording device comprises a print head that receives a supply of ink and performs printing, and a main body that includes a control device and supplies the ink to the print head, wherein the print head has a piezoelectric element that converts the ink into ink particles, a charging electrode that charges the ink particles, a deflection electrode that deflects the charged ink particles, and an autophase sensor that induces a voltage according to the amount of charge of the ink particles, and the control device is configured to be able to switch between a printable mode in which a first excitation voltage and an excitation signal of a first excitation frequency are applied to the piezoelectric element, and an energy-saving mode in which a second excitation voltage lower than the first excitation voltage and an excitation signal of a second excitation frequency lower than the first excitation frequency are applied to the piezoelectric element.

[0009] According to the present invention, it is possible to reduce power consumption. Note that the effects described here are not necessarily limited to those described herein, and may be any of the effects described in this disclosure.

[0010] FIG. 1A is a diagram showing an example of the configuration of an inkjet recording apparatus system. FIG. 1B is a diagram illustrating an example of the hardware configuration of a server. FIG. 2 is a diagram showing the configuration of an inkjet recording apparatus. FIG. 3 is a diagram illustrating a phase search charging signal. FIG. 4 is a diagram showing a phase detection signal waveform (normal). FIG. 5 is a diagram showing a phase detection signal waveform (when ink particle formation is abnormal). FIG. 6 is a diagram showing a phase detection signal waveform (when ink particle collection fails). FIG. 7 is a schematic diagram showing the operating status when the inkjet recording apparatus is in pause mode. FIG. 8 is a schematic diagram showing the operating status when the inkjet recording apparatus is in printable mode. FIG. 9 is a schematic diagram showing the operating status when the inkjet recording apparatus is in energy saving mode. FIG. 10 is a diagram showing a control flow for setting the excitation frequency and excitation voltage of the excitation signal when the inkjet recording apparatus is in energy saving mode.

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that, in all drawings of the embodiment, the same or corresponding parts may be denoted by the same reference numerals. In the following description, a process will be described using a functional block as the subject. However, the subject of the process may be an MPU or an apparatus instead of a functional block. <<Embodiment>> FIG. 1A is a diagram showing the overall configuration of an inkjet recording system according to an embodiment of the present invention. As shown in FIG. 1A, the inkjet recording system includes an inkjet recording apparatus 1 and a server 2. The inkjet recording apparatus 1 and the server 2 are connected to each other via a communication line 3 (network) so that they can transmit and receive information. Note that, in this embodiment, an example will be described in which one inkjet recording apparatus 1 is connected to the server 2; however, multiple inkjet recording apparatuses 1 may be connected to the server 2. The inkjet recording apparatus 1 is installed, for example, on a production line in a factory where beverages, food, etc. are produced.

[0012] The production line is composed of multiple belt conveyors, which are transport devices, and each belt conveyor transports a printing target 4, such as a PET bottle filled with a beverage or a packaging container containing food. Note that, although Fig. 1A shows only two conveyors, a downstream conveyor 5a that transports the printing target 4 immediately before printing, and an upstream conveyor 5b adjacent to the downstream conveyor 5a on the upstream side in the transport direction, the number of belt conveyors is not limited to two.

[0013] A first printed material detection sensor 6a is installed near the downstream conveyor 5a, and a second printed material detection sensor 6b is installed near the upstream conveyor 5b. In addition, a first rotary encoder 7a is installed on the downstream conveyor 5a, and a second rotary encoder 7b is installed on the upstream conveyor 5b.

[0014] The first printed material detection sensor 6a is used to determine the printing timing, and when it detects that the print target 4 has reached a predetermined position on the downstream conveyor 5a, it sends a detection signal to the control unit 15 as a trigger to start printing. The second printed material detection sensor 6b is used to determine switching between a printable mode (normal mode) and an energy-saving mode (described later). When it detects that the print target 4 has reached a predetermined position on the upstream conveyor 5b, it sends a detection signal to the control unit 15, indicating that the print target 4 is ready to be transported. In this embodiment, the first printed material detection sensor 6a and the second printed material detection sensor 6b are installed on different belt conveyors, but they may also be installed on the same belt conveyor. In that case, the first printed material detection sensor 6a is installed downstream of the same belt conveyor, and the second printed material detection sensor 6b is installed upstream of the same belt conveyor.

[0015] The first rotary encoder 7a is used to determine the printing timing, and generates a pulse signal according to the transport speed of the downstream conveyor 5a (movement speed of the print object 4), and sends it to the control unit 15. The second rotary encoder 7b is used to determine switching between the normal mode and the energy saving mode described below, and generates a pulse signal according to the transport speed of the upstream conveyor 5b (movement speed of the print object 4), and sends it to the control unit 15. It is also possible to specify the printing timing and determine mode switching by having the print object detection sensor measure the light blocking time, without providing a rotary encoder.

[0016] Furthermore, the second printed matter detection sensor 6b and the second rotary encoder 7b may be installed on a belt conveyor upstream of the downstream conveyor 5a, and do not necessarily have to be installed on the upstream conveyor 5b adjacent to the downstream conveyor 5a.

[0017] The control unit 15 includes an MPU 101, which is a processor, a ROM 102, a RAM 103, and an interface (I / F) IF1, which includes a network interface and an input / output interface. The control unit 15 may also be referred to as a "control device." These components are connected to each other via a bus so that they can communicate with each other. The MPU 101 is a computing device that realizes the functions of the control unit 15 by reading and executing programs stored in the ROM 102. The configuration of the control unit 15 will be described in more detail later with reference to FIG. 2.

[0018] The operation display unit 14 displays information relating to the inkjet recording apparatus 1, an operation screen for inputting information, etc., and is operated by the user to input information. The operation display unit 14 is composed of an input panel 104 and a display device 105 (FIG. 2), which will be described later.

[0019] The server 2 periodically collects operational information from the inkjet recording apparatus 1. The operational information includes the model, operating time, and number of prints of the inkjet recording apparatus 1, as well as sensor data such as measured values ​​of each sensor installed in the inkjet recording apparatus 1. Note that the server 2 may collect the operational information indirectly from a computer (terminal device, not shown) connected to the inkjet recording apparatus 1, rather than directly from the inkjet recording apparatus 1.

[0020] 1B is a diagram showing an example of the hardware configuration of the server 2. As shown in FIG. 1B, the server 2 includes a CPU 2011, a ROM 2012, a RAM 2013, a non-volatile storage device (HDD) 2014 that can read and write data, a network interface 2015, an input / output interface 2016, and the like. These are connected to each other via a bus 2017 so as to be able to communicate with each other. Note that the server 2 may be made up of multiple servers, may be a virtual server, or may be made up of computer resources (servers, storage, etc.) on the cloud.

[0021] The CPU 2011 is a computing device that realizes various functions by loading various programs (not shown) stored in the ROM 2012 and / or HDD 2014 into the RAM 2013 and executing the programs loaded into the RAM 2013. As described above, the various programs executed by the CPU 2011 are loaded into the RAM 2013, and data used by the CPU 2011 when executing the various programs is temporarily stored in the RAM 2013. The ROM 2012 and / or HDD 2014 are non-volatile storage media that store various programs. The network interface 2015 is an interface for connecting the server 2 to the network NW1. The input / output interface 2016 is an interface for connecting to operating devices such as a keyboard and a mouse and a display (display device). At least a portion of the processing performed by the CPU 2011 when executing the programs may be executed by another computing device (e.g., hardware such as an ASIC or FPGA).

[0022] Fig. 2 is a diagram of an inkjet recording apparatus 1 (also referred to as "IJP") according to this embodiment. As shown in Fig. 2, the IJP comprises an IJP main body 100 and a print head 200. The print head 200 is installed so as to face the transport path of the print target 4 transported by a conveyor 300 of the production line.

[0023] The IJP main body 100 is provided with a control unit 15 that controls the operation of the print head 200, and this control unit 15 is composed of the following components, for example.

[0024] The IJP is equipped with a microcomputer (hereinafter referred to as MPU) 101 that controls the entire IJP, a read-only memory (ROM 102) that stores control programs and data necessary for the MPU 101 to operate, and a rewritable memory (RAM 103) that temporarily stores data required by the MPU 101 while the program is running.

[0025] The IJP also includes an input panel 104 for inputting print contents and setting values, etc., and a display device 105 for displaying the input data and print contents, etc. The input panel 104 and display device 105 use touch input display panels with transparent touch switches superimposed on the surface of a liquid crystal display screen. A bus line 106 (bus) transmits data signals, address signals, control signals, etc. from the MPU 101.

[0026] The print head 200 ejects ink 109, which is pressurized and supplied by an ink supply pump 108 from an ink container 107 in the IJP main body 100, from a nozzle 201 in the form of an ink pillar 109a, and is provided with a charging electrode 203 surrounding the position where the tip of the ink pillar 109a separates to become an ink droplet 109b.

[0027] Furthermore, the device is provided with a deflection electrode 204 that generates a deflection electric field that deflects the flying, charged ink droplets 109b in accordance with the amount of charge and directs them toward the printing target 4 for printing. It also has a gutter 205 that captures ink droplets 109b that are not used for printing, and a phase detection sensor (hereinafter referred to as an auto-phase sensor) 206 that generates a phase detection signal in accordance with the amount of charge on the ink droplets 109b captured by the gutter 205.

[0028] The IJP main body 100 is further equipped with a pump drive circuit 111 that controls the ink supply pump 108 and an ink recovery pump 110 that recovers the ink droplets 109b captured by the gutter 205 into the ink container 107. It is also equipped with an excitation voltage generation circuit 112 that excites an electrostrictive element 202 built into the print nozzle 201 to provide regularity to the timing at which the ink pillar 109a ejected from the print nozzle 201 separates into ink droplets 109b. The electrostrictive element 202 is also called a "piezoelectric element."

[0029] Furthermore, there is provided a D / A converter 115 that converts the digital signal-form charging signals output from the printing charging signal generating circuit 113 and the phase search charging signal generating circuit 114 into analog voltage signals, and an amplifier circuit 116 that amplifies the analog signal-form voltage signals output from the D / A converter 115 to generate a charging voltage to be applied to the charging electrode 203.

[0030] Furthermore, the circuit is provided with a deflection voltage generating circuit 117 that generates a deflection voltage to be applied to the deflection electrode 204, an amplifier circuit 118 that amplifies the phase detection signal in the form of an analog signal output from the auto phase sensor 206, a phase determination circuit 119 that receives the amplified phase detection signal and determines whether charging is normal, and an A / D converter 120 that receives the amplified phase detection signal and performs A / D conversion.

[0031] The MPU 101 in the IJP configured in this manner controls the pump drive circuit 111 via the bus line 106 to operate the ink supply pump 108 and the ink recovery pump 110, thereby sucking and pressurizing the ink 109 in the ink container 107 and supplying it to the print nozzle 201, causing a columnar ink pillar 109a to be ejected from the print nozzle 201, and sucking up the ink droplets 109b captured by the gutter 205 and recovering them in the ink container 107.

[0032] The tip of the ink pillar 109a ejected from the print nozzle 201 separates to become an ink droplet 109b. The timing at which the tip of the ink pillar 109a separates into an ink droplet 109b can be regulated to a predetermined phase relative to the excitation voltage by generating an excitation voltage (excitation signal) using the excitation voltage generating circuit 112 and applying the excitation signal to the electrostrictive element 202, which excites the electrostrictive element 202 of the print nozzle 201 and vibrates the ink pillar 109a.

[0033] The amount of charge on ink droplet 109b is proportional to the amount of charge on ink pillar 109a due to the potential of charging electrode 203 when ink droplet 109b separates from the tip of ink pillar 109a. Printing charging signal generating circuit 113 generates a printing charging signal for applying a charging voltage to charging electrode 203 so that the amount of charge is sufficient to deflect ink droplet 109b to a predetermined position when the tip of ink pillar 109a separates into ink droplet 109b.

[0034] In response to the charging voltage generated based on the printing charging signal, the charged ink droplets 109b are electrostatically deflected while flying between the deflection electrodes 204, and land at predetermined positions on the printing target 4. The uncharged ink droplets 109b travel in a straight line and are captured and collected by the gutter 205.

[0035] The timing for generating the printing charging signal must be such that a charging voltage can be applied to the charging electrode 203 so that when the ink pillar 109a separates into ink droplets 109b, the amount of charge is sufficient to deflect the ink droplets 109b to a predetermined position.

[0036] As shown in Figure 2, when a print object arrival sensor (for example, the first print object detection sensor 6a) detects that a print object 4 being transported by a conveyor 300 on the production line is approaching and moving in front of the print head 200, the IJP generates a printing charging voltage that charges the ink droplets 109b, and deflects and controls the ink droplets 109b to print.

[0037] During the non-printing period between the print targets 4, a phase search charging voltage as shown in FIG. 3 is generated to perform phase search. FIG. 3 illustrates the generation of the phase search charging signal. The timing of the ink column 109a's break point may change due to changes in pressure, temperature, ink material, and other factors, which may result in changes in the ink droplet shape. The inkjet recording apparatus 1 must apply a charging signal to the charging electrode at the correct timing (phase) for the current ink droplet. To perform this phase search, the phase search charging signal generating circuit 114 generates a charging signal for generating multiple phase search charging voltages with different phases relative to the excitation voltage. The phase search charging voltages are sized to deflect the charged ink droplet 109b to a degree that prevents it from jumping over the gutter 205 (i.e., allows it to be captured by the gutter 205).

[0038] The phase detection signal output from the auto phase sensor 206 according to the charge amount of the ink droplet 109 b charged by this charging voltage is input to the phase determination circuit 119 and A / D converter 120 via the amplifier circuit 118 .

[0039] The waveform of the phase detection signal output from the amplifier circuit 118 changes as the generation phase of the phase search charging voltage changes, as shown in FIG. 4 . This phase detection voltage (phase detection signal) is input to the phase determination circuit 119. The phase determination circuit 119 compares the input phase detection voltage (phase detection signal) of each phase with a threshold level, binarizes it, and outputs the binarized signal to the MPU 101. If the phase detection signal is greater than the threshold level, it is set to "1," and if the phase detection signal is less than the threshold level, it is set to "0." The MPU 101 determines that the phase at which the binarized phase detection signal changes from "0" to "1" is the optimal phase for generating a charging voltage that charges the ink particles 109b (ink droplets 109b), and controls the printing charging signal so that the printing charging voltage is generated at that phase. The MPU 101 may determine that the phase at which the phase detection signal changes from "1" to "0" is the optimum phase for generating a charging voltage to charge the ink droplets 109b, and control the printing charging signal so that the printing charging voltage is generated at that phase. Furthermore, the MPU 101 may determine the optimum phase for generating a charging voltage to charge the ink droplets 109b using other logic based on the binarized phase detection signal. For convenience, the threshold level may also be referred to as a "threshold level voltage" or "threshold voltage."

[0040] Based on the phase detection signal waveform, the inkjet recording apparatus 1 can determine the state of the inkjet recording apparatus 1. For example, as shown in Fig. 5, when the phase detection signal waveform has all of the phase detection voltages for each phase lower than the threshold level voltage, the inkjet recording apparatus 1 can determine that the ink droplets 119b cannot be formed into an ideal shape.

[0041] As shown in FIG. 6, when the phase detection signal waveform has phase detection voltages that are significantly lower than the threshold level voltage (for example, zero), it can be determined that the ink particles 119b cannot be collected in 205.

[0042] 7 is a schematic diagram showing the operating state of the pause mode of the inkjet recording apparatus 1. The pause mode of the inkjet recording apparatus 1 may also be referred to as the "pause state of the inkjet recording apparatus 1."

[0043] The pause mode of the inkjet recording apparatus 1 is a mode in which the inkjet recording apparatus 1 stops ejecting ink.

[0044] When the user turns on the power of the inkjet recording apparatus 1, the I / O operation changes from OFF to ON, and detection signals are input from the print detection sensor and rotary encoder to the control unit 15. However, the circulation system is not yet operating, and ink ejection and ink viscosity measurement / adjustment are not performed. At this time, no excitation signal is applied, no voltage is generated on the charging electrode and deflection electrode, and no phase search using the auto phase sensor 206 is performed, so this is the mode with the lowest power consumption.

[0045] 8 is a schematic diagram showing the operating state of the printable mode of the inkjet recording apparatus 1. The printable mode of the inkjet recording apparatus 1 may also be referred to as the "printable state of the inkjet recording apparatus 1." The printable mode of the inkjet recording apparatus 1 is a mode in which the inkjet recording apparatus 1 is ejecting ink and a deflection voltage is applied.

[0046] When the user turns on the power of the inkjet recording apparatus 1, the I / O operation is turned on, and detection signals are input from the print detection sensor and rotary encoder to the control unit 15. At this time, an excitation signal is applied, voltages are applied to the charging electrode and deflection electrode, and phase search is also performed using the auto phase sensor 206. The printable mode is the mode with the highest power consumption.

[0047] 9 is a schematic diagram showing the operating state of the energy saving mode of the inkjet recording apparatus 1. The energy saving mode of the inkjet recording apparatus 1 may also be referred to as the "energy saving state of the inkjet recording apparatus 1."

[0048] Even during the production of beverages and other products, containers of the printing object 4 are not always transported, and may not be transported if the container type is changed, etc. In such a situation, maintaining the printable mode with the highest power consumption is inefficient and also places a burden on the environment.

[0049] On the other hand, if the inkjet recording apparatus 1 is put into pause mode and the excitation voltage is turned OFF in this state, the ink will continue to come out without being atomized, and will be collected by the gutter 205. However, in this state, depending on the production environment, there is a problem that foreign matter may get stuck at the outlet of the print nozzle 201, making it impossible to collect the ink, and causing contamination on the production line.

[0050] Therefore, when the inkjet recording device 1 is in the printable mode and the production operation status of the print target 4 reaches a predetermined operation status (for example, when the print target 4 is not transported for a predetermined time or more), the control unit 15 transitions to an energy-saving mode that conserves more power (consuming less electricity) than the printable mode. Here, the fact that the print target 4 is not being transported is determined based on a signal (information) received from the second print target detection sensor 6b and / or the second rotary encoder 7b. Since it is determined that the print target 4 cannot be transported based on a sensor installed on the upstream conveyor 5b, rapid and highly accurate determination is possible. This signal (information) can also be said to be a signal indicating the production operation status of the print target 4, and for convenience, it is also referred to as "production operation information."

[0051] In addition to transitioning from the printable mode to the energy saving mode based on the above-mentioned sensor and encoder signals, the inkjet recording device 1 can also transition in accordance with an instruction to operate in the energy saving mode from the server 2 or an instruction based on the user's operation of the operation display unit 14.

[0052] When the inkjet recording device 1 is in the energy-saving mode and the transport of the print medium 4 is resumed, the control unit 15 controls the inkjet recording device 1 to transition from the energy-saving mode to the printable mode. The restart of the transport of the print medium 4 is determined based on information received from the second print medium detection sensor 6b and / or the second rotary encoder 7b. The sensor installed on the upstream conveyor 5b determines that the print medium 4 cannot be transported, enabling a quick and highly accurate determination. In addition to transitioning from the energy-saving mode to the printable mode based on the sensor and encoder signals, the inkjet recording device 1 can also transition from the energy-saving mode to the printable mode in response to an instruction for energy-saving mode operation from the server 2 or an instruction based on a user's operation on the operation display unit 14.

[0053] In the energy saving mode, the deflection voltage is turned off, and the excitation voltage generating circuit 112 applies to the electrostrictive element 202 an excitation signal having a lower excitation voltage and a lower excitation frequency than the high excitation voltage and high excitation frequency in the printable mode, resulting in lower power consumption than in the printable mode.

[0054] 10 is a control flowchart for automatically setting the frequency of the excitation signal and the excitation voltage to the minimum required value in the energy saving mode. When the energy saving mode is entered, the control unit 15 starts processing from step 1000, and after sequentially executing the processing of steps 1001 to 1011 described below, proceeds to step 1095 and ends the processing.

[0055] Step 1001: In the energy saving mode, the control unit 15 first obtains the current excitation voltage V.

[0056] Step 1002: The control unit 15 sets the next excitation voltage V to a value obtained by subtracting a predetermined voltage value V1 from the current excitation voltage V (=V-V1).

[0057] Step 1003: The control unit 15 applies a charging voltage to the ink particles generated by the excitation voltage V set in step 1002, and the auto phase sensor 206 detects the amount of charge.

[0058] Step 1004: The control unit 15 determines whether the voltage detected by the auto phase sensor 206 is higher than the threshold level. If the voltage detected by the auto phase sensor 206 is higher than the threshold level, the control unit 15 determines "YES" and returns to step 1001, where it again executes the process of reducing the excitation voltage and detects the amount of charge (steps 1001 to 1004).

[0059] If the voltage detected by the auto phase sensor 206 is equal to or lower than the threshold level, the control unit 15 determines “NO” and proceeds to step 1005 .

[0060] Step 1005: The control unit 15 returns the excitation voltage to the value before reduction. That is, the control unit 15 sets the next excitation voltage V to a value obtained by adding a predetermined voltage value V1 to the current excitation voltage V.

[0061] Step 1006: The control unit 15 acquires the frequency F of the current excitation signal (excitation frequency F).

[0062] Step 1007: The control unit 15 sets the value obtained by subtracting a predetermined value F1 from the current excitation frequency F as the next excitation frequency.

[0063] Step 1008: The control unit 15 applies a charging voltage to the ink particles generated at the excitation frequency F set in step 1007, and the auto phase sensor 206 detects the amount of charge.

[0064] Step 1009: The control unit 15 determines whether the voltage detected by the auto phase sensor 206 is higher than the threshold level.

[0065] If the voltage detected by the auto phase sensor 206 is higher than the threshold level, the control unit 15 judges "YES", returns to step 1006, executes the process of reducing the excitation frequency again, and detects the amount of charge (steps 1006 to 1009).

[0066] If the voltage detected by the auto phase sensor 206 is equal to or lower than the threshold level, the control unit 15 determines "NO" and proceeds to step 1000.

[0067] Step 1010: The control unit 15 returns the excitation frequency to the value before reduction. That is, the control unit 15 sets the next excitation frequency F to a value obtained by adding a predetermined frequency F1 to the current excitation frequency F.

[0068] Step 1011: The control unit 15 sets the next excitation voltage and the next excitation frequency set in step 1005 and step 1010 as the final excitation frequency and excitation voltage for the energy-saving mode. The final excitation frequency and excitation voltage for the energy-saving mode are lower than the excitation frequency and excitation voltage set in the printable mode. For convenience, the excitation frequency for the printable mode may also be referred to as the "first excitation frequency," and the excitation voltage for the printable mode may also be referred to as the "first excitation voltage." For convenience, the excitation frequency for the energy-saving mode may also be referred to as the "second excitation frequency," and the second excitation frequency is lower than the first excitation frequency. For convenience, the excitation voltage for the energy-saving mode may also be referred to as the "second excitation voltage," and is lower than the first excitation voltage.

[0069] By executing the above process flow, the control unit 15 can set the excitation frequency and excitation voltage to the minimum necessary when operating in the energy saving mode. <Effects> As described above, the inkjet recording system according to the embodiment of the present invention can reduce power consumption. As a result, the inkjet recording system according to the embodiment achieves energy saving, thereby reducing CO ２ This can contribute to reducing emissions and saving power. Furthermore, with the inkjet recording apparatus system according to the embodiment of the present invention, the ink droplet collection status can be monitored even when operating in energy saving mode, and if for some reason ink droplets cannot be collected in the gutter, ink ejection can be immediately stopped, making it possible to prevent the spread of contamination on the customer's production line. <<Modifications>> The present invention is not limited to the above embodiment, and various modifications can be adopted within the scope of the present invention. For example, in the above embodiment, the inkjet recording apparatus 1 may be connected to an external communication device and configured to be able to communicate with the server 2 via a network using the external communication device.

[0070] In the above embodiment, the server 2 may give instructions to the control unit 15, and the control unit 15 may be configured to operate the inkjet recording device 1 in accordance with the instructions from the server 2 by switching between a printable mode in which an excitation signal of a high excitation voltage (first excitation voltage) and a high excitation frequency (first excitation frequency) is applied to the electrostrictive element 202, and an energy-saving mode in which an excitation signal of a low excitation voltage (second excitation voltage) and a low excitation frequency (second excitation frequency) is applied to the electrostrictive element 202.

[0071] In the above embodiment, production operation information indicating the production operation status of the printing object 4 transported by the transport device is input to the server 2, and the server 2 may be configured to switch from the printable mode to the energy-saving mode in accordance with the production operation status indicated by the production operation information by instructing the control unit 15 when the inkjet recording device 1 is in the printable mode.

[0072] In this case, when the inkjet recording device 1 is in the printable mode, the server 2 may instruct the control unit 15 to switch from the printable mode to the energy saving mode if the production operation status indicated by the production operation information indicates that the printing object is not being transported for a predetermined period of time or more.

[0073] In this case, the server 2 may be configured to instruct the control unit 15 to switch from the energy saving mode to the printable mode when the inkjet recording device 1 is in the energy saving mode and the production operation status indicated by the production operation information indicates that the transportation of the printing object has resumed.

[0074] In this case, the server 2 may be configured to instruct the control unit 15 to switch from the printable mode to the energy saving mode when the production operation status indicated by the production operation information becomes a predetermined operation status while the inkjet recording device 1 is in the printable mode.

[0075] 1...inkjet recording apparatus, 2...server, 3...communication line, 14...operation display unit, 15...control unit, 100...IJP main body, 101...MPU, 102...ROM, 103...RAM, 104...input panel, 105...display device, 112...excitation voltage generating circuit, 113...printing charge signal generating circuit, 114...phase search charge signal generating circuit, 119...phase determination circuit, 200...print head, 202...electrostrictive element, 205...gutter, 206...phase detection sensor, 300...conveyor

Claims

1. An inkjet recording device comprising: a print head which receives a supply of ink and performs printing; and a main body which includes a control device and supplies the ink to the print head, wherein the print head has: a piezoelectric element which converts the ink into ink particles; a charging electrode which charges the ink particles; a deflection electrode which deflects the charged ink particles; and an autophase sensor which induces a voltage according to the amount of charge of the ink particles, wherein the control device is configured to be capable of switching between a printable mode in which a first excitation voltage and an excitation signal of a first excitation frequency are applied to the piezoelectric element, and an energy-saving mode in which a second excitation voltage lower than the first excitation voltage and an excitation signal of a second excitation frequency lower than the first excitation frequency are applied to the piezoelectric element.

2. An inkjet recording device as described in claim 1, wherein production operation information indicating the production operation status of the printing objects transported by a transport device is input to the control device, and the control device is configured to be able to switch between the printable mode and the energy saving mode based on the production operation information.

3. An inkjet recording device as described in claim 2, wherein the control device is configured to switch from the printable mode to the energy saving mode when the production operation status indicated by the production operation information becomes a specified operation status while in the printable mode.

4. An inkjet recording device as described in claim 2, wherein the control device is configured to switch from the printable mode to the energy saving mode when, in the printable mode, the production operation status indicated by the production operation information indicates that the object to be printed is not being transported for a predetermined period of time or more.

5. An inkjet recording device as described in claim 4, wherein the control device is configured to switch from the energy saving mode to the printable mode when, in the energy saving mode, the production operation status indicated by the production operation information indicates that transportation of the object to be printed has resumed.

6. An inkjet recording device as described in claim 1, wherein the control device is configured to, when in the energy saving mode, control the second excitation voltage and the second excitation frequency applied to the piezoelectric element to a necessary minimum based on the voltage value measured by the auto phase sensor.

7. In the inkjet recording device according to claim 6, the control device: acquires a current excitation voltage, subtracts a predetermined voltage from the acquired excitation voltage, sets the result as a new excitation voltage, and determines whether or not the voltage value of the autophase sensor is higher than a threshold voltage; if the voltage value of the autophase sensor is higher than the threshold voltage, acquires a new current excitation voltage, and sets the result as a new excitation voltage, obtained by subtracting a predetermined voltage from the acquired new current excitation voltage, repeating this process until the voltage value of the autophase sensor becomes equal to or lower than the threshold voltage; if the voltage value of the autophase sensor becomes equal to or lower than the threshold voltage, acquires a new current excitation voltage, and sets the result as a final excitation voltage by adding a predetermined voltage to the acquired new current excitation voltage; an inkjet recording device configured to control the second excitation voltage and the second excitation frequency to be applied to the piezoelectric element to a necessary minimum by determining whether a voltage value of the autophase sensor is higher than a threshold voltage, and if the voltage value of the autophase sensor is higher than the threshold voltage, a new current excitation frequency is acquired, and a value obtained by subtracting a predetermined frequency from the acquired new current excitation frequency is set as a new excitation frequency, and this process is repeated until the voltage value of the autophase sensor becomes equal to or lower than the threshold voltage; and if the voltage value of the autophase sensor becomes equal to or lower than the threshold voltage, a new current excitation frequency is acquired, and a value obtained by adding a predetermined frequency to the acquired new current excitation frequency is set as a final excitation frequency, thereby controlling the second excitation voltage and the second excitation frequency to be applied to the piezoelectric element to a necessary minimum.

8. An inkjet recording device according to claim 1, wherein the control device is configured to receive a command from an external device and switch between the printable mode and the energy saving mode based on the command.

9. An inkjet recording device system comprising: an inkjet recording device; and a server communicatively connected to the inkjet recording device via a network, wherein the inkjet recording device comprises: a print head which receives a supply of ink and performs printing; and a main body including a control device and which supplies the ink to the print head, wherein the print head has: a piezoelectric element for converting the ink into ink particles, a charging electrode for charging the ink particles, a deflection electrode for deflecting the charged ink particles, and an autophase sensor in which a voltage according to the amount of charge of the ink particles is induced, and wherein the control device is configured to be capable of switching between a printable mode in which a first excitation voltage and an excitation signal of a first excitation frequency are applied to the piezoelectric element, and an energy-saving mode in which a second excitation voltage lower than the first excitation voltage and an excitation signal of a second excitation frequency lower than the first excitation frequency are applied to the piezoelectric element.

10. An inkjet recording device system as described in claim 9, wherein production operation information indicating the production operation status of the printing object transported by the transport device is input to the control device, and the control device is configured to be able to switch between the printable mode and the energy saving mode based on the production operation information.

11. An inkjet recording device system as described in claim 9, wherein the control device is configured to receive instructions from the server and switch between the printable mode and the energy saving mode based on the instructions.

12. An inkjet recording device system as described in claim 11, wherein production operation information indicating the production operation status of the printing objects transported by a transport device is input to the server, and the server is configured to instruct the control device to alternate between the printable mode and the energy saving mode based on the production operation information.

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