JP2024009725A - Ink jet printer, control method of ink jet printer, and printing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet printer which can achieve high printing quality and high robust properties regardless of an individual difference of a nozzle, a control method of the ink jet printer, and a printing system.

SOLUTION: An ink jet printer comprises: a printing head for performing printing by ink particles; a main body for supplying ink to the nozzle; and a control part for controlling the printing head and the main body. The control part stores L-V characteristics of a reference nozzle and an excitation voltage condition in which printing is possible, measures the L-V characteristics which indicate a relationship between a cut position of an ink column discharged from the nozzle and the excitation voltage, and calculates the excitation voltage condition of a mounted nozzle on the basis of the L-V characteristics of the reference nozzle and the excitation voltage condition in which printing is possible, and the L-V characteristics of the mounted nozzle. Then, the control part executes printing by applying the calculated excitation voltage condition.

SELECTED DRAWING: Figure 2

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to an inkjet printer, an inkjet printer control method, and a printing system.

Among inkjet printers, charge-controlled inkjet printers are mainly used as industrial printers, such as for printing serial numbers, expiration dates, etc. on products moving on a production line. In this charge-controlled inkjet printer, liquid ink filled in an ink tank is pressurized by a pump and supplied to nozzles of a print head. The nozzle continuously ejects the supplied ink as an ink column, but during ejection, an excitation voltage is applied to a piezoelectric element installed adjacent to the nozzle to excite it, causing periodic vibrations to the ink. Given. The ink column subjected to vibration is cut midway to form ink particles that are generated continuously (periodically) and fly at high speed. By arranging a charging electrode at or near the position where the ink droplets are formed (the ink cutting position) and generating an electric field in the charging electrode, each ink droplet flying at high speed can be charged. By applying an electric field corresponding to the print content to the charging electrode, each ink droplet is given the necessary amount of charge according to the print content. A deflection electrode consisting of two electrodes to which a constant voltage is applied is arranged downstream of the charging electrode, and each charged ink particle is applied as it flies within the deflection electrode. The direction of flight is deflected depending on the amount of charge. Then, the deflected ink particles are caused to land (adhere) on a moving object to be printed by a conveyance device, and the ink particles are used to print on the object to be printed. Note that ink particles that are not charged within the charging electrode travel straight through the deflection electrode, are captured by the gutter, and are collected in the ink container as recovered ink.

In such inkjet printers, the position where the ink column ejected from the nozzle is cut and becomes an ink droplet (the distance from the tip of the nozzle to the position where the ink droplet becomes), that is, the "cutting position", must be maintained at an appropriate position. The charging electrode cannot charge the ink particles in flight with an appropriate charge, making it impossible to achieve high-quality printing. Therefore, it is important to appropriately control the cutting position so that it falls within a predetermined range. It is known that the cutting position can be adjusted by applying an excitation voltage to a piezoelectric element installed adjacent to the nozzle, and when printing, an excitation voltage that enables printing is applied to the nozzle (more Specifically, the excitation voltage is applied to a piezoelectric element installed adjacent to the nozzle.

Incidentally, printing environments and printing objects are diverse, and there are multiple types of ink that can be used in inkjet printers. In addition to the type of ink, the appropriate (printable) print settings (excitation voltage, excitation frequency, pump pressure, charging voltage, deflection voltage values, etc.) depend on various conditions such as the nozzle and temperature environment. different. As mentioned above, it is difficult to achieve highly accurate printing if the excitation voltage conditions applied to the nozzle are not appropriate for the type and temperature of the ink, so when printing, it is necessary to set the excitation voltage conditions appropriately. It is required to print after that. To address these issues, a technique aimed at appropriately setting excitation voltage conditions (excitation voltage value and excitation frequency) is disclosed, for example, in Japanese Patent Publication No. 2011-502827 (Patent Document 1). .

Patent Document 1 takes into account the movement of the dividing point (dividing position) in the ink column, and guarantees that the characteristic indicating the modulation voltage versus the dividing position has a predetermined slope or a slope related to this predetermined slope. A technique has been disclosed in which an excitation voltage condition is determined such that the excitation voltage condition is determined, and printing is performed using an excitation voltage that guarantees the determined excitation voltage condition.

Special Publication No. 2011-502827

If the technology of Patent Document 1 described above is used, the excitation voltage conditions that allow printing are determined for a certain nozzle in response to changes in ink type and temperature, etc., and the determined excitation voltage is applied to the nozzle (built-in piezoelectric element). ) can be applied.

However, even if the excitation voltage conditions (excitation voltage value and excitation frequency) are appropriate for a certain nozzle, the excitation voltage conditions are not necessarily appropriate when printing using another nozzle. In Patent Document 1, the excitation voltage condition is set to one value, but insufficient consideration is given to the fact that the appropriate excitation voltage condition will change if the type of ink is different even for the same nozzle, and the robustness is There remains a technical issue of lack of.

Further, Patent Document 1 does not take into consideration that there may be large differences in appropriate (printable) excitation voltage conditions based on individual differences between nozzles used for printing. That is, even if the inkjet printer, the type of ink used for printing, the temperature environment, and other conditions are the same, the excitation voltage conditions that allow printing will differ depending on the nozzle attached to the print head of the inkjet printer. This is because there are individual differences between nozzles even if they are within the same standard. The difference in excitation voltage conditions that allow printing due to individual differences between nozzles is so large that it cannot be ignored, and even if a certain nozzle satisfies an appropriate excitation voltage condition, it is so large that other nozzles deviate from the excitation voltage conditions that allow printing. Therefore, if individual differences between nozzles are not taken into account, there is a risk that print quality will be significantly reduced, and robustness will be lacking. Furthermore, if there is a large difference in the excitation voltage conditions that allow printing for each nozzle, it is necessary to manually check and set the excitation voltage conditions that allow printing for each nozzle, which takes a lot of effort.

An object of the present invention is to provide a highly robust inkjet printer, an inkjet printer control method, and a printing system that achieve high printing quality regardless of individual differences in nozzles.

In order to achieve the above-mentioned object, the present invention provides, for example, a nozzle that continuously generates ink particles, a charging electrode that charges the ink particles with an electric charge corresponding to the printed content, and a device that uses the ink after being charged. a print head having a deflection electrode that deflects particles and a gutter that captures the ink particles that are not used for printing; a main body that supplies ink to the nozzle and collects ink captured by the gutter; An inkjet printer comprising: a control unit for controlling an inkjet printer, the control unit storing an LV characteristic representing a relationship between an ink cutting position in a reference nozzle and an excitation voltage and an excitation voltage condition capable of printing; The LV characteristic of the nozzle is measured, and the nozzle is determined based on the relative positional relationship between the LV characteristic of the reference nozzle and the LV characteristic of the nozzle and the excitation voltage condition of the reference nozzle. The inkjet printer calculates the excitation voltage conditions that allow printing, and controls the print head based on the calculated excitation voltage conditions of the nozzles.

Other examples of the present invention include a nozzle that continuously generates ink particles, a charging electrode that charges the ink particles with a charge corresponding to the printed content, a deflection electrode that deflects the charged ink particles, and a print head having a gutter that captures the ink particles not used for printing, a main body that supplies ink to the nozzle and collects the ink particles captured by the gutter, and a control unit that controls the print head and the main body. A control method for an inkjet printer comprising: storing an LV characteristic representing a relationship between an ink cutting position and an excitation voltage in a reference nozzle and an excitation voltage condition capable of printing; The LV characteristic representing the relationship between the cutting position of the ink and the excitation voltage is measured, and the relative positional relationship between the LV characteristic of the reference nozzle and the LV characteristic of the nozzle and the LV characteristic of the reference nozzle are measured. The present invention is a control method for an inkjet printer, in which the excitation voltage condition that allows printing in the nozzle is calculated based on the excitation voltage condition, and printing is performed based on the calculated excitation voltage condition in the nozzle.

Further, other examples of the present invention include a nozzle that continuously ejects ink particles, a charging electrode that charges the ink particles with an electric charge corresponding to the printed content, and a charging electrode that charges the ink particles with an electric charge corresponding to the amount of the charged ink particles. An inkjet printer comprising: a print head having a deflection electrode for deflecting and a gutter for capturing the ink particles not used for printing; a main body for supplying ink to the nozzles; and a control unit for controlling the print head and the main body. , the LV characteristic indicating the relationship between the ink cutting position and the excitation voltage of the reference nozzle, and the excitation voltage conditions for printing are memorized, the LV characteristic of the ink ejected from the nozzle is measured, and the LV characteristic of the ink ejected from the nozzle is measured; an arithmetic device that calculates a printable excitation voltage condition of the nozzle based on the relative positional relationship between the LV characteristic of a reference nozzle and the LV characteristic of the nozzle and the excitation voltage condition of the reference nozzle; The control unit is a printing system that controls the print head by inputting the calculated excitation voltage at the nozzle that allows printing.

According to the present invention, it is possible to realize a highly robust inkjet printer, an inkjet printer control method, and a printing system that achieve high printing quality regardless of individual differences in nozzles.

1 is a diagram showing the appearance of an inkjet printer in Example 1 of the present invention. 1 is a diagram showing the internal configuration of an inkjet printer in Example 1. FIG. It is an LV diagram (a diagram showing the relationship between the cutting position L of the ink column and the excitation voltage V) created from the camera-captured image. It is an LV diagram created using the optimum phase. FIG. 3 is a comparison diagram between an LV diagram created from a camera-captured image and an LV diagram created using the optimum phase. FIG. 6 is a diagram for explaining calculation of the printable excitation voltage range in the nozzle (second nozzle) to be calculated. FIG. 7 is a diagram for explaining the estimation calculation of the printable excitation voltage range in the nozzle (second nozzle) to be calculated. These are examples of printing patterns when it is determined that "printing is possible" and "printing is not possible" in printing evaluation. 3 is an LV diagram of a reference nozzle (first nozzle) in Example 1. FIG. 3 is an LV diagram of the second nozzle in Example 1. FIG. FIG. 7 is a diagram showing a comparison between an actually measured value and an estimated calculated value of the printable excitation voltage range of the second nozzle. It is a figure for explaining the composition in Example 2 of the present invention. It is a figure which shows the printing system configuration in Example 5 of this invention.

Hereinafter, the present invention will be explained in detail using specific examples. It should be noted that the present invention is not to be construed as being limited to the embodiments described below, and those skilled in the art will easily be able to change the configuration without departing from the technical idea or gist of the present invention. be understood. Furthermore, in the configurations of the embodiments described below, the same equipment and parts having similar operations and functions are denoted by the same reference numerals, and overlapping explanations may be omitted. In addition, the position, size, shape, range, etc. of each component shown in the drawings are simplified to facilitate understanding of the present invention, and the actual position, size, shape, range, etc. of each component are shown in a simplified manner. It does not represent.

[Example 1]
Next, an inkjet printer according to a first embodiment of the present invention will be described in detail using FIGS. 1 to 10. FIG. 1 is a diagram showing the external appearance of an inkjet printer in Example 1, and FIG. 2 is a diagram showing the internal configuration of the inkjet printer in Example 1 as a block diagram. 3 to 10 are diagrams used to explain the first embodiment.

(Overall configuration of inkjet printer)
First, the overall configuration of an inkjet printer will be outlined with reference to FIG. 1. In FIG. 1 , an inkjet printer 100 includes a main body 1 and a print head 2 . A cable 4 connects the main body 1 and the print head 2. Inside the main body 1, there are an ink tank that stores ink for printing, a circulation pump that pumps out the ink in the ink container and supplies it to the print head 2, a pressure reducing valve that adjusts the ink to a predetermined pressure, piping that connects them, etc. is provided. Ink output from the main body 1 after being adjusted to a predetermined pressure is supplied to the nozzles in the print head 2 through a cable 4. The print head 2 is supplied with ink, generates ink particles internally, applies a necessary charge to the ink particles, and deflects the ink particles to perform printing (dot printing) on an object to be printed using the ink particles. Furthermore, a display section 5 and a reading section 7 are provided on the front side of the main body 1. The display unit 5 displays information and the like regarding operations to be performed by the user. The display unit 5 has an input function using a touch panel on the upper surface of the screen, and allows information (data) to be input by a user's operation. The reading unit 7 is provided to read information recorded on an information recording medium attached to an ink cartridge or the like. The information recording medium is, for example, an IC tag, a barcode, or a two-dimensional code (for example, a QR code (registered trademark)). When the user performs operations such as input via the display section 5, the user may also perform an operation of bringing the IC tag of the ink cartridge close to the reading section 7 at the same time. It is set up. Further, an internal control section 200 (not shown in FIG. 1) is provided in the main body 1, and the information inputted from the display section 5 and the reading section 7 is transmitted to the main body 1. The control unit 200 controls pumps, valves, etc. in the main body 1, and controls nozzles, charging electrodes, etc. provided in the print head. Note that control signals (drive signals) and the like from the control section 200 are given to the print head 2 via a line provided in the cable 4.

(Internal configuration of inkjet printer)
Next, the specific configuration of the inkjet printer in Example 1 will be described using FIG. 2. In FIG. 2, an inkjet printer 100 includes a main body 1, a print head 2, and a control section 200. Further, a printed object detector 3 is installed outside the inkjet printer 100. The printed object detector 3 detects a printed object 261 (product, etc.) moving on the conveyance device 260 and outputs the detected object to the control section 200 . The control unit 200 can optimally adjust the timing of printing start by using this detection signal.

(Main body configuration)
In FIG. 2, main body 1 is the part of inkjet printer 100 excluding print head 2. In FIG. That is, the main body 1 in this embodiment includes an ink supply section, an ink recovery section, and a control section 200. Note that the control unit 200 may be provided outside the main body 1. The ink supply section is a device for supplying ink to the print head 2 (more directly, to the nozzles 211). The "ink supply section" in this embodiment includes an ink tank 240 containing ink 241, a circulation pump 245, a pressure reducing valve 246, a filter 250, an auxiliary ink tank 251, an intensification liquid tank 252, and a pipe 232a. . Further, the "ink recovery section" is for recovering ink (ink particles) captured by the gutter 215 into the ink tank 240, and in this embodiment is constituted by a recovery pump 233 and piping 232b.

The ink tank 240 is connected to the nozzle 211 by a pipe 232a. On the other hand, the gutter 215 is connected to the ink tank 240 through a pipe 232b. Pipes 232a and 232b constitute an ink flow path. A circulation pump 245 and a pressure reducing valve 246 are installed in the middle of the pipe 232a. A filter 250 is installed between the circulation pump 245 and the pressure reducing valve 246. Note that the arrangement of the filter 250 is not limited to the above position. Since the filter is mainly intended to prevent clogging of the pipe 232a and the nozzle 211, it can be installed at any position on the pipe 232a as long as this purpose can be achieved. Ink 241 in the ink tank 240 is sucked up by a circulation pump 245 and supplied to the nozzle 211 with its pressure adjusted by a pressure reducing valve 246.

Furthermore, in this embodiment, an auxiliary ink tank 251 and an intensification liquid tank 252 are connected to the ink tank 240, so that the respective liquids can be replenished. Here, the auxiliary ink tank 251 replenishes ink when the ink in the ink tank is consumed. The intensification liquid tank 252 is used to supply intensification liquid to the ink tank 240 and appropriately adjust the viscosity of the ink 241. The intensifying liquid is a liquid that replenishes highly volatile components (solvent) contained in the ink.

(Print head configuration)
Next, the configuration of the print head 2 shown in FIG. 2 will be explained in detail. The print head 2 includes a nozzle 211 that receives ink supplied under pressure through a pipe 232a and discharges an ink column 221. This nozzle 211 is provided with a piezoelectric element 212 (vibrator) for applying vibration to the ejected ink column. By applying an excitation voltage from the control unit 200 to the piezoelectric element 212, the ink column 221 is vibrated, the ink column is cut in the middle, and ink particles 222 are generated. By exciting the ink column 221, ink particles are continuously generated and fly at high speed.

The print head 2 also includes a charging electrode 213 that forms an electric field to charge the ink particles 222 generated by the nozzle 211, and a deflection electrode 214 that changes the trajectory of the charged ink particles 222 according to the amount of charge. , and a gutter 215 that collects ink particles that did not contribute to printing. The charging electrode 213 applies an electric charge corresponding to the shape of the character to be printed to the ink particles in flight, thereby charging the ink particles. The charged ink particles fly within the deflection electrode 214. A constant voltage is applied to the deflection electrode 214, and the flight direction of each charged ink droplet is deflected according to the amount of charge applied when flying within the deflection electrode.

The ink particles 222 deflected by the deflection electrode 214 fly toward the printing object 261 that is being conveyed by the conveying device 260, and land (adhere) on the printing object 261, thereby causing a droplet to be applied to the printing object 261. Perform printing. The movement of the transport device 260 is monitored by a rotary encoder 262. Rotary encoder 262 generates a pulse signal depending on the moving speed of conveyance device 260. The moving speed detected by the rotary encoder 262 is input to the control unit 200 of the inkjet printer 100, and is used by the control unit 200 to adjust the timing of printing.

In this way, while the inkjet printer 100 is in operation, it is operated so that the ink particles 222 are continuously ejected even when the printing object 261 has arrived at the printing position and printing is not being performed. Therefore, the charge control type inkjet printer 100 is also called a continuous type inkjet printer or a continuous type inkjet printer.

(Configuration of control unit)
Next, the control section 200 that controls the print head 2 and the main body 1 will be explained. The control unit 200 controls the excitation voltage (excitation voltage value and excitation frequency) applied to the nozzle 211 (more specifically, the piezoelectric element 212), the charging voltage applied to the charging electrode, and the deflection electrode according to the set software parameters. The deflection voltage applied, the pressure of ink supplied to the nozzle, etc. are controlled. Note that detailed explanations regarding the control of the ink supply section and the ink recovery section of the main body 1, which are not directly related to the description of the present invention, will be omitted below.

First, the control unit 200 in this embodiment includes an MPU 201 (microprocessing unit) that executes arithmetic processing to control the main body 1 and the print head 2, and stores control programs and data necessary for the MPU 201 to operate. The program includes a ROM 202 (read-only memory) for storing data, and a RAM 203 (random access memory) for temporarily storing data required during program execution. The ROM 202 records ink information about the ink 241 and software parameter values optimal for control. The ink information includes, for example, information regarding the ink type name or solvent of the ink 241. In the software used for printing control of the ink 241 and operation control of the inkjet printer, various parameter values are set for printing control.

Further, the control section 200 includes an input panel 204 for inputting printing contents, setting values, etc., and a display control section 205. The input panel 204 corresponds to the touch panel of the display unit 5. The display control section 205 controls the contents displayed on the display section 5, such as input data and printed contents.

Note that the control unit 200 is provided with a bus line 206. The MPU 201, ROM 202, RAM 203, input panel 204, and display control unit 205 are connected via a bus line 206, and can transmit and receive signals between each device. Further, other devices in the control unit 200 described below are similarly connected to the bus line 206, and each device is configured to be able to transmit and receive data to and from each other. The bus line 206 also has the function of transmitting data signals, address signals, and control signals of the MPU 201.

Furthermore, the control unit 200 can be connected to a storage device 209 (storage unit) that stores programs, print data, and the like. The control unit 200 stores information (
data) is stored in the internal RAM 203. A typical example of the storage device 209 is a USB memory. The control unit 200 controls excitation voltage (excitation voltage value and excitation frequency), pump pressure, charging voltage, deflection voltage, etc. according to set software parameters.

Further, the control section 200 includes a charging voltage generation circuit 207 and an excitation voltage generation circuit 208. The charging voltage generation circuit 207 applies a voltage to the charging electrode 213 such that the amount of charge applied to the ink droplets 222 corresponds to the character signal. The excitation voltage generation circuit 208 generates a high frequency excitation voltage to be applied to the piezoelectric element 212 provided in the nozzle 211. As this excitation voltage, as will be described later, an excitation voltage that guarantees the printable excitation voltage conditions calculated by the excitation voltage calculation section 274 is selected.
By applying an excitation voltage to the piezoelectric element 212, the ink column 221 immediately after being ejected from the nozzle 211 can be vibrated to continuously generate ink particles. A charging voltage generation circuit 207 and an excitation voltage generation circuit 208 are also connected to the bus line 206.

Furthermore, the control unit 200 in this embodiment includes an optimum phase detection circuit 210, a characteristic measurement unit 273 that measures characteristics indicating the relationship between the cutting position of the ink column 221 and the excitation voltage, and an optimum excitation voltage for each nozzle. An excitation voltage calculation unit 274 that calculates conditions is provided. The characteristic measurement section 273 and the excitation voltage calculation section 274 calculate excitation voltage conditions that allow printing in the mounted nozzle 211. A specific method of calculating the excitation voltage conditions that allow printing will be described later.

The optimum phase detection circuit 210 has a function of dividing one period of vibration generated by the piezoelectric element 212 into, for example, 16 phases, and automatically determining at which timing (phase) electric field application is most suitable for charging ink particles. have Specifically, a charging electrode 213 applies a weak electric field that does not affect printing to the ink particles to be ejected at each phase, and the ink particles having a weak amount of charge on the ink at each phase condition are transferred to the gutter 215. After sucking in the ink particles, a charge amount measurement unit 234 provided in the middle of the ink collection pipe 232b measures the feeble charge amount of the ink particles, and the phase when the measured charge amount is the highest is detected as the optimal phase. (judge.

Next, details of the characteristic measuring section 273 in the control section 200 will be explained. The characteristic measuring section 273 is provided to measure a characteristic indicating the relationship between the cutting position of the ink ejected from the nozzle and the excitation voltage. The characteristic indicating the relationship between the cutting position and the excitation voltage is referred to as the "LV characteristic" in this specification.

This LV characteristic is a characteristic that expresses the correspondence between the cutting position and the excitation voltage, and is easier to understand if it is expressed as a line diagram in which the correspondence is plotted on a graph. A diagram representing the LV characteristic is called an "LV diagram." In the following description, the characteristic measuring section 273 will be described as one that measures an LV diagram. In the following description, examples will be explained using an LV diagram, but the measurement method using the LV diagram is just one example. The present invention can be implemented as long as the LV characteristics can be determined.

(Measurement method of LV diagram)
Next, a specific method of measuring the LV diagram will be explained. The characteristic measurement unit 273 measures an LV diagram showing the relationship between the cutting position of the ink column 221 ejected from the nozzle 211 and the excitation voltage, and there are two possible methods for this measurement.

The first method is to directly obtain the cutting position of the ink from the image taken by the camera while changing the excitation voltage. The second method is a method that uses the optimal phase obtained by the optimal phase detection circuit 210. The characteristic measurement unit 273 may use any method to measure the LV diagram. In the embodiment shown in FIG. 2, an LV diagram is measured using an image taken by a camera. Therefore, in FIG. 2, a camera 271 is provided near the charging electrode 213 to detect the cutting position where the ink column is cut into ink particles. to measure the LV diagram. When using the second method, the LV diagram can be measured by inputting the optimal phase detected by the optimal phase detection circuit 210 to the characteristic measuring section 273, as indicated by the broken line arrow in FIG.

Next, the first method and the second measurement method will be explained in more detail.
First, the first method (a method for measuring an LV diagram using an image taken with a camera) will be explained in detail. In FIG. 2, the cutting position of the ink column 221 ejected from the nozzle 211 is determined by photographing the ink column 221 illuminated by a strobe light 272 installed near the charging electrode 213 as an image with a camera 271. The same value as the excitation frequency of the excitation voltage applied to the piezoelectric element 212 is used as the excitation frequency of the strobe illumination 272 so that the ink column 221 ejected from the nozzle 211 can be photographed as a still image. By photographing with the camera 271 while changing the excitation voltage, a group of still images of the ink column 221 under each excitation voltage condition can be obtained. This still image group is sent to the characteristic measuring section 273. The characteristic measuring unit 273 extracts the cutting position of the ink column 221 corresponding to each excitation voltage using the ejection port of the nozzle 211 as a reference point from the still image group. In this way, the characteristic measurement unit 273 can perform image processing on the still images taken by the camera 271 to obtain (measure) the LV diagram.

FIG. 3 shows an example of an LV diagram of the ink column 221 ejected from the nozzle 211, created by the characteristic measurement unit 273. The horizontal axis of the diagram in FIG. 3 is the excitation voltage, and the vertical axis indicates the cutting position of the ink when each excitation voltage is applied. As can be seen from the LV diagram shown in FIG. 3, as the excitation voltage was increased, a minimum point first appeared at the cutting position of the ink column 221, and as the excitation voltage was further increased, a maximum point was observed. Note that the maximum point may not be observed depending on the excitation voltage range and various conditions to be measured.

Next, a second measurement method (a second method of measuring the LV diagram by using the optimum phase) will be explained. Here, a case will be considered in which one period of vibration generated by the piezoelectric element 212 is divided into 16 phases and the optimum phase is detected. Assuming that the optimum phase is shifted by Δn phases between two excitation voltage conditions, the time difference Δt in the cutting timing of the ink column 221 can be expressed by the following formula using the period T of vibration generated by the piezoelectric element 212. be done.
Δt=(T/16)・Δn……(1)

Note that the interval between the excitation voltage conditions must be set sufficiently small so that the optimum phase difference Δn is within one cycle (within 16 phases). The difference ΔL in the ink cutting point between the two excitation voltage conditions is expressed by the following equation using the flow velocity v of the ink column 221.
ΔL=v・Δt=v・(T/16)・Δn……(2)

Since v and T are constant between the two excitation voltage conditions, it can be seen from equation (2) that a proportional relationship is established between the difference ΔL at the ink cutting point and the phase difference Δn between the optimal phases. Therefore, if the integrated value of the phase difference ΔL between the excitation voltage conditions is plotted against the excitation voltage, the cutting position L can be determined, and a diagram showing the same tendency as FIG. 3 can be drawn. In order to confirm this, the optimal phase under each excitation voltage condition is detected by the optimal phase detection circuit 210 while the ink column 221 is ejected from the nozzle 211 under the same conditions as in the first method, and the detected optimal phase is characterized. It was sent to the measuring section 273. An LV line in which the minimum point of the excitation voltage generated by the characteristic measurement unit 273 is set to 0 as the reference point on the vertical axis, and the integrated value of the phase difference of the optimum phase between each excitation voltage is plotted against the excitation voltage. A diagram is shown in FIG. In FIG. 4, as the excitation voltage was increased, local minimum points and maximum points were observed as in the case of FIG. 3.

Here, in order to compare the two measurement methods, a diagram is shown in which the LV diagram obtained by the first method and the LV diagram obtained by the second method are superimposed. 5. As can be seen from FIG. 5, the overall trend and the positions of the minimum and maximum points are almost the same in the two measurement methods. Although the absolute value of the distance of the ink cutting position is not known in the LV diagram obtained from the optimal phase (second method), when estimating the excitation voltage condition for each nozzle, which will be described later, the absolute value of the ink cutting position is unnecessary. Therefore, the LV diagram obtained from the phase difference integrated value of the optimal phase can also be used as an LV diagram showing the relationship between the cutting position of the ink column 221 ejected from the nozzle 211 and the excitation voltage. I understand.

(Calculation method for printable excitation voltage conditions)
Next, a description will be given of the calculation contents of the excitation voltage calculation unit 274 shown in FIG. 2, that is, the method of calculating the excitation voltage conditions that allow printing in the nozzle 211. As a printable excitation voltage condition, it is essential to determine the printable excitation voltage range (appropriate excitation voltage value range and excitation frequency range), and here we will explain how to estimate and calculate the printable excitation voltage range. explain. As already explained, the excitation voltage range that can be printed differs depending on the nozzle installed in the inkjet printer. Regarding the difference, as a result of examining the printable excitation voltage range for each nozzle as well as the LV diagram for each nozzle, we found that the difference in the printable excitation voltage range between nozzles and the LV diagram between nozzles We discovered a characteristic in which the deviation of the horizontal axis (logarithmic axis of excitation voltage V) is linked.

Therefore, in Example 1 (FIG. 2), based on this characteristic, a nozzle with a known printable excitation voltage range is used as a reference, and the printable excitation voltage of a nozzle with an unknown printable excitation voltage range is set as a reference. We considered a configuration in which the range is estimated from a relative comparison of LV diagrams. Hereinafter, the reference nozzle whose LV diagram (LV characteristics) and printable excitation voltage range are known will be referred to as the "first nozzle," and the target nozzle whose printable excitation voltage range is to be estimated will be referred to as the "second nozzle." ”. That is, in the embodiment shown in FIG. 2, the nozzle 211 attached to the print head 2 is the second nozzle.

Next, a method for determining the printable excitation voltage range of the second nozzle (nozzle 211) from the LV diagram (LV characteristics) and the data of the first nozzle whose printable excitation voltage range is known is shown in the figure. This will be explained using 6A. (a) of FIG. 6A is an LV diagram of the first nozzle, and (b) is an LV diagram of the second nozzle. Here, the LV diagram (LV characteristic) and printable excitation voltage range of the first nozzle are known. In this first embodiment, the known LV diagram (LV characteristic) of the first nozzle and the printable excitation voltage range are stored in the memory (ROM 202 or RAM 203) inside the control unit 200. In the embodiment of FIG. 2, it is assumed that the information is stored in the ROM 202. The stored LV diagram and printable excitation voltage range for the first nozzle are used during calculation processing in the excitation voltage calculation section 274. The LV diagram (LV characteristic) of the second nozzle is measured by the characteristic measuring section 273 using the above-described measuring method.

Here, as shown in FIG. 6A (a), the printable excitation voltage range when the first nozzle is installed (when the first nozzle is installed) is the area between the minimum points of the LV diagram. shall be. On the other hand, as shown in FIG. 6A (b), the LV diagram (when the second nozzle is attached) measured by the characteristic measurement unit 273 is different from the L-V diagram when the first nozzle is attached. If the excitation voltage is on the relatively low excitation voltage side compared to the V diagram, the excitation voltage range that can be printed when the second nozzle is installed is also on the relatively low excitation side as shown in the diagram. It can be assumed that this is the case. Although it is necessary to eject ink with the second nozzle attached to an inkjet printer in order to measure the LV diagram of the second nozzle, it is possible to measure the relative positional relationship (position of excitation voltage) without evaluating the printing. It is possible to calculate the printable excitation voltage range of the second nozzle using (a) and (b) (degree of positional deviation).

Further, depending on the type of ink, the excitation voltage range in which printing is possible when the first nozzle is attached may be in a region on the lower excitation side than the minimum point on the LV diagram. Such a case is shown in FIG. 6B. In FIG. 6B, (a) is an LV diagram of the first nozzle, and (b) is an LV diagram of the second nozzle. In this case as well, as shown in FIG. 6B(b), the excitation voltage range that can be printed when the second nozzle is installed is determined by comparing the relative positional relationship of the LV diagrams of the first nozzle and the second nozzle. It is possible to perform estimation calculations as shown in .

As shown in FIGS. 6A and 6B, the relative positional relationship between the LV diagram and the excitation voltage range that can be printed can change depending on the type of ink. Although it is difficult to determine the excitation voltage conditions, in the present invention, the attachment of the second nozzle is determined by comparing the relative positional relationship of the LV diagram using the first nozzle, whose printable excitation voltage range is known, as a reference. Since the printable excitation voltage range at the time is estimated, an appropriate excitation voltage range for the second nozzle can be determined.

As described above, the ROM 202 stores ink information about the ink 241 and software parameter values optimal for printing control. The printing control parameters include information regarding the LV diagram of the first nozzle, excitation voltage conditions that allow printing with the first nozzle (including the excitation voltage range that can be printed, and other information such as pump pressure, charging voltage, deflection voltage, etc.) (may include ink viscosity).

Further, the information regarding the LV characteristic of the first nozzle (reference nozzle) serving as a standard is not particularly limited as long as it is information that can be relatively compared with the LV characteristic of the second nozzle. For example, the information regarding the LV diagram of the first nozzle may be the LV diagram itself of the first nozzle, or the information regarding the LV diagram of the first nozzle may be the LV diagram of the first nozzle. Since there are minimum points and maximum points in the V diagram, the excitation voltage value at the minimum point or maximum point may be used. Among these, the excitation voltage value at the minimum point of the LV diagram is suitable as information regarding the LV diagram to be recorded in the ROM 202. This is because the entire LV diagram requires a large amount of information to be recorded in the ROM 202. Furthermore, the maximum point in the LV diagram may not appear depending on the measurement conditions, as described above.

Next, an example of a procedure for specifically determining the printable excitation voltage range of the nozzle 211 (second nozzle) in the first embodiment described above will be described.
First, a first nozzle was attached to the inkjet printer 100 filled with ink 241. Printing was evaluated under specified pressure and excitation frequency conditions, and the excitation voltage range that could be printed was experimentally determined. The printing pattern shown in FIG. 7 was used for printing evaluation. In FIG. 7, (a) shows a normal printing state, and (b) shows an abnormal printing state. If the ink particles land on the printing substrate (printed object) at a predetermined position and the characters can be drawn, it is "printable"; if the ink particles do not land on the printing substrate at the predetermined position and the characters are drawn. If it was not possible to print, it was determined visually that it was not possible to print. Further, the LV diagram was measured by the characteristic measuring section 273 using the optimum phase. The measured LV diagram of the first nozzle is shown in FIG. In the case of FIG. 8, the excitation voltage value Vm1 at the minimum point of the LV diagram of the first nozzle was 141V. The printable excitation voltage range of the first nozzle was 102 to 198V. Based on the above experimental results, the ROM 202 stores the name of the ink 241, the printable excitation voltage range when the first nozzle is attached, the pressure of the ink supplied at that time, the excitation frequency, the ink viscosity, and the first nozzle. The excitation voltage value Vm1 at the minimum point of the LV diagram when the nozzle was attached was recorded.

Next, the nozzle 211 (second nozzle) used for actual printing was attached to the inkjet printer 100 filled with the ink 241. The pressure, excitation frequency, and ink viscosity information at the time when the printing evaluation was performed with the first nozzle are called from the ROM 202, and the inkjet printer 100 is set to have the same conditions as when the printing evaluation was performed with the first nozzle. The LV diagram was measured via the characteristic measuring section 273 using the optimum phase. The measured LV diagram of the second nozzle is shown in FIG. The excitation voltage value Vm2 at the minimum point of the LV diagram of the second nozzle was 180V.

The excitation voltage calculation unit 274 stores an excitation voltage value Vm2 at the minimum point of the LV diagram when the second nozzle is installed, and an excitation voltage value Vm1 at the minimum point of the LV diagram when the first nozzle is installed from the ROM 202. Then, the printable excitation voltage range when the first nozzle was installed was called. In order to quantify the relative positional relationship between the first nozzle and the second nozzle in the LV diagram, the excitation voltage calculation unit 274 determined the relative ratio C between Vm2 and Vm1 from "C=Vm2/Vm1".

The relative ratio of the first nozzle and the second nozzle in this example was C=180/141=1.28. Since the deviation of the horizontal axis (logarithmic axis of excitation voltage V) of the LV diagram between the nozzles and the deviation of the excitation voltage range that can be printed between the nozzles are linked, this relative ratio C is used to determine whether the second nozzle Calculate the excitation voltage range that can be printed. In other words, the printable excitation voltage range of the first nozzle was actually measured to be 102 to 198V, so from 102 x 1.28 = 130V and 198 x 1.28 = 253V, the printable excitation voltage range of the second nozzle is The estimated value was calculated to be 130 to 253V. The estimated value of the printable excitation voltage range of the second nozzle (nozzle 211) was used as the print setting condition of the inkjet printer 100 equipped with the second nozzle.

In order to confirm the validity of this estimated calculation, we performed a printing evaluation using the inkjet printer 100 equipped with the second nozzle and measured the excitation voltage range that can be printed, which was 126 to 258 V, which is very close to the estimated value. It turned out to be a value. FIG. 10 shows actual measured values and estimated values of the printable excitation voltage range of the first nozzle and the second nozzle.

As explained above, according to the first embodiment of the present invention, the printable excitation voltage range, which differs for each nozzle, is estimated from the LV diagram for each nozzle, and applied to the print setting conditions of the inkjet printer. Accordingly, it is possible to provide a highly robust inkjet printer that achieves high print quality regardless of individual differences in nozzles.

In addition, although the above-mentioned Example 1 (FIG. 2) showed an example in which the characteristic measurement section 273 and the excitation voltage calculation section 274 were provided in the control section 200, the present invention does not need to be limited to such a configuration. . That is, in the first embodiment described above, the characteristic measurement section 273 and the excitation voltage calculation section 274 were provided in the control section 200 in order to facilitate understanding, but instead, the characteristic measurement section 273 and the excitation voltage calculation section 274 were provided in the MPU 201 of the control section 200. 273 and the excitation voltage calculation section 274 may be provided. In that case, the characteristic measurement section 273 and the excitation voltage calculation section 274 become unnecessary, and the configuration of the control section 200 can be simplified.

Further, in the first embodiment described above, an example was shown in which information regarding the LV diagram of the second nozzle was measured within the control unit 200, but for example, the L-V diagram of the second nozzle calculated by the characteristic measuring unit 273 The information regarding the V-diagram may be obtained by a calculation device provided outside the inkjet printer 100 that uses the second nozzle (for example, an inkjet printer other than the inkjet printer 100 shown in FIG. 2). good. In that case, information regarding the LV diagram of the second nozzle obtained from an external computing device may be input to the inkjet printer 100 through communication on the display unit 5 of the inkjet printer 100. Alternatively, by recording the printable excitation voltage conditions of the second nozzle calculated by an external calculation device on an information recording medium such as a bar code, QR code, or IC tag, it can be recorded in the reading unit 7 of the inkjet printer 100. Information regarding the LV diagram of the second nozzle may be read from the information recording medium. In such an example, since the LV diagram of the nozzle 211 (second nozzle) attached to the print head of the inkjet printer 100 can be obtained at another location, the configuration of the control unit 200 of the inkjet printer 100 can be becomes easier.

[Example 2]
Next, Example 2 of the present invention will be described using FIG. 11. FIG. 11 is a diagram for schematically explaining Example 2 of the present invention. In the second embodiment, the second nozzle whose excitation voltage condition was estimated and calculated in the first embodiment is attached to the print head 102 of another inkjet printer 110, and printing is performed by the other inkjet printer 110. Note that the arrow indicated by a broken line in FIG. 11 visually indicates that the nozzle 211 is attached to the print head 102 of the inkjet printer 110. Further, the arrow pointing from the inkjet printer 100 to the inkjet printer 110 represents inputting (setting) data of excitation voltage conditions for printing in the nozzle 211 to the inkjet printer 110, and the actual configuration is different.

The operation of the second embodiment shown in FIG. 11 is as follows. First, a printing operation is performed in the inkjet printer 100 by applying a predetermined excitation voltage condition, and the excitation voltage condition under which printing is possible at the nozzle 211 is measured by the method described in Example 1.

Next, the nozzle 211 used in the print head 2 is attached to the print head 102 of another inkjet printer 110. Then, printing is performed by applying the printable excitation voltage conditions regarding the nozzle 211 measured by the inkjet printer 100 to the inkjet printer 110. That is, the excitation voltage conditions for the nozzle 211 that allow printing are input and set to the control unit 120 of the inkjet printer 110, and a printing operation is executed. Data may be input to the control unit 120 by any method. For example, the printable excitation voltage conditions regarding the nozzle 211 may be input to the control unit 120 using a memory. Furthermore, if communication is possible between the printers, the information may be input via communication from an external device (for example, a server).

In such a configuration, since the excitation voltage conditions that allow printing regarding the nozzle 211 (second nozzle) are measured, there is no need to measure the excitation voltage conditions that allow printing in the inkjet printer 110 again. In other words, once the printing-enabled excitation voltage conditions for the nozzle 211 are calculated, the nozzle 211 can be installed in another inkjet printer and a printing operation can be performed. Therefore, it is not necessary to have a configuration in each printer for measuring the LV characteristic regarding the nozzle 211 and calculating the printable excitation voltage condition for the nozzle 211 using the LV characteristic. can. A comparison was made between a case where printing is executed under excitation voltage conditions using such a configuration and a case where printing is executed by calculating an excitation voltage condition that allows printing even in the inkjet printer 110, but it is found that the printing quality is It was confirmed that printing was possible with almost the same printing quality.

[Example 3]
Next, Example 3 of the present invention will be described. Since the third embodiment basically has the same configuration as the first embodiment, the explanation will focus on the points that are different from the first embodiment, and detailed explanation using the drawings will be omitted.

The difference between the third embodiment and the first embodiment is as follows. In this third embodiment, the excitation voltage value Vm2 at the minimum point of the LV diagram of the second nozzle is obtained in advance by the inkjet printer 100. When attaching the second nozzle to the separate inkjet printer 110, the nozzle attaching sequence is selected and executed on the display section 5, and the value of Vm2 is input according to the instructions on the display section 5. The inkjet printer 110 calculates the printable excitation voltage range of the second nozzle in the control unit 120 of the inkjet printer 110 based on the data of the reference nozzle already stored and the input value of Vm2. This is used as the print setting condition of 110.

[Example 4]
Next, Example 4 of the present invention will be described. The fourth embodiment basically has the same configuration as the third embodiment, so the description will focus on the points that are different from the third embodiment. Note that a detailed explanation using the drawings will be omitted for Example 4 as well.

The difference between the fourth embodiment and the third embodiment is as follows. In the fourth embodiment, first, the excitation voltage value Vm2 at the minimum point of the LV diagram of the second nozzle obtained in advance by the inkjet printer 110 is recorded in a QR code, read by the reading unit 7 of the inkjet printer 100, and controlled. The information is stored in the memory within the unit 200. In the control unit 200, from the stored value of Vm2, the excitation voltage calculation unit 274 of the inkjet printer 100 estimates the excitation voltage range in which the second nozzle can print, and uses it as a print setting condition of the inkjet printer 100. .

[Example 5]
Next, Example 5 of the present invention will be described using FIG. 12. FIG. 12 schematically shows the configuration of a printing system according to a fifth embodiment of the present invention.

In FIG. 12, a server 501 is connected to an inkjet printer 100 via a communication line 502 such as an Internet line. The server 501 stores printable excitation voltage conditions regarding the second nozzle used (installed) in the inkjet printer 100 together with the number corresponding to the second nozzle. Note that the serial number of the inkjet printer 100 may be used instead of the number corresponding to the second nozzle. In short, the search data for searching data may be any data as long as it can link the nozzle (second nozzle) used in the inkjet printer 100 and the excitation voltage conditions under which it can print. The printable excitation voltage conditions of the second nozzle stored in the server 501 can be obtained at the time of manufacturing the nozzle or at an appropriate time thereafter. That is, at the time of manufacturing, the printable excitation of each nozzle is determined from the known data of the reference nozzle (LV characteristics and printable excitation voltage conditions) and the L-V characteristics of the manufactured nozzle. The voltage conditions are calculated and stored in the server 501.

Here, the server 501 may be installed anywhere. That is, the server may be installed on the manufacturer's side, as part of the customer's management system, or as a server in a cloud system.

In the configuration shown in FIG. 12, when performing printing, the inkjet printer 100 can perform printing using the nozzle (second nozzle) attached to its own print head, which is stored (saved) in the server 501, which is an external device. The excitation voltage conditions are obtained from the server 501. Specifically, by operating the display device of the inkjet printer 100 (see display unit 5 in FIG. 1), inputting the serial number (search data) of the own nozzle (second nozzle), and communicating from the inkjet printer 100. A data transmission request is made to the server 501 via the line 502. Upon receiving this request, the server 501 retrieves (searches for) the printable excitation voltage conditions of the corresponding second nozzle from the transmitted serial number of the second nozzle, and extracts (searches) the retrieved data (printable excitation voltage conditions of the second nozzle). excitation voltage conditions) are transmitted to the control unit 200 of the inkjet printer 100 via the communication line 502. The control unit 200 of the inkjet printer 100 executes printing based on the transmitted excitation voltage conditions.

In the above embodiment, the server 501 stores the printable excitation voltage conditions for the second nozzle, but the LV line extracted from the LV diagram measurement results of each second nozzle It may also be stored in a form in which the excitation voltage Vm2 at the minimum point showing the characteristics of the diagram or LV diagram is linked. In that case, the LV diagram in the second nozzle or the excitation voltage Vm2 at the minimum point showing the characteristics of the LV diagram is transmitted to the inkjet printer 100, and the second nozzle can print inside the inkjet printer 100. The excitation voltage conditions will be calculated.

That is, when storing the LV diagram of the second nozzle or the minimum point indicating the characteristics of the LV diagram in the server 501, the inkjet printer 100 uses the self-minimum point stored (saved) in the server 501. Data regarding the nozzles attached to the print head (LV diagram or minimum points indicating the characteristics of the LV diagram) is obtained from the server 501. To obtain data, as described above, the inkjet printer 100 sends a data transmission request to the server 501 and obtains the data from the server 501. The server 501, which received this transmission request, searches for the corresponding data (Vm2 value) of the second nozzle from the transmitted serial number of the second nozzle, and uses the search result, the Vm2 value of the second nozzle, as It is transmitted to the inkjet printer 100 via the communication line 502. Thereby, the inkjet printer 100 can calculate the printable excitation voltage range of the second nozzle (nozzle 211) using the excitation voltage calculation unit 274 of the inkjet printer 100 from the received value of Vm2.

DESCRIPTION OF SYMBOLS 1... Main body, 2... Print head, 4... Cable, 5... Display part, 7... Reading part, 100... Inkjet printer, 110... Inkjet printer, 101... Main body, 102... Print head, 120... Control part, 200... Control 201...MPU, 202...ROM, 203...RAM, 204...input panel, 205...display control unit, 206...bus line, 207...charged voltage generation circuit, 208...excitation voltage generation circuit, 209...storage device, 210 ...Optimum phase detection circuit, 211... Nozzle, 213... Charged electrode, 214... Deflection electrode, 215... Gutter, 221... Ink column, 232a, 232b... Piping, 233... Recovery pump, 234... Charge amount measurement unit, 240... Ink Tank, 241, 242... Ink, 245... Circulation pump, 246... Pressure reducing valve, 250... Filter, 251... Auxiliary ink tank, 252... Intensification liquid tank, 260... Conveyance device, 261... Printed object, 262... Rotary encoder , 271...Camera, 272...Strobe lighting, 273...Characteristics measurement section, 274...Excitation voltage calculation section, 501...Server, 502...Communication line

Claims (12)

A nozzle that continuously generates ink particles, a charging electrode that charges the ink particles with an electric charge corresponding to the printed content, a deflection electrode that deflects the charged ink particles, and a gutter that captures the ink particles that are not used for printing. An inkjet printer comprising: a print head having a main body; a main body for supplying ink to the nozzles and collecting ink captured by the gutter; and a control unit for controlling the print head and the main body.
The control unit includes:
storing LV characteristics representing the relationship between the ink cutting position and the excitation voltage in the reference nozzle and the excitation voltage conditions that allow printing;
measuring the LV characteristic in the nozzle;
Calculating the excitation voltage condition that allows printing in the nozzle based on the relative positional relationship between the LV characteristic of the reference nozzle and the LV characteristic of the nozzle and the excitation voltage condition of the reference nozzle;
An inkjet printer that controls the print head based on the calculated excitation voltage condition of the nozzle. The inkjet printer according to claim 1,
An inkjet printer characterized in that the LV characteristic is represented by a graphical LV diagram. The inkjet printer according to claim 1,
The inkjet printer is characterized in that the control unit calculates the excitation voltage condition that allows the nozzle to print using a local minimum point or a local maximum point included in the LV characteristic. The inkjet printer according to claim 1,
The inkjet printer is characterized in that the cutting position is measured using an image taken by a camera. The inkjet printer according to claim 1,
An inkjet printer characterized in that the LV characteristic is determined using a value obtained by plotting an integrated value of a phase difference between excitation voltage conditions against the excitation voltage instead of the cutting position. The inkjet printer according to claim 1,
The excitation voltage condition of the nozzle is supplied from an external memory or an external server that stores the excitation voltage condition of the nozzle calculated in advance, instead of being calculated by the control unit. printer. A nozzle that continuously generates ink particles, a charging electrode that charges the ink particles with an electric charge corresponding to the printed content, a deflection electrode that deflects the charged ink particles, and a gutter that captures the ink particles that are not used for printing. A method for controlling an inkjet printer, comprising: a print head having a main body; a main body for supplying ink to the nozzles and collecting the ink particles captured by the gutter; and a control section for controlling the print head and the main body. hand,
storing LV characteristics representing the relationship between the ink cutting position and the excitation voltage in the reference nozzle and the excitation voltage conditions that allow printing;
Measuring the LV characteristic representing the relationship between the cutting position of the ink ejected from the nozzle and the excitation voltage,
Calculating the excitation voltage condition that allows printing in the nozzle based on the relative positional relationship between the LV characteristic of the reference nozzle and the LV characteristic of the nozzle and the excitation voltage condition of the reference nozzle;
A method for controlling an inkjet printer that performs printing based on the calculated excitation voltage condition for the nozzle. The method for controlling an inkjet printer according to claim 7,
A method for controlling an inkjet printer, characterized in that the LV characteristic is represented by a graphical LV diagram. The method for controlling an inkjet printer according to claim 7,
A method for controlling an inkjet printer, wherein the relative positional relationship is obtained using a local minimum point or a local maximum point included in the LV characteristic. The method for controlling an inkjet printer according to claim 7,
8. The method of controlling an inkjet printer according to claim 7, wherein the cutting position is measured using an image taken by a camera. The method for controlling an inkjet printer according to claim 7,
A method for controlling an inkjet printer, characterized in that the LV characteristic is determined using, instead of the cutting position, a value obtained by plotting an integrated value of phase differences between excitation voltage conditions against the excitation voltage. A nozzle that continuously ejects ink particles, a charging electrode that charges the ink particles with an electric charge corresponding to the printed content, a deflection electrode that deflects the charged ink particles according to the amount of charge, and the ink that is not used for printing. An inkjet printer having a printhead having a gutter for trapping particles, a main body supplying ink to the nozzles, and a controller controlling the printhead and the main body.
The LV characteristic indicating the relationship between the ink cutting position and the excitation voltage of the reference nozzle and the excitation voltage conditions that allow printing are stored, the LV characteristic of the ink ejected from the nozzle is measured, and the LV characteristic of the ink ejected from the reference nozzle is measured. and an arithmetic device that calculates a printable excitation voltage condition of the nozzle based on the relative positional relationship between the LV characteristic of the nozzle and the LV characteristic of the nozzle, and the excitation voltage condition of the reference nozzle,
The control unit is a printing system that controls the print head by inputting the calculated excitation voltage at the nozzle that allows printing.

Images