Inkjet printer and method for controlling an inkjet printer

Abstract

To provide an inkjet printer having a function of automatically sensing a state change of ink accompanying elapse of the time of printing on the basis of an actually printed state.SOLUTION: The inkjet printer comprises: a printing head which includes a charged electrode for applying an electric charge amount corresponding to a printing character to ink particles, a deflection electrode that causes deflection according to the electric charge amount in the ink particles passed through the charged electrode, and a gutter for capturing uncharged ink particles that are not used in printing; a control part that supplies charged voltages to the charged electrode on the basis of a character pattern corresponding to printing character information; and an inspecting device that takes in a result printed on an object to be printed, as an image, and inspects a printed state. The inspecting device calculates a dot position deviation between a dot position in a noticed dot determined for each printing character and a target position of the noticed dot, stores the calculated dot position deviation in a chronological order, and determines an ink state of ink in use on the basis of the stored dot position deviation.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an inkjet printer and a method for controlling an inkjet printer.

Background Art

[0002] Industrial inkjet printers atomize ink, give the ink particles an electric charge corresponding to the printed characters, and further give a deflection corresponding to the electric charge to fly the ink particles onto a printing object (such as a product) for printing. In such an inkjet printer, when an electric charge is given to (charged) the ink particles corresponding to the printing pattern constituting the printed characters, a deviation in the landing position of the ink particles that have landed on the printing object occurs due to fluctuations in the Coulomb force generated between the flying ink particles, resulting in a deterioration in print quality. To prevent such a deterioration in print quality, various techniques have been proposed. For example, Japanese Patent Application Laid-Open No. 2005-35210 (Patent Document 1) discloses one technique for solving such problems.

[0003] This Patent Document 1 describes that "immediately before injecting the charge target ink particles among the ink particles capable of landing, which are injected until immediately before injecting the charge target ink particles, the number a of the chargeable ink particles A capable of landing charged among the ink particles capable of landing within the set reference number from the charge target ink particles, and the number b of the non-charged ink particles B capable of landing that are not charged and exist between the charge target ink particles and the chargeable ink particles A capable of landing charged immediately before the charge target ink particles are read from the print information stored in the storage means, and a charge amount correction means for correcting the charge amount based on correction data corresponding to the number a and the number b stored in the storage means in advance is provided."

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] According to the technology of Patent Document 1 described above, since the charge amount is corrected based on the stored correction data corresponding to the number of charged ink particles and the number of non-charged ink particles from the stored print information, high-quality printing can be obtained.

[0006] However, even if high-quality printing was initially achieved, as the operating time of the inkjet printer increases, the state of the ink changes due to foreign matter mixing into the ink during use or the deterioration of the ink itself over time, resulting in a change in the charging rate. Also, due to the adhesion of ink droplets to the device, it may become impossible to stably maintain high-quality printing. As a countermeasure against the deterioration of print quality associated with such long-term operation, methods such as having maintenance personnel regularly check for ink discoloration or whether the ink has been used for more than a predetermined time and replacing the ink have been adopted. However, it is difficult for maintenance personnel to accurately detect the deterioration state of the ink during maintenance inspections, and it is also very difficult to perform maintenance inspections regularly.

[0007] Therefore, an object of the present invention is to provide an inkjet printer and an inkjet printer control method that can automatically detect changes in the state of ink over time based on the actually printed state.

Means for Solving the Problems

[0008] In order to solve the above problems, an example of the present invention is an inkjet printer including an ink nozzle that atomizes ink and ejects ink particles, a charging electrode that imparts an electric charge amount corresponding to a printed character to the ink particles, a deflection electrode that causes a deflection corresponding to the electric charge amount to occur in the ink particles that have passed through the charging electrode and makes them fly toward a printing object, and a gutter that collects non-charged ink particles not used for printing, a control unit that stores printed character information, calculates a charging voltage for imparting the electric charge amount based on a character pattern corresponding to the printed character information, and controls the charging electrode, and is provided with an inspection device that captures the result of printing on the printing object as an image and inspects the printing state using the image. The inspection device calculates a dot position deviation between a printed dot position of a target dot determined for each printed character and a target position of the target dot, stores the dot position deviation in time series, and determines the ink state of the ink based on the stored dot position deviation.

[0009] Also, another example of the present invention is a control method for an inkjet printer including an ink nozzle that atomizes ink and ejects ink particles, a charging electrode that imparts an electric charge amount corresponding to a printed character to the ink particles, a deflection electrode that causes a deflection corresponding to the electric charge amount to occur in the ink particles that have passed through the charging electrode and makes them fly toward a printing object, and a gutter that collects non-charged ink particles not used for printing, and a control unit that stores printed character information, calculates a charging voltage for imparting the electric charge amount based on a character pattern corresponding to the printed character information, and controls the charging electrode. The method includes capturing the result of printing on the printing object as an image, obtaining a dot position at a target dot determined for each printed character from the image, calculating a dot position deviation that is the deviation between the dot position and a target dot position at the target dot, storing the dot position deviation in time series, and determining the ink state of the ink based on the stored dot position deviation.

Advantages of the Invention

[0010] According to the present invention, it is possible to provide an inkjet printer and a control method for an inkjet printer that enable the state of ink in use to be estimated and determined from the actual printing state.

Brief Description of the Drawings

[0011]

Fig. 1

Fig. 2

Fig. 3

Fig. 4

Fig. 5

Fig. 6

Fig. 7

Fig. 8

Fig. 9

Fig. 10

Modes for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the present invention is not construed as being limited to the description of the embodiments described below. Those skilled in the art can easily understand that the configuration can be changed without departing from the technical idea or gist of the present invention. In addition, in the configuration of the embodiments described below, the same reference numerals are commonly used among the drawings for the same device or parts having the same or similar functions, and duplicate descriptions may be omitted. Also, the positions, sizes, shapes, ranges, etc. of each configuration shown in the drawings do not represent the actual positions, sizes, shapes, ranges, etc. in order to facilitate the understanding of the invention. Therefore, the present invention is not limited to the positions, sizes, shapes, ranges, etc. of the constituent devices disclosed in the drawings.

[0013] <<Example 1>> First, Example 1 of the present invention will be described with reference to FIGS. 1 to 6. FIG. 1 is an external view of the entire inkjet printer. FIG. 2 is a diagram showing the schematic configuration of the inkjet printer. FIG. 3 is a diagram showing the system configuration of the entire inkjet printer in Example 1 of the present invention. FIG. 4 is an example of an operation flowchart for determining a target dot. FIG. 5 is a diagram showing the main functions in Example 1. FIG. 6 is an example of statistical information on variations for determining the ink state.

[0014] First, with reference to FIGS. 1 and 2, the schematic configuration and printing control of the inkjet printer in Example 1 of the present invention will be described.

[0015] In FIG. 1, an inkjet printer includes a printing head 2 that receives ink supply and performs printing, and a device main body 1 that supplies printing ink to the printing head 2 and recovers the ink that has not been used for printing from the printing head 2. A cable 5 connects between the device main body 1 and the printing head 2. The device main body 1 also includes a control unit 3 inside. This control unit 3 executes ink supply control of the device main body 1, printing control (charging control) of the printing head 2, etc. The operation / display unit 4 is arranged on the front surface of the device main body 1 and has a function of displaying information related to printing and inputting information such as printed characters to the control unit 3. A touch panel or the like is used for the operation / display unit 4.

[0016] The printing head 2 performs predetermined printing (printing data stored in advance in the control unit 3) on a printing object 10 such as a product that moves on a conveying device 6 such as a belt conveyor. The arrow in the figure indicates the moving direction of the printing object 10. When the printing object 10 reaches the printing position, the control unit 3 controls the printing head 2, and the printing head 2 performs printing on the printing object 10.

[0017] Next, the printing principle of the inkjet printer will be described with reference to FIG. 2. In FIG. 2, the devices with the same reference numerals as in FIG. 1 indicate the same devices. First, the device main body 1 includes an ink container 11 that stores (holds) ink a, an ink supply pump 12 for supplying ink a to the printing head 2, and an ink recovery pump 13 for recovering the ink that has not been used for printing into the ink container 11.

[0018] The printing head 2 includes an ink nozzle 21 for atomizing and ejecting the ink fed from the apparatus main body 1. The ink nozzle 21 is provided with a vibrator (piezoelectric element), and by applying a periodic voltage to the piezoelectric element, the ink in the ink nozzle 21 is excited. As a result, the ink is ejected from the ink nozzle 21 as an ink column b and ejected as ink particles. Further, the printing head 2 includes a charging electrode 22 that applies a charge corresponding to the printing content to the passing ink particles, a deflection electrode 23 that causes a deflection corresponding to the charge amount to the charged ink particles c and makes them fly toward the printing object 10, and a gutter 24 for collecting the ink particles d not used for printing.

[0019] The deflection electrode 23 generates an electrostatic field between the positive electrode and the negative electrode to deflect the passing ink particles. As a result, the charged ink particles c used for printing fly and land (liquefy) toward the printing object 10 to execute printing. On the other hand, the uncharged ink particles d not used for printing travel straight through the deflection electrode 23 and are collected by the gutter 24. The ink collected by the gutter 24 is recovered into the ink container 11 by the ink recovery pump 13. The recovered ink is reused for printing.

[0020] The control unit 3 has a function of supplying a charging voltage to the charging electrode 22 of the printing head 2 to perform printing control (charging control), and a main body control function of performing drive control of pumps and the like in the apparatus main body 1. Hereinafter, the printing control in the printing head 2 and the configuration and operation of a configuration that inputs the printed result (printing result) and executes ink state determination will be mainly described.

[0021] Next, with reference to FIG. 3, the configuration and operation of the first embodiment of the present invention having a function of determining the state of ink based on the printing result will be described. First, in FIG. 3, devices with the same reference numerals (numbers) as those in FIGS. 1 and 2 represent the same devices as in FIGS. 1 and 2. Therefore, the operation descriptions of the devices already described may be omitted. Also, although the control unit 3 and the inspection device 7 in the first embodiment of the present invention can be realized by hardware having the functions of a computer, here, for the sake of easy understanding of the first embodiment, the internal configurations of the control unit and the inspection device will be described by showing them in block diagrams.

[0022] In FIG. 3, the control unit 3 inputs the content (print data) to be printed on the printing object 10 from the operation / display unit 4 and stores it in an internal memory (not shown). The attention dot determination unit 32 of the control unit 3 determines an attention dot based on the print data 31 stored in this memory.

[0023] Here, the "attention dot" is a dot selected from any of the M rows × N columns of print dots that make up the printed character. Basically, one attention dot per character is sufficient, but multiple attention dots are also acceptable. In the following description, it is assumed that one attention dot is determined per character. The attention dots in this first embodiment select dots that are less affected by the Coulomb force acting on the flying ink particles, as will be described later. However, the present invention is not limited to this, and any dot can be selected as the attention dot. Also, in the first embodiment, the configuration is such that the print data is captured and the attention dots are determined online. However, once the print data (the characters to be printed) is determined, predetermined dots for each of those characters may be determined (selected) as the attention dots.

[0024] In FIG. 3, the charging voltage control unit 33 of the control unit 3 is provided to control the amount of charge applied to the ink particles for each dot constituting the printing, and supplies the charging voltage applied to the flying ink particles to the charging electrode 22. Further, the dot sharing unit 34 is provided to share the information of the target dot determined by the target dot determination unit 32 with the inspection device 7. Further, the correction information input unit 35 is provided to input the correction information (charging control correction value) required by the inspection device 7. The charging voltage control unit 33 executes correction control of the charging voltage for applying charges to the moving ink particles based on this correction information.

[0025] The inspection device 7 is provided to capture the printing result printed on the printing object 10 by the print head 2 as an image and inspect the printing state (judge whether the printing state is acceptable) based on this image. In this first embodiment, it further has a function of judging the state of the ink and a correction value calculation function. The camera 70 captures an image of the printed printing object 10 conveyed by the conveying device 6 and supplies it to the inspection device 7 as an image.

[0026] The inspection device 7 is provided with an image processing unit 71, which captures the image captured by the camera 70 and outputs the printing state by image processing. The image processing unit 71 processes the printing situation so that it can be judged in units of printed dots. Note that image processing is a process of removing noise and the like from the image and performing feature extraction and image recognition of the image. These are well-known matters, and detailed explanations are omitted here.

[0027] The dot position deviation acquisition unit 72 is provided to obtain the printing position deviation (dot position deviation) between the dot position of the target dot obtained by the image processing by the image processing unit 71 from the printing result and the planned printing position (target dot position) of the target dot.

[0028] The correction information calculation unit 73 calculates correction information (correction value) for eliminating (reducing) the deviation based on the dot position deviation of the dot position deviation acquisition unit 72.

[0029] Specifically, the correction value is determined from the difference between the planned landing coordinates (target dot position) of the dot of interest and the absolute position of the acquired dot. When determining the correction value, the influence of relative coordinates is considered. Relative coordinates are necessary for correcting the displacement of the entire character. In an inkjet printer, the entire character may be displaced due to the displacement of the printing target or the imaging timing of the inspection device. In this case, although an absolute value displacement also occurs, since this is not caused by factors such as ink deterioration, this influence is excluded from the determination. The correction value is mainly performed in the form of correction for the applied voltage value. When the charging rate decreases due to ink deterioration, even if the assumed charge is applied, the landing position will be lower than expected. To correct this, it is necessary to apply a higher charging voltage to the ink.

[0030] As described above, the calculated correction information is supplied to the charging voltage control unit 33 via the correction information input unit 35 of the control unit 3 and is used for the correction control of the charging voltage.

[0031] Now, the dot position deviation at the dot of interest obtained in the dot position deviation acquisition unit 72 is supplied to the ink state determination unit 74. The ink state determination unit 74 stores the dot position deviation at the input dot of interest in time series and determines the state of the ink in use based on the stored dot position deviation. That is, it is determined whether the state of the ink in use has deteriorated due to long-term use or the like and it is time to replace the ink. Specifically, in this Example 1, the dot position deviations for the past N times stored in time series are statistically processed to determine the ink state. For example, when the variation is large, it is determined that the ink deterioration has progressed, thereby determining the ink state.

[0032] Then, as a result of the determination by the ink state determination unit 74, when it is determined that the ink state has deteriorated to the state where ink replacement should be performed, or when it is determined that the ink state is approaching the state where ink replacement should be performed, the warning information is output via the warning output unit 75. The warning information is displayed on a display unit (not shown) provided in the inspection device or transmitted (output) to the outside for transmission to a monitoring center or the like (not shown).

[0033] Next, a specific example of the method for determining the dot of interest in the dot-of-interest determination unit 32 will be described with reference to FIG. 4. Note that the determination of the dot of interest is not limited to the method described here.

[0034] In FIG. 4, when the printing data 31 is input, the processes of steps S01 to S08 are performed, and the dot of interest in each printed character is determined. In step S01, one character in the printing data is selected, and in step S02, any one of the dots constituting the selected character is selected.

[0035] In step S03, the dot position score of the selected dot is obtained. By determining scores in advance for each dot constituting each printed character, the dot position scores of the respective dots can be obtained. The method of determining these scores is performed as follows, for example. That is, in order for the printing head to print the upper dot, it is necessary to apply a larger charging voltage to greatly change the flight path of the ink particles. Therefore, the upper dot has the characteristic of being vulnerable to disturbance and being easily disturbed. Therefore, in order to eliminate the influence of disturbance and extract only the change over time, an algorithm that makes the lower dot more likely to be selected as the dot of interest is used. Specifically, the dot position score is determined such that the score of the lower dot is higher. For example, if the height direction of printing is 10 dots, the scores are determined to be 1 point... 10 points from the topmost row. Finally, normalization is performed so that the influence contributing to the dot of interest is equal in each score part. In the case of the previous example, a process of dividing by 10 is finally performed.

[0036] Next, in step S04, scores are given considering the influence of merge scatterers. Merge scatterers are a phenomenon in which the flight paths of ink particles in flight change due to the influence of the Coulomb force between the ink particles. When the dots to be printed are continuous in the vertical direction, they are easily affected by merge scatterers, and the stability of the printed dots decreases. Therefore, a point deduction process is performed on the dots with dots before and after them. In theory, all ink particles in flight affect each other, but in this embodiment, only the three dots before and after are targeted. When there are dots immediately before and after, -3 points are given to each, and -2 points and -1 point are added for each additional dot separation. Finally, normalization processing is performed.

[0037] Next, in step S05, scores are given based on the relative position with respect to the target dot in the previous (previously printed) printed character. Relative position information of each target dot is required to detect the deviation of the target dot. At that time, the amount of information that can be obtained increases as the relative position becomes larger, so points are added according to the size of the relative position. In this embodiment, 1 point is added for each dot separation in the relative position. Finally, normalization is performed.

[0038] In step S06, it is determined whether the processing of steps S03 to S05 for all the dots constituting the character selected in step S01 has been completed. If there are still unprocessed dots (in the case of NO), the process returns to step S02 and repeats until the processing of all dots is completed. When the processing of all the dots in the character selected in step S01 is completed (in the case of YES), the process proceeds to step S07.

[0039] In step S07, the scores of all the dots in the character selected in step S01 are totaled, the dot with the highest score among them is obtained, and the dot with this highest score is selected (determined) as the "target dot" in that character.

[0040] In step S08, it is determined whether the selection of the attention dots for all the printed characters has been completed. If the selection of the attention dots for all the characters has not been completed (in the case of NO), the process returns to step S01, the remaining characters are selected, and the processes of steps S02 to S07 described above are executed for the newly selected characters.

[0041] Then, in step S08, when the selection of the attention dots has been completed for all the characters, this operation ends. In this way, one attention dot can be selected for each printed character.

[0042] In addition, in FIG. 4, the dot position scores, merge scatter scores, and previous character relative position scores for each dot constituting the printed character are obtained respectively, and the total value thereof is used for attention dot determination. However, the attention dot may be determined using a part of these scores. For example, the sum of the dot position score and the merge scatter score may be used. In the attention dot determination unit 32 of FIG. 3, one attention dot is determined for each character to be printed by the method described above.

[0043] Next, the main functions of the inspection device 7 shown in FIG. 3 will be described with reference to FIG. 5. The dot position deviation acquisition function 100 is the function of the dot position deviation acquisition unit 72 in FIG. 3. The position deviation at the attention dot obtained by the dot position deviation acquisition function 100 is input to the correction information determination function 110 that calculates the correction value and the ink state determination function 130. The correction information determination function 110 determines the correction value and outputs it to the correction control function 120. The correction control function 120 executes the correction control in the charging control. The ink state determination function 130 stores the dot position deviation at the attention dot in time series, and based on the stored dot position deviation data, determines the state of the ink in use. Specifically, for example, the ink state is determined by looking at the degree of variation in the dot position deviation in the past N times. And if it is determined that ink replacement is necessary as a result of this ink state determination, the determination result is given to the ink replacement warning function 140. Thereby, the ink replacement warning function 140 issues a warning.

[0044] Next, a specific example of the ink state determination method in the ink state determination unit 74 of FIG. 3 will be described with reference to FIG. 6. This determination is made using the dot position deviation at the past target dots stored in time series. That is, when the dot position deviations stored in time series are referred to, for example, the past 10 times, and the number of dot position deviations that exceed the threshold value is counted, it is determined that the ink should be replaced and a warning is issued. Of course, multiple methods can be considered for ink state determination, and methods other than this method may also be used. That is, it can be realized by using the dot position deviation of the target dots stored in time series and performing ink deterioration determination by a known statistical method.

[0045] As described above, according to the first embodiment of the present invention, a target dot is determined for each printed character, and a dot position deviation, which is the deviation between the dot position of the target dot extracted from the character actually printed on the printing object and the target dot position, is obtained. Based on this dot position deviation, a correction value for charge control is obtained to perform print correction control, and this dot position deviation is stored in time series. Based on the stored dot position deviation, the state of ink deterioration can be determined. Further, when the determined ink state reaches a level where ink replacement is necessary (including the case where it is approaching the level where ink replacement is required), a warning for prompting ink replacement can be issued. Thereby, the work of ink maintenance inspection can be reduced.

[0046] ≪Second Embodiment≫ Next, the second embodiment of the present invention will be described with reference to FIG. 7. FIG. 7 is a diagram showing the system configuration of the entire inkjet printer in the second embodiment of the present invention.

[0047] First, this second embodiment has basically the same functions as the first embodiment shown in FIG. 3, and its configuration is also almost the same. Therefore, in the second embodiment, detailed description will be omitted, and the description will focus on the differences from the first embodiment.

[0048] In the case of Example 1, the inspection device 7 was provided, and the inspection device 7 obtained the dot position deviation at the dot of interest, performed the calculation of the correction value, and determined the ink state.

[0049] On the other hand, in Example 2 shown in FIG. 7, the inspection device 7 is not provided, and the difference from Example 1 is that all the functions of the arithmetic processing performed by the inspection device 7 are performed within the control unit 3.

[0050] Also in Example 2 of the present invention, it has the same effect as Example 1. Furthermore, in this Example 2, since the functions performed by the inspection device are executed within the control unit 3 for printing, the overall configuration can be made compact.

[0051] ≪Example 3≫ Next, Example 3 of the present invention will be described with reference to FIGS. 8 and 9. FIG. 8 is a diagram showing the system configuration of the entire inkjet printer in Example 3 of the present invention. FIG. 9 is a flowchart for explaining the method of determining the dot of interest in Example 3.

[0052] First, the configuration of Example 3 shown in FIG. 8 is almost the same as that of Example 1 (FIG. 3), but there are some differences. When the reference numerals (numbers) attached to each device constituting FIG. 8 are the same as the reference numerals (numbers) attached to each device in FIG. 3, they are devices having the same function. Therefore, detailed descriptions of these devices will be omitted. Similarly, in the flowchart of determining the dot of interest shown in FIG. 9, the same reference numerals are given to the same processing operations as in the case of FIG. 4, and the description thereof will be omitted. Hereinafter, in Example 3, the description will be centered on the differences from Example 1.

[0053] In the third embodiment, even when the printing is relatively stable, it is possible to detect and correct a decrease in printing quality due to dot position deviation at the target dot. That is, in the first embodiment, when selecting the target dot, a stable dot that is less affected by disturbances is selected. However, for example, when the printing speed is low, the influence of disturbances is reduced, and if a stable dot is selected, it may be difficult to compensate for the influence of ink deterioration or the like. Therefore, in the third embodiment, the printing stability is input from the outside, and the point algorithm is corrected based on this.

[0054] In FIG. 8, the fact that the printing stability 36 is stored in a memory (not shown) in the control unit 3 is a part that is different from the configuration of the first embodiment. In the third embodiment, the printing stability 36 is set from the operation and display unit 4. In addition to this method, it is also possible to input parameters such as the line speed and create a parameter called printing stability from there.

[0055] FIG. 9 shows a flowchart for determining the target dot using the printing stability. Compared with FIG. 4 which is the flowchart in the first embodiment, a step S10 of using the printing stability in the calculations of steps S03 to S05 is added. Based on this, the method of adding points to each point part is changed. For example, in step S03 of obtaining the dot position points, the dot position with the highest points is changed according to the printing stability. In the first embodiment, the lowest dot was set to have the highest points, but here, according to the stability, the upper dots are set to have the highest points, and an algorithm is used to add 1 point less for each dot separated by 1 dot from there. Similarly, in steps S04 and S05, points considering the printing stability are set, and based on this, the points of each dot are obtained.

[0056] According to the third embodiment described above, it is possible to have the same effects as the first embodiment, and it is also possible to detect and correct a decrease in printing quality due to the target dot even when the printing is stable.

[0057] ≪Fourth Embodiment≫ Next, Example 4 of the present invention will be described with reference to FIG. 10. FIG. 10 is a diagram showing the system configuration of the entire inkjet printer in Example 4 of the present invention. This Example 4 has substantially the same configuration as that shown in FIG. 3 of Example 1, but is different in that a print image transmission unit 76 for transmitting the print image to the outside is provided. Other configurations and functions are the same as those in Example 1. Hereinafter, the description will focus on the configuration different from that of Example 1.

[0058] In FIG. 10, the inspection device 7 obtains the dot position deviation at the target dot, calculates a correction value, determines the ink state, and outputs warning information when the ink deterioration has advanced beyond a certain level. Further, the inspection device 7 in Example 4 has a function of outputting the image captured by the print image transmission unit 76 from the camera 70 or the image information obtained by subjecting this image to image processing by the image processing unit 71 to an external system such as a service center.

[0059] This eliminates the need for the maintenance staff to communicate the printing status, enabling a more rapid maintenance response. In many cases, the location of component replacement in an inkjet printer can be determined from print distortion. By transmitting this information in advance, more efficient maintenance becomes possible. Also, by transmitting the internal information of the inkjet printer together, it is possible to improve the accuracy of maintenance.

[0060] According to Example 4 described above, it has the same effects as Example 1 and enables more efficient maintenance.

Description of Reference Numerals

[0061] 1... Device body, 2... Printing head, 3... Control unit, 4... Operation / display unit, 5... Cable, 6... Conveyor device, 7... Inspection device, 10... Object to be printed, 11... Ink container, 12... Ink supply pump, 13... Ink recovery pump, 21... Ink nozzle, 22... Charging electrode, 23... Deflection electrode, 24... Gutter, 31... Printing data, 32... Attention dot determination unit, 33... Charging voltage control unit, 34... Dot sharing unit, 35... Correction information input unit, 36... Printing stability, 70... Camera, 71... Image processing unit, 72... Dot position deviation acquisition unit, 73... Correction information calculation unit, 74... Ink state determination unit, 75... Warning output unit, 76... Printed image transmission unit

Claims

1. An inkjet printer comprising: an ink nozzle that atomizes ink to eject ink particles; a charging electrode that imparts an electric charge amount corresponding to a printed character to the ink particles; a deflection electrode that causes the ink particles passing through the charging electrode to be deflected according to the electric charge amount and fly toward a printing object; and a gutter that collects non-charged ink particles not used for printing; a control unit that stores printed character information, calculates a charging voltage for imparting the electric charge amount based on a character pattern corresponding to the printed character information, and controls the charging electrode. An inspection device is provided that captures, as an image, the result of printing on the printing object and inspects the printing state using the image. The inspection device calculates a dot position deviation between the printed dot position of a target dot determined for each printed character and the target position of the target dot, stores the dot position deviation in time series, and determines the ink state of the ink based on the stored dot position deviation.

2. The inkjet printer according to Claim 1, wherein the inspection device calculates correction information for reducing the dot position deviation based on the dot position deviation, and the control unit inputs the correction information and corrects and controls the charging electrode.

3. The inkjet printer according to Claim 1 or 2, wherein the inspection device issues a warning to prompt ink replacement when the ink state is a state where ink replacement should be performed.

4. The inkjet printer according to Claim 1 or 2, wherein the calculation of the dot position deviation in the inspection device, the storage of the dot position deviation in time series, and the determination of the ink state based on the stored dot position deviation are performed by the control unit.

5. In the inkjet printer according to claim 1, the inspection device is characterized in that the inspection device transmits image information obtained from the image to the outside.

6. In the inkjet printer according to claim 1, for each dot constituting the printed character, the number of dot positions, the number of merge scatterers, and the number of relative positions of the previous character are set for the target dot, and one for each printed character is determined based on the sum value of one or more of these numbers of points. An inkjet printer characterized by this.

7. In the inkjet printer according to claim 6, the number of dot positions, the number of merge scatterers, and the number of relative positions of the previous character are changed according to the printing stability. An inkjet printer characterized by this.

8. In the inkjet printer according to claim 1, the ink state is determined based on the variation situation of the dot position deviation of the past N times stored. An inkjet printer characterized by this.

9. An inkjet printer control method including an ink nozzle that atomizes ink and ejects ink particles, a charging electrode that imparts an electric charge amount corresponding to a printed character to the ink particles, a deflection electrode that causes the ink particles that have passed through the charging electrode to be deflected according to the electric charge amount and fly toward a printing object, and a gutter that collects non-charged ink particles that are not used for printing, and stores printed character information, calculates a charging voltage for imparting the electric charge amount based on a character pattern corresponding to the printed character information, and controls the charging electrode, The result of printing on the printing object is captured as an image, the dot position at the target dot determined for each printed character is obtained from the image, the dot position deviation, which is the deviation between the dot position and the target dot position at the target dot, is calculated, the dot position deviation is stored in time series, and the ink state of the ink is determined based on the stored dot position deviation. An inkjet printer control method.

10. In the method for controlling an inkjet printer according to claim 9, correction information for reducing the dot position deviation is calculated based on the dot position deviation, and the charging electrode is corrected and controlled by the correction information. A method for controlling an inkjet printer, characterized by this.

11. In the method for controlling an inkjet printer according to claim 9, when the ink state is a state where ink replacement is to be performed, a warning for prompting ink replacement is given. A method for controlling an inkjet printer, characterized by this.

12. In the method for controlling an inkjet printer according to claim 9, the image information obtained from the image is transmitted to the outside. A method for controlling an inkjet printer, characterized by this.

13. In the method for controlling an inkjet printer according to claim 9, for the target dot, the number of points of the dot position, the number of points of the merge scatterer, and the number of points of the relative position of the previous character are set for each dot constituting the printed character, and one is determined for each printed character based on the total value of one or more of these numbers of points. A method for controlling an inkjet printer, characterized by this.

14. In the method for controlling an inkjet printer according to claim 9, the ink state is determined based on the variation situation of the dot position deviation in the past N times stored. A method for controlling an inkjet printer, characterized by this.

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