Drive signal setting method, liquid ejection head, and image forming apparatus

Abstract

The drive signal setting method includes an adjustment step, a mounting step, and a correction step. In the adjustment step, the voltage of the drive signal of the liquid ejection head is adjusted so that the result of ejection of the predetermined inspection liquid by the liquid ejection head capable of ejecting the liquid becomes a predetermined reference result, and the adjusted voltage is set. In the mounting step, the liquid ejection head after the adjustment step is mounted on the liquid ejection recording apparatus. In the correction step, after the mounting step, the adjustment voltage is corrected using a correction value associated with the discharge liquid discharged from the liquid discharge head, and the corrected voltage is set.

Description

Technical Field

[0001] The present invention relates to a driving signal setting method for setting a driving signal of a liquid ejecting head, and a liquid ejecting head and an image forming apparatus used in the driving signal setting method. Background Art

[0002] Liquid ejection recording devices such as inkjet printers include a liquid ejection head that ejects ink for image formation toward a recording medium. In addition, when the recording medium is a fiber sheet such as a textile or a woven fabric, or a plastic sheet, it is sometimes necessary to apply a treatment liquid to the recording medium in order to improve the fixability of the image formed on the recording medium. In this case, the liquid ejection recording device also includes a liquid ejection head that ejects the treatment liquid.

[0003] The liquid ejection head includes a piezoelectric element such as a pressure (piezo) element, a liquid pressurizing chamber, and a liquid ejection hole. The liquid ejection head pressurizes the liquid filled in the liquid pressurizing chamber by displacing the piezoelectric element, so that the liquid in the liquid pressurizing chamber is ejected from the liquid ejection hole. The piezoelectric element is displaced according to a driving signal representing a pulsed voltage change.

[0004] Patent document 1 discloses that when a liquid ejection head is caused to eject liquid, the liquid ejection head is caused to eject liquid by driving the head based on a driving voltage predetermined according to the viscosity characteristics of the liquid. Patent document 2 discloses that during the factory inspection of the inkjet head, the driving voltage of the inkjet head is measured, the driving voltage is corrected based on the characteristics of the ink used when recording the image, and the corrected driving waveform and driving voltage are set for the inkjet head. In addition, Patent document 2 discloses that the inkjet head is filled with inspection ink, and a printing inspection is performed with the corrected driving voltage.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2005-144785

[0008] Patent Document 2: Japanese Patent Application Publication No. 2005-212475 Summary of the invention

[0009] A driving signal setting method of one embodiment of the present disclosure includes an adjustment process, a mounting process, and a correction process. In the adjustment process, the voltage of the driving signal of the liquid ejection head is adjusted to an adjustment voltage so that the ejection result of a specified inspection liquid ejected by a liquid ejection head capable of ejecting liquid becomes a specified reference result. In the mounting process, the liquid ejection head after the adjustment process is mounted on a liquid ejection recording device. In the correction process, after the mounting process, the adjustment voltage is corrected using a correction value associated with the ejection liquid ejected by the liquid ejection head to be set as a correction voltage.

[0010] In addition, a drive signal setting method according to another embodiment of the present disclosure includes a mounting process and a correction process. In the mounting process, a liquid ejection head is mounted on a liquid ejection recording device, the liquid ejection head being capable of ejecting liquid, and the voltage of the drive signal is adjusted to an adjustment voltage in such a manner that the ejection result of the predetermined inspection liquid ejected by the liquid ejection head becomes a predetermined reference result. In the correction process, after the mounting process, the adjustment voltage is corrected using a correction value associated with the ejection liquid ejected by the liquid ejection head to be set as a correction voltage.

[0011] Furthermore, a liquid ejection head according to another aspect of the present disclosure is capable of ejecting liquid, and includes a storage unit storing a voltage of a drive signal for causing the liquid ejection head to eject a predetermined test liquid so as to obtain a predetermined reference result.

[0012] In addition, an image forming device according to another embodiment of the present disclosure includes a liquid ejection head, a carrying portion, a correction portion, and an image forming portion. The liquid ejection head is capable of ejecting liquid, and the voltage of a driving signal is adjusted to an adjustment voltage in such a manner that an ejection result of a specified inspection liquid becomes a specified reference result. The liquid ejection head is carried on the carrying portion. The correction portion corrects the adjustment voltage to a correction voltage using a correction value associated with the ejection liquid ejected by the liquid ejection head for the driving signal of the liquid ejection head carried on the carrying portion. The image forming portion drives the liquid ejection head with the correction voltage, thereby forming an image on a recording medium using the ejection liquid ejected from the liquid ejection head.

[0013] In addition, an image forming device according to another embodiment of the present disclosure includes a liquid ejection head, a first mounting portion, a second mounting portion, a correction portion, and an image forming portion. The liquid ejection head is capable of ejecting liquid and has a storage portion storing an adjustment voltage, wherein the adjustment voltage is a voltage of a drive signal for ejecting a specified inspection liquid in a manner that becomes a specified reference result. The liquid ejection head includes a first liquid ejection head and a second liquid ejection head. The first liquid ejection head is mounted on the first mounting portion. The second liquid ejection head is mounted on the second mounting portion. The adjustment voltage is a voltage of the drive signal when the density of an image formed on the medium by the inspection liquid ejected from the liquid ejection head to the medium is equal to the density of an image formed on the medium by the inspection liquid ejected from the liquid ejection head by the reference amount, when the ejection amount of the inspection liquid when the liquid ejection head is driven by a standard drive signal for causing the liquid ejection head to eject a specified target amount of ink is set as a reference amount. After the second liquid ejection head is mounted on the second mounting portion, the correction unit corrects the second adjustment voltage stored in the second storage unit of the second liquid ejection head using the correction value associated with the treatment liquid ejected by the second liquid ejection head. After the second liquid ejection head is mounted on the second mounting portion and the first liquid ejection head is mounted on the first mounting portion, the image forming unit causes the first liquid ejection head to eject the ink by the drive signal of the first adjustment voltage stored in the first storage unit of the first liquid ejection head, and causes the second liquid ejection head to eject the treatment liquid by the drive signal of the second adjustment voltage corrected by the correction unit, thereby forming an image on a recording medium. The correction value is the difference between the voltage of the drive signal required to cause the second liquid ejection head to eject the target amount of the treatment liquid and the voltage of the drive signal required to cause the second liquid ejection head to eject the target amount of the ink. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a perspective view showing the overall structure of an image forming apparatus according to one embodiment of the present disclosure.

[0015] Figure 2 yes Figure 1 Schematic cross-sectional view of line II-II.

[0016] Figure 3 yes Figure 1 An enlarged perspective view of the carriage is shown.

[0017] Figure 4 This is a diagram for explaining a driving signal of a liquid ejection head.

[0018] Figure 5A This is a diagram for explaining the ejection principle of liquid from the liquid ejection head.

[0019] Figure 5B This is a diagram for explaining the ejection principle of liquid from the liquid ejection head.

[0020] Figure 5C This is a diagram for explaining the ejection principle of liquid from the liquid ejection head.

[0021] Figure 6 1 is a block diagram showing an electrical configuration of an image forming apparatus according to an embodiment of the present disclosure.

[0022] Figure 7 : is a flowchart showing the flow of the drive signal setting method.

[0023] Figure 8 This is a chart used to determine the baseline amount.

[0024] Fig. 9 This is a diagram showing an example in which the voltages of the drive signals of the first liquid ejection head and the second liquid ejection head, which are different from each other, are adjusted.

[0025] Fig.10 is a graph used to determine correction values.

[0026] Fig.11 is a graph used to determine correction values. DETAILED DESCRIPTION

[0027] The voltage of the driving signal of the liquid ejection head varies from one unit to another. Therefore, in order to use the liquid ejection head after inspection, it is necessary to carry out a complicated operation of carrying the liquid ejection head at a predetermined position in a manner of supplying the liquid assumed to be ejected during inspection. In particular, when a liquid ejection recording device includes a plurality of carrying units for the liquid ejection heads, such as a color inkjet printer, the operation of carrying each liquid ejection head at a predetermined carrying unit among the plurality of carrying units becomes more complicated.

[0028] In the present disclosure, the liquid ejection head can be mounted without complicated work, and the voltage of the driving signal of the liquid ejection head can be adjusted to a voltage suitable for the individual difference of the liquid ejection head and the ejection liquid of the liquid ejection head.

[0029] Hereinafter, the drive signal setting method, liquid ejection head and image forming device of each embodiment of the present disclosure will be described with reference to the accompanying drawings. In the following embodiments, as a specific example of the image forming device, an inkjet printer (liquid ejection recording device) having an inkjet head for ejecting ink for image formation onto a wide and long recording medium and a processing head for ejecting a pre-treatment liquid / post-treatment liquid is illustrated. The inkjet printer is suitable for digital printing and dyeing of images such as text and patterns on a recording medium composed of fabrics such as textiles and woven fabrics by inkjet printing. Of course, the image forming device of the present disclosure can also be used for printing various images on recording media such as paper sheets and resin sheets.

[0030] [Overall structure of an inkjet printer]

[0031] Figure 1 is a perspective view showing the overall structure of an inkjet printer 1 according to an embodiment of the present disclosure. Figure 2 yes Figure 1 Schematic cross-sectional view of line II-II. The inkjet printer 1 is a printer that prints an image on a wide and long workpiece W (recording medium, medium) by inkjet method. The inkjet printer 1 includes a device frame 10, and a workpiece conveying unit 20 and a carriage 3 assembled on the device frame 10. It should be noted that in this embodiment, the left-right direction is the main scanning direction S ( Figure 3 ), the direction from the rear to the front is the sub-scanning direction (the conveying direction F of the workpiece W).

[0032] The device frame 10 forms a framework for mounting various components of the inkjet printer 1. The workpiece conveying unit 20 is a mechanism for intermittently conveying (transporting) the workpiece W so that the workpiece W passes through a printing area where inkjet printing is performed in a conveying direction F from rear to front.

[0033] The carriage 3 carries a plurality of inkjet heads 4, a pre-processing head 5, a post-processing head 6, and a plurality of sub-tanks 7. The carriage 3 reciprocates in a main scanning direction S (horizontal direction) intersecting a conveying direction F of the workpiece W during the inkjet printing process.

[0034] The device frame 10 includes a central frame 111, a right frame 112, and a left frame 113. The central frame 111 forms a framework for mounting various components of the inkjet printer 1, and has a left-right width corresponding to the workpiece conveying unit 20. The right frame 112 and the left frame 113 are respectively erected on the right and left sides of the central frame 111. Between the right frame 112 and the left frame 113 is a printing area 12 for performing inkjet printing processing on the workpiece W.

[0035] The right frame 112 forms a maintenance area 13. The maintenance area 13 is an area where the carriage 3 is retracted when the inkjet printing process is not performed. In the maintenance area 13, assembly work and maintenance work are performed. The assembly work is a work of mounting a plurality of inkjet heads 4, a pre-processing head 5, a post-processing head 6, and a plurality of sub-tanks 7 on the carriage 3. The maintenance work is a work of replacing the plurality of inkjet heads 4, the pre-processing head 5, the post-processing head 6, and the sub-tanks 7 mounted on the carriage 3.

[0036] The left frame 113 forms a turn-back area 14 of the carriage 3. The turn-back area 14 is an area into which the carriage 3, which has performed main scanning of the printing area 12 from right to left in the inkjet printing process, temporarily enters when performing main scanning in the reverse direction.

[0037] A carriage guide 15 for reciprocating the carriage 3 in the left-right direction is assembled on the upper side of the device frame 10. The carriage guide 15 is a flat plate-shaped member that is long in the left-right direction and is arranged above the workpiece conveying unit 20. A timing belt 16 that is an endless belt is assembled to the carriage guide 15 so as to be able to circulate in the left-right direction (main scanning direction S).

[0038] The carriage guide 15 is provided with a pair of upper and lower guide rails 17 extending in parallel with the left-right direction to hold the carriage 3 in a state where the carriage 3 can reciprocate in the main scanning direction S. The carriage 3 is engaged with the guide rails 17. In addition, the carriage 3 is fixed to the timing belt 16. The carriage 3 is guided by the guide rails 17 as the timing belt 16 moves in the left or right direction, and moves in the left or right direction along the carriage guide 15.

[0039] Main reference Figure 2 . The workpiece conveying unit 20 includes a feed roller 21 for releasing the workpiece W before printing and a winding roller 22 for winding the workpiece W after printing. The feed roller 21 is arranged at the rear lower part of the device frame 10. The feed roller 21 is the winding body of the workpiece W before printing, that is, the winding shaft of the feed roll WA. The winding roller 22 is arranged at the front lower part of the device frame 10. The winding roller 22 is the winding body of the workpiece W after the inkjet printing process, that is, the winding shaft of the winding roll WB. A first motor M1 is attached to the winding roller 22. The first motor M1 drives the winding roller 22 to rotate around the axis to perform the winding action of the workpiece W.

[0040] The path between the delivery roller 21 and the winding roller 22 and passing through the printing area 12 is a conveying path for the workpiece W. In this conveying path, a first tension roller 23, a workpiece guide 24, a conveying roller 25 and a pinch roller 26, a return roller 27, and a second tension roller 28 are arranged in order from the upstream side. The first tension roller 23 applies a predetermined tension to the workpiece W on the upstream side of the conveying roller 25. The workpiece guide 24 changes the conveying direction of the workpiece W from the upper direction to the front direction, so that the workpiece W is carried into the printing area 12.

[0041] The conveying roller 25 is a roller that generates a conveying force for intermittently conveying the workpiece W in the printing area 12. The conveying roller 25 is driven by the second motor M2 to rotate about the axis. Thus, the conveying roller 25 intermittently conveys the workpiece W in the forward direction (predetermined conveying direction F) at a predetermined conveying pitch so that the workpiece W passes through the printing area 12 opposite to the carriage 3. The pinch roller 26 is arranged to face the conveying roller 25 from above. Thus, the pinch roller 26 and the conveying roller 25 form a conveying nip portion.

[0042] The folding roller 27 changes the conveying direction of the workpiece W passing through the printing area 12 from the front direction to the downward direction. Thus, the folding roller 27 guides the workpiece W after the inkjet printing process to the winding roller 22. The second tension roller 28 applies a predetermined tension to the workpiece W on the downstream side of the conveying roller 25. In the printing area 12, a platen 29 is arranged below the conveying path of the workpiece W.

[0043] The carriage 3 reciprocates in the printing area along a main scanning direction S (in the present embodiment, the left-right direction) intersecting (in the present embodiment, orthogonal to) the conveying direction F while being cantilever-supported by the guide rail 17. The carriage 3 includes a carriage frame 30, a plurality of inkjet heads 4, a pre-processing head 5, a post-processing head 6, and a plurality of sub-tanks 7 mounted on the carriage frame 30. The carriage frame 30 includes a head support frame 31 and a backrest frame 32.

[0044] The head support frame 31 is a horizontal plate for mounting a plurality of inkjet heads 4, a pre-processing head 5, and a post-processing head 6. The back frame 32 is a vertical plate extending upward from the rear end edge of the head support frame 31. The timing belt 16 is fixed to the back frame 32. The guide rail 17 is engaged with the back frame 32.

[0045] [Details of the carriage]

[0046] The carriage 3 will be further described. Figure 3 yes Figure 1 An enlarged perspective view of the carriage 3 is shown. Figure 3 , the conveying direction F (sub-scanning direction) of the workpiece W and the main scanning direction S which is the moving direction of the carriage 3 are shown. Figure 3 In the figure, there is shown an example in which a carriage 3 is equipped with a plurality of inkjet heads 4 (first liquid ejection heads) for ejecting ink for image formation onto a workpiece W, a pre-processing head 5 (second liquid ejection head) and a post-processing head 6 (second liquid ejection head) for ejecting a non-color developing processing liquid, and a plurality of sub-tanks 7 for supplying the ink and the processing liquid thereto.

[0047] The plurality of inkjet heads 4 include first to sixth inkjet heads 4A to 4F that eject six different colors of ink, respectively. As the ink, an ink (second ink) containing a water-based solvent and a pigment can be used. For example, the first inkjet head 4A ejects orange ink, the second inkjet head 4B ejects green ink, the third inkjet head 4C ejects yellow ink, the fourth inkjet head 4D ejects red ink, the fifth inkjet head 4E ejects blue ink, and the sixth inkjet head 4F ejects black ink. The inkjet heads 4A to 4F of each color are mounted on the head support frame 31 of the carriage 3 in a manner arranged in the main scanning direction S.

[0048] The pre-processing head 5 and the post-processing head 6 are mounted at positions different from the inkjet head 4 in the conveying direction F. The pre-processing head 5 is mounted on the upstream side of the inkjet head 4 in the conveying direction F. Figure 3 , an example is shown in which the pre-processing head 5 is mounted near the right end of the array of inkjet heads 4. Similarly, the post-processing head 6 is mounted on the downstream side relative to the inkjet head 4 in the conveying direction F. Figure 3 , an example is shown in which one post-processing head 6 is mounted on the right end of the array of inkjet heads 4. In other embodiments, multiple pre-processing heads 5 or multiple post-processing heads 6 may be mounted. That is, at least one pre-processing head 5 and at least one post-processing head 6 are mounted on the carriage 3, respectively.

[0049] The pre-treatment head 5 ejects a pre-treatment liquid for performing a predetermined pre-treatment on the workpiece W in order to fix the ink ejected from the inkjet head 4 to the workpiece W. The pre-treatment liquid is ejected from the pre-treatment head 5 to a position of the workpiece W where the ink has not yet been ejected from the inkjet head 4. The pre-treatment liquid is a non-color developing treatment liquid that does not develop color even if attached to the workpiece W. The pre-treatment liquid is ejected before the ink. As a result, the pre-treatment liquid exhibits functions such as improving the fixability of the ink to the workpiece W and the cohesion of the ink pigment (pigment). As such a pre-treatment liquid, a treatment liquid in which a binding resin is compounded in a solvent, or a treatment liquid in which a positively charged cationic resin is compounded in a solvent, etc. can be used.

[0050] The post-processing head 6 ejects a post-processing liquid for performing a prescribed post-processing on the workpiece W to which the ink is attached, in order to fix the ink ejected by the inkjet head 4 on the workpiece W. The post-processing liquid is ejected from the post-processing head 6 to the position of the workpiece W after the ink is ejected from the inkjet head 4. The post-processing liquid is also a non-color developing processing liquid that does not develop color even if attached to the workpiece W. The post-processing liquid is a processing liquid that exhibits the function of improving the fixability and firmness (resistance to friction and scraping) of the ink image printed on the workpiece W by the inkjet head 4. As such a post-processing liquid, a silicone-based processing liquid or the like can be used. It should be noted that the post-processing liquid and the pre-processing liquid are different processing liquids. Specifically, the components contained in the post-processing liquid and the pre-processing liquid are different.

[0051] Here, the non-color developing treatment liquid refers to a treatment liquid that cannot be recognized as a color developing by the naked eye when printed on the workpiece W alone. The colors here also include colors with a chroma of 0, such as black, white and gray. The non-color developing treatment liquid is basically a transparent liquid, but for example, when observing 1 liter of the treatment liquid in a liquid state, it sometimes does not look completely transparent, but slightly white. Such a color is very light, so when printed on the workpiece W alone, it cannot be recognized as a color developing by the naked eye. It should be noted that depending on the type of treatment liquid, when printed on the workpiece W alone, there may sometimes be changes in the gloss of the workpiece W, but such a state is not color developing.

[0052] A plurality of sub-tanks 7 are supported on the carriage 3 above the plurality of inkjet heads 4, the pre-processing head 5, and the post-processing head 6 via a holding frame (not shown). The plurality of sub-tanks 7 are provided corresponding to the plurality of inkjet heads 4, the pre-processing head 5, and the post-processing head 6, respectively. Ink or the processing liquid is supplied to each sub-tank 7 from an ink cartridge (not shown) or a main tank that contains ink and the processing liquid. Each sub-tank 7 supplies the supplied ink or the processing liquid to the inkjet head 4, the pre-processing head 5, or the post-processing head 6 corresponding to each sub-tank 7. Each sub-tank 7 is connected to the inkjet head 4, the pre-processing head 5, and the post-processing head 6 corresponding to each sub-tank 7 by a pipeline (not shown).

[0053] Specifically, the plurality of sub-tanks 7 include a first sub-tank 7A to a sixth sub-tank 7F arranged along the main scanning direction S on the rear side, a pre-processing sub-tank 75 , and a post-processing sub-tank 76 .

[0054] The first sub-tank 7A located on the leftmost side of the carriage 3 contains orange ink. The first sub-tank 7A supplies orange ink to the first inkjet head 4A. The orange ink is ejected from the first inkjet head 4A toward the workpiece W. Similarly, the second sub-tank 7B supplies green ink to the second inkjet head 4B. The other third sub-tanks 7C to the sixth sub-tank 7F also have the same structure and function as described above. The pre-processing sub-tank 75 supplies the pre-processing liquid to the pre-processing head 5, and the post-processing sub-tank 76 supplies the post-processing liquid to the post-processing head 6.

[0055] The above-mentioned multiple inkjet heads 4, pre-processing head 5 and post-processing head 6 are composed of multiple liquid ejection heads 8 that have completed the adjustment process, and the heads that eject three different liquids have common specifications. It should be noted that in the adjustment process, a predetermined test liquid is supplied to the liquid ejection head 8, and the voltage of the driving signal of the liquid ejection head 8 is adjusted in such a way that the ejection result of the test liquid ejected by the liquid ejection head 8 becomes a predetermined reference result. The details of the adjustment process will be described later.

[0056] The head support frame 31 is provided with a plurality of openings 31H for respectively mounting the plurality of inkjet heads 4, the pre-processing head 5, and the post-processing head 6. The liquid ejection head 8 is mounted on the head support frame 31 in a manner of being fitted into the openings 31H. After the liquid ejection head 8 is mounted on any of the openings 31H in the head support frame 31, a calibration process is further performed.

[0057] In the correction process, the voltage (hereinafter referred to as the adjustment voltage) of the drive signal of the liquid ejection head 8 adjusted in the adjustment process is corrected using the correction value associated with the liquid (hereinafter referred to as the ejection liquid) ejected by the liquid ejection head 8 mounted on the opening 31H. The ejection liquid ejected by the liquid ejection head 8 mounted on the opening 31H refers to the ink or the processing liquid supplied to the liquid ejection head 8 from the sub-tank 7 corresponding to the liquid ejection head 8.

[0058] For example, it is assumed that the liquid ejection head 8 after the adjustment process is mounted in the opening 31H for mounting the first inkjet head 4A. In this case, in the correction process, the adjustment voltage of the liquid ejection head 8 is corrected using the correction value associated with the orange ink ejected by the first inkjet head 4A. Thus, the first inkjet head 4A that can be driven by the drive signal based on the corrected voltage (hereinafter referred to as the correction voltage) in the correction process and ejects the orange ink is formed. Similarly, the second inkjet head 4B to the sixth inkjet head 4F are composed of the liquid ejection head 8.

[0059] In addition, it is assumed that the liquid ejection head 8 (second liquid ejection head) that has completed the adjustment process is mounted in the opening 31H for mounting the pre-processing head 5. In this case, in the correction process, the adjustment voltage (second adjustment voltage) of the liquid ejection head 8 is corrected using the correction value associated with the pre-processing liquid ejected by the pre-processing head 5. Thus, the pre-processing head 5 that can be driven by the drive signal based on the adjusted voltage after the correction process and ejects the pre-processing liquid is configured. Similarly, the post-processing head 6 is configured by the liquid ejection head 8.

[0060] That is, the liquid ejection head 8 is configured to eject a plurality of liquids such as inks of a plurality of colors, a pre-processing liquid, and a post-processing liquid that can be supplied after being mounted on the inkjet printer 1 .

[0061] As described above, the inkjet printer 1 of the present embodiment is an all-in-one printer in which three heads, namely, the inkjet head 4, the pre-processing head 5, and the post-processing head 6, are mounted on one carriage 3. According to the inkjet printer 1, for example, in the printing and dyeing process of inkjet printing on cloth in digital printing and dyeing, the pre-processing liquid ejection process and the post-processing liquid ejection process can be performed integrally. Therefore, the printing and dyeing process can be simplified and the printing and dyeing device can be made compact.

[0062] [Principle of ejection of liquid by the liquid ejection head]

[0063] Next, the principle of ejecting liquid by the liquid ejecting head 8 will be described. Figure 4 It is a diagram for explaining a driving signal of the liquid ejection head 8 . Figure 5A , Figure 5B and Figure 5C 2 is a diagram for explaining the principle of ejecting liquid from the liquid ejection head 8. Figure 5A , Figure 5B and Figure 5C As shown, the liquid ejection head 8 includes a piezoelectric element 81 such as a pressure element, a liquid pressurizing chamber 82 filled with liquid supplied from the sub-tank 7 via a pipe (not shown), and a nozzle 83 that ejects the liquid in the liquid pressurizing chamber 82 .

[0064] like Figure 4 As shown, the driving signal of the liquid ejection head 8 is a pulsed rectangular wave that periodically varies at a predetermined ejection cycle (ejection interval) T. The amplitude of the driving signal of the liquid ejection head 8 represents the voltage applied to the piezoelectric element 81 included in the liquid ejection head 8 .

[0065] When based on Figure 4 When the liquid ejection head 8 starts to be driven by the driving signal shown in FIG. 1 , the voltage "PV1" applied to the piezoelectric element 81 at the end of the previous ejection cycle T continues to be applied to the piezoelectric element 81 from time 0 to time t1. Figure 5A As shown, the deformed state of the piezoelectric element 81 is maintained for a certain period of time. As a result, the liquid in the liquid pressurizing chamber 82 is pressurized at a certain pressure, and the liquid in the liquid pressurizing chamber 82 is filled into the nozzle 83.

[0066] Next, from time t1 to time t2 ( Figure 4 ), the amplitude of the driving signal is 0, and the voltage applied to the piezoelectric element 81 stops. Figure 5B As shown, the deformed state of the piezoelectric element 81 is released, and the piezoelectric element 81 becomes parallel to the upper surface of the liquid pressurizing chamber 82. As a result, the liquid in the liquid pressurizing chamber 82 is decompressed, and part of the liquid in the nozzle 83 is filled into the liquid pressurizing chamber 82.

[0067] Then, from time t2 to time T ( Figure 4 ), the voltage "PV1" is applied to the piezoelectric element 81 again. Figure 5C As shown, the piezoelectric element 81 is deformed, and the liquid in the liquid pressurizing chamber 82 is pressurized, resulting in the liquid in the liquid pressurizing chamber 82 being ejected from the nozzle 83. In the following description, the total amount of liquid ejected from the nozzle 83 during one ejection cycle T is described as the ejection amount of the liquid.

[0068] Even with the same driving signal, the amount of liquid ejected from the liquid ejection head 8 varies depending on the physical properties of the liquid ejected from the liquid ejection head 8. The physical properties of the liquid include the contents of the liquid (dyes, pigments, colorants, resins, etc.), viscosity, and surface tension. In addition, the piezoelectric element 81, the liquid pressurizing chamber 82, and the nozzle 83 of the liquid ejection head 8 each have individual differences. Therefore, the amount of liquid ejected from the liquid ejection head 8 also varies depending on these individual differences.

[0069] Therefore, when the liquid ejecting head 8 is mounted on the head supporting frame 31 ( Figure 3 ), an adjustment process is performed to adjust the voltage of the driving signal of the liquid ejection head 8 to an adjustment voltage corresponding to the individual difference of the liquid ejection head 8. Then, the liquid ejection head 8 after the adjustment process is mounted on the head support frame 31 ( Figure 3 ), a correction process is performed to correct the voltage of the driving signal of the liquid ejection head 8 to a correction voltage corresponding to the ejection liquid ejected by the liquid ejection head 8. Thus, the inkjet head 4, the pre-processing head 5 or the post-processing head 6 composed of the liquid ejection head 8 can be driven in a manner of ejecting an appropriate amount of liquid by the driving signal of the correction voltage. The details of the adjustment process and the correction process will be described later.

[0070] [Electrical structure of inkjet printer]

[0071] Next, the electrical structure of the ink jet printer 1 according to the present embodiment will be described. Figure 6 1 is a block diagram showing the electrical structure of the inkjet printer 1 of the present embodiment. The inkjet printer 1 includes a control unit 90 that centrally controls the operation of each unit of the inkjet printer 1, a first motor M1 and a second motor M2, a carriage drive unit 3S, a plurality of liquid ejection heads 8 (inkjet head 4, pre-processing head 5, and post-processing head 6), an interface circuit 91 (hereinafter referred to as I / F 91), and an image memory 92.

[0072] The control unit 90 is composed of a CPU (Central Processing Unit), a ROM (Read Only Memory) storing a control program, a RAM (Random Access Memory) used as a work area of ​​the CPU, etc. In addition to the above-mentioned first motor M1 and second motor M2, the control unit 90 is also electrically connected to the carriage drive unit 3S, a plurality of liquid ejection heads 8 (a plurality of inkjet heads 4, a pre-processing head 5, and a post-processing head 6), an I / F 91, an image memory 92, etc.

[0073] The carriage driving unit 3S includes a motor (not shown) that causes the timing belt 16 to reciprocate the carriage 3 in the main scanning direction S, and the like.

[0074] In addition to the piezoelectric element 81, each of the plurality of liquid ejection heads 8 (the plurality of inkjet heads 4, the pre-processing head 5, and the post-processing head 6) further includes a memory 84 (storage unit). The memory 84 of each liquid ejection head 8 stores the adjustment voltage of each liquid ejection head 8 adjusted in the adjustment process in advance.

[0075] The image memory 92 temporarily stores printing image data supplied from an external device such as a personal computer.

[0076] I / F91 is an interface circuit for realizing data communication with an external device. I / F91, for example, generates a communication signal in accordance with the communication protocol of a network connecting the inkjet printer 1 and the external device. In addition, I / F91 converts the communication signal from the network side into data in a format that can be processed by the inkjet printer 1. A print instruction signal sent from a personal computer or the like is provided to the control unit 90 via I / F91. In addition, image data sent from a personal computer or the like is stored in the image memory 92 via I / F91.

[0077] The control unit 90 functions by having an acquisition unit 901 , a setting unit 902 , an image forming unit 903 , and a storage unit 904 when the CPU executes a control program stored in the ROM.

[0078] After the adjustment process is completed, the plurality of liquid ejecting heads 8 are respectively mounted on the head supporting frame 31 ( Figure 3 ) in the calibration process after the opening 31H is opened, the acquisition unit 901 acquires the adjustment voltage stored in the memory 84 provided in each liquid ejection head 8. Figure 3 ) The liquid ejection head 8 having the opening 31H is referred to as a mounting head.

[0079] The setting unit 902 corrects the adjustment voltage (first adjustment voltage) obtained by the acquisition unit 901 from the memory 84 (first storage unit) provided in the mounting head mounted in the opening 31H (first mounting unit) for mounting the inkjet head 4 (first liquid ejection head) by using a correction value associated with the ink ejected by the mounting head. The setting unit 902 sets the corrected voltage, i.e., the correction voltage, as the voltage of the drive signal of the mounting head.

[0080] Similarly, the setting unit 902 corrects the adjustment voltage (second adjustment voltage) obtained by the acquisition unit 901 from the memory 84 (second storage unit) provided in the mounting head mounted in the opening 31H (second mounting unit) for mounting the pre-processing head 5, using the correction value associated with the processing liquid ejected by the mounting head. The setting unit 902 sets the corrected voltage, i.e., the correction voltage, as the voltage of the drive signal of the mounting head.

[0081] In addition, the setting unit 902 corrects the adjustment voltage obtained by the obtaining unit 901 from the memory 84 of the mounting head mounted in the opening 31H for mounting the post-processing head 6, using a correction value associated with the processing liquid ejected by the mounting head. The setting unit 902 sets the corrected voltage, i.e., the correction voltage, as the voltage of the drive signal of the mounting head.

[0082] The image forming unit 903 supplies a predetermined liquid to each of the plurality of mounting heads (the plurality of inkjet heads 4, the pre-processing head 5, and the post-processing head 6), and drives each of the plurality of mounting heads using a drive signal of a correction voltage set by the setting unit 902. Thus, the image forming unit 903 forms an image on the workpiece W using the ejected liquid ejected from each of the plurality of mounting heads.

[0083] More specifically, the image forming unit 903 causes specified ink to be ejected from the inkjet head 4 using a driving signal of the correction voltage set by the setting unit 902, and on the other hand, causes pre-processing liquid and post-processing liquid to be ejected from the pre-processing head 5 and post-processing head 6 using a driving signal of the correction voltage set by the setting unit 902, thereby forming an image on the workpiece W.

[0084] The storage unit 904 stores in advance various threshold values, parameters, and the like that are referred to by the acquisition unit 901 , the setting unit 902 , and the image forming unit 903 .

[0085] Specifically, the storage unit 904 is provided on the head support frame 31 ( Figure 3 ) of each opening 31H ( Figure 3 ), the ejection liquid ejected by the liquid ejection head 8 mounted at the opening 31H at the position, and the correction value for correcting the adjustment voltage of the liquid ejection head 8 are stored in advance in association with each other.

[0086] For example, the storage unit 904 is formed from the head support frame 31 ( Figure 3 ) is the first opening 31H ( Figure 3 ), the orange ink ejected by the first inkjet head 4A of the opening 31H mounted at the position, and the correction value for correcting the adjustment voltage of the first inkjet head 4A are stored in association in advance.

[0087] It should be noted that the configuration of the control unit 90 is not limited to the above-mentioned scheme, and may be different from the above-mentioned scheme according to the configuration of the device and the program, etc. In other words, the functions of the acquisition unit 901 , the setting unit 902 , and the image forming unit 903 described above can be executed by the control unit 90 .

[0088] [Liquid ejection head drive signal setting method]

[0089] Next, the method for setting the driving signal of the liquid ejection head 8 is described. The method for setting the driving signal of the liquid ejection head 8 is a method for setting the driving signal of the liquid ejection head 8. The driving signal set by the driving signal setting method is used, for example, during liquid ejection recording. During liquid ejection recording, the liquid ejection head 8 ejects liquid toward the workpiece W in order to form an image on the workpiece W. Figure 7 : is a flowchart showing the flow of the drive signal setting method.

[0090] In the driving signal setting method, first, after manufacturing the liquid ejection head 8, the liquid ejection head 8 is mounted on the head support frame 31 ( Figure 3 ) has a plurality of openings 31H ( Figure 3 At any time before any opening 31H in the liquid ejection head 8 is opened, an adjustment process is performed on the liquid ejection head 8. The adjustment process is a process for adjusting (correcting) the voltage of the driving signal of the liquid ejection head 8 according to the individual difference of the liquid ejection head 8. The adjustment process includes Figure 7 Step S1 and step S2 are shown.

[0091] In step S1, the liquid pressurizing chamber 82 ( Figure 5A ) supplies a predetermined inspection liquid so that the liquid ejection head 8 ejects each ejection cycle T ( Figure 4 ) is adjusted in such a way that the ejection result of the inspection liquid becomes a predetermined reference result.

[0092] As the inspection liquid, an ink (first ink) containing a water-based solvent and a dye different from the ejection liquid (ink, pre-treatment liquid or post-treatment liquid) ejected by the liquid ejection head 8 can be used. As the solvent, for example, propylene glycol and a surfactant can be used. As the dye, a dye that does not easily react (for example, condense, etc.) with the treatment liquid (pre-treatment liquid or post-treatment liquid) ejected by the liquid ejection head 8 can be used. For example, as such a dye, Blue No. 1 (cyan) can be used. It should be noted that the viscosity of the inspection liquid can also be adjusted by adjusting the ratio of the solvent and water contained in the inspection liquid. In addition, a preservative can also be included in the inspection liquid.

[0093] Step S1 is automatically performed by the inspection device executing a pre-assembled control program after the operator places the liquid ejection head 8 on a specified mounting portion of the inspection device. However, the present invention is not limited thereto, and step S1 may also be semi-automatically performed by the operator operating the inspection device after the operator places the liquid ejection head 8 on a specified mounting portion of the inspection device. The details of step S1 will be described later.

[0094] In step S2, the voltage of the driving signal of the liquid ejection head 8 adjusted in step S1, i.e., the adjusted voltage, is stored in the memory 84 provided in the liquid ejection head 8. Step S2 is automatically performed by the inspection device used in step S1. However, it is not limited to this, and step S2 can also be performed manually by an operator using a special tool for writing data to the memory 84.

[0095] After the adjustment process is completed, step S3 (loading process) and a calibration process are performed. The calibration process is a process of calibrating the adjustment voltage of the liquid ejection head 8 adjusted in the adjustment process according to the liquid ejected by the liquid ejection head 8. The calibration process includes Figure 7 Steps S4 and S5 are shown.

[0096] In step S3, the head support frame 31 ( Figure 3 ) is mounted on any one of the plurality of openings 31H of the liquid ejection head 8 after the adjustment process. Step S3 can be performed manually by an operator or automatically using an operating robot or the like. Hereinafter, the liquid ejection head 8 mounted on any one of the openings 31H in step S3 and being the target of the calibration process is recorded as the target head.

[0097] In step S4 , the voltage of the drive signal of the target head adjusted in step S1 , that is, the adjustment voltage, is corrected using a correction value associated with the discharge liquid to be discharged from the target head.

[0098] Specifically, in step S4, the acquisition unit 901 ( Figure 6 ) obtains the adjustment voltage of the target head adjusted in step S1 from the memory 84 of the target head. The setting unit 902 ( Figure 6 ) uses the correction value associated with the ejection liquid ejected by the target head to correct the adjustment voltage acquired by the acquisition unit 901. As described above, the correction value associated with the ejection liquid ejected by the target head is pre-stored in the storage unit 904 in association with the position of the opening 31H on which the target head is mounted. The details of step S4 will be described later.

[0099] In step S5, the setting unit 902 ( Figure 6 ) The corrected voltage in step S4, i.e., the correction voltage, is set as the voltage of the driving signal of the liquid ejection head 8 during liquid ejection recording.

[0100] In the present drive signal setting method, the voltage of the drive signal of the liquid ejection head 8 is adjusted through an adjustment process so that the ejection result of the test liquid ejected by the liquid ejection head 8 becomes a predetermined reference result. In addition, through a correction process after the adjustment process, the voltage of the drive signal of the liquid ejection head 8 adjusted in the adjustment process, that is, the adjustment voltage, is further adjusted to a correction voltage corrected using a correction value associated with the ejection liquid ejected by the liquid ejection head 8. Therefore, according to the present drive signal setting method, the voltage of the drive signal of the liquid ejection head 8 mounted behind the one opening 31H can be adjusted to a voltage suitable for the individual difference of the liquid ejection head 8 and the liquid ejected by the liquid ejection head 8.

[0101] On the other hand, after the voltage of the driving signal of the liquid ejection head 8 is adjusted to a voltage corresponding to the individual difference of the liquid ejection head 8 and the liquid ejected by the liquid ejection head 8, the liquid ejection head 8 is mounted on the prescribed opening 31H. In this case, in order to appropriately supply the same type of liquid as the liquid used for the adjustment, it is necessary to perform a complicated operation such as accurately mounting the liquid ejection head 8 on the prescribed opening 31H.

[0102] However, according to the present drive signal setting method, after the liquid ejection head 8 is mounted on the opening 31H, the adjustment voltage of the liquid ejection head 8 is corrected to a correction voltage suitable for the liquid ejected by the liquid ejection head 8. Therefore, without performing the complicated operations described above, the liquid ejection head 8 after the adjustment process can be mounted on any opening 31H included in the inkjet printer 1, and the liquid ejected by the liquid ejection head 8 mounted on the opening 31H can be appropriately supplied.

[0103] Therefore, the image forming section 903 can form an image of appropriate density on the workpiece W using an appropriate amount of ejected liquid ejected from the inkjet head 4 , the pre-processing head 5 , and the post-processing head 6 constituted by the liquid ejecting head 8 .

[0104] In addition, the inspection liquid supplied to the liquid ejection head 8 in the adjustment process is ink containing a dye, and the liquid ejected from the inkjet head 4, the pre-processing head 5, and the post-processing head 6 formed by the liquid ejection head 8 that has undergone the adjustment process is ink containing a pigment or a processing liquid for fixing the ink containing the pigment to the workpiece W. Therefore, even if the inspection liquid supplied in the adjustment process remains in the liquid ejection head 8, the inspection liquid can be easily cleaned. As a result, the possibility of the ink or processing liquid ejected from the inkjet head 4, the pre-processing head 5, and the post-processing head 6 formed by the liquid ejection head 8 and agglomerating due to mixing with the remaining inspection liquid can be reduced.

[0105] In addition, the liquid ejection head 8 is provided with a memory 84, and the memory 84 stores the voltage of the driving signal for causing the liquid ejection head 8 to eject the inspection liquid in a manner that becomes a predetermined reference result. Therefore, after the liquid ejection head 8 that has completed the adjustment process is mounted on any opening 31H provided by the inkjet printer 1, the voltage of the driving signal of the liquid ejection head 8 can be adjusted to a voltage suitable for the liquid ejected by the liquid ejection head 8 in the calibration process. Therefore, the liquid ejection head 8 can be mass-produced as a common component that can be mounted on any mounting portion provided by a liquid ejection recording device such as the inkjet printer 1 used in the above-mentioned driving signal setting method.

[0106] It should be noted that the plurality of inkjet heads 4 , pre-processing head 5 , and post-processing head 6 included in the inkjet printer 1 are configured by repeatedly performing a calibration process on the liquid ejection head 8 after the adjustment process is completed and the liquid ejection head 8 is mounted on one opening 31H.

[0107] However, instead of this, the multiple inkjet heads 4, pre-processing heads 5 and post-processing heads 6 of the inkjet printer 1 can also be constructed in the following manner: first, the adjustment process is performed on the multiple liquid ejection heads 8 respectively, and then after the multiple adjustment processes are all completed, the multiple liquid ejection heads 8 that have completed the adjustment process are mounted on the multiple openings 31H, and then the multiple liquid ejection heads 8 are respectively subjected to the correction process.

[0108] That is, the manufacturer of the inkjet printer 1 purchases a plurality of liquid ejection heads 8 that have completed the adjustment process, and after mounting the plurality of liquid ejection heads 8 on the inkjet printer 1 to be manufactured, performs a calibration process on each of the plurality of liquid ejection heads 8, thereby enabling the plurality of liquid ejection heads 8 to be constructed as a plurality of inkjet heads 4, pre-processing heads 5, and post-processing heads 6 in the inkjet printer 1.

[0109] In addition, the identification information of the liquid ejecting head 8 may be stored in advance in the memory 84 of the liquid ejecting head 8. Accordingly, in step S2, the control unit 90 may store the voltage of the driving signal of the liquid ejecting head 8 adjusted in step S1, i.e., the adjusted voltage, in association with the identification information of the liquid ejecting head 8 in the storage unit 904 ( Figure 6 ), can also be stored in a memory that can use I / F91 ( Figure 6 ) is a storage unit of an external device for communication. Then, in step S4, the acquisition unit 901 ( Figure 6 ) can also be obtained from the storage unit 904 ( Figure 6 ) or a storage unit of the external device obtains the adjustment voltage of the object head associated with the identification information of the object head.

[0110] Alternatively, after step S2 and before step S3 , after cleaning the test liquid remaining in the liquid ejecting head 8 , the liquid ejecting head 8 may be filled with a predetermined ejecting liquid to be ejected from the liquid ejecting head 8 .

[0111] [Details of Step S1]

[0112] Next, step S1 ( Figure 7 ) is described in detail. In step S1, the voltage of the driving signal of the liquid ejection head 8 is adjusted in such a way that the ejection result of the test liquid ejected by the liquid ejection head 8 becomes a predetermined reference result. In this embodiment, the reference result is set to the ejection amount of the test liquid being a predetermined reference amount. In this case, specifically, in step S1, the following steps (1) to (4) are performed.

[0113] First, in step (1), the inspection liquid is supplied to the liquid ejecting head 8 (hereinafter referred to as the inspection target head) to be subjected to the adjustment step.

[0114] Next, in step (2), the inspection liquid is ejected toward the workpiece W by driving the inspection head with a driving signal having a predetermined waveform and voltage which is usually used for ejecting ink.

[0115] Next, in step (3), the density (OD (optical density)) of the image formed on the workpiece W by the inspection liquid ejected from the inspection head in step (2) is measured.

[0116] Then, in step (4), the concentration measured in step (3) is compared with the concentration of an image formed on the workpiece W using a predetermined reference amount of the inspection liquid (hereinafter referred to as the reference concentration), and steps (2) to (4) are performed by repeatedly increasing or decreasing the voltage of the drive signal used in step (2) until the concentration measured in step (3) is consistent with the reference concentration. The reference concentration can be predetermined based on an experimental value. The consistency between the concentration measured in step (3) and the reference concentration means that the concentration measured in step (3) is consistent with the reference concentration within a predetermined error range.

[0117] In step (4), when the concentration measured in step (3) matches the reference concentration, step S1 is terminated and step S2 is performed ( Figure 7 ). Thus, in step S2 ( Figure 7 ), the voltage of the drive signal used in the most recent step (2) when step S1 is finished is stored in the memory 84 as the adjustment voltage.

[0118] Therefore, in step S1 , it is possible to more accurately confirm that the discharge amount of the inspection liquid satisfies the reference amount based on the density of the image actually formed on the workpiece W by the inspection liquid, rather than numerical estimation.

[0119] It should be noted that the reference amount used in step (4) can be determined as the discharge amount of the test liquid when the liquid discharge head 8 is driven by a drive signal (hereinafter referred to as a standard drive signal) for causing the liquid discharge head 8 to discharge a predetermined target amount of a standard discharge liquid. The standard discharge liquid is, for example, black ink or other ink that is used in a standard manner in the inkjet printer 1. The target amount can be determined, for example, to an amount such that the user of the inkjet printer 1 does not feel uncomfortable with the density of the image formed on the workpiece W by causing the liquid discharge head 8 to discharge the target amount of the standard discharge liquid.

[0120] Figure 8 This is a chart used to determine the baseline amount. Figure 8 A broken line G10 shows the relationship between the voltage (horizontal axis) of the driving signal of the liquid ejecting head 8 and the ejection amount (vertical axis) of the standard ejection liquid when the liquid ejecting head 8 is driven by the driving signal of the voltage. Figure 8 A broken line G11 shows the relationship between the voltage of the driving signal of the liquid ejecting head 8 (horizontal axis) and the ejection amount of the test liquid (vertical axis) when the liquid ejecting head 8 is driven by the driving signal of the voltage. Figure 8 The shown broken lines G10 and G11 can be derived from experimental values.

[0121] For example, using Figure 8 The diagram shown can determine the driving signal with a voltage of "PV10" that causes the liquid ejection head 8 to eject a target amount "M0" (e.g., 18 pl) of standard ejection liquid as the standard driving signal. Furthermore, the ejection amount "M1" (e.g., 17 pl) of the test liquid when the liquid ejection head 8 is driven by the standard driving signal can be determined as the reference amount.

[0122] The density of the image formed when the inspection liquid of the reference amount "M1" is ejected onto the workpiece W is defined as "D1". In this case, an example of adjusting the voltage of the driving signal of the first liquid ejection head 8 and the second liquid ejection head 8 which are different from each other in step S1 is shown in FIG. Fig. 9 . Fig. 9 The horizontal axis represents the voltage of the driving signal used in step (2), and the vertical axis represents the concentration measured in step (3).

[0123] Fig. 9The broken line G21 shows an example in which, in step S1, when the inspection target head is the first liquid ejection head 8, the voltage of the drive signal used in step (2) is increased from "PV20" to "PV21", and as a result, the concentration measured in step (3) is consistent with the reference concentration "D1", and step S1 is terminated. In this case, in step S2, the voltage "PV21" is stored in the memory 84 of the first liquid ejection head 8.

[0124] Fig. 9 The broken line G22 shows an example in which, in step S1, when the inspection target head is a second liquid ejection head 8 different from the first liquid ejection head 8, the voltage of the drive signal used in step (2) is increased from "PV20" to "PV22", and as a result, the concentration measured in step (3) is consistent with the reference concentration "D1", and step S1 is terminated. In this case, in step S2, the voltage "PV22" is stored in the memory 84 of the second liquid ejection head 8.

[0125] As described above, the reference amount is determined as the discharge amount of the test liquid (e.g., 17 pl) when the liquid discharge head 8 is driven by a standard driving signal for causing the liquid discharge head 8 to discharge a specified target amount (e.g., 18 pl) of a standard discharge liquid (e.g., standard ink, black ink).

[0126] In this case, if a driving signal whose voltage is adjusted so that the discharge amount of the test liquid discharged from the liquid discharge head 8 becomes a reference amount (e.g., 17 pl) is used in step S1, the liquid discharge head 8 can discharge the target amount of the standard discharge liquid. In other words, in step S1, the voltage of the driving signal can be adjusted so that the discharge amount of the standard discharge liquid (e.g., standard ink, black ink) discharged from the liquid discharge head 8 becomes the target amount (e.g., 18 pl).

[0127] It should be noted that in this embodiment, the reference result used in step S1 is set to the discharge amount of the test liquid as a predetermined reference amount. However, the reference result is not limited to the discharge amount of the test liquid, and may be determined using, for example, a discharge result such as the discharge speed of the test liquid discharged by the liquid discharge head 8. Accordingly, the contents of step (3) and step (4) may be appropriately changed.

[0128] [Details of Step S4]

[0129] Next, in step S4 ( Figure 7 ) in setting unit 902 ( Figure 6 ) The method of adjusting the voltage of the calibration target head is explained in detail.

[0130] In step S4 , the setting unit 902 performs the following processes (1) to (3).

[0131] First, in processing (1), the setting unit 902 obtains from the storage unit 904 a correction value that is pre-associated with the position (e.g., right 1 rear 1) at which the object head (e.g., pre-processing head 5) is mounted and the liquid ejecting head 8 through the opening 31H mounted at the position, i.e., the ejecting liquid (e.g., pre-processing liquid) ejected by the object head (e.g., pre-processing head 5).

[0132] The correction value acquired in the process (1) is determined as follows. Fig.10 is a graph used to determine correction values. Fig.10 A broken line G30 represents the relationship between the voltage (horizontal axis) of the driving signal of the liquid ejection head 8 and the ejection amount (vertical axis) of the standard ejection liquid (for example, black ink) when the liquid ejection head 8 is driven by the driving signal of the voltage. Fig.10 A broken line G31 shows the relationship between the voltage (horizontal axis) of the driving signal of the liquid ejecting head 8 and the ejection amount (vertical axis) of the ejecting liquid (for example, pre-processing liquid) ejected by the target head when the liquid ejecting head 8 is driven by the driving signal of the voltage. Fig.10 The shown broken lines G30 , G31 can be derived from experimental values.

[0133] Specifically, use Fig.10 The graph shown determines as a correction value the difference “OFV (=PV31-PV30)” (e.g., -2.1 V) between the voltage “PV31” (e.g., 22.0 V) of the driving signal required for causing the liquid ejection head 8 to eject the target amount “M0” (e.g., 18 pl) of the ejection liquid and the voltage “PV30” (e.g., 24.1 V) of the driving signal required for causing the liquid ejection head 8 to eject the standard ejection liquid of the target amount “M0”.

[0134] After process (1), in process (2), the setting unit 902 adds the correction value acquired in process (1) to the voltage acquired from the memory 84 of the target head by the acquisition unit 901 in step S4, thereby performing correction to offset the voltage acquired from the memory 84 of the target head.

[0135] Then, in process (3), the setting unit 902 stores the corrected voltage in process (2) in association with the identification information of the target head in the storage unit 904. Thus, the setting unit 902 sets the corrected voltage in process (2) as the voltage of the drive signal of the target head during liquid ejection recording.

[0136] It should be noted that the image forming unit 903 ( Figure 6) During liquid ejection recording, a voltage associated with the identification information of each of the inkjet head 4, pre-processing head 5 and post-processing head 6 of the object driven to form an image on the workpiece W is obtained, and the inkjet head 4, pre-processing head 5 and post-processing head 6 of the object are driven respectively by the driving signal of the obtained voltage.

[0137] Therefore, in step S1, when the voltage of the driving signal of the object head is adjusted in such a manner that the discharge amount of a standard discharge liquid (e.g., standard ink, black ink) discharged by the object head becomes a predetermined target amount (e.g., 18 pl), in step S4, the voltage offset of the driving signal of the object head adjusted in step S1 is the difference between the voltage of the driving signal required for the object head to discharge the discharge liquid (e.g., pretreatment liquid) of the target amount (e.g., 18 pl) and the voltage of the driving signal is adjusted.

[0138] As a result, the voltage of the drive signal after the shift becomes the voltage of the drive signal required for the target head to eject the ejection liquid (e.g., pre-treatment liquid) of the target amount (e.g., 18 pl). Therefore, the voltage of the drive signal of the target head during liquid ejection recording can be adjusted to the voltage of the drive signal required for the liquid ejection head 8 to eject the ejection liquid (e.g., pre-treatment liquid) of the specified target amount (e.g., 18 pl).

[0139] In addition, when the ejection liquid ejected by the object head is a pre-treatment liquid and a post-treatment liquid, since they are non-color developing, it is impossible to use the concentration of the image actually formed by the ejection liquid to adjust the drive signal when the ejection liquid is ejected as in step S1. However, in a laboratory, etc., it is possible to measure the voltage of the drive signal when the liquid ejection head 8 ejects the same target amount of standard ejection liquid, pre-treatment liquid and post-treatment liquid, and record the relationship between the measured values. Therefore, in this embodiment, as described above, the voltage of the drive signal when the object head ejects the ejection liquid is corrected based on the relationship with the voltage of the drive signal when the standard ejection liquid is ejected.

[0140] It should be noted that the present correction method is not limited to non-color developing treatment liquids, and can also be used when the target head ejects ink (e.g., yellow ink, hereinafter referred to as target ink) different from the standard ink (e.g., black ink). That is, the voltage of the driving signal when the liquid ejection head 8 ejects the same target amount of the standard ejection liquid and the target ink can be measured, and based on the relationship between the measured values, the voltage of the driving signal when ejecting the target ink can be corrected based on the relationship with the voltage of the driving signal when ejecting the standard ejection liquid.

[0141] On the other hand, it is assumed that the ejection liquid ejected by the target head is a standard ejection liquid (for example, black ink). In this case, the difference between the voltage of the drive signal required to eject the target amount of the ejection liquid from the target head and the voltage of the drive signal required to eject the target amount of the standard ejection liquid from the target head is 0. Therefore, in the case where the ejection liquid ejected by the target head is the standard ejection liquid, the correction value for correcting the voltage of the drive signal of the target head is 0. Therefore, in the case where the ejection liquid ejected by the target head is the standard ejection liquid, in step S4, the correction of the adjustment voltage is omitted, which can shorten the time required for the correction process.

[0142] It should be noted that the correction value obtained in process (1) and used in process (2) is not limited to the difference between the voltage of the driving signal required to make the liquid ejection head 8 eject the target amount of ejection liquid ejected by the object head as described above and the voltage of the driving signal required to make the liquid ejection head 8 eject the target amount of standard ejection liquid.

[0143] For example, the liquid ejection head 8 may be caused to eject a target amount (eg, M0 ( Fig.10 ), 18pl) of the required drive signal voltage (for example, PV31 ( Fig.10 ), 22.0V) relative to the voltage of the drive signal required to cause the liquid ejection head 8 to eject the target amount of standard ejection liquid (for example, PV30 ( Fig.10 ), 24.1V) ratio (for example, PV31 / PV30, 22.0 / 24.1) is determined as the correction value acquired in process (1) and used in process (2). In this case, in process (2), the voltage acquired from the memory 84 of the target head by the acquisition unit 901 can be corrected by multiplying the voltage acquired from the memory 84 of the target head by the correction value acquired in process (1).

[0144] Alternatively, the correction value obtained in process (1) and used in process (2) may be the difference between the voltage of a driving signal required to cause the liquid ejection head 8 to eject a specified amount of ejection liquid different from the target amount, and the voltage of a driving signal required to cause the liquid ejection head 8 to eject a target amount of standard ejection liquid.

[0145] This correction value is determined as follows. Fig.11 is a graph used to determine correction values. Fig.11 A broken line G40 represents the relationship between the voltage (horizontal axis) of the driving signal of the liquid ejection head 8 and the ejection amount (vertical axis) of the standard ejection liquid (for example, black ink) when the liquid ejection head 8 is driven by the driving signal of the voltage. Fig.11A broken line G41 shows the relationship between the voltage (horizontal axis) of the driving signal of the liquid ejecting head 8 and the ejection amount (vertical axis) of the ejecting liquid (for example, post-processing liquid) ejected by the target head when the liquid ejecting head 8 is driven by the driving signal of the voltage. Fig.11 The shown broken lines G40, G41 can be derived from experimental values.

[0146] Specifically, use Fig.11 The graph shown determines as a correction value the difference “OFV (=PV41-PV40)” (e.g., +2.2V) between the voltage “PV41” (e.g., 26.3V) of the driving signal required to cause the liquid ejection head 8 to eject a specified amount (e.g., 9pl) of ejection liquid different from the target amount “M0” (e.g., 18pl) and the voltage “PV40” (e.g., 24.1V) of the driving signal required to cause the liquid ejection head 8 to eject a standard ejection liquid of the target amount “M0”.

[0147] In this case, in step S1 ( Figure 7 ), in the case where the voltage of the drive signal of the target head is adjusted so that the discharge amount of the standard discharge liquid discharged by the target head becomes a predetermined target amount (for example, 18 pl), in step S4 ( Figure 7 ), the voltage offset of the drive signal of the target head adjusted in step S1 is the difference between the voltage of the drive signal required for the target head to eject a specified amount (e.g., 9 pl) of ejection liquid (e.g., post-processing liquid) different from the target amount and the voltage.

[0148] As a result, the voltage of the drive signal after the shift becomes the voltage of the drive signal required to make the target head eject a predetermined amount (e.g., 9 pl) of ejection liquid (e.g., post-processing liquid) different from the target amount. Therefore, the voltage of the drive signal of the target head during liquid ejection recording can be adjusted to the voltage of the drive signal required to make the liquid ejection head 8 eject the predetermined amount (e.g., 9 pl) of ejection liquid (e.g., post-processing liquid) different from the target amount.

[0149] In addition, in step S5 ( Figure 7 ), the setting unit 902 ( Figure 6 ) In addition to setting the driving voltage of the target head, a waveform corresponding to the physical properties of the ejected liquid ejected by the target head can also be set as the waveform of the driving signal of the target head.

[0150] This structure can be realized, for example, as follows. The waveform corresponding to the physical properties of the ejection liquid ejected by the liquid ejection head 8 can be predetermined based on the experimental results of supplying a plurality of liquids with different physical properties (content, viscosity, surface tension, etc.) to the liquid ejection head 8 and ejecting them. For example, the waveform of the driving signal of the liquid ejection head 8 can be determined based on the application time of the voltage to the piezoelectric element 81 and the cut-off time of the voltage to the piezoelectric element 81 in one ejection cycle T of the driving signal of the liquid ejection head 8, and the number of times the voltage is repeatedly applied and cut off to the piezoelectric element 81.

[0151] The storage unit 904 not only stores in advance the Figure 3 ) of each opening 31H ( Figure 3 ) is associated with the ejection liquid ejected from the liquid ejection head 8 mounted at the opening 31H at that position and is used to correct the voltage value of the driving signal of the liquid ejection head 8, and a waveform corresponding to the predetermined physical properties of the ejection liquid is pre-stored.

[0152] Accordingly, the setting unit 902 performs step S5 ( Figure 7 ), a waveform previously associated with the position of the opening 31H on which the target head is mounted and the ejection liquid ejected by the target head mounted at the opening 31H at the position is obtained from the storage unit 904.

[0153] The setting unit 902 associates the waveform acquired from the storage unit 904 with the identification information of the target head and stores it in the storage unit 904. Thus, the setting unit 902 sets the waveform acquired from the storage unit 904 as the waveform of the drive signal of the target head during liquid ejection recording.

[0154] It should be noted that the timing at which the setting unit 902 sets the waveform of the drive signal of the target head is not limited to step S5 ( Figure 7 ), or it can be step S3 ( Figure 7 ) and at any time after the object head is formed.

[0155] According to this configuration, the inkjet heads 4 , pre-processing heads 5 , and post-processing heads 6 can be made to eject an appropriate amount of liquid by using a driving signal having a waveform corresponding to the physical properties of the ejected liquid ejected from the inkjet heads 4 , pre-processing heads 5 , and post-processing heads 6 .

[0156] As mentioned above, the ink jet printer 1 according to one embodiment of the present disclosure has been described, but the present disclosure is not limited thereto, and for example, the following modified embodiments can be adopted.

[0157] A part or all of the control unit 90 of the inkjet printer 1 may be a personal computer or the like that sends printing image information to the inkjet printer 1. The inkjet printer 1 is not limited to a structure that can eject inks of multiple colors to the workpiece W, and may eject ink of a single color. The inkjet printer 1 may not have the pre-processing head 5 that ejects the pre-processing liquid, the post-processing head 6 that ejects the post-processing liquid, and components related thereto.

[0158] In the above-mentioned embodiment, the inkjet head 4, the pre-processing head 5 and the post-processing head 6 are composed of the liquid ejection head 8 after the adjustment process, and they have the same specifications. However, it is also possible to make only the inkjet head 4 composed of the liquid ejection head 8 after the adjustment process, and make the specifications of the inkjet head 4 different from those of the pre-processing head 5 and the post-processing head 6.

[0159] A plurality of structures disclosed in the above-mentioned embodiments can constitute one invention by being combined with each other.

[0160] Description of reference numerals:

[0161] 1: Inkjet printer (liquid ejection recording device, image forming device)

[0162] 4: Inkjet head (first liquid ejection head)

[0163] 5: Pre-treatment head (second liquid ejection head)

[0164] 6: Post-processing head (second liquid ejection head)

[0165] 8: Liquid ejection head

[0166] 31H: ​​Opening (mounting part, first mounting part, second mounting part)

[0167] 81: Piezoelectric element

[0168] 82: Liquid Pressurization Chamber

[0169] 83: Nozzle

[0170] 84: Memory (storage unit)

[0171] 901: Acquisition

[0172] 902: Setting Department

[0173] 903: Image forming unit

[0174] 904: Storage unit.

Claims

1. A method for setting a driving signal, wherein: The driving signal setting method comprises: An adjustment step of adjusting a voltage of a driving signal of a liquid ejection head capable of ejecting a liquid to an adjustment voltage so that an ejection result of a predetermined test liquid ejected by the liquid ejection head becomes a predetermined reference result; a mounting step of mounting the liquid ejection head after the adjustment step on a liquid ejection recording device; and The correction step is to correct the adjustment voltage to a correction voltage by using a correction value associated with the discharge liquid discharged by the liquid discharge head after the mounting step.

2. The driving signal setting method according to claim 1, wherein: The driving signal setting method further includes a storing step of storing the adjustment voltage in a storage unit provided in the liquid ejection head.

3. A method for setting a driving signal, wherein: The driving signal setting method comprises: a mounting step of mounting a liquid ejection head on a liquid ejection recording device, the liquid ejection head being capable of ejecting liquid, and wherein a voltage of a driving signal is adjusted to an adjustment voltage in such a manner that an ejection result of ejecting a predetermined inspection liquid by the liquid ejection head becomes a predetermined reference result; and The correction step is to correct the adjustment voltage to a correction voltage by using a correction value associated with the discharge liquid discharged by the liquid discharge head after the mounting step.

4. The driving signal setting method according to claim 3, wherein: The driving signal setting method further includes a storing step of storing the adjustment voltage in a storage unit provided in the liquid ejection head.

5. The driving signal setting method according to any one of claims 1 to 4, wherein: The liquid ejection head comprises a first liquid ejection head and a second liquid ejection head, The ejection liquid includes ink and a non-color developing treatment liquid, In a state of being mounted on the liquid ejection recording apparatus, the first liquid ejection head can eject the ink, and the second liquid ejection head can eject the non-color developing processing liquid.

6. The driving signal setting method according to claim 5, wherein: The non-color developing treatment liquid is a pre-treatment liquid ejected before the ink.

7. The driving signal setting method according to any one of claims 1 to 4, wherein: The inspection liquid is a liquid different from the ejection liquid.

8. The driving signal setting method according to claim 7, wherein: The inspection liquid is a first ink containing a dye.

9. The driving signal setting method according to claim 7, wherein: The ejection liquid is a second ink containing a pigment or a treatment liquid for fixing the second ink to a recording medium.

10. The driving signal setting method according to any one of claims 1 to 4, wherein: The drive signal setting method further includes, after the mounting step, a step of setting the waveform of the drive signal to a waveform corresponding to the physical properties of the ejection liquid.

11. The driving signal setting method according to claim 1, wherein: The reference result is that the discharge amount of the test liquid is a predetermined reference amount.

12. The driving signal setting method according to claim 11, wherein: In the adjustment process, When the density of an image formed when the liquid ejection head ejects the inspection liquid onto a medium using the driving signal matches the density of an image formed on the medium by the inspection liquid in the reference amount, the ejection result is set to be the reference result.

13. The driving signal setting method according to claim 11, wherein: In the adjustment process, the discharge amount of the test liquid when the liquid discharge head is driven by a standard drive signal for causing the liquid discharge head to discharge a predetermined target amount of standard discharge liquid is set as the reference amount; In the calibration process, The correction value is a difference between a voltage of the driving signal required to cause the liquid ejection head to eject the target amount of the ejection liquid and a voltage of the driving signal required to cause the liquid ejection head to eject the target amount of the standard ejection liquid.

14. The driving signal setting method according to claim 3, wherein: The reference result is that the discharge amount of the test liquid is a predetermined reference amount.

15. The driving signal setting method according to claim 14, wherein: The adjustment voltage is the voltage of the driving signal adjusted so that when the concentration of the image formed when the liquid ejection head ejects the inspection liquid onto the medium using the driving signal is consistent with the concentration of the image formed on the medium by the reference amount of the inspection liquid, the ejection result becomes the reference result.

16. The driving signal setting method according to claim 14, wherein: The adjustment voltage is a voltage of the driving signal adjusted so that the discharge amount of the test liquid becomes the reference amount when the liquid discharge head is driven by a standard driving signal for causing the liquid discharge head to discharge a predetermined target amount of standard discharge liquid. In the calibration process, The correction value associated with the ejected liquid is set as a difference between a voltage of the drive signal required to cause the liquid ejection head to eject the target amount of the ejected liquid and a voltage of the drive signal required to cause the liquid ejection head to eject the target amount of the standard ejected liquid.

17. The driving signal setting method according to claim 13 or 16, wherein: The spray liquid is the standard spray liquid.

18. A liquid ejection head capable of ejecting liquid, wherein: The liquid ejection head includes a storage unit storing an adjustment voltage of a drive signal for causing the liquid ejection head to eject a predetermined test liquid so as to obtain a predetermined reference result.

19. An image forming apparatus, wherein: The image forming device comprises: a liquid ejection head capable of ejecting liquid, wherein the voltage of a driving signal is adjusted to an adjustment voltage so that an ejection result of a predetermined test liquid ejected by the liquid ejection head becomes a predetermined reference result; A carrying portion, which is used to carry the liquid ejection head; a correction section that corrects the adjustment voltage to a correction voltage using a correction value associated with a discharge liquid discharged from the liquid discharge head with respect to a drive signal of the liquid discharge head mounted on the mounting section; and The image forming section drives the liquid ejection head with the correction voltage to thereby form an image on a recording medium using the ejection liquid ejected from the liquid ejection head.

20. The image forming apparatus according to claim 19, wherein: The image forming apparatus further includes a storage unit storing the adjustment voltage. The correction unit obtains the adjustment voltage from the storage unit.

21. The image forming apparatus according to claim 20, wherein: The storage portion is provided in the liquid ejection head.

22. The image forming apparatus according to claim 19, wherein: The correction section acquires the adjustment voltage from a storage section provided outside the image forming apparatus and storing the adjustment voltage.

23. An image forming apparatus, wherein: The image forming device comprises: A liquid ejection head capable of ejecting liquid and comprising a first liquid ejection head and a second liquid ejection head, wherein the liquid ejection head has a storage unit storing an adjustment voltage, wherein the adjustment voltage is a voltage of a drive signal for causing the liquid ejection head to eject a predetermined inspection liquid in a manner that results in a predetermined reference result; A first carrying portion, which is used to carry the first liquid ejection head; as well as a second carrying portion for carrying the second liquid ejecting head; The adjustment voltage is a voltage that is a voltage of the drive signal when the density of an image formed on the medium by the test liquid ejected from the liquid ejection head to the medium matches the density of an image formed on the medium by the test liquid ejected from the liquid ejection head to the medium, when the test liquid ejected from the liquid ejection head to the medium is set as a reference density. The image forming device comprises: a correction section that corrects a second adjustment voltage stored in a second storage section provided in the second liquid ejecting head using a correction value associated with the processing liquid ejected by the second liquid ejecting head after the second liquid ejecting head is mounted on the second mounting section; as well as The image forming unit causes the first liquid ejection head to eject the ink by the driving signal of the first adjustment voltage stored in the first storage unit of the first liquid ejection head after the second liquid ejection head is mounted on the second mounting unit and the first liquid ejection head is mounted on the first mounting unit, and causes the second liquid ejection head to eject the processing liquid by the driving signal of the second adjustment voltage corrected by the correction unit, thereby forming an image on a recording medium. The correction value is a difference between a voltage of the drive signal required to cause the second liquid ejection head to eject the target amount of the treatment liquid and a voltage of the drive signal required to cause the second liquid ejection head to eject the target amount of the ink.

Images