JP7491749B2 - Inkjet printer - Google Patents

Description

The present invention relates to an inkjet printer.

Conventionally, inkjet printers have been known that include a pressure chamber in which ink is stored, a vibration plate that defines part of the pressure chamber, an actuator connected to the vibration plate, a nozzle that communicates with the pressure chamber, and a control device that drives the actuator by supplying a drive signal to the actuator.

In such inkjet printers, printing is performed on a recording medium by unidirectional printing or bidirectional printing. In an inkjet printer that performs bidirectional printing, when ink is ejected so that the ink lands at the same position on the recording medium in printing in the forward direction (hereinafter referred to as forward printing) and printing in the backward direction (hereinafter referred to as backward printing), the ink landing position may be shifted. Therefore, the shift in the ink landing position in the main scanning direction in forward printing and backward printing is corrected. For example, Patent Document 1 discloses a bidirectional adjustment pattern that has multiple pairs of vertical lines, each of which is made up of a vertical line printed in the forward direction and a vertical line printed in the backward direction. The vertical line pairs described in Patent Document 1 are printed by intentionally shifting the ink landing position by a predetermined correction value in the forward direction and the backward direction. The correction value is different for each pair of vertical lines, and the correction value of the vertical line pair with the least deviation in the printed bidirectional adjustment pattern is the correction value to be input. By printing such a bidirectional adjustment pattern, it is possible to check the deviation in the ink landing position between forward and reverse printing in bidirectional printing.

JP 2001-38963 A

However, even when bidirectional printing is performed using the correction values obtained by printing a bidirectional adjustment pattern, under certain conditions, the ink landing position may be slightly misaligned between forward and reverse printing. In other words, even if correction values are used, a problem may occur in which the quality of the printed matter is slightly degraded when an image is printed on a recording medium by bidirectional printing.

The present invention has been made in consideration of these points, and aims to provide an inkjet printer that can more accurately correct the deviation in the ink landing position during forward and reverse printing.

The inventor of the present application noticed that when ink is ejected simultaneously from multiple nozzles using a drive signal including a drive pulse having a relatively high drive voltage (e.g., 25V to 35V), the amount of change in the volume of the first pressure chamber communicating with one nozzle becomes smaller than the amount of change in the volume of the second pressure chamber communicating with another nozzle adjacent to the one nozzle. In other words, the inventor discovered that a phenomenon may occur in which the amount of ink ejected from one nozzle becomes smaller and the ejection speed becomes slower compared to other nozzles. This is thought to be due to the actuator that changes the volume of the second pressure chamber expanding, causing the case having the first pressure chamber and the second pressure chamber to expand. As a result of extensive research, the inventor discovered that in order to reduce the effect of the actuator that changes the volume of one pressure chamber on the change in the volume of the other pressure chamber, by not ejecting ink from the nozzle adjacent to the nozzle that ejects ink, it is possible to eject the same amount of ink from multiple nozzles at the same ejection speed. This makes it possible to more accurately correct the deviation in the ink landing position between forward and backward printing.

The inkjet printer according to the present invention includes an ink head that ejects ink onto a recording medium, a carriage that moves the ink head in a main scanning direction, a moving device that moves the recording medium in a sub-scanning direction perpendicular to the main scanning direction, and a control device that controls the ink head, the carriage, and the moving device. The ink head includes a case having a plurality of pressure chambers in which ink is stored, a plurality of vibration plates provided in the case that define a portion of each of the pressure chambers, a plurality of actuators connected to each of the vibration plates and that deform when an electric signal is supplied, and a plurality of nozzles formed in the case that are connected to each of the pressure chambers and aligned in the sub-scanning direction. the control device comprises: a drive signal generating unit that generates a drive signal including one or more drive pulses having a drive voltage of 25V to 35V for each drive cycle; a drive signal supplying unit that supplies a part or all of the drive signal generated by the drive signal generating unit to each actuator to eject ink from the nozzles; an image printing unit that prints an image based on image data on the recording medium by the forward direction printing and the backward direction printing when printing in which ink is ejected from the nozzles onto the recording medium while moving the ink head in a forward direction that is a direction from one side to the other of the main scanning direction is defined as forward direction printing, and printing in which ink is ejected from the nozzles onto the recording medium while moving the ink head in a backward direction that is a direction from the other side to one side of the main scanning direction is defined as backward direction printing; and a test pattern printing unit that prints a plurality of test patterns arranged in the main scanning direction by the forward direction printing and the backward direction printing, each of which has a correction value set to correct a deviation in the ink landing position between the forward direction printing and the backward direction printing, on the recording medium by the forward direction printing and the backward direction printing. In the forward direction printing and the backward direction printing, ink is ejected from some of the plurality of nozzles, and a second nozzle adjacent to a first nozzle that ejects ink among the plurality of nozzles is configured not to eject ink.

According to the inkjet printer of the present invention, when printing a test pattern on a recording medium by forward printing and backward printing, the second nozzle adjacent to the first nozzle that ejects ink is set not to eject ink. This makes it possible to make the deformation amount of the case deformed by each actuator that changes the volume of the pressure chamber of the multiple first nozzles that eject ink simultaneously approximately the same. In other words, since the deformation amount of the multiple actuators is the same, the volume change amount of each pressure chamber is also the same, and the same amount of ink can be ejected from the multiple first nozzles at the same ejection speed. This makes it possible to print the test pattern on the recording medium more accurately. As a result, bidirectional printing can be performed using more appropriate correction values, and the quality of the image printed on the recording medium by bidirectional printing can be improved.

The present invention provides an inkjet printer that can more accurately correct the misalignment of the ink landing position during forward and backward printing. In addition, when actually printing an image, the frequency with which ink is ejected simultaneously from multiple adjacent nozzles is low, so the characteristics are close to those of a case in which ink is not ejected from nozzles adjacent to a nozzle that ejects ink (i.e., when adjacent nozzles are thinned out).

FIG. 1 is a front view of a printer according to an embodiment. FIG. 2 is a bottom view of a carriage according to an embodiment. 1 is a cross-sectional view of a portion of an ink head according to an embodiment. 1 is a cross-sectional view of a portion of an ink head according to an embodiment. 1 is a block diagram showing a configuration of a printer according to an embodiment; 11A and 11B are schematic diagrams illustrating an overview of a bidirectional adjustment pattern. 11 is a cross-sectional view of a portion of an ink head when ink is ejected from a conventional printer. 4 is a cross-sectional view of a portion of the ink head when ink is ejected from the printer according to the embodiment. FIG.

Below, an embodiment of an inkjet printer (hereinafter referred to as printer) according to the present invention will be described with reference to the drawings. The embodiment described here is, of course, not intended to limit the present invention in any particular way. In addition, the same reference numerals are used for components and parts that perform the same function, and duplicate descriptions will be omitted or simplified.

1 is a front view of a printer 10 according to an embodiment. FIG. 2 is a bottom view of a carriage 25, which will be described later. In the following description, when the printer 10 is viewed from the front, the side away from the printer 10 is the front, and the side approaching the printer 10 is the rear. The symbols F, Rr, L, R, U, and D in the drawings represent the front, rear, left, right, top, and bottom, respectively. Also, the symbol Y in the drawings indicates the main scanning direction, the symbol X indicates the sub-scanning direction X perpendicular to the main scanning direction Y (for example, perpendicular in a plan view), and the symbol Z indicates the up-down direction. The main scanning direction Y corresponds to the left-right direction, and the sub-scanning direction X corresponds to the front-rear direction. Also, the rear corresponds to the upstream side of the sub-scanning direction X, and the front corresponds to the downstream side of the sub-scanning direction X. However, these are merely directions for convenience of explanation, and do not limit the installation mode of the printer 10.

As shown in FIG. 1, the printer 10 prints an image on the recording medium 5 by sequentially moving the rolled recording medium 5 forward and ejecting ink from ink heads 40A-40D (see FIG. 2) mounted on a carriage 25 that moves in the main scanning direction Y.

The recording medium 5 is an object on which an image is printed. There are no particular limitations on the recording medium 5. For example, the recording medium 5 may be paper such as plain paper or inkjet printing paper, a transparent sheet made of resin or glass, or a sheet made of metal or rubber.

As shown in FIG. 1, the printer 10 includes a printer body 10a, legs 11 that support the printer body 10a, and a control device 100. The printer body 10a extends in the main scanning direction Y. The printer body 10a includes a guide rail 21, a carriage 25 engaged with the guide rail 21, and a carriage movement mechanism 26. The guide rail 21 extends in the main scanning direction Y. The guide rail 21 guides the movement of the carriage 25 in the main scanning direction Y. The carriage movement mechanism 26 includes a pulley 23a provided on the right side of the guide rail 21, a pulley 23b provided on the left side of the guide rail 21, an endless belt 22 wound around the pulleys 23a and 23b, and a carriage motor 24 attached to the right pulley 23a. The belt 22 is fixed to the carriage 25. The carriage motor 24 is electrically connected to the control device 100. The carriage motor 24 is controlled by the control device 100. When the carriage motor 24 is driven, the pulley 23a rotates and the belt 22 runs. This causes the carriage 25 to move in the main scanning direction Y along the guide rail 21. In this way, the ink heads 40A to 40D also move in the main scanning direction Y as the carriage 25 moves in the main scanning direction Y. Note that, below, for convenience, the direction that coincides with the left side of the printer 10 may be referred to as the first main scanning direction Y1, and the direction that coincides with the right side of the printer 10 may be referred to as the second main scanning direction Y2.

As shown in FIG. 1, the platen 12 is disposed below the carriage 25. The platen 12 extends in the main scanning direction Y. The recording medium 5 is placed on the platen 12. Above the platen 12, a pinch roller 31 is provided to press down the recording medium 5 from above. The pinch roller 31 is disposed behind the carriage 25. The platen 12 is provided with a grit roller 32. The grit roller 32 is disposed below the pinch roller 31. The grit roller 32 is disposed in a position facing the pinch roller 31. The grit roller 32 is connected to a feed motor 33 (see FIG. 5). The grit roller 32 is formed to be rotatable by receiving the driving force of the feed motor 33. The feed motor 33 is electrically connected to the control device 100. The feed motor 33 is controlled by the control device 100. When the grit roller 32 rotates with the recording medium 5 sandwiched between the pinch roller 31 and the grit roller 32, the recording medium 5 is transported in the sub-scanning direction X. In this embodiment, the pinch roller 31, the grit roller 32, and the feed motor 33 are an example of a moving device 30 that moves the recording medium 5 in the sub-scanning direction X.

As shown in FIG. 2, the ink head 40 includes ink heads 40A to 40D. The ink heads 40A to 40D are held on the lower surface of the carriage 25. The ink heads 40A to 40D are formed in a shape in which the length in the sub-scanning direction X is longer than the length in the main scanning direction Y. The ink heads 40A to 40D are formed in the same shape and size. The ink heads 40A to 40D are arranged at the same position in the sub-scanning direction X. The ink heads 40A to 40D each have a plurality of nozzles 41 aligned in the sub-scanning direction X and a nozzle surface 42 in which the nozzles 41 are formed. The nozzles 41 eject ink onto the recording medium 5. The plurality of nozzles 41 are aligned in the sub-scanning direction X to form a nozzle row 43. The ink ejection density in the sub-scanning direction X is, for example, 180 dpi. The nozzle row 43 is divided into three partial nozzle rows 43A, 43B, and 43C aligned in the sub-scanning direction X. Hereinafter, the partial nozzle row indicated by the reference symbol 43A will be referred to as the first partial nozzle row 43A, the partial nozzle row indicated by the reference symbol 43B will be referred to as the second partial nozzle row 43B, and the partial nozzle row indicated by the reference symbol 43C will be referred to as the third partial nozzle row 43C. The first partial nozzle row 43A is an example of a downstream nozzle. The second partial nozzle row 43B is an example of a central nozzle. The third partial nozzle row 43C is an example of an upstream nozzle. The first partial nozzle row 43A is located downstream in the sub-scanning direction X. The second partial nozzle row 43B is located between the first partial nozzle row 43A and the third partial nozzle row 43C. The third partial nozzle row 43C is located upstream in the sub-scanning direction X. The number of nozzles 41 in the first partial nozzle row 43A, the number of nozzles 41 in the second partial nozzle row 43B, and the number of nozzles 41 in the third partial nozzle row 43C are the same (here, four). The nozzle row 43 is divided into three equal parts in the sub-scanning direction X by a first partial nozzle row 43A, a second partial nozzle row 43B, and a third partial nozzle row 43C. The nozzle row 43 is not limited to one row, and may be, for example, two or more rows. In FIG. 2, ink heads 40A to 40D are shown to have 12 nozzles, but in reality many more nozzles (for example, 180 nozzles) are formed. However, the number of nozzles is not limited in any way. Furthermore, the number of ink heads is not limited to four.

The ink heads 40A to 40D are connected to ink cartridges that store ink by ink supply paths (not shown). In this embodiment, the ink head 40A is connected to an ink cartridge that stores cyan ink and ejects cyan ink. The ink head 40B is connected to an ink cartridge that stores magenta ink and ejects magenta ink. The ink head 40C is connected to an ink cartridge that stores yellow ink and ejects yellow ink. The ink head 40D is connected to an ink cartridge that stores black ink and ejects black ink. However, the colors of ink ejected from each of the ink heads 40A to 40D are not limited to the above four types. In addition, there are no limitations on the ink material, and various materials that have been used as ink materials for inkjet printers in the past can be used. The ink may be, for example, a solvent-based pigment ink or a water-based pigment ink, or may be a water-based dye ink, or an ultraviolet-curable pigment ink that hardens when exposed to ultraviolet light.

Figure 3 is a partial cross-sectional view of the vicinity of one nozzle 41 of the ink head 40. The ink head 40 has a hollow case 51 having a plurality of pressure chambers 53 in which ink is stored. As shown in Figure 4, the plurality of pressure chambers 53 are arranged in the sub-scanning direction X. As shown in Figure 3, the ink head 40 has a plurality of vibration plates 52 attached to the case 51 so as to respectively partition a portion of the pressure chambers 53, and a plurality of piezoelectric elements 56 connected to each vibration plate 52. The piezoelectric elements 56 are an example of an actuator. The vibration plate 52 is elastically deformable inward and outward of the pressure chambers 53. The vibration plate 52 is configured to be deformable so as to increase and decrease the volume of the pressure chambers 53. The vibration plate 52 is typically a resin film or a metal foil.

As shown in FIG. 3, the case 51 is formed with a common flow path 58 through which ink supplied from an ink cartridge (not shown) flows. The case 51 is formed with an ink inlet 54 through which the ink flows. The ink inlet 54 only needs to be connected to the pressure chamber 53, and the position of the ink inlet 54 is not limited in any way. The ink inlet 54 is formed between the common flow path 58 and the pressure chamber 53. Ink is supplied to the pressure chamber 53 from the common flow path 58 through the ink inlet 54, and a predetermined amount of ink is temporarily stored therein. The ink that flows into the pressure chamber 53 through the ink inlet 54 is guided to the nozzle 41. As shown in FIG. 4, the nozzles 41 are formed on the lower surface 51B of the case 51. The nozzles 41 are each connected to the pressure chamber 53. The nozzles 41 eject ink toward the recording medium 5.

3, the piezoelectric element 56 is connected to the surface of the vibration plate 52 opposite to the pressure chamber 53 (here, the upper surface). Note that "connected" here includes both cases where the vibration plate 52 and the piezoelectric element 56 are directly connected and cases where they are indirectly connected via other members. The piezoelectric element 56 may or may not be in contact with the vibration plate 52. In this embodiment, the vibration plate 52 and the piezoelectric element 56 are directly connected. The piezoelectric element 56 is connected to the control device 100 via a flexible cable (not shown). An electric signal is supplied to the piezoelectric element 56 via the flexible cable. When the piezoelectric element 56 receives an electric signal from the control device 100, it expands or contracts, and functions to elastically deform the vibration plate 52 to the outside or inside of the pressure chamber 53. Here, a piezoelectric element (PZT) in a longitudinal vibration mode is used. The longitudinal vibration mode PZT is freely expandable in the lamination direction, and for example, contracts when discharged and expands when charged. However, the type of the piezoelectric element 56 is not particularly limited.

In the ink head 40 having such a configuration, for example, the potential of the piezoelectric element 56 is lowered from the reference potential, so that the piezoelectric element 56 contracts. Following this, the vibration plate 52 elastically deforms from the initial position to the outside of the pressure chamber 53, and the pressure chamber 53 expands. The expansion of the pressure chamber 53 means that the volume of the pressure chamber 53 increases due to the deformation of the vibration plate 52. Next, the potential of the piezoelectric element 56 is raised, so that the piezoelectric element 56 extends in the stacking direction. As a result, the vibration plate 52 elastically deforms to the inside of the pressure chamber 53, and the pressure chamber 53 contracts. The contraction of the pressure chamber 53 means that the volume of the pressure chamber 53 decreases due to the deformation of the vibration plate 52. The pressure in the pressure chamber 53 fluctuates due to the expansion and contraction of the pressure chamber 53. Due to this pressure fluctuation in the pressure chamber 53, the ink in the pressure chamber 53 is pressurized, and is ejected from the nozzle 41 as an ink droplet. After that, by returning the potential of the piezoelectric element 56 to the reference potential, the vibration plate 52 returns to its initial position and the pressure chamber 53 expands. At this time, ink flows into the pressure chamber 53 from the ink inlet 54.

As shown in FIG. 1, an operation panel 15 is provided on the right end of the printer body 10a. The operation panel 15 is provided with a display unit that displays the device status, and input keys that are operated by the user. Inside the operation panel 15, a control device 100 that controls various operations of the printer 10 is housed.

As shown in FIG. 5, the control device 100 is communicatively connected to the carriage motor 24 of the carriage movement mechanism 26, the feed motor 33 of the movement device 30, and the piezoelectric element 56 of the ink head 40. The control device 100 controls the operations of these devices. The control device 100 is typically a computer. The control device 100 includes an interface (I/F) that receives print data and the like from an external device such as a host computer, a central processing unit (CPU) that executes the commands of a control program, a ROM that stores the program executed by the CPU, a RAM that is used as a working area for expanding the program, and a storage device such as a memory that stores the above-mentioned program and various data.

As shown in FIG. 5, the control device 100 includes a drive signal generating unit 102, a drive signal supplying unit 104, a print mode selecting unit 106, an image printing unit 108, a test pattern printing unit 110, a correction value input unit 112, and a correction unit 114. The functions of each unit of the control device 100 are realized by a program. This program is read from a recording medium such as a CD or DVD. The program may be downloaded via the Internet. The functions of each unit of the control device 100 may be realized by a processor and/or a circuit. The specific functions of each unit will be described later.

The drive signal generating unit 102 generates a drive signal for driving the ink head 40 for each drive cycle. The drive signal includes one or more drive pulses. Each drive pulse has a drive voltage of 25V to 35V.

The drive signal supply unit 104 supplies a part or all of the drive signal generated by the drive signal generation unit 102 to each piezoelectric element 56 to eject ink from the nozzle 41 of the ink head 40. The drive signal supply unit can change the amount of ink ejected from the nozzle 41 of the ink head 40 during one drive cycle by appropriately selecting the drive pulse of the drive signal to be supplied to the piezoelectric element 56.

The print mode selection unit 106 is a section where the print mode of the printer 10 is selected. The print mode selection unit 106 is configured, for example, to display an operation screen on the display unit of the operation panel 15. The printer 10 according to this embodiment is configured to be able to select the "image printing mode" and the "bidirectional adjustment pattern printing mode" as print modes.

When the "image printing mode" is selected by the print mode selection unit 106, the image printing unit 108 controls the carriage motor 24, the feed motor 33, and the ink head 40 to print an image on the recording medium 5. The image printing unit 108 prints an image based on the input image data on the recording medium 5 by forward printing and backward printing. Here, "forward printing" means printing in which ink is ejected from the nozzle 41 onto the recording medium 5 while moving the ink head 40 in the forward direction (i.e., the first main scanning direction Y1), which is a direction from right to left in the main scanning direction Y. Also, "backward printing" means printing in which ink is ejected from the nozzle 41 onto the recording medium 5 while moving the ink head 40 in the backward direction (i.e., the second main scanning direction Y2), which is a direction from left to right in the main scanning direction Y. For example, the image printing unit 108 controls the feed motor 33 to move the recording medium 5 forward (downstream in the sub-scanning direction X) each time one forward printing and one backward printing are completed. The image printing unit 108 repeats forward printing, backward printing, and then transporting the recording medium 5 to print an image on the recording medium 5.

When the "bidirectional adjustment pattern printing mode" is selected by the printing mode selection unit 106, the test pattern printing unit 110 controls the carriage motor 24, feed motor 33, and ink head 40 to print multiple test patterns P0 to P40 (see FIG. 6) on the recording medium 5. As will be described in more detail below, the printed multiple test patterns P0 to P40 indicate the amount of deviation in the ink landing position between forward printing and backward printing. The test pattern printing unit 110 prints multiple test patterns P0 to P40 on the recording medium 5 by forward printing and backward printing.

The correction value input unit 112 receives a correction value obtained from the test pattern. The above input is input by a user. The correction unit 114 corrects the ink landing position (i.e., the timing of ink ejection) during backward printing by the correction value input to the correction value input unit 112. Details of the above correction will be described later.

As shown in FIG. 6, multiple test patterns P0 to P40 are arranged in the main scanning direction Y on the recording medium 5. Each of the test patterns P0 to P40 is composed of an outgoing pattern PY1 and a returning pattern PY2. The outgoing pattern PY1 is a pattern printed by outgoing direction printing. The outgoing pattern PY1 is an example of a first pattern. The outgoing pattern PY1 is printed, for example, by the first partial nozzle row 43A and the second partial nozzle row 43B of the nozzle 41. The returning pattern PY2 is a pattern printed by returning direction printing. The returning pattern PY2 is an example of a second pattern. The returning pattern PY2 is printed, for example, by the second partial nozzle row 43B and the third partial nozzle row 43C of the nozzle 41. The returning pattern PY2 is located upstream (i.e., rearward) of the outgoing pattern PY1 in the sub-scanning direction X. The check patterns P0 to P40 are each set with a correction value that corrects the deviation of the ink landing position between forward printing and backward printing. The check patterns P0 to P40 are arranged in the main scanning direction Y in the order of the correction values that have been set. Different numbers are printed in front of the check patterns P0 to P40 (downstream side in the sub-scanning direction X). These numbers are also printed as part of the check patterns P0 to P40. These numbers are printed at the downstream end of the check patterns P0 to P40 in the sub-scanning direction X. These numbers are, for example, the correction values. In the check patterns P0 to P40, the forward pattern PY1 and the backward pattern PY2 are set to be printed at positions separated by a predetermined shift amount in the main scanning direction Y. However, this is a setting in the printer 10 and does not refer to the actual printing positions. In this embodiment, the forward pattern PY1 is printed by one forward printing. Also, the backward pattern PY2 is printed by two backward printings. For example, the first backward print prints the even-numbered test pattern (P0, etc.), and the second backward print prints the odd-numbered test pattern (P1, etc.).

As shown in FIG. 6, the multiple printed test patterns P0 to P40 are visually confirmed by the user. In the example of FIG. 6, the user recognizes test pattern P18, which has a numerical value of "18" set, as the test pattern with the least deviation. The user then inputs "18" into correction value input unit 112. Correction unit 114 corrects the ink landing position during backward printing based on the correction value set for test pattern P18. This correction causes the misaligned ink landing position during forward printing to match the ink landing position during backward printing.

Here, in conventional printers, the drive signal for driving the ink head includes a drive pulse having a relatively low drive voltage (for example, 15V or more and less than 25V). This is because resonance is necessary to suppress the variation in ejection between adjacent nozzles. On the other hand, in this embodiment, a drive pulse having a relatively high drive voltage (for example, 25V or more and less than 35V) is used without deliberately resonating in order to suppress the variation in ejection between nozzles. However, as shown in FIG. 7, the inventor of the present application noticed that when ink is ejected from the nozzles 41 aligned in the sub-scanning direction X, the case 51 is deformed upward by applying a relatively high drive voltage to each piezoelectric element 56. It was discovered that such deformation affects the amount of deformation of the case 51 of the adjacent nozzles 41, and the more central the nozzle 41, the greater the deformation of the case 51. In other words, even though the amount of deformation of each piezoelectric element 56 is the same, the case 51 housing the piezoelectric element 56 expands greatly, causing a difference in the amount of change in the volume of the pressure chamber 53, and as a result, the inventor noticed that the amount of ink ejected from the nozzle 41 varies. Therefore, as shown in FIG. 8, the inventors of the present application have decided to set the ink to be ejected from some of the nozzles 41 arranged in the sub-scanning direction X in forward printing and backward printing, and the second nozzle 41B adjacent to the first nozzle 41A that ejects ink among the nozzles 41 not to eject ink. As a result, even if a portion of the case 51 located above the first nozzle 41A is deformed upward by applying a relatively high driving voltage to each piezoelectric element 56, ink is not ejected from the adjacent second nozzle 41B, so that the deformation of the case 51 does not affect the amount of deformation of the portion of the case 51 located above the other first nozzle 41A, and it is possible to suppress the occurrence of variations in the amount of ink ejected from the first nozzle 41A. In other words, the volume change amount of the pressure chamber 53 communicating with the first nozzle 41A can be made uniform. In this embodiment, one second nozzle 41B is set for the first nozzle 41A, but two or more second nozzles 41B may be set.

As described above, according to the printer 10 of this embodiment, when the test patterns P0 to P40 are printed on the recording medium 5 by forward printing and backward printing, the second nozzle 41B adjacent to the first nozzle 41A that ejects ink is set not to eject ink. This makes it possible to make the deformation amount of the case 51 deformed by each piezoelectric element 56 that changes the volume of the pressure chamber 53 of the multiple first nozzles 41A that eject ink at the same time almost the same. In other words, since the deformation amount of the multiple piezoelectric elements 56 is the same, the volume change amount of each pressure chamber 53 is also the same, and the same amount of ink can be ejected from the multiple first nozzles 41A at the same ejection speed. This makes it possible to more accurately print the test patterns P0 to P40 on the recording medium 5. As a result, bidirectional printing can be performed using a more appropriate correction value, and the quality of the image printed on the recording medium 5 by bidirectional printing can be improved.

In the printer 10 of this embodiment, the multiple nozzles 41 include a first partial nozzle row 43A located downstream in the sub-scanning direction X and used when printing the outgoing pattern PY1, a third partial nozzle row 43C located upstream in the sub-scanning direction X and used when printing the return pattern PY2, and a second partial nozzle row 43B located between the first partial nozzle row 43A and the third partial nozzle row 43C and used when printing the outgoing pattern PY1 and the return pattern PY2. This makes it possible to print the test patterns P0 to P40 on the recording medium 5 without moving the recording medium 5 in the sub-scanning direction X. In addition, the second partial nozzle row 43B prints the outgoing pattern PY1 and the return pattern PY2, so that the overlap between the outgoing pattern PY1 and the return pattern PY2 can be more clearly recognized.

In the printer 10 of this embodiment, the first print in the return direction prints the even-numbered return pattern PY2, and the second print in the return direction prints the odd-numbered return pattern PY2. For example, if the power sources of the odd-numbered nozzles and the even-numbered nozzles in one nozzle row are different, the odd-numbered return pattern PY2 or the even-numbered return pattern PY2 can be printed using the odd-numbered nozzles, and the odd-numbered return pattern PY2 or the remaining even-numbered return pattern PY2 can be printed using the even-numbered nozzles, thereby averaging the characteristic differences for each power source. In other words, the variation in printing due to the variation in the power source can be reduced.

In the printer 10 of this embodiment, the multiple test patterns P0 to P40 are configured to be arranged in the main scanning direction Y in order of their correction values. More specifically, the test patterns P0 to P40 are arranged in order, with smaller correction values on the left and larger correction values on the right. By arranging the test patterns P0 to P40 in this way, it is possible to configure test patterns P0 to P40 that are easy to recognize intuitively.

In the printer 10 of this embodiment, each of the multiple test patterns P0 to P40 includes characters that represent a correction value. This allows the user to easily recognize the correction value and input the correction value into the printer 10.

The above describes a preferred embodiment of the present invention. However, the above embodiment is merely an example, and the present invention can be implemented in various other forms.

In the embodiment described above, 41 test patterns P0 to P40 are printed on the recording medium 5 in the bidirectional adjustment pattern printing mode, but this is not limited to this. The number of test patterns can be set appropriately by the user.

In the embodiment described above, the return path pattern PY2 was printed by two return path printings, but it may be printed by one return path printing.

In the above-described embodiment, the return path pattern PY2 is printed upstream of the forward path pattern PY1 in the sub-scanning direction X, but it may also be printed downstream in the sub-scanning direction X.

In the above-described embodiment, the outward pattern PY1 is printed by the first partial nozzle row 43A and the second partial nozzle row 43B, and the return pattern PY2 is printed by the second partial nozzle row 43B and the third partial nozzle row 43C, but this is not limited to the above. For example, the outward pattern PY1 and the return pattern PY2 may be printed by the first partial nozzle row 43A, the second partial nozzle row 43B, and the third partial nozzle row 43C.

5 Recording medium 10 Printer (inkjet printer)
40 Ink head 41 Nozzle 41A First nozzle 41B Second nozzle 51 Case 52 Vibration plate 53 Pressure chamber 56 Piezoelectric element (actuator)
100 Control device 102 Drive signal generating unit 104 Drive signal supply unit 108 Image printing unit 110 Test pattern printing unit

Claims (3)

An ink head that ejects ink onto a recording medium;
a carriage that moves the ink head in a main scanning direction;
a moving device that moves the recording medium in a sub-scanning direction perpendicular to the main scanning direction;
a control device for controlling the ink head, the carriage, and the moving device;
The ink head is
a case having a plurality of pressure chambers formed therein for storing ink;
a plurality of vibration plates provided in the case and partitioning a portion of each of the pressure chambers;
A plurality of actuators connected to the diaphragms and deforming when an electric signal is supplied thereto;
a plurality of nozzles formed in the case, each of which is in communication with one of the pressure chambers and which are aligned in the sub-scanning direction;
The control device includes:
a drive signal generating unit that generates a drive signal including one or more drive pulses having a drive voltage of 25 V to 35 V for each drive period;
a drive signal supplying unit that supplies a part or all of the drive signals generated by the drive signal generating unit to each of the actuators to eject ink from the nozzles;
an image printing unit that prints an image based on image data on the recording medium by the forward direction printing and the backward direction printing, when printing in which ink is ejected from the nozzles onto the recording medium while moving the ink head in a forward direction that is a direction from one side of the main scanning direction to the other side is defined as forward direction printing, and printing in which ink is ejected from the nozzles onto the recording medium while moving the ink head in a backward direction that is a direction from the other side of the main scanning direction to one side is defined as backward direction printing;
a test pattern printing unit that prints, on the recording medium by the forward direction printing and the backward direction printing, a plurality of test patterns that are aligned in the main scanning direction and each of which has a correction value set to correct a deviation in the landing position of ink between the forward direction printing and the backward direction printing,
In the forward direction printing and the backward direction printing, ink is ejected from some of the plurality of nozzles, and a second nozzle adjacent to a first nozzle that ejects ink among the plurality of nozzles is set not to eject ink,
each of the test patterns includes a first pattern printed by the forward direction printing and a second pattern printed by the backward direction printing;
The plurality of nozzles include
a plurality of downstream nozzles located downstream in the sub-scanning direction and used when printing one of the first pattern and the second pattern;
a plurality of upstream nozzles located upstream in the sub-scanning direction and used when printing the other of the first pattern and the second pattern;
a plurality of central nozzles located between the downstream nozzles and the upstream nozzles and used when printing the first pattern and the second pattern;
the first pattern of each of the test patterns is printed by one forward pass printing,
the second pattern of each of the test patterns is printed by two reverse direction printings,
In the first backward direction printing, one of the odd-numbered second patterns and the even-numbered second patterns is printed,
The inkjet printer wherein the other of the odd-numbered second patterns and the even-numbered second patterns is printed by a second round of printing in the backward direction. the plurality of inspection patterns are arranged in the main scanning direction in order of the correction values.
2. The inkjet printer according to claim 1 . The inkjet printer according to claim 1 , wherein each of the plurality of test patterns includes a character representing the correction value.

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