JP2023183551A - liquid discharge device - Google Patents

Abstract

To provide means capable of suppressing a reduction in image quality of an image recorded on a discharge target medium when a nozzle array is disposed obliquely.SOLUTION: On a head 32 of a printer 10, four nozzle arrays K1 to K4 are aligned in a first inclination direction 5, and on each nozzle array, a plurality of nozzles 33 are aligned in a second inclination direction 6. A control part 40 allows a one-way record for discharging ink from the nozzles 33 by moving the head 32 leftward. The four nozzle arrays K1 to K4 are disposed obliquely to a front-back direction 8 so that between both ends of the nozzle array, one end which has a smaller distance from the nozzle 33 to a sheet S is positioned on the left of the other end in a right-left direction 9.SELECTED DRAWING: Figure 5

Description

The present invention relates to a liquid ejection device that ejects liquid onto a medium to be ejected.

Patent Document 1 describes an inkjet printer in which two nozzle rows are arranged one behind the other in the printing direction. One nozzle row is movable in a direction perpendicular to the printing direction (hereinafter referred to as the orthogonal direction). The two nozzle rows may be arranged obliquely with respect to the orthogonal direction.

Japanese Patent Application Publication No. 2002-210937

In the above conventional inkjet printer, when the nozzle array is arranged at an angle with respect to the orthogonal direction, the ruled lines that should be recorded on the ejection target medium in parallel to the printing direction or orthogonal direction are printed on the ejection target medium in the printing direction or perpendicular to the Recorded at an angle to the direction. Furthermore, in an inkjet printer that transports a medium to be ejected in the direction in which a nozzle row extends, the distance from the nozzle to the medium may differ between one end and the other end of the nozzle row. In this case, since the time taken for the ink ejected from the nozzle to land on the ejection target medium also differs, the ruled line is recorded on the ejection target medium at an angle. If both the inclination of the ruled line due to the inclination of the nozzle row and the inclination of the ruled line due to the difference in distance occur, the ruled line recorded on the ejected medium will be greatly inclined, and the image recorded on the ejected medium will be Image quality will deteriorate.

The present invention has been made in view of the above circumstances, and provides a means for suppressing deterioration in image quality of images recorded on an ejection target medium when nozzle rows are arranged at an angle. be.

(1) A liquid ejecting device of the present invention includes a head having a plurality of nozzles for ejecting liquid, and a head that is arranged relative to a medium to be ejected in a main scanning direction and a conveying direction intersecting the main scanning direction. It includes a moving mechanism that moves and a control section. The head includes a first nozzle row in which a plurality of nozzles are lined up in a predetermined direction. The control unit moves the head in a first direction along the main scanning direction to perform a first ejection operation of ejecting liquid from the nozzle, and moves the head in a first direction opposite to the first direction. It is possible to perform unidirectional recording in which an image is recorded on the ejection target medium without performing a second ejection operation in which liquid is ejected from the nozzle by moving in two directions. The first nozzle row is arranged such that one end of the first nozzle row, which has a smaller distance from the nozzle to the medium to be ejected, is located closer to the terminal end in the first direction than the other end. It is arranged at an angle to the direction.

In the liquid ejecting device, the first nozzle row is arranged at an angle with respect to the transport direction such that one end with a smaller distance from the nozzle to the medium to be ejected is located closer to the terminal end in the first direction than the other end. has been done. Therefore, when the head is moved in the first direction to perform unidirectional recording, the inclination of the image due to the difference in distance from the nozzle to the ejected medium can be reduced. Therefore, when the nozzle rows are arranged obliquely, it is possible to suppress deterioration in the image quality of images recorded on the ejection target medium.

(2) In the head, the first nozzle row and the second nozzle row are arranged in a first direction, and the first nozzle row and the second nozzle row have a plurality of nozzle rows arranged in a second direction intersecting the first direction. The nozzles are lined up, and the first nozzle row and the second nozzle row are such that, in the transport direction, the nozzles in the second nozzle row are between the nozzles in the first nozzle row and the nozzles adjacent to the nozzles. The second nozzle row, along with the first nozzle row, is arranged at an angle with respect to the conveying direction so that the second nozzle row is located at a distance from the nozzle to the medium to be ejected from both ends of the first nozzle row. may be arranged to be inclined with respect to the transport direction so that one end with a smaller distance is located closer to the terminal end in the first direction than the other end.

(3) Preferably, the control unit is capable of selectively performing the unidirectional recording and bidirectional recording in which an image is recorded on the ejected medium in the first ejection operation and the second ejection operation. It may be.

(4) Preferably, the control unit may shift the output timing of the ejection control signal of the nozzle by a larger amount in the second ejection operation than in the first ejection operation.

(5) Preferably, the control unit may increase the delay amount of the ejection control signal for the nozzle in the second ejection operation than in the first ejection operation.

(6) Preferably, when executing the bidirectional recording, the control unit may shift the output timing of the ejection control signal of the nozzle based on the ejection position of the immediately previous ejection operation.

(7) Preferably, in the second ejection operation, the control unit controls the delay amount of the ejection control signal of the nozzle for a nozzle on one end side and a nozzle on the other end side in each nozzle row included in the head. may be set to different amounts.

(8) Preferably, the control section may make the moving speed of the head slower in the second ejection operation than in the first ejection operation.

(9) Preferably, the nozzles in the first nozzle row are arranged in the second direction at intervals for forming dots at the first resolution, and the nozzles in the second nozzle row are arranged in the second direction at intervals for forming dots at the first resolution. The nozzles in the first nozzle row and the nozzles in the second nozzle row are arranged in a second direction at intervals for forming dots at the first resolution, and the nozzles in the first nozzle row and the nozzles in the second nozzle row Dots may be formed at twice the resolution.

(10) Preferably, in the head, a third nozzle row and a fourth nozzle row are arranged in the first direction together with the first nozzle row and the second nozzle row, and the third nozzle row and the fourth nozzle row In the row, a plurality of nozzles are lined up in the second direction, and the control unit performs a first operation of ejecting liquid of the same color from the nozzles in the first to fourth nozzle rows, and a first operation to eject liquid of the same color from the nozzles in the first to fourth nozzle rows. The second operation may be performed selectively with the second operation of ejecting liquid of a color corresponding to each nozzle row from the nozzles in the nozzle row.

According to the present invention, when the nozzle array is arranged obliquely, it is possible to suppress deterioration in the quality of the image recorded on the ejection target medium.

FIG. 1 is an external perspective view of a printer 10 according to an embodiment of the invention. FIG. 2 is a vertical cross-sectional view schematically showing the internal structure of the printer 10. As shown in FIG. FIG. 3 is a block diagram of the printer 10. FIG. 4 is a diagram showing the arrangement of the head 32 and nozzles 33, and the recording positions of dots. FIG. 5(A) is a diagram showing an example of the distance from the nozzle 33 to the sheet S, and FIG. 5(B) is a diagram showing the inclined arrangement of the nozzle rows in this case. FIG. 6(A) is a diagram showing another example of the distance from the nozzle 33 to the sheet S, and FIG. 6(B) is a diagram showing the inclined arrangement of the nozzle rows in this case. FIG. 7 is a flowchart of the one-way printing process of the printer 10. FIG. 8(A) is a diagram showing the recording position by the printer according to the first comparative example, FIG. 8(B) is a diagram showing the recording position by the printer according to the second comparative example, and FIG. ) is a diagram showing recording positions by the printer 10. FIG. 9 is a flowchart of bidirectional recording processing of the printer according to the first modification. FIG. 10(A) is a diagram showing the printing position by the printer 10, and FIG. 10(B) is a diagram showing the printing position by the printer according to the first modification. FIG. 11 is a flowchart of bidirectional recording processing of the printer according to the second modification. FIG. 12 is a diagram showing recording positions by the printer according to the second modification. FIG. 13(A) is a diagram showing the printing position by the printer according to the third comparative example, and FIG. 13(B) is a diagram showing the printing position by the printer according to the third modification.

Embodiments of the present invention will be described below. Note that the embodiments described below are merely examples of the present invention, and it goes without saying that the embodiments of the present invention can be modified as appropriate without changing the gist of the present invention. In the following explanation, the progress from the starting point of the arrow to the ending point is expressed as the direction, and the movement on the line connecting the starting point and the ending point of the arrow is expressed as the direction. Further, a vertical direction 7 is defined based on the state in which the printer 10 is installed so that it can be used (the state shown in FIG. 1), a front-back direction 8 is defined with the surface where the opening 13 of the printer 10 is formed as the front, and the printer 10 A left-right direction 9 is defined when viewed from the front. The up-down direction 7, the front-back direction 8, and the left-right direction 9 are orthogonal to each other.

[Overview of printer 10]
The printer 10 according to this embodiment is an example of a liquid ejection device that ejects liquid onto a medium to be ejected. The printer 10 is a monochrome printer that ejects black ink (an example of a liquid) onto a sheet (an example of a medium to be ejected) using an inkjet printing method. The printer 10 may be a so-called "multifunction device" having functions such as a facsimile function, a scan function, and a copy function.

The printer 10 has a housing 11 having a generally rectangular parallelepiped shape. As shown in FIGS. 1 and 2, inside the casing 11 are a feeding tray 14, a feeding roller 21, a pair of conveying rollers 22, a carriage 31, and a plurality of nozzles mounted on the carriage 31. 33, a platen 23 facing the head 32, a pair of ejection rollers 24, an ejection tray 15, a sub-tank 35, a mounting case 36 into which a cartridge 37 can be mounted, and a cartridge mounted in the mounting case 36. 37 and a tube 34 that communicates with the head 32 are located. The conveying roller pair 22 includes a driving roller 22a and a driven roller 22b. The discharge roller pair 24 includes a driving roller 24a and a driven roller 24b. When the printer 10 is viewed from the left, the plurality of nozzles 33 are lined up in the front-rear direction 8 in the head 32.

The printer 10 drives the feeding roller 21 and the driving roller 22a of the pair of conveying rollers 22 to move the sheet supported on the feeding tray 14 to the platen along a conveying path (path indicated by a dashed line in FIG. 2). Convey to position 23. Next, the printer 10 causes the nozzle 33 of the head 32 to eject ink supplied from the cartridge 37 mounted in the mounting case 36 via the sub tank 35 and the tube 34 . As a result, the ink lands on the sheet supported by the platen 23, and an image is recorded on the sheet. The printer 10 drives the driving roller 24a of the ejection roller pair 24 to eject the sheet on which the image is recorded onto the ejection tray 15.

The carriage 31 is supported by two guide rails (not shown) extending in the left-right direction 9 and reciprocates in the left-right direction 9 intersecting the front-back direction 8 . The printer 10 causes ink to be ejected from the nozzles 33 of the head 32 while the carriage 31 moves in the left-right direction 9 . As a result, an image is recorded on a partial area of the sheet facing the head 32. Next, the printer 10 causes the pair of transport rollers 22 to transport the sheet so that the area where an image is to be recorded next faces the head 32. An image is recorded on the sheet by alternately and repeatedly performing these processes.

Note that the left-right direction 9 is an example of the main scanning direction. The front-rear direction 8 is an example of a transport direction that intersects with the main scanning direction. The transport roller pair 22, the discharge roller pair 24, and the carriage 31 are an example of a moving mechanism that moves the head 32 relative to the sheet in the main scanning direction and the transport direction.

As shown in FIG. 1, the housing 11 includes a cover 18 on the front surface 12 of the housing 11 and at the right end in the left-right direction 9. As shown in FIG. An opening (not shown) is formed at the position of the cover 18 . The cover 18 is rotatable between a position where the opening is closed (the position shown in FIG. 1) and a position where the opening is opened. One mounting case 36 is located in the housing space inside the housing 11 that extends deep into the opening. A cartridge 37 storing black ink is attached to the attachment case 36 .

The cartridge 37 has a liquid chamber 38 (see FIG. 2) that can store ink. When the cartridge 37 is attached to the attachment case 36, the ink stored in the liquid chamber 38 flows into the sub-tank 35 via an ink flow path 39 that communicates the liquid chamber 38 and the sub-tank 35. The sub-tank 35 temporarily stores the ink that has flowed into it. Ink stored in the sub tank 35 is supplied to the head 32 via the tube 34.

[Control unit 40]
A control unit 40 shown in FIG. 3 is located inside the casing 11. The control unit 40 includes a CPU 41, a ROM 42, a RAM 43, an EEPROM 44, and an ASIC 45. The ROM 42 stores programs and the like for the CPU 41 to execute various processes. The RAM 43 is used as a storage area for temporarily recording data, signals, etc. used when the CPU 41 executes a program, or as a work area for data processing. The EEPROM 44 stores information that should be retained even after the power is turned off. The control unit 40 executes various processes by causing the CPU 41 to execute programs stored in the RAM 43.

The ASIC 45 is for operating the feed roller 21, the drive roller 22a of the transport roller pair 22, the drive roller 24a of the discharge roller pair 24, the carriage 31, and the head 32. The control unit 40 rotates the feeding roller 21 and the drive rollers 22a and 24a by driving a motor (not shown) through the ASIC 45. The control unit 40 moves the carriage 31 in the left-right direction 9 by driving a motor (not shown) through the ASIC 45 . The control unit 40 causes ink to be ejected from the nozzles 33 of the head 32 by outputting an ejection control signal to a drive element (not shown) of the head 32 through the ASIC 45 . The ASIC 45 outputs an ejection control signal according to the amount of ink to be ejected from the nozzle 33.

A display 16 and an operation panel 17 are connected to the ASIC 45 . The display 16 is, for example, a liquid crystal display, an organic EL display, or the like. The display 16 displays, for example, the status of the printer 10 on a screen. The operation panel 17 outputs an operation signal according to a user's operation to the control unit 40. The operation panel 17 may include, for example, push buttons or a touch sensor superimposed on the display 16.

[Arrangement of head 32 and nozzle 33]
FIG. 4 shows the arrangement of the head 32 and nozzles 33, and the recording positions of dots. In FIG. 4, the horizontal direction is the left-right direction 9 (the moving direction of the carriage 31), and the vertical direction is the front-back direction 8 (the sheet conveyance direction). The white circles shown in FIG. 4 indicate the positions of the nozzles 33 when the head 32 is viewed from above. The black circles shown in FIG. 4 indicate the positions where dots are recorded by ink ejected from the nozzles 33.

The first inclination direction 5 and the second inclination direction 6 shown in FIG. 4 are directions inclined by a predetermined angle (hereinafter referred to as angle θ) from the left-right direction 9 and the front-back direction 8, respectively. The head 32 is mounted on the carriage 31 so as to be inclined at an angle θ with respect to the front-rear direction 8 and the left-right direction 9 along the first inclination direction 5 and the second inclination direction 6. In the head 32, the first to fourth nozzle rows K1 to K4 are arranged at equal intervals in the first inclination direction 5. In the first to fourth nozzle rows K1 to K4, a plurality of nozzles 33 are lined up at equal intervals in the second inclination direction 6. The second inclination direction 6 is a direction that intersects the first inclination direction 5, and specifically, a direction that is perpendicular to the first inclination direction 5. Although four nozzles 33 are shown in each nozzle row in FIG. 4, the number of nozzles 33 in each nozzle row is actually greater than four. The first inclination direction 5 is an example of a first direction. The second inclination direction 6 is an example of a second direction that intersects with the first direction.

As shown in FIG. 4, in the front-rear direction 8, between the nozzles 33 in the first row in the first nozzle row K1 and the nozzles 33 in the second row in the first nozzle row K1, the second nozzle row The first row nozzles 33 in K2, the first row nozzles 33 in the third nozzle row K3, and the first row nozzles 33 in the fourth nozzle row K4 are located. These five nozzles 33 are arranged at equal intervals in the front-rear direction 8. In this way, the first nozzle row K1 and the second nozzle row K2 are such that, in the front-rear direction 8, there is a gap between the nozzle 33 in the first nozzle row K1 and the nozzle 33 adjacent to the nozzle 33 in the second nozzle row K2. It is arranged obliquely with respect to the front-rear direction 8 so that the nozzle 33 is located therein.

By ejecting ink from the nozzles 33 in the first to fourth nozzle rows K1 to K4, dots are recorded at positions indicated by black circles in FIG. If the distance in the front-rear direction 8 between the nozzles 33 in the first row in the first nozzle row K1 and the nozzles 33 in the second row in the first nozzle row K1 is D, the front and back distance between the two recorded dots is The distance in direction 8 is D/4. Therefore, when the nozzles 33 in the first to fourth nozzle rows K1 to K4 are arranged in the second inclination direction 6 at intervals for forming dots at the first resolution, the nozzles 33 in the first to fourth nozzle rows K1 to K4 The nozzles 33 in the four nozzle rows K1 to K4 form dots in the front-rear direction 8 at a resolution four times the first resolution. Further, the nozzles 33 in the first nozzle row K1 and the nozzles 33 in the second nozzle row K2 form dots in the front-rear direction 8 at a resolution twice as high as the first resolution.

[Ink ejection control]
The control unit 40 outputs an ejection control signal to each nozzle 33 included in the head 32 according to the amount of ink to be ejected from each nozzle 33. The control unit 40 executes control to shift the output timing of the ejection control signal of the nozzle 33 for each nozzle row. Furthermore, a delay circuit (not shown) is located between the control unit 40 and the nozzle 33 to delay the ejection control signal. The delay circuit is built into the ASIC 45, for example.

Two delay amounts in the delay circuit can be set for each nozzle row. Of both ends of the nozzle row, in the front-rear direction 8, the end located at the rear (upstream in the transport direction) is referred to as the "upstream end", and the end located at the front (downstream in the transport direction) is referred to as the "downstream end". It is divided into a part near the end and a part near the downstream end (hereinafter, the former will be referred to as the "upstream side" and the latter as the "downstream side"). Of the two delay amounts corresponding to each nozzle row, one is applied to the ejection control signal for the upstream nozzle 33 in the nozzle row, and the other is applied to the ejection control signal for the downstream nozzle 33 in the nozzle row. Ru.

Hereinafter, the operation in which the control unit 40 moves the head 32 leftward to eject ink from the nozzles 33 will be referred to as a "first ejection operation," and the operation in which the control unit 40 moves the head 32 rightward to eject ink from the nozzles 33 will be referred to as a "first ejection operation." This is referred to as a "second ejection operation." The control unit 40 performs unidirectional recording in which ink is ejected from the nozzles 33 when the head 32 is moved leftward, and an image is recorded on the sheet without ejecting ink from the nozzles 33 when the head 32 is moved rightward. It is doable. That is, the control unit 40 can perform one-way printing in which an image is recorded on a sheet by performing the first ejection operation and not performing the second ejection operation.

[Inclination arrangement of nozzle rows according to the distance to the sheet]
In the printer 10, the distance from the nozzle 33 to the sheet may differ between the upstream end and the downstream end of the nozzle row. In the example shown in FIG. 5A, the distance d2 from the nozzle E2 at the downstream end in the first nozzle row K1 to the sheet S is the distance from the nozzle E1 at the upstream end in the first nozzle row K1 to the sheet S. smaller than d1. On the other hand, in the example shown in FIG. 6(A), the distance d1 from the nozzle E1 at the upstream end in the first nozzle row K1 to the sheet S is the distance d1 from the nozzle E2 at the downstream end in the first nozzle row K1 to the sheet S. is smaller than the distance d2.

When the distance from the nozzle 33 to the sheet S is small, the time it takes for the ink ejected from the nozzle 33 to land on the sheet S is short, so the dots on the sheet S are recorded from the position of the nozzle 33 when the ink is ejected. The distance to the location is small. On the other hand, if the distance from the nozzle 33 to the sheet S is long, the time it takes for the ink ejected from the nozzle 33 to land on the sheet S is long, so the dots on the sheet S from the position of the nozzle 33 when the ink is ejected are The distance to the recording position is large. Therefore, when ink is ejected from a plurality of nozzles 33 at the same timing, the greater the distance from the nozzles 33 to the sheet S, the more the dot recording position shifts in the direction in which the head 32 moves.

Therefore, in order to align the recording positions of dots regardless of the distance from the nozzle 33 to the sheet S, when the distance from the nozzle 33 to the sheet S is small, it is better to , the position of the nozzle 33 may be shifted in the direction in which the head 32 moves. Specifically, the first to fourth nozzle rows K1 to K4 are arranged such that one end of the first nozzle row K1, which has a smaller distance from the nozzle 33 to the sheet S, is located to the left of the other end. , it suffices if they are arranged obliquely with respect to the front-rear direction 8.

In the example shown in FIG. 5(A), the distance d2 is smaller than the distance d1. In this case, the first to fourth nozzle rows K1 to K4 are arranged such that the nozzle E2 at the downstream end in the first nozzle row K1 is located to the left in the left-right direction 9 than the nozzle E1 at the upstream end in the first nozzle row K1. It is arranged obliquely with respect to the front-rear direction 8 (see FIG. 5(B)).

On the other hand, in the example shown in FIG. 6(A), the distance d1 is smaller than the distance d2. In this case, the first to fourth nozzle rows K1 to K4 are arranged such that the nozzle E1 at the upstream end in the first nozzle row K1 is located to the left in the left-right direction 9 than the nozzle E2 at the downstream end in the first nozzle row K1. 6(B)).

[Details of unidirectional recording processing]
With reference to FIG. 7, one-way printing processing by the printer 10 will be explained. The control unit 40 executes the unidirectional recording process by performing the first ejection operation in a plurality of passes according to the flowchart shown in FIG. 7 . A pass means one operation of moving the head 32 in a certain direction to record an image.

In the flowcharts shown in FIG. 7, FIG. 9, and FIG. 11, when the control unit 40 sets different amounts for the two delay amounts corresponding to each nozzle row, it is expressed as “with split delay control,” and the control unit When 40 sets the same amount for two delay amounts corresponding to each nozzle row, it is written as "no split delay control." In addition, when the control unit 40 adjusts the output timing of the ejection control signal based on the printing position of the previous pass, it is written as “soft tilt adjustment”, and the control unit 40 adjusts the output timing of the ejection control signal based on the printing position of the previous pass. If the output timing is not adjusted, it is written as "no soft slope adjustment". Note that the print position of the previous pass is an example of the ejection position of the immediately previous ejection operation.

At the beginning of the one-way recording process shown in FIG. 7, the control unit 40 allocates image data to be recorded to each pass (S101). Next, the control unit 40 sets the value of the variable n to 1 (S102). The variable n indicates the pass number.

Next, the control unit 40 executes the nth pass recording while moving the head 32 leftward (S103). In S103, the control unit 40 sets the two delay amounts corresponding to each nozzle row to the same amount (for example, zero) (no split delay control), and adjusts the output timing of the ejection control signal based on the printing position of the previous pass. No (no soft tilt adjustment).

Next, the control unit 40 determines whether recording is completed (S104). If the control unit 40 determines that recording has not been completed (S104: No), the process proceeds to S105. The control unit 40 moves the head 32 rightward in S105. However, in S105, the control unit 40 does not eject ink from the nozzles 33 of the head 32 and does not perform image recording. Next, the control unit 40 transports the sheet by a predetermined amount (S106). Next, the control unit 40 adds 1 to the value of the variable n (S107). Next, the control unit 40 proceeds to S103 and executes the processes from S103 onwards again. If the control unit 40 determines in S104 that recording has been completed (S104: Yes), it ends the one-way recording process.

[Effect of tilted arrangement of nozzle rows]
With reference to FIG. 8, the effects of the printer 10 according to this embodiment will be explained. A first comparative example is a printer in which the distance from the nozzle to the sheet is different between the upstream end and the downstream end of the nozzle row, and the nozzle row is not arranged at an angle. In the printer according to the first comparative example, when the unidirectional recording process is performed by performing the first ejection operation (the operation of ejecting ink from the nozzles 33 while moving the head 32 leftward), FIG. As shown, an image is recorded on the sheet obliquely in each pass. Therefore, in the printer according to the first comparative example, the image quality of the image recorded on the sheet deteriorates.

A second comparative example is a printer in which the distance from the nozzle to the sheet is different between the upstream end and the downstream end of the nozzle row, and the nozzle row is arranged inclined in the opposite direction to the printer 10. In the printer according to the second comparative example, when the unidirectional recording process is performed by the first ejection operation, the image is recorded on the sheet obliquely for each pass, as shown in FIG. 8(B). In this case, both the image tilt due to the tilt of the nozzle row and the image tilt due to the difference in distance from the nozzles to the sheet occur. Therefore, in the printer according to the second comparative example, the image quality of the image recorded on the sheet is lower than that in the printer according to the first comparative example.

On the other hand, in the printer 10 according to the present embodiment, if the distance from the nozzle 33 to the sheet differs between the upstream end and the downstream end of the nozzle row, the first to fourth nozzle rows K1 to K4 are , among both ends of the nozzle row, the end with the smaller distance from the nozzle 33 to the sheet is located to the left of the other end in the left-right direction 9 (that is, located on the side where the head 32 advances in the first ejection operation). It is arranged to be inclined with respect to the front-rear direction 8. By performing the unidirectional recording process under such conditions, the inclination of the image due to the difference in distance from the nozzle 33 to the sheet can be reduced by the inclination arrangement of the nozzle rows. For example, by arranging the first to fourth nozzle rows K1 to K4 at a suitable angle, an image with no inclination or an image with a small inclination can be recorded on the sheet (see FIG. 8(C)). Deterioration in image quality of recorded images can be suppressed.

[Operations and effects of embodiment]
As shown above, the printer 10 according to this embodiment includes the head 32, a moving mechanism, and a control section 40. The head 32 includes a first nozzle row K1 in which a plurality of nozzles 33 are lined up in a predetermined direction. The control unit 40 performs unidirectional recording in which the head 32 is moved to the left to eject ink from the nozzles 33 and the head 32 is moved to the right to record an image on the sheet S without ejecting liquid from the nozzles 33. It is doable. The first nozzle row K1 is inclined with respect to the front-rear direction 8 such that one end with a smaller distance from the nozzle 33 to the sheet S is located to the left of the other end of both ends of the first nozzle row K1. It is located.

Therefore, when the head 32 is moved leftward and ink is ejected from the nozzles 33 to perform unidirectional recording, the inclination of the image due to the difference in distance from the nozzles 33 to the sheet S can be reduced. Therefore, when the nozzle rows are arranged obliquely, deterioration in the quality of images recorded on the sheet S can be suppressed.

Further, in the head 32, the first nozzle row K1 and the second nozzle row K2 are arranged in the first inclination direction 5, and in the first nozzle row K1 and the second nozzle row K2, a plurality of nozzles 33 are arranged in the second inclination direction 6. line up. Further, in the head 32, a third nozzle row K3 and a fourth nozzle row K4 are arranged in the first inclination direction 5 together with the first nozzle row K1 and the second nozzle row K2, and the third nozzle row K3 and the fourth nozzle row K4 are arranged in the first inclination direction 5. Here, a plurality of nozzles 33 are lined up in the second inclination direction 6. The second nozzle row K2, together with the first nozzle row K1, is arranged in the front-rear direction so that one end with a smaller distance from the nozzle 33 to the sheet S is located to the left of the other end. 8. Therefore, when a plurality of nozzle rows are arranged at an angle, deterioration in the image quality of the image recorded on the sheet S can be suppressed.

Further, the nozzles 33 in the first nozzle row K1 are arranged in the second inclination direction 6 at intervals for forming dots at the first resolution, and the nozzles 33 in the second nozzle row K2 are arranged in the second inclination direction 6 at intervals for forming dots at the first resolution. The nozzles 33 in the first nozzle row K1 and the nozzles in the second nozzle row K2 are arranged at intervals to form dots at the first resolution in the inclination direction 6, and the nozzles 33 in the first nozzle row K1 and the nozzles in the second nozzle row K2 are arranged at the first resolution in the front-rear direction 8. Forms dots with twice the resolution. Therefore, the nozzles 33 in the first nozzle row K1 and the nozzles in the second nozzle row K2 can form dots in the front-back direction 8 at twice the original resolution.

Regarding the printer 10 according to the above embodiment, various modifications can be made. The printers according to the first to third modifications have the same configuration as the printer 10 according to the above embodiment. In the printers according to the first to third modifications, in addition to one-way printing, the control unit 40 performs a first ejection operation (an operation of moving the head 32 leftward to eject ink from the nozzles 33) and a second ejection operation. Bidirectional recording can be performed to record an image on a sheet by both operations (moving the head 32 to the right and ejecting ink from the nozzles 33). The control unit 40 can selectively perform unidirectional recording and bidirectional recording. According to the printers according to the first to third modifications, the head 32 is moved in a predetermined direction to eject ink, the head 32 is moved in the opposite direction and the ink is not ejected, and the head 32 is moved in a predetermined direction. Bidirectional printing in which ink is ejected by moving in one direction and the other direction can be selectively performed. Bidirectional printing performed by the printers according to the first to third modified examples will be described below with reference to FIGS. 9 to 12.

[First modification]
In the printer according to the first modification, the control unit 40 performs the bidirectional ejection operation by performing the first ejection operation in the odd-numbered passes and the second ejection operation in the even-numbered passes according to the flowchart shown in FIG. Execute recording processing. At the beginning of the bidirectional recording process shown in FIG. 9, the control unit 40 allocates image data to be recorded to each pass (S201). Next, the control unit 40 sets the value of a variable n indicating the path number to 1 (S202).

Next, the control unit 40 determines whether the value of the variable n is an odd number (S203). If the control unit 40 determines that the value of the variable n is an odd number (S203: Yes), the process proceeds to S204. In this case, the control unit 40 moves the head 32 leftward and executes the nth pass recording (S204). In S204, the control unit 40 sets the same amount for the two delay amounts corresponding to each nozzle row (no split delay control), and does not adjust the output timing of the ejection control signal based on the printing position of the previous pass (soft slope). (no adjustment).

If the control unit 40 determines in S203 that the value of the variable n is not an odd number (S203: No), the process proceeds to S205. In this case, the control unit 40 moves the head 32 rightward and executes the nth pass recording (S205). In S205, the control unit 40 sets different amounts for the two delay amounts corresponding to each nozzle row (with split delay control), and does not adjust the output timing of the ejection control signal based on the printing position of the previous pass (with soft slope). (no adjustment).

After executing S204 or S205, the control unit 40 proceeds to S206. In S206, the control unit 40 determines whether recording has been completed. If the control unit 40 determines that recording has not been completed (S206: No), the process proceeds to S207. In S207, the control unit 40 transports the sheet by a predetermined amount. Next, the control unit 40 adds 1 to the value of the variable n (S208). Next, the control unit 40 proceeds to S203 and executes the processes from S203 onwards again. If the control unit 40 determines in S206 that recording has been completed (S206: Yes), it ends the bidirectional recording process.

In the printer 10 according to the embodiment described above, when the control unit 40 moves the head 32 leftward to perform the first ejection operation, the inclination of the image recorded on the sheet S is suppressed. The first to fourth nozzle rows K1 to K4 are arranged at an angle. Therefore, in the printer 10, when the control unit 40 moves the head 32 rightward to perform the second ejection operation, the inclination of the image recorded on the sheet S becomes larger due to the inclination arrangement of the nozzle rows. . For example, if the first ejecting operation is performed in an odd-numbered pass and the second ejecting operation is performed in an even-numbered pass, as shown in FIG. Images with no slope or images with a small slope are recorded, whereas images with a large slope are recorded on the sheet in the even-numbered passes.

Therefore, in the printer according to the first modification, the control unit 40 sets different amounts for the two delay amounts corresponding to each nozzle row in S205. For example, in S205, the control unit 40 sets the delay amount corresponding to the upstream side of each nozzle row to an amount corresponding to the tilt of the image recorded in an even-numbered pass, and sets the delay amount corresponding to the upstream side of each nozzle row to Set the delay amount to zero. As a result, in the even-numbered passes, images divided into two parts in eight directions in the front and rear directions are recorded on the sheet. In addition, by setting suitable amounts for the two delay amounts, as shown in FIG. 10(B), one recording position of the divided image and the other recording position of the divided image can be arranged. Therefore, according to the printer according to the first modification, the inclination of the image recorded by the second ejection operation can be suppressed more than the printer 10 according to the embodiment described above.

In the printer according to the first modification, in the second ejection operation, the control unit 40 controls the ejection control signal of the nozzle 33 for the upstream nozzle 33 and the downstream nozzle 33 in each nozzle row included in the head 32. Set the delay amount to a different amount. In this way, when the head 32 is moved rightward to perform the second ejection operation, the ejection control signal is delayed by different amounts between the upstream nozzle and the downstream nozzle in the nozzle row. Also, when performing the second ejection operation, the inclination of the image due to the difference in distance between the nozzle 33 and the sheet can be reduced.

[Second modification]
In the printer according to the second modification, the control unit 40 performs the bidirectional ejection operation by performing the first ejection operation in the odd-numbered passes and the second ejection operation in the even-numbered passes, according to the flowchart shown in FIG. Execute recording processing. At the beginning of the bidirectional recording process shown in FIG. 11, the control unit 40 allocates image data to be recorded to each pass (S301). Next, the control unit 40 moves the head 32 leftward to execute the first pass recording (S302). In S302, the control unit 40 sets the same amount for the two delay amounts corresponding to each nozzle row (no split delay control), and does not adjust the output timing of the ejection control signal based on the printing position of the previous pass (soft slope). (no adjustment).

Next, the control unit 40 moves the head 32 to the right and executes the second pass recording (S303). In S303, the control unit 40 sets different amounts for the two delay amounts corresponding to each nozzle row (with split delay control), and does not adjust the output timing of the ejection control signal based on the printing position of the previous pass (with soft slope). (no adjustment). Next, the control unit 40 sets the value of the variable n indicating the path number to 2 (S304).

Next, the control unit 40 determines whether the value of the variable n is an odd number (S305). If the control unit 40 determines that the value of the variable n is an odd number (S305: Yes), the process proceeds to S306. In this case, the control unit 40 moves the head 32 leftward and executes the nth pass recording (S306). In S306, the control unit 40 sets the same amount for the two delay amounts corresponding to each nozzle row (no split delay control), and adjusts the output timing of the ejection control signal based on the printing position of the previous pass (soft slope). (with adjustments).

If the control unit 40 determines in S305 that the value of the variable n is not an odd number (S305: No), the process proceeds to S307. In this case, the control unit 40 moves the head 32 rightward and executes the nth pass recording (S307). In S307, the control unit 40 sets different amounts for the two delay amounts corresponding to each nozzle row (with split delay control), and adjusts the output timing of the ejection control signal based on the printing position of the previous pass (with soft slope). (with adjustments).

After executing S306 or S307, the control unit 40 proceeds to S308. In S308, the control unit 40 determines whether recording has been completed. If the control unit 40 determines that recording has not been completed (S308: No), the process proceeds to S309. In S309, the control unit 40 transports the sheet by a predetermined amount. Next, the control unit 40 adds 1 to the value of the variable n (S310). Next, the control unit 40 proceeds to S305 and executes the processes from S305 onwards again. If the control unit 40 determines in S308 that recording has been completed (S308: Yes), it ends the bidirectional recording process.

When bidirectional printing is performed in the printer according to the first modification, a deviation occurs between the printing position of the even-numbered pass and the printing position of the odd-numbered pass immediately after that (see FIG. 10(B)). (See Part X).

Therefore, in the printer according to the second modification, the control unit 40 adjusts the output timing of the ejection control signal based on the printing position of the previous pass in S306 and S307. For example, the control unit 40 adjusts the output timing of the ejection control signal so that the print position of the previous pass and the print position of the next pass are aligned. This makes it possible to eliminate or reduce the deviation between the recording position of the even-numbered pass and the recording position of the odd-numbered pass immediately after it (see section Y in FIG. 12).

In FIG. 12, Si (i is an integer of 1 or more) indicates the recording start position of the i-th pass. The control unit 40 adjusts the output timing of the ejection control signal so that the printing position of the second pass and the printing position of the third pass are aligned. Therefore, the recording start position S3 of the third pass is a position shifted to the right by a distance D from the recording start position S1 of the first pass. The control unit 40 adjusts the output timing of the ejection control signal so that the printing position of the third pass and the printing position of the fourth pass are aligned. Therefore, the recording start position S4 of the fourth pass is a position shifted to the right by the distance D from the recording start position S2 of the second pass. The recording start position of each pass after the third pass is a position shifted to the right by a distance D from the recording start position of the two previous passes.

As described above, in the printer according to the second modification, when performing bidirectional printing, the control unit 40 shifts the output timing of the ejection control signal of the nozzle 33 based on the ejection position of the immediately previous ejection operation. Therefore, by aligning the ejection position of the previous ejection operation with the ejection position of the current ejection operation, it is possible to suppress deterioration in the image quality of the image recorded on the sheet S.

In the printer according to the second modification, similarly to the printer 10 according to the embodiment described above, an image with no slope or an image with a small slope is recorded on the sheet in the odd-numbered pass in which the first ejection operation is executed. On the other hand, in the even-numbered passes in which the second ejection operation is performed, an image with a large slope is recorded on the sheet. Therefore, the control unit 40 may shift the output timing of the ejection control signal of the nozzle 33 by a larger amount in the second ejection operation than in the first ejection operation. Alternatively, the control unit 40 may make the delay amount of the ejection control signal for the nozzle 33 larger in the second ejection operation than in the first ejection operation. By suitably controlling the ink ejection start position with respect to the sheet using such a method, the inclination of the image due to the difference in distance between the nozzle 33 and the sheet S can be reduced even when performing the second ejection operation.

[Third modification]
In the printer according to the third modification, the control unit 40 sets different amounts for the two delay amounts corresponding to each nozzle row in both the first ejection operation and the second ejection operation (with split delay control), and , the output timing of the ejection control signal of the nozzle 33 is adjusted based on the printing position of the previous pass (with soft tilt adjustment).

A third comparative example is a printer in which the distance from the nozzle to the sheet is different between the upstream end and the downstream end of the nozzle row, the nozzle row is arranged at an inclination, and the soft inclination adjustment is performed but the split delay control is not performed. shall be. When bidirectional printing is performed in the printer according to the third comparative example, as shown in FIG. 13(A), images are printed on the sheet obliquely for each pass. In the example shown in FIG. 13A, the printing positions of even-numbered passes are more inclined in the opposite direction to the printing positions of odd-numbered passes.

On the other hand, when performing bidirectional printing in the printer according to the third modification, the control unit 40 sets the distance D1 (FIG. 13 (see (B))), and in the even-numbered passes, a difference corresponding to the distance D2 is set for the two delay amounts corresponding to each nozzle row. Note that the distance D2 is greater than the distance D1.

As a result, as shown in FIG. 13(B), the recording position of one of the divided images is aligned with the recording position of the other divided image for the odd-numbered passes and the even-numbered passes. At the same time, it is possible to eliminate or reduce the deviation between the print position of the previous pass and the print position of the next pass. According to the printer according to the third modification, it is possible to suppress the inclination of the image recorded by the first ejection operation and the second ejection operation, and to suppress the deterioration in the image quality of the image recorded on the sheet.

In the printers according to the first to third modifications, the control unit 40 may make the speed when moving the head 32 rightward slower than the speed when moving the head 32 leftward. That is, the control unit 40 may make the moving speed of the head 32 slower in the second ejection operation than in the first ejection operation.

In the printers according to the first to third modifications, when the head 32 is moved to the right and the second ejection operation is performed, the dots are more The recording position is likely to shift. On the other hand, if the moving speed of the head 32 is slowed down, the recording position of the dots will be less likely to shift.

Therefore, by making the moving speed of the head 32 slower in the second ejection operation than in the first ejection operation, the deviation in the recording position of the dots is reduced even when performing the second ejection operation, and the nozzle 33 and the sheet The slope of the image due to the difference in distance from S can be reduced.

[Other variations]
Although the printer shown above is a monochrome printer, the printer of the present invention may be a printer that can selectively perform monochrome printing and color printing. This printer includes four mounting cases 36 and four sub-tanks 35 inside the housing 11. There are cases in which four cartridges storing black ink are installed in the four installation cases 36, and cases in which four cartridges storing each of cyan, magenta, yellow, and black inks are installed.

When the four cartridges are the first to fourth cartridges and the four subtanks 35 are the first to fourth subtanks, the nozzles 33 in the first nozzle row K1 are supplied from the first cartridge via the first subtank. Ink is ejected. Ink supplied from the second cartridge via the second sub-tank is ejected from the nozzles 33 in the second nozzle row K2. Ink supplied from the third cartridge via the third sub-tank is ejected from the nozzles 33 in the third nozzle row K3. Ink supplied from the fourth cartridge via the fourth sub-tank is ejected from the nozzles 33 in the fourth nozzle row K4.

The control unit 40 performs monochrome printing in which liquid of the same color is ejected from the nozzles 33 in the first to fourth nozzle rows K1 to K4, and prints from the nozzles 33 in the first to fourth nozzle rows K1 to K4 according to each nozzle row. Color printing is performed by ejecting liquid of a different color. Note that monochrome printing is an example of the first operation. Color printing is an example of the second operation.

According to this printer, a monochrome image is recorded by ejecting liquid of the same color from the nozzles 33 in the four nozzle rows K1 to K4, and a liquid of four colors is ejected from the nozzles 33 in the four nozzle rows K1 to K4. It is possible to selectively perform the operation of ejecting and recording a color image.

Further, although the printer shown above is equipped with a moving mechanism including a pair of transport rollers 22, a pair of ejection rollers 24, and a carriage 31, the printer of the present invention is equipped with a head and performs main scanning on a sheet. The moving mechanism may include a carriage that moves in a direction intersecting the main scanning direction and the main scanning direction.

5...First inclination direction (first direction)
6...Second inclination direction (second direction)
8...Back and forth direction (conveying direction)
9...Left and right direction (main scanning direction)
10... Printer (liquid ejection device)
22... Conveyance roller pair (moving mechanism)
24...Discharge roller pair (moving mechanism)
31... Carriage (moving mechanism)
32...Head 33...Nozzle 40...Control unit

Claims (10)

a head having multiple nozzles that eject liquid;
a moving mechanism that moves the head relative to the ejection target medium in a main scanning direction and a conveyance direction intersecting the main scanning direction;
comprising a control unit;
The head includes a first nozzle row in which a plurality of nozzles are lined up in a predetermined direction,
The control unit moves the head in a first direction along the main scanning direction to perform a first ejection operation of ejecting liquid from the nozzle, and moves the head in a first direction opposite to the first direction. It is possible to perform unidirectional recording of recording an image on the ejection target medium without performing a second ejection operation of moving in two directions and ejecting liquid from the nozzle,
The first nozzle row is arranged such that one end of the first nozzle row, which has a smaller distance from the nozzle to the medium to be ejected, is located closer to the terminal end in the first direction than the other end. A liquid ejection device that is arranged at an angle with respect to the direction. In the head, the first nozzle row and the second nozzle row are arranged in a first direction,
In the first nozzle row and the second nozzle row, a plurality of nozzles are arranged in a second direction intersecting the first direction,
The first nozzle row and the second nozzle row are configured such that the nozzles in the second nozzle row are located between the nozzles in the first nozzle row and the nozzles adjacent to the nozzles in the transport direction. , are arranged at an angle with respect to the conveyance direction,
The second nozzle row, together with the first nozzle row, has one end of the first nozzle row whose distance from the nozzle to the medium to be ejected is smaller than the other end in the first direction. 2. The liquid ejecting device according to claim 1, wherein the liquid ejecting device is arranged obliquely with respect to the transport direction so that the liquid ejecting device is located at an angle with respect to the conveyance direction. 2. The control unit is capable of selectively performing the unidirectional recording and the bidirectional recording in which an image is recorded on the ejection target medium in the first ejection operation and the second ejection operation. 2. The liquid ejection device according to 2. 4. The liquid ejecting apparatus according to claim 3, wherein the control section shifts the output timing of the ejection control signal of the nozzle by a larger amount in the second ejecting operation than in the first ejecting operation. 4. The liquid ejection apparatus according to claim 3, wherein the control section causes a delay amount of the ejection control signal for the nozzle to be larger in the second ejection operation than in the first ejection operation. 4. The liquid ejection apparatus according to claim 3, wherein the control section shifts the output timing of the ejection control signal of the nozzle based on the ejection position of the previous ejection operation when performing the bidirectional recording. In the second ejection operation, the control unit sets a delay amount of the ejection control signal of the nozzle to a different amount for a nozzle on one end side and a nozzle on the other end side in each nozzle row included in the head. The liquid ejection device according to claim 3. 4. The liquid ejecting apparatus according to claim 3, wherein the control section moves the head at a slower moving speed in the second ejecting operation than in the first ejecting operation. The nozzles in the first nozzle row are arranged at intervals in the second direction to form dots at a first resolution,
The nozzles in the second nozzle row are arranged in the second direction at intervals for forming dots at the first resolution,
3. The liquid ejecting device according to claim 2, wherein the nozzles in the first nozzle row and the nozzles in the second nozzle row form dots in the transport direction at a resolution twice the first resolution. In the head, a third nozzle row and a fourth nozzle row are arranged in the first direction together with the first nozzle row and the second nozzle row,
In the third nozzle row and the fourth nozzle row, a plurality of nozzles are arranged in the second direction,
The control unit performs a first operation of ejecting liquid of the same color from the nozzles in the first to fourth nozzle rows, and a liquid of a color corresponding to each nozzle row from the nozzles in the first to fourth nozzle rows. The liquid ejecting device according to claim 2, wherein the second operation of ejecting is selectively performed.

Images