Printing apparatus and printing method

Abstract

This invention provides a printing apparatus and a printing method. It appropriately prevents printing quality problems caused by the influence of a pressure adjustment mechanism. A printing apparatus that performs inkjet printing includes an inkjet head and an ink supply system (108). The ink supply system (108) has a pressure damper (204) as a pressure adjustment mechanism, a flow path (202) as a container-side flow path, and a connecting member (206) having the flow path (302). The flow path (302) serves as an inkjet head-side flow path supplying ink from the pressure damper (204) to the inkjet head. The pressure damper (204) supplies ink, at a pressure adjusted to a predetermined range lower than atmospheric pressure, from an output port (418) serving as the outlet of the pressure adjustment mechanism, to the flow path (302). At least a portion of the flow path cross-sectional area of ​​the flow path (302) at the connecting member (206) is larger than the flow path cross-sectional area of ​​the output port (418).

Description

Technical Field

[0001] This invention relates to a printing apparatus and a printing method. Background Technology

[0002] In recent years, inkjet printers, which use inkjet heads for printing, have been widely used. In addition, regarding the conventional structure for adjusting the pressure of the ink supplied to the inkjet head (ink supply pressure), it is known to have a structure that adjusts the ink supply pressure to a negative pressure lower than atmospheric pressure (for example, see Patent Document 1).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2012-232595 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] The inventors of this application have discovered that when ink is supplied to the inkjet head at a negative ink supply pressure, print quality can sometimes be problematic due to the influence of the pressure adjustment mechanism that adjusts the ink supply pressure. Therefore, the object of this invention is to provide a printing apparatus and printing method that can solve the above-mentioned problems.

[0008] Solution for solving the problem

[0009] The inventors of this application have conducted various experiments regarding a structure that supplies ink to the inkjet head using an ink supply pressure adjusted to negative pressure. Furthermore, they discovered that, for example, when printing at high speeds, print quality problems sometimes arise due to the influence of the pressure adjustment mechanism that adjusts the ink supply pressure. More specifically, when printing with an inkjet head, the amount of ink required by the inkjet head typically changes during the printing process. Therefore, for example, when printing at high speeds, the change in the amount of ink exiting the pressure adjustment mechanism sometimes cannot keep up with the change in the amount of ink required by the inkjet head. This, in turn, results in print quality problems. More specifically, in this case, for example, it is considered that because the ink supply rate from the ink supply system to the inkjet head cannot keep up with the ink consumption rate, the ink chambers, etc., accumulated in the inkjet head become empty, leading to print quality problems.

[0010] Regarding this point, it was previously not recognized that such a cause could lead to print quality problems. However, the inventors of this application, through various experiments, discovered that such a problem could arise due to the influence of the pressure adjustment mechanism. Furthermore, through in-depth research, the inventors found that by accumulating a certain amount of ink in the ink flow path from the pressure adjustment mechanism to the inkjet head, such a problem can be appropriately prevented. Additionally, as a structural design for this purpose, for example, an ink flow path is formed in the connecting member (the member connecting the pressure adjustment mechanism and the inkjet head), and this flow path is at least partially thicker than the outlet of the pressure adjustment mechanism. Moreover, through further experiments, it was confirmed that such a structure can appropriately prevent the aforementioned problem.

[0011] Furthermore, through further in-depth research, the inventors of this application discovered the features required to achieve such an effect, thus completing this invention. To address the aforementioned issues, the present invention provides a printing apparatus that performs inkjet printing. The printing apparatus includes: an inkjet head that ejects ink; and an ink supply system that supplies ink to the inkjet head from an ink container on the outside of the inkjet head. The ink supply system includes: a pressure adjusting mechanism for adjusting the pressure of the ink supplied to the inkjet head; a container-side flow path for supplying ink from the ink container to the pressure adjusting mechanism; and a connecting member for connecting the pressure adjusting mechanism and the inkjet head. This connecting member forms an inkjet head-side flow path, which serves as the flow path for supplying ink from the pressure adjusting mechanism to the inkjet head. The pressure adjusting mechanism supplies ink, adjusted to a pressure within a predetermined range lower than atmospheric pressure, from an outlet connected to the inkjet head-side flow path to the inkjet head-side flow path. At least a portion of the cross-sectional area of ​​the inkjet head-side flow path at the connecting member is larger than the cross-sectional area of ​​the outlet of the pressure adjusting mechanism.

[0012] With this configuration, by using an inkjet head-side flow path whose flow path area is at least partially larger than the cross-sectional area of ​​the flow path at the pressure adjustment mechanism outlet, ink can be accumulated sufficiently relative to the flow rate of ink exiting the pressure adjustment mechanism outlet, for example, at a position closer to the inkjet head than the pressure adjustment mechanism. Furthermore, this allows for more appropriate ink supply to the inkjet head, for example, when the amount of ink required by the inkjet head changes. Therefore, with this configuration, for example, it is possible to appropriately prevent print quality problems caused by the pressure adjustment mechanism. Furthermore, this allows for more appropriate high-quality printing, for example.

[0013] In this structure, the inkjet head side flow path is, for example, considered to use a flow path having at least one bend that changes the direction of ink flow. In this case, the inkjet head side flow path has, for example, a first flow path section that supplies ink upstream of the bend located at the outlet closest to the inkjet head in the inkjet head side flow path; and a second flow path section that supplies ink closer to the inkjet head than the first flow path section. Furthermore, the second flow path section is, for example, a straight flow path connected to the ink inlet of the inkjet head, supplying ink in a straight direction to the inkjet head side outlet in the inkjet head side flow path. Moreover, in this case, at least a portion of the cross-sectional area of ​​the second flow path section is considered to be larger than the cross-sectional area of ​​the pressure adjustment mechanism outlet and larger than the cross-sectional area of ​​the first flow path section. With this configuration, ink can be appropriately accumulated in the inkjet head side flow path, for example. In addition, by increasing the flow path area of ​​the portion of the ink supply that flows in a straight line to the inkjet head, for example, when the amount of ink required by the inkjet head changes, the required amount of ink can be supplied to the inkjet head quickly and appropriately.

[0014] Furthermore, in this structure, the printing device also includes, for example, a main scan drive unit. Regarding the main scan drive unit, it can be considered, for example, a drive unit that causes the inkjet head to perform a main scan operation while ejecting ink relative to the ink ejection target in a predetermined main scan direction. Additionally, the inkjet head may have, for example, four or more nozzle rows arranged in a manner where the positions of multiple nozzles in a nozzle row direction orthogonal to the main scan direction are different. In this case, each nozzle row at the inkjet head ejects ink of the same color supplied by the pressure adjustment mechanism via the inkjet head side flow path, and is arranged in a manner where the positions of the nozzles in the main scan direction are different.

[0015] In such cases, for example, among the multiple nozzle rows in an inkjet head that receive ink supply from a shared pressure adjustment mechanism, the number of nozzle rows simultaneously ejecting ink may change depending on the timing of the main scanning operation. Furthermore, in this case, because the number of nozzle rows simultaneously ejecting ink changes, the amount of ink required by the inkjet head also changes. Additionally, in this case, since the number of nozzle rows may be as many as four or more, the number of nozzle rows simultaneously ejecting ink can vary in various ways. Furthermore, the possibility that the change in the required amount of ink due to a change of only one nozzle row simultaneously ejecting ink is also considered. Moreover, in this case, the pressure adjustment mechanism needs to ensure that whenever the number of nozzle rows simultaneously ejecting ink in the inkjet head changes, the amount of ink exiting the pressure adjustment mechanism varies in such a way that the difference in ink amount at each stage is small, and the amount of ink varies in multiple stages corresponding to the number of nozzle rows.

[0016] However, in this case, for example, if the relative movement speed of the inkjet head is increased during the main scanning operation, it is easy for the change in the amount of ink exiting the pressure adjustment mechanism to lag behind the change in the number of nozzles simultaneously ejecting ink. Furthermore, this can result in print quality issues. Additionally, in this case, for example, if the main scanning operation is performed in a way that changes the amount of ink exiting the pressure adjustment mechanism in a timely manner, the relative movement speed of the inkjet head slows down, thereby reducing the printing speed. In contrast, with the configuration described above, for example, even if the change in the amount of ink exiting the pressure adjustment mechanism lags behind the change in the number of nozzles simultaneously ejecting ink, ink can be supplied appropriately to each nozzle of the inkjet head. Furthermore, this allows for, for example, higher-speed, higher-quality printing.

[0017] Furthermore, for example, in the case of full-page printing, it is easy for the amount of ink exiting from the pressure adjustment mechanism to become less than the change in the number of nozzles simultaneously ejecting ink near the end of the main scanning direction of the area being printed. In contrast, with the configuration described above, high-quality printing can be achieved even near the end of the main scanning direction of the area being printed. More specifically, regarding full-page printing, this can be considered as the operation of ejecting ink from a single nozzle at the inkjet head at all ejection positions set according to the printing resolution. In this case, near the end of the main scanning direction of the area being printed, the number of nozzles simultaneously ejecting ink changes along with the relative movement of the inkjet head in the main scanning direction during the main scanning operation. Moreover, in this case, the area where the number of nozzles simultaneously ejecting ink changes can be considered, for example, a nozzle number variation region. Furthermore, the portion of the area outside the nozzle number variation region in the area being printed can be considered, for example, a nozzle number constant region. Furthermore, in this case, during the main scanning operation, the main scanning drive unit can supply ink to the entire nozzle array at the inkjet head via the pressure adjustment mechanism in the region where the number of nozzle arrays is constant, and in the region where the number of nozzle arrays changes on at least one side of the main scanning direction, the inkjet head moves relative to the main scanning direction because the change in the amount of ink exiting from the pressure adjustment mechanism cannot keep up with the change in the number of nozzle arrays that eject ink.

[0018] With this configuration, for example, the relative speed of the inkjet head during the main scanning operation can be appropriately increased, thus enabling high-speed printing. Furthermore, by using an inkjet head-side flow path whose flow path area is at least partially larger than the flow path cross-sectional area of ​​the pressure adjustment mechanism outlet, ink supply to each nozzle of the inkjet head can be appropriately adjusted, for example, even when the change in the amount of ink exiting the pressure adjustment mechanism outlet cannot keep up with the change in the number of ink-ejecting nozzle arrays. Therefore, with this configuration, for example, high-speed and high-quality printing can be appropriately performed.

[0019] Furthermore, in this structure, the inkjet head-side flow path of the connecting member can also function as a buffer for ink flow rate. More specifically, in this case, by making at least a portion of the flow path cross-sectional area of ​​the inkjet head-side flow path at the connecting member larger than the flow path cross-sectional area of ​​the pressure regulating mechanism outlet, the inkjet head-side flow path of the connecting member can function as a buffer for adjusting the ink flow rate between the pressure regulating mechanism outlet and the inkjet head. Additionally, in this case, the inkjet head-side flow path supplies the amount of ink required for the ink-ejecting nozzle array to the nozzle array, for example, when the change in the amount of ink exiting the pressure regulating mechanism outlet cannot keep up with the change in the number of ink-ejecting nozzle arrays. With this configuration, for example, the ink supply to each nozzle of the inkjet head can be appropriately performed.

[0020] Furthermore, in this structure, the pressure adjustment mechanism includes, for example, an ink accumulation section, a pressure regulating section, and a valve. The ink accumulation section accumulates ink, for example, midway through the flow path within the adjustment mechanism. In this case, the flow path within the adjustment mechanism can be considered, for example, as a flow path for ink supplied from the ink container to flow towards the inkjet head within the pressure adjustment mechanism. Additionally, the ink accumulation section is, for example, an accumulation section with an opening. The pressure regulating section adjusts the pressure of the ink accumulated in the ink accumulation section to a pressure lower than atmospheric pressure. More specifically, the pressure regulating section includes, for example, a flexible membrane and a force-applying member. In this case, the flexible membrane covers the opening of the ink accumulation section, for example, with its side facing the atmosphere opposite to the ink accumulation section. Additionally, the force-applying member applies force to the flexible membrane, for example, in a direction away from the ink accumulation section. Moreover, the pressure regulating section, for example, uses the force-applying member to apply force to the flexible membrane, thereby adjusting the pressure of the ink accumulated in the ink accumulation section to a pressure lower than atmospheric pressure. Furthermore, the valve is, for example, disposed between the ink accumulation section and the inkjet head within the flow path of the adjustment mechanism. In this case, the valve opens and closes, for example, based on the pressure difference between the ink pressure on the inkjet head side of the flow path within the adjusting mechanism and the ink pressure in the ink reservoir, thereby allowing ink with a pressure adjusted to a predetermined range to flow toward the inkjet head. With this configuration, for example, the pressure of the ink supplied to the inkjet head can be appropriately adjusted using the pressure adjusting mechanism. As such a pressure adjusting mechanism, a known mechanical pressure damper, for example, can be preferably used.

[0021] Furthermore, regarding the relative movement speed of the inkjet head during the main scanning operation and the characteristics of the ink supply operation to the inkjet head via the connecting member, it can be considered, for example, by comparing it with the case where ink is supplied to the inkjet head from the pressure adjustment mechanism using a flow path whose flow path cross-sectional area is less than the flow path cross-sectional area of ​​the pressure adjustment mechanism outlet in all positions. More specifically, in this case, for example, a structure that uses a connecting member having an inkjet head-side flow path having a flow path cross-sectional area at least partially larger than the flow path cross-sectional area of ​​the pressure adjustment mechanism outlet can be defined as a first ink supply structure, and a structure that uses a flow path whose flow path cross-sectional area is less than the flow path cross-sectional area of ​​the pressure adjustment mechanism outlet in all positions as the flow path for supplying ink to the inkjet head from the pressure adjustment mechanism can be defined as a second ink supply structure, to consider the relative movement speed of the inkjet head during the main scanning operation and the characteristics of the ink supply operation to the inkjet head via the connecting member. Furthermore, in this case, for example, in the nozzle number variation region where the number of nozzles simultaneously ejecting ink gradually increases, the main scan drive unit moves the ink head relative to the main scan direction at a speed where, for example, when ink is supplied to the ink head using the second ink supply structure, the ink supplied to the nozzles to be ejected is insufficient for at least a portion of the time. Additionally, the connecting member supplies ink to the ink head using, for example, the first ink supply structure, so that, for example, in the nozzle number variation region where the number of nozzles simultaneously ejecting ink gradually increases, the connecting member supplies ink to the ink head in a manner that does not result in insufficient ink supply to the nozzles to be ejected. With this configuration, for example, the relative movement speed of the ink head during main scan operation can be appropriately increased, and the ink supply to the ink head can be appropriately performed. Furthermore, this enables, for example, appropriately high-speed and high-quality printing.

[0022] Furthermore, the features of the present invention can also be considered from different perspectives than those described above. In such cases, for example, the features of the present invention can be considered from the perspective that the inkjet head-side flow path of the connecting member functions as a buffer for ink flow. In addition, in this case, the present invention can be considered, for example, as follows: A printing apparatus that performs inkjet printing, characterized in that the printing apparatus comprises: an inkjet head that ejects ink in an inkjet manner; and an ink supply system that supplies ink to the inkjet head from an ink container on the outside of the inkjet head, the ink supply system comprising: a pressure adjusting mechanism for adjusting the pressure of the ink supplied to the inkjet head; a container-side flow path for supplying ink from the ink container to the pressure adjusting mechanism; and an inkjet head-side flow path for supplying ink from the pressure adjusting mechanism to the inkjet head. In the ink flow path of the inkjet head, the pressure adjustment mechanism supplies ink at a pressure adjusted to a predetermined range lower than atmospheric pressure from the outlet of the pressure adjustment mechanism, which is connected to the inkjet head side flow path, to the inkjet head side flow path. The inkjet head side flow path accumulates ink in the portion before the inkjet head, thus functioning as a buffer to adjust the ink flow rate between the outlet of the pressure adjustment mechanism and the inkjet head. It supplies the inkjet head with the required amount of ink when the change in the amount of ink exiting the outlet of the pressure adjustment mechanism cannot keep up with the change in the amount of ink required by the inkjet head. Furthermore, as a structure of the present invention, the use of printing methods having the same features as described above is also considered.

[0023] The effects of the invention

[0024] According to the present invention, for example, it is possible to appropriately prevent printing quality problems caused by the influence of the pressure adjustment mechanism. Attached Figure Description

[0025] Figure 1 This is a diagram illustrating a printing apparatus 100 according to one embodiment of the present invention. Figure 1 (a) represents an example of the structure of the main part of the printing device 100. Figure 1 (b) shows an example of the structure of the inkjet head 102 in the printing device 100.

[0026] Figure 2 This diagram illustrates the more specific structure of the ink supply system 108. Figure 2 (a) represents an example of the structure of ink supply system 108. Figure 2 (b) represents an example of the structure of the main part of the ink supply system 108. Figure 2 (c) represents an example of the structure of the flow path 302 at the connecting member 206.

[0027] Figure 3This is a diagram showing an example of the structure of the connecting member 206. Figure 3 (a) indicates the structure of the connecting member 206, which is different from that in this example. Figure 3 (b) represents an example of the structure of the connecting member 206 in this example.

[0028] Figure 4 This is a diagram showing an example of the specific structure of the pressure damper 204.

[0029] Figure 5 It is a diagram that explains in detail the actions involved in full-page printing. Figure 5 (a) represents an example of a full-page print area of ​​500. Figure 5 (b) represents an example of the change in the number of ejector nozzle rows caused by the movement of the inkjet head 102 during the main scanning action. Figure 5 (c) represents part of the results of an experiment conducted using multiple structures obtained by varying the connection method between the pressure damper 204 and the inkjet head 102.

[0030] Figure 6 This is a simplified diagram illustrating the flow rate of ink flowing in flow path 302. Figure 6 (a) is a diagram illustrating the flow rate of ink flowing in a flow path different from the flow path 302 in this example. Figure 6 (b) is a simplified example of the flow rate of ink flowing in flow path 302 in this example.

[0031] Figure 7 This is a diagram illustrating a modified example of the flow path 302 at the connecting member 206. Figure 7 of (a), Figure 7 (b) represents a variation of flow path 302.

[0032] Explanation of reference numerals in the attached figures

[0033] 100. Printing unit; 102. Inkjet head; 104. Tabletop; 106. Ink container; 108. Ink supply system; 110. Carriage; 112. Main scan drive unit; 114. Sub-scan drive unit; 120. Control unit; 122. Nozzle array; 152. Inlet; 202. Flow path; 204. Pressure damper; 206. Connecting member; 302. Flow path; 312. First flow path section; 314. Second flow path section. Flow path section; 322, Bending section; 402, Negative pressure chamber; 404, Pressure chamber; 406, Connecting flow path chamber; 408, Pressure regulating section; 410, Valve; 412, Spring; 414, Working rod; 416, Inlet; 418, Outlet; 422, Flexible membrane; 424, Pressure-bearing component; 426, Spring; 50, Medium; 500, Full-page printing area; 502, Non-end area; 504, End area. Detailed Implementation

[0034] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Figure 1 This is a diagram illustrating a printing apparatus 100 according to one embodiment of the present invention. Figure 1 (a) represents an example of the structure of the main part of the printing device 100. Figure 1 (b) shows an example of the structure of the inkjet head 102 in the printing apparatus 100. In this example, the printing apparatus 100 is an inkjet printer that prints on the medium 50 to be printed using an inkjet method, and includes multiple inkjet heads 102, a table 104, multiple ink containers 106, an ink supply system 108, a carriage 110, a main scan drive unit 112, a secondary scan drive unit 114, and a control unit 120. Except for the aspects described below, the printing apparatus 100 may have the same or identical features as known inkjet printers. For example, the printing apparatus 100, in addition to having Figure 1 In addition to the structure shown, it may also have the same or identical structure as a known inkjet printer.

[0035] Multiple inkjet heads 102 are ink ejection heads that eject ink in an inkjet manner, ejecting ink supplied from multiple ink containers 106 via an ink supply system 108 to the medium 50, which is the object of ink ejection. Furthermore, in this example, each inkjet head 102 ejects ink of a different color. More specifically, in this example, each inkjet head 102 ejects ink of a different color from the primary printing colors used in subtractive color mixing, such as yellow (Y), magenta (M), cyan (C), and black (K). Additionally, each inkjet head 102 has multiple nozzles from which ink is ejected according to the image being printed. More specifically, in this example, for example... Figure 1As shown in (b), each inkjet head 102 has multiple nozzle rows 122. In this case, the nozzle row 122 can be considered, for example, as a row of multiple nozzles arranged in a way that their positions are staggered in a predetermined nozzle row direction. More specifically, in this example, the nozzle row direction is orthogonal to the direction of movement of the inkjet head 102 during the main scanning operation, i.e., the main scanning direction (Y direction in the figure). The main scanning operation can be considered, for example, as an operation of moving relative to the medium 50 and ejecting ink in a predetermined main scanning direction. In this example, the multiple nozzles included in each nozzle row 122 are arranged in the nozzle row direction in a way that their positions are aligned in the main scanning direction. Moreover, the multiple nozzle rows 122 at one inkjet head 102 are arranged in the main scanning direction in a way that their positions are different from each other in the main scanning direction. In addition, at each inkjet head 102, the multiple nozzle rows 122 eject ink supplied from a certain ink container 106 by means of the ink supply system 108. In addition, the multiple nozzle rows 122 at one inkjet head 102 eject ink of the same color. In addition, in this example, each inkjet head 102 is an example of an inkjet head having more than 4 rows of nozzle rows 122, having 6 rows (6 nozzle rows) 122.

[0036] The platform 104 is a platform-shaped member that holds the medium 50 and faces it toward the plurality of inkjet heads 102. The plurality of ink containers 106 are containers that accumulate ink supplied to the plurality of inkjet heads 102 outside the inkjet heads 102. In this example, the plurality of ink containers 106 each accumulate ink of a different color, and the ink is supplied to a particular inkjet head 102 via the ink supply system 108. Ink bottles, ink cartridges, etc., can be used as ink containers 106, for example. The ink supply system 108 is a structure that includes ink supply paths from the plurality of ink containers 106 to the plurality of inkjet heads 102. In this example, the ink supply system 108 has a pressure damper, etc., and supplies ink with adjusted supply pressure to the inkjet head 102 using the pressure damper. A more specific structure of the ink supply system 108 will be described in more detail later. The carriage 110 is a holding member that holds the plurality of inkjet heads 102. In this example, the carriage 110 holds multiple inkjet heads 102 and a portion of the ink supply system 108. More specifically, in this example, the carriage 110 holds pressure dampers or the like in the ink supply system 108. With this configuration, pressure dampers or the like can be appropriately placed near the inkjet heads 102, for example.

[0037] The main scan drive unit 112 is a drive unit that enables the multiple inkjet heads 102 to perform main scan operations. In this example, the main scan drive unit 112 moves the multiple inkjet heads 102 held on the carriage 110 by moving the carriage 110 in the main scan direction, thereby enabling the multiple inkjet heads 102 to perform main scan operations. Furthermore, during the main scan operation, the main scan drive unit 112 causes each nozzle at each inkjet head 102 to eject ink to an ink ejection position selected according to the image to be printed. The sub-scan drive unit 114 is a drive unit that enables the multiple inkjet heads 102 to perform sub-scan operations. The sub-scan operation can be considered, for example, as an operation of moving relative to the medium 50 in a sub-scan direction (X direction in the figure) orthogonal to the main scan direction. In this example, the sub-scan drive unit 114 enables the multiple inkjet heads 102 to perform sub-scan operations by conveying the medium 50 in a transport direction parallel to the sub-scan direction. Furthermore, the sub-scan drive unit 114 performs sub-scan operations on the multiple inkjet heads 102 during the intervals of the main scan operation, thereby changing the range relative to the multiple inkjet heads 102 for the medium 50. The control unit 120 includes, for example, the CPU of the printing device 100, and controls the operation of each part of the printing device 100 according to a program (e.g., firmware) that controls the operation of the printing device 100. According to this example, for example, the operation of printing on the medium 50 can be performed appropriately.

[0038] Next, a more detailed description will be given of the specific structure of the ink supply system 108 in the printing apparatus 100. Figure 2 This diagram illustrates the more specific structure of the ink supply system 108. Figure 2 Figure (a) is an example of the structure of the ink supply system 108, showing an example of the structure for supplying ink from the ink container 106 to the inkjet head 102 by focusing on the path of supplying ink to one of the multiple inkjet heads 102 in the printing device 100. Figure 2 Figure (b) shows an example of the structure of the main part of the ink supply system 108, and an example of the structure of the pressure damper 204 and the connecting member 206 that constitute part of the ink supply system 108 is shown together with the inkjet head 102. Figure 2 (c) represents an example of the structure of the flow path 302 at the connecting member 206. In this example, the ink supply system 108 has a flow path 202, a pressure damper 204, and a connecting member 206 as a structure for supplying ink from the ink container 106 to an inkjet head 102.

[0039] Flow path 202 is the flow path for ink from ink container 106 to pressure damper 204. In this example, flow path 202 is an example of a container-side flow path, from ink container 106 to ink held in carriage 110 (see reference). Figure 1Ink is supplied to the pressure damper 204. In this case, the position of the end of the flow path 202 located on the pressure damper 204 side changes during the main scanning operation. Therefore, the flow path 202 can be, for example, considered as a flexible flow path that supplies ink to the pressure damper 204 that moves together with the inkjet head 102. As such a flow path 202, a flexible tube can preferably be used, for example.

[0040] Pressure damper 204 is an example of a pressure adjustment mechanism used to adjust the pressure of ink supplied to inkjet head 102. In this example, pressure damper 204 adjusts the ink received from ink container 106 via flow path 202 to a negative pressure within a specified range lower than atmospheric pressure. Furthermore, the pressure-adjusted ink is supplied to inkjet head 102 via connecting member 206. More specifically, in this example, for example... Figure 2 As shown in (b), regarding ink with a pressure adjusted to a specified negative pressure range, the pressure damper 204 supplies ink to the flow path 302 at the connecting member 206 via the ink outlet, i.e., the output port 418. In this case, the output port 418 of the pressure damper 204 is an example of the outlet of a pressure adjusting mechanism. Furthermore, in this example, the pressure damper 204 is a mechanical pressure damper. In this case, the pressure damper 204 may, for example, have the same or identical structure as a known mechanical pressure damper. More specifically, as the pressure damper 204, for example, it is preferable to use a structure similar to or the same as the pressure regulating valve disclosed in Japanese Patent Application Publication No. 2012-232595. A more specific structure of the pressure damper 204 will be described in more detail later.

[0041] The connecting member 206 connects the pressure damper 204 and the inkjet head 102. In this example, the connecting member 206 functions as a retaining member for the pressure damper 204, and is located near the inkjet head 102 and disposed on the carriage 110. In this case, the pressure damper 204 can be considered as being disposed on the carriage 110 together with the inkjet head 102 and the connecting member 206, for example, by being held by the connecting member 206. In addition, in this example, a flow path 302 for ink to flow from the pressure damper 204 to the inkjet head 102 is formed in the connecting member 206. The flow path 302 is an example of an inkjet head-side flow path where ink flows closer to the inkjet head 102 than the pressure damper 204. In this example, flow path 302 is a flow path for ink with a fixed path within the connecting member 206. One end is connected to the output port 418 of the pressure damper 204, and the other end is connected to the ink inlet 152 of the inkjet head 102, thereby allowing ink to flow from the pressure damper 204 to the inkjet head 102. For example, flow path 302 could be considered as having at least one bend that changes the direction of ink flow.

[0042] More specifically, in this example, for example, Figure 2 As shown in (c), the flow path 302 has multiple bends 322a and 322b. Furthermore, regarding the flow path 302 in this example, it could also be, for example, a flow path for ink with a first flow path portion 312 and a second flow path portion 314 as shown in the figure. In this case, the first flow path portion 312 could be, for example, a flow path supplying ink upstream of the bend portion 322b located at the outlet position closest to the inkjet head 102 in the flow path 302. In this example, the first flow path portion 312 is an ink flow path that bends at a position upstream of the bend portion 322b, separated by the bend portion 322a. The second flow path portion 314 could be, for example, a flow path supplying ink closer to the inkjet head 102 than the first flow path portion 312. In this example, the second flow path portion 314 is a straight flow path connected to the ink inlet 152 of the inkjet head 102. In this case, the second flow path 314 can be considered as a flow path through which ink flows in a straight line in a certain direction to the outlet of the inkjet head 102 in the flow path 302.

[0043] Furthermore, in this example, the second flow path 314 is a flow path with a larger cross-sectional area than the first flow path 312 and the output port 418 of the pressure damper 204 (a coarser flow path). More specifically, in this example, the first flow path 312 is a flow path with a cross-sectional area of ​​a predetermined value S1. In this case, the cross-sectional area of ​​the flow path can be considered, for example, the cross-sectional area of ​​the flow path on a plane orthogonal to the direction of ink flow. The cross-sectional area of ​​the flow path can also be considered, for example, the area representing the thickness of the flow path. In addition, in the case of a flow path with a bend in the middle, such as the first flow path 312, it is difficult to accurately consider the cross-sectional area of ​​the flow path at the location of the bend. Therefore, the case where the cross-sectional area of ​​the first flow path 312 is S1 can also be considered, for example, the case where the flow path area of ​​the straight portion of the first flow path 312 is S1. Furthermore, in this example, the cross-sectional area S1 of the first flow path section 312 is equal to the cross-sectional area of ​​the flow path of the output port 418 of the pressure damper 204. In this case, regarding the case where the cross-sectional areas of the flow paths are equal, for example, it can be considered that they are substantially equal within the allowable range of offsets, errors, etc., caused by connecting multiple flow paths. Furthermore, regarding the case where the cross-sectional areas of the flow paths are equal between the output port 418 and the first flow path section 312, for example, it can be considered that the cross-sectional area of ​​the first flow path section 312 is not intentionally designed to be different from the cross-sectional area of ​​the flow path of the output port 418 of the pressure damper 204, but rather matched with the cross-sectional area of ​​the flow path of the output port 418.

[0044] In contrast, in this example, the cross-sectional area of ​​the second flow path 314 is larger than the cross-sectional area S1 of the first flow path 312. More specifically, in this example, the cross-sectional area of ​​the second flow path 314 is a value S2 greater than S1. In this case, the cross-sectional area S2 of the second flow path 314 can also be considered to be larger than the cross-sectional area of ​​the output port 418 of the pressure damper 204. In addition, the second flow path 314 can also be considered to be a flow path that is thicker than the output port 418 and the first flow path 312. Regarding the structure in which the second flow path 314 is thicker than the first flow path 312, it can also be considered that the second flow path 314 functions as an ink accumulation section in the flow path 302.

[0045] Furthermore, regarding the structure of the flow path 302 in this example, it is also possible to consider an example where at least a portion of the flow path cross-sectional area of ​​the flow path 302 is larger than the flow path cross-sectional area of ​​the output port 418 of the pressure damper 204. In this case, the situation where at least a portion of the flow path cross-sectional area of ​​the flow path 302 is larger than the flow path cross-sectional area of ​​the output port 418 of the pressure damper 204 can be considered, for example, where at least a portion of the flow path cross-sectional area of ​​the flow path 302 is substantially larger than the flow path cross-sectional area of ​​the output port 418 of the pressure damper 204. Additionally, in practical applications, the situation where at least a portion of the flow path cross-sectional area of ​​the flow path 302 is larger than the flow path cross-sectional area of ​​the output port 418 of the pressure damper 204 can be considered, for example, where the flow path cross-sectional area of ​​at least a portion of the flow path 302 (e.g., the second flow path portion 314) is at least 1.1 times (preferably at least 1.2 times) the flow path cross-sectional area of ​​the output port 418 of the pressure damper 204.

[0046] Furthermore, regarding the characteristics of the flow path 302 at the connecting member 206 in this example, for example... Figure 3 As shown, a more specific and appropriate understanding can be achieved by comparing it with the connecting member 206, which has a structure different from this example. Figure 3 This is a diagram showing an example of the structure of the connecting member 206. Figure 3 (a) indicates a structure different from the connecting member 206 in this example. Figure 3 (b) represents an example of the structure of the connecting member 206 in this example. Hereinafter, for ease of explanation, Figure 3 The connecting member 206 shown in (a) is referred to as the conventional connecting member 206. Furthermore, regarding... Figure 3 (b), for example, can be considered as a more specific representation Figure 2 A diagram showing the structure of the connecting member 206.

[0047] like Figure 3As shown in (a), regarding the conventional connecting member 206, for example, it can be considered that the flow path cross-sectional area is constant throughout the entire flow path 302. Furthermore, in this case, this constant flow path cross-sectional area can be considered as an area matching the flow path cross-sectional area of ​​the output port of the pressure damper 204. In contrast, in Figure 3 In the connecting member 206 shown in (b) of this example, as explained above, the cross-sectional area of ​​the second flow path portion 314 in the flow path 302 is larger than the cross-sectional area of ​​the flow path of the output port of the pressure damper 204 and the first flow path portion 312. Furthermore, in this case, for example, it is possible to consider making the cross-sectional area of ​​the second flow path portion 314 in the flow path 302 larger than the cross-sectional area of ​​the flow path 302 at the conventional connecting member 206. Additionally, for example, an example of the structure of the flow path 302 in this example could be considered where at least a portion of the cross-sectional area of ​​the flow path is larger than the cross-sectional area of ​​the output port of the pressure damper 204. Furthermore, for example, another example of this structure could be considered where at least a portion of the cross-sectional area of ​​the second flow path portion 314 is larger than the cross-sectional area of ​​the flow path of the output port of the pressure damper 204.

[0048] Furthermore, in this case, since at least a portion of the flow path cross-sectional area of ​​the flow path 302 is increased in the connecting member 206 of this example, ink supply to the inkjet head 102 can be performed more appropriately, resulting in high-quality printing. More specifically, in this example, by increasing at least a portion of the flow path cross-sectional area of ​​the flow path 302 connecting the pressure damper 204 and the inkjet head 102, ink supply to the inkjet head 102 can be performed more appropriately, even if the change in the amount of ink exiting from the output port of the pressure damper 204 is delayed, for example, even if the amount of ink required by the inkjet head 102 changes. Additionally, in this case, such an effect can be obtained more appropriately by increasing the flow path cross-sectional area of ​​the second flow path portion 314 in the flow path 302. Therefore, the technical significance related to the structure of the connecting member 206 of this example will be explained in detail below. Furthermore, as explained in detail below, the structure of the connecting member 206 of this example is related to the case where the pressure damper 204 is used. Therefore, the specific structure of the pressure damper 204 will be described first.

[0049] Figure 4Here is an example of the specific structure of the pressure damper 204. As explained above, the pressure damper 204 is a mechanical pressure damper. In this case, a mechanical pressure damper can be considered, for example, a pressure regulating mechanism that adjusts pressure using only passive components. Passive components can be considered, for example, components that do not require the supply of energy such as electricity. A mechanical pressure damper can also be considered, for example, a pressure regulating mechanism that adjusts pressure without using a pump that receives the supply of energy such as electricity. In this example, the pressure damper 204 includes a negative pressure chamber 402, a pressure chamber 404, a connecting flow path chamber 406, a pressure regulating part 408, a valve 410, a spring 412, a working rod 414, an inlet 416, and an outlet 418.

[0050] The negative pressure chamber 402, the pressure chamber 404, and the connecting flow path chamber 406 are structures that form part of the ink flow path within the pressure damper 204, i.e., the flow path within the adjustment mechanism. In this case, the flow path within the adjustment mechanism can be considered, for example, as being supplied from the ink container 106 (see reference). Figure 1 The supplied ink is directed toward the inkjet head 102 in the pressure damper 204 (see reference). Figure 1 The flow path of the flowing ink, etc. Furthermore, in this example, regarding the case where the ink supply flows towards the inkjet head 102 within the adjustment mechanism, it can be considered, for example, relative to the connecting member 206 (see reference). Figure 2 In the case of ink being output from the output port 418, etc. Furthermore, in these structures, the negative pressure chamber 402 is an example of an ink storage section that accumulates ink midway through the flow path within the adjustment mechanism. In the flow path within the adjustment mechanism, ink supplied from the ink container 106 via the input port 416 is stored upstream of the pressure chamber 404 and the connecting flow path chamber 406 in the direction of ink flow. In this example, the negative pressure chamber 402 is a storage section with an opening, and ink is stored with the opening covered by the flexible membrane 422 of the pressure regulating section 408. Thus, the negative pressure chamber 402 stores ink whose pressure has been adjusted by the pressure regulating section 408. Additionally, the negative pressure chamber 402 connects to the ink flow path 202 (see reference 416) via the input port 416. Figure 2 The negative pressure chamber 402 is connected to the ink supply system 108, thereby accumulating ink supplied by the ink supply system 108. Moreover, in this example, the negative pressure chamber 402 has an opening that serves as a flow path for ink on the side opposite to the opening covered by the flexible membrane 422, and is connected to the connecting flow path chamber 406 through this opening.

[0051] Pressure chamber 404 is an ink accumulation section located downstream of negative pressure chamber 402 and connecting flow path chamber 406 in the ink flow direction within the flow path of the adjustment mechanism. In this example, pressure chamber 404 accumulates ink before output port 418 and is connected to inkjet head 102 via output port 418 and connecting member 206. This ensures that the ink pressure in pressure chamber 404 is balanced with the ink pressure within inkjet head 102. In this case, the ink pressure within inkjet head 102 refers, for example, to the ink pressure in the ink chamber accumulating ink before the nozzle at inkjet head 102. Furthermore, in this example, pressure chamber 404 is connected to connecting flow path chamber 406 via an opening, and thus connected to negative pressure chamber 402 via this opening and connecting flow path chamber 406. A valve 410 is provided at the opening between pressure chamber 404 and connecting flow path chamber 406. The connecting flow path chamber 406 is a space that serves as a flow path connecting the negative pressure chamber 402 and the pressure chamber 404. In this example, the connecting flow path chamber 406 also houses a working rod 414 that is linked to the valve 410.

[0052] The pressure regulating unit 408 is a structure used to adjust the pressure of ink accumulated in the negative pressure chamber 402 to a predetermined negative pressure lower than atmospheric pressure. In this example, the pressure regulating unit 408 includes a flexible membrane 422, a pressure-bearing member 424, and a spring 426. The flexible membrane 422 is a flexible membrane that, as described above, covers the opening of the negative pressure chamber 402. More specifically, in this example, the flexible membrane 422 is an airtight film that covers the opening of the negative pressure chamber 402 in a state where the side opposite to the negative pressure chamber 402 is exposed to the atmosphere. For example, a resin film can preferably be used as the flexible membrane 422. The pressure-bearing member 424 is a member that bears the force on the flexible membrane 422 from its surroundings, and is integrally joined to the surface of the flexible membrane 422 facing the negative pressure chamber 402 in such a way that it bears the force from the spring 426 that pushes the flexible membrane 422 outward. In this case, the pressure-bearing member 424 can be considered, for example, to bear a force corresponding to atmospheric pressure across the flexible membrane 422, and in the opposite direction to this force, to bear the force of the spring 426 and a force corresponding to the pressure of the ink brought by the ink in the negative pressure chamber 402. Furthermore, in this example, the pressure-bearing member 424 has a rod-shaped pressure-transmitting part that passes through an opening between the negative pressure chamber 402 and the connecting flow path chamber 406. By engaging the pressure-transmitting part with the working rod 414 through this opening, the force borne by the pressure-bearing member 424 from its surroundings is transmitted to the working rod 414. The spring 426 is an example of a force-applying component; by applying a force to the pressure-bearing member 424 in a direction that pushes the flexible membrane 422 outward, a force is applied to the flexible membrane 422 in a direction away from the negative pressure chamber 402.

[0053] In this configuration, as described above, the outer surface of the flexible membrane 422 bears a force corresponding to atmospheric pressure. Conversely, the inner surface of the flexible membrane 422 bears the force of the spring 426 via the pressure-bearing member 424 and a force corresponding to the pressure of the ink within the negative pressure chamber 402. Furthermore, in this case, the forces borne by the outer and inner surfaces of the flexible membrane 422 are balanced, thus the pressure of the ink within the negative pressure chamber 402 can be, for example, considered as a predetermined negative pressure determined based on the force of the spring 426. Additionally, regarding the pressure regulating section 408, for example, it can be considered as adjusting the pressure of the ink accumulated in the negative pressure chamber 402 to a pressure lower than atmospheric pressure by applying force to the flexible membrane 422 using the spring 426.

[0054] Valve 410 is an opening and closing component that opens and closes the opening between pressure chamber 404 and connecting flow path chamber 406. Valve 410 can also be, for example, disposed in the flow path within the adjustment mechanism between negative pressure chamber 402 and inkjet head 102. In this example, valve 410 is a valve that closes by moving in the direction from pressure chamber 404 to connecting flow path chamber 406, and opens by moving in the opposite direction, receiving a force from working lever 414 on the connecting flow path chamber 406 side and a force from spring 412 on the pressure chamber 404 side. In this case, valve 410 can also be, for example, receiving a force corresponding to the pressure of ink accumulated in connecting flow path chamber 406 on the connecting flow path chamber 406 side, and a force corresponding to the pressure of ink accumulated in pressure chamber 404 on the pressure chamber 404 side. In this example, spring 412 is disposed within pressure chamber 404 and applies force to valve 410 in the direction of closing valve 410. Conversely, working rod 414 applies a force to valve 410 from the side of connecting flow path chamber 406 in the direction of opening valve 410. Furthermore, according to... Figure 4 As can be understood from the structure illustrated in the diagram, the working rod 414 applies a force to the valve 410 corresponding to the force transmitted by the self-supporting member 424. More specifically, in this example, the working rod 414 is a member having an arm that swings relative to a pivot point on one side and the other side. The force transmitted by the self-supporting member 424 is varied according to a ratio determined by the lengths of the arms on one and the other sides and applied to the valve 410. Furthermore, the working rod 414 thus applies a force to the valve 410 corresponding to the pressure of the ink that has become negatively pressurized within the negative pressure chamber 402.

[0055] Furthermore, as explained above, in this example, the ink pressure in pressure chamber 404 is balanced with the ink pressure in inkjet head 102. Therefore, on the pressure chamber 404 side, valve 410 is subjected to a force corresponding to the ink pressure in inkjet head 102 and the force of spring 412. Moreover, in this case, when the ink pressure in inkjet head 102 is higher than a predetermined pressure, the force in the direction of closing valve 410 is dominant, and valve 410 is closed. In addition, for example, when ink is consumed at inkjet head 102 and the ink pressure in inkjet head 102 decreases, the force in the direction of closing valve 410 weakens, and the force in the direction of opening valve 410 is dominant, and valve 410 opens. As a result, ink adjusted to negative pressure in negative pressure chamber 402 flows into pressure chamber 404 via connecting flow path chamber 406. Moreover, the ink flowing into pressure chamber 404 is supplied to inkjet head 102 via output port 418 and connecting member 206. Furthermore, when a sufficient amount of ink is supplied to the inkjet head 102 and the pressure of the ink within the inkjet head 102 increases, the valve 410 closes, stopping the supply of ink to the inkjet head 102. In this case, the valve 410 can be opened and closed, for example, based on the pressure difference between the ink pressure on the inkjet head 102 side of the flow path within the adjustment mechanism and the ink pressure in the negative pressure chamber 402. Additionally, the valve 410 can be designed to allow ink with a pressure adjusted to a predetermined range to flow towards the inkjet head 102 using this opening and closing action.

[0056] Additionally, inlet 416 is the ink inlet for receiving ink supplied from ink container 106. Outlet 418 is the ink outlet for discharging ink toward connecting member 206. Furthermore, as can be understood from the above description, in this example, outlet 418 is connected to pressure chamber 404, discharging ink supplied from pressure chamber 404 toward connecting member 206. According to this example, for example, the pressure of the ink supplied to inkjet head 102 can be appropriately adjusted using pressure damper 204. Furthermore, this allows ink to be appropriately supplied to inkjet head 102 at a pressure adjusted to a predetermined negative pressure range lower than atmospheric pressure.

[0057] Next, the technical significance related to the structure of the connecting member 206 in this example will be explained in detail. As described above, in this example, by using the pressure damper 204, the pressure of the ink supplied to the inkjet head 102 can be adjusted. Furthermore, in this case, by using the mechanical pressure damper 204, miniaturization and cost reduction of the device can also be achieved. However, according to the printing device 100 (see reference...) Figure 1 The structure and operation of the device may also cause printing quality problems due to the use of pressure damper 204.

[0058] Regarding this, the inventors of this application discovered the following: When printing using conventional structures, when printing images such as barcodes (hereinafter referred to as barcode-like images) that are repeatedly arranged with a specified width (e.g., line width less than 2 mm) of vertical lines extending along the main scanning direction and leaving a specified blank space (e.g., blank space less than 2 mm), unexpected ink splatter sometimes occurs, affecting the print quality. Furthermore, it was discovered that in the case of so-called full-page printing, unexpected stripes sometimes appear near the end of the area to be filled, at the start and end of the drawing, affecting the print quality. In addition, various experiments confirmed that while there is a certain degree of deviation, it is a phenomenon independent of the type of ink (e.g., solvent ink, water-based ink, UV ink, etc.), and does not occur when the movement speed (scanning speed) of the inkjet head 102 during the main scanning operation is sufficiently slow, or when the number of print passes is sufficiently high. However, when the scanning speed is slowed down and the number of passes is increased, the printing speed decreases significantly. In contrast, in this example, by using the connecting member 206 of the structure described above, high-quality printing can be achieved more appropriately, even when printing at a speed that would cause problems with conventional structures. Furthermore, this will be explained in detail below with regard to the operation in the case of full-page printing.

[0059] Figure 5 It is a diagram that explains in detail the actions involved in full-page printing. Figure 5 (a) represents an example of a full-page printing area 500, where ink is ejected from the medium during full-page printing. In this case, full-page printing can be considered, for example, as the action of ejecting ink from a single nozzle at the printhead 102 at all ejection positions set according to the printing resolution. Furthermore, full-page printing can also be considered, for example, as the action of ejecting ink from a single nozzle of a plurality of nozzle rows at one printhead 102 at ejection positions within the full-page printing area 500. Regarding the case of ejecting ink from a nozzle to an ejection position, for example, it can be considered as ejecting ink at the designed ejection position in a manner that forms ink dots of a predetermined size. Additionally, full-page printing can also be considered as setting the printing density using a single color of ink to a preset density of 100%.

[0060] Furthermore, as explained above, in this example, the inkjet head 102 has six rows of nozzles. In this case, the six rows of nozzles at one inkjet head 102 can be considered as a row of nozzles that supply ink from the outside of the inkjet head 102 using a common path. Additionally, the six rows of nozzles at one inkjet head 102 can also be considered, for example, as a row of nozzles that supply ink via a flow path 302 in the connecting member 206 (see reference). Figure 2 Self-pressure damper 204 (reference) Figure 2 The nozzle array supplies ink of the same color and ejects it. Furthermore, in this case, during full-page printing, the main scan drive unit 112 (see reference 112)... Figure 1 Basically, the inkjet head 102 moves in the main scanning direction while simultaneously ejecting ink from all nozzle columns at one inkjet head 102. However, at the start and end times of drawing near the ends of the filled area in full-page printing, the main scanning drive unit 112 ejects ink only from a portion of the nozzle columns at the inkjet head 102. Therefore, the full-page printing area 500, as shown in the figure, can be considered as the area including the non-end area 502 and the end area 504.

[0061] The non-end region 502 is the area in the full-page printing area 500 excluding the ends in the main scanning direction. In the illustrated structure, the non-end region 502 can also be considered as the area in the full-page printing area 500 excluding the end region 504, etc. In this example, the non-end region 502 is the area depicted by ink ejected from all nozzle rows of one inkjet head 102. In this case, the non-end region 502 can be considered, for example, as an example of a region where the number of nozzle rows ejecting ink simultaneously during the main scanning operation remains constant. The number of ejected nozzle rows can be considered, for example, as the number of nozzle rows ejecting ink simultaneously in one inkjet head 102 that ejects ink during the full-page printing operation, etc. In this example, the number of ejected nozzle rows can be considered, for example, as the number of nozzle rows that simultaneously eject ink from among the multiple nozzle rows in one inkjet head 102 that receive ink supply from the shared pressure damper 204, etc. Furthermore, the end region 504 is the region corresponding to the start or completion of drawing in full-page printing. The full-page printing area 500 has end regions 504 on both sides in the main scanning direction. Additionally, during full-page printing, near the ends of the full-page printing area 500 in the main scanning direction, the number of nozzle rows changes as the inkjet head 102 moves in the main scanning direction during the main scanning operation. Moreover, in this example, such a region near the ends is called the end region 504. In this case, the end region 504 can be considered, for example, as an example of a nozzle row number variation region where the number of nozzle rows changes.

[0062] Additionally, in this example, the number of nozzle rows is, for example, as follows: Figure 5 The changes are shown in (b). Figure 5 (b) illustrates an example of the change in the number of nozzle rows caused by the movement of the inkjet head 102 during the main scanning operation. As shown, in the case of full-page printing, the number of nozzle rows gradually increases in the end region 504 on the drawing start side. Furthermore, in the non-end region 502, the number of nozzle rows remains constant. Moreover, in the end region 504 on the drawing end side, the number of nozzle rows gradually decreases. Thus, in the case of full-page printing, in the end region 504, it can be considered that the number of nozzle rows changes according to the time of the main scanning operation.

[0063] Furthermore, in order to perform full-page printing appropriately, the main scan operation is performed at least under the condition that ink required to supply the number of nozzle rows in the non-end area 502 to the inkjet head 102. Moreover, in this case, the amount of ink that can be supplied to the inkjet head 102 in the non-end area 502 can be determined, for example, based on the ink supply capability of the pressure damper 204. Furthermore, the amount of ink required by the inkjet head 102 during the main scan operation can be considered, for example, the ink consumption at the inkjet head 102 per unit time. Moreover, the ink consumption at the inkjet head 102 per unit time can be considered, for example, that the faster the inkjet head 102 moves during the main scan operation, the greater the consumption. Therefore, the moving speed of the inkjet head 102 during the main scan operation needs to be determined by at least considering the amount of ink required by the inkjet head 102 in the non-end area 502 and the ink supply capability of the pressure damper 204. Furthermore, in this case, during the main scan operation, the main scan drive unit 112 (refer to...) Figure 1 The inkjet head 102 is moved at a rate at which ink is supplied from the pressure damper 204 to the entire nozzle array at the non-end region 502 relative to the inkjet head 102 when performing full-page printing.

[0064] However, as described above, during full-page printing, the number of nozzle rows gradually changes in the non-end region 502. Furthermore, in this case, the amount of ink required by the inkjet head 102 also gradually changes with the number of nozzle rows. In contrast, as can be understood from the structure of the pressure damper 204 described above, for the pressure damper 204 in this example, the accompanying valve 410 (see reference...) Figure 4 The mechanical actions generated by the opening and closing of the output port 418 (refer to) cause the output port 418 to... Figure 4The amount of ink output changes. Furthermore, in this case, if the amount of ink required by the inkjet head 102 changes rapidly, it is considered that even if the ink supply capacity of the pressure damper 204 is sufficient, the amount of ink output from the pressure damper 204 may not have enough time to change. In this case, regarding the situation where the amount of ink output from the pressure damper 204 cannot change in time, for example, it can be considered that due to the output delay of the pressure damper 204 relative to the change in the amount of ink required by the inkjet head 102, the print quality is reduced. Additionally, regarding this point, for example... Figure 5 As shown in (c), the inventors of this application conducted various experiments using multiple structures obtained by varying the connection method between the pressure damper 204 and the inkjet head 102. Furthermore, regarding the splattering problem that occurred when printing barcode-like images as described above, and the striping problem that occurred when performing full-page printing, it was confirmed that the reduction in print quality was related to the insufficient change in the amount of ink exiting from the pressure damper 204.

[0065] Figure 5 (c) represents a portion of the results of an experiment conducted using multiple structures obtained by varying the connection method between the pressure damper 204 and the inkjet head 102. In the structures shown in the figure, this example uses... Figure 2 and Figure 3 The structure described in (b) uses a connecting member 206 to connect the pressure damper 204 and the inkjet head 102. Regarding the structure in this example, it is also possible to consider a structure in which the flow path 302 at the connecting member 206 is locally larger than the output port 418 of the pressure damper 204. Furthermore, in the structure shown in the figure, the conventional structure refers to the structure using... Figure 3 The structure shown in (a) uses a connecting member 206 to connect the pressure damper 204 and the inkjet head 102. Regarding existing structures, for example, it is also possible to consider a structure where the thickness of each location of the flow path 302 at the connecting member 206 is the same as the thickness of the output port 418 of the pressure damper 204. Alternatively, a direct connection structure refers to a structure that connects the pressure damper 204 and the inkjet head 102 without using the connecting member 206. More specifically, in a direct connection structure, a flexible tube with the same thickness as the output port 418 of the pressure damper 204 is used to connect the output port 418 of the pressure damper 204 to the inkjet head 102. Furthermore, in this experiment, the movement speed of the inkjet head 102 during the main scanning operation was set to a predetermined speed at which ink can be supplied from the pressure damper 204 relative to all nozzle rows at the inkjet head 102 when depicting the non-end regions 502 in the full-page printing area 500.

[0066] In addition, the items shown in the figure indicate whether unexpected ink splatter occurred when repeating a barcode-like image with a vertical line width of approximately 2 mm and a blank space of approximately 2 mm. The item indicating whether unexpected stripes occurred when performing full-page printing using a single inkjet head 102 at a specified printing resolution. As shown in the figure, when printing with the structure in this example, no problematic splatter or stripes occurred, and printing was performed appropriately. In contrast, when printing with the existing structure, small unexpected splatter occurred when printing barcode-like images, resulting in reduced print quality. When performing full-page printing, unexpected stripes occurred near the ends of the full-page printing area 500, resulting in reduced print quality. These stripes are stripes extending in the sub-scanning direction and arranged at certain intervals in the main scanning direction. Furthermore, in this experiment, barcode-like image printing and full-page printing were also performed using a direct connection structure without the connecting member 206. Furthermore, similar to the case using the existing structure, when printing barcode-like images, unexpected small splatters occur, reducing print quality. Also, when performing full-page printing, unexpected stripes appear near the ends of the full-page printing area 500, further reducing print quality.

[0067] Here, the inventors of this application performed printing using the aforementioned structures by varying the movement speed of the inkjet head 102 during the main scanning operation in multiple stages. Furthermore, it was confirmed that the aforementioned splattering and streaking problems did not occur when the movement speed of the inkjet head 102 was reduced. In addition, through various experiments, including those described above, the splattering and streaking problems occurring in existing structures and direct-connection structures were confirmed to be caused by the fact that the change in the amount of ink exiting from the output port 418 of the pressure damper 204 could not keep up with the change in the number of nozzle rows.

[0068] In contrast, when using the connecting member 206 of this example structure, by at least partially thickening the flow path 302 of the connecting member 206, ink can be adequately accumulated relative to the flow rate of ink exiting from the output port 418 of the pressure damper 204, for example, at a position closer to the pressure damper 204 and inkjet head 102. Furthermore, this allows for rapid and appropriate supply of the required amount of ink to the inkjet head 102, for example, when the amount of ink required by the inkjet head 102 changes, or when the change in the amount of ink exiting from the output port 418 of the pressure damper 204 is delayed. Therefore, when using the connecting member 206 of this example structure, even when the change in the amount of ink exiting from the output port 418 of the pressure damper 204 cannot keep up with the change in the number of nozzle rows, ink can be appropriately supplied to each nozzle of each nozzle row at the inkjet head 102. Furthermore, in this case, the movement speed of the inkjet head 102 during the main scanning operation can be considered to be a structure that causes problems in existing structures and direct connection structures, but can be appropriately used for printing in the structure of this example. Therefore, according to this example, for example, problems with print quality due to the influence of the pressure damper 204 can be appropriately prevented, and the movement speed of the inkjet head 102 during the main scanning operation can be appropriately increased. In addition, this allows for, for example, high-speed and high-quality printing.

[0069] Furthermore, in this case, considering the change in the amount of ink exiting from the output port 418 of the pressure damper 204, the movement speed of the inkjet head 102 during the main scanning operation can be considered, for example, as a situation where the change in the amount of ink exiting from the output port 418 of the pressure damper 204 cannot keep up with the change in the number of nozzle rows. In this case, the situation where the change in the amount of ink exiting from the output port 418 of the pressure damper 204 cannot keep up with the change in the number of nozzle rows can be considered, for example, as a situation where, during full-page printing, the change in the amount of ink exiting from the output port 418 of the pressure damper 204 cannot keep up with the change in the number of nozzle rows in at least one end region 504 on the main scanning direction. Additionally, in this case, the flow path 302 of the connecting member 206, since it is at least partially thickened, can also be considered to function as a buffer for ink flow. More specifically, in this case, by making at least a partial flow path cross-sectional area of ​​the flow path 302 at the connecting member 206 of the structure in this example larger than the flow path cross-sectional area of ​​the output port 418 of the pressure damper 204, the flow path 302 can be considered, for example, as a buffer for adjusting the ink flow rate between the output port 418 of the pressure damper 204 and the inkjet head 102. Furthermore, in this case, the flow path 302 at the connecting member 206 of the structure in this example can be considered, for example, to supply the amount of ink required for the number of nozzle rows to the nozzle rows of the inkjet head 102 when the change in the amount of ink exiting from the output port 418 of the pressure damper 204 cannot keep up with the change in the number of nozzle rows.

[0070] Furthermore, regarding the connecting member 206 in this example, a structure that uses a flow path 302 having a flow path cross-sectional area at least partially larger than the flow path cross-sectional area of ​​the output port 418 of the pressure damper 204 to supply ink to the inkjet head 102 from the pressure damper 204 can be considered as an example of a first ink supply structure. Moreover, in this case, if a structure using a flow path whose flow path cross-sectional area is less than the flow path cross-sectional area of ​​the output port 418 of the pressure damper 204 in all positions as the flow path to supply ink to the inkjet head 102 from the pressure damper 204 is considered as a second ink supply structure, then the characteristics of the movement speed of the inkjet head 102 during the main scanning operation and the operation of supplying ink to the inkjet head 102 via the connecting member 206 can also be considered from the differences between the first ink supply structure and the second ink supply structure. Furthermore, more specifically, in this case, for example, if we consider the end region 504 of the multiple end regions 504 in the full-page printing area 500 where the number of nozzle rows gradually increases, then the movement speed of the inkjet head 102 during the main scanning operation can be considered, for example, as a speed at which the ink supplied to the nozzle rows that should be ejected is insufficient at at least a portion of the time when ink is supplied to the inkjet head 102 using the second ink supply structure. In addition, in this case, in the connecting member 206 of the structure in this example, ink is supplied to the inkjet head 102 using the first ink supply structure, so that in the end region 504 where the number of nozzle rows gradually increases, ink can be supplied to the inkjet head 102 in a manner that does not result in insufficient ink supply to the nozzle rows that should be ejected.

[0071] Furthermore, as described above, the flow path 302 of the connecting member 206 in this example can be considered as a buffer for adjusting the ink flow rate. Moreover, regarding the case where the flow path 302 functions as a buffer, for example... Figure 6 As shown, we can also consider the flow rate of the ink flowing in the flow path. Figure 6 For flow path 302 (refer to) Figure 2 The diagram simplifies the flow rate of ink flowing in the ink.

[0072] Figure 6 (a) is a diagram illustrating the flow rate of ink flowing in a flow path different from the flow path 302 in this example, showing an example of the flow rate of ink flowing in a flow path where the cross-sectional area of ​​the flow path is a constant overall. Figure 6 (b) is a simplified diagram illustrating the flow rate of ink flowing in flow path 302 in this example, focusing on the cross-sectional area of ​​the flow path 302 at various locations, and showing the simplified structure corresponding to flow path 302. Additionally, in Figure 6 In (b), the portion of flow path 302 that is thicker than the first flow path 314 (see reference) Figure 2The first flow path section 312 on the upstream side (refer to) Figure 2 The cross-sectional area of ​​the flow path corresponding to the second flow path 314 is set as cross-sectional area a, and the cross-sectional area of ​​the flow path corresponding to the second flow path 314 is set as cross-sectional area b, which is greater than cross-sectional area a.

[0073] When liquids such as ink flow in a flow path with a defined cross-sectional area, the average velocity can generally be considered as the velocity obtained by dividing the volumetric flow rate by the cross-sectional area of ​​the flow path. Furthermore, the volumetric flow rate can also be considered as the product of the velocity and the cross-sectional area of ​​the flow path. Moreover, in this case, when liquids with the same volumetric flow rate flow with different cross-sectional areas of the flow path, the average velocity can be considered as inversely proportional to the cross-sectional area of ​​the flow path. More specifically, for example, for the same volumetric flow rate, if the cross-sectional area of ​​the flow path for the liquid is doubled, the average velocity becomes half.

[0074] In addition, for example, Figure 6 As shown in (a), with a constant flow path cross-sectional area, it can be assumed that the ink flow rate is the same at all locations along the flow path. Figure 6 In (a), the ink flow rate at each location in the flow path is illustrated as a predetermined flow rate V1. Furthermore, the flow rate V3 shown in the figure is the flow rate of ink flowing from the outlet of the flow path on the inkjet head 102 side towards the nozzle of the inkjet head 102. Regarding the flow rate V3, it can be considered, for example, the ink supply speed corresponding to the required amount of ink determined based on the amount of ink consumed in the inkjet head 102. In this case, the aforementioned flow rate V1 can be considered to be determined based on the flow rate V3.

[0075] In contrast, for example, Figure 6 As shown in (b), when the cross-sectional area of ​​the flow path varies depending on the location of the flow path, the ink velocity at each location of the flow path varies with the cross-sectional area of ​​the flow path. More specifically, as in flow path 302 in this example, for a flow path where ink flows from the inlet to the outlet without branching or merging along the way, the volumetric flow rate is the same at each location of the flow path. Furthermore, as a result, the ink velocity at each location is inversely proportional to the cross-sectional area of ​​the flow path. Moreover, in this case, the ink velocity V2 at the cross-sectional area b, which has a larger cross-sectional area, is slower than the ink velocity V1 at the portion of the flow path with a cross-sectional area of ​​cross-sectional area a.

[0076] In addition, regarding these structures, such as Figure 6As shown in (a), when using a flow path with a constant flow path cross-sectional area, for example, when the flow rate V3 corresponding to the ink supply rate changes, the ink flow rate V1 within the flow path typically changes proportionally to the change in flow rate V3. However, for example, when the flow rate V3 temporarily becomes particularly large, the flow rate V1 may temporarily exceed its range of variation. In contrast, for example, in Figure 6 In the case of the structure shown in (b), by making the ink flow rate V2 slower than the flow rate V1 at the portion with a larger flow path cross-sectional area b, the flow rate V2 can be appropriately varied, for example, even if the flow rate V3 temporarily becomes particularly high. Furthermore, this allows the portion with a larger flow path cross-sectional area b to function appropriately as a buffer, for example. Additionally, in this case, the portion with a larger flow path cross-sectional area b can also be considered for accumulating ink, for example, to supply ink to the inkjet head 102 in a timely manner.

[0077] Furthermore, regarding the specific structure used to obtain the effects described above, the flow path 302 of the connecting member 206 is not limited to the structure described above, and various modifications can be made. Figure 7 This is a diagram illustrating a modified example of the flow path 302 at the connecting member 206. Figure 7 of (a), Figure 7 (b) represents a variation of flow path 302. Except as described below, in Figure 7 The text is marked with the same meaning. Figures 1-5 The same reference numerals can have the same structure as Figures 1-5 The structures in the flow path 302 have the same or identical features. Furthermore, variations of the flow path 302 can be considered, for example, as follows: Figure 2 The variation of the flow path 302 used at the connecting member 206 shown in (b) of this example.

[0078] As explained above, regarding the flow path 302 at the connecting member 206, it is possible to consider, for example, making it at least partially thickened so that at least a portion of the flow path 302 functions as an ink accumulation section. In this regard, the above description mainly focused on the structure of thickening the second flow path portion 314 in the flow path 302. However, considering the possibility of making at least a portion of the flow path 302 function as an accumulation section, for example... Figure 7 As shown in (a), the case where the entire flow path 302 is thickened is also considered. More specifically, in this case, the cross-sectional area of ​​the flow path at each location is larger than the output port 418 of the pressure damper 204 (see reference). Figure 4The flow path cross-sectional area of ​​the inkjet head 102 is such that, for example, ink can be sufficiently accumulated relative to the flow rate of ink exiting from the output port 418 of the pressure damper 204 at a position closer to the pressure damper 204. Furthermore, this allows for sufficient ink accumulation at the inkjet head 102 (see reference 102). Figure 1 When the required amount of ink changes, the inkjet head 102 can be supplied with the required amount of ink quickly and appropriately.

[0079] Here, when using a connecting member 206 having such a flow path 302, it is also considered that the pressure damper 204 and the inkjet head 102 should have the same or identical structure as those described above. Therefore, regarding the thickness of the end of the flow path 302, it is considered, for example, to be the same as that of the output port 418 of the pressure damper 204 and the inlet 152 of the inkjet head 102 (see...). Figure 2 Matching thickness.

[0080] Furthermore, as in this modified example, when the entire flow path 302 at the connecting member 206 is thickened, for example, considering a significant increase in the size of the connecting member 206, it becomes difficult to place the connecting member 206 near the inkjet head 102, for example, considering that the area required to provide the connecting member 206 becomes larger. In contrast, as explained above, even when only a portion of the flow path 302 is thickened, the flow path 302 can still function appropriately as an ink accumulation section. Therefore, considering the need to suppress the increase in the size of the connecting member 206, it is preferable to only partially thicken the flow path 302 at the connecting member 206.

[0081] Furthermore, when using a structure that only locally thickens the flow path 302 at the connecting member 206, the following situation should also be considered: if a thinner portion exists near the inkjet head 102 than the thickened portion, the flow resistance of the thinner portion downstream increases compared to the thicker portion upstream, making it difficult for ink to flow towards the inkjet head 102, thus reducing the effectiveness of providing a thicker portion in the flow path 302. Therefore, when using a structure that only locally thickens the flow path 302 at the connecting member 206, it is preferable to thicken the portion connected to the inkjet head 102. In this case, for example... Figure 7 As shown in (b), consider locally thickening the downstream portion of the second flow path section 314, which is a straight section connected to the inkjet head 102. More specifically, in Figure 7In the modified example shown in (b), the cross-sectional area of ​​the first flow path portion 312 at the flow path 302 of the connecting member 206 and the cross-sectional area of ​​the upstream portion of the second flow path portion 314 are both values ​​S1 that match the cross-sectional area of ​​the flow path at the output port 418 of the pressure damper 204. Furthermore, the cross-sectional area of ​​the downstream portion of the second flow path portion 314 is a value S2 that is greater than S1. With this configuration, the increase in the size of the connecting member 206 can be more appropriately suppressed, and the flow path 302 of the connecting member 206 can appropriately have an ink accumulation function. Additionally, for example, an example of such a structure could be considered where the ink accumulation portion is located in the flow path 302 immediately before the inkjet head 102.

[0082] Next, supplementary explanations related to the structures already described above will be provided. Additionally, for ease of explanation, the following will also... Figure 7 The modified examples shown are included in this example. As explained above, in this example, by at least partially thickening the flow path 302 of the connecting member 206, at least a portion of the flow path 302 functions as an ink storage section. Regarding this, if sufficient ink is considered to accumulate between the pressure damper 204 and the inkjet head 102, it is also considered that an ink storage section such as a secondary ink tank can be used independently of the connecting member 206. However, in this case, in the carriage 110 (see...) Figure 1 In some cases, additional auxiliary containers would need to be added near the inkjet head 102. Furthermore, this results in problems such as difficulty in ensuring sufficient space for the components at the carriage 110 and increased costs. In contrast, in this example, ink can be adequately stored between the pressure damper 204 and the inkjet head 102 without adding new components.

[0083] Furthermore, regarding the situation where there is ample ink accumulation between the pressure damper 204 and the inkjet head 102, it might seem at first glance that simply increasing the ink supply capacity of the pressure damper 204 would suffice. However, as can be understood from the above explanation, issues such as ink splattering when printing barcode-like images and streaks in the end areas during full-page printing are not related to the supply capacity of the pressure damper 204, but rather to the rate of change in the amount of ink exiting from the output port 418 of the pressure damper 204. Also, regarding this point, as mentioned above, the pressure damper 204 uses a valve 410 (see...). Figure 4 Mechanical dampers, such as those used in inkjet printers, are employed. Furthermore, in this case, a certain amount of time is typically required to adjust the amount of ink output from the output port 418 of the pressure damper 204 to match the variation in the amount of ink required by the inkjet head 102. Therefore, even if the ink supply capacity of the pressure damper 204 is increased, it is difficult to adequately prevent the aforementioned problems of splattering and streaking.

[0084] In contrast, in this example, as described above, by at least partially thickening the flow path 302 at the connecting member 206, problems such as splattering and streaks can be appropriately prevented. Furthermore, in this case, it is considered that a sufficient amount of ink is accumulated in the thicker portion of the flow path 302, which functions as an ink accumulation section, thereby compensating for the delay in the amount of ink exiting from the output port 418 of the pressure damper 204. With this configuration, for example, even when the movement speed of the inkjet head 102 during the main scanning operation is increased to a high speed, the generation of unexpected splattering and streaks can be appropriately prevented. More specifically, regarding the amount of ink accumulated in the flow path 302 at the connecting member 206 in this example, it is considered, for example, to be more than twice the amount of ink accumulated if the flow path 302 were not thickened. In this case, the amount of ink accumulated in the flow path 302 can be considered, for example, as the volume of the flow path 302. Furthermore, regarding thickening at least partially of the flow path 302, it is considered, for example, to increase the volume of at least partially of the flow path 302. Furthermore, regarding the amount of ink accumulated when the flow path 302 is not thickened, for example, it is possible to consider the amount of ink accumulated in the flow path 302 when the cross-sectional area of ​​the flow path at each location is equal to the cross-sectional area of ​​the flow path at the output port 418 of the pressure damper 204. Additionally, regarding the amount of ink accumulated in the flow path 302 at the connecting member 206 in this example, it is more preferable to set it to at least three times the amount of ink accumulated when the flow path 302 is not thickened. Furthermore, when considering increasing the amount of ink accumulated in the flow path 302 at the connecting member 206, it is also considered that a longer flow path 302 can be used without at least partially thickening the flow path 302. However, in this case, it is considered that, for example, the connecting member 206 would become larger due to the formation of a longer flow path 302. Furthermore, if a longer flow path 302 is to be formed without increasing the size of the connecting member 206, it is considered that the number of bends in the flow path 302 would increase, making it difficult for ink to flow. Therefore, as described above, the flow path 302 preferably uses a structure that at least locally thickens.

[0085] Furthermore, as described above, in this example, the flow path 302 of the connecting member 206 has a flow path cross-sectional area that is at least partially larger than the flow path cross-sectional area of ​​the output port 418 of the pressure damper 204. However, for example, in a variation of the pressure damper 204, it is also possible to consider making the flow path cross-sectional area of ​​the output port 418 larger than the flow path cross-sectional area that matches the supply capacity of the pressure damper 204. Moreover, in this case, it is also considered that the flow path cross-sectional area of ​​the thicker portion in the flow path 302 is equal to or smaller than the flow path cross-sectional area of ​​the output port 418. Therefore, in such a case, the characteristics of the thicker portion in the flow path 302 can be considered as a flow path cross-sectional area that is not larger than the flow path cross-sectional area of ​​the output port 418, but larger than the flow path cross-sectional area that matches the supply capacity of the pressure damper 204. In addition, in this case, the thicker portion in the flow path 302 can be considered, for example, as the thickness of the ink accumulation section with the function of a buffer described above.

[0086] Furthermore, as explained above, in this example, the inkjet head 102 has six nozzle rows. Regarding this, it is believed that the aforementioned splatter and streaking problems are particularly prone to occur when the number of nozzle rows in an inkjet head 102 is large. More specifically, when the number of nozzle rows in an inkjet head 102 is large, the movement speed of the inkjet head 102 during the main scanning operation can generally be faster. Moreover, in this case, the amount of ink required by the inkjet head 102 changes more rapidly, and the change in the amount of ink exiting from the output port 418 of the pressure damper 204 can easily become untimely. Furthermore, as a result, for example, when using the conventional connecting member 206, splatter and streaking problems are more likely to occur. Additionally, when the number of nozzle rows in an inkjet head 102 is large, the number of ejected nozzle rows varies, and thus the amount of ink required by the inkjet head 102 also varies. Furthermore, in this case, since the number of nozzle rows is large, the possibility that the change in the amount of ink required due to a change of one nozzle row is small is also considered. Furthermore, in this case, the pressure damper 204 needs to ensure that the amount of ink exiting from the output port 418 changes in such a way whenever the number of nozzle rows changes: the difference in ink amount at each stage is small, and the ink amount changes in multiple stages corresponding to the number of nozzle rows. Moreover, in such a case, for example, it is difficult to consider that the operation of the valve 410 in the pressure damper 204 may not keep up with the required change in ink amount. Therefore, when the number of nozzle rows in an inkjet head 102 is large, if the movement speed of the inkjet head 102 during the main scanning operation becomes high, it is easy for the change in the amount of ink exiting from the output port 418 of the pressure damper 204 to fail to keep up with the change in the number of nozzle rows. Furthermore, as described above, this results in printing quality problems.

[0087] Furthermore, regarding this point, as explained above, for example, if the movement speed of the inkjet head 102 during the main scan operation is slowed down and the number of print passes is increased, the main scan operation can be performed in a way that allows the amount of ink exiting from the output port 418 of the pressure damper 204 to change in a timely manner. However, in this case, the printing speed is significantly reduced. In contrast, in this example, when the number of nozzle rows in an inkjet head 102 is large, even if the change in the amount of ink exiting from the output port 418 of the pressure damper 204 cannot keep up with the change in the number of nozzle rows, the ink supply to each nozzle row of the inkjet head 102 can be appropriately performed. Furthermore, this allows for, for example, higher-speed, higher-quality printing. In addition, when the number of nozzle rows in an inkjet head 102 is large, for example, if the maximum amount of ink consumed by the inkjet head 102 increases, and specific conditions occur during the main scan operation, there may be a situation where the amount of ink required by the inkjet head 102 changes drastically in stages. Furthermore, in this case, for example, consider the significant increase in the amount of ink required relative to the inkjet head 102, which may prevent the ink from being supplied from the pressure damper 204 in time. Additionally, in this case, if the conventional connecting member 206 is used, for example, the ink supply system 108 (see reference 108) could be used instead. Figure 2 If the ink supply rate to the inkjet head 102 cannot keep up with the ink consumption rate, the ink chambers and other ink stored in the inkjet head 102 will become empty, affecting print quality. In contrast, in this example, by using the connecting member 206 with the aforementioned structure, high-quality printing can be achieved more appropriately even in such cases. Furthermore, regarding the problems arising from an increased number of nozzle rows, these are considered to be more significant, for example, when the number of nozzle rows supplied with ink by the shared pressure damper 204 of the inkjet head 102 is four or more. Therefore, the connecting member 206 in this example is particularly preferred, for example, when the inkjet head 102 has four or more nozzle rows.

[0088] Additionally, regarding the printing device 100 (see reference) Figure 1 Self-inking container 106 (reference) Figure 1The path for supplying ink to the inkjet head 102 has been described above primarily focusing on the path for supplying ink of a single color. Regarding this, as explained above, in this example, the ink supply system 108 has a flow path 202, a pressure damper 204, and a connecting member 206 as a structure for supplying ink from the ink container 106 to one inkjet head 102. In this case, the ink supply system 108, for example, has a flow path 202, a pressure damper 204, and a connecting member 206 to supply ink from different ink containers 106 to each inkjet head 102. Furthermore, in this case, the ink supply system 108, for example, has multiple flow paths 202 corresponding to each inkjet head of the plurality of inkjet heads 102. Additionally, each inkjet head 102 may have a pressure damper 204 and a connecting member 206.

[0089] Alternatively, as the pressure damper 204 and the connecting member 206, a component obtained by combining structures corresponding to multiple inkjet heads 102 can also be used, for example. In this case, one pressure damper 204 may have multiple sets of... Figure 4 The structure is shown. Furthermore, in this case, regarding the pressure damper 204, it is possible to consider having flow paths within mutually independent adjustment mechanisms corresponding to the plurality of inkjet heads 102. In this case, the pressure damper 204 receives ink supply from the plurality of ink containers 106 via multiple independent flow paths 202 at multiple input ports 416. Additionally, ink is supplied to the plurality of inkjet heads 102 via connecting members 206 from multiple output ports 418, each corresponding to a specific inkjet head 102. More specifically, as the pressure damper 204, for example, it is possible to adjust the ink pressure using flow paths within the adjustment mechanisms of two systems corresponding to two inkjet heads 102.

[0090] Alternatively, as the connecting member 206, a member holding multiple pressure dampers 204 may be used, for example. In this case, the connecting member 206 supplies ink from the multiple pressure dampers 204 to multiple inkjet heads 102. Furthermore, in this case, the connecting member 206 has multiple independent flow paths 302, from which ink is supplied to each inkjet head 102. In this case, by using the flow paths 302 of the structure described above, high-speed and high-quality printing can be appropriately performed, for example. More specifically, as the connecting member 206, a member holding two pressure dampers 204 may be considered, for example. In this case, the connecting member 206 may also hold two pressure dampers 204, each having a flow path within an adjustment mechanism with two separate systems. With this configuration, ink can be supplied from one connecting member 206 to four inkjet heads 102, for example. Furthermore, this can appropriately reduce the ink consumption in the carriage 110 (see reference). Figure 1The number of components disposed around the inkjet head 102.

[0091] Furthermore, in the above description, the structure of the printing apparatus 100 was mainly described in the case of ink being ejected onto a medium. In this case, the printing apparatus 100 can be considered, for example, as an inkjet printer that draws a two-dimensional image on a medium. In contrast, in a variation of the printing apparatus 100, a 3D printer (3D printing apparatus) for creating three-dimensional objects can also be considered as the printing apparatus 100. In this case, the modeling platform supporting the object being modeled and the object being modeled can be considered as the object to be ejected from the ink. In this case, by supplying ink to the inkjet head 102 with the same structure as described above, the object can be modeled appropriately with high quality. In addition, the printing apparatus 100 can also be considered, for example, as an example of a liquid ejection device. In this case, the ink can be considered, for example, as an example of liquid ejected by a liquid ejection device.

[0092] Industrial availability

[0093] This invention can be preferably applied, for example, to a printing device.

Claims

1. A printing apparatus that performs printing by inkjet printing, characterized in that, The printing device has the following features: Inkjet head, which ejects ink in an inkjet manner; and An ink supply system that supplies ink to the inkjet head from an ink container that stores ink outside the inkjet head. The ink supply system has the following features: A pressure adjustment mechanism for adjusting the pressure of the ink supplied to the inkjet head; The container-side flow path is the path for ink to flow from the ink container to the pressure adjustment mechanism; and A connecting member, which connects the pressure adjustment mechanism and the inkjet head, forms an inkjet head-side flow path that serves as a flow path for ink to flow from the pressure adjustment mechanism to the inkjet head. The pressure adjustment mechanism adjusts the ink pressure to a specified range lower than atmospheric pressure, supplying it to the inkjet head side flow path via the pressure adjustment mechanism outlet connected to the inkjet head side flow path. The inkjet head-side flow path at the connecting member includes: a first flow path portion, which is a flow path for supplying ink flow in a portion of the inkjet head-side flow path; and a second flow path portion, which is a flow path for supplying ink flow at a position closer to the inkjet head than the first flow path portion. The cross-sectional area of ​​at least a portion of the second flow path is greater than the cross-sectional area of ​​the outlet of the pressure adjustment mechanism, and is also greater than the cross-sectional area of ​​the first flow path.

2. A printing apparatus that performs printing by inkjet printing, characterized in that, The printing device has the following features: Inkjet head, which ejects ink in an inkjet manner; and An ink supply system that supplies ink to the inkjet head from an ink container that stores ink outside the inkjet head. The ink supply system has the following features: A pressure adjustment mechanism for adjusting the pressure of the ink supplied to the inkjet head; The container-side flow path is the path for ink to flow from the ink container to the pressure adjustment mechanism; and A connecting member, which connects the pressure adjustment mechanism and the inkjet head, forms an inkjet head-side flow path that serves as a flow path for ink to flow from the pressure adjustment mechanism to the inkjet head. The pressure adjustment mechanism adjusts the ink pressure to a specified range lower than atmospheric pressure, supplying it to the inkjet head side flow path via the pressure adjustment mechanism outlet connected to the inkjet head side flow path. At least a portion of the flow path cross-sectional area at the connecting member on the inkjet head side is larger than the flow path cross-sectional area at the outlet of the pressure adjustment mechanism. The connecting member holds the pressure adjustment mechanism and connects the pressure adjustment mechanism and the inkjet head. The inkjet head side flow path is a flow path having at least one bend that changes the direction of ink flow. The inkjet head side flow path has: The first flow path is a flow path that supplies ink to flow upstream of the curved portion located at the outlet position closest to the inkjet head in the flow path on the inkjet head side. as well as The second flow path is a flow path for supplying ink closer to the inkjet head than the first flow path. The ink flows in a straight line in a certain direction to the outlet on the inkjet head side of the flow path. The cross-sectional area of ​​at least a portion of the second flow path is greater than the cross-sectional area of ​​the outlet of the pressure adjustment mechanism and is also greater than the cross-sectional area of ​​the first flow path.

3. The printing apparatus according to claim 1 or 2, characterized in that, The printing device also includes a main scan drive unit, which causes the inkjet head to perform a main scan operation while ejecting ink relative to the ink ejection target in a preset main scan direction. The inkjet head has four or more rows of nozzles arranged in a manner that makes the positions of the nozzles different in the direction of the nozzle rows orthogonal to the main scanning direction. Each of the nozzle arrays at the inkjet head is a nozzle array that ejects ink of the same color supplied from the pressure adjustment mechanism via the inkjet head side flow path, and is arranged in the main scanning direction in such a way that their positions are different in the main scanning direction.

4. A printing apparatus that performs printing by inkjet printing, characterized in that, The printing device has the following features: Inkjet head, which ejects ink in an inkjet manner; An ink supply system that supplies ink to the inkjet head from an ink container on the outside of the inkjet head; and The main scan drive unit causes the inkjet head to perform a main scan operation while ejecting ink, moving relative to the ink ejection target in a predetermined main scan direction. The ink supply system has the following features: A pressure adjustment mechanism for adjusting the pressure of the ink supplied to the inkjet head; The container-side flow path is the path for ink to flow from the ink container to the pressure adjustment mechanism; and A connecting member, which connects the pressure adjustment mechanism and the inkjet head, forms an inkjet head-side flow path that serves as a flow path for ink to flow from the pressure adjustment mechanism to the inkjet head. The pressure adjustment mechanism adjusts the ink pressure to a specified range lower than atmospheric pressure, supplying it to the inkjet head side flow path via the pressure adjustment mechanism outlet connected to the inkjet head side flow path. At least a portion of the flow path cross-sectional area at the connecting member on the inkjet head side is larger than the flow path cross-sectional area at the outlet of the pressure adjustment mechanism. The inkjet head has four or more rows of nozzles arranged in a manner that makes the positions of the nozzles different in the direction of the nozzle rows orthogonal to the main scanning direction. Each of the nozzle arrays at the inkjet head is a nozzle array that ejects ink of the same color supplied from the pressure adjustment mechanism via the inkjet head side flow path, and is arranged in the main scanning direction in such a way that their positions in the main scanning direction are different from each other. The action of ejecting ink from a nozzle at all ejection positions set according to the printing resolution is defined as full-page printing. The region near the end of the area where full-page printing is performed in the main scanning direction, where the number of nozzle rows ejecting ink changes simultaneously with the relative movement of the inkjet head in the main scanning direction during the main scanning action, is defined as a nozzle row number variation region. The portion of the area where full-page printing is performed, excluding the nozzle row number variation region, is defined as a nozzle row number constant region. In this case... In the main scanning action, The main scanning drive unit can supply ink from the pressure adjustment mechanism relative to all the nozzle rows at the inkjet head in the region where the number of nozzle rows is constant. Furthermore, in the nozzle number variation region on at least one side of the main scanning direction, the main scanning drive unit causes the inkjet head to move relative to the main scanning direction such that the change in the amount of ink exiting from the pressure adjustment mechanism cannot keep up with the change in the number of nozzles ejecting ink.

5. The printing apparatus according to claim 4, characterized in that, At least a portion of the cross-sectional area of ​​the inkjet head-side flow path at the connecting member is larger than the cross-sectional area of ​​the flow path at the outlet of the pressure adjustment mechanism. Thus, the inkjet head-side flow path of the connecting member functions as a buffer to adjust the ink flow rate between the outlet of the pressure adjustment mechanism and the inkjet head. When the change in the amount of ink exiting the outlet of the pressure adjustment mechanism cannot keep up with the change in the number of nozzles ejecting ink, the required amount of ink for the nozzles ejecting ink is supplied to the nozzles.

6. The printing apparatus according to claim 4 or 5, characterized in that, The pressure adjustment mechanism has: An ink accumulation section accumulates ink in the middle of the flow path of the ink supplied from the ink container toward the inkjet head in the pressure adjustment mechanism, i.e., the flow path within the adjustment mechanism. The pressure regulating section adjusts the pressure of the ink accumulated in the ink storage section to a pressure lower than atmospheric pressure; and A valve, which is disposed within the adjustment mechanism between the ink accumulation section and the inkjet head, has its flow path arranged in that direction. The ink accumulation section is an accumulation section with an opening. The voltage regulating unit has: A flexible membrane that covers the opening of the ink accumulation section in a state where the side opposite to the ink accumulation section is exposed to the atmosphere; and The force-applying component applies force to the flexible film in a direction away from the ink accumulation area. By applying force to the flexible membrane using the force-applying component, the pressure of the ink accumulated in the ink storage area is adjusted to be lower than atmospheric pressure. The valve opens and closes based on the difference between the pressure of the ink on the inkjet head side in the flow path of the adjustment mechanism and the pressure of the ink in the ink storage section, thereby causing the ink, whose pressure has been adjusted to the specified range, to flow toward the inkjet head.

7. The printing apparatus according to any one of claims 4 to 6, characterized in that, A structure that uses a connecting member in the inkjet head-side flow path having at least a local flow path cross-sectional area larger than the flow path cross-sectional area of ​​the pressure adjustment mechanism outlet to supply ink from the pressure adjustment mechanism to the inkjet head is defined as a first ink supply structure. A structure that uses a flow path whose flow path cross-sectional area is less than the flow path cross-sectional area of ​​the pressure adjustment mechanism outlet at all locations as the flow path for supplying ink from the pressure adjustment mechanism to the inkjet head is defined as a second ink supply structure. In this case, In the region of nozzle number variation on the side where the number of nozzles simultaneously ejecting ink gradually increases, the main scan drive unit moves the inkjet head relative to the main scan direction at a speed where, even when ink is supplied to the inkjet head using the second ink supply structure, the ink supplied to the nozzles that are to eject ink is insufficient at least for a portion of the time. The connecting member supplies ink to the inkjet head using the first ink supply structure, thereby supplying ink to the inkjet head in a manner that does not result in insufficient ink supply to the nozzles that should be ejecting ink, in the area of ​​the number of nozzles that are simultaneously ejecting ink and the region of the number of nozzles that are changing in number.

8. A printing method, wherein the printing method uses inkjet printing, characterized in that, For inkjet printheads that eject ink using an inkjet method, The ink supply system supplies ink to the inkjet head from an ink container that stores ink outside the inkjet head. The ink supply system has the following features: A pressure adjustment mechanism for adjusting the pressure of the ink supplied to the inkjet head; The container-side flow path is the path for ink to flow from the ink container to the pressure adjustment mechanism; and A connecting member, which connects the pressure adjustment mechanism and the inkjet head, forms an inkjet head-side flow path that serves as a flow path for ink to flow from the pressure adjustment mechanism to the inkjet head. The pressure adjustment mechanism, which adjusts the ink pressure to a specified range lower than atmospheric pressure, supplies ink to the inkjet head side flow path via the outlet of the pressure adjustment mechanism, which is connected to the inkjet head side flow path. The inkjet head-side flow path at the connecting member includes: a first flow path portion, which is a flow path for supplying ink flow in a portion of the inkjet head-side flow path; and a second flow path portion, which is a flow path for supplying ink flow at a position closer to the inkjet head than the first flow path portion. The cross-sectional area of ​​at least a portion of the second flow path is greater than the cross-sectional area of ​​the outlet of the pressure adjustment mechanism, and is also greater than the cross-sectional area of ​​the first flow path.

9. A printing apparatus that performs printing by inkjet printing, characterized in that, The printing device has the following features: Inkjet head, which ejects ink in an inkjet manner; and An ink supply system that supplies ink to the inkjet head from an ink container that stores ink outside the inkjet head. The ink supply system has the following features: A pressure adjustment mechanism for adjusting the pressure of the ink supplied to the inkjet head; The container-side flow path is the path for ink to flow from the ink container to the pressure adjustment mechanism; and The inkjet head side flow path is the flow path for ink supplied from the pressure adjustment mechanism to the inkjet head. The pressure adjustment mechanism adjusts the ink pressure to a specified range lower than atmospheric pressure, supplying it to the inkjet head side flow path via the pressure adjustment mechanism outlet connected to the inkjet head side flow path. The inkjet head side flow path includes: a first flow path section, which is a flow path for supplying ink flow in a portion of the inkjet head side flow path; and a second flow path section, which is a flow path for supplying ink flow at a position closer to the inkjet head than the first flow path section. The cross-sectional area of ​​at least a portion of the second flow path is larger than the cross-sectional area of ​​the outlet of the pressure adjustment mechanism, and is also larger than the cross-sectional area of ​​the first flow path. The inkjet head side flow path accumulates ink at the portion before the inkjet head, thereby functioning as a buffer to adjust the ink flow rate between the pressure adjustment mechanism outlet and the inkjet head. When the change in the amount of ink from the pressure adjustment mechanism outlet cannot keep up with the change in the amount of ink required by the inkjet head, the inkjet head is supplied with the amount of ink required by the inkjet head.

10. A printing method, wherein the printing method uses inkjet printing, characterized in that, For inkjet printheads that eject ink using an inkjet method, The ink supply system supplies ink to the inkjet head from an ink container that stores ink outside the inkjet head. The ink supply system has the following features: A pressure adjustment mechanism for adjusting the pressure of the ink supplied to the inkjet head; The container-side flow path is the path for ink to flow from the ink container to the pressure adjustment mechanism; and The inkjet head side flow path is the flow path for ink supplied from the pressure adjustment mechanism to the inkjet head. The pressure adjustment mechanism, which adjusts the ink pressure to a specified range lower than atmospheric pressure, supplies ink to the inkjet head side flow path via the outlet of the pressure adjustment mechanism, which is connected to the inkjet head side flow path. The inkjet head side flow path includes: a first flow path section, which is a flow path for supplying ink flow in a portion of the inkjet head side flow path; and a second flow path section, which is a flow path for supplying ink flow at a position closer to the inkjet head than the first flow path section. The cross-sectional area of ​​at least a portion of the second flow path is larger than the cross-sectional area of ​​the outlet of the pressure adjustment mechanism, and is also larger than the cross-sectional area of ​​the first flow path. Regarding the inkjet head side flow path, ink accumulates in the portion before the inkjet head, thereby functioning as a buffer to adjust the ink flow rate between the pressure adjustment mechanism outlet and the inkjet head. When the change in the amount of ink exiting the pressure adjustment mechanism outlet cannot keep up with the change in the amount of ink required by the inkjet head, the inkjet head side flow path supplies the inkjet head with the amount of ink required by the inkjet head.

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