Liquid ejecting head, liquid ejecting unit, liquid ejecting apparatus, liquid ejecting method, and program product

Abstract

The present invention relates to a liquid ejecting head, a liquid ejecting unit, a liquid ejecting apparatus, a liquid ejecting method, and a program product, which can suppress deviation of a landing position or ejection bending of an ejected droplet, and can suppress white stripes / black stripes of a seam of the ejecting head. A liquid ejecting head that selectively ejects two or more types of droplets having different ejection droplet amounts from a nozzle and performs gradation expression of a concentration corresponding to an input gradation value includes an ejection control unit that performs control to eject a liquid droplet in the liquid ejecting head in accordance with the input gradation value. And a control unit that controls the nozzles such that only the largest one of the two or more types of droplets is ejected from the nozzles in a high gradation portion of the input gradation value, and that includes a portion such that the number of nozzles that do not eject among all the nozzles does not increase in a monotonically decreasing manner from a low gradation portion of the input gradation value to the high gradation portion of the input gradation value.

Description

Technical Field

[0001] The present invention relates to a liquid ejection head, a liquid ejection unit, a device for ejecting a liquid, a liquid ejection method, and a program product. Background Art

[0002] Patent Document 1 discloses a nozzle head control method and an image processing technique, in which in a liquid ejection head, gradation expression of density is performed by ejecting liquid droplets having different ejection droplet amounts (large droplets, medium droplets, small droplets, etc.).

[0003] More specifically, the technique disclosed in Patent Document 1 is to perform gradation expression of density, and in a low gradation portion, it is expressed by a small dot size formed by small droplets, in an intermediate gradation portion, the ratio of the small dot size is reduced and medium dots formed by medium droplets are mixed, and in a high gradation portion, the ratio of the medium dot size is reduced and large dots formed by large droplets are mixed.

[0004] However, according to the prior art, if the number of liquid droplets ejected simultaneously during gradation expression increases, there is a problem that the airflows generated by the ejected liquid droplets interfere with each other and the ejected liquid droplets are bent. In particular, as the distance from the nozzle of the liquid ejection head to a recording medium such as paper increases, this problem becomes more significant.

[0005] Specifically, in the case where accompanying droplets or the like are generated in the ejected liquid droplets, unevenness such as a wood grain pattern is generated when the accompanying droplets are carried away by the airflow and land. In addition, in the nozzles at the end of the liquid ejection head, a deviation occurs in the affected airflow, and the landing position tends to shift (bend easily). In particular, in the case of performing printing by arranging a plurality of liquid ejection heads, white stripes / black stripes are likely to occur at the joints of the liquid ejection heads.

[0006] In addition, in order to solve the above problems, although there is a method of increasing non-ejecting nozzles of the liquid ejection head, a method of increasing them more effectively is required.

[0007] The present invention has been made in view of the above problems, and an object thereof is to suppress deviation of the landing position or bending of the ejection of the ejected liquid droplets, and also to suppress white stripes / black stripes at the joints of the nozzle heads.

[0008] [Patent Document 1] Japanese Patent No. 5709394 Gazette Summary of the Invention

[0009] In order to solve the above problems and achieve the object, the present invention relates to a liquid ejection head that selectively ejects two or more types of droplets with different ejection droplet amounts from a nozzle to perform gradation expression of a density corresponding to an input gradation value, and is characterized by including: an ejection control unit that controls so that only the largest droplet among the two or more types of droplets is ejected from the nozzle in a high gradation portion of the input gradation value, and includes a portion in which the number of nozzles that do not eject among all the nozzles increases non-monotonically decreasingly from a low gradation portion to a high gradation portion of the input gradation value.

[0010] According to the present invention, it is possible to obtain effects such as being able to suppress deviation of the landing position or ejection bending of the ejected droplets, and being able to suppress white stripes / black stripes, etc. of the joint of the ejection head. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 Shown is a perspective stereogram of the inside of an image forming apparatus according to a first embodiment.

[0012] Figure 2 Shown is a schematic diagram of the configuration of an image forming apparatus.

[0013] Figure 3 Shown is a block diagram example of the hardware configuration of an image forming apparatus.

[0014] Figure 4 Shown is a block diagram example of the functional configuration of a control unit.

[0015] Figure 5 Is a graph showing the relationship between an existing input level and a landing ratio.

[0016] Figure 6 Shown is a graph of the relationship between an input level and a landing ratio.

[0017] Figure 7 Shown is a graph of the relationship between an input level and an output level.

[0018] Figure 8 Is an exemplary diagram of the transition of white pixels.

[0019] Figure 9 Shown is a graph of the relationship between an input level and a landing ratio according to a second embodiment.

[0020] Figure 10 Shown is a graph of the relationship between an input level and an output level.

[0021] Figure 11 Shown is a schematic diagram of an example of a manufacturing apparatus for an electrode according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, embodiments of a liquid ejection head, a liquid ejection unit, a device for ejecting a liquid, a liquid ejection method, and a storage medium will be described in detail with reference to the accompanying drawings.

[0023] Hereinafter, as an example of a device for ejecting a liquid to which the present invention is applicable, an image forming apparatus as one mode of the device for ejecting a liquid will be described, but the present invention is not limited thereto.

[0024] (First Embodiment)

[0025] Figure 1 Shown is a perspective three-dimensional view of the interior of an image forming apparatus 100 according to the first embodiment. Figure 2 Shown is a schematic diagram of the configuration of the image forming apparatus 100. As Figure 1 and Figure 2 shown, the image forming apparatus 100 according to the present embodiment is a wide-format serial inkjet recording apparatus.

[0026] In addition, in the present embodiment, an example in which the device for ejecting a liquid of the present invention is applied to wide-format serial inkjet is described, but any image forming apparatus such as a multi-functional peripheral device, a copying machine, a printer, a scanning device, a facsimile device, etc., having at least two functions among a copying function, a printer function, a scanning function, and a facsimile function can be applied thereto.

[0027] As Figure 1 and Figure 2 shown, the image forming apparatus 100 includes side plates 21A and 21B on the left and right of the apparatus main body 100a. The side plates 21A and 21B horizontally support a main guide bar 31 as a guiding member. In addition, the image forming apparatus 100 further includes a sub-metal plate guide 32. The main guide bar 31 and the sub-metal plate guide 32 hold the carriage 121 so as to be slidable.

[0028] The carriage 121 moves in the direction of arrow G (carriage main scanning direction) via a timing belt that is rotationally driven by a main scanning motor 117 (see Figure 3 ), so as to relatively move with respect to a medium 40 as a recording medium. The movement of the carriage 121 may also be referred to as scanning. In addition, an optical sensor 37 for detecting an end portion (paper end portion) of the medium 40 is mounted on the carriage 121.

[0029] The optical sensor 37 is an example of a reading unit that outputs a reading signal of an image previously formed by the image forming apparatus 100 on the medium 40. In the present embodiment, the image forming apparatus 100 detects an abnormality of the image based on the reading signal of the optical sensor 37. As the optical sensor 37, a device that detects based on the reflection density, a camera that photographs the image formed on the medium 40, or the like can be used. In addition, in the present embodiment, the abnormality of the image also includes a sign of an abnormality as a state in which an abnormality may occur.

[0030] The carriage 121 includes liquid ejection heads 122a, 122b, 122c that eject liquid droplets (liquids) of various colors such as yellow (Y), cyan (C), magenta (M), black (K), orange (O), green (G), and clear (Cl) according to the ink cartridges 10 installed thereon (when not distinguishing, these three liquid ejection heads 122a, 122b, 122c are collectively referred to as "liquid ejection head 122").

[0031] The medium 40 moves in a sub-scanning direction (direction of arrow H) substantially perpendicular to the main scanning direction by using a conveyance roller rotationally driven by a sub-scanning motor 118 (see Figure 3 ), and thus moves relative to the liquid ejection head 122. However, the main scanning direction and the sub-scanning direction do not necessarily have to be substantially orthogonal, as long as they intersect.

[0032] The liquid ejection head 122 arranges nozzle rows each composed of a plurality of nozzles (not shown) in the sub-scanning direction. The liquid ejection head 122 is installed such that the ink droplet ejection direction from the nozzles faces downward. The liquid ejection heads 122a, 122b, 122c are respectively arranged offset from each other in the sub-scanning direction. The carriage 121 is equipped with sub-tanks for supplying inks of various colors according to the liquid ejection head 122.

[0033] A "liquid ejection head" is a functional part that ejects an ejection liquid from a nozzle. The "liquid" to be ejected only needs to have a viscosity and surface tension that can be ejected from the liquid ejection head 122, and there is no particular limitation. Preferably, it is a liquid having a viscosity of 30 MPa·s or less at normal temperature and pressure or when heated or cooled. More specifically, it includes solutions, suspensions, emulsions, etc. of solvents such as water or organic solvents, colorants such as dyes and pigments, functional imparting materials such as polymerizable compounds, resins, and surfactants, bio-compatible materials such as DNA, amino acids, proteins, and calcium, and edible materials such as natural pigments. They can be used for, for example, inkjet inks, surface treatment liquids, constituent elements of electronic components and light-emitting elements, liquids for forming patterns of electronic circuit resist layers, three-dimensional modeling material liquids, and other uses.

[0034] As an energy source for ejecting liquid, there is an energy source that uses a piezoelectric actuator (a laminated piezoelectric element and a thin-film piezoelectric element) or the like.

[0035] In addition, the "liquid ejection head" is not limited to the pressure generating mechanism used. For example, in addition to the above piezoelectric actuator (a laminated piezoelectric element may also be used), a thermal actuator using a heat conversion element such as a heating resistor, an electrostatic actuator composed of a diaphragm and a counter electrode, etc. may also be used.

[0036] The image forming apparatus 100 includes an ink cartridge loading portion 1, to which ink cartridges 10y, 10c, 10m, 10k of various colors are detachably assembled (collectively referred to as "ink cartridge 10" when not distinguished).

[0037] The ink of the ink cartridge 10 is replenished and supplied to the sub-tank of the carriage 121 through the supply pump unit via the supply pipes 36 of each color. The supply pump unit and the supply pipes 36 constitute a supply mechanism. In addition, the ink cartridge 10 may also include a white ink cartridge.

[0038] The image forming apparatus 100 has a maintenance and recovery mechanism 81 in a non-printing area on one side in the main scanning direction of the carriage 121. The maintenance and recovery mechanism 81 maintains and / or recovers the state of the nozzles of the liquid ejection head 122.

[0039] The maintenance and recovery mechanism 81 includes cover members 82a, 82b, 82c for covering each nozzle surface of the liquid ejection head 122 (collectively referred to as "cover member 82" when not distinguished), a wiping unit 83 for wiping the nozzle surface, etc. In addition, a replaceable waste liquid tank for accommodating the waste liquid generated by the maintenance and recovery operation is provided on the lower side of the maintenance and recovery mechanism 81 of the liquid ejection head 122.

[0040] The "liquid ejection unit" refers to a component in which functional parts and mechanisms are integrated on the liquid ejection head 122, and is an aggregate of parts related to the ejection of liquid. For example, the "liquid ejection unit" includes a combination of at least one of a head tank (sub-tank of the carriage 121), a carriage, a supply mechanism, a maintenance and recovery mechanism, and a main scanning movement mechanism with the liquid ejection head 122.

[0041] Here, integration means that, for example, the liquid ejection head 122 and the functional parts and mechanisms are fixed to each other by fastening, bonding, clamping, etc., and one is held relative to the other so as to be movable. In addition, the liquid ejection head 122 and the functional parts and mechanisms may also be configured to be detachable from each other.

[0042] For example, as a liquid ejection unit, there is one formed by integrating a liquid ejection head 122 and an ink tank. Additionally, there is a device that integrates the liquid ejection head 122 and the ink tank by connecting them to each other through a hose or the like. Here, a unit containing a filter may also be added between the ink tank of these liquid ejection units and the liquid ejection head 122.

[0043] Additionally, as a liquid ejection unit, there is a device formed by integrating a liquid ejection head 122 and a carriage.

[0044] Additionally, as a liquid ejection unit, there is also one that movably holds the liquid ejection head 122 on the main guide shaft 31 of a guide member that forms a part of the main scanning movement mechanism, thereby integrating the liquid ejection head 122 and the scanning movement mechanism. Additionally, there is one formed by integrating the liquid ejection head 122, the carriage, and the main scanning movement mechanism.

[0045] Additionally, as a liquid ejection unit, there is also a configuration in which a cover member 82 that is a part of the maintenance and recovery mechanism 81 is fixed to the carriage on which the liquid ejection head 122 is mounted, thereby integrating the liquid ejection head 122, the carriage, and the maintenance and recovery mechanism 81.

[0046] Additionally, as a liquid ejection unit, there is one in which a supply hose 36 is connected to the liquid ejection head 122 in which an ink tank or a flow path component is installed, thereby integrating the liquid ejection head 122 and the supply mechanism. Through this hose, the liquid from the liquid storage source is supplied to the liquid ejection head 122.

[0047] The main scanning movement mechanism further includes the main guide shaft 31 alone as a guide member. Additionally, the supply mechanism also includes the supply hose 36 alone and the ink cartridge loading portion 1 alone.

[0048] Figure 3 Shown is a module diagram of the hardware configuration of the image forming apparatus 100. As Figure 3 shown, the image forming apparatus 100 includes a control unit 101, an operation panel 114, an environment sensor 115, an optical sensor 37, a head driver 116, a main scanning motor 117, a sub-scanning motor 118, a fan 119, a heater 120, a liquid ejection head 122, and a movement mechanism 140.

[0049] As Figure 3As shown, the control unit 101 includes a CPU (Central Processing Unit) 102, a ROM (Read Only Memory) 103, a RAM (Random Access Memory) 104, a non-volatile memory (NVRAM: Non-Volatile RAM) 105, an ASIC (Application Specific Integrated Circuit) 106, an I / F 107, a print control unit 108, a main scanning motor drive unit 109, a sub-scanning motor drive unit 110, a fan control unit 111, a heater control unit 112, and an I / O 113. Additionally, the control unit 101 may also include components other than those described above.

[0050] The CPU 102, ROM 103, RAM 104, non-volatile memory 105, ASIC 106, I / F 107, print control unit 108, main scanning motor drive unit 109, sub-scanning motor drive unit 110, fan control unit 111, heater control unit 112, and I / O 113 are connected to each other via a bus or the like, for example, so as to be able to communicate with each other.

[0051] The CPU 102 controls the overall operation of the image forming apparatus 100. Specifically, the CPU 102 realizes each function by executing programs stored in the ROM 103 and the like.

[0052] The ROM 103 stores programs executed by the CPU 102, other fixed data, etc. The RAM 104 temporarily stores image data and the like. The non-volatile memory 105 retains data even when the power supply of the image forming apparatus 100 is cut off. The ASIC 106 is a circuit for processing image processing such as performing various signal processing and rearrangement, and other input / output signals for controlling the entire apparatus.

[0053] The I / F 107 is an interface circuit for transmitting and receiving data and signals to and from the host side. Specifically, the I / F 107 receives print data (image data) and the like generated by a printer driver of a host such as an information processing apparatus, an image reading apparatus, and a photographing apparatus via a cable or a network. That is, the generation and output of print data to the control unit 101 may also be performed by the printer driver on the host side.

[0054] The print control unit 108 is a circuit that generates a drive waveform for driving the liquid ejection head 122, and at the same time outputs print data for selecting a drive pressure generating mechanism and various data accompanying it to the head driver 116. This pressure generating mechanism generates a pressure for causing the liquid ejection head 122 to eject liquid (ink).

[0055] The main scanning motor drive unit 109 is a circuit for driving the main scanning motor 117. The sub-scanning motor drive unit 110 is a circuit for driving the sub-scanning motor 118. The fan control unit 111 is a circuit for controlling the output of the fan 119 to perform air supply at a specified temperature and air volume.

[0056] The heater control unit 112 is a circuit for controlling the heater 120 to reach a set temperature. The I / O 113 is a circuit for obtaining information from the environment sensor 115 and extracting information required for controlling each part of the image forming apparatus 100. The I / O 113 also receives detection signals from various sensors (e.g., the optical sensor 37) other than the environment sensor 115.

[0057] The operation panel 114 is a device for inputting and displaying various information such as user-specified resolution. The operation panel 114 is communicably connected to the CPU 102 etc. via the bus of the control unit 101, for example.

[0058] The environment sensor 115 is a sensor for detecting environmental temperature, environmental humidity, etc., for example. The environment sensor 115 is connected to the I / O 113 of the control unit 101.

[0059] The nozzle driver 116 is a circuit for driving the liquid ejection head 122 by selectively applying drive pulses that make up the drive waveform provided from the print control unit 108 to the pressure generation unit of the liquid ejection head 122 based on the input image data (e.g., dot pattern data). The nozzle driver 116 is connected to the print control unit 108 of the control unit 101. In addition, the control of the ejection amount is performed, for example, by controlling the amplitude of the drive waveform input to the pressure generation unit of the liquid ejection head 122, but other means can also be used to control the ejection amount.

[0060] The main scan motor 117 is a device that rotates the drive timing belt by driving and moves the carriage 121 having the liquid ejection head 122 in the main scan direction (the direction of arrow G). The main scan motor 117 is connected to the main scan motor drive unit 109 of the control unit 101.

[0061] The sub-scan motor 118 is a device that drives the conveyance roller to convey the medium 40, which is the object of ejection of the liquid (ink liquid) of the liquid ejection head 122, in the sub-scan direction. The sub-scan motor 118 is connected to the sub-scan motor drive unit 110 of the control unit 101.

[0062] The moving mechanism 140 relatively moves the liquid ejection head 122 and the medium 40. The moving mechanism 140 includes a main guide rod 31, a sub-metal plate guide 32, a carriage 121, a conveyance roller, etc., and constitutes a main scan moving mechanism.

[0063] The moving mechanism 140 relatively moves the liquid ejection head 122 and the medium 40 along the main scanning direction by means of the main guide rod 31, the sub-metal sheet guide 32, the carriage 121, etc. In addition, the moving mechanism 140 relatively moves the liquid ejection head 122 and the medium 40 along the sub-scanning direction by means of the conveyance rollers for conveying the medium 40, etc. In the present embodiment, the relative movement of the moving mechanism 140 in the sub-scanning direction is an intermittent movement. The intermittent movement means a movement that alternately moves and stops.

[0064] The fan 119 is a device that promotes the convection of air inside the image forming apparatus 100 by driving, and is used to prevent the temperature of the upper part of the image forming apparatus 100 from rising excessively due to the retention of heated air. The fan 119 is connected to the fan control unit 111 of the control unit 101.

[0065] Figure 4 Shown is a module legend of the functional configuration of the control unit 101. In addition, the description of the constituent parts that are repeated is omitted. Figure 3 Repeat the description of the constituent parts.

[0066] As Figure 4 Shown, the control unit 101 includes a color plate division data generation unit 211 and an ejection control unit 212. The ejection control unit 210 controls the ejection of ink.

[0067] In the present embodiment, the control unit 101 includes a color plate division data generation unit 211 and an ejection control unit 212.

[0068] When inputting image data to be printed, the color plate division data generation unit 211 generates color plate division data of various colors of the ink installed in the image forming apparatus 100 from the input image data (an example of the input image). For example, when the image forming apparatus 100 uses CMYK ink for printing, the color plate division data generation unit 211 generates color plate division data of each color of CMYK from the input image data.

[0069] The ejection control unit 212 applies a dot pattern data generation mask to the color plate division data of each color generated by the color plate division data generation unit 211 to generate dot pattern data. Here, the dot pattern data generation mask is, for example, a dither mask with a set threshold for halftone processing. At this time, the ejection control unit 212 transforms the image data into dot pattern data including at least two or more types of dots.

[0070] In the present embodiment, the dot pattern data is 4 gray levels including dots of small droplets, dots of large droplets with a larger droplet volume than the dots of the small droplets, and dots of medium droplets with a larger droplet volume than the dots of the small droplets and a smaller droplet volume than the dots of the large droplets. In the present embodiment, an example is given where the ejection droplet volume of the small droplets is 6 pL, the ejection droplet volume of the medium droplets is 12 pL, and the ejection droplet volume of the large droplets is 18 pL.

[0071] The control unit 101 implements these functions (the color separation data generation unit 211 and the ejection control unit 212) by the CPU 102 executing a prescribed program. In addition, the control unit 101 may also implement a part or all of these functions by one or more processing circuits.

[0072] "Processing circuit" refers to a programmed processor that executes each function by software like a processor installed with an electronic circuit, an ASIC (application specific integrated circuit) designed to execute each function described above, a DSP (digital signal processor), an FPGA (field programmable gate array), an existing circuit module, and other devices.

[0073] The control unit 101 controls the liquid ejection head 122 and the moving mechanism 140 so that the liquid ejection head 122 and the medium 40 relatively move multiple times, while disposing the ink on the medium 40. The ink disposed on the medium 40 forms dots in the image by being fixed on the medium 40. More specifically, after one ink droplet ejected from the liquid ejection head 122 lands on the medium 40, it dries and is fixed on the medium 40, thereby forming one dot in the image. The image is formed as a collection of multiple dots.

[0074] Next, an example of the discrimination of dots of various dot types (hereinafter referred to as droplet types) performed by the ejection control unit 212 will be described.

[0075] Here, Figure 5 is a graph showing the relationship between the existing input level and the drop ratio. In Figure 5 the horizontal axis represents the input level (input gray value), and the vertical axis represents the drop ratio (drop rate). The input level (InputLevel) represents the level of concentration. When the input level is represented by gray levels, 0% represents white, and 100% represents black. The drop ratio (DropRatio) represents the usage rate of the ejection droplet or dot size at this time. A drop ratio of 0% means not used, and 100% means filling the entire surface with this dot.

[0076] In Figure 5 "Small" represents a small droplet or small dot size, "Middle" represents a medium droplet or medium dot size, "Large" represents a large droplet or large dot size, and "WhitePixel" represents that no droplet has fallen.

[0077] In Figure 5In the example shown, when the input level is 0%, small, medium, and large are all 0%, indicating that no droplets are ejected. Therefore, the white pixels are 100%. Additionally, when the input level is 16.7%, the usage rate of small is 50%, and the usage rates of medium and large are 0%, so the white pixels are 50%. Further, when the input level is 50%, the usage rates of small and medium are 50% respectively, and that of large is 0%, so the white pixels are 0%.

[0078] In Figure 5 In the gray-scale representation shown, small dot sizes are used up to 100%, and then replaced by medium droplets. After the medium droplets reach 100%, the medium droplets are replaced by large droplets this time, so smooth gray-scale representation can be achieved.

[0079] However, in Figure 5 the example shown, at the moment when the input level is 33%, the white pixels are 0%, resulting in a larger airflow caused by the ejected droplets themselves.

[0080] In addition, when the distance from the nozzle of the liquid ejection head 122 to the medium 40 is short (usually about 1 - 2 mm), since it lands on the medium 40 before being affected by the airflow of the ejected droplets themselves, the influence on the landing position deviation and ejection bending is slight. However, when the distance from the nozzle of the liquid ejection head 122 to the medium 40 becomes longer, being affected by the airflow of the ejected droplets themselves, landing position deviation, ejection bending, etc. will occur. In particular, droplets with relatively small sizes, such as small droplets and medium droplets, are more easily affected by the airflow of the ejected droplets themselves, and thus are more likely to have landing position deviation and ejection bending.

[0081] Therefore, in this embodiment, the ejection airflow is suppressed, interference between ejection airflows is prevented, and ejection bending of ejected droplets is suppressed. The following will be described in detail.

[0082] Here, Figure 6 is a graph showing the relationship between the input level and the landing ratio, Figure 7 and the figure shown is a graph of the relationship between the input level and the output level. In Figure 6 it, the horizontal axis represents the input level (input gray value), and the vertical axis represents the landing ratio (landing rate). In Figure 7 it, the horizontal axis represents the input level (InputLevel), and the vertical axis represents the output level (OutputLevel).

[0083] As Figure 6 shown, the types of droplets used for printing are controlled and replaced. For example, as Figure 6As shown, the ejection control unit 212 converts the input image into dot pattern data such that in the low gray-scale portion, the proportion of small droplets and medium droplets among all the droplets is larger than that in the high gray-scale portion, and the proportion of large droplets among all the droplets is smaller.

[0084] More specifically, as Figure 6 shown, in the present embodiment, the ejection control unit 212 suppresses the usage rate of small droplets and starts using medium droplets from 10% of the low input level. The ejection control unit 212 reduces the usage rate of small ink droplets from 10% of the input level at which medium droplets start to be used.

[0085] In the present embodiment, the ejection control unit 212 increases the landing ratio (ejection nozzle) of medium droplets to 15%.

[0086] Similarly, in the present embodiment, the ejection control unit 212 also suppresses the usage rate of medium droplets and reduces the usage rate of medium droplets starting from 13% of the input level at which large droplets start to be used. The ejection control unit 212 stops using medium droplets at 15% before the input level reaches 100%. Such control is because large droplets are less affected by air flow compared to medium droplets and small droplets, and in addition, large droplets spread compared to medium droplets and small droplets, so the appearance does not change.

[0087] In addition, as Figure 7 shown, when determining the usage rate, the ratio of the output level to the input level is preferably a substantially linear relationship. That is, the ejection control unit 212 performs control such that as the input level (input gray value) increases, the ratio of the output level (the ejection droplet amount of each droplet) does not decrease. The output level at this time can be either the adhesion amount of the liquid per unit area or the image density, etc. By making the output level linear with respect to the input level, the influence of the γ curve or the gray-scale jump in color matching, etc., used to determine the final tone, etc., can be minimized.

[0088] As described above, the ejection control unit 212 ejects only the largest droplet among two or more droplets from the nozzle in the high gray-scale portion of the input gray value, and includes a portion where the number of nozzles that do not eject among all the nozzles increases non-monotonically from the low gray-scale portion to the high gray-scale portion of the input gray value.

[0089] In other words, the ejection control unit 212 only patterns in dot sizes in the high gray-scale portion of the input gray value, and includes a portion where the ratio of pixels that do not have dots configured with respect to the input gray value increases from the low gray-scale portion to the high gray-scale portion.

[0090] Here, the reason for the temporary increase in white pixels when suppressing the usage rate of small droplets and starting to use medium droplets in the curve graph shown in Figure 6 is explained.

[0091] Here, Figure 8 an exemplary transition of white pixels is shown. Figure 8 The grid shown corresponds to white pixels (WhitePixel). As Figure 8 shown in (a) of, in the prior art, when increasing the landing ratio (spray nozzles) with small droplets, the empty grids (i.e., white pixels) decrease. At this time, in the case of a landing ratio of 100%, it is the state where spraying is performed from all nozzles. That is, in the case of a landing ratio of 100%, since spraying is performed from many nozzles, it becomes a state vulnerable to the influence of airflows.

[0092] On the other hand, as Figure 8 shown in (b) of, in the present embodiment, by replacing the portion depicted with small droplets with medium or large droplets, the number of nozzles for spraying is reduced without changing the depicted concentration. By reducing the number of nozzles for spraying in this way, the influence of the airflow of the sprayed droplets themselves can be reduced.

[0093] In addition, simultaneously, when the droplets are replaced with medium or large droplets, the blank grids = white pixels increase compared to 100% of small droplets. That is, in the Figure 6 shown graph, when suppressing the usage rate of small droplets and starting to use medium droplets from 10% of the low input level, the white pixels temporarily increase.

[0094] According to the present embodiment, for example, the usage rate of small droplets is suppressed, and medium droplets are started to be used from 10% of the low input level. From 10% of the input level at which medium droplets start to be used, the usage rate of small droplets is also reduced. Although the medium droplets increase to 15%, in order to ensure the same printing density, the nozzles used for medium droplets can be reduced compared to the nozzles used for small droplets. Moreover, at low printing densities, by forming a portion where the white pixels increase, even though the printing density increases, the non-spraying nozzles can be reduced. Compared with the droplet configuration where the non-spraying nozzles are not reduced, the number of simultaneously sprayed droplets can be effectively reduced, the influence of the spraying airflow can be suppressed, and the interference between the spraying airflows can be prevented. Thereby, the deviation of the landing position or the spraying bending of the sprayed droplets can be suppressed, and white stripes / black stripes, etc. at the seams of the print head can be suppressed.

[0095] The program executed by the image forming apparatus 100 of the present embodiment is a file in an installable or executable form and is provided by being recorded in a computer-readable recording medium such as a CD-ROM, a floppy disk (FD), a CD-R, a DVD (Digital Versatile Disk).

[0096] Alternatively, it may be configured to store the program executed by the image forming apparatus 100 of the present embodiment on a computer connected to a network such as the Internet, and provide it by downloading via the network. In addition, the program executed by the image forming apparatus 100 of the present embodiment may be provided or promulgated via a network such as the Internet.

[0097] In addition, it may be configured to pre-install the program executed by the image forming apparatus 100 of the present embodiment in a ROM or the like for providing.

[0098] The program executed by the image forming apparatus 100 of the present embodiment is a module configuration including the above respective parts (color separation data generation unit 211, ejection control unit 212). As actual hardware, the program is read and executed by a CPU (processor) from the above storage medium, and the above respective parts are loaded onto the main storage device, and the color separation data generation unit 211 and the ejection control unit 212 are generated on the main storage device.

[0099] (Second Embodiment)

[0100] Next, the second embodiment will be described.

[0101] The difference between the second embodiment and the first embodiment is that, compared with the first embodiment, the usage rate and usage range of small droplets and medium droplets are expanded, and the increase amount of white pixels is reduced. Hereinafter, in the description of the second embodiment, the description of the same parts as those of the first embodiment will be omitted, and the parts different from the first embodiment will be described.

[0102] Here, Figure 9 shown is a diagram of the relationship between the input level and the fall ratio according to the fifth embodiment, Figure 10 shown is a diagram of the relationship between the input level and the output level.

[0103] As Figure 9 shown, in the present embodiment, the ejection control unit 212 suppresses the usage rate of small droplets, and starts using medium droplets from 10% of the low input level. The ejection control unit 212 reduces the usage rate of small ink droplets from 10% of the input level at which medium droplets start to be used.

[0104] On the other hand, in the present embodiment, the ejection control unit 212 also expands the usage ratio of medium droplets, and starts reducing the usage rate of medium droplets from 20% of the input level at which large droplets start to be used. The ejection control unit 212 stops using medium droplets when the input level is 30%.

[0105] In addition, as Figure 10As shown, the ejection control unit 212 makes the ratio of the output level to the input level be a substantially linear relationship. Compared with the first embodiment, in this embodiment, the usage rate and the usage range of medium droplets are expanded, but the ratio of the output level to the input level is substantially linear, and the white pixels also monotonically decrease from the low gray level part to the high gray level part.

[0106] Regarding the influence on an image such as black stripes / white stripes caused by the deviation of the landing position or the bending of the ejection, it also varies depending on the liquid (ink) or the medium 40 used, the distance from the nozzle to the medium 40, the printing speed, and the like. By reducing the usage rate of small droplets or medium droplets, the influence of the deviation of the landing position or the bending of the ejection tends to be suppressed, but the granularity of the image tends to deteriorate. Therefore, it is necessary to achieve a balance according to the printing conditions.

[0107] Thus, the object of this embodiment is to improve the granularity of the low gray level region compared with the first embodiment.

[0108] In this way, according to this embodiment, compared with the first embodiment, the usage rate and the usage range of small droplets and medium droplets are expanded, and the increase amount of white pixels becomes smaller. However, by making the output level substantially linear with respect to the input level, white pixels exist outside 100% of the input level, the number of simultaneously ejected droplets can be suppressed, the influence of the ejection air flow can be suppressed, and the interference between ejection air flows can be prevented. As a result, the deviation of the landing position or the bending of the ejection of the ejected droplets can be suppressed, and white stripes / black stripes at the seams of the nozzle head can be suppressed.

[0109] (Third Embodiment)

[0110] Next, the third embodiment will be described. Hereinafter, in the description of the third embodiment, the description of the same parts as those in the first embodiment and the second embodiment is omitted, and the parts different from the first embodiment and the second embodiment will be described.

[0111] <Manufacturing Apparatus of Electrodes>

[0112] In the "apparatus for ejecting a liquid" according to the present invention, it further includes a manufacturing apparatus of electrodes and an electrochemical element. Hereinafter, the manufacturing apparatus of electrodes will be described.

[0113] Figure 11 Shown is a schematic diagram of an example of the manufacturing apparatus of electrodes according to the third embodiment. The manufacturing apparatus of electrodes is an apparatus for manufacturing an electrode including a layer having an electrode material by discharging a liquid composition using a nozzle head module including the liquid ejection head described in the first embodiment and the second embodiment.

[0114] <Forming Means of Layer Containing Electrode Material, Forming Process of Layer Containing Electrode Material>

[0115] Figure 11 The ejection means included in the manufacturing apparatus for the electrode shown is the nozzle module according to the above-described embodiment of the present invention. By ejecting the liquid composition from the ejection head included in the nozzle module, the liquid composition is applied to the object to form a liquid composition layer. As the object (hereinafter sometimes referred to as the "ejection object"), any object that forms a layer containing an electrode material may be used, and there is no particular limitation, and it can be appropriately selected according to the purpose. For example, as the object, an electrode substrate (current collector), an active material layer, a layer containing a solid electrode material, etc. can be cited. In addition, the object may be an electrode composite material layer containing an active material on the electrode substrate (current collector). In addition, as long as a layer having an electrode material can be formed on the ejection object, the ejection means and the ejection process may also be means and processes for directly ejecting the liquid composition to form a layer having an electrode material. In addition, the ejection means and the ejection process may also be means and processes for indirectly ejecting the liquid composition to form a layer having an electrode material.

[0116] <Other configurations, other processes>

[0117] As other configurations included in the manufacturing apparatus for the electrode composite material layer, there is no particular limitation as long as the effects of the present invention are not impaired, and they can be appropriately selected according to the purpose. In addition, as other processes included in the manufacturing method for the electrode composite material layer, there is no particular limitation as long as the effects of the present invention are not impaired, and they can be appropriately selected according to the purpose. For example, as the configurations and processes included in the manufacturing apparatus and the manufacturing method for the electrode composite material layer, a heating mechanism and a heating process, etc. can be cited.

[0118] <Heating mechanism, heating process>

[0119] The heating mechanism included in the manufacturing apparatus for the electrode composite material layer is a mechanism for heating the liquid composition ejected by the ejection means. In addition, the heating process included in the manufacturing method for the electrode composite material layer is a process for heating the liquid composition ejected in the ejection process. By heating the liquid composition, the liquid composition layer can be dried.

[0120] <Configuration for forming a layer containing an electrode material by direct ejection of a liquid composition>

[0121] Here, as an example of the manufacturing apparatus for the electrode, a manufacturing apparatus for an electrode that forms an electrode composite material layer containing an active material on an electrode substrate (current collector) will be described. As Figure 11As shown, the manufacturing apparatus for an electrode includes a jetting process section 280, which includes a process of applying a liquid composition onto a printing base material 704 having an object to be jetted to form a liquid composition layer, and a heating process section 130, which includes a heating process of heating the liquid composition layer to obtain an electrode composite material layer.

[0122] The manufacturing apparatus for an electrode includes a conveyance section 705 that conveys the printing base material 704. The conveyance section 705 conveys the printing base material 704 in the order of the jetting process section 280 and the heating process section 130 at a preset speed. As a method for manufacturing the printing base material 704, which is an object to be jetted such as an active material layer, there is no particular limitation, and a known method can be appropriately selected. The jetting process section 280 includes a liquid jet head 122 that implements the application process of applying the liquid composition onto the printing base material 704, a storage container 281b that stores the liquid composition 707, and a supply pipe 281c that supplies the liquid composition 707 stored in the storage container 281b to the liquid jet head 122.

[0123] In the jetting process section 280, the liquid composition 707 is jetted from the liquid jet head 122, and the liquid composition 707 is applied onto the printing base material 704 to form a thin-film-like liquid composition layer. In addition, the storage container 281b may be configured to be integrated with the manufacturing apparatus for the electrode composite material layer, or may be configured to be removable from the manufacturing apparatus for the electrode composite material layer. Further, the storage container 281b may be a storage container integrated with the manufacturing apparatus for the electrode composite material layer, or may be a container for adding to a storage container that can be removed from the manufacturing apparatus for the electrode composite material layer.

[0124] The storage container 281b and the supply pipe 281c can be arbitrarily selected as long as they can stably store and supply the liquid composition 707.

[0125] In the heating process section 130, a solvent removal process is performed to heat and remove the solvent remaining in the liquid composition layer. Specifically, the solvent remaining in the liquid composition layer is dried by heating with the heating device 703 of the heating process section 130 to remove the solvent from the liquid composition layer. Thereby, an electrode composite material layer is formed. In addition, the solvent removal process in the heating process section 130 may also be performed under reduced pressure.

[0126] As the heating device 703, there is no particular limitation, and it can be appropriately selected according to the purpose. For example, as the heating device 703, substrate heating, IR heaters, hot air heaters, etc. can be cited. In addition, the heating device 703 can also be a device formed by combining at least two of substrate heating, IR heaters, and hot air heaters. In addition, regarding the heating temperature and heating time, they can be appropriately selected according to the boiling point of the solvent contained in the liquid composition 707 or the film thickness to be formed.

[0127] By using the manufacturing device for an electrode according to an embodiment of the present invention, a liquid composition can be ejected onto a target site of an ejection object. The electrode composite material layer can be preferably used, for example, as part of the constitution of an electrochemical element. As the constitution other than the electrode composite material layer in the electrochemical element, there is no particular limitation, and publicly known constitutions can be appropriately selected. For example, as the constitution other than the electrode composite material layer, a positive electrode, a negative electrode, a separator, etc. can be cited.

[0128] Furthermore, in the present application, the "device for ejecting a liquid" is a device that includes a liquid ejection head 122 or a liquid ejection unit and drives the liquid ejection head 122 to eject a liquid. In the device for ejecting a liquid, it includes not only a device that can eject a liquid onto an object to which the liquid can adhere, but also a device that ejects a liquid into the air or a liquid.

[0129] This "device for ejecting a liquid" can also include mechanisms for supplying, transporting, and discharging paper to an object to which the liquid can adhere, as well as a pre-treatment device, a post-treatment device, etc.

[0130] For example, as the "device for ejecting a liquid", there are an image forming device that ejects ink liquid to form an image on paper, and a three-dimensional modeling device (3D modeling device) that ejects a modeling liquid onto a powder layer in which a powder is formed in a layer shape in order to model a three-dimensional object (3D object).

[0131] In addition, the "device for ejecting a liquid" is not limited to making meaningful images such as characters and graphics visible by the ejected liquid. For example, it also includes forming a pattern that has no meaning itself, and things for modeling a three-dimensional image.

[0132] The above-mentioned "substance to which a liquid can adhere" refers to a substance to which a liquid can adhere at least temporarily, and refers to a substance that adheres and penetrates after adhesion. As specific examples, they can be recording media such as paper, recording paper, recording sheets, films, cloth, etc., electronic parts such as electronic substrates and piezoelectric elements, and media such as powder layers (powder layers), organ models, and inspection parts, and as long as there is no particular limitation, it includes all substances to which a liquid can adhere.

[0133] The material of the above-mentioned "substance capable of adhering to liquid" only needs to be such that liquids such as paper, silk, fiber, cloth, leather, metal, plastic, glass, wood, and ceramics can adhere to it even temporarily.

[0134] In addition, the "liquid" only needs to be a liquid having a viscosity and surface tension that can be ejected from the liquid ejection head 122, and there is no particular limitation, but preferably has a viscosity of 30 MPa·s or less at normal temperature and pressure or under heating and cooling. More specifically, it includes solvents such as water or organic solvents, colorants such as dyes and pigments, functional imparting materials such as polymerizable compounds, resins, and surfactants, bio-compatible materials such as DNA, amino acids, proteins, and calcium, and edible materials such as natural pigments, etc. Solutions, suspensions, latexes, etc. of these can be used for applications such as ink liquids for inkjet, surface treatment liquids, constituent elements of electronic components and light-emitting elements, and liquids for forming patterns of electronic circuit resist layers, and material liquids for three-dimensional modeling, etc.

[0135] In addition, the "device for ejecting liquid" has a device for relative movement of the liquid ejection head 122 and the substance capable of adhering to liquid, but is not limited thereto. As specific examples, it includes a serial device for moving the liquid ejection head 122, a line type device for not moving the liquid ejection head 122, etc.

[0136] In addition, as the "liquid ejection device", there is also a treatment liquid coating device for ejecting a treatment liquid onto the surface of paper for the purpose of modifying the surface of the paper, etc., and an ejection granulation device for granulating fine particles of a raw material by ejecting a composition liquid in which the raw material is dispersed into a solution through a nozzle, etc.

[0137] Embodiments of the present invention are described as follows, for example.

[0138] <1>A liquid ejection head that selectively ejects two or more types of droplets with different ejection droplet amounts from a nozzle to perform gray-scale expression of a concentration corresponding to an input gray-scale value, characterized by including: an ejection control unit that performs control such that only the largest droplet among the two or more types of droplets is ejected from the nozzle in the high gray-scale portion of the input gray-scale value, and includes a portion where the number of nozzles that do not eject among all the nozzles increases non-monotonically decreasingly from the low gray-scale portion to the high gray-scale portion of the input gray-scale value.

[0139] <2>The liquid ejection head according to <1>, characterized in that the control performed by the ejection control unit is such that as the input gray-scale value increases, the ratio of the ejection droplet amount does not decrease.

[0140] <3>The liquid ejection head according to <1> or <2>, characterized in that: the ejection control unit performs control so that the smallest droplet among the two or more types of droplets is ejected only when the input gray value is 13% or less.

[0141] <4>The liquid ejection head according to any one of <1> to <3>, characterized in that: the ejection control unit performs control so that the smallest droplet among the two or more types of droplets is ejected only when the input gray value is 10% or less.

[0142] <5>The liquid ejection head according to <1> or <2>, characterized in that: three or more types of droplets with different ejection droplet amounts are selectively ejected from the nozzle, and the ejection control unit performs control so that the second smallest droplet among the three or more types of droplets is ejected when the input gray value is 15% or less.

[0143] <6>The liquid ejection head according to <1> or <2>, characterized in that: the control performed by the ejection control unit is such that, for a portion where the number of nozzles that do not eject among all the nozzles decreases from the low gray portion to the high gray portion of the input gray value, there is at least one place where it is 20% or less of the input gray value.

[0144] <7>The liquid ejection head according to <1> or <2>, characterized in that: the control performed by the ejection control unit is such that, for a portion where the number of nozzles that do not eject among all the nozzles decreases from the low gray portion to the high gray portion of the input gray value, at least two or more types of droplets with different ejection sizes are ejected.

[0145] <8>A liquid ejection unit, characterized by comprising: the liquid ejection head according to any one of <1> to <7>, and at least any one of a printhead tank, a carriage, a supply mechanism, a maintenance and recovery mechanism, and a main scanning movement mechanism.

[0146] <9>A device for ejecting a liquid, characterized by comprising: the liquid ejection head according to any one of <1> to <7>, and a control unit that drives the liquid ejection head to eject the liquid.

[0147] <10>A liquid ejection method in a liquid ejection head that selectively ejects two or more types of droplets with different ejection droplet amounts to perform gray scale expression of a concentration corresponding to an input gray value, characterized by comprising: an ejection control step that performs control so that only the largest droplet among the two or more types of droplets is ejected from the nozzle in the high gray portion of the input gray value, and includes a portion where the number of nozzles that do not eject among all the nozzles increases non-monotonically from the low gray portion to the high gray portion of the input gray value.

[0148] <11>A computer program product, characterized in that: a computer for controlling a liquid ejection head is used as an ejection control unit to perform control such that only the largest droplet among the two or more types of droplets is ejected from the nozzle in a high gray level portion of the input gray level value, and it includes a portion where the number of nozzles that do not eject among all the nozzles increases non-monotonically decreasingly from a low gray level portion to a high gray level portion of the input gray level value, and the liquid ejection head selectively ejects two or more types of droplets with different ejection droplet amounts from the nozzle to perform gray level expression of a density corresponding to the input gray level value.

Claims

1. A liquid ejection head for selectively ejecting two or more liquid droplets of different ejection droplet amounts from a nozzle to perform grayscale expression of a concentration corresponding to an input grayscale value, characterized in that include: An ejection control unit controls so that only the largest droplet among the two or more droplets is ejected from the nozzle in the high grayscale portion of the input grayscale value, and includes a portion in which the number of the nozzles that are not ejected among all the nozzles does not increase monotonically from the low grayscale portion to the high grayscale portion of the input grayscale value.

2. The liquid ejecting head according to claim 1, wherein: The ejection control unit performs control so as not to reduce the ratio of the ejected droplet amount as the input grayscale value increases.

3. The liquid ejecting head according to claim 1, wherein: The ejection control unit performs control so that the smallest droplet among the two or more droplets is ejected only when the input grayscale value is 13% or less.

4. The liquid ejecting head according to claim 1, wherein: The ejection control unit performs control so that the smallest droplet among the two or more types of droplets is ejected only when the value of the smallest droplet is 10% or less of the input grayscale value.

5. The liquid ejecting head according to claim 1, wherein: selectively ejecting three or more types of droplets having different ejection droplet amounts from the nozzle, The ejection control unit performs control so that the second smallest droplet among the three or more types of droplets is ejected when the droplet value is 15% or less of the input grayscale value.

6. The liquid ejecting head according to claim 1, wherein: The ejection control unit performs control so that, among all the nozzles, at least one portion where the number of the nozzles not ejecting decreases from a low grayscale portion to a high grayscale portion of the input grayscale value exists at or below 20% of the input grayscale value.

7. The liquid ejecting head according to claim 1, wherein: The ejection control unit controls to eject at least two or more types of droplets of different sizes in a portion where the number of the non-ejecting nozzles among all the nozzles decreases from a low grayscale portion to a high grayscale portion of the input grayscale value.

8. A liquid spraying unit, characterized in that include: The liquid ejecting head according to any one of claims 1 to 7, and At least one of the head tank, the carriage, the supply mechanism, the maintenance recovery mechanism, and the main scanning movement mechanism.

9. A device for spraying liquid, characterized in that include: The liquid ejecting head according to any one of claims 1 to 7, and A control unit drives the liquid ejecting head to eject liquid.

10. A liquid ejection method in a liquid ejection head for selectively ejecting two or more liquid droplets of different ejection droplet amounts from a nozzle to perform grayscale expression of a concentration corresponding to an input grayscale value, characterized in that include: An ejection control process, which controls so that only the largest droplet among the two or more droplets is ejected from the nozzle in the high grayscale portion of the input grayscale value, and includes a portion in which the number of the nozzles that are not ejected among all the nozzles increases non-monotonically from the low grayscale portion to the high grayscale portion of the input grayscale value.

11. A computer program product, characterized in that: A computer for controlling the liquid ejection head is used as an ejection control unit to perform control so that only the largest droplet among the two or more droplets is ejected from the nozzle in the high grayscale portion of the input grayscale value, and the number of the nozzles that are not ejected among all the nozzles does not increase monotonically from the low grayscale portion to the high grayscale portion of the input grayscale value, The liquid ejecting head selectively ejects two or more types of liquid droplets having different ejection droplet amounts from a nozzle to perform grayscale expression with a concentration corresponding to an input grayscale value.

Images