JP6977637B2 - Image processing device, liquid ejection device, image processing method, program - Google Patents

Description

The present invention relates to an image processing device, a device for discharging a liquid, an image processing method, and a program.

In order to output an input image with a device that outputs an image using a liquid discharge head, for example, a combination of multiple dots of different sizes is combined with the input image to generate halftone image data that expresses gradation. Halftone processing is performed.

Conventionally, when forming an image by the electrophotographic method, a highlight pattern is created with sufficient intervals so that the gradation is not crushed even if dot gain is generated, and dots are collected around the highlight pattern as a core. A method of growing halftone dots is known (Patent Document 1).

Japanese Unexamined Patent Publication No. 2002-337401

However, in the device for discharging the liquid, the landing position may be displaced by, for example, several tens of μm to 100 μm due to the bending of the liquid discharge or the fluctuation of the mechanism portion due to the main / sub-scanning operation. Therefore, even if you try to form a halftone dot by solidifying a droplet around the highlight dot as in the past, the halftone dot can be larger or smaller than the target due to the effect of the landing position shift, so halftone. There is a problem that the gradation characteristics change.

The present invention has been made in view of the above problems, and an object of the present invention is to be able to suppress a change in halftone gradation characteristics even if a dot position shift occurs.

In order to solve the above problems, the image processing apparatus according to the present invention is
An image processing device that performs halftone processing that expresses gradation by combining dots of multiple sizes.
In the gradation region less than a predetermined value, a pattern is formed by dispersing and arranging the first dots having a resolution and a dot size in which at least a part of the dots does not overlap even if the dot position shift occurs.
In the gradation region of a predetermined value or more, a halftone process is performed in which the second dots having a size that maintains at least a part of the overlap between the dots even if the dot position shift occurs are distributed so as to fill the voids of the pattern. Equipped with means ,
The liquid constituting the first dot is designated to be composed of a liquid having a lower concentration than the liquid constituting the second dot .

According to the present invention, halftone gradation can be maintained even if the dot position shift occurs.

It is a plane explanatory view of the mechanism part as an example of the apparatus which discharges a liquid which concerns on this invention. Similarly, it is a side view of the main part. It is sectional drawing explanatory drawing of the direction orthogonal to the nozzle arrangement direction (the liquid chamber longitudinal direction) of an example of a liquid discharge head. Similarly, it is a cross-sectional explanatory view in the nozzle arrangement direction (liquid chamber short side direction). It is a block explanatory drawing of the control part of the apparatus. It is a block explanatory drawing of an example of the image processing apparatus which concerns on this invention. It is a block explanatory diagram provided for the explanation of the example which executes the halftone processing which concerns on the image processing apparatus side. It is a block explanatory diagram provided for the explanation of the example which executes the halftone processing which concerns on the printing apparatus side. It is explanatory drawing which provides the explanation of the image unevenness in the apparatus which discharges a liquid. It is explanatory drawing of the head arrangement of the joint composition. It is explanatory drawing of the phase shift of the head of the same connection structure. It is explanatory drawing of the texture unevenness due to the phase shift of the head of the same connection structure. It is explanatory drawing which provides the explanation of the landing position deviation of a droplet and the dot size (dot diameter). It is explanatory drawing of the recording resolution and the position shift of a dot which are used for the explanation of construction of an anchor pattern. It is explanatory drawing which provides the explanation of an example of a halftone process. It is explanatory drawing which provides the explanation of the threshold mask of a small drop and the formation of a pattern. It is explanatory drawing which provides the explanation of the formation of the threshold mask of a middle drop and the pattern which follows FIG. It is explanatory drawing which provides the explanation of the formation of the threshold mask of a large drop and the pattern following FIG.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. First, an example of a device for discharging a liquid that outputs image data generated by the image processing according to the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a plan explanatory view of a mechanism portion of a printing device as a device for discharging the liquid, and FIG. 2 is a side surface explanatory view of the main part.

The printing device 100 is a serial type device. The carriage 105 is movably held in the main scanning direction by a guide mechanism such as a main guide member 102 and a slave guide plate 103 spanning the left and right side plates 101A and 101B.

The carriage 105 is equipped with three liquid discharge units 110 (110a to 110c). The liquid discharge unit 110 is configured by integrating a liquid discharge head (head) 111 as a liquid discharge means and a sub tank 112 that supplies liquid to the head 111.

On the main body side of the apparatus, a cartridge holder 121 is arranged in which a plurality of main tanks (liquid cartridges) 120 accommodating liquids of each color are replaceably mounted. Liquids of each color are supplied from the main tank 120 mounted on the cartridge holder 121 to the head 111 of each liquid discharge unit 110 via a liquid path 123 composed of supply tubes of each color by a liquid feed pump or the like.

On the other hand, in order to transport the sheet material 130 in the transport direction, the transport means 140 that attracts the sheet material 130 and transports the sheet material 130 toward the head 111 is provided.

The transporting means 140 provides a sheet material 130 via a transport roller 141, a pressure roller 142 that is pressurized and contacted with the transport roller 141, a platen member 143 facing the head 111, and a suction hole 143 a of the platen member 143. It is composed of a suction mechanism unit 144 or the like for suction. Although the suction hole 143a is partially shown in the figure, it is arranged on the entire platen member 143.

Further, a maintenance / recovery mechanism 150 for performing maintenance / recovery (maintenance) of the head 111 is arranged on one side of the carriage 105 in the main scanning direction.

The maintenance / recovery mechanism 150 includes, for example, a cap 151 for capping the nozzle surface 111a of the head 111, and a wiping unit 152 including a web 154 for wiping the nozzle surface 111a and a wiper member 155. The wiping unit 152 is arranged on the main frame 156.

In this printing apparatus 100, the sheet material 130 is conveyed in the conveying direction while being adsorbed on the platen member 143 by the conveying roller 141 and the pressure roller 142.

Therefore, by driving the head 111 in response to the print signal while moving the carriage 105 in the main scanning direction, a liquid of a required color is discharged to the stopped sheet material 130 to print one line, and the sheet is printed. After transporting a predetermined amount of the material 130, printing of the next line is repeated to print, and the sheet material 130 is discharged.

Next, an example of the liquid discharge head will be described with reference to FIGS. 3 and 4. FIG. 3 is a cross-sectional explanatory view in a direction orthogonal to the nozzle arrangement direction of the head (liquid chamber longitudinal direction), and FIG. 4 is a cross-sectional explanatory view in the nozzle arrangement direction (liquid chamber short side direction).

The liquid discharge head 111 joins the nozzle plate 1, the flow path plate 2, and the diaphragm member 3. A piezoelectric actuator 11 that displaces the diaphragm member 3 and a frame member 20 as a common flow path member are provided.

As a result, a liquid supply that also serves as a fluid resistance unit that supplies liquid to the individual liquid chambers (also referred to as pressure chambers, pressurizing chambers, etc.) 6 and the individual liquid chambers 6 that lead to the plurality of nozzles 4 that eject droplets. A passage 7 and a liquid introduction portion 8 leading to the liquid supply passage 7 are formed. The adjacent individual liquid chambers 6 are separated by a partition wall 6A in the nozzle arrangement direction.

Then, the liquid is supplied from the common flow path 10 as the common flow path of the frame member 20 to the plurality of individual liquid chambers 6 through the liquid introduction section 8 and the liquid supply path 7 through the filter section 9 formed in the diaphragm member 3. ..

The piezoelectric actuator 11 is arranged on the side opposite to the individual liquid chamber 6 with the deformable vibration region 30 forming the wall surface of the individual liquid chamber 6 of the diaphragm member 3 interposed therebetween.

The piezoelectric actuator 11 has a plurality of laminated piezoelectric members 12 joined on the base member 13. The piezoelectric member 12 is grooved by half-cut dicing to form a piezoelectric element 12A as a columnar pressure generating element that gives a drive waveform and a support column 12B in a comb-teeth shape at predetermined intervals.

Then, the piezoelectric element 12A is joined to the island-shaped convex portion 3a formed in the vibration region 30 of the diaphragm member 3. Further, the support column 12B is joined to the convex portion 3b of the diaphragm member 3.

The piezoelectric member 12 is formed by alternately laminating a piezoelectric layer and an internal electrode, and the internal electrodes are each drawn out to the end face to provide an external electrode, and it is possible to give a drive waveform to the external electrode of the piezoelectric element 12A. An FPC 15 as a flexible wiring board having flexibility is connected.

The frame member 20 is formed with a common flow path 10 to which liquid is supplied from a head tank or a liquid cartridge.

In the liquid discharge head 111, for example, by lowering the voltage applied to the piezoelectric element 12A from the intermediate potential Ve, the piezoelectric element 12A contracts, the vibration region 30 of the vibrating plate member 3 decreases, and the volume of the individual liquid chamber 6 increases. By expanding, the liquid flows into the individual liquid chamber 6.

After that, the voltage applied to the piezoelectric element 12A is increased to extend the piezoelectric element 12A in the stacking direction, the vibration region 30 of the diaphragm member 3 is deformed in the nozzle 4 direction, and the volume of the individual liquid chamber 6 is contracted. As a result, the liquid in the individual liquid chamber 6 is pressurized, and the liquid is discharged (sprayed) from the nozzle 4.

Then, by returning the voltage applied to the piezoelectric element 12A to the reference potential, the vibration region 30 of the vibrating plate member 3 is restored to the initial position, the individual liquid chamber 6 expands, and a negative pressure is generated. Therefore, the common flow path 10 The individual liquid chamber 6 is filled with the liquid through the liquid supply path 7. Therefore, after the vibration of the meniscus surface of the nozzle 4 is attenuated and stabilized, the operation for the next ejection is started.

Next, the outline of the control unit of this printing apparatus will be described with reference to FIG. Note that FIG. 5 is a block explanatory diagram of the control unit.

The control unit 500 temporarily stores the CPU 501 that controls the entire device, the ROM 502 that stores fixed data such as various programs including a program for executing the process according to the present invention executed by the CPU 501, and image data and the like. It is provided with a main control unit 500A including a RAM 503 to be used.

Further, the control unit 500 has a rewritable non-volatile memory (NVRAM) 504 for holding data even while the power of the device is cut off, and image processing for performing various signal processing, sorting, etc. on the image data. It also includes an image processing unit 505 that processes input / output signals for controlling the entire device.

Further, the control unit 500 includes a head drive control unit 508 including a head control unit for driving and controlling the head 111 and a drive waveform generation unit. The head drive control unit 508 drives and controls the head 111 via a head driver (driver IC) 509 provided on the carriage 105 side.

Further, the control unit 500 includes a carriage drive unit 510 that drives the main scanning motor 551 that moves and scans the carriage 105, and a transfer system drive unit 511 that drives the feed motor 552 that drives the transfer roller 141 and the suction mechanism unit 144. I have.

Further, the control unit 500 includes a supply system drive unit 512 that drives a liquid supply pump unit 553 that transfers liquid from the liquid cartridge 120 to each head 111 side, and a maintenance drive unit 515 that drives the maintenance / recovery mechanism 150. I have.

Further, the control unit 500 includes an I / O unit 513. The I / O unit 513 acquires the reading signal from the reading sensor 560 and the information from various sensor groups 570, extracts the information necessary for controlling the device, and uses it for various controls.

Further, an operation panel 514 for inputting and displaying information necessary for this device is connected to the control unit 500.

Further, the control unit 500 includes an I / F 506 for transmitting / receiving data and signals to / from the printer driver 421 of the host 400 such as an information processing device such as a personal computer, an image reading device, and an imaging device.

Then, the CPU 501 of the control unit 500 reads out and analyzes the print data in the receive buffer included in the I / F 506, and the image processing unit 505 performs necessary image processing, data rearrangement processing, and the like, and this image data. Is transferred to the head driver 509 via the head drive control unit 508.

The head drive control unit 508 transfers the image data as serial data, and outputs the transfer clock, latch signal, control signal, etc. necessary for transferring the image data and confirming the transfer to the head driver 509.

The head drive control unit 508 includes a drive waveform generation unit including a D / A converter that D / A-converts waveform data of the drive waveform read from the ROM 502, a voltage amplifier, a current amplifier, and the like. Then, a drive waveform composed of one drive pulse or a plurality of drive pulses is generated and output to the head driver 509.

The head driver 509 selects a drive pulse constituting a drive waveform given by the head drive control unit 508 based on image data corresponding to one line of the head 111 serially input to the piezoelectric element 12A of the head 111. Give to. This drives the head 111. At this time, by selecting a part or all of the pulse constituting the drive waveform or all or part of the waveform element forming the pulse, for example, a large drop, a medium drop, a small drop, or the like can be of a size. You can hit different dots.

Next, an image processing device equipped with a program for causing a computer to execute image processing according to the present invention for outputting a printed image by the above printing device will be described with reference to the block explanatory diagram of FIG.

In the image processing device 400, the CPU 401 and various ROM 402s and RAM 403s as memory means are connected by a bus line. A storage device 406, an input device 404 such as a mouse or keyboard, a monitor 405, or the like are connected to this bus line via a predetermined interface, and communication is performed with a network such as the Internet or an external device such as USB. A predetermined interface (external I / F) 407 to be performed is connected.

The storage device 406 of the image processing device 400 stores an image processing program including a program for executing the processing according to the present invention. This image processing program may be one that operates on a predetermined OS, or may be a part of specific application software.

Here, an example of executing the halftone processing (image processing) according to the present invention by the program on the image processing apparatus 400 side will be described with reference to the functional block diagram of FIG. 7.

The printer driver 421 including a program for causing the CPU 401 to execute the image processing according to the present invention on the image processing device 400 (PC) side records the image data 410 given by application software or the like from the color space for monitor display (image). CMM (Color Management Module) processing unit 412 that performs conversion to a color space for the forming device) (RGB color system → CMY color system), BG / UCR (black) that produces black / removes undercolor from CMY values. generation / Under Color Removal) Characteristics of the processing unit 413, the total amount control unit 414 that corrects the CMYK signal according to the maximum total amount value of the recording color material that can be printed by the printing device 100 with respect to the CMYK signal that is the recording control signal, and the printing device 100. Γ correction unit 415 that performs input / output correction that reflects the user's preference, zooming processing that performs enlargement processing according to the resolution of the printing device 100, and replacement of image data with a pattern arrangement of dots ejected from the printing device 100. The halftone processing unit 416 includes a rasterizing unit 417 that divides the dot pattern data, which is the print image data obtained in the halftone processing, into data for each scan, and further develops the data according to the position of each nozzle for recording. , The output 418 of the rasterizing unit 417 is sent to the printing apparatus 100.

A part of such image processing can also be executed on the printing apparatus 100 side. This example will be described with reference to the functional block diagram of FIG.

The printer driver 421 on the image processing apparatus 400 (PC) side sends the image data generated by performing the above-mentioned processing up to γ correction to the printing apparatus 100.

On the other hand, the control unit 500 of the printing apparatus 100 constitutes a halftone processing unit 616 and a rasterizing unit 617, and supplies the output 618 of the rasterizing unit 617 to the head drive control unit 508. In this case, the program according to the present invention is stored in the ROM 502.

The image processing (halftone processing) according to the present invention can be applied to any of the configurations shown in FIGS. 7 and 8.

Next, the image unevenness in the device for discharging the liquid will be described with reference to FIGS. 9 to 12. FIG. 9 is an explanatory diagram of image unevenness when multipath recording is performed. 10 is an explanatory diagram of the head arrangement of the joint configuration, FIG. 11 is an explanatory diagram of the phase shift of the heads of the same joint configuration, and FIG. 12 is an explanatory diagram of texture unevenness due to the phase shift of the heads of the same joint configuration.

When image is created by the liquid ejection method, image unevenness may occur due to the ejection bending of droplets and the variation in the transfer control of the sheet material. This image unevenness can be reduced by performing so-called multi-pass recording in which a unit area is overlaid using different nozzles in a plurality of scans.

However, in multipath recording, the printing time increases as the number of scans increases, and the productivity decreases. Further, when a large head unit having a "joint configuration" in which a plurality of heads of the same color are arranged is configured, in addition to the image unevenness as described above, unevenness due to a phase shift between the heads occurs.

Therefore, even in multi-pass recording with a small number of scans, it is required to reduce image unevenness while suppressing deterioration of graininess.

In this case, as described above, when the droplets are compacted around the highlight dots to form halftone dots, the halftone dots become larger or smaller than the target due to the influence of the landing position shift of the droplets. , Halftone gradation cannot be maintained. Further, since the number of printed lines (almost the image resolution) is fixed by the highlight dot pattern, the graininess is deteriorated.

For example, as shown in FIG. 9, when multi-pass recording is performed, a dot short (overlap) occurs in the vertical direction in the second scan, and a dot short occurs in the vertical direction even in the third scan, and the third scan and the like. A gap is generated at the 4th time.

That is, when the number of scans is small, the landing position deviation (deviation in the vertical direction in FIG. 9) cannot be dispersed and a gap is generated as in the fourth and eighth scans. When this occurs uniformly in the main scanning direction (looks like banding), or in synchronization with head swing fluctuation (rolling or yawing), deviations may occur and disappear repeatedly like a sine curve. (In this case, it looks like a moire pattern).

Further, as shown in FIG. 10, when the heads HA to HC that discharge the same color are arranged in the vertical direction (sheet material feed direction) in a "joint configuration", the heads are discharged due to a difference between the head arrangement portion and the trigger timing. The dot positions formed by the droplets change as shown in FIG. 11 (the landing phase shift occurs).

Due to this phase shift of landing, texture unevenness as shown in FIG. 12 occurs. Texture unevenness caused by this phase shift does not always occur repeatedly at a fixed position, and the occurrence site changes due to the transfer shift of the sheet material (shift in the sub-scanning direction) or the like.

In this case, the anti-phase method of shifting the dots to the anti-phase of the phase shift has an inconvenience that a new texture is generated even if the phase is slightly deviated from the assumed position.

Therefore, in the present embodiment, a dot having a size that maintains at least a part of overlap between the dots even if the landing position shift (dot position shift) occurs is referred to as a large dot (second dot). Further, for small dots and medium dots (these are referred to as "first dots") whose size is smaller than that of the large dots, the resolution at which at least a part of the dots does not overlap even if the dot position shift occurs is calculated.

Then, from the highlight part to the middle part, that is, in the gradation region less than a predetermined value, even if the dot position shift occurs, at least a part of the dots does not overlap, and the first dot of the resolution and the dot size is dispersed. Arrange them to form a gradation pattern (this is called an "anchor pattern"). A threshold mask in which a threshold is arranged, for example, an FM mask is used to form this anchor pattern.

Further, from the middle portion to the shadow portion, that is, in the gradation region of a predetermined value or more, large dots (second dots) are distributed so as to fill the voids of the anchor pattern. For the arrangement of the large dots, a threshold mask in which the thresholds are arranged so as to disperse the large dots so as to fill the voids of the anchor pattern, for example, an FM mask is used.

At this time, it is preferable to use an FM mask in which a threshold value is arranged so as to have a high frequency characteristic (blue noise characteristic) in both the anchor pattern and the composite pattern in which the anchor pattern and the large dot are combined.

That is, in the present embodiment, when performing halftone processing for expressing gradation by combining dots of a plurality of sizes, an anchor constructed with a recording resolution having a margin for landing position error (dot position deviation). When a dot with a size that includes a mask that forms a pattern and has a sufficient margin for landing position error is defined as a large dot, small and medium dots that are smaller than the large dot are distributed and arranged according to the anchor pattern. , The large dots themselves are distributed and arranged so as to fill the voids of the anchor pattern, and the thresholds are arranged so that the dispersion tendency of the anchor pattern and the composite pattern of the anchor pattern and the large dots has high frequency characteristics. Do the processing using.

In this case, even if the head has the above-mentioned connection configuration, the gradation density is maintained by forming an anchor pattern with a gap in which the dots do not overlap even if the landing position shifts due to the phase shift of the landing. Texture unevenness can be suppressed.

Here, the landing position shift (dot position shift) and the dot size (dot diameter) of the droplet will be described with reference to FIG. FIG. 13 is an explanatory diagram provided for the same explanation.

As shown in FIG. 13A, when dots are arranged at a resolution (recording resolution) of 900 dpi × 600 dpi, they can be filled with dots D1 if there is no landing position deviation.

However, if there is a landing position shift, for example, as shown in FIG. 13B, a gap S is generated at the dot D1 having a diameter of 70 μm. On the other hand, as shown in FIG. 13 (c), when the dots D2 having a diameter of 105 μm are used, even if the landing position shift occurs, they can be overlapped without forming a gap. At this time, the dot D2 becomes a large dot having a sufficient margin for maintaining the overlap between the dots with respect to the landing position deviation.

Next, the construction of the anchor pattern will be described with reference to FIG. FIG. 14 is an explanatory diagram of dot position deviation with respect to the recording resolution used for the same explanation.

As shown in FIG. 14, the resolution and the dot diameter are calculated so that the dot position does not reverse (superimpose) even if the dot position shift occurs due to a fluctuation factor from the landing accuracy of the droplet. Here, the dot diameter of the small droplet is 49 μm, and the dot diameter of the medium droplet is 63 μm.

Then, an anchor pattern is constructed in which the dots are arranged at a resolution and a dot diameter (dot size) at which at least a part of the dots do not overlap even if the dot position shift occurs.

Next, an example of halftone processing will be described with reference to FIG. FIG. 15 is an explanatory diagram provided for the same explanation.

For the gradation from the highlight part to the middle part (gradation area less than the predetermined value), the anchor pattern is used, and as shown in FIGS. 15A and 15B, small dots (“small”) are used. Notation) to medium dots (denoted as "middle") are distributed. Italicized characters indicate that they are placed later.

Here, FIG. 15B is the final arrangement in the anchor pattern. That is, the anchor patterns are arranged so as to be sequentially replaced from small dots (small dots) to large dots (medium dots).

In forming this anchor pattern, dots with a size smaller than the large dot (second dot) (first dot) should be specified to form a dot using a liquid with a lower concentration than the liquid of the large dot. You can also.

Then, for the gradation from the middle portion to the shadow portion (gradation region of a predetermined value or more), as shown in FIG. 15 (c), large dots are distributed and arranged so as to fill the voids of the anchor pattern, and finally. Is replaced with large dots, as shown in FIG. 15 (d).

Next, an example of forming an FM mask and an anchor pattern for small droplets / medium droplets / large droplets will be described with reference to FIGS. 16 to 18. 16 to 18 are explanatory views provided for the same explanation.

Generally, the landing position shift (dot position shift) is about half of the resolution pitch, but in the anchor pattern of the present embodiment, most of the dots are shifted even if the landing shifts up to 1.5 pixel pitch. Is set to a non-overlapping interval, that is, an interval in which the dots do not substantially overlap (including the case where the dots do not overlap at all). However, it is sufficient that at least a part of the dots does not overlap.

16 (a) is an example of an anchor pattern of a small drop (small dot), FIG. 16 (b) is an example of an anchor pattern of a medium drop (medium dot), and FIG. 16 (c) is an anchor of a large drop (large dot). This is an example of a pattern.

FIG. 16A shows an example of an FM mask threshold table as a threshold mask for arranging small droplets (small dots). In the present embodiment, small dots are distributed and arranged at a resolution that does not overlap even if the dot position shift occurs in the gradation values 1 to 44, for example, a resolution 1.5 times the resolution of the apparatus (see FIG. 16B). do.

As a result, for example, at the gradation value 44, an anchor pattern of small droplets as shown in FIG. 16B is created. After that, as shown in FIG. 16 (c), the process shifts to the creation of an anchor pattern including small droplets to medium droplets.

FIG. 17A shows an example of an FM mask threshold table as a threshold mask for arranging middle drops (middle dots). In the present embodiment, the gradation values 45 to 74 are distributed and arranged with medium dots at a resolution that does not overlap even if the dot position shift occurs like the small droplets, for example, a resolution 1.5 times the resolution of the device (small droplets). It has the same anchor pattern as the distributed arrangement of.).

As a result, for example, at the gradation value 74, as shown in FIG. 17 (b), an anchor pattern of a middle drop in which all the small drops are replaced with the middle drop is created. After that, as shown in FIG. 17 (c), the process shifts to the creation of an anchor pattern containing medium to large droplets.

FIG. 18A shows an example of an FM mask threshold table as a threshold mask for arranging large droplets (large dots). In the present embodiment, when the gradation value is 75 or more, large dots are dispersedly arranged to fill the voids of the anchor pattern up to the middle drop.

As a result, as shown in FIGS. 18 (b) and 18 (c), the voids of the anchor pattern up to the middle drop are sequentially filled with large dots, and finally the large dots become solid.

In this way, even if the landing position shift (dot position shift) occurs, an anchor pattern is formed from small dots to medium dots, and the minimum gradation characteristics from the highlight portion to the middle portion are secured.

Then, by distributing and arranging large dots having a size larger than necessary and sufficient in terms of recording resolution at the pixel positions where the dots are not formed, the gaps generated by the landing position shift are filled with the margin of the dot diameter.

At this time, since the large dots with the misalignment are partially superimposed on the anchor pattern, the excessive dot size becomes inconspicuous and the deterioration of the graininess can be suppressed. And since the pattern disperses the dots to the last, the image resolution does not decrease.

As a result, even in multi-pass recording with a small number of scans, unevenness is less noticeable and an image with a good graininess can be obtained.

In the present application, the liquid to be discharged may have a viscosity and surface tension that can be discharged from the head, and is not particularly limited, but the viscosity becomes 30 mPa · s or less at room temperature, under normal pressure, or by heating or cooling. It is preferable that it is a thing. More specifically, solvents such as water and organic solvents, colorants such as dyes and pigments, polymerizable compounds, resins, functionalizing materials such as surfactants, biocompatible materials such as DNA, amino acids and proteins, and calcium. , Solvents, suspensions, emulsions, etc. containing edible materials such as natural pigments, such as inks for inkjets, surface treatment liquids, components of electronic and light emitting elements, and formation of electronic circuit resist patterns. It can be used in applications such as liquids and material liquids for three-dimensional modeling.

Piezoelectric actuators (laminated piezoelectric elements and thin-film piezoelectric elements), thermal actuators that use electric heat conversion elements such as heat-generating resistors, and electrostatic actuators that consist of a vibrating plate and counter electrodes are used as energy sources for discharging liquid. Includes what to do.

Further, the "device for discharging a liquid" includes not only a device capable of discharging a liquid to a device to which the liquid can adhere, but also a device for discharging the liquid into the air or into the liquid. ..

The "device for discharging the liquid" can also include means for feeding, transporting, and discharging paper to which the liquid can adhere, as well as a pretreatment device, a posttreatment device, and the like.

For example, as a "device that ejects a liquid", an image forming device that is a device that ejects ink to form an image on paper, and a three-dimensional object (three-dimensional object) are formed in layers in order to form a three-dimensional object. There is a three-dimensional modeling device (three-dimensional modeling device) that discharges the modeling liquid into the powder layer.

Further, the "device for discharging a liquid" is not limited to a device in which a significant image such as characters and figures is visualized by the discharged liquid. For example, those that form patterns that have no meaning in themselves and those that form a three-dimensional image are also included.

The above-mentioned "thing to which a liquid can adhere" means a material to which a liquid can adhere at least temporarily, such as a material to which the liquid adheres and adheres, and a material to which the liquid adheres and permeates. Specific examples include paper, recording paper, recording paper, film, recorded media such as cloth, electronic substrates, electronic components such as piezoelectric elements, powder layers (powder layers), organ models, and media such as inspection cells. Yes, and includes everything to which the liquid adheres, unless otherwise specified.

The material of the above-mentioned "material to which a liquid can adhere" may be paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, ceramics or the like as long as the liquid can adhere even temporarily.

Further, the "device for discharging the liquid" includes, but is not limited to, a device in which the liquid discharge head and the device to which the liquid can adhere move relatively. Specific examples include a serial type device that moves the liquid discharge head, a line type device that does not move the liquid discharge head, and the like.

In addition, as a "device for ejecting a liquid", a treatment liquid coating device for ejecting a treatment liquid to the paper in order to apply the treatment liquid to the surface of the paper for the purpose of modifying the surface of the paper, etc. There is an injection granulation device that granulates fine particles of raw materials by injecting a composition liquid in which raw materials are dispersed in a solution through a nozzle.

In addition, in the term of this application, image formation, recording, printing, printing, printing, modeling, etc. are all synonymous.

100 Printing device 105 Carriage 111 Liquid discharge head 400 Image processing device 500 Control unit 515 Image processing unit

Claims (6)

An image processing device that performs halftone processing that expresses gradation by combining dots of multiple sizes.
In the gradation region less than a predetermined value, a pattern is formed by dispersing and arranging the first dots having a resolution and a dot size in which at least a part of the dots does not overlap even if the dot position shift occurs.
In the gradation region of a predetermined value or more, a halftone process is performed in which the second dots having a size that maintains at least a part of the overlap between the dots even if the dot position shift occurs are distributed so as to fill the voids of the pattern. Equipped with means ,
An image processing apparatus characterized in that the liquid constituting the first dot is designated to be composed of a liquid having a concentration lower than that of the liquid constituting the second dot. The first dot forming the pattern contains two or more dots of different sizes.
The image processing apparatus according to claim 1, wherein the pattern is arranged so as to sequentially replace dots having a small size with dots having a large size. The means for performing the halftone processing is
In the gradation region less than a predetermined value, a threshold value is arranged so as to form a pattern by dispersing and arranging the first dots of the dot size and the resolution at which at least a part of the dots does not overlap even if the dot position shift occurs. With a mask,
In the gradation region of a predetermined value or more, the threshold value is arranged so as to fill the voids of the pattern with the second dots having a size that maintains at least a part of the overlap between the dots even if the dot position shift occurs. The image processing apparatus according to claim 1 or 2 , further comprising a threshold mask. A device that discharges a liquid that performs halftone processing that expresses gradation by combining dots of multiple sizes.
In the gradation region less than the predetermined value, even if the dot position shift occurs, at least a part of the dots is dispersedly arranged with the first dots of the resolution and the dot size to form a pattern.
In the gradation region of a predetermined value or more, a halftone process is performed in which the second dots having a size that maintains at least a part of the overlap between the dots even if the dot position shift occurs are distributed so as to fill the voids of the pattern. Equipped with means ,
A device for discharging a liquid, characterized in that the liquid constituting the first dot is designated to be composed of a liquid having a concentration lower than that of the liquid constituting the second dot. It is an image processing method that performs halftone processing that expresses gradation by combining dots of multiple sizes.
In the gradation region less than a predetermined value, a pattern is formed by dispersing and arranging the first dots having a resolution and a dot size in which at least a part of the dots does not overlap even if the dot position shift occurs.
The predetermined value or more tone area, line physician halftone processing dot position shift is distributed so as to fill at least a gap of the pattern in the second dot size some overlap is maintained between even if ,
An image processing method, characterized in that the liquid constituting the first dot is designated to be composed of a liquid having a concentration lower than that of the liquid constituting the second dot. A program that allows a computer to perform halftone processing that expresses gradation by combining dots of multiple sizes.
In the gradation region less than a predetermined value, a pattern is formed by dispersing and arranging the first dots having a resolution and a dot size in which at least a part of the dots does not overlap even if the dot position shift occurs.
The predetermined value or more tone area, and distributed as in the second dot size to at least a portion of the overlap of the dots even when dot position misalignment is maintained fill voids of the pattern,
A program that causes a computer to perform a halftone process that specifies that the liquid constituting the first dot is composed of a liquid having a lower concentration than the liquid constituting the second dot.

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