JP2023133913A - Image processing device and droplet discharge device - Google Patents

Abstract

To improve a smoothing effect of a contour part.SOLUTION: An image processing device includes an acquisition part for acquiring image data, an image processing part for subjecting the image data to image processing, and an output part for outputting the image data subjected to the image processing in the image processing part, wherein the image processing part converts an image shown in the image data into a dot pattern, adds a contour correction dot for contour correction to a contour part of the dot pattern, and executes processing of determining the type of droplets forming the contour correction dot, according to a time difference until the liquid lands on a medium when the contour correction dot and a non-contour correction dot adjacent to the contour correction dot are formed on the medium by discharge of the liquid, or an image formation method of the contour correction dot and the contour correction dot.SELECTED DRAWING: Figure 6

Description

The present invention relates to an image processing device and a droplet ejection device.

Inkjet printers are used in various fields. Such an inkjet printer forms a plurality of dots on a recording medium by ejecting ink droplets (an example of liquid) from a recording head, and forms images such as characters using the dots.

Furthermore, in inkjet printers, contour correction processing is performed to smooth the contours of characters and the like by arranging dots for contour correction (hereinafter also referred to as contour correction dots) on the contours of characters and the like. For example, conventionally, a technique has been disclosed in which dots are arranged around an outline and the brightness of the dots is changed to be higher than the brightness of other dots in the outline (for example, Patent Document 1 reference).

In the smoothing process described above, ink droplets are ejected to form contour correction dots adjacent to dots forming the contour portion (hereinafter referred to as non-contour correction dots). Between adjacent contour correction dots and non-contour correction section dots, the time difference between when an ink droplet is ejected and when it lands on a recording medium (hereinafter also referred to as landing time difference) differs depending on the image forming method. For example, the impact time difference may be different between a method of forming contour-corrected dots and non-contour-corrected dots in one scan and a method of alternately forming contour-corrected dots and non-contour-corrected dots in two scans. become. This difference in landing time is a factor in determining whether coalescence of ink droplets occurs between contour correction dots and dots in non-contour areas.

By the way, if the landing time difference changes due to a change in the image forming method, etc., the formation result of the contour correction dots may not be the intended result, and the smoothing effect may deteriorate. For example, if contour correction dots are formed with a droplet volume that takes into account coalescence of ink droplets in one image forming method, changing the image forming method will change the degree of coalescence of ink droplets, so the dots for contour correction will The appearance of the image may change, and the smoothing effect may decrease.

In addition, in the above-mentioned conventional technology, since no consideration is given to the relationship between the landing time difference and the contour correction dot, the above-mentioned problem cannot be solved.

The present invention has been made in view of the above, and an object of the present invention is to improve the smoothing effect of contour parts.

In order to solve the above problems and achieve the objects, the present invention includes an acquisition section that acquires image data, an image processing section that performs image processing on the image data, and an image processed by the image processing section. an output unit that outputs data, the image processing unit converts the image represented by the image data into a dot pattern, adds contour correction dots for contour correction to the contour portion of the dot pattern, the time difference between the contour correction dots and the non-contour correction dots adjacent to the contour correction dots until the liquid lands on the medium when the liquid is ejected onto the medium, or the contour correction dots and the contour correction Depending on the method of forming an image with the dots, a process of determining the droplet type of the droplet forming the contour correction dot is executed.

According to the present invention, it is possible to improve the smoothing effect of the contour portion.

FIG. 1 is a perspective view showing an example of a liquid ejection device according to an embodiment. FIG. 2 is a diagram illustrating an example of the configuration of the liquid ejection device according to the embodiment. FIG. 3 is a block diagram showing an example of the hardware configuration of the liquid ejection device according to the embodiment. FIG. 4 is a diagram illustrating an example of the configuration of a heater of the liquid ejection device according to the embodiment. FIG. 5 is a block diagram illustrating an example of the hardware configuration of the image processing apparatus according to the embodiment. FIG. 6 is a block diagram showing an example of the functional configuration of the image processing device according to the embodiment. FIG. 7 is a diagram for explaining contour correction processing performed by the image processing unit according to the embodiment. FIG. 8 is a diagram for explaining contour correction processing performed by the image processing unit according to the embodiment. FIG. 9 is a flowchart illustrating an example of processing executed by the image processing apparatus according to the embodiment.

Hereinafter, an image processing device and a droplet ejection device according to embodiments will be described based on the drawings. The configuration of the embodiment described below, and the actions and results (effects) brought about by the configuration are merely examples, and are not limited to the contents described below.

FIG. 1 is a perspective view showing an example of a liquid ejection device 1 according to the present embodiment. FIG. 2 is a diagram showing an example of the configuration of the liquid ejection device 1 according to the present embodiment. The liquid ejection device 1 is, for example, an inkjet printer.

As shown in FIGS. 1 and 2, the liquid ejection device 1 according to the present embodiment includes a device main body 10 and a support base 11 that supports the device main body 10.

The left and right sides of the device main body 10 are provided with side plates 10A and 10B. A guide rod 12 and a guide stay 13, which are guide members, are hung between the side plates 10A and 10B. The liquid ejecting device 1 also includes a sub-sheet metal guide 14 . The guide rod 12 and the guide stay 13 slidably hold the carriage 15.

The main scanning mechanism section 16 that moves and scans the carriage 15 includes a main scanning motor 17 arranged on one side in the main scanning direction, a drive pulley 18 rotationally driven by the main scanning motor 17, and a drive pulley 18 arranged on the other side in the main scanning direction. The driving pulley 19 is provided with a driven pulley 19 disposed in the drive pulley 19 , and a timing belt 20 that is a traction member and is stretched between the drive pulley 18 and the driven pulley 19 . Note that the driven pulley 19 is tensioned outwardly (in the direction away from the drive pulley 18) by a tension spring.

The carriage 15 moves in the direction of arrow A (main scanning direction) via a timing belt 20 that is rotationally driven by a main scanning motor 17 . The carriage 15 is also equipped with an optical sensor 21 that detects the edge of the medium (paper edge).

The carriage 15 includes a liquid ejection head 23 that ejects ink droplets of each color, such as black (K), yellow (Y), magenta (M), and cyan (C), depending on the installed ink cartridge 22. .

The liquid ejection head 23 includes a plurality of nozzles 23a, 23b, and 23c that eject liquid droplets. Note that the liquid ejection head 23 is an example of a liquid ejection section.

The liquid ejection head 23 has a nozzle row consisting of a plurality of nozzles 23a, 23b, and 23c arranged in the direction of arrow B (sub-scanning direction). Here, the sub-scanning direction is a direction orthogonal to the main scanning direction. The liquid ejection head 23 is mounted so that the direction in which ink droplets are ejected from the nozzles 23a, 23b, and 23c is directed downward.

The nozzles 23a, 23b, and 23c of the liquid ejection head 23 are respectively shifted in the sub-scanning direction and grounded. The carriage 15 is equipped with sub-tanks for supplying ink of each color to the liquid ejection heads 23.

The liquid ejection device 1 includes a cartridge loading section 2 into which ink cartridges 22a, 22b, 22c, and 22d of each color are removably installed. The ink in the ink cartridge 22 is replenished and supplied to the sub-tank of the carriage 15 via the supply tubes 24 of each color by a supply pump unit. Note that the ink cartridge 22 may include a white ink cartridge.

The liquid ejecting device 1 includes a maintenance recovery mechanism 3 in a non-printing area on one side of the carriage 15 in the main scanning direction. The maintenance and recovery mechanism 3 maintains or recovers the state of the nozzles 23a, 23b, and 23c of the liquid ejection head 23.

The maintenance and recovery mechanism 3 includes a cap 31 for capping each nozzle surface of the liquid ejection head 23, and a wiping unit 32 for wiping the nozzle surface. Furthermore, a replaceable waste liquid tank is provided on the lower side of the maintenance and recovery mechanism 3 to accommodate waste liquid generated by the maintenance and recovery operation.

Paper 41 is set in the paper feeding means 40, but paper 41 of different sizes in the width direction can also be set.

FIG. 3 is a block diagram showing an example of the hardware configuration of the liquid ejection device 1 according to the present embodiment. As shown in FIG. 3, the liquid ejection device 1 includes a control unit 100, an operation panel 120, a sensor 130, a head driver 140, a main scanning motor 17, a sub-scanning motor 150, a carriage 15, and a conveyor belt. 160, a printer driver 170, a fan 180, and a heater 190.

The control unit 100 includes a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, and a RAM (Random Access Memory) 103.

The CPU 101 controls the entire liquid ejection device 1 . The ROM 102 stores fixed data such as programs executed by the CPU 101. The RAM 103 temporarily stores image data and the like.

The control unit 100 includes an NVRAM (Non Volatile RAM) 104 and an ASIC (Application Specific Integrated Circuit) 105.

The NVRAM 104 is a nonvolatile memory that retains data even when the power to the liquid ejecting device 1 is cut off. The ASIC 105 processes various signal processes for image data, performs image processing such as sorting, and processes other input/output signals for controlling the entire liquid ejecting apparatus 1 .

The control unit 100 includes a print control unit 106. The carriage 15 transfers data for driving the liquid ejection head 23 to the head driver 140. The head driver 140 drives the liquid ejection head 23 provided on the carriage 15 and causes the liquid ejection head 23 to eject ink droplets.

The control section 100 has a motor drive section 107. The motor drive unit 107 drives the main scanning motor 17 and the sub-scanning motor 150. The main scanning motor 17 drives the carriage 15 to move and scan. The sub-scanning motor 150 rotates the conveyor belt 160 by driving.

The control unit 100 has an I/O 108. The I/O 108 acquires information from the sensor 130 and extracts information used for controlling each part of the liquid ejection device 1 main body. For example, the sensor 130 corresponds to a group of sensors such as a photo sensor, a temperature sensor, and an encoder sensor. The operation panel 120 inputs and outputs various information.

The control unit 100 has a host I/F 109. The host I/F 109 transmits and receives data and signals to and from the host side. Specifically, data and signals are transmitted and received from the printer driver 170 side of a host such as an information processing device such as a client PC, an image reading device, and a photographing device via a cable or a network. The CPU 101 reads out and analyzes print data in the reception buffer included in the host I/F 109. Then, the ASIC 105 performs image processing, data sorting, etc., and the image data is transferred from the print control unit 106 to the head driver 140.

The print control unit 106 transfers image data as serial data, and also outputs a transfer clock, latch signal, control signal, etc. necessary for transferring the image data to the head driver 140. The head driver 140 applies drive pulses forming a drive waveform given from the print control unit 106 to the pressure generating means of the liquid ejection head 23 based on image data corresponding to one line of the liquid ejection head 23 that is serially input. selectively given to As a result, the liquid ejection head 23 is driven and liquid is ejected.

Note that by selecting part or all of the pulses that make up the drive waveform and part or all of the waveform elements that form the pulses, it is possible to create dots of different sizes, such as large droplets, medium droplets, and small droplets, for example. It can be separated.

The control unit 100 includes a fan control unit 110 and a heater control unit 111. The fan control unit 110 controls the output of the fan 180 so that air is blown at a predetermined temperature and air volume. The heater control unit 111 controls the heater 190 to reach the set temperature.

The fan 180 is driven to promote convection of air inside the liquid ejection device 1, and prevents the upper part of the liquid ejection device 1 from excessively increasing in temperature due to retention of warmed air. Fan 180 is connected to fan control section 110 of control section 100.

FIG. 4 is a diagram showing an example of the configuration of the heater 190 of the liquid ejection device 1 according to the present embodiment. Note that in the example shown in FIG. 4, for the sake of simplicity, some of the liquid ejection heads 23 are not shown.

As shown in FIG. 4, the heater 190 includes a pre-heater 190a, a print heater 190b, a print heater 190c, a post-heater 190d, and a drying heater 190e. Each of these heaters 190 is provided with a temperature sensor such as a thermistor for temperature control.

The preheater 190a is a device that preheats the medium P to a temperature suitable for forming a liquid application surface. For example, preheater 190a is an aluminum foil cord heater. The preheater 190a is attached to the back surface of the conveyance guide plate 191. The preheater 190a warms the medium P by warming the transport guide plate 191 itself.

The print heater 190b and the print heater 190c are devices that keep the medium P warm when forming a liquid application surface on the medium P. For example, the print heater 190b and the print heater 190c are cord heaters embedded in a platen 192 made of aluminum. The print heater 190b and the print heater 190c warm the medium P by warming the platen 192 itself.

The post heater 190d and the drying heater 190e are devices that warm the medium P on which a liquid coating surface is formed, in order to dry and fix a liquid such as ink. For example, the post heater 190d is an aluminum foil cord heater. The post heater 190d is attached to the back surface of the conveyance guide plate 191. The post heater 190d warms the medium P by warming the transport guide plate 191 itself. Further, for example, the drying heater 190e is an IR heater. The drying heater 190e radiates IR radiation onto the liquid-applied surface of the medium P to dry it. The drying heater 190e may include a fan and be configured to send hot air to the liquid application surface of the medium P.

Next, an example of the operation of the liquid ejection device 1 according to this embodiment will be described.

The CPU 101 reads and analyzes print data in the reception buffer of the host I/F 109, performs necessary image processing, data rearrangement, etc. in the ASIC 105, and transfers the data to the print control unit 106.

The print control unit 106 outputs image data and drive waveforms to the head driver 140 at required timing. Specifically, the print control unit 106 converts and amplifies the drive pulse pattern data stored in the ROM 102 and read out by the CPU 101, thereby generating a drive pulse composed of one drive pulse or a plurality of drive pulses. Generate a waveform.

Note that image data for image output may be generated by storing font data in the ROM 102, for example, or the image data may be developed into a bitmap using a printer driver on the host side and transferred to the liquid ejecting device 1. You may also do so.

The head driver 140 selectively applies drive pulses constituting a drive waveform given from the print control unit 106 to the pressure generating means of the liquid ejection head 23 based on the input image data. The liquid ejection head 23 is driven.

When the heater 190 wakes up from the sleep mode, it lights up and is controlled to a set temperature depending on the medium P and the mode. When the heater 190 is turned on, the liquid ejecting device 1 becomes ready to form a liquid application surface and starts an initial operation for forming the liquid application surface. The drying heater 190e starts lighting when the formation of the liquid application surface starts.

The medium P is set on the preheater 190a side. Further, the medium P is conveyed in the direction of arrow B by a conveyance belt 160 to which a driving force is applied from the sub-scanning motor 150, and a liquid application surface is formed by ejecting liquid from the liquid ejection head 23. For example, as the medium P, in addition to roll-type paper, it is possible to use PET, PVC, OPP, sheet-like media, etc. called flexible packaging media.

The medium P sent from the preheater 190a side is first preheated by the preheater 190a to a temperature suitable for forming a liquid application surface. The preheated medium P is sent by a conveyor belt 160 to an image forming section 193 in which a liquid ejection head 23 is arranged.

In the image forming section 193, the medium P is kept warm by the print heaters 190b and 190c, and a liquid such as ink is ejected therefrom from the liquid ejection head 23 to form a liquid application surface. The warmed air rises together with the steam, but in order to prevent the temperature of the upper part of the liquid discharging device 1 from rising excessively due to its stagnation, the fan 180 promotes air convection.

The medium P is conveyed in the sub-scanning direction, the carriage 15 scans in a direction perpendicular to the moving direction of the medium P, and an image is formed. Note that when forming an image, it is possible to form a high-resolution image by changing the number of scans depending on the resolution of the image to be formed.

The medium P on which the liquid-applied surface has been formed in the image forming section 193 is sent further downstream.

The drying heater 190e preheats the filament to a desired temperature before the medium P on which the liquid application surface is formed arrives. Thereafter, when the medium P on which the liquid application surface is formed arrives, the drying heater 190e is turned on in synchronization with the stop timing of the sub-scanning. The lighting timing can be changed depending on the type of medium P and the mode.

The post heater 190d and the drying heater 190e that sends hot air dry and fix liquid such as ink on the medium P. The medium P that has been dried and fixed is further wound up into a roll downstream.

Next, the image processing device 5 according to this embodiment will be explained. FIG. 5 is a block diagram showing an example of the hardware configuration of the image processing device 5 according to this embodiment.

The liquid ejection device 1 includes an image processing device 5. Note that in this embodiment, the image processing device 5 is connected to the liquid ejection device 1, but the invention is not limited to this. For example, the control unit 100 of the liquid ejection device 1 may have the functions of the image processing device 5.

As shown in FIG. 5, the image processing device 5 includes a CPU (Central Processing Unit) 501, a ROM (Read Only Memory) 502, a RAM (Random Access Memory) 503, a memory 504, and an I/F 505. have

The CPU 501 controls the entire image processing device 5 . The ROM 502 stores fixed data such as programs executed by the CPU 501. The RAM 503 temporarily stores image data and the like.

The memory 504 is configured with a storage device such as a volatile or nonvolatile semiconductor memory, an HDD (Hard Disk Drive), or an SSD (Solid State Drive). Note that the memory 504 may include a ROM 502 and a RAM 503.

The I/F 505 is connected to an external client PC, etc., and transmits and receives data and signals to and from the client PC. The data sent from the client PC etc. also includes image data.

FIG. 6 is a block diagram showing an example of the functional configuration of the image processing device 5 according to this embodiment. As shown in FIG. 6, the image processing device 5 includes an acquisition section 506, an image processing section 507, and an output section 508.

The functions of the image processing unit 507 are realized by the CPU 501 executing a predetermined program. Further, the functions of the acquisition unit 506 and the output unit 508 are realized by the memory 504.

The acquisition unit 506 receives a print job generated by a client PC or the like, and outputs image data and the like in the print job to the image processing unit 507. That is, the acquisition unit 506 acquires image data, print instructions, etc. from the PC.

The image processing unit 507 performs image processing such as halftone processing to convert the image data output from the acquisition unit 506 into a dot pattern. The image processing unit 507 also performs contour correction processing to smooth the contour portion converted into a dot pattern. The image processing unit 507 transmits the processed image data to the liquid ejection device 1 via the output unit 508. Note that details of the contour correction processing performed by the image processing unit 507 will be explained later.

The output unit 508 outputs the image data processed by the image processing unit 507 to the liquid ejection device 1. Note that the output destination is not limited to the liquid ejection device 1. For example, it may be output to a liquid ejecting device other than the liquid ejecting device 1.

Next, the outline correction processing performed by the image processing unit 507 according to this embodiment will be explained. 7 and 8 are diagrams for explaining contour correction processing performed by the image processing unit 507 according to this embodiment.

When an image such as a character shown in FIG. 7(a) is converted into a dot pattern, jaggies occur in its outline as shown in FIG. 7(b). Therefore, as shown in FIG. 7C, the image processing unit 507 executes contour correction processing that adds contour correction dots to the contour portion in order to make the jaggies in the contour portion less noticeable.

In FIG. 7C, hatched dots correspond to contour correction dots added in the contour correction process. Further, dots other than the contour correction dots correspond to non-contour correction dots. Note that the dot size of the contour correction dots is set smaller than the dot size of the non-contour correction dots.

Then, the image processing unit 507 generates image data in which the type of ink droplet forming the contour correction dots is set together with a dot pattern to which the contour correction dots are added, and transmits it to the liquid ejection apparatus 1 . Thereby, the liquid ejecting device 1 prints an image on the medium P based on the image data.

Here, FIG. 7(d) shows the printing result of the dot pattern that has not been subjected to the contour correction process shown in FIG. 7(b). Moreover, FIG. 7(e) shows the printing result of the dot pattern subjected to the contour correction process shown in FIG. 7(c). As is clear from FIG. 7E, the print result after the contour correction process has less jaggies in the contour compared to the print result without the contour correction process.

Incidentally, depending on the image forming method, ink droplets may coalesce between a contour correction dot and a non-contour correction dot adjacent to the contour correction dot. FIG. 7(f) shows a state in which coalescence of ink droplets has occurred. Here, adjacency means adjacency in the main scanning direction, but the concept is not limited to this and may also include adjacency in the sub-scanning direction.

The above-mentioned coalescence of ink droplets occurs more easily as the time difference between the timings at which ink droplets forming adjacent contour-corrected dots and non-contour-corrected dots land on the medium P (hereinafter also referred to as landing time difference) is shorter. Become. For example, in 1-pass, 1/1 interlaced (hereinafter also referred to as 1-scan printing) printing in which printing is performed in the main scanning direction and sub-scanning direction in one scan, adjacent contour correction dots and non-contour correction dots are formed in one scan. Therefore, the difference in landing time becomes short, and coalescence of ink droplets may occur. For example, in 2-pass, 1/2 interlaced (hereinafter also referred to as 2-scan printing) printing in which printing is performed in the main scanning direction and sub-scanning direction in two scans, adjacent contour-corrected dots and non-contour-corrected dots are formed alternately in two parts. In this case, the difference in landing time is longer than in one-scan printing, making it difficult for ink droplets to coalesce.

If coalescence of ink droplets occurs inadvertently, the contour correction dots will form an unintended image, which may lead to deterioration of image quality. Therefore, it is preferable that the diameter of the ink droplets forming the contour correction dots is set to a size that allows the smoothing effect to be maintained even when coalescence occurs. Specifically, the droplet diameter of the contour correction dot is preferably set to a size that can maintain the smoothing effect of the contour portion, taking into account the coalescence of ink droplets that occur during one scan printing. In the following, the dot size of contour correction dots that takes into account the coalescence of ink droplets used during one scan printing is also referred to as "first size."

By the way, as described above, in two-scan printing, the difference in landing time is longer than in one-scan printing, which creates a condition in which it is difficult for ink droplets to coalesce. Therefore, when 2-scan printing is performed using the first size optimized for 1-scan printing, the contour correction dots look different from 1-scan printing, and the smoothing effect of the contour portion may deteriorate.

For example, if coalescence of ink droplets is allowed, the first size will have a size that takes into account droplet movement due to coalescence, but in 2-scan printing, droplet movement due to coalescence does not occur, so The appearance of contour correction dots is different from one-scan printing. In this case, in two-scan printing, the contour correction dots may be printed with greater emphasis than in one-scan printing. In this case, the level difference in the contour part becomes more conspicuous, and the smoothing effect deteriorates.

Therefore, the image processing unit 507 of this embodiment switches the droplet type of the ink droplet forming the contour correction dot according to the landing time difference between the contour correction dot and the non-contour correction dot adjacent to the contour correction dot. Control. In this embodiment, the droplet type of the ink droplets depends on the formation conditions when forming the contour correction dots, such as the droplet volume (ejection amount) of the ink droplets forming the contour correction dots and the dot size of the contour correction dots. handle.

Specifically, the image processing unit 507 derives the landing time difference between the contour correction dot and the non-contour correction dot adjacent to the contour correction dot based on the image forming method, and calculates the difference between the landing time difference and the ink droplet. Compare with the threshold value related to species discrimination. Then, the image processing unit 507 determines the type of ink droplet to be used for forming the contour correction dot based on the comparison result. Here, the threshold value can be set arbitrarily, but in this embodiment, it is assumed that the value of the impact time difference at which coalescence of ink droplets may occur is set.

For example, in the case of one-scan printing, the image processing unit 507 determines that the difference in landing time between adjacent dots is greater than or equal to a threshold value. In this case, the image processing unit 507 sets the dot size of the contour correction dots to the first size. Further, for example, in the case of two-scan printing, the image processing unit 507 determines that the difference in landing time between adjacent dots is less than a threshold value. In this case, the image processing unit 507 sets the dot size of the contour correction dots to a second size smaller than the first size.

FIG. 8 is a diagram showing an example of a processing result of the image processing unit 507. FIG. 8 shows a state in which the dot size (first size) of the contour correction dots shown in FIG. 7(e) has been changed to a second size. As described above, in two-scan printing, it is difficult for ink droplets to coalesce, so by reducing the dot size, it is possible to prevent contour correction dots from being emphasized. This makes it possible to improve the smoothing effect of contour parts in two-scan printing.

Note that the image processing unit 507 determines the droplet type of the ink droplets that form the contour correction photo according to the image forming method of the liquid ejection device 1 to which the image data is output, but this is not limited to this. It's not a thing. For example, the droplet type may be determined according to the image forming method designated by the user.

Further, in the above example, the image processing unit 507 derives the landing time difference based on the image forming method, but the method of deriving the landing time difference is not particularly limited. For example, the image processing unit 507 may calculate the landing time difference between the contour correction dots and the non-contour correction dots based on a relational expression for calculating the landing time difference predetermined for each image forming method. Furthermore, for example, the image processing unit 507 may use a landing time difference explicitly instructed via the I/F 505 or the like as the derivation result. Furthermore, since the image forming method and the landing time difference uniquely correspond to each other, the image processing unit 507 is configured to omit the derivation of the landing time difference and determine the droplet type of the ink droplet that forms the contour correction dot according to the image forming method. You can also use it as

Next, with reference to FIG. 9, the processing executed by the image processing device 5 will be described. FIG. 9 is a flowchart illustrating an example of processing executed by the image processing device 5.

First, the acquisition unit 506 acquires image data generated by a PC application or the like via a cable or a network (step S11).

Subsequently, the image processing unit 507 converts the image data acquired by the acquisition unit 506 into a dot pattern (step S12). Next, the image processing unit 507 performs contour correction processing to add contour correction dots to the contour portion of the image data converted into a dot pattern (step S13).

Next, the image processing unit 507 specifies the impact time difference between the contour correction dot and the non-contour correction dot adjacent to the contour correction dot based on the image forming method of the image data (step S14). Next, the image processing unit 507 compares the specified landing time difference with a threshold value and determines whether there is a possibility that coalescence of ink droplets will occur (step S15).

If the impact time difference exceeds the threshold, the image processing unit 507 determines that coalescence of ink droplets may occur (step S15; Yes). In this case, the image processing unit 507 sets the droplet type of the contour correction dot to the first size (step S16), and proceeds to step S18.

On the other hand, if the landing time difference is less than or equal to the threshold, the image processing unit 507 determines that coalescence of ink droplets does not occur (step S15; No). In this case, the image processing unit 507 sets the droplet type of the contour correction dot to a second size smaller than the first size (step S17), and proceeds to step S18.

Then, the output unit 508 outputs the output image data processed in step S16 or step S17 to the liquid ejection apparatus 1 (step S18).

As described above, in the contour correction process, the image processing device 5 according to the present embodiment determines whether ink droplets forming a contour correction dot are Change species. As a result, the image processing device 5 can add contour correction dots with a dot size that corresponds to the printing direction to the contour portion, so even if the image forming method is changed, the smoothing effect of the contour portion can be improved. can be achieved.

Note that the embodiments described above can be modified and implemented as appropriate by changing part of the configuration or function of each of the devices described above. Therefore, some modified examples of the above-described embodiment will be described below as other embodiments. Note that, below, points that are different from the embodiments described above will be mainly explained, and detailed explanations of points that are common to those already explained will be omitted. Further, the modified examples described below may be implemented individually or in appropriate combinations.

(Modification 1)
In the above-described embodiment, one-scan printing and two-scan printing are illustrated as image forming methods, but the image forming method to which droplet types of contour correction dots are switched is not limited to these.

For example, in the liquid ejection apparatus 1 in which the carriage 15 forms an image by ejecting ink droplets while reciprocating in the width direction (main scanning direction) of the medium P, unidirectional printing and bidirectional printing can be performed. Unidirectional printing is a method in which an image is formed by ejecting ink only when the carriage 15 moves forward (or backward). Bidirectional printing is a method in which the carriage 15 operates to form an image by discharging ink on both forward and backward passes.

In the case of unidirectional printing, ink is ejected only on the outward pass, and empty scanning is performed on the return pass. In this case, for example, one of the contour correction dots and non-contour correction dots is formed in the forward scan, and the other dot is formed in the next forward scan. In addition, in the case of bidirectional printing, ink is ejected on the outward pass and the return pass, so for example, one of the contour correction dots and non-contour correction dots is formed on the outward pass, and the other dot is formed on the return pass. things are done.

Comparing the above-mentioned unidirectional printing and bidirectional printing, since image formation can be performed faster in bidirectional printing, the difference in landing time in bidirectional printing is shorter than that in unidirectional printing. becomes.

Therefore, the image processing unit 507 according to this modification sets the droplet type of contour correction dots to the first size when the image forming method is bidirectional printing, and sets the droplet type of contour correction dots to the first size when the image forming method is unidirectional printing. The droplet type is determined to be the second size.

Thereby, the image processing device 5 according to the present modification can achieve the same effect as the embodiment described above, and thus can improve the smoothing effect of the contour portion.

Note that even in the case of bidirectional printing, the difference in impact time may become long depending on the position where the image is formed. Specifically, the difference in impact time becomes longer as the distance from the switching point from the forward route to the return route increases. Here, the switching point is the end of the medium P that is the switching position from the forward path to the return path within the movable range of the carriage 15 in the main scanning direction, or the point on the guide rod 12 and the guide stay 13 from the forward path to the return path. corresponds to the switching position.

In this case, the image processing unit 507 determines the droplet type of the ink droplet forming the contour correction dot according to the distance from the switching point. For example, the image processing unit 507 sets the droplet type of contour correction dots included in a range of distance from the switching point where ink droplets may coalesce from the switching point to the first size, and sets the droplet type to the first size, and The droplet type of the contour correction dots outside the range is determined to be the second size.

As a result, the image processing device 5 according to this modification can switch the droplet type of the ink droplet to the location where the contour correction dot is formed even in the case of bidirectional printing, so that the smoothing effect can be more effectively achieved. can be improved.

(Modification 2)
In the above-described embodiment, a configuration has been described in which the type of droplet of the contour correction dot is determined based on the landing time difference or the image forming method. However, the degree of coalescence of ink droplets also depends on the characteristics (or type) of the medium P. Specifically, since the time for ink droplets to settle differs depending on the type of medium P, the time for ink droplets to coalesce differs. Therefore, in this modification, a configuration will be described in which the droplet type of the contour correction dot is determined by taking into consideration the characteristics of the medium P.

The image processing unit 507 according to this modification determines the type of medium P used in the liquid ejection device 1. Here, the method for determining the type of the medium P is not particularly limited; for example, the image processing unit 507 determines the type of the medium P by acquiring information that can specify the type of the medium P from the liquid ejection device 1. You may. Further, the image processing unit 507 may determine the type of medium P based on information indicating the type of medium P input by the user.

Next, the image processing unit 507 adjusts the method for determining the droplet type of the contour correction dot according to the type of the medium P. For example, the image processing unit 507 corrects the landing time difference depending on the type of the medium P, or corrects a threshold value related to determining the type of ink droplet. Further, for example, the image processing unit 507 corrects the droplet amount and dot size of the droplet type determined by the image forming method according to the type of medium P. For example, if the type of medium P is a film type that is difficult for ink to penetrate than plain paper, the image processing unit 507 adjusts the threshold value to reduce the impact time difference that may cause ink droplets to coalesce. Expanding.

As a result, the image processing device 5 according to this modification can switch the droplet type of the ink droplet to the location where the contour correction dot is formed according to the type of the medium P, and therefore improve the smoothing effect more effectively. can be done.

Note that the programs executed by each device of the above-described embodiments and modifications are provided in a state that is pre-installed in a ROM, a storage unit, or the like. The programs executed on the devices of the embodiments and modifications described above are files in an installable or executable format and can be stored on a CD-ROM, a flexible disk (FD), a CD-R, a DVD (Digital Versatile Disk), etc. It may also be configured to be recorded on a computer-readable recording medium and provided.

Furthermore, the programs executed by the devices of the embodiments and modifications described above may be stored on a computer connected to a network such as the Internet, and may be provided by being downloaded via the network. Furthermore, the programs executed by each device of the above-described embodiments and modified examples may be provided or distributed via a network such as the Internet.

Although the embodiments and modifications of the present invention have been described above, these embodiments and modifications are presented as examples, and are not intended to limit the scope of the invention. These novel embodiments and modifications can be implemented in various other forms, and various omissions, substitutions, changes, and combinations can be made without departing from the gist of the invention. These embodiments and modifications are included within the scope and gist of the invention, as well as within the scope of the invention described in the claims and its equivalents.

1 Liquid discharge device 5 Image processing device 10 Device main body 506 Acquisition section 507 Image processing section 508 Output section

Japanese Patent Application Publication No. 2008-73853

Claims (9)

an acquisition unit that acquires image data;
an image processing unit that performs image processing on the image data;
an output unit that outputs the image data subjected to image processing by the image processing unit;
Equipped with
The image processing unit converts the image represented by the image data into a dot pattern,
Adding contour correction dots for contour correction to the contour portion of the dot pattern,
the time difference until the liquid lands on the medium when the contour correction dot and the non-contour correction dot adjacent to the contour correction dot are formed on the medium by ejecting liquid, or the contour correction dot and the contour correction executing a process of determining a droplet type of a droplet forming the contour correction dot according to an image forming method with the dot;
Image processing device. The image processing unit determines, as a droplet type of the droplet, a droplet amount of a droplet forming the contour correction dot or a dot size of the contour correction dot.
The image processing device according to claim 1. The image processing unit determines a droplet type of a first size smaller than the dot size of the non-contour correction dot when the time difference is less than or equal to a threshold, and determines a droplet type of a second size smaller than the first size when the time difference exceeds the threshold. Determine the size of the droplet type,
The image processing device according to claim 1 or 2. When the image forming method is a method of forming the contour correction dots and the non-contour correction dots in one scan, the image processing unit is configured to generate droplets of a first size smaller than the dot size of the non-contour correction dots. If the image forming method is a method of alternately forming the contour correction dots and the non-contour correction dots in two scans, determining a droplet type of a second size smaller than the first size. do,
The image processing device according to claim 1 or 2. When the image forming method is a method in which an ejection head that scans the medium in the width direction ejects the droplets in both forward and backward passes, the image processing unit In the case of a method in which a droplet type of a first size smaller than the dot size is determined and the droplet is ejected on either the forward path or the backward path to form an image, a droplet type of a second size smaller than the first size is determined. determine,
The image processing device according to claim 1 or 2. When the image forming method is a method in which an ejection head that scans the medium in the width direction ejects the droplets in both the outward path and the backward path, the image processing unit determining the droplet type of the droplet forming the contour correction dot according to the distance from the switching point;
The image processing device according to claim 1 or 2. The image processing unit determines a droplet type of a droplet forming the contour correction dot, taking into account the type of the medium.
The image processing device according to any one of claims 1 to 6. The image processing unit determines a liquid type of a droplet forming the contour correction dot according to an image forming method of a liquid ejection device to which the image data is output.
The image processing device according to any one of claims 1 to 7. An image processing device according to any one of claims 1 to 8,
a liquid ejection unit that ejects droplets based on image data processed by the image processing device;
A liquid ejection device comprising:

Images