JP2023159620A - Image processing device, recording device, image processing method, and program - Google Patents

Abstract

To restrict deterioration in data transfer efficiency of mask processing performed while switching mask patterns according to a gradation level of recording data.SOLUTION: In an image processing device, first setting means 301 sets an initial gradation level of each of a plurality of unit regions, on the basis of recording data corresponding to each of the unit regions defined on a recording medium. Second setting means 305 sets a common gradation level in each unit region in an expansion area corresponding to N unit regions on the basis of the initial gradation level set for each of the N unit regions that are continuous in a sub-scanning direction. Mask acquisition means 307 acquires a mask pattern corresponding to each of N (N: an integer of 2 or more) unit regions in accordance with the gradation level shared by the N unit regions. Generation means 308 creates dot data corresponding to a unit region on the basis of the mask pattern acquired by the mask acquisition means 307 and recording data of the unit region.SELECTED DRAWING: Figure 3

Description

The present invention relates to a technique for performing image processing for recording dots on a recording medium while moving a recording means capable of recording dots in the main scanning direction.

2. Description of the Related Art In inkjet printing apparatuses, a so-called multi-pass method is known as a printing method for realizing high-quality image printing, in which printing is performed by scanning a print head multiple times over the same area of a print medium. In the multi-pass method, print data to be printed on the same area is divided into a plurality of parts, and the same area is scanned multiple times based on the divided print data. At this time, a mask pattern that determines whether dot recording is permitted or not is used to divide the print data. The mask pattern needs to be synchronized with the main scan of the print head and the conveyance of the print medium (movement in the sub-scan direction).

Patent Document 1 discloses a technology that allows a small-sized mask pattern corresponding to a unit area of an image, which is a unit of data transfer, to be retrieved from a mask pattern table, and creates a mask pattern of a size corresponding to the size of the image data area. It has been known. According to this, even if the feed amount is temporarily changed during printing, it is possible to synchronize the mask pattern with the main scanning of the printing head and the conveyance of the printing medium.

In addition, Patent Document 2 discloses that, in order to further improve image quality (improving graininess and gloss), multiple types of mask patterns (gradation mask ) has been disclosed.

Japanese Patent Application Publication No. 2003-320648 Japanese Patent Application Publication No. 2010-120291

Even when using a gradation mask as in Patent Document 2, it is necessary to synchronize the main scanning, sub-scanning, and mask pattern with each other, as in the case where a normal mask pattern is used. Therefore, a technique using a small-sized mask pattern corresponding to a unit area of an image, as disclosed in Patent Document 1, is effective. However, when using small-sized mask patterns by switching them for each gradation level, the switching cycle of the mask patterns may become short. That is, small-sized mask patterns may be frequently switched in response to changes in image gradation. In this case, continuous data transfer is hindered by the mask pattern switching process, resulting in a decrease in data transfer efficiency. The reduction in data transfer efficiency affects the moving speed of the print head in the main scanning direction, and becomes a factor that reduces the throughput of the printing apparatus.

The present disclosure aims to provide a technique that can suppress a decrease in data transfer efficiency in mask processing performed while switching mask patterns depending on the gradation level of recording data.

The present disclosure relates to a recording scan in which dots are recorded on a recording medium while moving a recording means in which a plurality of recording elements are arranged in a main scanning direction, and a recording medium intermittently in a sub-scanning direction that intersects the main scanning direction. an image processing apparatus that performs image processing for recording an image of the same area of the recording medium by a plurality of recording scans, the image processing apparatus comprising: a first setting means for setting an initial gradation level of each of the unit areas based on recording data corresponding to each of the unit areas; and N (N: an integer of 2 or more) consecutive units in the sub-scanning direction. a second setting means for setting a common gradation level for the N unit areas in the expansion area based on the initial gradation level set for each unit area in the expansion area corresponding to the area; mask holding means for holding mask patterns corresponding to each of a plurality of gradation levels for dividing the recording data into a plurality of dot data indicating dot recording or non-recording corresponding to each of a plurality of recording scans; , a mask acquisition means for acquiring from the mask holding means a mask pattern corresponding to each of the N unit areas according to a gradation level common to the N unit areas; a mask pattern acquired by the mask acquisition means; generation means for generating a plurality of dot data corresponding to the unit area based on the recording data of the unit area;
It is characterized by having the following.

According to the present disclosure, it is possible to perform mask processing while switching mask patterns depending on the gradation level of print data while suppressing a decrease in data transfer efficiency.

FIG. 1 is an external perspective view showing a schematic configuration of an inkjet recording apparatus. FIG. 2 is a block diagram showing a control configuration of an inkjet recording apparatus. FIG. 2 is a block diagram showing a circuit configuration of a recording data processing section and its peripheral configuration. FIG. 2 is a schematic explanatory diagram of multi-pass printing. It is a flowchart which shows the processing procedure performed in 1st Embodiment. It is a diagram showing an example of arrangement of mask data in a storage area. It is an explanatory diagram showing processing performed in S102. It is an explanatory diagram showing processing performed in S105. It is a flowchart which shows the processing procedure performed in 2nd Embodiment. FIG. 2 is an explanatory diagram showing a method for acquiring gradation levels.

Embodiments according to the present disclosure will be described below. Note that the following embodiments do not limit the present disclosure according to the claims, and not all combinations of features disclosed in the present embodiments are essential to the solution means of the present disclosure.

(First embodiment)
In this embodiment, an inkjet printing apparatus (hereinafter referred to as a printing apparatus) that performs printing by ejecting ink from the ejection openings of a printing head, and an image processing apparatus provided in the printing apparatus will be taken as an example and explained. Further, the printing apparatus in this embodiment performs a printing scan in which ink is ejected from the print head while moving the print head in a direction intersecting the arrangement direction of the ejection ports (main scan), and also moves the print medium in the arrangement direction of the ejection ports. This is a serial type recording device that conveys data intermittently along the direction.

Hereinafter, a recording apparatus according to this embodiment and an image processing apparatus used in the recording apparatus will be described with reference to the drawings.

The printing apparatus of this embodiment applies at least one nozzle group out of a plurality of nozzle groups set in the printing head to the same area on the printing medium multiple times. It uses a multi-pass method that completes the image by scanning.

FIG. 1 is an external perspective view showing a schematic configuration of a recording apparatus 1 in this embodiment. The recording apparatus 1 is provided with a carriage 2 that can reciprocate along the x direction (main scanning direction). The carriage 2 is equipped with a recording head 3 serving as a recording means for recording dots on a recording medium P by ejecting ink, and an ink cartridge 6 containing ink to be supplied to the recording head 3. The ink cartridge 6 is removably mounted on the carriage 2. In the recording apparatus 1 of this embodiment, four ink cartridges each containing magenta (M), cyan (C), yellow (Y), and black (K) inks are installed in the carriage 2 to enable color recording. It is installed. These four ink cartridges are independently removable.

In the recording head 3, ejection ports capable of ejecting ink are arranged along a direction intersecting the x direction (in this example, the y direction perpendicular to the x direction). Further, within the recording head 3, an ejection energy generating element that generates ejection energy for ejecting ink is provided at a position facing each of the plurality of ejection ports. The recording head 3 of this embodiment employs an ejection method that ejects ink using thermal energy. For this reason, an electrothermal converter is used as the ejection energy generating element. The electrothermal converter heats the ink by applying a pulse voltage based on the ejection data, and ejects the ink from the ejection port. Note that the ejection opening and the energy generating element (electrothermal converter) that ejects ink from the ejection opening constitute a recording element that records dots on the recording medium P. That is, the recording head 3 has a plurality of recording elements arranged along the x direction, and these plurality of recording elements constitute a recording element array.

Further, an encoder scale 7 is provided on the main body of the recording apparatus 1 along the main scanning direction (x direction), and slits are provided in the encoder scale 7 at regular intervals. When the carriage 2 moves in the main scanning direction, an encoder sensor (not shown) provided on the carriage 2 reads the slit of the encoder scale 7 and generates a pulsed encoder signal. The count value of this encoder signal becomes a value representing the position of the carriage 2 in the main scanning direction (that is, the position of the recording head). Therefore, the encoder signal is used as a signal for controlling the timing of ejecting ink from the ejection ports of the print head 3. Further, the moving speed of the carriage is calculated based on the cycle of the encoder signal (encoder signal interval).

The feeding mechanism 5 feeds the recording medium P into the recording apparatus main body one by one from among the plurality of recording media P stacked on the feeding tray 5a. The conveying means 8 conveys the recording medium P fed by the feeding mechanism 5 to a recording position by the recording head 3 along the conveying direction. In this embodiment, the conveyance means 8 has a conveyance direction that is the y direction, which is the direction in which the discharge ports are arranged. Here, the recording head 3 moves in the main scanning direction together with the carriage 2 and discharges ink based on the dot data. As a result, the ink ejected from the ejection ports lands on an area having a predetermined width (distance in the direction perpendicular to the x direction) on the recording medium P, and dots are recorded. Thereafter, the conveying means 8 conveys the recording medium P by a predetermined distance in the y direction. As described above, the printing apparatus 1 according to the present embodiment performs printing scanning in which dots are printed by ejecting ink from the ejection ports while moving the printing head 3 in the main scanning direction, and the transporting operation of the printing medium P by the transporting means. By repeating this process, an image for one sheet is formed on the recording medium. Note that in the following description, the conveyance direction (y direction) of the recording medium P is also referred to as the sub-scanning direction.

Further, the printing apparatus 1 in this embodiment employs a multi-pass method in which the printing head 3 performs printing scans on the same area on the printing medium P a plurality of times to complete an image. The multipath method will be explained later using FIG. 4.

FIG. 2 is a block diagram showing the control configuration of the recording apparatus 1 in this embodiment. The recording device 1 is connected to a host device 900 via a host interface 111. Image data transmitted from the host device 900 is stored in a reception buffer 116A provided in the RAM 116 via the host interface.

The image processing unit 114 converts the image data into multi-value or binary print data for each print element array, and stores the converted print data in a print data buffer 116B provided in the RAM 116. The image processing unit 114 also calculates and obtains the amount of ink applied (amount applied) for each predetermined area (unit area) on the recording medium P based on the print data, and sets the obtained amount of ink to the gradation level. It is stored in the gradation level buffer 116D as a gradation level buffer 116D.

The record data processing unit 115 converts the record data into binary data if it is multi-value data. Furthermore, the recording data processing unit 115 selects a mask pattern corresponding to the gradation level stored in the gradation level buffer 116D from among the mask patterns stored in the mask data buffer 116E. Then, mask processing is performed on the binary print data using the selected mask pattern to generate binary data (dot data) that controls dot printing or non-printing by the print head 3, and stores it in the dot data buffer 116C. do. Further, the printhead control unit 121 transfers the dot data stored in the dot data buffer 116C to the printhead 3.

The processing of the recording data processing section 115 described above is performed in synchronization with the heat trigger signal output from the encoder processing section 112. Further, the processing of the recording head control section 121 is performed in synchronization with the block trigger signal outputted by the encoder processing section 112. Therefore, the processing of the print data processing section 115 and the processing of the print head control section 121 are performed in synchronization with the transport timing. The CPU 117 performs drive control of the recording elements, control of the conveyance operation of the recording medium P by the conveyance means 8, etc. according to a control program stored in the ROM 118.

FIG. 3 is a block diagram showing the circuit configuration of the recording data processing unit 115 that constitutes the image processing device (image processing means) in this embodiment, and the peripheral configuration of the recording data processing unit 115. The encoder information output circuit 200 is provided within the encoder processing section 112 (FIG. 2). The encoder information output circuit 200 outputs signals (heat trigger signal, block trigger signal, etc.) for controlling the operation timing of each circuit provided in the recording data processing section 115 and the recording head control section 121.

The gradation level calculation circuit (first setting means) 301 calculates the amount of ink applied for each unit area set on the recording medium P based on the recording data. In this embodiment, the unit area has a length corresponding to a predetermined number of recording elements arranged in the sub-scanning direction (in this example, a length of eight recording elements (eight pixels)), and a length corresponding to a predetermined number of recording elements arranged in the sub-scanning direction. This is an area (an 8×8 pixel area) having a length of 16 pixels in the scanning direction (x direction). The implantation amount calculated by the gradation level calculation circuit 301 is stored in the gradation level buffer 116D as a gradation level.

The recording data processing unit 115 also includes a recording data acquisition circuit 302, a data conversion circuit 303, a gradation level acquisition circuit 304, a gradation level recalculation circuit 305, a mask data selection circuit 306, a mask data acquisition circuit 307, and a mask processing circuit. It includes a circuit (generating means) 308 and the like. The recording data acquisition circuit 302 is a circuit that acquires recording data, and the data conversion circuit 303 is a circuit that outputs binary recording data. If the recording data input from the recording data acquisition circuit 302 is multi-valued data, it is converted into binary recording data and output. Furthermore, when the data output from the recording data acquisition circuit 302 is binary data, the data conversion circuit 303 outputs the binary data.

The gradation level acquisition circuit (second setting means) 304 is a circuit that acquires data from the gradation level buffer 116D for each unit area. In addition, the gradation level recalculation circuit 305 expands the length of the unit area in the sub-scanning direction by N times (N is an integer of 2 or more), that is, N unit areas that are continuous in the sub-scanning direction. The gradation level is recalculated for each corresponding area). Hereinafter, the extended area will also be referred to as a recalculation area. The recalculated gradation level becomes a gradation level common to a plurality of unit areas located within the expanded area. Note that the value of N for setting the expansion area is set by the CPU 117. Further, the gradation level recalculation by the gradation level recalculation circuit 305 is performed every main scan (hereinafter also referred to as pass) of the print head 3.

Based on the gradation level set by the gradation level recalculation circuit 305, the mask data selection circuit 306 selects one type of mask data from among the plurality of types of mask data provided corresponding to each of the plurality of gradation levels. This is a mask data selection circuit that selects mask data. The mask data acquisition circuit (mask acquisition means) 307 acquires the mask data of the mask pattern selected by the mask data selection circuit 306 from the mask data buffer (mask data holding means) 116E.

The mask processing circuit 308 performs mask processing on the binary print data output from the data conversion circuit 303 using the mask data acquired by the mask data acquisition circuit 307, and determines whether or not dots are recorded in the target main scan. Generate dot data representing the record. The dot data generated here is stored in the dot data buffer 116C.

FIG. 4 is a schematic explanatory diagram of the multipath method. Here, the image for the same area on the print medium P is completed by performing four print scans with the print head 3 while intervening a predetermined amount of conveyance operation between each print scan. A four-pass multipath method will be explained as an example. In order to simplify the explanation, in the recording element array 300, 16 recording elements 300a that eject the same type of ink are arranged in a line along the conveyance direction (y direction) of the recording medium P. shall be taken as a thing.

When performing four-pass multi-pass printing, the printing element array 300 is divided into first to fourth printing element groups (first printing element group G1 to fourth printing element group G4). In the illustrated example, since the printing element array 300 is made up of 16 printing elements 55, each printing element group is made up of four printing elements. The area on the recording medium where four dots are formed by the recording scan by one recording element group, that is, the area where 4 dots x 4 dots (=16 dots) are formed, is considered to be the same area on the recording medium. .

Furthermore, first to fourth mask patterns are associated with the first to fourth recording element groups G1 to G4, respectively. Each mask pattern is a pattern that performs mask processing to divide print data representing an image to be formed in the same area into dot data corresponding to each of a plurality of (in this case, four) print scans.

In each mask pattern, areas shown in black indicate permissible areas where recording of dots is permitted, and areas shown in white represent non-permissible areas where recording of dots is not permitted. The first to fourth mask patterns have a mutually complementary relationship. That is, by overlapping the first to fourth mask patterns, all areas in the same area become permissible areas. In order to simplify the explanation of the multipath method, an example is shown in which the same area is 4 areas x 4 areas, but in reality the same area has a larger area in both the x and y directions. are doing. The processing procedure when executing four-pass printing in the printing data processing unit and its peripheral configuration in this embodiment will be explained with reference to the flowchart in FIG. 5. Note that in the following explanation, an area where 16 dots are formed in the main scanning direction (x direction) by 8 recording elements in the sub scanning direction (y direction), that is, 8×16 pixels (=124 pixels) The area will be explained as a unit area. Therefore, it is assumed that the mask pattern corresponding to the unit area has an 8×16 area.

First, the image processing unit 114 stores the processed recording data in the recording data buffer 116B (S100). Next, based on the print data, the amount of ink ejected for each unit area (area of 8 x 16 pixels) is calculated, and the value corresponding to the calculated amount of ink ejected is stored as a gradation level in the gradation level buffer 116D. (S101). Note that a specific method for setting the gradation level will be described later.

Further, the CPU 117 generates mask data (8×16 areas) corresponding to each unit area for each gradation level, and stores it in the mask data buffer 116E (S102). Then, before the processing of the print data processing unit 115 for each pass is started, the CPU 117 sets an area setting value N for determining the area to be subjected to the gradation level recalculation process performed in S106 ( S103). The area subject to the recalculation process has a length obtained by extending the reference length in the sub-scanning direction based on the length of the unit area (8 x 16 pixels) in the sub-scanning direction, The value indicating the expansion magnification is the area setting value N. This area setting value N is an integer of 2 or more.

Next, based on the output signal from the encoder information output circuit 200, the recording data acquisition circuit 302 acquires from the recording data buffer 116B the amount of recording data necessary for the processing of the recording head control unit 121 (S104), and converts the data. It is sent to circuit 303. If the recording data sent from the recording data acquisition circuit 302 is multi-value data, the data conversion circuit 303 converts the multi-value data into binary data (S105).

Next, based on the output signal from the encoder information output circuit 200, the gradation level acquisition circuit 304 acquires the gradation level for the recording element row (S106), and converts the acquired gradation level to the gradation level recalculation circuit. 305. In the gradation level recalculation circuit 305, an expanded area whose size in the sub-scanning direction is expanded based on the area setting value N set in S103 based on the gradation level calculated for each unit area (8 x 16 pixels). (Recalculation area) A common gradation level is recalculated (S107). The expanded area is an area whose size in the main scanning direction is N times the unit area (N is an integer of 2 or more). That is, the expanded area has a size of 8×N pixels in the sub-scanning direction and a size of 16 pixels in the main-scanning direction.

The mask data selection circuit 306 selects a mask pattern corresponding to the recalculated gradation level, and outputs information representing the selected mask pattern to the mask data acquisition circuit 307. The mask data acquisition circuit 307 acquires mask data represented by the input information from the mask data buffer 116E (S108). The acquired mask data is sent to the mask processing circuit 308.

The mask processing circuit 308 processes the binary recording data acquired by the recording data acquisition circuit 302 or the binary recording data converted by the data conversion circuit 303 using the mask data acquired by the mask data acquisition circuit 307. Perform mask processing. That is, a logical AND operation is performed between the print data and the mask data to generate dot data indicating whether dots are printed or not printed by each print element of the print head 3 in each print scan. The generated dot data is stored in the dot data buffer 116C.

Thereafter, the recording head control unit 121 reads dot data from the dot data buffer 116C at a predetermined timing based on the output signal from the encoder processing unit, drives each recording element of the recording head 3 based on the dot data, and Dots for scanning are recorded. After the recording operation for one scan, the conveying means 8 conveys the recording medium by a predetermined distance. This recording scan by the recording head 3 and the conveyance operation of the recording medium are repeated four times. This completes recording of the image in each unit area within the area having a width of 8 dots in the sub-scanning direction. Thereafter, by repeating the recording scan and the conveyance operation of the recording medium, recording of the image on one recording medium is completed.

FIG. 6 is a diagram showing an example of the arrangement of mask data corresponding to each of a plurality of gradation levels in the mask data buffer 116E. Here, mask data corresponding to one gradation level is arranged in an area corresponding to a row of recording elements. In the figure, Base Address indicates the address of mask data for gradation level 0, and Base Address+offset Address indicates the address of mask data for gradation level 1, respectively. Similarly, Base Address*offset Address indicates the address of mask data for gradation level 2, and Base Address+3*offset Address indicates the address of mask data for gradation level 3, respectively.

By adopting such a mask data arrangement form, it is possible to obtain mask data corresponding to each gradation level of each unit area corresponding to eight recording elements. However, in order to acquire mask data of different gradation levels, it is necessary to switch the acquisition address for acquiring mask data. For this reason, when the gradation level of a unit area changes frequently, it is necessary to switch the mask data acquisition address frequently, which reduces the number of bursts when acquiring mask data and increases the system Data transfer efficiency decreases. As a result, the moving speed of the print head 3 in the main scanning direction is restricted, which becomes a factor that reduces the throughput of the printing apparatus.

Therefore, in this embodiment, the gradation level recalculation circuit 305 sets an extended area (8N x 16 pixels) in which the size of the unit area in the sub-scanning direction is expanded by N times, and a gradation level common to the expanded area is set. Recalculate the level. That is, the gradation level of each unit area existing in the extended area corresponding to 8×N recording elements is made to match. This makes it possible to reduce the number of times the mask data acquisition address is switched, to enable burst transfer in which mask data is read out continuously, and to improve data transfer efficiency.

FIG. 7 is a diagram schematically showing the gradation level setting process executed when performing the gradation level storage process in S101 of FIG. In the figure, 310 and 320 indicate print data recorded in each of two unit areas adjacent in the sub-scanning direction. When setting the gradation level of print data corresponding to each unit area (8 x 16 pixels), first calculate the amount of ink applied to the unit area based on each print data corresponding to each unit area. . In this embodiment, the number of recording data (0 to 128) for which dot recording is determined is calculated out of the total number of pixels (128 pixels = 8×16 pixels) included in a unit area. Then, it is determined to which of the implantation amount classifications determined for each gradation level the calculated implantation amount falls. For example, when the total implantation amount within a unit area falls into the category 0 to 31, the gradation level of the unit area is set to "0". In addition, if the total amount of implantation in a unit area is 32 to 63, the gradation level is set to "1", if it falls under the category 64 to 95, the gradation level is set to "2", If it falls under the category, the gradation level is set to "3". In this way, a gradation level is set for the recording data corresponding to each unit area, and each gradation level is stored in the gradation level buffer 116D.

FIG. 8 is a diagram schematically showing the gradation level recalculation process executed in S107 of FIG. When the area setting value N is set to 2, an extended area is set in which the length of the unit area in the sub-scanning direction is doubled. Then, based on the gradation levels set for each of the two unit areas located within the expanded area, a recalculation process is performed to newly calculate the gradation level common to each of the two unit areas. FIG. 8 shows two unit areas 321 and 322 adjacent in the sub-scanning direction, and each unit area corresponds to eight recording elements arranged in the sub-scanning direction. The gradation levels shown in the unit areas 321 and 322 on the left side of FIG. 8 indicate the initial gradation levels set before the recalculation process is performed. That is, it shows the gradation level set in S101 of FIG. 5. On the other hand, the gradation levels shown in the unit areas 321 and 321 on the right side of FIG. 8 indicate the gradation levels of each unit area 321 and 322 calculated by the recalculation process. As shown in the figure, the gradation level of each unit area 321 and 322 after the recalculation process is the same (gradation level 3 in the figure).

The recalculation process is performed based on the initial gradation level set for each of the two unit areas 321 and 322 shown on the left side of FIG. In this embodiment, the process of calculating the average value of the initial gradation level of the unit area 321 and the initial gradation level of the unit area 322 is performed as a recalculation process, and the obtained gradation level is used as the gradation level common to each area. level. In the example shown in FIG. 8, the initial gradation level of the unit area 322 is "3", and the initial gradation level of the unit area 322 is "2". Therefore, the average value of the unit areas 321 and 322 is (2+3)/2=2.5, and by rounding up the decimal point, the common gradation level in each unit area 321 and 322 is "3". . That is, the gradation level of the expanded area is set to "3". In this manner, in this embodiment, by taking the average value of the initial gradation levels of the two unit areas 321 and 322, a common gradation level that reflects the initial gradation levels of each unit area 321 and 322 is obtained. It is possible to set the level. Therefore, it is possible to maintain the effectiveness of using the gradation mask, ie, the effectiveness of reducing graininess in low density areas and improving gloss in high density areas.

As described above, according to this embodiment, a unit area, which is the smallest unit of mask processing, is set, and a gradation level common to an extended area obtained by multiplying the unit area by an integer in the sub-scanning direction is applied to each unit area. Set based on the initial tone level that is set. Thereby, it is possible to reduce mask pattern switching processing while maintaining the synchronization of mask patterns in each pass and the effectiveness of using mask patterns according to gradation levels. Therefore, even if the gradation level of recorded data changes continuously in short cycles, it is possible to reduce the number of mask pattern switching processes and improve the data transfer efficiency on the system. can.

Furthermore, in this embodiment, as shown in S103 in FIG. 2, since the area setting value N is set for each path, it is possible to appropriately set the expansion area corresponding to that path. Therefore, even if the feed amount is temporarily changed due to a change in the physical condition of the recording medium or mechanical factors during printing, the mask pattern will change in the main scanning direction, sub-scanning direction, and mask pattern. It becomes possible to maintain synchrony with

In this embodiment, the processes of S104 to S108 are performed sequentially, but the process of preparing binary recording data of S104 to S105 and the process of preparing mask data of S106 to 108 are performed in parallel. I don't mind going there.

Furthermore, in this embodiment, the initial gradation level is calculated for each unit area of 8 pixels in the sub-scanning direction x 16 pixels in the main scanning direction, but the unit area can also be set to other sizes. It is possible.

Furthermore, in the present embodiment, an example has been shown in which the gradation level in each unit area is determined based on which of the predetermined categories the ink ejection amount calculated for each gradation level corresponds to. However, the setting of the gradation level is not limited to this. It is also possible to set the gradation level of each unit area using a table that defines gradation levels according to the amount of ink applied.

Further, in this embodiment, an example is shown in which recording is performed using a four-pass multi-pass method, but the present disclosure is also applicable to recording using a multi-pass method with a number of passes other than four passes. Furthermore, the recording apparatus described in the above embodiments can form dots using multiple types of recording materials such as ink. Therefore, the above-mentioned processing is performed for each type of ink.

(Second embodiment)
Next, a second embodiment of the present disclosure will be described. Like the first embodiment, this embodiment similarly includes the configurations shown in FIGS. 1 to 3. Therefore, detailed explanation regarding the same configuration and processing as in the first embodiment will be omitted. Hereinafter, differences between this embodiment and the first embodiment will be mainly described.

FIG. 9 is a flowchart showing the processing procedure executed by the recording data processing section and its peripheral components in the second embodiment. Note that in FIG. 9, the same process numbers are given to processes that perform the same processes as those shown in FIG.

In this embodiment, the processes of S100 to S102 in FIG. 9 are performed in the same manner as in the first embodiment. That is, the gradation level is obtained and stored for each unit area (8×16 pixels), and mask data of a mask pattern corresponding to the stored gradation level is stored in the mask data buffer 116E.

Thereafter, in this embodiment, the conveyance amount M of the recording medium is acquired in S203. The conveyance amount M refers to the conveyance amount for one time of the recording medium P that is intermittently conveyed. In this embodiment, the minimum transport amount is the transport amount corresponding to an area of 8 recording elements (an area of 8 pixels) in the sub-scanning direction, and the transport amount is an integral multiple of the minimum transport amount (an integral multiple of 8 pixels). It is set as M. This is because gradation level calculations and mask data calculations are performed for each unit area (8 pixels x 16 pixels) corresponding to 8 printing elements, so the mask pattern for each pass of multi-pass printing is This is because in order to achieve synchronization, it is necessary to set the minimum conveyance amount to eight recording elements. Therefore, if the size of the area (unit area) that is the target of gradation level calculation or mask data calculation changes, the value of the transport amount M also changes.

After obtaining the transport amount M, the same processing as in the first embodiment is performed in S104 to S106. Next, in S207, based on the initial gradation level calculated for each unit area (8 x 16 pixels) according to the transport amount M obtained in S203, 8 x m (m is a divisor of M) records The gradation level common to the extended area (recalculation area) corresponding to the element is recalculated. After that, in S108 to S110, dot data is generated by the same processing as in the first embodiment.

FIG. 10 is a diagram illustrating a gradation level acquisition method when the recalculation area corresponding to 8×m (m: a divisor of M) printing elements is an area with a transport amount of M or more. In FIG. 10, the transport amount M corresponds to a distance of 16 recording elements (16 pixels), and the length of the gradation level recalculation area in the sub-scanning direction corresponds to 8×m=32 recording elements (32 pixels). An example is shown.

If the length of the recalculation area in the sub-scanning direction is longer than the conveyance distance as in this example, if the initial gradation level is obtained from the beginning of the printing element row in each pass, the recalculation result for the same area will be The first pass and the second and subsequent passes may not match. This will be explained in detail below.

In the first pass (first printing scan), the acquisition start address for obtaining the gradation level for the printing element row is set to 0x00, and in the second pass (second printing scan), the gradation level for the printing element row is set to 0x00. Assume that the acquisition start address when acquiring the key level is set to 0x04. Here, the acquisition start address 0x00 corresponds to the beginning of the recording element array in the first pass, and the acquisition address 0x04 corresponds to the beginning of the recording element array in the second pass. When the acquisition start address of each pass is set in this way, in the first pass, the gradation level of the recalculation area is recalculated based on the gradation level of the area 0x00 to 0x06. Furthermore, in the second pass, the gradation level of the recalculation area is recalculated based on the gradation level of the area from 0x04 to 0x0A. In this case, the gradation levels after 0x04 may not be the same between the first pass and the second pass.

Therefore, in this embodiment, the gradation level of the recalculation area is acquired for each pass by taking into consideration the relationship between the conveyance amount of the print medium and the size of the recalculation area in the sub-scanning direction. Adjust the gradation level acquisition start position so that the gradation levels are aligned. That is, if the size of the recalculation area in the sub-scanning direction is larger than the transport distance of the print medium, the same recalculation area as in the first pass is set and the gradation level is recalculated. Specifically, the gradation level acquisition start address in the second pass is set to 0x00, as in the first pass. That is, in the second pass, the gradation level of the second pass is recalculated using the common gradation level set during the printing scan of the first pass for the area overlapping with the first pass. This makes it possible to set the same recalculation area in the first and second passes, and there will be no mismatch between the mask patterns set in the same extended area in either pass. , the tunability of the mask pattern in each pass can be maintained.

Furthermore, control may be performed to change the conveyance amount during a printing operation on one printing medium. For example, the conveyance amount M may be changed depending on whether printing is performed on the leading or trailing edge portion of the recording medium P or when printing is performed on the center portion of the recording medium P. In this case as well, the transport amount M is changed for each pass by obtaining the transport amount M for each pass and setting a recalculation area (an area for 8×m recording elements) according to the transport amount M. Even if this is the case, it is possible to maintain synchronization between the main scanning direction, the sub-scanning direction, and the mask pattern.

As described above, according to this embodiment, the data transfer efficiency on the system is improved while maintaining the synchronization of the mask pattern in each pass, taking into account the relationship between the conveyance amount of the recording medium and the recalculation area. can be done.

(Other embodiments)
It is possible to perform a combination of the processes shown in the first embodiment and the second embodiment described above. For example, it is also possible to determine the area for recalculating the gradation level by taking into account both the area setting value N and the transport amount M described in the first embodiment.

In the above embodiment, a multi-pass method is used as an example in which an image is recorded by scanning the same area on a recording medium multiple times with different nozzle groups among a plurality of nozzle groups set in a recording head. Although described above, the present disclosure is not limited thereto. The present disclosure sets the amount of conveyance of the print medium once to a distance corresponding to the print element row of the print head, and scans the print head multiple times without changing the relative position between the nozzle row of the print head and the print medium. This method is also effective in a recording method (divided recording method) in which recording is performed using multiple recording methods.

Further, the disclosure of this embodiment includes the following configuration and method.

(Configuration 1)
A recording scan in which dots are recorded on a recording medium while moving a recording means in which a plurality of recording elements are arranged in a main scanning direction, and a recording medium intermittently conveyed in a sub-scanning direction that intersects with the main scanning direction. An image processing apparatus that performs image processing for recording an image of the same area of the recording medium by a plurality of recording scans, the image processing apparatus comprising:
a first setting means for setting an initial gradation level of each of the unit areas based on recording data corresponding to each of the plurality of unit areas defined on the recording medium;
The N in the expansion area is determined based on the initial gradation level set for each unit area in the expansion area corresponding to N (N: an integer of 2 or more) unit areas that are continuous in the sub-scanning direction. a second setting means for setting a common gradation level of the unit areas;
mask holding means for holding mask patterns corresponding to each of a plurality of gradation levels for dividing the recording data into a plurality of dot data indicating dot recording or non-recording corresponding to each of a plurality of recording scans; ,
a mask obtaining means for obtaining a mask pattern corresponding to each of the N unit areas from the mask holding means according to a gradation level common to the N unit areas;
generation means for generating the plurality of dot data corresponding to the unit area based on the mask pattern acquired by the mask acquisition means and the recording data of the unit area;
An image processing device comprising:

(Configuration 2)
The second setting means is characterized in that the average value of the initial gradation levels set in each of the N unit areas continuous in the sub-scanning direction is set as the common gradation level. , the image processing device according to Configuration 1.

(Configuration 3)
The setting of the common gradation level by the second setting means, the acquisition of the mask pattern by the mask acquisition means, and the generation of the dot data by the generation means are performed for each recording scan. , the image processing device according to configuration 1 or 2.

(Configuration 4)
The mask acquisition means continuously acquires mask patterns corresponding to the N unit areas from the mask holding means according to the common gradation level set by the second setting means. The image processing device according to any one of configurations 1 to 3.

(Configuration 5)
5. The image processing apparatus according to any one of configurations 1 to 4, wherein the unit area is an area corresponding to a predetermined number of the recording elements arranged in the sub-scanning direction.

(Configuration 6)
The N continuous unit areas in the sub-scanning direction are an integer number of areas of 2 or more set based on the conveyance amount of the recording medium by one conveyance operation of the conveyance operation that is performed intermittently. 6. The image processing device according to any one of configurations 1 to 5, characterized in that:

(Configuration 7)
The recording means has a recording element array made up of a plurality of recording elements arranged in the sub-scanning direction,
The recording element array is composed of a plurality of recording element groups divided by the number of recording scans performed on the same area,
7. The image processing apparatus according to configuration 6, wherein the conveyance amount is set to a distance corresponding to the number of recording elements included in the recording element group.

(Configuration 8)
The conveyance amount corresponds to a length that is an integral multiple of the length of the unit area in the sub-scanning direction,
Image processing according to configuration 7, wherein the length of the expansion area in the sub-scanning direction is an integral multiple of the length of the unit area in the sub-scanning direction, and is longer than the transport amount. Device.

(Configuration 9)
The second setting means sets the gradation level of each unit area in the second and subsequent recording scans performed on the same area to the common gradation level set in the first recording scan performed on the same area. The image processing device according to configuration 8, wherein the image processing device is set to .

(Configuration 10)
10. The image processing apparatus according to any one of configurations 1 to 9, wherein the generating means generates the dot data by performing an AND operation between binary recording data and the mask pattern.

(Configuration 11)
11. The image processing apparatus according to any one of configurations 1 to 10, wherein each of the means is provided for each color type of dots to be recorded.

(Configuration 12)
The recording element is an ejection energy generating element that ejects ink,
12. The image processing apparatus according to any one of configurations 1 to 11, wherein dots are recorded on a recording medium by ink ejected by the recording element.

(Configuration 13)
A recording scan in which dots are recorded on a recording medium while moving a recording head in which a plurality of recording elements are arranged in a main scanning direction, and a recording scan in which the recording medium is intermittently conveyed in a sub-scanning direction that intersects with the main scanning direction. A recording apparatus comprising an image processing means that performs image processing for recording an image of the same area of the recording medium by a plurality of recording scans, the recording apparatus comprising:
The image processing means includes:
a first setting means for setting an initial gradation level of each of the unit areas based on recording data corresponding to each of the plurality of unit areas defined on the recording medium;
of the N unit areas based on the initial gradation level set for each unit area in the extended area corresponding to N (N: an integer of 2 or more) unit areas continuous in the sub-scanning direction. a second setting means for setting a common gradation level;
a mask holding means for holding a mask pattern corresponding to each of a plurality of gradation levels for dividing the print data into a plurality of dot data indicating recording or non-recording of a dot, corresponding to each of a plurality of recording scans; ,
a mask obtaining means for obtaining a mask pattern corresponding to each of the N unit areas from the mask holding means according to a gradation level common to the N unit areas;
generation means for generating the plurality of dot data corresponding to the unit area based on the mask pattern acquired by the mask acquisition means and the recording data of the unit area;
A recording device comprising:

(Method 1)
A recording scan in which dots are recorded on a recording medium while moving a recording head in which a plurality of recording elements are arranged in a main scanning direction, and a recording scan in which the recording medium is intermittently conveyed in a sub-scanning direction that intersects with the main scanning direction. An image processing method that performs image processing for recording an image of the same area of the recording medium by a plurality of recording scans, the method comprising:
setting an initial gradation level for each of the unit areas based on recording data corresponding to each of the plurality of unit areas defined on the recording medium;
of the N unit areas based on the initial gradation level set for each unit area in the extended area corresponding to N (N: an integer of 2 or more) unit areas continuous in the sub-scanning direction. a step of setting a common gradation level;
From a mask holding means that holds mask patterns for dividing the print data into dot data corresponding to each of a plurality of print scans corresponding to each of a plurality of gradation levels, a gradation common to the N unit areas is stored. obtaining a mask pattern corresponding to each of the N unit areas according to the tone level;
generating a plurality of dot data corresponding to the unit area based on the obtained mask pattern and the recording data of the unit area;
An image processing method comprising:

(Program 1)
A program for causing a computer to execute each step in the image processing method described in Method 1.

1 Recording device 3 Recording head 116E Mask data buffer 300a Recording element 301 Gradation level calculation circuit 305 Gradation level recalculation means 307 Mask acquisition circuit 308 Mask processing circuit P Recording medium

Claims (15)

A recording scan in which dots are recorded on a recording medium while moving a recording means in which a plurality of recording elements are arranged in a main scanning direction, and a recording medium intermittently conveyed in a sub-scanning direction that intersects with the main scanning direction. An image processing apparatus that performs image processing for recording an image of the same area of the recording medium by a plurality of recording scans, the image processing apparatus comprising:
a first setting means for setting an initial gradation level of each of the unit areas based on recording data corresponding to each of the plurality of unit areas defined on the recording medium;
The N in the expansion area is determined based on the initial gradation level set for each unit area in the expansion area corresponding to N (N: an integer of 2 or more) unit areas that are continuous in the sub-scanning direction. a second setting means for setting a common gradation level of the unit areas;
mask holding means for holding mask patterns corresponding to each of a plurality of gradation levels for dividing the recording data into a plurality of dot data indicating dot recording or non-recording corresponding to each of a plurality of recording scans; ,
a mask obtaining means for obtaining a mask pattern corresponding to each of the N unit areas from the mask holding means according to a gradation level common to the N unit areas;
generation means for generating the plurality of dot data corresponding to the unit area based on the mask pattern acquired by the mask acquisition means and the recording data of the unit area;
An image processing device comprising: The second setting means is characterized in that the average value of the initial gradation levels set in each of the N unit areas continuous in the sub-scanning direction is set as the common gradation level. , The image processing device according to claim 1. The setting of the common gradation level by the second setting means, the acquisition of the mask pattern by the mask acquisition means, and the generation of the dot data by the generation means are performed for each recording scan. , The image processing device according to claim 1 or 2. The mask acquisition means continuously acquires mask patterns corresponding to the N unit areas from the mask holding means according to the common gradation level set by the second setting means. The image processing device according to claim 1. The image processing apparatus according to claim 1, wherein the unit area is an area corresponding to a predetermined number of the recording elements arranged in the sub-scanning direction. The N continuous unit areas in the sub-scanning direction are an integer number of areas of 2 or more set based on the conveyance amount of the recording medium by one conveyance operation of the conveyance operation that is performed intermittently. The image processing device according to claim 1, characterized in that: The recording means has a recording element array made up of a plurality of recording elements arranged in the sub-scanning direction,
The recording element array is composed of a plurality of recording element groups divided by the number of recording scans performed on the same area,
7. The image processing apparatus according to claim 6, wherein the conveyance amount is set to a distance corresponding to the number of recording elements included in the recording element group. The conveyance amount corresponds to a length that is an integral multiple of the length of the unit area in the sub-scanning direction,
The image according to claim 7, wherein the length of the expansion area in the sub-scanning direction is an integral multiple of the length of the unit area in the sub-scanning direction, and is longer than the transport amount. Processing equipment. The second setting means sets the gradation level of each unit area in the second and subsequent recording scans performed on the same area to the common gradation level set in the first recording scan performed on the same area. The image processing apparatus according to claim 8, wherein the image processing apparatus is set to . 2. The image processing apparatus according to claim 1, wherein the generating means generates the dot data by performing an AND operation between binary recording data and the mask pattern. 2. The image processing apparatus according to claim 1, wherein each of said means is provided for each color type of dots to be recorded. The recording element is an ejection energy generating element that ejects ink,
The image processing apparatus according to claim 1, wherein dots are recorded on a recording medium by ink ejected by the recording element. A recording scan in which dots are recorded on a recording medium while moving a recording head in which a plurality of recording elements are arranged in a main scanning direction, and a recording scan in which the recording medium is intermittently conveyed in a sub-scanning direction that intersects with the main scanning direction. A recording apparatus comprising an image processing means that performs image processing for recording an image of the same area of the recording medium by a plurality of recording scans, the recording apparatus comprising:
The image processing means includes:
a first setting means for setting an initial gradation level of each of the unit areas based on recording data corresponding to each of the plurality of unit areas defined on the recording medium;
of the N unit areas based on the initial gradation level set for each unit area in the extended area corresponding to N (N: an integer of 2 or more) unit areas continuous in the sub-scanning direction. a second setting means for setting a common gradation level;
a mask holding means for holding a mask pattern corresponding to each of a plurality of gradation levels for dividing the print data into a plurality of dot data indicating recording or non-recording of a dot, corresponding to each of a plurality of recording scans; ,
a mask obtaining means for obtaining a mask pattern corresponding to each of the N unit areas from the mask holding means according to a gradation level common to the N unit areas;
generation means for generating the plurality of dot data corresponding to the unit area based on the mask pattern acquired by the mask acquisition means and the recording data of the unit area;
A recording device comprising: A recording scan in which dots are recorded on a recording medium while moving a recording head in which a plurality of recording elements are arranged in a main scanning direction, and a recording scan in which the recording medium is intermittently conveyed in a sub-scanning direction that intersects with the main scanning direction. An image processing method that performs image processing for recording an image of the same area of the recording medium by a plurality of recording scans, the method comprising:
setting an initial gradation level for each of the unit areas based on recording data corresponding to each of the plurality of unit areas defined on the recording medium;
of the N unit areas based on the initial gradation level set for each unit area in the extended area corresponding to N (N: an integer of 2 or more) unit areas continuous in the sub-scanning direction. a step of setting a common gradation level;
From a mask holding means that holds mask patterns for dividing the print data into dot data corresponding to each of a plurality of print scans corresponding to each of a plurality of gradation levels, a gradation common to the N unit areas is stored. obtaining a mask pattern corresponding to each of the N unit areas according to the tone level;
generating a plurality of dot data corresponding to the unit area based on the obtained mask pattern and the recording data of the unit area;
An image processing method comprising: A program for causing a computer to execute each step in the image processing method according to claim 14.

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