JP2024006190A - Recording device and method for recording - Google Patents

Abstract

To solve such the problem that, when determining a unique mask pattern from the total dot number for recording in a recording region, it is impossible to perform synchronization with control that operates with a unit smaller than a recording region unit, such as a code table for conveyance amount control and binarization.SOLUTION: A recording device switches a mask in accordance with ink density for each of the predetermined areas of a recording region, thereby providing high-quality recording while synchronizing with control that operates with a unit smaller than a recording region unit.SELECTED DRAWING: Figure 4

Description

The present invention relates to a recording device and a recording method for recording an image on a recording medium.

2. Description of the Related Art An inkjet recording device is known as a recording device that records an image while scanning a carriage. An inkjet recording apparatus records an image by ejecting ink onto a recording medium using a recording head equipped with an energy generating element (recording element) such as a heater or a piezo element. In addition, the recording head is moved and scanned in the main scanning direction, and the recording scan in which ink is ejected as droplets onto an area on the recording medium is repeated, and the recording medium is conveyed in the sub-scanning direction that intersects with the main scanning direction. The image is recorded on the recording medium.

In such an inkjet recording apparatus, when a glossy recording medium such as glossy paper is used, high-quality image formation is required in consideration of glossiness and graininess.

Patent Document 1 discloses a method for achieving both graininess and gloss by selecting a dispersion mask in low-duty areas of a recorded image and a concentrated mask in high-duty areas based on the amount of ink applied. There is.

Japanese Patent Application Publication No. 2010-120291

However, in the method of Patent Document 1, the mask pattern is uniquely determined from the total number of dots recorded in the recording area, so the code table for conveyance amount control and binarization is used in units smaller than the recording area unit. cannot be synchronized with the control that operates on it.

In view of this problem, it is an object of the present invention to realize high-quality recording while synchronizing control that operates in units smaller than recording area units.

The present invention is a recording apparatus that records an image by scanning a recording means, which is provided with a recording element row for each ink color, in which a plurality of recording elements are arranged for ejecting ink, multiple times, the recording means scanning. a conveying means for conveying a recording medium in a direction intersecting with the direction; a counting means for counting dots of input image data for each area; and an encoding means for encoding the dot count value by the counting means in accordance with a threshold value. a comparison means for comparing adjacent dot count values, a correction means for correcting a code value when the value encoded by the encoding means in the comparison means exceeds a set value, and the correction means storage means for storing the encoded value, selection means for selecting mask data corresponding to each code value, and means for switching the mask data according to the value read from the storage means; The apparatus is characterized by comprising a generation means for generating recording data using the mask data selected by the selection means.

According to the present invention, it is possible to select an optimal mask pattern according to the duty of the image and record a high-quality image while synchronizing with control that operates in units smaller than recording area units.

A perspective view showing a schematic configuration of a recording section Explanatory diagram of the recording head Temperature characteristics of the recording head temperature detection diode Explanatory diagram of density level encoding means Flowchart of intensity level encoding means Diagram showing how to apply mask data Diagram showing the arrangement of mask data

(First embodiment)
Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing a schematic configuration of a printing section of an inkjet printing apparatus according to this embodiment. In FIG. 1, an inkjet recording apparatus 100 includes an automatic feeding section 101, a conveyance section 103, and a recovery section 108. The automatic feeding unit 101 automatically feeds a recording medium such as paper into the main body of the apparatus. The conveyance unit 103 guides the recording medium fed out one by one from the automatic feeding unit 101 to a predetermined recording position, and also guides the recording medium from the recording position to the ejection unit 102. The recovery unit 108 performs recovery processing on the recording unit that performs desired recording on the recording medium that has been conveyed to the recording position. The recording unit includes a carriage 105 supported movably in the main scanning direction of arrow X by a carriage shaft 104, and a recording head 201 detachably mounted on the carriage 105.

The carriage 105 is provided with a carriage cover 106 that engages with the carriage 105 and guides the recording head 201 to a predetermined mounting position on the carriage 105, and a head set lever 107. The head set lever 107 engages with the tank holder of the recording head 201 and presses the recording head 201 to set it in a predetermined mounting position. A head set plate (not shown) is provided on the upper part of the carriage 105 so as to be rotatable about a head set lever shaft, and is provided at a portion that engages with the recording head 201 and is biased by a spring. Due to the spring force, the head set lever 107 is configured to be attached to the carriage 105 while pressing the recording head 201.

FIG. 2 is an explanatory diagram of the recording head 201. The recording head 201 engages with the carriage 105 to perform recording. Ink stored in the ink cartridge 202 is supplied to the recording head 201. The ink cartridge 202 individually stores ink such as black (Bk), cyan (C), magenta (M), and yellow (Y), and each storage chamber is integrally configured. The print head 201 includes a print element array for each ink color.

The print head 201 includes a print element row 203 in row A in the figure. The X direction in the figure is the "main scanning direction", and the Y direction intersecting the X direction is the "sub scanning direction". Each recording element row 203 includes a plurality of recording elements 204. The recording elements 204 are electrothermal transducers, are arranged along the Y direction, and eject ink from ejection ports (nozzles) in which the recording elements 204 are provided. This embodiment employs an inkjet recording method in which a heater is used as a recording element and ink is ejected using thermal energy. A recording element array 203 provided in the recording head 201 is used for recording one color component. The print head 201 prints an image on a print medium by ejecting ink during multiple scans in the X direction.

Here, the ASIC 301 and SD-RAM 302 used in the inkjet recording apparatus 100 will be explained. FIG. 3 shows the configuration of the ASIC 301 and the SD-RAM 302 in detail, and shows the units related to these.

The PC 303 exists outside the recording device, and transfers recording data to the recording device, more precisely, to the data receiving section of the ASIC 301. While processing image data, the ASIC 301 drives the CR motor 304 and the transport motor 305 to record an image. A CR motor 304 is a motor for moving the carriage 105 in the main scanning direction. The operation of the CR motor 304 is controlled by a CR motor control unit 306, and the position of the carriage 105 in the main scanning direction can be obtained from an encoder signal from an encoder 307 mounted on the carriage 105. When printing is performed in the main scanning direction, the transport motor 305 transports the printing medium in the sub-scanning direction, and printing in the main scanning direction is repeated. The movement in the sub-operation direction is controlled by the transport motor control section 308.

Next, the inside of the ASIC 301 will be explained. Regarding the main blocks, the CPU 309 supervises and manages the overall operation of the ASIC, and the main memory of the recording apparatus system of this embodiment is the SD-RAM 302. Incidentally, this does not necessarily have to be SD-RAM, and may be D-RAM, S-RAM, or any memory other than SD-RAM as long as it falls within the definition of RAM. The CPU 309 performs drive control of printing elements, relative conveyance control between the printing elements and paper, etc., which will be described later, in accordance with a control program stored in the ROM 310. SD-RAM 302 and ROM 310 are connected to the internal bus of ASIC 301 through memory controller 311 and memory controller 312.

Next, the random logic part will be explained. The reception I/F 313 is an interface unit that receives data transferred from the PC 303. For example, this receiving I/F 313 takes in signals in accordance with an interface protocol such as USB or IEEE1394, and generates data in a format that is easy to handle by the ASIC. Normally, it is preferable to generate data in units of 1 byte. The generated data is stored in the SD-RAM 302. The area within the SD-RAM 302 that stores data received via the reception I/F 313 is called a reception buffer 302a. The data stored in the reception buffer 302a is command-analyzed by the CPU 309, and then expanded for each color in the input image buffer 302b using the reception data expansion block 314. At this time, data is developed, the number of data is counted for each predetermined area, and the dot count value is stored in the dot count buffer 302c.

The density encoding block 315 performs encoding according to the density level according to the dot count data stored in the dot count buffer 302c and the threshold table. During encoding, the density values of adjacent areas are compared, and if the density changes, the density level is adjusted and stored in the density buffer 302d.

The image data stored in the input image buffer 302b is divided into a plurality of areas, and is read out by the mask control block 316 at a predetermined timing of recording control. At this time, the mask control block 316 simultaneously reads the density level stored in the density buffer 302d, switches the read address of the mask buffer according to the read density level, and reads the mask pattern from the mask buffer 302e. In this way, an optimal mask pattern is selected according to the density level. The mask control block 316 masks data from a mask pattern corresponding to the print data stored in the input image buffer 302b and stores it in the high speed memory 317. A data storage high-speed memory 317 in which image data for each recording element row is stored is read by a drive data conversion block 318, and a head drive block 320 converts the data into a format that can be efficiently read. Save in memory 319. High speed memory 317 and high speed memory 319 are not essential to the system. Data may be held in a low-speed memory using a wide bus, or an external storage device outside the ASIC may be used as long as sufficient time can be taken to read the data. The high speed memory 319 for storing recorded image data is read out by the head drive block 320. Then, according to the drive order set in the block drive table 321, device control specific to the print head, such as transferring print image data to the print head 201 and transmitting a heat pulse signal, is performed. Further, the generated timing signal generation unit 322 is a block that generates various recording timings from the encoder. A signal is generated at appropriate intervals based on the encoder signal of the encoder 307, and is supplied to the head drive block 320 so that data can be generated in real time at an appropriate timing.

Next, a method of converting data into density data according to this embodiment will be described using FIG. 4. FIG. 4 shows a dot count 401 that is the number of dots counted within an 8 dot x 8 dot area when printing data of 48 dots in the main scanning direction and 32 dots in the sub scanning direction. The print data is binary data, and the number of 1 data indicating the ejection of the print data is counted. For example, if there is 1 data indicating three prints in an 8 dot x 8 dot area, the dot count number is 3. Become. In this example, binary data was used to count the number of 1's in the recorded data within an 8 dot x 8 dot area, but the recorded data may also count the number of 0's in the recorded data, and the recorded data may be multivalued. It doesn't matter if it's data. When handling multi-value data, for example, when processing data with 4-bit multi-value data, the dot count is set according to the data value, such as 0x1 is counted as 1 dot, 0x2 is counted as 2 dots, etc. Convert and add the dot count. At this time, the number of dots to be converted does not need to be correlated with the size of the data value. The number of dots can be freely set such that 0x1 is 7 dots and 0x4 is 2 dots. Further, the area does not necessarily have to be 8 dots x 8 dots, and may be set in units that are easy to process.

The dot count value stored in the dot count buffer 302c is read out by the density encoding block 315 and converted into density data. The density encoding block 315 generates density data using the read dot count 401 and threshold table 402. The threshold table is a table for converting the density into a code value according to the number of dot counts. If the count number in the 8 dot x 8 dot area is 0 to 16, it is Level 0, if it is 17 to 32, it is Level 1, if it is 33 to 48, it is Level 2, if it is 49 to 64, it is Level 3, etc. The dot count value is used as density data. Convert to In this embodiment, the encoding from the dot count value to the density level is expressed in four gradations from Level 0 to Level 3, but there is no limit to the Levels that can be handled, and it can be subdivided into Levels that require density discrimination. Can be done.

Here, if the dot counts differ greatly between adjacent areas of 8 dots x 8 dots, a difference in adjacent density will occur even after conversion to density data. Since control is performed by switching mask data for each density data, when there is a difference between adjacent density levels, the mask data used also changes significantly from the highest duty mask data to the lowest duty mask data. . Therefore, in this embodiment, data is compared between adjacent density data, and if there is a level difference between adjacent areas that is greater than a set value, the density data 403 whose level value has been corrected is used. generate. Here, if the levels of vertically and horizontally adjacent density data differ by three or more levels, the level values of the density data are corrected so as to bring them closer to the center. In FIG. 4, the levels are corrected for both the higher and lower levels, but it is also possible to lower only the higher level by one level or raise only the lower level by one level. Furthermore, correction may be made not only for vertical and horizontal adjacencies but also for diagonal adjacencies, and the level difference upon correction does not need to be 3. Furthermore, in the adjacent region 404a in FIG. 4, since Level0 and Level3 are adjacent to each other, Level0 is corrected to Level1, and Level3 is corrected to Level2. In the adjacent region 404b, Level 0 is adjacent to the Level 3 data in two places, to the right and below, but the correction is performed by lowering the level by one level. If a plurality of level differences occur in adjacent areas as described above, it is also possible to adjust the levels of the adjacent areas where the level differences occur. In these correction means, parameters can be set so that correction can be made according to a set value as an operation mode. The generated density data 403 is stored in the density buffer 302d of the SD-RAM 302. You can switch whether or not to use density data for each ink color individually, and you can switch between colored and transparent inks, warm and cool inks, or process only one specific color. For the remaining ink colors, normal masks may be used. Further, regarding the dot count, only one ink color may be encoded, or, for example, the sum of two dot count values, cyan and magenta, may be encoded. Thereby, density level correction can be performed across a plurality of colors.

Next, a density level correction flowchart of this embodiment will be described using FIG. 5. In S501, each parameter is set. For example, in the density encoding block 315, the setting of a threshold table, how far apart the levels of adjacent areas should be before correction is performed, and when a level difference occurs, correction is performed to lower the higher level; If this occurs, the setting is such that correction is made to raise the lower level. In S502, the dot count value stored in the dot count buffer 302c is read. In S503, the read dot count value is converted into density data according to the table parameters of the threshold table. In S504, adjacent density data are compared, and if a level difference greater than a set value occurs between adjacent data, the density data is corrected. In S505, the corrected density data is stored in the density buffer 302d.

Next, a method of applying a density level mask according to this embodiment will be described using FIG. 6. FIG. 6A shows mask data 401 stored in the mask buffer 302e when the density data is not used, and how the mask data 401 is applied to the image of the paper data. . As shown in FIG. 6A, the mask data 401 is arranged continuously in the printing element column direction (sub-scanning direction). The mask control block 316 continuously reads mask data (1) in the direction of the recording element columns, and when the reading of data for the recording element columns is completed, offsets the address by AddressOffset and starts reading mask data (2). conduct. This is repeated for the data area in the main scanning direction.

Here, application of mask data when using the density data of this embodiment will be explained. When using density data, prepare mask data according to the density. At this time, Level1 mask data is placed at a location offset by LevelOffset from Level0 mask data (Lvl0 mask data) in FIG. 6(b) placed on the base. Furthermore, Level 2 mask data is placed from a position offset by LevelOffset. Thereafter, masks for each density data are placed at addresses offset by Level×LevelOffset with respect to the Level 0 mask data. Thereby, predetermined mask data can be read by simply adding an address obtained by multiplying the read density data by LevelOffset.

(Second embodiment)
In the first embodiment described above, the mask control block 316 reads the density level as well as the image data, and selects a mask buffer according to the read density level. In this embodiment, as shown in FIG. 7, density information added mask data 501 to which density level information is added in advance is prepared in the mask buffer 302e. The density information added mask data 501 can be generated at the same time as density data is generated in the density encoding block 315. Further, the density information added mask data 501 may be generated using a dedicated processing block (not shown) before the mask control block 316 operates.

A mask pattern is generated by adding density level information to the mask buffer 302e, and the mask control block 316 performs mask processing with the recording data stored in the input image buffer 302b and the density information added mask data 501 of the mask buffer 302e. Thereby, appropriate image formation can be performed according to the duty of image data.

100 Inkjet recording device 102 Discharge section 103 Conveyance section 105 Carriage 201 Recording head 301 ASIC
303 PC
304 CR motor 309 CPU
310 ROM

Claims (6)

A printing apparatus that prints an image by scanning a printing means for each ink color, which is provided with a printing element array in which a plurality of printing elements for ejecting ink are arranged, a plurality of times,
a conveying means for conveying the recording medium in a direction intersecting the scanning direction of the recording means;
a counting means for counting dots of input image data for each area;
encoding means for encoding the dot count value by the counting means according to a threshold;
a comparison means for comparing adjacent dot count values;
correction means for correcting a coded value when the value encoded by the encoding means in the comparison means exceeds a set value;
storage means for storing the value encoded by the correction means;
Selection means for selecting mask data corresponding to each code value;
means for switching the mask data according to the value read from the storage means;
generation means for generating recording data using the mask data selected by the selection means;
A recording device comprising: The recording apparatus according to claim 1, wherein the dot count value is a total number of dots of a plurality of ink colors. 2. The recording apparatus according to claim 1, further comprising a control means for controlling said recording means and conveyance means so as to record an image on a recording medium based on the recording data generated by said generation means. 2. The printing apparatus according to claim 1, wherein the printing element is a printing element that ejects ink by generating thermal energy. 2. The printing apparatus according to claim 1, wherein the printing means includes a printing head provided with a plurality of printing element arrays that eject cyan, magenta, yellow, and black inks. 6. The recording apparatus according to claim 5, wherein the recording means includes the recording head and a carriage on which the recording head is mounted.

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