JP2020146953A - Printer - Google Patents

Abstract

To provide a printer which can maintain image quality of a printing image even if the cost of a sub-scanning drive unit is reduced.SOLUTION: A nozzle array includes an unused nozzle including an end nozzle, and plural use nozzles in the range used to form a printed image. Plural rasters include one or more overlap recording rasters in which a dot array is formed by plural times of main scanning including first scanning and second scanning. The plural use nozzles includes: a first overlap nozzle which impacts droplets on a specific raster, which is included one or more overlap recording rasters, in the first scanning; and a second overlap nozzle which impacts droplets on the specific raster in the second scanning. Between at least one nozzle of both overlap nozzles and an unused nozzle nearest to the afore-said one nozzle, there is a nozzle of the plural use nozzles which does not discharge droplets onto one or more overlap recording rasters.SELECTED DRAWING: Figure 4

Description

The present invention relates to a printing apparatus that ejects droplets from a plurality of nozzles included in a nozzle row.

As a printing device, a serial printer that repeats a main scan in which a recording head is moved in a main scanning direction with respect to a print substrate and a sub scan in which a print head is sent to a recording head by a paper feed mechanism is known. There is. The inkjet printer disclosed in Patent Document 1 performs partial overlap printing in which a part of a plurality of nozzles included in a nozzle array overlaps each other in two passes through one sub-scanning. Here, if the nozzle row is divided into a first region from the upper end to the middle, a second region from the lower end to the middle, and a third region between the first region and the second region, the first region to be overlapped is The average nozzle usage rate of the region and the second region is 100% in total, and the average nozzle usage rate of the third region that does not overlap is 100%. At the upper end of the printed image, the first region including the upper end and the second region including the lower end do not overlap.

Japanese Unexamined Patent Publication No. 2016-175378

If the feed accuracy of the object to be printed by the paper feed mechanism is sufficient, the printed image is formed with good image quality in both the normal portion and the upper end portion. However, in order to reduce costs, it may be required to reduce the "specs" of the paper feed mechanism, that is, the performance. In this case, at the upper end of the printed image, the feed accuracy of the printed object is lowered, so that streaks are generated and the image quality may be deteriorated.

In the printing apparatus of the present invention, the main scanning in which a plurality of nozzles are arranged in a direction different from the main scanning direction is moved relative to the printed object in the main scanning direction, and the nozzle row is described. A printing device that performs sub-scanning that moves the object to be printed relative to the sub-scanning direction, and forms a dot array of a plurality of rasters along the main scanning direction with a plurality of droplets.
The nozzle row includes an unused nozzle including an end nozzle at the end of the nozzle row and a plurality of used nozzles in the range used for forming a printed image.
The plurality of rasters include one or more overlapping recording rasters in which the dot sequence is formed by the plurality of main scans including the first scan and the second scan.
The plurality of used nozzles are a first overlap nozzle for landing the droplet in the first scan on a specific raster included in the one or more overlap recording rasters, and the first overlap nozzle for the specific raster. Including a second overlapping nozzle for landing the droplet in two scans
Between at least one of the first overlap nozzle and the second overlap nozzle and the unused nozzle closest to the one nozzle, one or more of the plurality of used nozzles are overlapped. The lap recording raster has an embodiment in which a nozzle that does not eject the droplet is present.

The figure which shows the structural example of the printing apparatus schematically. The figure which shows typically the example of the nozzle surface of a recording head. The plan view which shows typically the example of the dot sequence of the raster along the main scanning direction. The figure which shows typically the example of each nozzle allocation from the upper end processing to the normal processing. The figure which shows typically the example of each nozzle allocation from a normal process to a lower end process. The flowchart which shows the example of the print control processing performed in a printing apparatus. The figure which shows another example of each nozzle allocation from the upper end processing to the normal processing schematically.

Hereinafter, embodiments of the present invention will be described. Of course, the following embodiments merely exemplify the present invention, and not all of the features shown in the embodiments are essential for the means for solving the invention.

(1) Outline of the technique included in the present invention:
First, an outline of the technique included in the present invention will be described with reference to the examples shown in FIGS. 1 to 7. The figures of the present application are diagrams schematically showing examples, and the enlargement ratios in each direction shown in these figures may be different, and the figures may not be consistent. Of course, each element of the present technology is not limited to the specific example indicated by the reference numeral. In "Overview of the technique included in the present invention", the parentheses mean a supplementary explanation of the immediately preceding word.
Further, in the present application, the numerical range "Min to Max" means a minimum value of Min or more and a maximum value of Max or less.

Aspect 1:
As illustrated in FIG. 1, in the printing apparatus 1 according to one aspect of the present technology, a plurality of nozzles 64 are oriented in a direction different from the main scanning direction (for example, the forward direction D1 and the return direction D2) (for example, the sub-scanning direction D3). The main scan that moves the arranged nozzle rows 68 relative to the printed matter M1 in the main scanning direction (D1, D2), and the printed matter M1 that moves relative to the nozzle row 68 in the sub-scanning direction D3. The sub-scanning is performed to form a plurality of raster RA0 dot sequences DT0 along the main scanning directions (D1, D2) by the plurality of droplets 67. The nozzle row 68 includes an unused nozzle NZ2 including an end nozzle NZ2e at the end of the nozzle row 68, and a plurality of used nozzles NZ1 in the use range R1 used for forming the printed image IMp. The plurality of raster RA0s include one or more overlap recording rasters RA1 in which the dot sequence DT0 is formed by the plurality of main scans including the first scan and the second scan. The plurality of used nozzles NZ1 are a first overlap nozzle NZO1 for landing the droplet 67 on the specific raster RA2 included in the one or more overlap recording raster RA1 in the first scan, and the specific raster. It includes a second overlap nozzle NZO2 that lands the droplet 67 on the RA2 in the second scan. Of the plurality of used nozzles NZ1, the first overlapping nozzle NZO1 and at least one of the second overlapping nozzles NZO2 and the unused nozzle NZ2 closest to the one nozzle are described. There is a nozzle that does not eject the droplet 67 in one or more overlap recording raster RA1.

In the above-described aspect 1, a plurality of used nozzles NZ1 are provided between at least one nozzle of the first overlapping nozzle NZO1 and the second overlapping nozzle NZO2 and the unused nozzle NZ2 closest to the one nozzle. Since there is a nozzle that does not eject the droplet 67 in one or more overlap recording raster RA1, a plurality of nozzles 64 can be overlapped when forming the end portions (IM1, IM2) of the printed image IMp. Therefore, this aspect can provide a printing apparatus capable of maintaining the image quality of a printed image even if the cost of the sub-scanning drive unit is reduced.

Here, in order to move the recording head relative to the printed matter and to move the printed matter relative to the recording head, the recording head moves without moving the printed matter, and the recording head moves. This includes moving the material to be printed without moving, and moving both the recording head and the material to be printed. A serial printer is a typical example of a printing apparatus that performs main scanning and sub-scanning of a recording head.
Raster means an array of pixels that are linearly continuous in the main scanning direction.
A nozzle is a small hole into which a droplet is ejected.
The end nozzle means at least one of a nozzle at one end and a nozzle at the other end in the nozzle array.
The unused nozzles including the end nozzles may be only the end nozzles or may have a plurality of unused nozzles. The plurality of unused nozzles may include a plurality of nozzles within a predetermined range from the end nozzles.
The above-mentioned additional notes also apply in the following aspects.

Aspect 2:
As illustrated in FIGS. 4 and 5, the printing apparatus 1 has an end of the printed image IMp in the sub-scanning direction D3 in a state where one relative movement amount of the sub-scanning is the first relative movement amount L1. An end processing portion (for example, an upper end processing portion U1 and a lower end processing portion U2) forming a portion (for example, an upper end portion IM1 and a lower end portion IM2) may be provided. Further, the printing apparatus 1 has the end portion of the printed image IMp in a state where the relative movement amount of one sub-scanning is a second relative movement amount L2 larger than the first relative movement amount L1. A normal processing unit U3 that forms a normal unit IM3 that does not include (IM1, IM2) may be provided. The end processing units (U1, U2) may land the droplet 67 on the specific raster RA2 from the first overlap nozzle NZO1 and the second overlap nozzle NZO2. In this embodiment, when the end portions (IM1, IM2) of the printed image IMp are formed, the droplets 67 land on the specific raster RA2 from the plurality of overlapping nozzles NZO1 and NZO2, so that the cost of the sub-scanning drive unit is reduced. Can also provide a printing apparatus capable of maintaining the image quality of the edge of the printed image.

Aspect 3:
As illustrated in FIG. 7, the plurality of main scans may further include a third scan. The plurality of used nozzles NZ1 may include a third overlap nozzle NZO3 that causes the droplet 67 to land on the specific raster RA2 in the third scan. In this embodiment, since the dot sequence DT0 of the specific raster RA2 is formed by the droplets 67 ejected from the first overlap nozzle NZO1, the second overlap nozzle NZO2, and the third overlap nozzle NZO3, the driving unit for the sub-scanning It is possible to provide a printing apparatus suitable for maintaining the image quality of a printed image even if the cost is reduced.

Further, the present technology includes a print control device that controls a printing unit that performs main scanning and sub-scanning to form a dot sequence, a composite device including the above-mentioned printing device, a printing method corresponding to the above-mentioned printing device, and the above-mentioned printing control. It can be applied to a print control method corresponding to the apparatus, a print control program corresponding to the print control method, a computer-readable medium on which the print control program is recorded, and the like. Any of the devices described above may be composed of a plurality of dispersed parts.

(2) Specific example of the configuration of the printing apparatus:
FIG. 1 schematically shows a configuration example of a serial printer which is a kind of an inkjet printer as a printing apparatus 1. The printing device 1 shown in FIG. 1 includes a controller 10, a RAM 20, a non-volatile memory 30, a drive unit 50, I / F 71, 72, an operation panel 73, and the like. Here, RAM is an abbreviation for Random Access Memory, and I / F is an abbreviation for an interface. The controller 10, the RAM 20, the non-volatile memory 30, the I / F 71, 72, and the operation panel 73 are connected to the bus 80 so that information can be input and output from each other.

The controller 10 includes a CPU 11, a resolution conversion unit 41, a color conversion unit 42, a halftone processing unit 43, a rasterization processing unit 44, a drive signal transmission unit 45, and the like. CPU is an abbreviation for Central Processing Unit. The controller 10 can be configured by SoC or the like. SoC is an abbreviation for System on a Chip.

The CPU 11 is a device that mainly performs information processing and control in the printing device 1.
The resolution conversion unit 41 converts the resolution of the input image from the host device HO1, the memory card 90, or the like into the set resolution. The input image is represented by, for example, RGB data in which each pixel has an integer value of 256 gradations of R, G, and B. Here, R means red, G means green, and B means blue.

The color conversion unit 42 provides, for example, a color conversion lookup table that defines the correspondence between the gradation values of R, G, and B and the gradation values of C, M, Y, K, Lk, and LLk. With reference, RGB data of the set resolution is converted into CMYKLkLLk data having an integer value of 256 gradations of C, M, Y, K, Lk, and LLk for each pixel. Here, C means cyan, M means magenta, Y means yellow, K means black, Lk means light black with a lower concentration than K, and LLk means less than Lk. It means light light black with a lower concentration. The 256-gradation CMYKLkLLk data represents the amount of liquid 66 used, such as ink, for each pixel.
The halftone processing unit 43 performs predetermined halftone processing such as a dither method, an error diffusion method, or a density pattern method on the gradation value of each pixel constituting the CMYKLkLLk data, and determines the number of gradations of the gradation value. Reduce and generate halftone data. The halftone data is data indicating the state of dot formation, may be binary data indicating the presence or absence of dot formation, or is a multi-valued data having three or more gradations that can correspond to dots of different sizes such as small, medium, and large dots. It may be data. The binary data can be, for example, data in which 1 corresponds to dot formation and 0 corresponds to no dot. The quaternary data that can be expressed by 2 bits for each pixel can be, for example, data that corresponds to 3 for large dot formation, 2 for medium dot formation, 1 for small dot formation, and 0 without dots. .. The halftone data is an example of image data DA1 representing an image to be printed.

The rasterization processing unit 44 generates raster data by performing rasterization processing in which the halftone data is rearranged in the order in which dots are formed by the driving unit 50.
The drive signal transmission unit 45 generates a drive signal SG corresponding to the voltage signal applied to the drive element 63 of the recording head 61 from the raster data and outputs the drive signal SG to the drive circuit 62. For example, if the raster data is "dot formation", the drive signal transmission unit 45 outputs a drive signal for ejecting droplets for dot formation. Further, when the raster data is quaternary data, the drive signal transmission unit 45 outputs a drive signal for ejecting droplets for large dots if the raster data is "large dot formation", and the raster data is "medium". If it is "dot formation", it outputs a drive signal for ejecting droplets for medium dots, and if the raster data is "small dot formation", it outputs a drive signal for ejecting droplets for small dots.

Each of the above parts 41 to 45 may be composed of an ASIC, and the data to be processed may be directly read from the RAM 20 or the processed data may be directly written to the RAM 20. Here, ASIC is an abbreviation for Application Specific Integrated Circuit.
The controller 10 also acquires the accompanying data DA2 corresponding to the print mode set by the operation panel 73, the host device HO1, and the like. The accompanying data DA2 is data accompanying the halftone data which is the image data DA1, and is data that specifies the feed amount of the printed matter M1 at the time of sub-scanning, the position of the overlap nozzle, the gradation of the image data DA1, and the like. is there.

The drive unit 50 controlled by the controller 10 includes a carriage motor 51, a paper feed mechanism 53, a carriage 60, a recording head 61, and the like. The carriage motor 51 reciprocates the carriage 60 in the main scanning direction via a plurality of gears (not shown) and a belt 52. The paper feed mechanism 53 transports the printed matter M1 in the transport direction opposite to the sub-scanning direction. The carriage 60 is equipped with, for example, a recording head 61 that ejects C, M, Y, K, Lk, and LLk droplets 67. The recording head 61 includes a drive circuit 62, a drive element 63, and the like. The drive circuit 62 applies a voltage signal to the drive element 63 according to the drive signal SG input from the controller 10. As the drive element 63, a piezoelectric element that applies pressure to the liquid 66 in the pressure chamber communicating with the nozzle 64, a drive element that generates bubbles in the pressure chamber by heat and discharges the liquid droplet 67 from the nozzle 64, and the like can be used. it can. Liquid 66 is supplied to the pressure chamber of the recording head 61 from a liquid cartridge 65 such as an ink cartridge. The combination of the liquid cartridge 65 and the recording head 61 is provided in each of, for example, C, M, Y, K, Lk, and LLk. The liquid 66 in the pressure chamber is discharged as droplets 67 from the nozzle 64 toward the printed matter M1 by the driving element 63. As a result, dots of the droplet 67 are formed on the object to be printed M1 such as printing paper. While the recording head 61 moves in the main scanning direction, dots according to the raster data are formed, and the printed matter M1 is repeatedly fed in the transport direction for one sub-scanning to print on the printed matter M1. An image is formed. That is, the drive unit 50 moves the recording head 61 relative to the printed matter M1 in the main scanning direction, and moves the printed matter M1 relative to the recording head 61 in the conveying direction.

The controller 10 that controls the drive of the drive unit 50 is an example of the dot forming unit U0 that forms a dot array of rasters along the main scanning direction by repeating the main scanning a plurality of times. In the printed image, the dot forming portion U0 includes an upper end processing portion U1 forming the upper end IM1 as shown in FIG. 4, a lower end processing portion U2 forming the lower end IM2 as shown in FIG. 5, and an upper end IM1. It includes a normal processing unit U3 that forms a normal portion IM3 between the lower end portion IM2 and the lower end portion IM2. Here, the upper end portion IM1 and the lower end portion IM2 may be collectively referred to as the end portions IM1 and IM2, and the upper end processing portion U1 and the lower end processing portion U2 may be collectively referred to as the end processing portions U1 and U2.

The RAM 20 is a large-capacity, volatile semiconductor memory, and stores a program PRG2 or the like including a program that causes the printing device 1 to function as a dot forming unit U0 that forms a printed image.
The non-volatile memory 30 stores the program data PRG1 developed in the RAM 20, the parameter information 500, and the like. The parameter information 500 is an example of feed information corresponding to the accompanying data DA2, and includes the feed amount of the printed matter M1 at the time of sub-scanning, the position of the overlap nozzle, the gradation of the image data DA1, and the like. As the non-volatile memory 30, a magnetic recording medium such as a flash memory, a ROM, or a hard disk is used. Here, ROM is an abbreviation for Read Only Memory. Expanding the program data PRG1 means writing it to the RAM 20 as a program PRG2 that can be interpreted by the CPU 11.

The card I / F71 is a circuit for writing data to the memory card 90 and reading data from the memory card 90.
The communication I / F 72 is connected to the host device HO1 and inputs / outputs information to and from the host device HO1. The host device HO1 includes computers such as personal computers and tablet terminals, mobile phones such as smartphones, digital cameras, digital video cameras, and the like. The communication I / F 72 may be a wired interface such as a USB interface or a wireless communication interface according to a standard such as a short-range wireless communication system. Here, USB is an abbreviation for Universal Serial Bus. Further, the communication I / F 72 may be an interface for connecting to a wired or wireless network.

The operation panel 73 includes an output unit 74, an input unit 75, and the like, and the user can input various instructions to the printing device 1. The output unit 74 is composed of, for example, a liquid crystal panel that displays information according to various instructions and information indicating the state of the printing device 1. The output unit 74 may output these information by voice. The input unit 75 is composed of an operation input unit such as a cursor key and an enter key, for example. The input unit 75 may be a touch panel or the like that accepts operations on the display screen.

FIG. 2 schematically shows an example of the nozzle surface 61a of the recording head 61. Here, reference numeral D1 indicates a forward direction of the main scan, reference numeral D2 indicates a return direction of the main scan, reference numeral D3 indicates a sub-scanning direction, and reference numeral D4 indicates a conveying direction of the printed matter M1. Since the main scanning direction is a concept including the forward direction D1 and the backward direction D2, it may be expressed as the main scanning directions D1 and D2. The recording head 61 does not move during the sub-scanning, but for convenience, it may be indicated to move relative to the printed object M1 in the sub-scanning direction D3 opposite to the transport direction D4.

On the nozzle surface 61a shown in FIG. 2, a plurality of nozzle rows 68 having a plurality of nozzles 64 arranged at equal intervals in the sub-scanning direction D3 are arranged in the main scanning directions D1 and D2. The sub-scanning direction D3 is a direction that intersects the main scanning directions D1 and D2, and is a direction different from the main scanning directions D1 and D2. The plurality of nozzle rows 68 include a nozzle row 68C of C, a nozzle row 68M of M, a nozzle row 68Y of Y, a nozzle row 68K of K, a nozzle row 68Lk of Lk, and a nozzle row 68LLk of LLk. Each nozzle row 68 includes an unused nozzle NZ2 in an unused range R2 including an end nozzle NZ2e at the end of the nozzle row 68, and a plurality of used nozzles NZ1 in the use range R1 used for forming a printed image. I'm out. In FIG. 2, there are two unused nozzles NZ2 in the unused range R2 at the upper end portion, and two unused nozzles NZ2 in the unused range R2 at the lower end portion, which are between the two unused ranges R2. It is shown that there are a plurality of used nozzles NZ1 in the use range R1. Each used nozzle NZ1 ejects a droplet 67 toward the corresponding raster RA0. Here, among the plurality of used nozzles NZ1, each nozzle at both ends of the use range R1 is referred to as an adjacent nozzle NZ1a, and each nozzle between the two adjacent nozzles NZ1a is referred to as a non-adjacent nozzle NZ1b, and a plurality of non-adjacent nozzles. The range in which NZ1b is lined up is referred to as a non-adjacent range R3.

The recording head 61 has a nozzle row for ejecting a droplet of Lc having a concentration lower than C, a nozzle row for ejecting a droplet of Lm having a concentration lower than M, and a transparent CL droplet. It may have a nozzle row for discharging, and the like. Here, Lc means light cyan, Lm means light magenta, and CL means clear. CL droplets may be used to improve the quality of printed images.
Further, the arrangement direction of the plurality of nozzles 64 in each nozzle row 68 is not limited to the sub-scanning direction D3, and may be a direction deviated from the sub-scanning direction D3 as long as it is different from the main scanning directions D1 and D2. Further, even if a plurality of nozzles in each nozzle row are arranged in a staggered pattern, it is included in the present technology. The nozzle arrangement direction in this case means the arrangement direction of the nozzles in each row in the staggered arrangement.

FIG. 3 is a plan view schematically illustrating a plurality of raster RA0 dot sequences DT0 along the main scanning directions D1 and D2 on the printed matter M1.
Assuming that the number of passes M is an integer of 2 or more, the printing apparatus 1 performs partial overlap printing in which the dot sequence DT0 of a part of the overlap recording raster RA1 of the plurality of raster RA0s is completed by M main scans. .. One main scan means moving the recording head 61 in the forward direction D1 or the backward direction D2 over the entire printed image IMp. A path is a concept that identifies the order in which the main scans are arranged in order. The dot sequence DT0 of the raster RA0 other than the overlap recording raster RA1 is formed by one main scan. Partial overlap printing that partially overlaps the recording ranges of each pass having a certain relationship may be abbreviated as POL printing. In POL printing, in order to suppress deterioration of the image quality of the printed image due to an error in the amount of paper feed, which is the distance that the object to be printed M1 moves in the transport direction D4 in one sub-scan, the landing deviation of droplets, and the like. Will be done.
The general partial overlap printing is as follows.

The printing apparatus 1 first forms dots DT1 on a plurality of rasters RA0 in the first main scan in which the recording head 61 is moved in the forward direction D1 or the backward direction D2, and then transfers the printed matter M1 in the transport direction D4 by a predetermined amount. Perform one sub-scan to move. After that, the printing apparatus 1 repeats the main scan and the sub scan in the same manner. In the repetition of the main scan and the sub scan, the printing apparatus 1 completes the dot sequence DT0 of a part of the overlap recording raster RA1 among the plurality of raster RA0s by M main scans.

As shown in FIGS. 4 and 5, this specific example has a feature in which the overlap recording raster RA1 is set at least a part of the edges IM1 and IM2 of the printed image. Further, in this specific example, among the plurality of used nozzles NZ1 included in the nozzle row 68 shown in FIG. 2, the non-adjacent nozzles NZ1b are overlapped recording rasters even when the adjacent nozzles NZ1a are not used for recording the overlap recording raster RA1. It has the characteristics used for recording RA1.
From the above, even if the "specs" of the paper feed mechanism are lowered for cost reduction, the streaks due to the decrease in the feed accuracy of the printed object M1 at the edges IM1 and IM2 of the printed image are not noticeable, and the image quality of the printed image Is maintained.

(3) Specific example of partial overlap printing:
Next, a specific example of partial overlap printing will be described with reference to FIGS. 4 and 5.
FIGS. 4 and 5 schematically illustrate to which raster RA0 each nozzle included in the nozzle row 68 is assigned in each main scan. FIGS. 4 and 5 show how each nozzle moves relative to the relative position of pass 1 to pass 8 with the passage of time t. FIG. 4 shows the relative positions of the nozzles in the sub-scanning direction D3 in passes 1 to 8 from the start of printing the printed image IMp. Of the passes 1 to 8, passes 1 to 4 are upper end processing passes for feeding paper with a relatively short first relative movement amount L1 at the upper end IM1 of the printed image IMp, and passes 5 to 8 are passes of the printed image IMp. This is a normal processing pass for feeding paper with a relatively long second relative movement amount L2 in the normal portion IM3 of the above. FIG. 5 shows the relative positions of the nozzles in the sub-scanning direction D3 in the passes 1 to 8 until the printing of the printed image is completed. Of the passes 1 to 8, passes 1 to 5 are normal processing passes, and passes 6 to 8 are lower end processing for feeding paper with a relatively short first relative movement amount L1 at the lower end IM2 of the printed image IMp. The path. For convenience, in the sub-scanning direction D3, the end at which printing starts is called the upper end, and the end at which printing ends is called the lower end. The upper end processing is performed by the upper end processing unit U1, the lower end processing is performed by the lower end processing unit U2, and the normal processing is performed by the normal processing unit U3.

The first relative movement amount L1 of the upper end processing and the lower end processing may change depending on the number of pixels of the printed image IMp in the sub-scanning direction D3 and the like. Further, the second relative movement amount L2 of the normal processing may also be changed according to the number of pixels of the printed image IMp in the sub-scanning direction D3 and the like.

For the sake of clarity, FIGS. 4 and 5 show only one nozzle row 68 included in the recording head 61. In FIGS. 4 and 5, it is assumed that the nozzle row 68 includes 10 nozzles arranged in the sub-scanning direction D3, numbers 0 to 9 for identifying each nozzle are assigned, and unused, which is not used for forming the printed image IMp. The nozzle NZ2 is marked with a cross, and the nozzles of the plurality of used nozzles NZ1 that are not used in a specific path are shaded. The uppermost nozzle 0 and the lowermost nozzle 9 are end nozzles NZ2e at both ends of the nozzle row 68, and each end nozzle NZ2e is an unused nozzle NZ2. That is, in the nozzle row 68 shown in FIGS. 4 and 5, the use range R1 is from nozzle 1 to nozzle 8, the unused range R2 at the upper end is a range including only nozzle 0, and the unused range R2 at the lower end. Is a range including only the nozzle 9. The present technology also includes that the number of nozzles in the nozzle row is 10, but usually, the number of nozzles in the nozzle row is more than 10. Further, the first relative movement amount L1 of each sub-scan in the upper end processing and the lower end processing is equivalent to 1.5 nozzles, and the second relative movement amount L2 of each sub-scan in the normal processing is equivalent to 3.5 nozzles. Is. That is, when a certain pass is p and the pass following this pass p is p + 1, for example, when at least a part of the dot sequence is formed in the odd-numbered raster RA0 in the sub-scanning direction D3 in the pass p, the pass p + 1 At least a part of the dot sequence is formed on the even-numbered raster RA0 in the sub-scanning direction D3.

The upper end IM1 shown in FIG. 4 has 6 rasters. Each raster of the upper end IM1 is a raster in which a dot array is formed only by the nozzle 2 of the pass 3, and an overlap recording raster RA1 in which the dot array is formed by the nozzle 4 of the pass 2 and the nozzle 1 of the pass 4. , Overlap recording raster RA1 in which a dot array is formed by the nozzle 6 of the pass 1 and the nozzle 3 of the pass 3, the raster in which the dot array is formed only by the nozzle 2 of the pass 4, the nozzle 7 of the pass 1 and the nozzle 3 of the pass 3 The overlap recording raster RA1 in which a dot array is formed by the nozzle 5, and the overlap recording raster RA1 in which a dot array is formed by the nozzle 6 of the pass 2 and the nozzle 3 of the pass 4. Here, attention is paid to one specific raster RA2 included in the plurality of overlap recording raster RA1s. For convenience, among a plurality of nozzles forming a dot array on the specific raster RA2, the nozzle used first is referred to as the first overlapping nozzle NZO1, and the nozzle used next is referred to as the second overlapping nozzle NZO2. To do. In the case of the specific raster RA2 shown in FIG. 4, pass 1 is an example of the first scan, nozzle 6 of pass 1 is an example of the first overlap nozzle NZO1, and pass 3 is an example of the second scan. Nozzle 3 of 3 is an example of the second overlap nozzle NZO2. The upper end processing unit U1 lands a plurality of droplets 67 on the specific raster RA2 from both overlapping nozzles NZO1 and NZO2. Regarding the other overlap recording raster RA1, the upper end processing unit U1 has a plurality of droplets from the first overlap nozzle NZO1 in the first scan, from the second overlap nozzle NZO2 in the second scan, to the overlap recording raster RA1. Land 67.
Explaining with reference to FIG. 3, when the first droplet DR1 ejected by the first overlap nozzle NZO1 lands on the overlap recording raster RA1, the first dot DT11 is formed and the second overlap nozzle When the second droplet DR2 ejected by NZO2 lands, the second dot DT12 is formed. Here, the first droplet DR1 and the second droplet DR2 are concepts included in the droplet 67, and the first dot DT11 and the second dot DT12 are concepts included in the dot DT1. The dot sequence DT0 of the overlap recording raster RA1 shown in FIG. 3 includes a first dot DT11 and a second dot DT12.

In the normal portion IM3 shown in FIGS. 4 and 5, basically, the dot array of the overlap recording raster RA1 is formed by the nozzle 8 as the first overlap nozzle NZO1 and the nozzle 1 as the second overlap nozzle NZO2. The remaining raster dot array is formed with only one nozzle. Exceptionally, for the overlap recording raster RA1 closest to the upper end IM1 and the overlap recording raster RA1 closest to the lower end IM2, the dot sequence is nozzle 6 as the first overlap nozzle NZO1 and the second overlap nozzle NZO2. It is formed by the nozzle 1 as a. The normal processing unit U3 lands a plurality of droplets 67 on the overlap recording raster RA1 from the first overlap nozzle NZO1 in the first scan and from the second overlap nozzle NZO2 in the second scan.

The lower end IM2 shown in FIG. 5 has 6 rasters. Each raster of the lower end IM2 has dots formed from the top by the nozzle 6 of the pass 1 and the nozzle 3 of the pass 3 with the overlapping recording raster RA1, the nozzle 5 of the pass 2 and the nozzle 2 of the pass 4. Overlapping recording raster RA1 in which rows are formed, rasters in which dot rows are formed only by nozzles 7 in pass 1, overlap recording raster RA1 in which dot rows are formed by nozzles 6 in pass 2 and nozzles 3 in pass 4 , The overlap recording raster RA1 in which the dot array is formed by the nozzle 8 of the pass 1 and the nozzle 5 of the pass 3, and the raster in which the dot array is formed only by the nozzle 7 of the pass 2. Here, attention is paid to one specific raster RA2 included in the plurality of overlap recording raster RA1s. In the case of the specific raster RA2 shown in FIG. 5, pass 2 is an example of the first scan, nozzle 6 of pass 2 is an example of the first overlap nozzle NZO1, and pass 4 is an example of the second scan. Nozzle 3 of 4 is an example of the second overlap nozzle NZO2. The lower end processing unit U2 lands a plurality of droplets 67 on the specific raster RA2 from both overlapping nozzles NZO1 and NZO2. Regarding the other overlap recording raster RA1, the lower end processing unit U2 also receives a plurality of droplets from the first overlap nozzle NZO1 in the first scan and from the second overlap nozzle NZO2 in the second scan onto the overlap recording raster RA1. Land 67.

The ratio of each nozzle used to the specific raster RA2 is not particularly limited, and may be 50% or an unequal ratio such as 60% and 40%.

Here, we will compare it with the record when the "spec" of the paper feed mechanism is high. When the "spec" of the paper feed mechanism is high, one or more used nozzles NZ1 including the adjacent nozzle NZ1a adjacent to the unused nozzle NZ2 in the used range R1 are used for the overlap recording raster RA1. Further, the upper end processing paths 1 and 2 shown in FIG. 4 and the lower end processing paths 7 and 8 shown in FIG. 5 are not performed. For the upper end IM1 of the printed image, a dot sequence is formed in each raster in passes 3 and 4 by one main scan, and for the lower end IM2 of the printed image, one main scan is performed in each raster in passes 5 and 6. A row of dots is formed. High image quality edge IM1 and IM2 are formed due to the high feeding accuracy of the printed matter by the paper feeding mechanism.

However, in the above-mentioned comparative example, if the "spec" of the paper feed mechanism is lowered for cost reduction, the feed accuracy of the printed matter M1 is lowered, so that the background color of the printed matter M1 appears in the streaks and dot rows. Dark streaks may be noticeable.

In this specific example, the overlap recording raster RA1 is set at the end portions IM1 and IM2 of the printed image by performing the upper end processing passes 1 and 2 and the lower end processing passes 7 and 8. Therefore, it is difficult for the ground color streaks of the printed matter M1 and the dark streaks of the dot rows to appear. Therefore, even if the "spec" of the paper feed mechanism is lowered for cost reduction, the streaks due to the decrease in the feed accuracy of the printed object M1 at the edges IM1 and IM2 of the printed image are not conspicuous, and the image quality of the printed image is improved. Be maintained.

In order to set the overlap recording raster RA1 at the edges IM1 and IM2 of the printed image, this specific example also has the following features. That is, between at least one of the overlapping nozzles NZO1 and NZO2 and the unused nozzle NZ2 closest to the one nozzle, liquid is added to one or more overlap recording raster RA1 of the plurality of used nozzles NZ1. There is a nozzle that does not eject the drop 67. That is, at least one of the overlapping nozzles NZO1 and NZO2 is a non-adjacent nozzle NZ1b that is not adjacent to the unused nozzle NZ2. For example, the unused nozzle NZ2 closest to the overlap nozzle 3 of the path 3 shown in FIG. 4 is nozzle 0, and any of the plurality of overlap recording raster RA1s between the unused nozzle 0 and the overlap nozzle 3 There is a nozzle that does not eject the droplet 67. Further, the unused nozzle NZ2 closest to the overlap nozzle 6 of the path 6 shown in FIG. 5 is the nozzle 9, and any of the plurality of overlap recording raster RA1s between the unused nozzle 9 and the overlap nozzle 6 can be used. There is a nozzle that does not eject the droplet 67.

As described above, since there is a used nozzle NZ1 that does not eject the droplet 67 on one or more overlap recording raster RA1 between the nearest unused nozzle NZ2 and the overlap nozzle, this specific example is a printed image. A plurality of nozzles can be overlapped when forming the end portions IM1 and IM2. As a result, the background color streaks of the printed object M1 and the dark streaks of the dot rows are suppressed, and the image quality of the printed image can be maintained even if the cost of the sub-scanning drive unit is reduced.

(4) Specific example of print control processing:
FIG. 6 illustrates a print control process performed by the controller 10 of the printing apparatus 1 shown in FIG. This processing corresponds to the dot forming unit U0 including the end processing units U1 and U2 and the normal processing unit U3.

When the halftone processing unit 43 of the controller 10 generates the image data DA1 which is the halftone data, the print control process shown in FIG. 6 starts. First, the controller 10 acquires the accompanying data DA2 in S102. The accompanying data DA2 is data for specifying the print mode set in the image data DA1, and is data for specifying necessary information from the parameter information 500 stored in the non-volatile memory 30.

After acquiring the accompanying data DA2, the controller 10 acquires the parameter information corresponding to the accompanying data DA2 in S104. For example, the controller 10 uses the parameter information 500 stored in the non-volatile memory 30 to obtain the relative movement amounts L1 and L2 of the object to be printed M1 during the sub-scanning, the positions of the overlap nozzles NZO1 and NZO2, and the image data DA1. Acquire necessary information such as gradation.

After acquiring the parameter information, the controller 10 acquires partial data required for one main scan from the image data DA1 after halftone in S106. For example, the controller 10 stores the raster data corresponding to the plurality of used nozzles NZ1 in the current path in the image data DA1 as partial data in the RAM 20. Of course, the upper end IM1 of the printed image is dotted by the nozzle used for recording among the nozzle rows 68 located at the positions corresponding to the respective passes 1 to 4 of the relatively short first relative movement amount L1 shown in FIG. Partial data corresponding to the formed raster is acquired. The normal portion IM3 of the printed image is dot-formed by the nozzles used for recording among the nozzle rows 68 located at the positions corresponding to the respective passes of the relatively long second relative movement amount L2 shown in FIGS. The partial data corresponding to the raster is acquired. The lower end IM2 of the printed image is dot-formed by the nozzles used for recording among the nozzle rows 68 located at positions corresponding to the respective passes 6 to 8 of the relatively short first relative movement amount L1 shown in FIG. Partial data corresponding to the raster is acquired. Further, the controller 10 masks the partial data corresponding to the overlap recording raster RA1 according to the usage ratio of the overlap nozzles NZO1 and NZO2, so that the partial data corresponding to the usage ratio of the overlap nozzles NZO1 and NZO2 can be obtained. Convert.

After acquiring the partial data, the controller 10 passes the acquired partial data to the drive signal transmission unit 45 shown in FIG. 1 in S108, and instructs the drive unit 50 to drive the recording head 61. Then, the drive unit 50 causes the recording head 61 to perform the main scan once, and during that time, the drive signal transmission unit 45 ejects droplets to each nozzle 64 of the recording head 61. As a result, dots are formed in the portion of the printed image corresponding to the partial data to be formed on the printed matter M1. Further, the drive unit 50 feeds the printed matter M1 once. That is, one sub-scan is performed.

From the above, the controller 10 as the upper end processing unit U1 lands a plurality of droplets 67 from the overlap nozzles NZO1 and NZO2 on the overlap recording raster RA1 as the upper end processing of the first relative movement amount L1, and the rest. A plurality of droplets 67 are landed on the raster of the above from one nozzle NZ1. The controller 10 as the normal processing unit U3 lands a plurality of droplets 67 from the overlap nozzles NZO1 and NZO2 on the overlap recording raster RA1 as the normal processing of the second relative movement amount L2, and causes the remaining rasters to land. On the other hand, a plurality of droplets 67 are landed from one nozzle used NZ1. The controller 10 as the lower end processing unit U2 lands a plurality of droplets 67 from the overlap nozzles NZO1 and NZO2 on the overlap recording raster RA1 as the lower end processing of the first relative movement amount L1, and causes the remaining rasters to land. On the other hand, a plurality of droplets 67 are landed from one nozzle used NZ1.

After that, in S110, the controller 10 branches the process depending on whether or not the image data DA1 has been acquired until the end of the page. The controller 10 returns the process to S106 when the image data DA1 is not acquired until the end of the page, and ends the print control process when the image data DA1 is acquired until the end of the page.

As described above, between at least one of the overlapping nozzles NZO1 and NZO2 and the unused nozzle NZ2 closest to the one nozzle, one or more of the plurality of used nozzles NZ1 overlap recording raster. There is a nozzle in RA1 that does not eject the droplet 67. As a result, in this specific example, a plurality of nozzles can be overlapped when forming the end portions IM1 and IM2 of the printed image, and the background color streaks of the printed matter M1 and the dark streaks of the dot rows are unlikely to appear. In this specific example, even if the "spec" of the sub-scanning drive unit is lowered for cost reduction, the streaks due to the lowering of the feed accuracy of the printed object M1 at the edges IM1 and IM2 of the printed image are not conspicuous, and printing is performed. The image quality of the image can be maintained.

(5) Modification example:
Various modifications of the present invention can be considered.
For example, in the printing apparatus 1 shown in FIG. 1, at least a part of the resolution conversion unit 41, the color conversion unit 42, and the halftone processing unit 43 may be in the host device HO1. In this case, the printing device 1 may receive the halftone data from the host device HO1, and the rasterization processing unit 44 may perform the print control processing shown in FIG. 6 using the halftone data as the image data DA1. Further, the rasterization processing unit 44 may be in the host device HO1.

In FIGS. 4 and 5, the two unused ranges R2 of each nozzle row 68 include only the end nozzle NZ2e, but the unused range R2 is adjacent to the end nozzle NZ2e as shown in FIG. It may be a range up to a nozzle, or may be a range including three or more nozzles. It should be noted that one of the two unused ranges R2 of the nozzle row 68 may be omitted.
Further, the number of overlapping nozzles forming a dot array on one overlap recording raster RA1 is not limited to two, and may be three or more.

FIG. 7 schematically shows an example in which three overlap nozzles NZO1, NZO2, and NZO3 are assigned to one overlap recording raster RA1 in the upper end processing. In the upper end processing shown in FIG. 7, one pass is added as compared with the upper end processing shown in FIG. 4, and among the passes 1 to 9 shown in FIG. 7, passes 1 to 5 are paper having the first relative movement amount L1. The upper end processing pass for feeding is performed, and the paths 6 to 9 are the lower end processing paths for feeding the paper with the second relative movement amount L2. Of the upper end IM1s for the six rasters shown in FIG. 7, the second, third, fifth, and sixth rasters from the top are the overlap recording raster RA1. Of these overlap recording rasters RA1, overlap nozzles NZO1, NZO2, and NZO3 are assigned to the top specific raster RA2. For convenience, of the plurality of nozzles forming a dot array on the specific raster RA2, the first nozzle used is called the first overlap nozzle NZO1, the second nozzle used is called the second overlap nozzle NZO2, and the last one is called. The nozzle used for the above will be referred to as a second overlap nozzle NZO3. In the case of the specific raster RA2 shown in FIG. 7, pass 1 is an example of the first scan, nozzle 7 of pass 1 is an example of the first overlap nozzle NZO1, and pass 3 is an example of the second scan. Nozzle 4 of 3 is an example of the second overlap nozzle NZO2, pass 5 is an example of the third scan, and nozzle 1 of pass 5 is an example of the third overlap nozzle NZO3. The upper end processing unit U1 lands a plurality of droplets 67 on the specific raster RA2 from the overlap nozzles NZO1, NZO2, and NZO3. In addition, if the overlap nozzles NZO1, NZO2, and NZO3 can be assigned to one overlap recording raster RA1 on the upper end IM1, the upper end processing unit U1 can assign the overlap nozzles NZO1, NZO2 to the overlap recording raster RA1. , NZO3 lands a plurality of droplets 67.

Of course, also in the lower end processing, three overlapping nozzles NZO1, NZO2, and NZO3 are assigned to one overlap recording raster RA1 by adding one or more passes as compared with the lower end processing shown in FIG. Can be done. In this case, the lower end processing unit U2 makes a plurality of droplets 67 land on one overlap recording raster RA1 from the overlap nozzles NZO1, NZO2, and NZO3.

At the edges IM1 and IM2 of the printed image, when the dot sequence of one overlap recording raster RA1 is formed by a plurality of droplets 67 ejected from three or more overlapping nozzles, the feed accuracy of the printed matter M1 is improved. The streaks caused by the lowering become less noticeable. Therefore, the above-mentioned example is suitable for maintaining the image quality of the printed image even if the cost of the sub-scanning drive unit is reduced.

(6) Conclusion:
As described above, according to the present invention, it is possible to provide a technique such as a printing apparatus capable of maintaining the image quality of a printed image even if the cost of the sub-scanning drive unit is reduced, according to various aspects. Of course, the above-mentioned basic actions and effects can be obtained even with a technique consisting of only the constituent requirements according to the independent claims.
In addition, the configurations disclosed in the above-mentioned examples are mutually replaced or the combinations are changed, the known techniques and the respective configurations disclosed in the above-mentioned examples are mutually replaced or the combinations are changed. It is also possible to implement the above-mentioned configuration. The present invention also includes these configurations and the like.

1 ... Printing device, 10 ... Controller, 20 ... RAM, 30 ... Non-volatile memory, 41 ... Resolution conversion unit, 42 ... Color conversion unit, 43 ... Halftone processing unit, 44 ... Rasterize processing unit, 45 ... Drive signal transmission unit , 50 ... drive unit, 61 ... recording head, 64 ... nozzle, 67 ... droplet, 68 ... nozzle row, D1 ... forward direction, D2 ... return direction, D3 ... sub-scanning direction, D4 ... transport direction, DT0 ... dot row , DT1 ... dot, IMp ... printed image, IM1, IM2 ... end, IM3 ... normal part, L1 ... first relative movement amount, L2 ... second relative movement amount, M1 ... printed matter, NZ1 ... nozzle used, NZ1a ... adjacent nozzle, NZ1b ... non-adjacent nozzle, NZ2 ... unused nozzle, NZ2e ... end nozzle, NZO1 ... first overlap nozzle, NZO2 ... second overlap nozzle, NZO3 ... third overlap nozzle, R1 ... range of use , R2 ... unused range, R3 ... non-adjacent range, RA0 ... raster, RA1 ... overlap recording raster, RA2 ... specific raster, U0 ... dot forming section, U1, U2 ... edge processing section, U3 ... normal processing section.

Claims (3)

A main scan in which a plurality of nozzles are arranged in a direction different from the main scanning direction is moved relative to the printed object in the main scanning direction, and the printed object is moved in the sub-scanning direction with respect to the nozzle array. A printing device that performs sub-scanning that moves relative to each other and forms a dot array of a plurality of rasters along the main scanning direction with a plurality of droplets.
The nozzle row includes an unused nozzle including an end nozzle at the end of the nozzle row and a plurality of used nozzles in the range used for forming a printed image.
The plurality of rasters include one or more overlapping recording rasters in which the dot sequence is formed by the plurality of main scans including the first scan and the second scan.
The plurality of used nozzles are a first overlap nozzle for landing the droplet in the first scan on a specific raster included in the one or more overlap recording rasters, and the first overlap nozzle for the specific raster. Including a second overlapping nozzle for landing the droplet in two scans
Between at least one of the first overlap nozzle and the second overlap nozzle and the unused nozzle closest to the one nozzle, one or more of the plurality of used nozzles are overlapped. A printing device in which a nozzle that does not eject the droplet is present in the lap recording raster. An edge processing unit that forms an end portion of the printed image in the sub-scanning direction in a state where one relative movement amount of the sub-scanning is the first relative movement amount.
A normal processing unit that forms a normal portion of the printed image that does not include the end portion in a state where the relative movement amount of one sub-scanning is a second relative movement amount larger than the first relative movement amount. And with
The printing apparatus according to claim 1, wherein the edge processing unit lands the droplets on the specific raster from the first overlap nozzle and the second overlap nozzle. The plurality of main scans further include a third scan.
The printing apparatus according to claim 1 or 2, wherein the plurality of used nozzles include a third overlap nozzle that causes the droplets to land on the specific raster in the third scan.

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