JP2016132150A - Printing control device and printing control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique capable of accelerating a printing operation complementing the defect of a dot to be formed due to a defective nozzle.SOLUTION: There is provided a printing control device U0 in which plural nozzles 64 discharging the droplet (ink droplet 67) for forming a dot DT, and a material M1 to be printed are relatively moved in a relative movement direction D2, and complemental nozzles RN forming to a second raster RA2, complemental dots DT2, DT3 complementing the defective dot of a first raster RA1 due to defective nozzles LN are included in the plural nozzles 64. The device comprises a printing control part U1 which controls the discharge of the droplet (67) from the complemental nozzles RN in the unit R1 of N pixels (N is an integer of 2 or more) continuing in the relative movement direction D2 in the second raster RA2 and also controls to M times (M is an integer larger than N but smaller than 2N), the maximum number of times for discharging the droplet (67) from the complemental nozzles RN to N pixels of the second raster RA2.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a print control apparatus and a print control method.

  The ink jet printer, for example, relatively moves a plurality of nozzles arranged in a predetermined nozzle arrangement direction and a printing material in a relative movement direction intersecting the nozzle arrangement direction, and inks from the nozzles according to nozzle data representing the presence or absence of dots for each pixel. Drops (droplets) are ejected to form dots on the substrate. If ink droplets are not ejected from the nozzles due to clogging, etc., or if the ejected ink droplets do not draw the correct trajectory, a `` dot missing '' area in which pixels where dots are not formed is connected in the relative movement direction is formed, and the printed image is white. Muscles such as muscles are generated. In order to suppress this streak, a complementary dot that complements a dot to be formed by a defective nozzle in which dot formation is defective is formed by a complementary nozzle. For example, if there is a normal dot such as a medium dot in the pixel where the complementary dot is formed, the complementary dot is formed by changing the normal dot to a larger dot (for example, a large dot).

  In the image recording apparatus disclosed in Patent Document 1, when a block including at least a non-ejection port (configured by a plurality of ejection ports) is set, dots of image data to be recorded by the block exist. According to the ratio and dot continuity, it is set whether the block of interest is driven with a normal heat pulse or a complementary heat pulse. When driven by the complementary heat pulse, the ink discharge amount increases from 14 pl to 17 pl, and the dot size increases from φ60 μm to φ65 μm.

JP 2004-9531 A

  When the dot size is increased in order to complement the dots to be formed by the defective nozzle, the time required for the ejection waveform included in the drive signal becomes longer. Such a problem similarly exists in various printing apparatuses.

  In view of the above, one of the objects of the present invention is to provide a technique capable of speeding up printing for complementing dots to be formed by defective nozzles.

In order to achieve one of the above objects, the present invention is a printing control apparatus for a printing unit in which a plurality of nozzles that discharge droplets forming dots and a printing material relatively move in a relative movement direction.
The plurality of nozzles includes a complementary nozzle that forms complementary dots on the second raster to complement the dots of the first raster to be recorded by the defective nozzle,
In the second raster, discharge of droplets from the complementary nozzle is controlled in units of N pixels (N is an integer of 2 or more) continuous in the relative movement direction, and the N pixel of the second raster is supplemented with the complementary pixel. It has an aspect including a print control unit that sets the maximum number of times that droplets are ejected from a nozzle to M times (M is an integer larger than N and smaller than 2N).

  In the second raster, the discharge of droplets from the complementary nozzle is controlled in units of N pixels (N is an integer of 2 or more) continuous in the relative movement direction in the second raster, and the second raster In this aspect, the maximum number of droplets ejected from the complementary nozzle to N pixels is set to M times (M is an integer larger than N and smaller than 2N).

  The aspect mentioned above can provide the technique which can speed up the printing which complements the dot which should be formed with a defective nozzle.

  Furthermore, the present invention provides a printing apparatus including a printing control apparatus, a printing method including a printing control method, a printing control program for causing a computer to realize functions corresponding to the above-described components, a printing program including the printing control program, and the like The present invention can be applied to a computer-readable medium on which a program is recorded. The aforementioned apparatus may be composed of a plurality of distributed parts.

FIG. 3 is a diagram schematically illustrating an example of an electrical block configuration of a printing apparatus. FIG. 3 is a diagram schematically illustrating a configuration example of a main part of a printing apparatus. FIG. 3 is a diagram schematically illustrating an example of an electrical block configuration of a recording head. The figure which shows the example of the correspondence of a nozzle and a pixel typically. (A) is a figure which illustrates typically the principal part of a printing apparatus, (b) is a figure which shows typically the example of the electromotive force curve based on the residual vibration of a diaphragm. (A) is a figure which shows the example of an electrical circuit of a defective nozzle detection unit, (b) is a figure which shows typically the example of the output signal from an amplifier. The figure which shows typically the example of the relationship of a drive signal, a latch signal, a channel signal, and a printing timing signal. The figure which shows the example of the data before and behind complementation typically. The figure which shows typically the example of the correspondence of a partial drive signal and a virtual drive signal. FIG. 6 is a diagram schematically illustrating an example of print data transfer timing and structure. (A)-(d) is a figure which shows the example of a dot complement typically. The figure which shows typically the example of the relationship of a drive signal, a latch signal, a channel signal, and a printing timing signal in a modification. The figure which shows typically the example of the transfer timing and structure of print data of the printing apparatus which concerns on a modification. The figure which shows typically the example of the relationship of a drive signal, a latch signal, a channel signal, and a printing timing signal in a modification. FIG. 6 is a diagram schematically illustrating an example of a relationship among a drive signal, a latch signal, a channel signal, and a print timing signal in a comparative example. The figure which shows the data before and behind complementation typically in a comparative example.

  Embodiments of the present invention will be described below. Of course, the following embodiments are merely examples of the present invention, and all the features shown in the embodiments are not necessarily essential to the means for solving the invention.

(1) Overview of this technology:
First, an overview of the present technology will be described with reference to FIGS. 1 to 14 are schematic views, and the drawings may not be consistent.

  In the printing apparatus (printing unit) 1 illustrated in FIG. 4 and the like, a plurality of nozzles 64 that eject droplets (for example, ink droplets 67) that form dots DT and the printing material M1 relatively move in the relative movement direction D2. . The plurality of nozzles 64 include complementary nozzles RN that form complementary dots DT2 and DT3 that complement the dots of the first raster RA1 to be recorded by the defective nozzle LN in the second raster RA2. The print control unit U1 controls the discharge of the droplet (67) from the complementary nozzle RN in a unit R1 of N pixels (N is an integer of 2 or more) continuous in the relative movement direction D2 in the second raster RA2. In addition, the maximum number of times that the droplet (67) is ejected from the complementary nozzle RN to the N pixels of the second raster RA2 is M times (M is an integer greater than N and smaller than 2N).

FIG. 15 shows the relationship among the drive signal COM, the latch signal LAT, the channel signal CH, and the print timing signal PTS used in the printing apparatus according to the comparative example.
Here, the drive signal COM during the period of one pixel has ejection waveforms P91 and P92 representing the timing of ejecting ink droplets from the nozzles. If the dots are not complemented, only the ejection waveform P91 for ejecting the ink droplets of the normal dot DT91 (middle dot) may be supplied to the complementary nozzle drive element. The original data DA91 shown in FIG. 16 indicates that the drive signal COM for one pixel is only the ejection waveform P91 for forming a medium dot unless dots are complemented. In order to complement the dot to be formed by the defective nozzle, if the normal dot DT91 is present in the pixel in which the complementary dot is formed, the normal dot DT91 needs to be changed to a larger complementary dot (large dot). is there. When the complementary discharge waveform P92 is supplied to the complementary nozzle drive element together with the normal dot discharge waveform P91, a large dot is formed. Therefore, a complementary discharge waveform P92 is also provided in the drive signal COM during the period of one pixel. The supplementary data DA92 in FIG. 16 indicates that the drive signal COM for one pixel becomes the ejection waveforms P91 and P92 for forming a large dot. The normal dot ejection waveform P91 and the complementary ejection waveform P92 have the same shape.

The latch signal LAT defines the latch timing of the print data and becomes H (high), that is, active once during one pixel period. The channel signal CH defines the selection timing of the complementary ejection waveform P92 included in the drive signal COM, and becomes H (high), that is, active once during one pixel period. The print timing signal PTS is generated from the encoder pulse output from the encoder, and defines the generation start timing of the drive signal COM. The print timing signal PTS is H (high), that is, active once during the period of one pixel. The discharge waveforms P91 and P92 are repeatedly generated in units of one pixel where the print timing signal PTS is H.
As described above, when performing dot complementation, as shown in FIGS. 15 and 16, ejection waveforms P91 and P92 capable of ejecting ink droplets from the complement nozzle twice during the period of one pixel are necessary for the drive signal COM. The maximum number of times that an ink droplet is ejected from a complementary nozzle to a pixel is two. During the period of two pixels, the ejection waveforms P91 and P92 that can eject ink droplets from the complementary nozzle four times are necessary for the drive signal COM, and the maximum number of times that ink droplets are ejected from the complementary nozzle to two pixels is 4. Times. Note that the maximum number of times that ink droplets are ejected from the complementary nozzle to two pixels is four means that there are a maximum of four planned landing positions of ink droplets on two pixels.

  On the other hand, as illustrated in FIGS. 4 and 7 and the like, the present technology is a unit R1 of N pixels (N is an integer of 2 or more) continuous in the relative movement direction D2 in the second raster RA2 recorded by the complementary nozzle RN. Thus, the discharge of the droplet (67) from the complementary nozzle RN is controlled. In addition, the maximum number of times that the droplet (67) is discharged from the complementary nozzle RN to the N pixels of the second raster RA2 is M times (M is an integer larger than N and smaller than 2N). The maximum number of times that the ink droplets are ejected from the complementary nozzle to the N pixel is M times means that there are M positions where the ink droplets are expected to land on the N pixel at the maximum. For example, when N = 2, M = 3. In this case, the maximum number of times that the liquid droplet (67) is ejected from the nozzle 64 during the period of two pixels is three, which is smaller than in the comparative examples shown in FIGS. If simply calculated, the printing time can be reduced to 3/4. Therefore, the present technology can speed up printing that complements dots to be formed by defective nozzles. In addition, as shown in FIG. 16, if dot complementation is performed for each pixel of the second raster RA2, there is a possibility that overcomplementation that the second raster RA2 becomes too dark may occur. However, an ink droplet is applied to the N pixels of the second raster RA2. Is reduced to M times (1 <M / N <2), so that overcomplementation can be suppressed.

Here, the droplets include uncolored droplets such as droplets that improve image quality.
A nozzle is a small hole through which droplets are ejected.
A print substrate is a material that holds a printed image. The shape is generally rectangular, but there are round shapes (for example, optical disks such as CD-ROM and DVD), triangles, squares, polygons, etc., and at least JIS (Japanese Industrial Standards) P0001: 1998 (paper / paperboard) And pulp and paper products) and all processed products. Resin sheets, metal plates, three-dimensional objects, etc. are also included in the substrate.
The relative movement of the plurality of nozzles and the substrate includes the movement of the substrate without moving the plurality of nozzles, the movement of the plurality of nozzles without moving the recording substrate, and the plurality of nozzles. And the movement of both the substrate and the substrate. A representative example of a printing apparatus in which a plurality of nozzles move without moving a plurality of nozzles when droplets are ejected to form dots includes a line printer.
Poor ejection of droplets includes clogging, which is a phenomenon that the nozzle is blocked.
A raster means an array of pixels that are linearly continuous in the relative movement direction.
Pixels are the smallest elements of an image that can be assigned colors independently.

  By the way, the print control unit U1 discharges the droplet (67) from the normal nozzle NN to N pixels in the raster RA3 recorded by the normal nozzle NN excluding the complementary nozzle RN among the plurality of nozzles 64. The number of times may be set to N times. In this aspect, since the maximum number of times the droplet (67) is ejected to the N pixels in the raster recorded by the nozzles 64 other than the complementary nozzle RN is N times, the dots to be formed by the defective nozzle are complemented. A technology capable of realizing high-quality printing can be provided.

  The print control unit U1 applies the complementary nozzle RN to the N pixel of the second raster RA2 when the complementary dot DT3 is formed by overlapping a droplet (67) on the pixel included in the N pixel of the second raster RA2. The maximum number of times the liquid droplet (67) is ejected may be M times. In this embodiment, when the droplet (67) is overlapped on the pixels included in the N pixel to form the complementary dot DT3, the maximum number of times the droplet (67) is ejected to the N pixel is M times. It is possible to provide a technology capable of realizing high-quality printing while complementing the dots to be formed by the nozzles.

The print control unit U1 may include a drive signal generation unit U2 that generates a drive signal COM having an ejection waveform P0 that represents a timing at which the drive element 51 ejects droplets (67) from the nozzles 64. In the drive signal COM, the timing at which the ejection waveform P0 appears may be repeated in the unit R1 of the N pixels. The printing control unit U1 may set the maximum number of times that the ejection waveform P0 is supplied to the driving element 51 of the complementary nozzle RN during the N pixel period TA to the M times. In this aspect, the maximum number of times that the ejection waveform P0 is supplied during the period TA of the N pixels of the second raster RA2 recorded by the complementary nozzle RN is M times (M is an integer larger than N and smaller than 2N). is there. For example, when N = 2, M = 3. For this reason, the maximum number of times that the ejection waveform is supplied during the period of two pixels is three, which is smaller than that in the comparative example shown in FIG. Therefore, this aspect can provide a suitable print control device that speeds up printing that complements dots to be formed by defective nozzles.
Here, the ejection waveform means a driving waveform having a voltage change for ejecting droplets from the nozzle, and does not mean a driving waveform in which droplets are not ejected from the nozzle.

  The printing control unit U1 performs the N pixel period TA of the raster RA3 recorded by the normal nozzle NN with respect to the drive element 51 of the normal nozzle NN excluding the complementary nozzle RN among the plurality of nozzles 64. The maximum number of times that the discharge waveform P0 is supplied may be N times. In this aspect, since the maximum number of times the ejection waveform P0 is supplied during the period TA of N pixels in the raster recorded by the nozzles 64 other than the complementary nozzle RN is N times, the dots to be formed by the defective nozzle are complemented. However, it is possible to provide a technology capable of realizing high-quality printing.

  As exemplified in FIG. 9 and the like, the drive signal generation unit U2 has a discharge waveform P1 representing a timing at which the N droplets (67) are discharged from the normal nozzle NN during the period TA of the N pixels. The first partial drive having a part of the discharge waveform P0 including the discharge waveform P2 representing the timing of discharging the M droplets (67) from the complementary nozzle RN during the period TA of the N pixels. You may have the partial drive signal generation part U20 which produces | generates signal COM A and the 2nd partial drive signal COM B which has a remainder. The print control unit U1 is configured such that the maximum number of times during the period TA of the N pixels is N times or M times based on at least one of the first partial drive signal COM A and the second partial drive signal COM B. The discharge waveform P0 may be supplied to the drive element 51 of the nozzle 64. This aspect can provide a print control apparatus that can easily supply a discharge waveform having the maximum number of N times or M times during a period of N pixels.

  Also, as illustrated in FIG. 12 and the like, the drive signal generation unit U2 discharge waveforms representing the timing at which the M droplets (67) are discharged from the complementary nozzle RN during the period TA of the N pixels. The complementary drive signal COM R having P2 may be generated. The print control unit U1 may change the N discharge waveforms P1 included in the M discharge waveforms P2 of the complementary drive signal COM R to a discharge waveform that is supplied to the drive element 51 of the normal nozzle NN. . In this aspect, since the N discharge waveforms P1 included in the M discharge waveforms P2 of the complementary drive signal COM R are changed to the discharge waveforms supplied to the drive element 51 of the normal nozzle NN, a circuit for generating a drive signal Can be provided.

  In the N discharge waveforms P1 included in the M discharge waveforms P2 of the complementary drive signal COM R, the discharge speeds of the droplets (67) from the normal nozzle NN are different from each other. A waveform (for example, discharge waveform P21) and a second speed discharge waveform (for example, discharge waveform P23) may be included. This aspect can provide a technique capable of realizing high-quality printing by changing the discharge speed of the droplet (67) from the normal nozzle NN while complementing the dots to be formed by the defective nozzle.

(2) Specific example of configuration of printing apparatus:
FIG. 1 schematically illustrates a configuration example of a line printer which is a kind of ink jet printer as the printing apparatus 1. As shown in FIG. 4, the printing apparatus 1 includes a printing unit in which the nozzle 64 and the printing material M1 relatively move in the relative movement direction D2, and a print control device U0 that controls the printing unit. As will be described in detail later, the print control device U0 controls the ejection of the ink droplets 67 from the complementary nozzle RN in units of N pixels R1 in the complementary raster RA2, and ink from the complementary nozzle RN to the N pixels of the complementary raster RA2. A printing control unit U1 that sets the maximum number of times the droplet 67 is ejected to M times is provided. Note that a printing apparatus to which the present technology can be applied may be a serial printer or the like having a carriage on which a recording head for ejecting ink droplets is mounted, a copying machine, a facsimile, or a multifunction machine having these functions. Examples of the ink used in the ink jet printer that forms a color image include C (cyan), M (magenta), Y (yellow), and K (black) inks. Of course, the ink may further include Or (orange), Gr (green), uncolored ink for improving image quality, and the like.

  FIG. 2 schematically illustrates a configuration example of the control unit 46, the operation panel 73, the recording head 100, and the like. FIG. 3 shows an example of the electrical configuration of the head 100 incorporated in the printing apparatus 1. Here, illustration of the control logic 57 and the level shifter 58 is omitted. FIG. 4 schematically shows an example of the correspondence relationship between the nozzle 64 and the pixel PX. Reference numeral D1 indicates the direction in which the nozzles 64 are arranged, reference numeral D2 indicates the relative movement direction between the nozzles 64 and the printing medium M1, and reference numeral D3 is orthogonal (intersects) to the conveyance direction (D2) of the printing medium M1. The width direction is shown. In FIG. 4, the arrangement direction D1 and the width direction D3 coincide with each other, but directions different from each other are also included in the present technology. In FIG. 4, the directions D1 and D3 and the relative movement direction D2 are orthogonal to each other. However, if the directions are different from each other, the directions are included in the present technology.

First, the electrical configuration of the printing apparatus 1 will be described with reference to FIGS.
As shown in FIG. 1, the printing apparatus 1 generally includes a main body 2 and a head unit 3 attached to the main body 2. The head unit 3 is electrically connected to the main body 2 via an FFC (flexible flat cable) 99.

  The main body 2 includes a paper feed mechanism 41, an encoder 42, interfaces (I / F) 43 and 49, a RAM (Random Access Memory) 44, a ROM (Read Only Memory) 45, an oscillation circuit 47, a control unit 46, and a drive signal generation circuit. 48 (drive signal generation unit U2), and the like.

The paper feed mechanism 41 includes, for example, a paper feed motor and a paper feed roller, and transports the printing material M1 in the relative movement direction D2.
The encoder 42 is attached to, for example, a paper feed motor, and generates an encoder pulse corresponding to the position of the substrate M1 in the relative movement direction D2. This encoder pulse is input to the control unit 46.

The RAM 44 is used as an input buffer, an output buffer, a work memory, and the like. The received print data DA1 is temporarily stored in the input buffer. In the output buffer, the print data SI developed from the print data DA1 is temporarily stored.
In the ROM 45, various control routines executed by the control unit 46, font data, graphic functions, various procedures, and the like are written.

The oscillation circuit 47 generates a clock signal CK having a predetermined frequency.
The control unit 46 refers to the font data and graphic function in the ROM 45 and develops the print data DA1 in the input buffer into the multi-bit print data SI and stores it in the output buffer. This print data SI is transmitted to the head unit 3 via the internal I / F 49. The print data SI may be transmitted to the head unit 3 after being subjected to at least one of compression processing and encryption processing in the main body 2. In this case, the head unit 3 may perform the process described later on the print data SI after performing at least one of the decompression process and the decryption process. Further, the control unit 46 generates a print timing signal PTS (see FIG. 7) from the encoder pulse generated by the encoder 42 and supplies it to the drive signal generation circuit 48. The print timing signal PTS is a signal that determines the generation start timing of the ejection waveform that is repeated in the drive signal COM generated by the drive signal generation circuit 48. Further, for example, the control unit 46 generates a latch signal LAT and a channel signal CH based on the clock signal CK from the oscillation circuit 47 and supplies the latch signal LAT and the channel signal CH to the head unit 3 through the internal I / F 49.

FIG. 2 shows a configuration example of the control unit 46. The control unit 46 includes a CPU (Central Processing Unit) 46a, a resolution conversion unit 46b, a color conversion unit 46c, a halftone processing unit 46d, a complementing unit 46e, a print signal transmission unit 46f, and the like. The control unit 46 can be configured by SoC (System on a Chip) or the like.
The CPU 46 a is a device that mainly performs information processing and control in the printing apparatus 1.

The resolution conversion unit 46b converts the resolution of the input image from the host device H1 or the like into the set resolution. For example, the input image is represented by RGB data having an integer value of 256 gradations of RGB (red, green, blue) in each pixel.
For example, the color conversion unit 46c converts RGB data of a set resolution into CMYK data having an integer value of 256 gradations of CMYK for each pixel.

The halftone processing unit 46d performs predetermined halftone processing such as a dither method, an error diffusion method, and a density pattern method on the gradation values of each pixel constituting the CMYK data, thereby obtaining the number of gradations of the gradation value. The original data DA11 (see FIG. 8) before being reduced and complementing the dots to be formed by the defective nozzle LN is generated. The original data DA11 is data representing the dot formation status, and may be binary data representing the presence / absence of dot formation, or multi-level data of three or more gradations that can correspond to dots of different sizes such as large, medium, and small dots. But you can. The original data DA11 shown in FIG. 8 is binary data representing whether or not medium dots are formed.
The complement unit 46e generates complement data DA12 (see FIG. 8) in which dots are complemented to the complement raster RA2 (see FIG. 4) based on the original data DA11. The complementary data DA12 is also data representing the dot formation status. The complementary data DA12 shown in FIG. 9 is multivalued data of three or more gradations including no dots, medium dot formation, and large dot formation.

The print signal transmission unit 46f generates print data SI including N pixel data SIN and pattern data SP based on the complementary data DA12, and outputs a signal such as the print data SI to the drive circuit 52 of the head 100.
Each of the above-described units 46b to 46f may be configured by an ASIC (Application Specific Integrated Circuit), and may directly read data to be processed from the RAM 44 or directly write processed data into the RAM 44.

  The drive signal generation circuit 48 (drive signal generation unit U2) generates a drive signal COM having a discharge waveform P0 (see FIG. 9) indicating the timing at which the drive element 51 discharges ink droplets (droplets) 67 from the nozzles 64. . The discharge waveform P0 is a general term for all discharge waveforms described later. The drive signal COM is repeated in a unit R1 of N pixels in which the timing at which the ejection waveform P0 appears is continuous in the relative movement direction D2 as shown in FIG. The drive signal generation circuit 48 generates a drive signal COM having an ejection waveform of a unit R1 of N pixels in accordance with the print timing signal PTS, and supplies it to the head unit 3 through the internal I / F 49. 2 and 9 includes a partial drive signal generation unit U20 that generates a first partial drive signal COM A and a second partial drive signal COM B as the drive signals COM. Details of the drive signal generation circuit 48 will be described later. As shown in FIG. 4, the head unit 3 forms dots DT by ejecting ink droplets 67 from the nozzles 64 in units of N pixels R1. Note that each pixel included in the N pixels is defined as a pixel N1, a pixel N2,. When N = 2, adjacent pixels N1 and N2 are included in the N pixels.

The head unit 3 includes a drive element 51, a drive circuit 52, a defective nozzle detection unit 70 (defective nozzle detection unit U3), and the like. The drive circuit 52 includes a shift register 54, a latch circuit 55, a control logic 57, a decoder 56, a level shifter 58, a switch circuit 59, and the like. The drive elements 51 are provided for the number of nozzles 64 used for printing, and the drive circuits 52 are provided for the number of nozzle rows 68. The defective nozzle detection unit 70 constitutes a defective nozzle detection unit U3 that detects whether the state of each nozzle 64 is normal or defective.
The driving element 51 shown in FIGS. 1 to 3 is a piezo element (piezoelectric element) that applies pressure to the ink (liquid) 66 communicating with the nozzle 64, and generates bubbles in the pressure chamber by heat. In addition, a drive element that discharges ink droplets from the nozzles can also be used. Ink 66 is supplied from an ink cartridge (liquid cartridge) 65 to the pressure chamber of the head 100. The combination of the ink cartridge 65 and the head 100 is provided in each of CMYK, for example. The ink 66 in the pressure chamber is ejected as an ink droplet 67 from the nozzle 64 toward the substrate M1 by the drive element 51 deforming the wall of the pressure chamber in accordance with the voltage of the supplied drive signal COM. Thereby, the dot DT of the ink droplet 67 is formed in the to-be-printed material M1, such as printing paper. When the substrate M1 is conveyed in the relative movement direction D2, that is, when the nozzle 64 and the substrate M1 are relatively moved, a print image corresponding to the complementary data DA12 is formed by a plurality of dots DT.

The print data SI from the main body 2 is serially transmitted from the I / F 49 to the shift register 54 in synchronization with the clock signal CK. For example, as shown in FIG. 10, the print data SI includes N pixel data SIN representing a pattern of dots formed on consecutive N pixels, and pattern data SP. The N pixel data SIN is data representing the dot formation status (no dot, medium dot formation, or large dot formation) of each pixel included in the N pixel. In order to express the N pixel data SIN shown in FIG. The pattern data SP is data for converting the N pixel data SIN into pulse selection information corresponding to the ejection waveforms P11, P21, P22, and P23 shown in FIG.
When a latch signal LAT is input from the main body 2, the latch circuit 55 latches the N pixel data SIN transmitted to the shift register 54.

The control logic 57 latches the pattern data SP transmitted to the shift register 54 and supplies it to the decoder 56 together with the channel signal CH from the main body 2.
The decoder 56 outputs the N pixel data SIN latched by the latch circuit 55 based on the pattern data SP, the latch signal LAT, and the channel signal CH from the control logic 57 to the ejection waveforms P11, P21, and P22 shown in FIG. , P23 to pulse selection information. Here, for the N pixel shown in FIG. 4, the dot formation status of the pixel N1 (no dot, medium dot formation, or large dot formation) is “A”, and the dot formation status of the pixel N2 (no dot or , Medium dot formation) is represented by “B”, and the dot formation status of the pixels N1 and N2 is represented by “AB”. “M” means medium dot formation, which is different from the maximum number M. For example, as shown in FIG. 10, “00” (“0” is no dot) is converted into pulse selection information (0000) without an ejection waveform, and “0M” (“M” is medium dot formation) is ejected waveform. It is converted into pulse selection information (0001) for selecting only P23, “M0” is converted into pulse selection information (1000) for selecting only the discharge waveform P11, and “MM” is a pulse for selecting the discharge waveforms P11 and P23. It is converted into selection information (1001), “L0” (“L” is large dot formation) is converted into pulse selection information (0110) for selecting the discharge waveforms P21 and P22, and “LM” is converted into the discharge waveforms P21 and P22. , P23 is converted into pulse selection information (0111) to be selected. In the print data, the ink droplets 67 ejected by the ejection waveforms P21 and P22 both land on the pixel N1 and become large dots. The decoder 56 outputs a pulse selection signal SGP corresponding to the pulse selection information to the level shifter 58. The pulse selection signal SGP corresponding to the pulse selection information “1” is a signal for supplying the corresponding ejection waveform to the driving element 51, and the pulse selection signal SGP corresponding to the pulse selection information “0” represents the corresponding ejection waveform as the driving element. 51 is a signal that is not supplied to 51. During the period TA of N pixels, the decoder 56 outputs a pulse selection signal SGP corresponding to the ejection waveforms P11, P21, and P22 to the level shifter 58 at the first latch timing, and ejects the waveform at the second latch timing. A pulse selection signal SGP corresponding to P23 is output to the level shifter 58.

The level shifter 58 generates a voltage for driving the switch circuit 59 based on the pulse selection signal SGP from the decoder 56.
The switch circuit 59 switches whether to supply the ejection waveforms P11, P21, P22, and P23 to the drive element 51 based on the drive voltage from the level shifter 58.

  FIG. 3 shows an example of the electrical configuration of the recording head 100 for ejecting ink droplets using the print data SI shown in FIG. As described above, the control logic 57 and the level shifter 58 are not shown. The print data SI including the N pixel data SIN and the pattern data SP is transmitted to the shift register 54. The N pixel data SIN from the shift register 54 is latched by the latch circuit 55 when the latch signal LAT is input, and is input to the decoder 56. The pattern data SP from the shift register 54 is latched by the control logic 57 when the latch signal LAT is input, and is input to the decoder 56 together with the channel signal CH. The decoder 56 converts the input N pixel data SIN into pulse selection information corresponding to each ejection waveform P11, P21, P22, P23, and outputs a corresponding pulse selection signal SGP to the level shifter 58. For the pulse selection signal SGP corresponding to the pulse selection information “1”, the level shifter 58 drives the switch circuit 59 so as to supply the corresponding ejection waveform to the driving element 51, and the pulse corresponding to the pulse selection information “0”. For the selection signal SGP, the switch circuit 59 is driven so that the corresponding ejection waveform is not supplied to the drive element 51.

  The printing apparatus 1 illustrated in FIG. 2 includes an operation panel 73 having an output unit 74, an input unit 75, and the like, and a user can input various instructions to the printing apparatus 1. The output unit 74 includes, for example, a liquid crystal panel (display unit) that displays information corresponding to various instructions and information indicating the state of the printing apparatus 1. The output unit 74 may output the information as a voice. The input unit 75 includes, for example, operation keys (operation input unit) such as a cursor key and a determination key. The input unit 75 may be a touch panel that accepts an operation on the display screen.

  Next, an example of the correspondence between the nozzle 64 and the pixel PX will be described with reference to FIG. The head unit 3 shown in FIG. 4 includes a recording head 100 having a C nozzle row 68C, an M nozzle row 68M, a Y nozzle row 68Y, and a K nozzle row 68K. The head 100 may be provided for each color of CMYK. The nozzle rows 68C, 68M, 68Y, and 68K are arranged in the transport direction (relative movement direction D2) of the substrate M1 such as printing paper. In each nozzle row 68C, 68M, 68Y, 68K, the nozzles 64C, 64M, 64Y, 64K are arranged in the arrangement direction D1. The nozzle rows 68C, 68M, 68Y, and 68K are collectively referred to as the nozzle row 68, and the nozzles 64C, 64M, 64Y, and 64K are collectively referred to as the nozzle 64.

  In the nozzle row 68, there may be a defective nozzle LN in which ink droplets are not ejected or the ejected ink droplets do not draw a correct trajectory due to clogging or the like. When there is a defective nozzle LN, a missing raster (first raster) RA1 in which the dot missing pixel PXL in which no dot DT is formed is connected in the relative movement direction D2 is formed on the printing material M1. Unless the dots to be formed on the defective nozzle LN are complemented, streaks such as the ground color (for example, white) of the printing material M1 are generated in the print image along the relative movement direction D2 due to the missing raster RA1.

In the present technology, the rasters that are adjacent to the missing raster RA1 in the width direction D3 are referred to as complementary rasters (second rasters) RA2a and RA2b, respectively. The secondary neighboring rasters RA2c and RA2d are called nozzles, and the nozzles that form dots in the complementary rasters RA2a and RA2b are called complementary nozzles RN. The complementary nozzle RN is a nozzle that forms complementary dots DT2 and DT3 in the complementary raster RA2 that complement the dots of the missing raster RA1 to be recorded by the defective nozzle LN. The complementary nozzle RN is a nozzle that ejects ink droplets of the same color as the defective nozzle LN. Specifically, when there is a defective nozzle LN in the C nozzle row 68C, the complementary nozzle RN is selected from the C nozzle 64C, and when the defective nozzle LN is in the M nozzle row 68M, the complementary nozzle RN is M. When the defective nozzle LN is selected from the Y nozzle row 68Y and the defective nozzle LN is selected from the Y nozzle 64Y, the complementary nozzle RN is selected when the defective nozzle LN is selected from the K nozzle row 68K. Are selected from the K nozzles 64K.
Also, as shown in FIG. 4, when the pitch Np of the nozzles 64 in the arrangement direction D1 is the same as the pitch of the pixels PX in the width direction D3, the nozzles adjacent to the defective nozzle LN in the arrangement direction D1 become complementary nozzles RN. . Note that the complementary rasters RA2a and RA2b are collectively referred to as a complementary raster RA2. The nozzles excluding the complementary nozzle RN among the plurality of nozzles 64 are referred to as normal nozzles NN, and the raster in which dots are formed by the normal nozzles NN is referred to as normal raster RA3. Although the secondary neighboring rasters RA2c and RA2d in this specific example are included in the normal raster RA3, the secondary neighboring rasters RA2c and RA2d, and further, the third neighboring rasters and the like may be included in the complementary raster RA2. Further, the present technology also includes, for example, the secondary neighboring rasters RA2c and RA2d as complementary rasters instead of the rasters adjacent to the missing raster RA1 as complementary rasters.

FIGS. 5A and 5B are diagrams for explaining an example of a method in which the defective nozzle detection unit 70 detects the state of the nozzle 64, and FIG. 5A schematically shows the main part of the printing apparatus 1. FIG. 5B schematically shows an electromotive force curve VR based on the residual vibration of the diaphragm 510. FIG. 6A shows an example of an electric circuit of the detection unit 70, and FIG. 6B schematically shows an example of an output signal from the comparator 701b.
In the flow path substrate 610 of the head 100 shown in FIG. 5A, the ink 66 flows from the pressure chamber 611, the ink supply path 612 through which the ink 66 flows from the ink cartridge 65 to the pressure chamber 611, and the ink 66 from the pressure chamber 611 to the nozzle 64. A flowing nozzle communication path 613 and the like are formed. As the flow path substrate 610, for example, a silicon substrate or the like can be used. The surface of the flow path substrate 610 is a diaphragm portion 514 that constitutes a part of the wall surface of the pressure chamber 611. The diaphragm 514 can be made of, for example, silicon oxide. The diaphragm 510 can be constituted by, for example, a diaphragm part 514, a driving element 51 formed on the diaphragm part 514, and the like. The drive element 51 includes, for example, a lower electrode 511 formed on the vibration plate portion 514, a piezoelectric layer 512 substantially formed on the lower electrode 511, and an upper electrode 513 substantially formed on the piezoelectric layer 512. A piezoelectric element or the like can be used. For example, platinum or gold can be used for the electrodes 511 and 513. For the piezoelectric layer 512, for example, a ferroelectric perovskite oxide such as PZT (lead zirconate titanate, Pb (Zr _x , Ti _1-x ) O _{3 in} stoichiometric ratio) can be used.

FIG. 5A is a block diagram showing the main part of the printing apparatus 1 provided with the detection unit 70 that detects the electromotive force state from the piezoelectric element (driving element 51) based on the residual vibration of the diaphragm 510. FIG. One end of the detection unit 70 is electrically connected to the lower electrode 511, and the other end of the detection unit 70 is electrically connected to the upper electrode 513.
FIG. 5B illustrates an electromotive force curve (electromotive force state) VR of the drive element 51 based on the residual vibration of the diaphragm 510 generated after the supply of the drive signal SG for ejecting the ink droplet 67 from the nozzle 64. Yes. Here, the horizontal axis represents time t, and the vertical axis represents electromotive force Vf. The electromotive force curve VR shows an example in which the ink droplet 67 is ejected from the normal nozzle 64. If the ink droplet 67 does not eject from the nozzle due to clogging or the like, or the ejected ink droplet 67 does not draw a correct locus, the electromotive force curve deviates from VR. Therefore, it is possible to detect whether the nozzle 64 is normal or defective by using a detection circuit as shown in FIG.

  The detection unit 70 shown in FIG. 6A includes an amplification unit 701 and a pulse width detection unit 702. The amplifying unit 701 includes, for example, an operational amplifier 701a, a comparator 701b, capacitors C1 and C2, and resistors R1 to R5. When the drive signal SG output from the drive circuit 52 is applied to the drive element 51, residual vibration occurs, and an electromotive force based on the residual vibration is input to the amplifying unit 701. The low frequency component included in the electromotive force is removed by a high-pass filter composed of a capacitor C1 and a resistor R1, and the electromotive force after the removal of the low frequency component is amplified by the operational amplifier 701a at a predetermined amplification factor. The output of the operational amplifier 701a passes through a high-pass filter composed of a capacitor C2 and a resistor R4, is compared with a reference voltage Vref by a comparator 701b, and is either high level H or low level depending on whether it is higher than the reference voltage Vref. It is converted into a pulse voltage of L.

FIG. 6B shows an example of a pulse voltage output from the comparator 701 b and input to the pulse width detector 702. The pulse width detection unit 702 resets the count value when the input pulse voltage rises, increments the count value every predetermined period, and outputs the count value to the control unit 46 as a detection result when the next pulse voltage rises. Output. The count value corresponds to the cycle of the electromotive force based on the residual vibration, and the sequentially output count value indicates the frequency characteristic of the electromotive force based on the residual vibration. The frequency characteristic (for example, cycle) of the electromotive force when the nozzle is the defective nozzle LN is different from the frequency characteristic of the electromotive force when the nozzle is normal. Therefore, the control unit 46 can determine that the detection target nozzle is normal if the sequentially input count value is within the allowable range, and if the sequentially input count value is outside the allowable range, the detection target. It can be determined that these nozzles are defective nozzles LN.
By performing the processing described above for each nozzle 64, the control unit 46 can grasp the state of each nozzle 64 and can store information representing the position of the defective nozzle LN in a memory such as the RAM 44.

  Of course, the detection of the defective nozzle LN is not limited to the method described above. For example, the ink droplet 67 is ejected while sequentially switching the target nozzle from the plurality of nozzles 64, and an operation input of information (for example, a nozzle number) for identifying a nozzle on which no dot is formed on the printing material M1 is accepted. Included in detection. Further, if information for identifying the defective nozzle LN is stored in, for example, a nonvolatile memory before shipping from the manufacturing factory, it is not necessary to provide the defective nozzle detection unit U3 in the printing apparatus 1.

  When the defective nozzle LN is detected, the position of the missing raster RA1 can be determined. As shown in FIG. 4, the complementary raster RA2 and the complementary nozzle RM for complementing the dots to be formed in the missing raster RA1 are determined and complemented. Dots DT2 and DT3 can be formed. As shown in FIG. 4 and the like, the print control unit U1 of the present technology applies the ink droplet 67 from the complementary nozzle RN in a unit R1 of N pixels (N is an integer of 2 or more) continuous in the relative movement direction D2 in the complementary raster RA2. As shown in FIG. 7 and the like, the maximum number of ejections of the ink droplet 67 from the complementary nozzle RN to the N pixels of the complementary raster RA2 is set to M times (M is an integer satisfying N <M <2N). To do. That is, M / N is larger than 1 and smaller than 2, and is not an integer. For example, when N = 2 and M = 3, the printing control apparatus U0 adds complementary ink droplet ejection to either of two consecutive pixels in the complementary raster RA2, thereby adding the complementary ink droplets. The print data is controlled so that complementary dot data is generated in the ejected pixels. Thereby, it is possible to speed up dot complementing while ensuring the resolution of normal printing.

FIG. 7 schematically shows an example of the relationship among the drive signal COM, the latch signal LAT, the channel signal CH, and the print timing signal PTS. The drive signal COM shown in FIG. 7 is divided into virtual drive signals COM1 and COM2 for convenience. In the case where the print controller U1 of this specific example ejects the ink droplet 67 from the nozzle 64 to N pixels (for example, N = 2) at most N times, the first partial drive signal COM A and the second partial drive signal COM shown in FIG. Based on B, a discharge waveform P1 of N times at maximum during the period TA of N pixels is supplied to the drive element 51 of the nozzle 64 including at least the normal nozzle NN. The interval between the repeated discharge waveforms P1 is made uniform (for example, 1200 dpi). Further, the print control unit U1 of this specific example, based on the second partial drive signal COM B shown in FIG. 9, when ejecting the ink droplets 67 from the complementary nozzle RN at the maximum M times (for example, M = 3) to the N pixels. During the period TA of N pixels, a maximum of M ejection waveforms P2 are supplied to the drive element 51 of the complementary nozzle RN. Note that the interval between the repeated discharge waveforms P2 may be equal (for example, 1800 dpi) or may not be equal.
From the above, the first drive signal COM1 indicates a virtual drive signal having ejection waveforms P1a and P1b for ejecting the ink droplet 67 from the nozzle 64 including at least the normal nozzle NN to N pixels at most N times, and the second drive signal COM2 is A virtual driving signal having ejection waveforms P2a, P2b, and P2c for ejecting ink droplets 67 at maximum M times from the complementary nozzle RN to N pixels is shown. Of course, actually generating the first drive signal COM1 and the second drive signal COM2 is also included in the present technology. Note that the second drive signal COM2 shown in FIG. 7 is the second partial drive signal COMB itself shown in FIG.

  When the dots are not complemented, the ejection waveforms P1a and P1b are supplied to the drive element 51. During the period TA of N pixels, the latch signal LAT that defines the latch timing of the print data SI is H (high), that is, active before each of the ejection waveforms P1a and P1b. Accordingly, the latch signal LAT is activated N = 2 times for each printing timing signal PTS. On the other hand, the intervals of the N latch signals LAT are made uneven in consideration of the timing of the complementary discharge waveform P2b. In the latch signal LAT shown in FIG. 7, the interval T1 between the first latch timing and the second latch timing is longer than the interval T2 between the second latch timing and the first latch timing in the next period TA (for example, T1: T2 = 7: 3). When the ejection waveforms P1a and P1b are supplied to the drive element 51, the channel signal CH is not used.

  As described above, when the print data SI forms medium dots in the pixels N1 and N2, the pulse selection signal SGP corresponding to the ejection waveform P1a is transmitted from the decoder 56 to the level shifter 58 at the first latch timing, and the ejection waveform P1a. At the same time, the ink droplet 67 is ejected from the nozzle 64, and a medium dot is formed as the normal dot DT1 in the pixel N1. At the second latch timing, the pulse selection signal SGP corresponding to the ejection waveform P1b is transmitted from the decoder 56 to the level shifter 58, the ink droplet 67 is ejected from the nozzle 64 in accordance with the ejection waveform P1b, and the normal dot DT1 is output to the pixel N2. As a result, medium dots are formed.

  When large dots that complement the medium dots to be formed by the defective nozzle LN are formed in the complementary raster RA2, the ejection waveforms P2a, P2b, and P2c are supplied to the drive element 51. During the period TA of N pixels, the latch signal LAT that defines the latch timing of the print data SI is H (high), that is, active before the ejection waveforms P2a and P2c. The channel signal CH for switching the ejection waveforms P2a and P2b becomes H (high), that is, active before the ejection waveform P2b.

  As described above, when the print data SI forms a large dot in the pixel N1 and a medium dot in the pixel N2, the pulse selection signal SGP corresponding to the ejection waveforms P2a and P2b is sent from the decoder 56 to the level shifter at the first latch timing. 58, the ink droplet 67 is ejected from the nozzle 64 in accordance with the ejection waveforms P2a and P2b, and a large dot is formed as the complementary dot DT3 (see FIG. 4) in the pixel N1. At the second latch timing, the pulse selection signal SGP corresponding to the ejection waveform P2c is transmitted from the decoder 56 to the level shifter 58, the ink droplet 67 is ejected from the nozzle 64 in accordance with the ejection waveform P2c, and a medium dot is formed in the pixel N2. It is formed.

  FIG. 8 schematically shows an example of data for performing dot complementation using the drive signal COM described above. The original data DA11 before dot complement is binary data representing the presence / absence of medium dot formation. The complement data DA12 after the dot complement is multi-value data of three or more gradations including no dot “0”, medium dot formation “M”, and large dot formation “L”. In the original data DA11, when the data of the N pixel of the complement raster RA2 is “MM”, if dot complement is not performed, medium dots are formed in the pixels N1 and N2 according to the drive waveform P1 of the first drive signal COM1. become. When the data of the N pixel of the complementary raster RA2 in the complementary data DA12 is “LM”, a large dot (complementary dot DT3 shown in FIG. 4) is formed in the pixel N1 according to the drive waveform P2 of the second drive signal COM2, and the pixel N2 A medium dot is formed on the surface.

FIG. 9 shows an example of a correspondence relationship between actual partial drive signals COM A and COMB and drive signals COM1 and COM2. The drive signal generation circuit 48 (partial drive signal generation unit U20) includes a first partial drive signal COM A having a part of the ejection waveform P0 obtained by combining the ejection waveforms P1 and P2, and a second partial drive signal COM having the remaining part. B. The ejection waveform P1 is a generic term for ejection waveforms P1a and P1b that represent the timing of ejecting N ink droplets 67 from the normal nozzle NN during a period TA of N pixels. The ejection waveform P2 is a generic term for ejection waveforms P2a, P2b, and P2c that represent the timing at which M ink droplets 67 are ejected from the complementary nozzle RN during the period TA of N pixels. The first partial drive signal COM A has a partial ejection waveform P1a among the ejection waveforms P1a, P1b, P2a, P2b, and P2c. That is, the discharge waveform P11 of the first partial drive signal COM A corresponds to the discharge waveform P1a. The second partial drive signal COM B has the remaining discharge waveforms P1b, P2a, P2b, and P2c among the discharge waveforms P1a, P1b, P2a, P2b, and P2c. That is, in the second partial drive signal COM B, the discharge waveform P21 corresponds to the discharge waveform P2a, the discharge waveform P22 corresponds to the discharge waveform P2b, and the discharge waveform P23 corresponds to the discharge waveforms P1b and P2c. It should be noted that the intervals between the discharge waveforms P11, P23, P11, P23... Repeated in both partial drive signals COM A, COM B are made uniform (for example, 1200 dpi). The interval of the ejection waveform P2 repeated in the second partial drive signal COM B may be equal (for example, 1800 dpi) or may not be equal.
As described above, the print control unit U1 of the present specific example, based on at least one of the first partial drive signal COM A and the second partial drive signal COM B, discharge waveforms having the maximum number of N times during the period TA of N pixels. It is possible to supply P1 to at least the driving element 51 of the normal nozzle NN and supply the ejection waveform P2 having the maximum number of M times during the period TA of N pixels to the driving element 51 of the complementary nozzle RN.

  Whether or not the ejection waveforms P11, P21, P22, and P23 included in the partial drive signals COM A and COM B are supplied to the drive element 51 can be selected according to the pattern data SP as shown in FIG. 10, for example. FIG. 10 schematically shows an example of the transfer timing and structure of the print data SI. The pattern data SP shown in FIG. 10 is bit data indicating whether or not to supply each ejection waveform P11, P21, P22, P23 to the drive element 51. Bit data “0” means that no discharge waveform is supplied, and bit data “1” means that a discharge waveform is supplied. In the example of FIG. 10, multi-value data “00” of N pixels corresponds to pattern data “0000”, multi-value data “0M” of N pixels corresponds to pattern data “0001”, and multi-value data of N pixels. “M0” corresponds to pattern data “1000”, multi-value data “MM” of N pixels corresponds to pattern data “1001”, and multi-value data “L0” of N pixels corresponds to pattern data “0110”. , N pixel multi-value data “LM” corresponds to pattern data “0111”. Of course, the structure of the pattern data SP is not limited to the example shown in FIG.

  As described above, when the multi-value data of the N pixel is “00”, the ejection waveform is not supplied to the drive element 51 and no dot is formed in the pixels N1 and N2. When the multi-value data of the N pixel is “0M”, only the ejection waveform P23 is supplied to the drive element 51, and a medium dot is formed in the pixel N2. When the multi-value data of the N pixel is “M0”, only the ejection waveform P11 is supplied to the drive element 51, and a medium dot is formed in the pixel N1. When the multi-value data of N pixels is “MM”, ejection waveforms P11 and P23 are supplied to the drive element 51, and medium dots are formed in the pixels N1 and N2. When the multi-value data of the N pixel is “L0”, the ejection waveforms P21 and P22 are supplied to the drive element 51, and a large dot is formed in the pixel N1. When the multi-value data of N pixels is “LM”, ejection waveforms P21, P22, and P23 are supplied to the drive element 51, a large dot is formed in the pixel N1, and a medium dot is formed in the pixel N2. When the original data DA11 is binary data indicating whether or not medium dots are formed, the medium dots formed in the normal raster RA3 are normal dots DT1, and the large dots formed in the complementary raster RA2 are complementary dots DT3. The medium dots formed in the complementary raster RA2 include a normal dot DT1 and a complementary dot DT2. This is because the medium dot formed when the data “M” representing medium dot formation in the original data DA11 becomes the multi-value data “M” as it is, is the normal dot DT1, and the data representing no dot in the original data DA11. This is because the medium dot formed when “0” is replaced with the multi-value data “M” is the complementary dot DT2. Therefore, in FIG. 10, both codes DT <b> 1 and DT <b> 2 are attached to the medium dots formed in the pixel (N <b> 1 or N <b> 2) where “M” is present in the N pixel data SIN. The same applies to FIG. 13 described later.

  The large dot is formed when the complementary dot DT3 is formed by overlapping the ink droplet 67 on the pixel included in the N = 2 pixel of the complementary raster RA2, specifically, the multi-value data of the N pixel is “ This is the case of “L0” or “LM”. In this case, it can be seen that the maximum number of times that the ink droplet 67 is ejected from the complementary nozzle RN to the N pixels of the complementary raster RA2 is M = 3. Note that the maximum number of ink droplets ejected from the complementary nozzle to N = 2 pixels is M = 3 means that there are a maximum of M = 3 spots where ink droplets will land on N = 2 pixels. means. On the other hand, when the large dot is not formed, specifically, when the multi-value data of N pixel is “00”, “0M”, “M0”, or “MM”, the nozzle is set to the N pixel of the normal raster RA3 or the complementary raster RA2. It can be seen that the maximum number of ejections of the ink droplet 67 from 64 is N = 2. Note that the maximum number of times that the ink droplets are ejected from the complementary nozzle to N = 2 pixels is N = 2 times that there are a maximum of N = 2 planned landing positions of the ink droplets on N = 2 pixels. means.

  FIGS. 11A to 11D schematically show an example of dot complementing when a large dot can be formed only in the pixel N1 among the N pixels in order to match the ejection waveforms P11, P21, P22, and P23. Yes. 11A to 11D show an example in which complementary dots DT2 and DT3 that complement the dots to be formed on the defective nozzle LN are formed on the complementary rasters RA2a and RA2b.

As in the original data DA11 shown in FIG. 11A, when the pixel N1 of the missing raster RA1 is “M” and the pixel N1 of the complementary raster RA2 is “0”, the pixel of the complementary raster RA2 of the complementary data DA12. “M” is stored in N1, and a medium dot is formed as a complementary dot DT2 in this pixel N1.
When the pixel N1 of the missing raster RA1 is “M” and the pixel N1 of the complementary raster RA2 is “M” as in the original data DA11 illustrated in FIG. 11B, the pixel of the complementary raster RA2 of the complementary data DA12. “L” is stored in N1, and a large dot is formed as a complementary dot DT3 in this pixel N1. When “M” is stored in the pixel N2, the ejection waveform P2 is supplied to the driving element 51 of the complementary nozzle RN at the maximum M = 3 times during the period TA of N pixels.

When the pixel N2 of the missing raster RA1 is “M” and the pixel N2 of the complementary raster RA2 is “0” as in the original data DA11 illustrated in FIG. 11C, the pixel of the complementary raster RA2 of the complementary data DA12. “M” is stored in N2, and a medium dot is formed as a complementary dot DT2 in this pixel N2.
When the pixel N2 of the missing raster RA1 is “M” and the pixel N2 of the complementary raster RA2 is “M” as in the original data DA11 illustrated in FIG. 11D, the pixel of the complementary raster RA2 of the complementary data DA12. “L” cannot be stored for N2. Therefore, “M” is stored in the pixel N2 of the complementary raster RA2 of the complementary data DA12, and a medium dot is formed as the normal dot DT1 in this pixel N2.

  As described above, in this specific example, the ejection of the ink droplet 67 from the complementary nozzle RN is controlled in the unit R1 of N = 2 pixels continuous in the relative movement direction D2 in the complementary raster RA2 recorded by the complementary nozzle RN. The In addition, the maximum number of times that the ink droplet 67 is ejected from the complementary nozzle RN to N = 2 pixels of the complementary raster RA2 is M = 3. In order to form complementary dots, as shown in FIGS. 15 and 16, it is not necessary to set the maximum number of times that the ink droplet 67 is ejected from the complementary nozzle RN to N = 2 pixels of the complementary raster RA2 is 2 × N = 4. If simply calculated, the printing time can be reduced to 3/4. Therefore, in this specific example, it is possible to speed up printing for complementing dots to be formed by defective nozzles. Compared with the comparative example shown in FIG. 16, in this specific example, the maximum number of times ink droplets are ejected to the N pixels of the complementary raster RA2 is reduced to M times (1 <M / N <2). Overcomplementation can be suppressed.

(3) Modification:
Various modifications can be considered for the present invention.
For example, the nozzle array of the recording head may be a nozzle array in which the nozzles are arranged in a staggered manner, a nozzle array in which a plurality of nozzles are arranged in a direction inclined from the conveyance direction of the printing material, or the like. Further, the head unit may be a head unit for a serial printer, in addition to the head unit for a line printer. Accordingly, the complementary nozzle is not limited to the nozzle adjacent to the defective nozzle in the nozzle alignment direction D1, and may be a nozzle that is not adjacent to the defective nozzle in the nozzle alignment direction D1.
The active of the print timing signal PTS, the latch signal LAT, and the channel signal CH may be L (low).

In the above-described embodiment, the large dot (complementary dot DT3) is not formed on the pixel N2 but formed on the pixel N1, but the large dot (complementary dot DT3) is not formed on the pixel N1 but on the pixel N2. Also good.
In the above-described embodiment, even when the complementary raster is used, when a large dot (complementary dot DT3) is not formed in the N pixel, a discharge waveform based on the discharge waveform P1 of the maximum number N times is supplied to the drive element of the complementary nozzle. However, a discharge waveform based on the discharge waveform P2 of the maximum number of times M may always be supplied to the drive element 51 of the complementary nozzle RN. In this case, it is only necessary to supply a maximum N discharge waveforms to the drive element 51 among the M discharge waveforms P2.

Further, the ejection of ink droplets from the normal nozzle NN and the complementary nozzle RN may be controlled using one drive signal without using the partial drive signals COM A and COM B.
FIG. 12 schematically shows an example of the relationship among the drive signal COM, the latch signal LAT, the channel signal CH, and the print timing signal PTS in the modification. The drive signal generation circuit 48 (drive signal generation unit U2) of this specific example has a complementary drive signal having a discharge waveform P2 that represents the timing at which M ink droplets 67 are discharged from the complementary nozzle RN during the period TA of N pixels. COMR is generated. The print control unit U1 of this specific example uses the discharge waveform P1 included in the M discharge waveforms P2 of the complementary drive signal COM R as a discharge waveform supplied to the drive element 51 of the normal nozzle NN. FIG. 12 shows a virtual first drive signal COM1 having N discharge waveforms P21 and P23 included in the M discharge waveforms P2 of the complementary drive signal COMR. Of course, the present technology also includes actually generating the first drive signal COM1. In the case where the print controller U1 of this specific example causes the N pixels (for example, N = 2) to eject the ink droplet 67 from the nozzle 64 at most N times, the print control unit U1 includes the maximum included in the M ejection waveforms P2 of the complementary drive signal COM R. The N discharge waveforms P1 are supplied to the drive element 51 of the nozzle 64 including at least the normal nozzle NN. Further, in the case where the print control unit U1 of this specific example ejects the ink droplets 67 from the complementary nozzle RN at the maximum M times (for example, M = 3) to the N pixel, the discharge waveform P2 at the maximum of the complementary drive signal COM R. Is supplied to the drive element 51 of the complementary nozzle RN.

  The intervals of the N latch signals LAT are made uneven in consideration of the timing of the complementary discharge waveform P22. In the latch signal LAT shown in FIG. 12, the interval T1 between the first latch timing and the second latch timing is longer than the interval T2 between the second latch timing and the first latch timing in the next period TA (for example, T1: T2 = 7: 3). For this reason, if the speed of the ink droplet 67 ejected from the normal nozzle NN is the same by the ejection waveforms P21 and P23, the position of the normal dot DT1 to the pixel N2 is shifted toward the next N pixel.

  Therefore, the amplitude of the subsequent discharge waveform (second-speed discharge waveform) P23 is made larger than the amplitude of the previous discharge waveform (first-speed discharge waveform) P21, and discharge is performed from the normal nozzle NN by the subsequent discharge waveform P23. The velocity Vm2 of the ink droplet 67 is made faster than the velocity Vm1 of the ink droplet 67 ejected from the normal nozzle NN by the previous ejection waveform P21. Thereby, the position of the normal dot DT1 on the pixel N2 is matched with the position of the pixel N2, and high-quality printing is realized.

  Of the M discharge waveforms P21, P22, and P23, when the second discharge waveform P22 and the third discharge waveform P23 are changed to the N discharge waveform P1, the previous discharge waveform (first speed discharge waveform). ) The amplitude of P22 may be larger than the amplitude of the subsequent discharge waveform (second speed discharge waveform) P23. In this case, the velocity Vm1 of the ink droplet 67 ejected from the normal nozzle NN by the previous ejection waveform P22 is faster than the velocity Vm2 of the ink droplet 67 ejected from the normal nozzle NN by the subsequent ejection waveform P23. Thereby, the position of the normal dot DT1 on the pixel N1 is adjusted to the position of the pixel N1, and high-quality printing is realized.

  FIG. 13 schematically shows an example of the transfer timing and structure of the print data SI in the modification. The pattern data SP shown in FIG. 13 is bit data indicating whether or not the ejection waveforms P21, P22, and P23 are supplied to the drive element 51. When the multi-value data of N pixels is “00”, no ejection waveform is supplied to the drive element 51, and no dots are formed in the pixels N1 and N2. When the multi-value data of the N pixel is “0M”, only the ejection waveform P23 is supplied to the drive element 51, and a medium dot is formed in the pixel N2. When the multi-value data of N pixels is “M0”, only the ejection waveform P21 is supplied to the drive element 51, and a medium dot is formed in the pixel N1. When the multi-value data of N pixels is “MM”, ejection waveforms P21 and P23 are supplied to the drive element 51, and medium dots are formed in the pixels N1 and N2. When the multi-value data of the N pixel is “L0”, the ejection waveforms P21 and P22 are supplied to the drive element 51, and a large dot is formed in the pixel N1. When the multi-value data of N pixels is “LM”, ejection waveforms P21, P22, and P23 are supplied to the drive element 51, a large dot is formed in the pixel N1, and a medium dot is formed in the pixel N2. Of course, the structure of the pattern data SP is not limited to the example shown in FIG.

  Large dots are formed when the multi-value data of N pixels is “L0” or “LM”. In this case, it can be seen that the maximum number of times that the ink droplet 67 is ejected from the complementary nozzle RN to the N pixels of the complementary raster RA2 is M = 3. On the other hand, when a large dot is not formed, it is understood that the maximum number of times that the ink droplet 67 is ejected from the nozzle 64 to the N pixels of the normal raster RA3 or the complementary raster RA2 is N = 2.

  As described above, in this modified example, the N discharge waveforms P1 included in the M discharge waveforms P2 of the complementary drive signal COM R are changed to the discharge waveforms supplied to the drive element 51 of the normal nozzle NN. The circuit for generating the drive signal can be simplified.

The present technology is not limited to N = 2 and M = 3, and may be N = 3 and M = 4.
FIG. 14 schematically shows an example of the relationship among the drive signal COM, the latch signal LAT, the channel signal CH, and the print timing signal PTS in the modification. The printing control unit U1 of the present modification example, when ejecting ink droplets 67 from the nozzle 64 to N = 3 pixels at the maximum N = 3 times, ejects waveforms P1a at the maximum N = 3 times during the period TA of N = 3 pixels, P1b and P1c are supplied to the drive element 51 of the nozzle 64 including at least the normal nozzle NN. The ink droplets 67 ejected by the ejection waveform P1a land on the pixel N1 and become medium dots (normal dots DT1), and the ink droplets 67 ejected by the ejection waveform P1b land on the pixel N2 and become medium dots (normal dots DT1). Thus, the ink droplet 67 ejected by the ejection waveform P1c lands on the pixel N3 and becomes a medium dot (normal dot DT1).

Further, in the case where the print control unit U1 of the present modification causes the ink droplets 67 to be ejected from the complementary nozzle RN to the N = 3 pixels at the maximum M = 4 times, the ejection is performed at the maximum M = 4 times during the period TA of N = 3 pixels. The waveforms P2a, P2b, P2c, and P2d are supplied to the drive element 51 of the complementary nozzle RN. In the print data, the ink droplets 67 ejected by the ejection waveforms P2a and P2b both land on the pixel N1 and become large dots (complementary dots DT3), and the ink droplet 67 ejected by the ejection waveform P2c land on the pixel N2. The ink droplet 67 ejected by the ejection waveform P2d is landed on the pixel N3 and becomes a middle dot.
The first drive signal COM1 and the second drive signal COM2 may be virtual drive signals or drive signals that are actually generated.

In the present modification, it is not necessary to set the maximum number of times that the ink droplet 67 is ejected from the complementary nozzle RN to N = 3 pixels of the complementary raster RA2 in order to form complementary dots, so that 2 × N = 6 times. When calculated, the printing time can be reduced to 4/6. Therefore, this modification can also speed up printing that complements the dots to be formed by the defective nozzle.
Note that N = 3 and M = 5 are also included in the present technology.

(4) Conclusion:
As described above, according to the present invention, according to various aspects, it is possible to provide a technique capable of speeding up printing that complements dots to be formed by defective nozzles. Needless to say, the above-described basic actions and effects can be obtained even with a technique that does not have the constituent requirements according to the dependent claims but includes only the constituent requirements according to the independent claims.
In addition, the configurations disclosed in the embodiments and modifications described above are mutually replaced, the combinations are changed, the known technology, and the configurations disclosed in the embodiments and modifications described above are mutually connected. It is possible to implement a configuration in which replacement or combination is changed. The present invention includes these configurations and the like.

DESCRIPTION OF SYMBOLS 1 ... Printing apparatus (printing part), 2 ... Main body, 3 ... Head unit, 41 ... Paper feed mechanism, 42 ... Encoder, 46 ... Control part, 47 ... Oscillation circuit, 48 ... Drive signal generation circuit, 51 ... Drive element, 52 ... Drive circuit, 54 ... Shift register, 55 ... Latch circuit, 56 ... Decoder, 57 ... Control logic, 58 ... Level shifter, 59 ... Switch circuit, 64 ... Nozzle, 67 ... Ink droplet (droplet), 68 ... Nozzle Column 70 ... detection unit 100 ... head CH channel signal CK clock signal COM, COM1, COM2 drive signal COM A first partial drive signal COM B second partial drive signal COM R Complementary drive signal, D1 ... arrangement direction, D2 ... relative movement direction, D3 ... width direction, DA1 ... print data, DA11 ... original data, DA12 ... complementary data DT ... dot, DT1 ... normal dot, DT2, DT3 ... complementary dot, LAT ... latch signal, LN ... defective nozzle, NN ... normal nozzle, RN ... complementary nozzle, M1 ... printed material, N1, N2, PX, PXL ... pixel , P0, P1, P2, P11, P21 to P23 ... discharge waveform, PTS ... print timing signal, R1 ... unit of N pixels, RA1, RA2, RA2a to RA2d, RA3 ... raster, SI ... print data, SP ... pattern data , TA ... N pixel period, U0 ... print control device, U1 ... print control unit, U2 ... drive signal generation unit, U20 ... partial drive signal generation unit, U3 ... defective nozzle detection unit.

Claims (9)

A printing control device for a printing unit in which a plurality of nozzles that discharge droplets forming dots and a printing material are relatively moved in a relative movement direction,
The plurality of nozzles includes a complementary nozzle that forms complementary dots on the second raster to complement the dots of the first raster to be recorded by the defective nozzle,
In the second raster, discharge of droplets from the complementary nozzle is controlled in units of N pixels (N is an integer of 2 or more) continuous in the relative movement direction, and the N pixel of the second raster is supplemented with the complementary pixel. A printing control apparatus comprising a printing control unit that sets the maximum number of times droplets are ejected from a nozzle to M times (M is an integer larger than N and smaller than 2N).   The print control unit sets the maximum number of times that a droplet is ejected from the normal nozzle to N pixels in a raster recorded by a normal nozzle excluding the complementary nozzle among the plurality of nozzles. The printing control apparatus according to 1.   The print control unit discharges a droplet from the complementary nozzle to the N pixel of the second raster when forming the complementary dot by overlapping the droplet on the pixel included in the N pixel of the second raster. The printing control apparatus according to claim 1, wherein the number of times is set to the M times. The print control unit includes a drive signal generation unit that generates a drive signal having a discharge waveform indicating a timing at which droplets are discharged from the nozzle to the drive element.
In the drive signal, the timing at which the ejection waveform appears is repeated in units of the N pixels,
4. The print control unit according to claim 1, wherein the maximum number of times that the ejection waveform is supplied to the complementary nozzle drive element during the N pixel period is set to the M times. 5. The printing control apparatus according to item.   The print control unit is configured to supply a maximum of the discharge waveform during a period of N pixels of a raster recorded by the normal nozzle to a drive element of a normal nozzle excluding the complementary nozzle among the plurality of nozzles. The printing control apparatus according to claim 4, wherein the number of times is N. The drive signal generation unit includes a discharge waveform representing a timing at which the N droplets are discharged from the normal nozzle during the N pixel period, and the M liquid from the complementary nozzle during the N pixel period. A partial drive signal generation unit that generates a first partial drive signal having a part and a second partial drive signal having a remaining part of a combined discharge waveform representing a discharge timing of a droplet; ,
The printing control unit determines the maximum number of N or M discharge waveforms during the N pixel period based on at least one of the first partial drive signal and the second partial drive signal. The print control apparatus according to claim 5, wherein the print control apparatus supplies the drive element. The drive signal generation unit generates a complementary drive signal having a discharge waveform representing a timing at which the M droplets are discharged from the complementary nozzle during the N pixel period,
The print control according to claim 5, wherein the print control unit sets the N discharge waveforms included in the M discharge waveforms of the complementary drive signal to a discharge waveform that is supplied to the drive element of the normal nozzle. apparatus.   The N discharge waveforms included in the M discharge waveforms of the complementary drive signal include a first speed discharge waveform and a second speed discharge waveform in which droplet discharge speeds from the normal nozzle are different from each other. The print control apparatus according to claim 7, further comprising: A printing control method for a printing unit in which a plurality of nozzles that discharge droplets that form dots and a substrate are relatively moved in a relative movement direction,
The plurality of nozzles includes a complementary nozzle that forms complementary dots on the second raster to complement the dots of the first raster to be recorded by the defective nozzle,
In the second raster, discharge of droplets from the complementary nozzle is controlled in units of N pixels (N is an integer of 2 or more) continuous in the relative movement direction, and the N pixel of the second raster is supplemented with the complementary pixel. A printing control method in which the maximum number of times droplets are ejected from a nozzle is set to M times (M is an integer larger than N and smaller than 2N).

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