JP2016172394A - Liquid ejection apparatus and liquid ejection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid ejection device and a liquid ejection method capable of suppressing the quality degradation of an object formed by ejection of liquid.SOLUTION: A liquid ejection device comprises: a data output control unit for outputting control data SI, selection data SPr, and second data matching first data before a drive signal generation unit outputs a drive signal COM, wherein the first data is at least one of the control data SI and the selection data SPr; an error check unit for determining whether or not the first data matches the second data in the data input from the data output control unit; and an ejection control unit which, if the determination result is yes, controls the application and non-application of a waveform to a drive element 62 on the basis of the control data SI and selection data SPr; if the determination result is no, controls the application and non-application of a waveform to the drive element 62 on the basis of the control data SI and non-ejection selection data SPx which indicates non-ejection of a liquid by application or non-application of each waveform.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a liquid discharge apparatus and a liquid discharge method for discharging a liquid.

  An ink jet printing apparatus, which is an example of the liquid ejection apparatus described above, includes, for example, a controller provided in a printing apparatus main body and a print head that ejects liquid such as ink, as disclosed in Patent Document 1. And a head unit. Various data and signals output from the controller are input to the head unit through a flexible cable. The signal output from the controller is, for example, a drive signal that drives a plurality of ejection units. The data output by the controller is, for example, print data for controlling application and non-application of the drive signal to each ejection unit, and selection that specifies which drive pulse is selected from among a plurality of drive pulses included in the drive signal. It is data.

  By the way, in the printing apparatus, as the medium to be printed becomes larger, the distance that the head unit is scanned becomes longer. As a result, various disturbances caused by the head unit being scanned over a long distance are generated for various processes. As a technique for suppressing the influence of such disturbance, for example, as described in Patent Document 2, a technique is known in which a disturbance with respect to the movement of the carriage is estimated and the estimation result is fed back to the driving amount of the carriage motor.

JP 2007-112149 A JP 2007-283561 A

  On the other hand, the longer the distance that the head unit is scanned, the longer the wiring for transferring data to the head unit. When such a wiring length becomes long, the transfer of data from the controller to the head unit is likely to be affected by disturbance. In particular, in recent years, for the purpose of increasing the processing speed of the printing apparatus, for example, it is required to shorten the period from the start of printing to the time when ink is ejected and printing is actually started. Within such a period, the period in which the motor for transporting the medium and the motor for scanning the carriage start to be driven overlaps the period in which various data are transferred from the controller to the head unit. Since a lot of noise is generated during the period when the motor is started, when various data is transferred during such a period, the logical value of the data is inverted or the data is shifted such that the bit position of the data is shifted. Error is likely to occur.

  Such a data transfer error is an obstacle to improving the quality of the printing result by causing erroneous ejection in which ink is not ejected from nozzles that should eject ink or ink is ejected from nozzles that should not eject ink. It has become. Note that the controller and head unit of the main body communicate with each other through a transmission line such as a flexible cable, and the motor drive period before starting the liquid discharge is not limited to the ink jet printing apparatus. In the configuration in which data is transferred, there are generally similar problems.

  An object of the present invention is to provide a liquid ejecting apparatus and a liquid ejecting method capable of suppressing deterioration in quality of a target formed by ejecting liquid.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
A liquid ejection apparatus that solves the above problems includes a plurality of drive elements for ejecting liquid, a drive signal generation unit that generates a drive signal including a plurality of waveforms for driving the drive elements, and driving of the drive elements. The control data for determining the size of the liquid dot to be formed for each of the drive elements, and selection data for associating the size of the dot with the applicability of each waveform, and generating the control data and the selection At least one of the data is first data, a data generation unit that generates second data that matches the first data, and before the drive signal generation unit outputs the drive signal, the data generation unit Among the data input control unit that outputs the generated control data, the selection data, and the second data, and the data input from the data output control unit An error check unit that determines whether or not the first data and the second data match; a storage unit that stores non-ejection selection data that indicates whether or not the liquid is non-ejected by application of each waveform; When the result of the determination is coincident, application and non-application of the waveform to the drive element are controlled based on the control data and the selection data input from the data output control unit, and the result of the determination is A discharge control unit that controls application and non-application of the waveform to the drive element based on the control data and the non-discharge selection data input from the data output control unit when they do not match; The head unit having the error check unit, the storage unit, and the ejection control unit, the drive signal generation unit, the data generation unit, and the data output control unit A control unit having the control data, the selection data, and a transmission path of the second data, and a flexible cable for electrically connecting the head unit and the control unit.

  According to the above configuration, data is transferred twice from the control unit to the head unit before the drive signal generation unit outputs the drive signal. When these data do not match, that is, when a transfer error occurs in the data, ejection control based on the non-ejection selection data is performed, and no liquid is ejected. Accordingly, the liquid is not ejected based on erroneous data. Compared to the case where the liquid is not ejected to a position where the liquid should not be ejected, the fact that the liquid is not ejected has a smaller influence on the quality of the object formed by the liquid ejection. Therefore, it is possible to suppress the deterioration of the quality of the object formed by the liquid discharge.

  In the liquid ejection apparatus, the error check unit outputs an error signal indicating the mismatch to the control unit when the result of the determination is mismatch, and when the error signal is input to the control unit, The data output control unit preferably outputs the first data again toward the discharge control unit.

  According to the above configuration, when a transfer error occurs in the data, since the data is retransmitted, it is possible to drive the drive element based on the retransmitted data. Therefore, the quality of the target formed by the liquid ejection is improved as compared with a configuration in which no liquid is ejected to the position where the liquid was to be ejected based on the data in which the transfer error occurred.

  In the liquid ejecting apparatus, at least one of a period in which the data output control unit outputs the first data and a period in which the data output control unit outputs the second data is a medium that receives the liquid ejection. It may be included in a period during which the liquid is transported to a position where it is discharged.

  During the period in which the medium is transported to the position where the liquid is discharged, noise is particularly likely to occur due to the motor being driven to transport the medium, and data transfer errors based on noise are likely to occur. According to the above configuration, since data is transferred twice from the control unit to the head unit during a period in which such a data transfer error is likely to occur and liquid transfer error occurs, liquid is not discharged. It is possible to appropriately suppress the deterioration of the quality of the target formed by the ejection of the liquid.

  The liquid ejecting apparatus further includes a carriage mounted with the head unit and reciprocating, the data output control unit outputting the first data, and the data output control unit outputting the second data. At least one of the periods may be included in a period in which the carriage accelerates toward a position for discharging the liquid.

  During the period during which the carriage is accelerated, noise is particularly likely to occur due to the motor being driven to move the carriage, and data transfer errors based on noise are likely to occur. According to the above configuration, since data is transferred twice from the control unit to the head unit during a period in which such a data transfer error is likely to occur and liquid transfer error occurs, liquid is not discharged. It is possible to appropriately suppress the deterioration of the quality of the target formed by the ejection of the liquid.

  A liquid ejection method that solves the above problem is a liquid in which a head drive circuit controls a plurality of drive elements based on drive signals, control data, and selection data output from a control unit via a flexible cable, and ejects liquid. In the ejection method, the driving signal includes a plurality of waveforms for driving the driving elements, and the control data determines a size of a liquid dot formed by driving the driving elements for each driving element. The selection data is data for associating the size of the dots with applicability of each waveform, and before the control unit outputs the drive signal to the head drive circuit, the control data and the A first step of outputting first data including at least one of selection data and second data matching the first data; and the head driving circuit, A second step of determining whether or not the first data and the second data input from the control unit match, and the head driving circuit is configured to perform the control based on the control data and the selection data. A third step of controlling application and non-application of the waveform to the drive element, wherein data indicating non-ejection of the liquid by the applicability of each waveform is non-ejection selection data, and in the second step When it is determined that the first data does not match the second data, the non-ejection selection data is used as the selection data in the third step.

  According to the above method, data is transferred twice from the control unit to the head drive circuit before the control unit outputs the drive signal. When these data do not match, that is, when a transfer error occurs in the data, ejection control based on the non-ejection selection data is performed, and no liquid is ejected. Accordingly, the liquid is not ejected based on erroneous data. Compared to the case where the liquid is not ejected to a position where the liquid should not be ejected, the fact that the liquid is not ejected has a smaller influence on the quality of the object formed by the liquid ejection. Therefore, it is possible to suppress the deterioration of the quality of the object formed by the liquid discharge.

FIG. 3 is a perspective view illustrating an overview configuration of a printer that is the first embodiment of the liquid ejection apparatus. The block diagram which shows the connection form of a head unit and a circuit board. FIG. 6 is a plan view showing the relationship between the arrangement of nozzles and drive elements in the ejection head. The data block diagram which shows the data structure of printing control data. 6 is a timing chart showing transitions of various signal outputs and transitions of print control data transfer. FIG. 3 is a block diagram illustrating an electrical configuration of the printer. FIG. 2 is a block diagram showing a part of an electrical configuration of a discharge control system in a head drive circuit. A truth table showing correspondence between print data and pulse selection information. FIG. 3 is a block diagram illustrating an electrical configuration of an erroneous ejection determination system and an ejection control system in a head drive circuit. 6 is a timing chart showing changes in the output of various signals during print control data comparison determination processing. The flowchart which shows the signal output sequence in a controller. 6 is a flowchart showing a signal input sequence in the head drive circuit. FIG. 5 is a block diagram illustrating an electrical configuration of a printer that is a second embodiment of a liquid ejection apparatus. The flowchart which shows the signal output sequence in a controller. 6 is a flowchart showing a signal input sequence in the head drive circuit. 6 is a timing chart showing changes in the output of various signals during print control data comparison determination processing.

(First embodiment)
Hereinafter, a first embodiment embodying a liquid ejection apparatus and a liquid ejection method will be described with reference to the drawings.

  A printer 11 that is an example of the liquid ejection apparatus illustrated in FIG. 1 is, for example, an ink jet printer. The printer 11 includes a bottomed box-shaped frame 12 that is partially open including the upper part, and a support base 13 that supports paper P, which is an example of a medium, is disposed at the bottom of the frame 12. A guide member 14 extending in parallel with the longitudinal direction of the support base 13 is installed above the support base 13 with both ends supported by the frame 12. The carriage 15 is supported by the guide member 14 so as to be capable of reciprocating in the scanning direction X. The discharge head 16 is supported by the carriage 15 so as to face the support base 13. A liquid container 17 containing ink, which is an example of a liquid, is detachably attached to the carriage 15.

  Note that the number of the liquid containers 17 in the present embodiment is four, and each of the four liquid containers 17 stores inks of different colors. As an example of the ink, black (K), cyan ( C), magenta (M) and yellow (Y) inks are separately stored in these liquid containers 17. The ink supplied from each liquid container 17 is discharged toward the paper P from the discharge head 16 moving in the scanning direction X together with the carriage 15. As a result, a color image or character is printed on the paper P.

  In the scanning direction X, a driving pulley 18 is disposed at one of both ends of the frame 12, and a driven pulley 19 is disposed at the other of the both ends. The driving pulley 18 and the driven pulley 19 are supported by the frame 12 in a rotatable state. An output shaft of a carriage motor 20 that is a power source of the carriage 15 is connected to the drive pulley 18. An endless timing belt 21 is hung on the pair of pulleys 18 and 19. When the driving force of the carriage motor 20 is transmitted to the carriage 15 through the timing belt 21, the carriage 15 guided by the guide member 14 reciprocates in the scanning direction X.

  The printer 11 is provided with a transport motor 22 and various rollers that are rotated by the driving force output by the transport motor 22. The rollers are rotated by driving the transport motor 22, and the rollers are rotated to rotate the rollers in a direction intersecting the scanning direction X, for example, a transport direction Y that is a direction orthogonal to the scanning direction X. The upper sheet P is conveyed.

  In the frame 12, a maintenance device 23 for performing maintenance of the ejection head 16 is provided in a non-printing region that is one end of the moving region of the carriage 15. The maintenance device 23 performs flushing for discharging ink from the discharge head 16 into the cap 24, cleaning for discharging ink of the ink supply system from the discharge head 16, and the like.

Next, a configuration for inputting a signal and transferring data to the head unit 60 including the ejection head 16 will be described with reference to FIG.
As shown in FIG. 2, the printer 11 includes a circuit board 30 fixed to the frame 12 and a head drive circuit 61 provided in the head unit 60. The head drive circuit 61 controls the drive of the drive element 62 provided for each nozzle. The head drive circuit 61 constitutes a head unit 60 together with the ejection head 16. The drive element 62 is, for example, a piezoelectric vibrator or an electrostatic drive element.

  The circuit board 30 is electrically connected to the head drive circuit 61 via a flexible cable 65 which is a transmission path for various data and signals. The flexible cable 65 has a length that does not hinder the movement of the carriage 15.

  The circuit board 30 includes a controller 31 that is an example of a control unit that controls driving of the printer 11. The controller 31 has a microcomputer 32 and an ASIC 33. ASIC is an abbreviation for “Application Specific IC”. The controller 31 generates various data and various signals for controlling driving of the driving element 62. Various data generated by the controller 31 is transmitted to the head drive circuit 61 through the data line DL constituting the flexible cable 65. Various signals generated by the controller 31 are output to the head drive circuit 61 through the signal lines SL for each signal constituting the flexible cable 65. The head drive circuit 61 receives various data and signals from the controller 31, and applies or does not apply a plurality of drive pulses included in the received signal for each drive element 62 based on the received various data. The selected drive pulse is input to the drive element 62. Ink is ejected from the nozzle corresponding to the drive element 62 to which the drive pulse is input, and printing of images, characters, and the like based on various data is performed on the paper P. Among the plurality of drive pulses, a drive pulse that vibrates the drive element 62 to such an extent that ink is not ejected is included. No ink is ejected from the nozzle corresponding to the drive element 62 to which such a drive pulse is applied, The ink interface in the nozzle vibrates slightly.

  The data transferred to the head drive circuit 61 includes print data SI which is an example of control data and selection data SP. The data line DL transfers these data SI and SP from the controller 31 to the head drive circuit 61. The signals input to the head drive circuit 61 include a drive signal COM, a latch signal LAT, a channel signal CH, a clock signal SCK, and a transfer switching signal SW. Details of these various data and various signals will be described later. In FIG. 2, only one data line DL is shown, but the number of data lines DL is the same as the number of ink colors, and in this embodiment, there are four. The data SI and SP for each color are serially transferred through the data line DL associated with each color, and the data SI and SP for all colors are transferred in parallel through all the data lines DL.

  Next, the discharge head 16 will be described with reference to FIG. As shown in FIG. 3, a nozzle opening surface 161 that is the bottom surface of the ejection head 16 includes a plurality of nozzles 162 that are arranged in a line at a constant nozzle pitch in the transport direction Y that is the vertical direction in the drawing. A column is formed. One nozzle row is formed for each ink, and four nozzle rows are formed on the nozzle opening surface 161 of the present embodiment. One nozzle row is composed of, for example, a total of 360 nozzles 162 indicated by # 1 to # 360. In the example of FIG. 3, four nozzle rows are provided that can eject four colors of ink of black (K), cyan (C), magenta (M), and yellow (Y), respectively. The arrangement pattern of the nozzles constituting the nozzle row is not limited to the one-row arrangement, and may be a zigzag arrangement in which the two rows of nozzles are shifted by a half pitch in the row direction. If the number of nozzles per row is plural, the number may be changed as appropriate.

  The ejection head 16 includes the same number of drive elements 62 as the nozzles 162. The drive element 62 is disposed at a position facing the nozzle 162, and the element arrangement of the drive element 62 has the same arrangement pattern as the nozzle row. In FIG. 3, for convenience of explaining the relationship between the arrangement of the nozzles 162 and the arrangement of the drive elements 62, the drive elements 62 are schematically shown outside the ejection head 16. One discharge portion 63 is configured by the nozzle 162 and the drive element 62 forming one pair. In the ejection head 16, for example, one ejection section group 64 including 360 ejection sections 63 corresponding to each of 360 nozzles 162 is provided for each nozzle row.

Next, various signals used for driving the drive element 62, that is, the drive signal COM, the latch signal LAT, and the channel signal CH will be described with reference to FIG.
As shown in FIG. 5, the controller 31 determines the printing cycle TA as a repeated period in which the drive signal COM is applied once. The printing cycle TA is a period determined by the latch signal LAT, and the controller 31 outputs the latch signal LAT once for each printing cycle TA.

  The drive signal COM is composed of drive pulses having a plurality of waveforms. The drive signal COM in the present embodiment is composed of four drive pulses for each printing cycle TA. The four drive pulses are the first drive pulse DP1, the second drive pulse DP2, the third drive pulse DP3, and the fourth drive pulse DP4. The controller 31 outputs the drive pulses in this order in time series. The first drive pulse DP1 has a large amplitude among the four drive pulses and is output during the first period T1. The second drive pulse DP2 has a small amplitude among the four drive pulses and is output in the second period T2 following the first period T1. The second drive pulse DP2 is a pulse for vibrating the drive element 62 to such an extent that ink is not ejected, and slightly vibrates the ink in the nozzle. The third drive pulse DP3 has a large amplitude among the four drive pulses, and is output in a third period T3 following the second period T2. The fourth drive pulse DP4 has a medium amplitude among the four drive pulses, and is output in a fourth period T4 following the third period.

  The latch signal LAT is a signal for determining various data received from the controller 31 by the head driving circuit 61. The latch signal LAT defines the timing when the output of the drive signal COM is started, that is, the timing when the first drive pulse DP1 is output.

  The channel signal CH defines the timing at which the four driving pulses included in the driving signal COM are switched from the previously output driving pulse to the next driving pulse output subsequent thereto. That is, the channel signal CH is output at a timing when the first driving pulse DP1 is switched to the second driving pulse DP2, is output at a timing when the second driving pulse DP2 is switched to the third driving pulse DP3, and is output from the third driving pulse DP3. It is output at the timing of switching to the 4 drive pulse DP4.

  The controller 31 generates a black print control data SIn (K), a cyan print control data SIn (C), a magenta print control data SIn (M), and a yellow print control data SIn (Y). The signal is transferred to the head drive circuit 61 through the flexible cable 65 in synchronization with the signal SCK. In the following description, when the colors are not particularly distinguished, they are simply referred to as print control data SIn.

  The print control data SIn transmitted from the controller 31 is composed of print data SI and selection data SP. The print data SI is generated for each nozzle row, and discharge or non-discharge is determined once for all the discharge units 63 included in the nozzle row. The selection data SP is data for causing the head driving circuit 61 to select a driving pulse used for driving from four driving pulses included in the driving signal COM.

  The controller 31 transfers the print control data SIn to the head drive circuit 61 in synchronization with the clock signal SCK. At this time, the controller 31 outputs the selection data SP after outputting the printing data SI, and repeats the transfer of the printing control data SIn every printing cycle TA. That is, the controller 31 synchronizes the black print data SI (K) and the black selection data SP and the cyan print data SI (C) and the cyan selection data SP with the clock signal SCK within the print cycle TA. Transfer one by one. Further, the controller 31 synchronizes the magenta print data SI (M) and the magenta selection data SP, and the yellow print data SI (Y) and the yellow selection data SP with the clock signal SCK within the print cycle TA. Transfer one by one. The print control data SIn transferred in one printing cycle TA is used for ejection control in the printing cycle TA next to the printing cycle TA.

Next, the print data SI and the selection data SP will be described with reference to FIG.
The print data SI defines ink ejection and non-ejection for each nozzle 162. Further, the print data SI of the present embodiment defines the size of the ink dots formed on the paper P by the drive of the drive element 62 as the drive mode of the drive element 62. The print data SI is, for example, four-gradation data in which 2 bits are assigned to each nozzle 162, and represents the dot size of any one of no dots, small dots, medium dots, and large dots for each nozzle 162. The print data SI includes upper bit data SIH consisting of only the upper bits of the two bits assigned to each nozzle 162, and lower bit data SIL consisting of only the lower bits of the two bits assigned to each nozzle 162. including. The number of bits included in the high-order bit data SIH is 360 bits in which 360 bits are associated with each nozzle 162 by one bit. The number of bits included in the lower-order bit data SIL is also 360 bits, in which one bit is associated with each nozzle 162 for 360 nozzles 162.

  The selection data SP is data for selecting the driving mode of each driving element 62. There are four types of drive modes of the drive element 62 in the present embodiment, and the selection data SP includes 4-bit data indicating selection of the fourth drive pulse DP4 for each drive mode. The selection data SP includes 4-bit data indicating selection of the third driving pulse DP3 for each driving mode, 4-bit data indicating selection of the second driving pulse DP2 for each driving mode, and first data for each driving mode. It includes 4-bit data indicating selection of drive pulse DP1.

  Next, the electrical configuration of the printer 11 will be described with reference to FIG. In the following, the ink ejected from each nozzle forms one dot in one printing cycle TA, and the area where each dot is formed on the paper P is one pixel. In addition, a pixel row in which dots are formed by ejection of each nozzle row in one printing cycle TA is one pixel row, and print control data SIn for forming dots in each pixel row is equivalent to one row. Print control data SIn. Further, when the carriage 15 moves once in the scanning direction X, that is, a set of pixels in which dots are formed during one main scan is performed, one pixel row, and one pixel row The print control data SIn for forming dots in the line is the print control data SIn for one line. The print control data SIn for one line includes print control data SIn for a plurality of columns.

  Each pixel row included in one sheet of paper P is referred to as a first pixel row, a second pixel row,... In the order in which dots are formed, that is, in the order in which the dots are arranged in the transport direction Y. The print control data SIn for the first pixel row is called the first print control data SIn, the print control data SIn for the second pixel row is called the second print control data SIn,. . Further, a plurality of pixel columns included in one pixel row are arranged in the order in which dots are formed, that is, in the order in which they are arranged in the scanning direction X, the first pixel column, the second pixel column,. The print control data SIn for the first pixel row is designated as the first print control data SIn, the print control data SIn for the second pixel row is designated as the second print control data SIn,. Called.

  That is, the pixel column in which dots are first formed on one sheet of paper P is the pixel column in the first row and first column. When one print job data input to the controller 31 is processed, the print control data SIn first transferred from the controller 31 to the head drive circuit 61 is the print control data SIn in the first row and the first column. Then, the print control data SIn for each pixel row and each pixel column is transferred from the controller 31 to the head drive circuit 61 in the order of the arrangement of each pixel row and each pixel column.

  As shown in FIG. 6, the controller 31 of the printer 11 includes an external interface (hereinafter also referred to as “external I / F”) 34 in addition to the microcomputer 32 (hereinafter also simply referred to as “computer 32”) and the ASIC 33. And an internal interface (hereinafter also referred to as “internal I / F”) 35. The external I / F 34 is an interface for receiving print job data (hereinafter also simply referred to as “print job”) from a host device such as a personal computer, and the internal I / F 35 communicates with the head drive circuit 61. It is an interface for doing.

  The computer 32 includes a main control unit 41 composed of a CPU, a RAM 42 that temporarily stores various data, and a nonvolatile memory 43 that stores various programs. The computer 32 is electrically connected to an operation unit 25 that is operated to give various instructions and inputs to the printer 11 and a display unit 26 including, for example, a liquid crystal display panel. The main control unit 41 performs processing for receiving an instruction, setting content, and the like based on a signal from the operation unit 25 and display processing for displaying a menu screen, various messages, and the like on the display unit 26.

The main control unit 41 controls driving of the carriage motor 20 and the transport motor 22 via the motor drive circuits 51 and 52.
Specifically, the main control unit 41 first causes the transport motor 22 to transport the paper P toward the initial position where ink is ejected by controlling the drive of the transport motor 22 via the motor drive circuit 52. The initial position is the position of the paper P in which the pixel column in the first row and first column faces the ejection head 16. When the main control unit 41 completes the control of the conveyance of the paper P to the initial position, the controller 31 starts outputting drive pulses to the drive element 62. Further, every time the carriage 15 is reciprocated in the scanning direction X, the main control unit 41 controls the driving of the transport motor 22 and transports the paper P in the transport direction Y by the length of one pixel row.

  Further, the main control unit 41 controls the driving of the carriage motor 20 via the motor driving circuit 51 to direct ink from one end in the moving region of the carriage 15 to a position where ink is ejected to the first pixel column. As a result, the carriage 15 is accelerated. When the main control unit 41 completes the control of the carriage 15 to the ink ejection position, the controller 31 starts outputting drive pulses to the drive element 62. Thereafter, the main control unit 41 moves the carriage 15 in the scanning direction X at a substantially constant speed while ink is intermittently ejected from the ejection unit 63. The main control unit 41 accelerates or decelerates the carriage 15 during a period between the ejection of ink to pixels in adjacent rows. The acceleration / deceleration of the carriage 15 may also be performed while ink is being ejected to the pixel columns included near the ends of the pixel rows.

  The ASIC 33 outputs an oscillation circuit 45 that generates a clock signal SCK, a drive signal generation circuit 46 that is an example of a drive signal generation unit that generates the drive signal COM, and data such as print data SI and selection data SP. And a data output control unit 47.

  The RAM 42 has an input buffer 42A, a work memory 42B, and an output buffer 42C. The input buffer 42A temporarily stores print data in a print job received by the external I / F 34 from the host device. The work memory 42B temporarily stores data being processed. In the output buffer 42C, which is also an image buffer, print data SI as image data for printing that is serially transferred to the head drive circuit 61 is developed.

  The main control unit 41 includes a discharge control signal generation unit 411. The ejection control signal generation unit 411 reads out and analyzes the print data in the input buffer 42A, and develops it into multi-bit print data SI with reference to font data, a graphic function, etc. in the nonvolatile memory 43. The developed print data SI is stored in the output buffer 42C. When print data SI corresponding to one main scan of the ejection head 16, that is, one line of print data SI is obtained, this one line worth of print data SI is obtained. The print data SI is output to the data output control unit 47. In the present embodiment, the discharge control signal generation unit 411 corresponds to an example of a data generation unit.

  The main control unit 41 instructs the drive signal generation circuit 46 to output the drive signal COM, the latch signal LAT, and the channel signal CH to the head drive circuit 61. The drive signal generation circuit 46 generates a drive signal COM, a latch signal LAT, and a channel signal CH based on an instruction from the main control unit 41, and outputs the signals COM, LAT, and CH to the head drive circuit through the internal I / F 35. Input to 61. That is, the drive signal generation circuit 46 repeats the drive signal COM in which the first drive pulse DP1, the second drive pulse DP2, the third drive pulse DP3, and the fourth drive pulse DP4 are arranged in time series in units of the printing cycle TA. Generate. The drive signal generation circuit 46 synchronizes the timing when the output of the drive signal COM is started and the timing when the output of the latch signal LAT is started. The drive signal generation circuit 46 synchronizes the timing at which the previous drive pulse is switched to the next drive pulse in the drive signal COM and the timing at which the channel signal CH is output. These signals COM, LAT, and CH are input from the internal I / F 35 to the head drive circuit 61 via the flexible cable 65. Further, the drive signal generation circuit 46 inputs a data trigger DT for starting transfer of various data to the data output control unit 47.

  The main control unit 41 instructs the data output control unit 47 to transfer the print control data SIn. The data output control unit 47 obtains permission from the main control unit 41 to directly access the RAM 42. Further, the data output control unit 47 obtains permission from the main control unit 41 to directly access the nonvolatile memory 43 and reads the selection data SP from the nonvolatile memory 43. The data output control unit 47 transmits the print data SI read from the output buffer 42C and the selection data SP read from the nonvolatile memory 43 in synchronization with the clock signal SCK from the oscillation circuit 45.

  Specifically, the data output control unit 47 serially transfers the print data SI to the head drive circuit 61 through the flexible cable 65 by one nozzle row, that is, one pixel row. Further, when the data trigger DT is input from the drive signal generation circuit 46, the data output control unit 47 serially transfers the selection data SP to the head drive circuit 61 following the transfer of the print data SI for each pixel column. .

  For example, a logical array corresponding to the print mode is set in the selection data SP, and the selection data SP corresponding to the print mode specified in the print job is output. Note that the printer 11 of the present embodiment includes, for example, a high-quality print mode such as a photo print mode that gives priority to print quality over the print speed, and a high-speed print mode such as draft print mode that gives priority to print speed over print quality. A plurality of printing modes including are prepared. The nonvolatile memory 43 stores a plurality of selection data SP for each print mode. The controller 31 reads one selection data SP corresponding to the designated print mode from the nonvolatile memory 43 at the start of printing, and the read selection data SP is output to the head after the print data SI every time the print data SI is output. Output to the drive circuit 61. In the case of flushing for ejecting ink that is not related to printing, if a driving pulse dedicated for maintenance that is different from the driving pulse at the time of printing is used, the selection data SP for flushing is output at the start of flushing and the flushing is completed. Later, selection data SP before flushing is output.

  Here, in this embodiment, the data output control unit 47 prints data SI and selection data SP in the first row and first column, that is, print control data that is first transferred when processing a print job for one sheet P. SIn is output twice to the head drive circuit 61. All of these data are transferred to the head drive circuit 61 before the drive signal generation circuit 46 outputs the drive signal COM, that is, before the start of the printing cycle TA. In other words, the print control data SIn in the first row and the first column is transferred to the head drive circuit twice before the ejection of ink from the ejection unit 63 is started.

  The two data to be transmitted are data having the same logical arrangement, and hereinafter, the print control data SIn in the first row and the first column output by the data output control unit 47 for the first time is referred to as first print control data SIn1. The print control data SIn in the first row and the first column output by the data output control unit 47 for the second time is referred to as second print control data SIn2.

  The data output control unit 47 outputs the transfer switching signal SW to the head drive circuit 61 through the flexible cable 65 until the output of the second print control data SIn2 is started after the first print control data SIn1 is output. To do. The transfer switching signal SW is a signal indicating switching between the transfer period of the first print control data SIn1 and the transfer period of the second print control data SIn2.

  As shown in FIG. 6, one head driving circuit 61 is provided for each type of ink, that is, for each nozzle row. Each head drive circuit 61 includes a control circuit 70, a reception unit 71, an SP storage unit 72, an error check unit 74, and a discharge control unit 75.

  The SP storage unit 72 stores non-print selection data SPx, which is an example of non-ejection selection data. The non-print selection data SPx includes only the second drive pulse DP2 of the drive signal COM as a pulse to be supplied to the drive element 62, that is, from the nozzle, regardless of the gradation information indicated by the print data SI. This is selection data SP for selecting only pulses for causing the ink in the nozzle to vibrate without ejecting ink. Hereinafter, the selection data SP included in the print control data SIn transmitted from the controller 31 to the head drive circuit 61 is referred to as transfer selection data SPr.

  The receiving unit 71 sequentially inputs print control data SIn for one column from the data output control unit 47 in synchronization with the clock signal SCK. The receiving unit 71 has a selector function for switching the input destination of the printing control data SIn. When inputting the printing control data SIn in the first row and the first column, the receiving unit 71 inputs the first printing control data SIn1 to the error checking unit 74, 2 The print control data SIn2 is input to the ejection control unit 75. The receiving unit 71 inputs the printing control data SIn to the ejection control unit 75 when inputting the printing control data SIn for the first row and the second column.

  The control circuit 70 outputs a signal for controlling the operation of each unit included in the head drive circuit 61. Specifically, the control circuit 70 outputs the selection signal SEL1 for controlling the input of the print control data SIn to the verification data storage unit 741 provided in the error check unit 74, and the discharge data provided in the discharge control unit 75. A selection signal SEL2 for controlling the input of the print control data SIn to the storage unit 751 is output.

  At the start of print job processing, that is, at the start of transfer of the print control data SIn in the first row and first column, the control circuit 70 selects a selection signal SEL1 for controlling the input destination of the print control data SIn to the verification data storage unit 741. , SEL2 are output. Then, the control circuit 70 outputs selection signals SEL1 and SEL2 for controlling the input destination of the print control data SIn to the ejection data storage unit 751 at the timing specified by the transfer switching signal SW.

  The error check unit 74 includes the verification data storage unit 741, the comparison circuit 742, and the determination circuit 743. The error check unit 74 performs an error check on the print control data SIn in the first row and the first column input from the controller 31 to the head drive circuit 61. Specifically, the error check unit 74 compares the first print control data SIn1 and the second print control data SIn2, and the input print control data SIn in the first row and first column is correct. That is, whether or not a transfer error such as inversion of the logical value or data shift has occurred in the input print control data SIn in the first row and first column is verified.

  The verification data storage unit 741 receives the selection signal SEL 1 from the control circuit 70 and the latch signal LAT from the controller 31. When the control circuit 70 inputs the selection signal SEL1 to the verification data storage unit 741, the verification data storage unit 741 inputs the first print control data SIn1 and uses the input first print control data SIn1 as the latch signal LAT. To confirm.

  The comparison circuit 742 compares the first print control data SIn1 input from the verification data storage unit 741 with the second print control data SIn2 input from the ejection data storage unit 751, and sends the comparison result to the determination circuit 743. Output.

  The determination circuit 743 outputs a determination signal JS indicating whether or not the first print control data SIn1 and the second print control data SIn2 match based on the comparison result input from the comparison circuit 742. The discharge control unit 75 includes a selection information generation unit 752, and the determination signal JS sets the selection data SP input to the selection information generation unit 752 to either the transfer selection data SPr or the non-print selection data SPx. . For example, when the determination signal JS indicates coincidence of these data, the selection information generation unit 752 receives the transfer selection data SPr included in the second print control data SIn2 stored in the ejection data storage unit 751. . On the other hand, when the determination signal JS indicates data mismatch, the non-print selection data SPx output from the SP storage unit 72 is input to the selection information generation unit 752.

  Here, the control circuit 70 outputs a determination control signal CNT that is valid for a predetermined period based on the input of the transfer switching signal SW. The control circuit 70 refers to the result of timing such as a timer included in the control circuit 70, switches the determination control signal CNT from invalid to valid after a predetermined time has elapsed from the input of the transfer switching signal SW, and further determines the predetermined time. Switch from enabled to disabled after a lapse. For example, the determination control signal CNT becomes invalid before the print control data SIn in the first row and the second column is input to the selection information generation unit 752 and the gate driver circuit 753 of the ejection control unit 75.

  During the period in which the determination control signal CNT is valid, the selection data SP corresponding to the determination result indicated by the determination signal JS is input to the selection information generation unit 752 as described above. During the period when the determination control signal CNT is invalid, the selection information generation unit 752 receives transfer selection data SPr included in the second print control data SIn2 stored in the ejection data storage unit 751.

  The ejection control unit 75 includes the ejection data storage unit 751, the selection information generation unit 752, and the gate driver circuit 753. The ejection data storage unit 751 includes a print data storage unit 754 that stores print data SI of the print control data SIn.

  The ejection data storage unit 751 receives a selection signal SEL2 from the control circuit 70 and a latch signal LAT from the controller 31. When the control circuit 70 inputs the selection signal SEL2 to the discharge data storage unit 751, the discharge data storage unit 751 inputs the second print control data SIn2, and the input second print control data SIn2 is the latch signal LAT. To confirm. Then, the print data storage unit 754 outputs the latched print data SI to the gate driver circuit 753.

  The selection information generator 752 receives the transfer selection data SPr or the non-print selection data SPx, and also receives the latch signal LAT and the channel signal CH from the controller 31. The selection information generation unit 752 generates decode data based on the input selection data SP, latch signal LAT, and channel signal CH. The decoded data is data for causing the gate driver circuit 753 to generate the pulse selection information PS. The pulse selection information PS is, for example, a 4-bit logical array that selects at least one of the four drive pulses. The pulse selection information PS associates a drive pulse or a combination of drive pulses with each dot size assigned to each nozzle 162 in the print data SI. That is, in the print data SI, any one of the dot sizes of no dots, small dots, medium dots, and large dots is associated with each nozzle 162, and the pulse selection information PS includes a drive pulse and a drive for each dot size. Correlate combinations of pulses.

  The gate driver circuit 753 receives print data SI from the print data storage unit 754, decode data from the selection information generation unit 752, and drive signal COM from the controller 31. The gate driver circuit 753 drives the drive element 62 based on these various data and various signals. Specifically, the gate driver circuit 753 specifies the dot size selected by the print data SI for each drive element 62, selects the drive pulse associated with the dot size by the pulse selection information PS, and selects the selected drive pulse. A drive pulse is applied to the drive element 62.

  Next, an example of a specific configuration of the print data storage unit 754, the selection information generation unit 752, and the gate driver circuit 753 of the ejection control unit 75 will be described with reference to FIG. In FIG. 7, only the configuration provided corresponding to each of the two nozzle drive elements 62A and 62B constituting one nozzle row is shown. Further, in FIG. 7, for convenience of describing the configuration of the discharge control unit 75, the configuration related to the connection between the discharge control unit 75 and the error check unit 74 is omitted.

  As shown in FIG. 7, the print data storage unit 754 includes a print data storage unit 754A corresponding to the drive element 62A and a print data storage unit 754B corresponding to the drive element 62B. Each of the print data storage units 754A and 754B includes a first shift register 81, a second shift register 82, a first latch circuit 83, and a second latch circuit, one for each drive element 62. 84. Further, the ejection data storage unit 751 has a third shift register 85.

  In the print data storage unit 754A, the first shift register 81 holds the upper bit data SIH of the print data SI, and the second shift register 82 holds the lower bit data SIL of the print data SI. Similarly, in the print data storage unit 754B, the first shift register 81 holds the upper bit data SIH of the print data SI, and the second shift register 82 holds the lower bit data SIL of the print data SI. To do. The third shift register 85 holds transfer selection data SPr.

  The input terminal of the first latch circuit 83 is electrically connected to the output terminal of the first shift register 81. The input terminal of the second latch circuit 84 is electrically connected to the output terminal of the second shift register 82. When the latch signal LAT is input to each of the latch circuits 83 and 84, the first latch circuit 83 latches the upper bit data SIH held by the first shift register 81. The second latch circuit 84 latches the lower bit data SIL held by the second shift register 82. The output terminal of the first latch circuit 83 and the output terminal of the second latch circuit 84 are connected to the comparison circuit 742 and the gate driver circuit 753. The output terminal of the third shift register 85 is connected to the comparison circuit 742 and the selection information generation unit 752.

  The selection information generation unit 752 includes a logic circuit 86. The selection data SP is input to the logic circuit 86, and the latch signal LAT and the channel signal CH are input from the controller 31. The logic circuit 86 generates decode data used by the decoder 87 for the decoding process from the selection data SP, and outputs the decode data to each decoder 87 at a timing based on the latch signal LAT and the channel signal CH.

  The gate driver circuit 753 includes a gate driver circuit 753A corresponding to the drive element 62A and a gate driver circuit 753B corresponding to the drive element 62B. Each of the gate driver circuits 753A and 753B includes a decoder 87, a level shifter 88, and a switch circuit 89. The output terminal of the first latch circuit 83 is electrically connected to the input terminal of the decoder 87, and the upper bit data SIH latched by the first latch circuit 83 is input from the first latch circuit 83 to the decoder 87. Is done. The input terminal of the decoder 87 is electrically connected to the output terminal of the second latch circuit 84, and the lower bit data SIL latched by the second latch circuit 84 is input from the second latch circuit 84 to the decoder 87. Is done. The output terminal of the logic circuit 86 is connected to the input terminal of the decoder 87, and the decoded data output from the logic circuit 86 is input from the logic circuit 86 to the decoder 87. The decoder 87 generates pulse selection information PS based on the various types of input data, and outputs the pulse selection information PS to the level shifter 88.

  The level shifter 88 is supplied with the pulse selection information PS from the decoder 87 in order from the higher-order bit data in the pulse selection information PS for each input of the latch signal LAT and the channel signal CH. For example, the logical value of the most significant bit in the logic array of the pulse selection information PS is input at the start of the period T1 that is the first timing, and the pulse selection information PS is input at the start of the period T2 that is the second timing. The logical value of the second bit is input. The level shifter 88 functions as a voltage amplifier. When the logical value of the pulse selection information PS input this time is “1”, the level shifter 88 outputs an ON signal boosted to a voltage that can drive the switch circuit 89, for example, a voltage of about several tens of volts. Further, the level shifter 88 outputs an off signal that does not drive the switch circuit 89 when the logical value of the pulse selection information PS input this time is “0”. The on signal and the off signal generated by the level shifter 88 are input from the level shifter 88 to the switch circuit 89. For example, when the logical value of the most significant bit in the logic array of the pulse selection information PS is “1” at the start of the period T 1, the level shifter 88 inputs an ON signal to the switch circuit 89. Next, when the logical value of the second bit in the pulse selection information PS is “0” at the start of the period T 2, the level shifter 88 inputs an OFF signal to the switch circuit 89.

  A drive signal COM is input from the controller 31 to the input terminal of the switch circuit 89. The drive element 62A or the drive element 62B is connected to the output terminal of the switch circuit 89. An output terminal of the level shifter 88 is connected to the control terminal of the switch circuit 89, and an ON signal and an OFF signal are input from the level shifter 88. When an ON signal is input to the switch circuit 89, any one of the first to fourth drive pulses DP1 to DP4 is applied to each of the drive elements 62A and 62B. For example, when the logical value of the pulse selection information PS input this time to the level shifter 88 is “1”, the switch circuit 89 transitions to the ON state, and the drive pulse at that time is applied to the drive elements 62A and 62B. . On the other hand, when the logical value of the pulse selection information PS input this time to the level shifter 88 is “0”, the switch circuit 89 transits to the OFF state, and the drive pulse at that time is not applied to the drive elements 62A and 62B.

  Next, the relationship between the print data SI and the pulse selection information PS will be described with reference to FIG. FIG. 8 shows the pulse selection generated when the print data SI for each nozzle ([00], [01], [10], [11]) and the transfer selection data SPr are input to the selection information generation unit 752. It is a truth table showing a correspondence relation with information PS ([0100], [0010], [1001], [1010]).

  As shown in FIG. 8, the decoder 87 uses the 2-bit print data SI for each drive element 62 and the decode data to select four types of pulses that are 4-bit data (D1, D2, D3, D4). Information PS is generated. Data D1 indicates whether to select the first drive pulse DP1. Data D2 indicates whether or not to select the second drive pulse DP2. Data D3 indicates whether to select the third drive pulse DP3. Data D4 indicates whether to select the fourth drive pulse DP4. The 4-bit pulse selection information PS is input to the switch circuit 89 connected to each drive element 62.

  The logical arrangement of the data D4 in each pulse selection information PS is [0100] in order from the bottom of the truth table, and is the same as the logical arrangement of the transfer selection data SPr associated with the fourth drive pulse DP4 (see FIG. 4). It is. The logical arrangement of the data D3 in each pulse selection information PS is [1010] in order from the bottom of the truth table, and is the same as the logical arrangement of the transfer selection data SPr associated with the third drive pulse DP3 (see FIG. 4). It is. The logical arrangement of the data D2 in each pulse selection information PS is [0001] from the bottom of the truth table, and is the same as the logical arrangement of the transfer selection data SPr associated with the second drive pulse DP2 (see FIG. 4). It is. The logical arrangement of the data D1 in each pulse selection information PS is [1100] in order from the bottom of the truth table, and is the same as the logical arrangement of the transfer selection data SPr associated with the first drive pulse DP1 (see FIG. 4). It is.

  That is, in the processing performed by the logic circuit 86 and the decoder 87, the selection data SP, which is 16-bit serial data, is converted into 4-bit parallel data for each drive pulse. For example, the logical array [1010], which is the arrangement of the most significant bits in the parallel data for each drive pulse, is associated with the print data SI of [11]. Further, for example, the logical arrangement of the least significant bits in the parallel data for each drive pulse is associated with the print data SI of [00].

  Specifically, when the logical arrangement in the print data SI for each nozzle is [00], [0100] is generated as the pulse selection information PS. Then, the second drive pulse DP2 is applied in the second period T2 in the current printing cycle TA, and no drive pulse is applied except in the second period T2. As a result, in the current printing cycle TA, the ink is not ejected, and the ink in the nozzle is slightly vibrated to suppress the increase in the viscosity of the ink.

  When the logical arrangement in the print data SI for each nozzle is [01], [0010] is generated as the pulse selection information PS. Then, in the current printing cycle TA, the third drive pulse DP3 is applied in the third period T3, and no drive pulse is applied except in the third period T3. As a result, in the current printing cycle TA, one large ink droplet is ejected and a small dot is formed on the paper P.

  When the logical arrangement in the print data SI for each nozzle is [10], [1001] is generated as the pulse selection information PS. Then, in the current printing cycle TA, the first drive pulse DP1 is applied in the first period T1, and further, the fourth drive pulse DP4 is applied in the fourth period T4. As a result, in the current printing cycle TA, one large ink droplet and one small ink droplet are ejected, and medium dots are formed on the paper P.

  When the logical arrangement in the print data SI for each nozzle is [11], [1010] is generated as the pulse selection information PS. Then, in the current printing cycle TA, the first drive pulse DP1 is applied in the first period T1, and further, the third drive pulse DP3 is applied in the third period T3. As a result, in the current printing cycle TA, two large ink droplets are ejected and large dots are formed on the paper P.

  The non-print selection data SPx is data set so that the pulse selection information PS for selecting the second drive pulse DP2 is generated regardless of the logical arrangement of the print data SI. Therefore, when the non-print selection data SPx is input to the selection information generation unit 752, no matter which print data SI (HL) is input to the gate driver circuit 753, each drive element 62 is in the second period T2. The second drive pulse DP2 is applied, and no drive pulse is applied except during the second period T2. As a result, the ink is not ejected and the ink in the nozzle is slightly vibrated.

  Next, a specific configuration of the head drive circuit 61 will be described with reference to FIG. FIG. 9 illustrates a control circuit 70, an SP storage unit 72, an error check unit 74, and a discharge control unit 75 in the configuration of the head drive circuit 61.

  The error check unit 74 includes the verification data storage unit 741, the comparison circuit 742, and the determination circuit 743. The ejection control unit 75 includes the ejection data storage unit 751, the selection information generation unit 752, the gate driver circuit 753, and the selection unit 756.

  The ejection data storage unit 751 includes a shift register and a latch circuit as described above, and has a storage capacity capable of storing print control data SIn for one column. The ejection data storage unit 751 includes a print data storage unit 754 that stores print data SI and a selection data storage unit 755 that stores transfer selection data SPr.

  The verification data storage unit 741 also includes a shift register and a latch circuit, and has a storage capacity capable of storing print control data SIn for one column. The verification data storage unit 741 is also composed of a storage unit that stores the print data SI and a storage unit that stores the transfer selection data SPr.

  A transfer switching signal SW, a latch signal LAT, and the like are input from the controller 31 to the control circuit 70. When the transfer of the print control data SIn is started, the control circuit 70 controls the output of the selection signals SEL1 and SEL2 to switch the input destination of the print control data SIn, thereby changing the first print control data SIn1 to the verification data. The storage unit 741 stores the second print control data SIn2 in the ejection data storage unit 751.

  Specifically, for example, when a signal notifying the start of print job processing, that is, the start of transfer of print control data SIn in the first row and first column is input from the controller 31, the control circuit 70 selects the selection signal. SEL1 is set to H level and the selection signal SEL2 is set to L level. When the selection signal SEL1 is at the H level, the clock signal SCK and the print control data SIn are input to the verification data storage unit 741. As a result, the first print control data SIn1 which is the first transferred data is stored in the verification data storage unit 741.

  Upon receiving the transfer switching signal SW, the control circuit 70 sets the selection signal SEL1 to the L level at a timing between the transfer period of the first print control data SIn1 and the transfer period of the second print control data SIn2. Then, the selection signal SEL2 is set to H level. When the selection signal SEL2 is at the H level, the clock signal SCK and the print control data SIn are input to the ejection data storage unit 751. Thus, the second print control data SIn2 is stored in the ejection data storage unit 751.

  Note that after the second print control data SIn2 is stored in the ejection data storage unit 751, the control circuit 70 maintains the selection signal SEL1 at the L level and maintains the selection signal SEL2 at the H level. Accordingly, the print control data SIn for the first row and the second column and thereafter is stored in the ejection data storage unit 751.

  The comparison circuit 742 receives the first print control data SIn1 latched by the latch signal LAT from the verification data storage unit 741, and the second print data latched by the latch signal LAT from the ejection data storage unit 751. Print control data SIn2 is input. The comparison circuit 742 compares the first print control data SIn1 and the second print control data SIn2, and outputs a signal indicating the comparison result to the determination circuit 743. For example, the comparison circuit 742 outputs an L level signal if the logical arrangement of the first print control data SIn1 and the logical arrangement of the second print control data SIn2 match, and if these data do not match, the comparison circuit 742 outputs an H level. The signal is output.

  The determination circuit 743 outputs a determination signal JS indicating whether or not the first print control data SIn1 and the second print control data SIn2 match based on the input comparison result. For example, the determination circuit 743 sets the determination signal JS to H level when the first print control data SIn1 and the second print control data SIn2 match, and the first print control data SIn1 and the second print control data SIn2 When the two do not match, the determination signal JS is set to L level.

  The determination signal JS is input to the SP storage unit 72 and the selection unit 756. When the determination signal JS indicates a mismatch between the first print control data SIn1 and the second print control data SIn2, the SP storage unit 72 outputs the non-print selection data SPx to the selection unit 756. Further, the transfer selection data SPr is input to the selection unit 756 from the selection data storage unit 755 in the ejection data storage unit 751.

  When the determination signal JS indicates a match between the first print control data SIn1 and the second print control data SIn2, the selection unit 756 outputs the transfer selection data SPr to the selection information generation unit 752. On the other hand, when the determination signal JS indicates a mismatch between the first print control data SIn1 and the second print control data SIn2, the selection unit 756 outputs the non-print selection data SPx to the selection information generation unit 752.

Further, the print data storage unit 754 in the ejection data storage unit 751 outputs the print data SI to the gate driver circuit 753.
Here, the control circuit 70 outputs a determination control signal CNT that is valid for a predetermined period based on the input of the transfer switching signal SW. The determination control signal CNT is input to the determination circuit 743. The determination control signal CNT becomes valid before the determination process by the determination circuit 743 is started after the transfer switching signal SW is input. In addition, the determination control signal CNT is input after the print data SI in the first row and the first column and the transfer selection data SPr or the non-print selection data SPx are input to the selection information generation unit 752 and the gate driver circuit 753. The print control data SIn in the second column is invalidated before being input to the selection information generation unit 752 and the gate driver circuit 753.

  When the determination control signal CNT is valid, the determination circuit 743 outputs a determination signal JS. On the other hand, when the determination control signal CNT is invalid, the determination circuit 743 outputs the same signal as the determination signal JS indicating data matching, that is, an H level signal. As a result, when the print control data SIn for the first row and the second column is input to the ejection control unit 75, the selection information generation unit 752 stores the selection data in the ejection data storage unit 751 via the selection unit 756. The selection data SP included in the print control data SIn is input from the unit 755.

Note that the print data storage unit 754 includes the first shift register 81 and the second shift register 82 described above.
The selection information generation unit 752 generates decode data used by the decoder 87 of the gate driver circuit 753 for decoding processing based on the selection data SP input to the selection information generation unit 752 and sets the decode data in each decoder 87. Each decoder 87 decodes the input print data SI based on the decode data to generate pulse selection information PS. Next, each decoder 87 outputs the generated pulse selection information PS to the level shifter 88 in synchronization with the latch signal LAT and the channel signal CH.

  Note that the comparison circuit 742 and the determination circuit 743 can be formed of various logic circuits. In the determination circuit 743 configured as described above, when the determination control signal CNT is invalid, the determination circuit 743 does not have to determine whether the two data input to the comparison circuit 742 match. However, although the determination is performed, the same signal as the determination signal JS indicating data coincidence may be output regardless of the determination result.

Next, an example of transition of various signals input to and output from the control circuit 70 will be described with reference to FIG.
As shown in FIG. 10, the selection signal SEL1 is maintained at the H level and the selection signal SEL2 is maintained at the L level during the transfer period of the first printing control data SIn1 from the start of the transfer of the printing control data SIn. . Accordingly, the first print control data SIn1 is input to the verification data storage unit 741 to which the selection signal SEL1 is input.

  When the transfer switching signal SW rises at the timing between the transfer period of the first print control data SIn1 and the transfer period of the second print control data SIn2, the selection signal SEL1 and the selection signal SEL2 are inverted. Thereafter, the selection signal SEL1 is maintained at the L level and the selection signal SEL2 is maintained at the H level until the next transfer switching signal SW is input. Accordingly, the second print control data SIn2 and the print control data SIn for the first row and the second column are input to the ejection data storage unit 751 to which the selection signal SEL2 is input.

  When the latch signal LAT for latching the print data SI in the first row and the first column rises after the transfer switching signal SW rises, the determination control signal CNT is set to the H level. The determination control signal CNT is at the H level until at least the determination process by the determination circuit 743 is completed and the determination signal JS is output, and the selection data SP corresponding to the determination signal JS is output to the selection information generation unit 752. Maintained.

  For example, the determination control signal CNT may be maintained at the H level for a predetermined time in consideration of the time required for the determination process by the determination circuit 743, or the latch signal LAT for latching the print data SI in the first row and the second column. May be maintained at the H level until. A period during which the determination control signal CNT is maintained at the H level is a period during which the determination control signal CNT is valid. The determination control signal CNT may be made valid after the rise of the transfer switching signal SW and before the latch signal LAT for latching the print data SI in the first row and the first column.

  The determination signal JS is maintained at the H level during the period when the determination process by the determination circuit 743 is not performed, and is set to the H level when the determination result indicates a match between the two data. When indicating a data mismatch, it is set to L level.

  Here, as illustrated in FIG. 10, it is assumed that a determination signal JS indicating data mismatch is output at time t1. That is, the determination signal JS falls to the L level at time t1. Thereafter, the determination signal JS is maintained at the L level while the determination control signal CNT maintains the H level. When the determination control signal CNT falls to the L level, the determination signal JS rises to the H level. That is, the determination signal JS indicating the mismatch between the two data is output only during a period in which the determination control signal CNT is valid. When the determination signal JS indicating the coincidence of the two data is output at time t1, the determination signal JS is maintained at the H level throughout the period during which the determination control signal CNT is valid and the period during which the determination control signal CNT is invalid. .

  As a result, when the print data SI in the first row and the first column is input to the gate driver circuit 753, the result of the determination process by the determination circuit 743, that is, the first print control data SIn1 and the second print control data SIn2 match. Depending on whether or not to perform, transfer selection data SPr or non-printing selection data SPx is input to the selection information generation unit 752. Then, the print data SI is decoded using the selection data SP input to the selection information generation unit 752. When the print data SI from the first row and the second column is input to the gate driver circuit 753, the transfer selection data SPr is input to the selection information generation unit 752. Then, the print data SI is decoded using the transfer selection data SPr.

Incidentally, in FIG. 10, the first printing cycle TA is started from the first rise of the latch signal LAT, and the drive pulse of the drive signal COM is output.
Note that the output of the determination signal JS indicating whether or not the first print control data SIn1 and the second print control data SIn2 match, and the selection data SP corresponding to the determination signal JS is sent to the selection information generation unit 752. As long as the configuration is maintained until output, the transition of each signal may be different from the example shown in FIG. The switching of the storage units 741 and 751 to which the print control data SIn is input and the output of the determination signal JS are performed using other functions such as the latch signal LAT and the channel signal CH without using the transfer switch signal SW and the determination control signal CNT. You may control by the combination of the signal which has.

Next, a processing procedure performed by the printer 11 will be described with reference to FIGS. 11 and 12.
When a print job is input and processing is started, signals such as a drive signal COM and print control data SIn are transmitted from the controller 31 to the head drive circuit 61 through the flexible cable 65. At this time, the controller 31 executes the signal output sequence shown in FIG. 11, and the head drive circuit 61 executes the signal input sequence shown in FIG. First, the signal output sequence executed by the controller 31 will be described with reference to FIG.

  First, when processing of a print job is started, in step S11, the controller 31 outputs the print data SI and transfer selection data SPr in the first row and first column as the first print control data SIn1. Specifically, the controller 31 generates print data SI that can be used by the head drive circuit 61 from the print data, and transmits the print data SI in the first row and first column to the head unit 60 in synchronization with the clock signal SCK. . Further, the controller 31 reads transfer selection data SPr corresponding to the print mode designated in the received print job from the nonvolatile memory 43 and transmits it to the head unit 60 in synchronization with the clock signal SCK. The controller 31 writes the transfer selection data SPr in a memory such as the RAM 42. When the process of step S11 is completed, the process proceeds to step S12.

  In step S12, it is determined whether or not the output of the first print control data SIn1 has been completed. For example, the controller 31 counts the number of pulses of the clock signal SCK synchronized with the first print control data SIn1 with a counter (not shown) at the time of output, and the counted value becomes the data length of the first print control data SIn1. The output is determined to be complete when the corresponding predetermined value is reached. If the output is not completed (No at Step S12), the process returns to Step S11, the output of the first print control data SIn1 is continued, and when the output of the first print control data SIn1 is completed (Yes at Step S12), Step S13 Proceed to

In step S13, the controller 31 outputs a transfer switching signal SW. When the process of step S13 is completed, the process proceeds to step S14.
In step S14, the controller 31 outputs the print data SI in the first row and the first column and the transfer selection data SPr as the second print control data SIn2. Specifically, the controller 31 reads the print data SI and transfer selection data SPr in the first row and first column from the RAM 42 and outputs them to the head drive circuit 61 in synchronization with the clock signal SCK. When the process of step S14 is completed, the process proceeds to step S15.

  In step S15, the print data SI and transfer selection data SPr from the first row and the second column are output. The print control data SIn for the first row and the second column is output in synchronization with the clock signal SCK in order of one column every print cycle TA until the output of all the print data SI is completed.

In this way, the controller 31 performs the printing instructed by the print job by executing the signal output sequence shown in FIG.
On the other hand, in the head unit 60, the following signal input sequence shown in FIG.

  First, in step S21, the first print control data SIn1 is input to the head drive circuit 61. The first print control data SIn1 input by the receiving unit 71 is stored in the verification data storage unit 741 in the error check unit 74.

  In the next step S <b> 22, the second print control data SIn <b> 2 is input to the head drive circuit 61. The second print control data SIn2 input by the receiving unit 71 is stored in the ejection data storage unit 751 in the ejection control unit 75.

  In the next step S23, the first print control data SIn1 and the second print control data SIn2 are compared. That is, the comparison circuit 742 compares whether or not the first print control data SIn1 input from the verification data storage unit 741 matches the second print control data SIn2 input from the ejection data storage unit 751.

In the next step S24, it is determined whether or not the first print control data SIn1 and the second print control data SIn2 match (SIn1 = SIn2).
This determination process is performed by the determination circuit 743 based on a signal input from the comparison circuit 742 according to the comparison result. Then, the determination circuit 743 outputs a determination signal JS corresponding to the determination result. When the determination circuit 743 outputs a determination signal JS indicating that the first print control data SIn1 and the second print control data SIn2 match (Yes determination in step S24), the process proceeds to step S25. On the other hand, when the determination circuit 743 outputs the determination signal JS indicating that the first print control data SIn1 and the second print control data SIn2 do not match (No determination in step S24), the process proceeds to step S26.

  In step S25, ejection control based on the print data SI stored in the ejection data storage unit 751 is performed using the transfer selection data SPr. That is, the gate driver circuit 753 drives the drive element 62 and ejects ink droplets from the nozzles 162 based on the print data SI in the first row and first column being decoded using the transfer selection data SPr. Thus, the first printing by the discharge head 16 is performed. When the process of step S25 is completed, the process proceeds to step S27.

  On the other hand, in step S26, ejection control based on the print data SI stored in the ejection data storage unit 751 is performed using the non-print selection data SPx. That is, the gate driver circuit 753 drives the drive element 62 based on the print data SI in the first row and first column being decoded using the non-print selection data SPx. At this time, since the non-print selection data SPx is used, a pulse for finely vibrating the ink in the nozzle 162 is selected as a pulse to be applied to all the drive elements 62, and the ink from any of the nozzles 162 is selected. Drops are not ejected. When the process of step S26 is completed, the process proceeds to step S27.

  In step S27, discharge control based on the print data SI for the first row and the second column is performed using the transfer selection data SPr. That is, based on the fact that the print control data SIn input from the controller 31 is stored in the ejection data storage unit 751 and decoded using the transfer selection data SPr in which the stored print data SI is stored, the gate driver The circuit 753 drives the drive element 62 to eject ink droplets from the nozzle 162. Such a process is performed on the print data SI for one column every print cycle TA, and the print data SI for the first row and the second column are sequentially processed by repeating such a process.

  That is, when the first print control data SIn1 and the second print control data SIn2 match, the discharge control based on the print data SI in the first row and the first column using the transfer selection data SPr is performed, Ink is ejected from the pixel column in the first row and first column according to the print data SI.

  On the other hand, when the first print control data SIn1 and the second print control data SIn2 do not match, the non-print selection data SPx is used to perform discharge control based on the print data SI in the first row and first column. Ink is not ejected to the first pixel row. Thereafter, ejection control using the transfer selection data SPr is performed on the first and second pixel columns, and ink is ejected according to the print data SI.

  Of the processes performed by the printer 11, step S11 and step S14 are examples of the first step, step S24 is an example of the second step, and step S25 and step S26 are examples of the third step.

  As described above, after the print job data is input to the controller 31 and the processing is started, before the drive signal generation circuit 46 outputs the drive signal COM, the ink is driven by the drive of the transport motor 22. The period during which the paper P is transported overlaps the initial position for receiving ejection. In addition, the period before the drive signal generation circuit 46 outputs the drive signal COM overlaps the period in which the carriage 15 is accelerated and moved toward the position where ink is ejected by driving the carriage motor 20. When the paper P is transported to the initial position or when the carriage 15 is accelerated, the amount of drive of the motors 20 and 22 changes greatly, so that noise that affects data transferred through the flexible cable 65 is likely to occur. Further, when the paper P is transported, the discharge of the electrostatic charge charged on the paper P may become a noise source. Therefore, in the data transferred from the controller 31 to the head unit 60 during this period, transfer errors such as inversion of the logical value of the data due to noise and data shift in which the bit position of the data is shifted are likely to occur.

  In the present embodiment, the print control data SIn in the first row and the first column, which is data transferred in a period before the drive signal generation circuit 46 outputs the drive signal COM, is transferred twice. Then, the head drive circuit 61 compares the two input data to determine whether or not a logical value inversion or data shift has occurred in the data. If these data do not match, that is, the data In the case where a transfer error has occurred, the non-printing selection data SPx is used so that ink is not ejected to the first row and first pixel column.

  Compared to the case where ink is ejected from a nozzle that should not eject ink based on the print control data SIn in which a transfer error has occurred, the ink is applied to the first pixel column located at the end of the first row. The fact that no ink is discharged suppresses the deterioration of the quality of the printing result.

  In the period before the printing cycle TA is started, there is more time available for the transfer of the printing control data SIn than after the printing cycle TA is started. That is, the period before the drive signal generation circuit 46 outputs the drive signal COM is a period in which a data transfer error is likely to occur and the transfer time is less limited. Therefore, transferring the data to be transferred in this period twice to verify the transfer error and performing the discharge control according to the result suppresses the decrease in the printing speed of the printer 11 and improves the quality of the printing result. The effect is high in that the reduction can be suppressed.

In the above embodiment, the first print control data SIn1 is an example of the first data, and the second print control data SIn2 is an example of the second data.
As described above, according to the printer 11 of the first embodiment, the following effects can be obtained.

  (1) Print control data SIn is transferred twice from the controller 31 to the head unit 60 in the period before the drive signal generation circuit 46 outputs the drive signal COM, which is a period in which a lot of noise occurs, and these data match. When not, that is, when a transfer error has occurred in the data, a pulse that does not eject ink is applied to the drive element 62. Accordingly, ink is not ejected based on the erroneous print control data SIn. According to such a configuration, it is possible to suppress a decrease in quality of a target formed by ink ejection.

  (2) During the period during which the paper P is transported, noise is particularly likely to occur due to the motor being driven to transport the paper P, and data transfer errors based on the noise are likely to occur. Since the above configuration is applied during a period in which such a data transfer error is likely to occur, it is possible to appropriately suppress a reduction in quality of a target formed by ink ejection.

  (3) During the period in which the carriage 15 is accelerated, noise is particularly likely to occur due to the motor being driven to move the carriage 15, and data transfer errors based on noise are likely to occur. Since the above configuration is applied during a period in which such a data transfer error is likely to occur, it is possible to appropriately suppress a reduction in quality of a target formed by ink ejection.

(Second Embodiment)
Hereinafter, a second embodiment in which the liquid discharge apparatus and the liquid discharge method are embodied will be described with reference to the drawings. In the second embodiment, the process when it is determined that the first print control data SIn1 and the second print control data SIn2 do not match is different from the first embodiment. Below, it demonstrates centering on difference with 1st Embodiment, about the structure similar to 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  As shown in FIG. 13, in this embodiment, when the first print control data SIn1 and the second print control data SIn2 do not match, the determination circuit 743 outputs an error signal ES. The error signal ES is input from the head drive circuit 61 to the controller 31. When the error signal ES is input to the controller 31, the main control unit 41 causes the data output control unit 47 to output the print control data SIn for the first line to the head drive circuit 61 again. In general, when the output of the print control data SIn for one line is completed, the main control unit 41 drives the transport motor 22 via the motor drive circuit 52. However, when the error signal ES is input to the controller 31, the main control unit 41 determines the interval between the output of the first line of print control data SIn and the output of the second line of print control data SIn. Then, the conveyance motor 22 is not driven, and the paper P is stopped at the initial position. Then, in response to the fact that the error signal ES is not input after the output of the print control data SIn, the controller 31 restarts the conveyance of the paper P for each pixel row.

  Processing in the controller 31 and processing in the head drive circuit 61 in this embodiment will be described in detail with reference to a signal output sequence executed by the controller 31 and a signal input sequence executed by the head drive circuit 61.

First, the signal output sequence executed by the controller 31 will be described with reference to FIG.
As shown in FIG. 14, in steps S31 to S34, the same processes as in steps S11 to S14 in FIG. 11 of the first embodiment are performed. That is, the controller 31 outputs the print data SI and the transfer selection data SPr in the first row and the first column as the first print control data SIn1, and when the output of the first print control data SIn1 is completed, the transfer switching signal SW is output. Output. Then, the controller 31 outputs the print data SI in the first row and the first column and the transfer selection data SPr as the second print control data SIn2.

Subsequently, in step S35, the controller 31 outputs the print control data SIn for the first row and the second column and thereafter in order for each column in synchronization with the clock signal SCK.
Next, in step S36, it is determined whether or not the output of the print control data SIn for all the columns in the first row has been completed. If the output is not completed (No at Step S36), the process returns to Step S35, the output of the print control data SIn is continued, and when the output of the print data SI for all the columns of the first row is completed (Yes at Step S36). The process proceeds to step S37.

  In step S37, it is determined whether an error signal ES has been received. That is, it is determined whether the controller 31 has received the error signal ES from the head drive circuit 61, in other words, whether the error signal ES has been input to the main control unit 41.

  If the error signal ES has not been received, that is, if no error has been detected in the print control data SIn in the first row and first column by the head drive circuit 61, the process proceeds to step S38. In step S38, the print data SI and transfer selection data SPr for the second and subsequent rows are output in order for each column in synchronization with the clock signal SCK.

  At this time, the main control unit 41 drives the transport motor 22 via the motor drive circuit 52 after outputting the print control data SIn on the first line. For the second and subsequent lines, the main control unit 41 drives the transport motor 22 every time the print control data SIn for one line is output. As a result, the paper P is transported in the transport direction Y by the length of one pixel line for each output of the print control data SIn for one line.

  When the error signal ES is received, that is, when an error is detected in the print control data SIn in the first row and the first column in the head driving circuit 61, the processing is repeated from step S31. At this time, the main control unit 41 repeats the processing from step S31 without driving the transport motor 22. The carriage motor 20 is driven as usual, and the carriage 15 is moved toward a position where ink is ejected with respect to the first pixel row.

In this way, the controller 31 performs the printing instructed by the print job by executing the signal output sequence shown in FIG.
On the other hand, in the head unit 60, the following signal input sequence shown in FIG.

  As shown in FIG. 15, in steps S41 to S44, the same processes as in steps S21 to S24 in FIG. 12 of the first embodiment are performed. That is, after the first print control data SIn1 is stored in the verification data storage unit 741, the second print control data SIn2 is stored in the discharge data storage unit 751, and the comparison circuit 742 performs the first print control data SIn1. Are compared with the second print control data SIn2. Then, the determination circuit 743 determines whether or not the first print control data SIn1 and the second print control data SIn2 match (SIn1 = SIn2), and a determination signal JS corresponding to the determination result is output. The

  When the determination circuit 743 outputs a determination signal JS indicating that the first print control data SIn1 and the second print control data SIn2 match (Yes determination in step S44), the process proceeds to step S45. On the other hand, when the determination circuit 743 outputs a determination signal JS indicating that the first print control data SIn1 and the second print control data SIn2 do not match (No determination in step S44), the process proceeds to step S46.

  In step S45, ejection control based on the print data SI is performed using the transfer selection data SPr. That is, first, ejection control based on the print data SI of the first row and the first column stored in the ejection data storage unit 751 is performed using the transfer selection data SPr. Subsequently, for the first row and the second column and thereafter, the print control data SIn input from the controller 31 is stored in the ejection data storage unit 751 and stored print data using the stored transfer selection data SPr. The discharge control based on SI is repeated.

In step S46, the determination circuit 743 outputs an error signal ES. The error signal ES is input from the head drive circuit 61 to the controller 31.
Subsequently, in step S47, ejection control based on the print data SI of the first line is performed using the non-print selection data SPx. That is, first, ejection control based on the print data SI of the first row and the first column stored in the ejection data storage unit 751 is performed using the non-print selection data SPx. Subsequently, the print control data SIn input from the controller 31 is also stored in the ejection data storage unit 751 up to the last column of the first row for the first row and the second column and thereafter, using the non-print selection data SPx. The discharge control based on the stored print data SI is repeated.

  When the process of the print data SI for the first line using the non-print selection data SPx is completed, the print control data SIn for the first line and the first column is input again from the controller 31, and the head drive circuit 61 starts the process from step S41. Repeated.

  As described above, when the first print control data SIn1 and the second print control data SIn2 coincide with each other, the discharge control based on the print data SI in the first row and the first column and thereafter is performed using the transfer selection data SPr. Ink is ejected from the pixel row in the first row and first column according to the print data SI.

  On the other hand, when the first print control data SIn1 and the second print control data SIn2 do not match, the ejection control using the non-print selection data SPx is performed for all the pixel columns included in the first pixel row. Is called. Therefore, in the first row, ink is not ejected to all the pixel columns. Then, the conveyance of the paper P is not performed, and the carriage 15 is arranged at the ink ejection position for the first pixel row, and the print control data SIn for the first row is transferred again from the controller 31 to the head drive circuit 61. Is done. Therefore, if the first print control data SIn1 and the second print control data SIn2 coincide with each other at the time of the transfer again, ejection based on the print data SI in the first row and the first column using the transfer selection data SPr. Control is performed. Thus, ink is ejected from the pixel row of the first row and the first column according to the print data SI.

Next, with reference to FIG. 16, an example of transition of various signals input to and output from the control circuit 70 in the second embodiment will be described.
As shown in FIG. 16, for example, when a start signal STA, which is a signal indicating the start of transfer of the print control data SIn, is input from the controller 31 to the head drive circuit, the selection signal SEL1 is received in response to the rise of the start signal STA. Is set to H level, and the selection signal SEL2 is set to L level. Thereafter, during the transfer period of the first print control data SIn1, the selection signal SEL1 is maintained at the H level, and the selection signal SEL2 is maintained at the L level. Accordingly, the first print control data SIn1 is input to the verification data storage unit 741 to which the selection signal SEL1 is input.

  When the transfer switching signal SW rises at the timing between the transfer period of the first print control data SIn1 and the transfer period of the second print control data SIn2, the selection signal SEL1 and the selection signal SEL2 are inverted. Thereafter, the selection signal SEL1 is maintained at the L level, and the selection signal SEL2 is maintained at the H level. Accordingly, the second print control data SIn2 and the print control data SIn for the first row and the second column are input to the ejection data storage unit 751 to which the selection signal SEL2 is input.

  When the latch signal LAT for latching the print data SI in the first row and the first column rises after the transfer switching signal SW rises, the determination control signal CNT rises. In the present embodiment, the determination control signal CNT is a signal that defines the update timing of the determination signal JS, and is a signal that becomes an H level only at the timing when the first latch signal LAT rises after the transfer switching signal SW rises. is there.

  Therefore, for example, if a determination result indicating data mismatch is output at time t1, the determination circuit 743 receives the rising edge of the determination control signal CNT and outputs a determination signal JS indicating data mismatch. That is, determination signal JS is set to L level, and thereafter, determination signal JS is maintained at L level until determination control signal CNT rises anew.

  When the transfer of the print control data SIn for all the columns in the first row is completed based on the error signal ES being input to the controller 31, the print control data SIn for the first row is again transferred from the first print control data SIn1. Is repeated. That is, when the start signal STA is input and the rising edge of the start signal STA is received, the selection signal SEL1 is set to H level and the selection signal SEL2 is set to L level. Thereafter, when the transfer switching signal SW rises, the selection signal SEL1 and the selection signal SEL2 are inverted. Accordingly, the first print control data SIn1 is input to the verification data storage unit 741, and the second print control data SIn2 and the print control data SIn for the first row and the second column are stored in the ejection data storage unit 751. Entered.

  When the latch signal LAT for latching the print data SI in the first column rises after the transfer switching signal SW rises, the determination control signal CNT rises. For example, if a determination result indicating data coincidence is output at time t2, the determination circuit 743 receives a rising edge of the determination control signal CNT and outputs a determination signal JS indicating data coincidence. That is, determination signal JS is set to H level, and thereafter determination signal JS is maintained at H level.

  Thus, when the first print control data SIn1 and the second print control data SIn2 do not match, the ejection control using the non-print selection data SPx is performed for all the pixel columns in the first row. The retransfer of the print control data SIn on the first line and the determination of whether or not the first print control data SIn1 and the second print control data SIn2 match are repeated until these data match.

  Note that the output of the determination signal JS indicating the determination result of whether or not the first print control data SIn1 and the second print control data SIn2 match is the discharge control based on the print control data SIn on the first line. The transition of each signal may be different from the example shown in FIG. The switching of the storage units 741 and 751 to which the print control data SIn is input and the output of the determination signal JS are performed using the latch signal LAT, the channel signal CH, etc. It may be controlled by a combination of signals having other functions.

  As described above, in the second embodiment, when the first print control data SIn1 and the second print control data SIn2 do not match, the non-print selection data SPx is used for the first pixel row. Ink is not ejected and ink is ejected again for the first pixel row. Therefore, it is possible to obtain a high-quality printing result with the erroneous ejection suppressed without wasting the paper P.

According to the printer 11 of the second embodiment described in detail above, the following effects can be obtained in addition to the effects (1) to (3) of the first embodiment.
(4) When a transfer error occurs in the print control data SIn on the first row and the first column, the print control data SIn on the first row and the first column is retransmitted, so that the drive element 62 is driven based on the retransmitted data. Is possible. Therefore, it is formed by ejecting ink as compared with a configuration in which ink is not ejected at all to the first row and first pixel column where ink is scheduled to be ejected based on data in which a transfer error has occurred. The quality of the object is increased.

In addition, each said embodiment can also be changed into the following forms.
In each of the above-described embodiments, the first print control data SIn1 is input to the verification data storage unit 741, and the second print control data SIn2 is input to the discharge data storage unit 751 to perform discharge control by the discharge control unit 75. Used. Instead, the second print control data SIn2 is input to the verification data storage unit 741, and the first print control data SIn1 is input to the discharge data storage unit 751 to be used for discharge control by the discharge control unit 75. May be. Further, for example, the print data SI of the first print control data SIn1 and the transfer selection data SPr of the second print control data SIn2 may be used for ejection control, or the print data SI of the second print control data SIn2 The transfer selection data SPr of the first print control data SIn1 may be used for discharge control. In short, the data used for the discharge control may be data transferred earlier or data transferred later.

  In each of the above embodiments, the first print control data SIn1 and the second print control data SIn2 are data having the same logical arrangement, but the first print control data SIn1 is the logic of the second print control data SIn2. May be inverted data. That is, of the two data transferred from the controller 31 to the head drive circuit 61, the data input to the ejection data storage unit 751 is the print control data SIn in the first row and the first column, and the verification data storage unit The data input to 741 may be data obtained by inverting the logic of the print control data SIn in the first row and first column. According to such a configuration, the accuracy of data comparison in the comparison circuit 742 is increased. In short, the first print control data SIn1 only needs to be data that can generate the same logical arrangement as the second print control data SIn2.

  In each of the above embodiments, the data transferred twice in the period before the drive signal COM is output is the print control data SIn including the print data SI and the selection data SP. Instead, only the print data SI may be transferred twice, or only the selection data SP may be transferred twice. For example, after only the print data SI is transferred twice, the selection data SP is transferred, and whether or not a transfer error has occurred in the data may be determined based on a comparison of the two print data SI. . Alternatively, after only the selection data SP is transferred twice, the print data SI is transferred, and whether or not a transfer error has occurred in the data may be determined based on a comparison of the two selection data SP. .

  In each of the above embodiments, the non-print selection data SPx is the selection data SP for selecting a drive pulse that causes the ink in the nozzle to vibrate without ejecting ink from the nozzle. The selection data SP for selecting a drive pulse that does not cause ink to be ejected from the nozzle, in other words, data indicating whether or not each waveform included in the drive signal can be applied indicates non-ejection of ink from the nozzle. For example, the non-print selection data SPx may be selection data SP for selecting a waveform applied to the drive element 62 so as not to vibrate ink in the nozzles. If the selection data SP for selecting a drive pulse that slightly vibrates the ink in the nozzle is the non-print selection data SPx, a period in which ink is not ejected may be provided in order to suppress erroneous ejection due to a transfer error. It is possible to suppress the increase in the viscosity of the ink in the nozzle during such a period.

  In the second embodiment, even when the print control data SIn for the first row is retransmitted, the print control data SIn for the first row and the first column is transferred twice, and the head drive circuit 61 stores these data. A comparison was made. Instead, when the print control data SIn on the first line is retransmitted, the print control data SIn on the first line and the first column is transferred only once, and it is determined that there is no transfer error. Discharge control based on the print control data SIn in the first row may be performed. When the print control data SIn on the first line is retransmitted, the paper P is already placed at the initial position from which ink is ejected, so the print control data SIn on the first line and the first column is transferred first. Compared to the above, the drive amount of the transport motor 22 is small, and a data transfer error caused by noise hardly occurs. Accordingly, only when the print control data SIn on the first line is transferred for the first time, the print control data SIn on the first line and the first column is transferred twice, and the selection data SP corresponding to the comparison result of these data is displayed. Even if it is the structure used, the fall of the quality of the object formed by discharge of an ink can be suppressed.

  -In 2nd Embodiment, the structure by which the error check with respect to the printing control data SIn of the 1st line is performed 3 times or more may be sufficient. At this time, the controller 31 is provided with a counter that counts the number of times the error signal ES is input. When the measured value of the counter reaches a predetermined value, the display unit 26 indicates that the print control data SIn cannot be transferred. The printer 11 may be configured to display on the screen.

  In each of the above embodiments, before the output of the drive pulse is started, a period during which the paper P is transported to a position where ink is discharged and a period during which the carriage 15 is accelerated toward the position where ink is discharged. When these periods overlap, the print control data SIn in the first row and first column was transferred. The present invention is not limited to this, and the print control data SIn in the first row and the first column may be transferred when only the paper P is transported or when only the acceleration movement of the carriage 15 is performed. Further, the conveyance of the paper P and the acceleration movement of the carriage 15 may be performed only during a period in which one of the first print control data SIn1 and the second print control data SIn2 is transferred. Even in such a case, since noise is generated by driving the transport motor 22 or the carriage motor 20, the configuration of each of the above embodiments is applied, thereby suppressing the deterioration of the quality of the target formed by ink ejection. Is obtained.

  In each of the above embodiments, only the print control data SIn in the first row and the first column is transferred twice, but the print control data SIn in the first column is twice in at least one of the rows other than the first row. The ejection control may be performed using the selection data SP that is transferred and selected according to the comparison result of the two data. As described above, since the carriage 15 is accelerated and decelerated during the period between the ejection of ink to pixels in adjacent rows, when the print control data SIn for the first column of each row is transferred, the carriage motor 20 Noise due to driving is likely to occur. Therefore, according to the configuration in which the print control data SIn in the first column is transferred twice for the lines other than the first line, and the ejection control using the selection data SP corresponding to the comparison result of the two data is performed. Further, the deterioration of the quality of the object formed by the ink ejection is further suppressed.

  A printer (printing apparatus) as an example of a liquid ejection apparatus is not limited to a serial printer, and may be a line printer or a page printer. For example, the liquid ejecting apparatus may be a line printer including a line head. The line printer is configured by connecting a controller as an example of a control unit in the apparatus main body and a head unit including a line head through a flexible cable. For example, the line head may be a multi-head type head in which a plurality of ejection heads are arranged in a line or zigzag. In the case of this type of multi-head type, the controller is connected to each of a plurality of ejection heads constituting the line head via a flexible cable, or the controller is connected to at least one of the plurality of ejection heads via a flexible cable. Further, a configuration in which the connection destination discharge head is sequentially connected to the adjacent discharge head may be employed. Furthermore, the line head may be configured to be movable up and down during cleaning.

  In the above embodiment, the controller 31 that is an example of the control unit is realized by the cooperation of software by a computer that executes a program and hardware by an electronic circuit such as an ASIC. The various functions may be configured only by software that causes the computer to function as various functional units, or may be configured only by hardware.

  -A flexible cable is not limited to a flexible flat cable, What is necessary is just a flexible cable. For example, the controller 31 and the head unit 60 may be connected via a plurality of flexible cables. Note that the flexible cable may be configured to have at least one signal line, but a configuration including a plurality of signal lines is preferable for the purpose of reducing the number of cables.

  -The liquid ejection device is not limited to an ink jet printer (printing device), but is a liquid other than ink, for example, a liquid material in which particles of a functional material are dispersed or mixed in a liquid, a fluid such as a gel A liquid discharge apparatus that discharges water may also be used. For example, a liquid ejection device ejects a liquid material that contains materials such as electrode materials and color materials (pixel materials) used in the manufacture of liquid crystal displays, EL (electroluminescence) displays, and surface-emitting displays in a dispersed or dissolved state. It may be a liquid ejection device. Furthermore, the liquid ejection device may be a liquid ejection device that ejects biological organic materials used in biochip manufacturing, or a liquid ejection device that ejects a liquid that is used as a precision pipette as a sample. Furthermore, the liquid ejecting device is an ultraviolet curable resin for forming liquid ejecting devices that pinpoint lubricant oil to precision machines such as watches and cameras, and micro hemispherical lenses (optical lenses) used for optical communication elements. A liquid discharge apparatus that discharges a transparent resin liquid such as a liquid onto the substrate, or a liquid discharge apparatus that discharges an etching liquid such as acid or alkali to etch the substrate or the like may be used. Moreover, the liquid discharge apparatus which discharges a liquid and manufactures a three-dimensional structure may be sufficient.

  DESCRIPTION OF SYMBOLS 11 ... Printer as an example of a liquid discharge apparatus, 15 ... Carriage, 16 ... Discharge head, 162 ... Nozzle, 25 ... Operation part, 26 ... Display part, 31 ... Controller which is an example of a control part, 41 ... Main control part, Reference numeral 411: Discharge control signal generator, which is an example of a data generator, 46: Drive signal generator, which is an example of a drive signal generator, 47: Data output controller, 60: Head unit, 61: Head drive circuit, 62 ... Drive element 63... Discharge unit 64. Discharge unit group 65. Flexible cable 70 control circuit 72. SP storage unit 74 error check unit 741 verification data storage unit 742 comparison circuit 743 ... Judgment circuit 75... Ejection control unit 751... Ejection data storage unit 752... Selection information generation unit 753. , SIn, SIn (K), SIn (C), SIn (M), SIn (Y) ... print control data, COM ... drive signal, SP ... selection data, SPr ... transfer selection data, SPx ... non-print selection data , SI ... print data, SW ... transfer switching signal, SEL1, SEL2 ... selection signal, CNT ... determination control signal, JS ... determination signal, ES ... error signal, DP1, DP2, DP3, DP4 ... drive pulse, P ... of the medium Paper as an example, X: scanning direction, Y: transport direction.

Claims (5)

A plurality of driving elements for discharging liquid;
A drive signal generator for generating a drive signal including a plurality of waveforms for driving the drive element;
Generating control data for determining the size of a liquid dot formed by driving the driving element for each driving element, and selection data for associating the size of the dot with applicability of each waveform; At least one of the control data and the selection data is first data, and a data generation unit that generates second data that matches the first data;
A data output control unit that outputs the control data, the selection data, and the second data generated by the data generation unit before the drive signal generation unit outputs the drive signal;
An error check unit for determining whether or not the first data and the second data match among the data input from the data output control unit;
A storage unit that stores non-ejection selection data indicating non-ejection of the liquid by the applicability of each waveform;
When the result of the determination is coincident, application and non-application of the waveform to the drive element are controlled based on the control data and the selection data input from the data output control unit, and the result of the determination is A discharge control unit that controls application and non-application of the waveform to the drive element based on the control data and the non-discharge selection data input from the data output control unit when they do not match;
A head unit having the drive element, the error check unit, the storage unit, and the ejection control unit;
A control unit having the drive signal generation unit, the data generation unit, and the data output control unit;
A liquid ejection apparatus, comprising: a flexible cable which is a transmission path for the control data, the selection data, and the second data and electrically connects the control unit and the head unit. The error check unit outputs an error signal indicating the mismatch to the control unit when the result of the determination is a mismatch.
The liquid ejection apparatus according to claim 1, wherein when the error signal is input to the control unit, the data output control unit outputs the first data again to the ejection control unit. At least one of the period in which the data output control unit outputs the first data and the period in which the data output control unit outputs the second data, the medium that receives the liquid discharge receives the liquid discharge. The liquid ejection apparatus according to claim 1, wherein the liquid ejection apparatus is included in a period during which the liquid is conveyed to a position. A carriage that reciprocates by mounting the head unit;
At least one of a period in which the data output control unit outputs the first data and a period in which the data output control unit outputs the second data is accelerated and moved toward a position where the carriage ejects the liquid. It is contained in the period to perform. The liquid discharge apparatus as described in any one of Claims 1-3 characterized by the above-mentioned. A liquid ejection method in which a head drive circuit controls a plurality of drive elements based on drive signals, control data, and selection data output by a control unit via a flexible cable, and ejects liquid.
The drive signal includes a plurality of waveforms for driving the drive element,
The control data determines the size of a liquid dot formed by driving the driving element for each driving element,
The selection data is data for associating the size of the dots with the applicability of each waveform,
The control unit outputs first data including at least one of the control data and the selection data and second data that matches the first data before outputting the drive signal to the head drive circuit. A first step to:
A second step in which the head driving circuit determines whether or not the first data and the second data input from the control unit match;
A third step in which the head drive circuit controls application and non-application of the waveform to the drive element based on the control data and the selection data;
Data indicating non-ejection of the liquid by the applicability of each waveform is non-ejection selection data, and when it is determined in the second step that the first data and the second data do not match, the first data In the third step, the non-ejection selection data is used as the selection data.

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