JP2016150567A - Liquid discharge device and liquid discharge method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid discharge device and a liquid discharge method which can cope with specifications putting priority on quality not allowing a defect in printing due to noise and specifications not putting priority on the quality in accordance with a user's need.SOLUTION: A controller on a body side of a printer transmits data necessary for control to a head unit through a flexible cable. A head drive circuit in the head unit inputs selection data (S21), and then inputs printing control data including printing data SI and verification data CP (S22, S23). In a case in an erroneous discharge determination mode (affirmative determination in S24), the selection data SP and the verification data CP are compared to each other (S25), and it is determined whether or not SP=CP is applied (S26). If SP=CP is applied, discharge control is performed on the basis of the printing data SI (S27). If SP=CP is not applied, an error signal is output (S28).SELECTED DRAWING: Figure 13

Description

  The present invention relates to a liquid discharge apparatus such as an ink jet printer and a liquid discharge method.

  2. Description of the Related Art Conventionally, as an example of this type of liquid ejection apparatus, an ink jet printing apparatus having an ejection head that ejects liquid such as ink from nozzles is widely known (for example, Patent Document 1). Patent Document 1 discloses a printing apparatus having a configuration in which a controller (an example of a control unit) provided in a printing apparatus main body and a head unit such as a print head that discharges liquid such as ink are connected via a flexible cable. Has been. The head unit is provided with a plurality of ejection units that are driven to eject liquid and eject ink droplets from the nozzles, and a head drive circuit that drives each ejection unit. Various data and signals are input to the head unit from the controller on the main body side through the flexible cable.

  The controller on the main body side includes a drive signal generation circuit that generates a drive signal for driving the plurality of ejection units and outputs the drive signal to the head unit. Further, the controller generates print data for controlling application and non-application of the drive signal to each ejection unit. Further, the controller acquires selection data (pattern data) that defines which drive pulse is selected from among a plurality of drive pulses included in the drive signal for each value of the print data. Then, the controller sequentially transmits one print control data (an example of an integrated control signal) including the print data and the selection data to the head unit.

  In the head unit, based on the received print data and selection data, when a part of the drive pulses included in the drive signal according to the value of the print data is applied to the ejection unit, The discharge unit discharges droplets having a size corresponding to the above. As a result, a liquid dot corresponding to the selected drive pulse is formed on the medium.

  Further, for example, in Patent Document 2, print data and selection data being transmitted through a flexible cable are input to the head drive circuit with incorrect values due to noise generated when the switch circuit in the head drive circuit is turned on / off. A printer that prevents this from occurring is disclosed. In this printer, the print data stop control unit provided in the controller on the main body side temporarily stops the transfer of print data, selection data, and clock signal at the noise generation timing based on the channel signal (switch signal). These data are transferred avoiding the timing of noise generation.

JP 2007-112149 A JP 2010-120181 A

  By the way, in a printer or the like, the distance over which the head unit is scanned becomes longer in proportion to the size of the medium to be printed. When the head unit is scanned over a long distance, wiring for transferring data to the head unit also becomes long. As described above, when the wiring length becomes long, it becomes easy to be influenced by disturbance noise. A technique for suppressing the influence of disturbance noise is disclosed in Patent Document 2. However, Patent Document 2 takes measures against specific noise when the switch circuit is turned on and off. However, when the flexible cable is deformed in the scanning process of the head unit, it comes into contact with a frame or other parts in the apparatus main body, or static electricity generated due to the deformation of the flexible cable itself becomes a source of noise. Since the generation timing of this type of noise cannot be specified, even if the technique described in Patent Document 2 is used, the influence of this type of noise cannot be suppressed.

  When a data shift in which data being transmitted is shifted due to this type of noise on the wiring, the head driving circuit inputs wrong data. In this case, ink droplets are not ejected from the nozzles that should eject ink droplets in the ejection head, or ink droplets are ejected from nozzles that should not eject ink droplets, resulting in small print defects (printing errors). May occur.

  In the case of a printed matter in which quality is given priority over productivity according to user needs, if such a small defect exists, the quality requested by the user should not be satisfied and printing should be failed. On the other hand, in the case of a printed matter that does not give priority to quality, there may be no problem with this type of small defect. In the conventional printing apparatus, when such a small defect due to noise is present in the print of the former needs, it is difficult for the user to notice the defect.

  In addition, even for line printers, not just serial printers, in the configuration where the controller on the main unit and the head unit are connected through wiring such as a flexible cable, noise is generated due to various causes. Exists.

  An object of the present invention is to provide a liquid ejecting apparatus and a liquid ejecting apparatus capable of complying with both a specification that prioritizes quality that does not allow printing defects caused by noise and a specification that does not prioritize quality in accordance with user needs. It is to provide a method.

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 drive signal generation unit that generates a drive signal for ejecting liquid, a first ejection unit that receives the drive signal and ejects the liquid, and receives the drive signal. A second discharge section that discharges the liquid; a discharge section group that includes a plurality of discharge sections including the first discharge section and the second discharge section; and application of the drive signal to the first and second discharge sections. And a control signal generation unit that generates an integrated control signal that controls non-application, a first discharge control signal that controls the first discharge unit, and a second discharge unit that controls the integrated control signal. A discharge control signal distribution unit that distributes to a second discharge control signal, an error check unit that performs an error check of the integrated control signal, the discharge unit group, the discharge control signal distribution unit, and the error check And a head unit having A control unit having the drive signal generation unit and a control signal generation unit, and a flexible cable for electrically connecting the control unit and the head unit, and the control unit includes the error An error check selection unit for selecting whether the check in the check unit is valid or invalid is included.

  According to this configuration, the error check selection unit included in the control unit selects whether to enable or disable the error check by the error check unit. When the check is validated, the error check unit performs an error check on the integrated control signal. When the check is invalidated, the error check unit does not perform an error check of the integrated control signal. Therefore, an error check can be selected when a high quality is required for a liquid discharge formed product (for example, a printed material) formed by discharging a liquid, and an error check can be selected when a high quality is not required. Therefore, according to the user's needs, it is possible to deal with both specifications that prioritize quality that does not allow printing defects due to noise and specifications that do not prioritize quality.

In the liquid ejection apparatus, it is preferable that the ejection control signal distribution unit includes a correction unit that corrects the current integrated control signal in which an error has occurred in the check of the error check unit.
According to this configuration, the current integrated control signal in which an error is detected by the error check unit is corrected by the correction unit. Therefore, compared with the case where the liquid is discharged with the current integrated control signal including an error, the quality of the liquid discharge formed product can be improved by discharging the liquid using the corrected current integrated control signal.

  In the liquid ejection apparatus, the correction unit includes a storage unit that stores the integrated control signal or the first and second ejection control signals, and the previous integrated control signal or the previous storage stored in the storage unit. It is preferable that correction is performed by using the first and second discharge control signals as the current integrated control signal or the current first and second discharge control signals.

  According to this configuration, when an error occurs due to the error check, the previous integrated control signal or the first and second discharge control signals stored in the storage unit are the current integrated control signal or the current first and second The second discharge control signal is used. In this and the previous integrated control signal, there is a high possibility that the arrangement of the ejection positions from which the liquid in the ejection unit group is ejected is similar. For example, the line formed by the ejected liquid dots becomes thicker or thinner. Therefore, compared with the case of discharging liquid based on the current integrated control signal in which an error has occurred, the degree of quality deterioration of the liquid discharge formed product can be reduced.

  In the liquid ejection apparatus, the control unit sends a reference signal for checking to the head unit, and then sends an integrated control signal generated by the control signal generation unit to the head unit. Including a checked signal having the same signal value as at least a part of a signal value of a reference signal, wherein the error check unit includes a storage unit for storing the reference signal, and the checked signal in the integrated control signal and the checked signal It is preferable to perform an error check based on the reference signal stored in the storage unit.

  According to this configuration, the control unit sends the reference signal for checking to the head unit before transmitting the integrated control signal to the head unit, and the reference data that is the signal content of the reference signal is stored in the storage unit. Thereafter, the control unit transmits an integrated control signal including a checked signal having the same signal value as at least a part of the signal value of the reference signal. Therefore, the error check unit can relatively accurately check the error of the integrated control signal based on the checked signal and the reference signal in the current integrated control signal.

  In the liquid ejection apparatus, the drive signal includes a plurality of drive pulses, and the control signal generation unit includes the ejection control signal and at least one drive pulse to be applied to the ejection unit among the plurality of drive pulses. It is preferable that a selection signal indicating a correspondence relationship is further acquired and the selection signal is used as the reference signal for checking.

  According to this configuration, the error check is performed using the selection signal acquired by the control signal generation unit as the reference signal for checking. That is, the error check unit performs an error check based on the integrated control signal and the selection signal. For this reason, there is no need to prepare a reference signal dedicated to checking that is not used for liquid ejection control. In addition, since the selection signal can be used for both the liquid discharge control and the check, for example, by delaying the transmission start of the integrated control signal by transmitting an extra signal not related to the discharge control such as a reference signal dedicated to the check. Can be avoided.

  In the liquid ejection apparatus, the integrated control signal includes a checked signal including the selection signal, and the error check unit performs an error check of the integrated control signal based on the selection signal and the checked signal. Preferably it is done.

  According to this configuration, an error check of the integrated control signal is performed based on the checked signal and the selection signal included in the integrated control signal. Further, since the checked signal includes a selection signal, if there is no error, the liquid ejection control can be performed using the same signal portion as the selection signal included in the checked signal instead of the selection signal.

In the liquid ejection apparatus, it is preferable that the integrated control signal includes a checked signal that is a part of the selection signal.
According to this configuration, since the checked signal included in the integrated control signal is a part of the selection signal, the signal length of the integrated control signal can be shortened and shortened compared to the case where the checked signal is the entire selection signal. Therefore, the integrated control signal can be transmitted to the head unit at a high speed. Therefore, for example, the liquid discharge process can be speeded up.

  The liquid ejecting apparatus includes an operation unit operated to input an instruction, and the error check selection unit validates the error check by the error check unit based on the instruction input from the operation unit. It is preferable to select whether to invalidate.

  According to this configuration, the user can select whether to enable or disable the error check by the error check unit by operating the operation unit according to needs. Therefore, for example, it is possible to avoid the inconvenience that the error check that is not desired by the user is arbitrarily selected, which may occur when the check is enabled or disabled automatically.

  The liquid ejecting apparatus includes a plurality of modes having different resolutions of dots formed by ejecting the liquid, and the error check selection unit performs the error check according to a designated mode among the plurality of modes. It is preferable to select whether to enable or disable error checking.

  According to this configuration, whether the error check by the error check unit is enabled or disabled is selected by the error check selection unit according to the mode in which the dot resolution is different. Therefore, the user does not have to perform an operation for selecting whether to enable or disable the check.

  A liquid ejection method that solves the above problem is a liquid ejection method in which a head drive circuit controls a plurality of ejection units based on a drive signal and an integrated control signal transmitted by a control unit via a flexible cable and ejects liquid. A selection step for selecting whether to enable or disable error check related to liquid ejection, and integrated control in which the control unit controls application and non-application of the drive signal to the plurality of ejection units. A transmission step for transmitting a signal and the drive signal, and an error check for performing an error check of the integrated control signal that is not performed when the head drive circuit is disabled when the error check is enabled. And a plurality of ejection control systems to which the integrated control signal is distributed when the error check result is at least an error. It includes a control step for controlling the plurality of the discharge portion based on the signal and the driving signal. According to this method, it is possible to obtain the same effect as that of the liquid ejecting apparatus.

1 is a schematic perspective view of a printer according to a first embodiment. The schematic diagram which shows schematic structure of a head unit and a circuit board. The schematic diagram which shows the nozzle opening surface of a discharge head, and a drive element. (A) is a schematic diagram which shows selection data, (b) is a schematic diagram which shows printing control data. The figure which shows a drive signal, a latch signal, a channel signal, and print control data. 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. The schematic diagram explaining the translation rule of a decoder. 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. (A) shows signal waveforms, such as a printing control signal at the time of normality, (b) is a figure which shows signal waveforms, such as a printing control signal at the time of abnormality. (A) is a schematic diagram which shows the verification data and selection data at the time of normality, (b) is a schematic diagram which shows the verification data and selection data at the time of abnormality. 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. 9 is a block diagram showing an electrical configuration of an erroneous ejection determination system and an ejection control system in a head drive circuit in a second embodiment. (A) is a timing chart explaining the discharge control at the time of normal determination, (b) is a timing chart explaining the discharge control by the data complement at the time of error determination. 6 is a flowchart showing a signal input sequence in the head drive circuit.

(First embodiment)
Hereinafter, a first embodiment in which a liquid ejecting apparatus, a head unit, and a liquid ejecting method are embodied 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 has 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. A carriage 15 is supported on the guide member 14 in a state where the carriage 15 can reciprocate in the scanning direction X. The carriage 15 is provided with a discharge head 16 at a position where it can face the support base 13. A plurality (four in this embodiment) of liquid containers 17 that store ink, which is an example of liquid, are detachably mounted on the carriage 15.

  As an example, the four liquid containers 17 contain black (K), cyan (C), magenta (M), and yellow (Y) ink. The ink supplied from each liquid container 17 is ejected toward the paper P from the ejection head 16 moving in the scanning direction X together with the carriage 15, so that color printing is possible.

  A driving pulley 18 and a driven pulley 19 are rotatably supported at both ends of the frame 12 at a predetermined distance in the scanning direction X. 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 reciprocates in the scanning direction X while being guided by the guide member 14.

  Further, the printer 11 is provided with a transport motor 22 and various rollers that are rotated by a driving force from the transport motor 22. Then, each roller rotates by driving the transport motor 22, so that the paper P is transported on the support base 13 in the transport direction Y that is a direction intersecting (preferably orthogonal) with the scanning direction X.

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

  Next, a configuration for 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 is provided with a circuit board 30 fixed to the frame 12 and a head drive circuit 61 provided on the ejection head 16. The head drive circuit 61 is a circuit for controlling the drive of a plurality of drive elements 62 provided for each nozzle in the ejection head 16. The head driving circuit 61 constitutes a head unit 60 together with the ejection head 16. As the drive element, for example, a piezoelectric vibrator or an electrostatic drive element can be used.

  The circuit board 30 is electrically connected to the head driving circuit 61 via the flexible cable 65. The flexible cable 65 is a long cable so as not to hinder the movement of the carriage 15. Therefore, when the flexible cable 65 is deformed as the carriage 15 moves, the flexible cable 65 may come into contact with the frame 12 or other components in the frame 12. And static electricity etc. generate | occur | produce at the time of this kind of contact or deformation | transformation of a flexible cable, and this may become a noise source. There are various other noise sources.

  The circuit board 30 is provided with a controller 31 as 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”. In such a controller 31, various data and signals for controlling the driving of the drive element 62 of the ejection head 16 are generated, and these various data and signals are used as the data line DL and the signal lines SL1 and SL1 constituting the flexible cable 65. The data is transferred (output) to the head drive circuit 61 through SL2, SL3, SL4, and the like. The head driving circuit 61 selectively outputs a driving pulse corresponding to the input data for each driving element 62, whereby ink is selectively ejected from each nozzle corresponding to each driving element 62, and the paper P On the other hand, images, characters, etc. are printed based on the print data.

  The data transferred using the data line DL includes print data SI, which is an example of dot formation data, and selection data SP. That is, in the present embodiment, the data line DL is a signal line for inputting both the print data SI and the selection data SP from the controller 31 to the head drive circuit 61. The signals transferred using the signal lines SL1 to SL4 include a drive signal COM, a latch signal LAT, a channel signal CH, and a clock signal SCK. Details of these data and each signal will be described later. In FIG. 2, only one data line DL is shown, but in the present embodiment, a plurality of data lines DL (for example, four lines) are provided in the same number as the number of ink colors. Print data SI and selection data SP for each color are transferred in parallel through DL. In the present embodiment, the selection data SP corresponds to an example of a check reference signal and an example of a selection signal.

  Next, the discharge head 16 will be described with reference to FIG. As shown in FIG. 3, the nozzle opening surface 161 which is the bottom surface of the discharge head 16 is indicated by # 1 to # 360 arranged in a line at a constant nozzle pitch in the transport direction Y which is the vertical direction in the drawing. For example, a plurality of (four in the example of FIG. 3) nozzle arrays each formed by a total of 360 nozzles 162 are formed. 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 is the same arrangement pattern as the nozzle row. However, in FIG. 3, the drive element 62 is schematically drawn outside the ejection head 16. The pair of nozzles 162 and the drive elements 62 constitute a discharge unit 63. For example, the ejection head 16 is provided with an ejection unit group 64 including 360 ejection units 63 corresponding to the nozzles 162 indicated by # 1 to # 360 per nozzle row. In the present embodiment, one ejection unit 63 in the ejection unit group 64 corresponds to an example of a “first ejection unit”, and the other one ejection unit 63 corresponds to an example of a “second ejection unit”. To do.

  Next, various signals used when driving the drive element 62 of the ejection head 16, 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 drive signal COM is generated in time series in a plurality of (four in the present embodiment) drive pulses (four in the present embodiment) during the printing cycle TA secured to form one dot. Waveform). That is, the drive signal COM is a signal 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. Note that the first drive pulse DP1 is a pulse having a large amplitude in the first period T1. The second drive pulse DP2 is a pulse for finely vibrating the ink in the nozzle when there is no dot (no ink droplet ejection), and is a pulse in the second period T2. The third drive pulse DP3 is a pulse with a large amplitude in the third period T3, and the fourth drive pulse DP4 is a medium amplitude pulse in the fourth period T4.

  As shown in FIG. 5, the latch signal LAT is a signal for defining the start timing of the drive signal COM, that is, the timing at which the first drive pulse DP1 of the drive signal COM is generated. That is, the latch signal LAT includes a pulse generated at the start timing of the drive signal COM.

  As shown in FIG. 5, the channel signal CH is a signal that defines the timing of switching from the previous drive pulse to the next drive pulse in one drive signal COM. That is, the channel signal CH is a pulse generated at a timing when the first driving pulse DP1 is switched to the second driving pulse DP2, a pulse generated at a timing when the second driving pulse DP2 is switched to the third driving pulse DP3, and a third driving pulse. It includes a pulse generated at the timing of switching from DP3 to the fourth drive pulse DP4.

  As shown in FIG. 5, the controller 31 includes black print control data SIn (K), cyan print control data SIn (C), magenta print control data SIn (M), and yellow print control data SIn (Y). Are transferred in parallel to the head drive circuit 61 through the flexible cable 65 in synchronization with the clock signal SCK. In the following description, when the colors are not particularly distinguished, they are simply referred to as “print control data SIn”. In the present embodiment, the print control data SIn corresponds to an example of an “integrated control signal”.

  The print control data SIn verifies the print data SI used by the discharge unit 63 for one nozzle row for one discharge and the presence or absence of a data shift error, which will be described later, caused by nozzles in the transfer process through the flexible cable 65. And verification data CP used for (checking). The controller 31 transmits selection data SP and print control data SIn (print data SI and verification data CP) in synchronization with the clock signal SCK. At this time, the controller 31 first outputs selection data SP at the start of printing. Next, the controller 31 outputs print control data SIn (print data SI and verification data CP) for one nozzle row within the print cycle TA, and thereafter repeats output of the print control data SIn every print cycle TA. Specifically, as shown in FIG. 5, black print data SI (K) and its verification data CP, cyan print data SI (C) and its verification data CP, magenta print data SI (M) and its verification data The CP and yellow print data SI (Y) and the verification data CP are transmitted in parallel within the print cycle TA in synchronization with the clock signal SCK. The selection data SP is output every time the program pattern needs to be changed, and is output at least at the start of the print job. Therefore, in this embodiment, the selection data SP and the print control data SIn are transmitted when the selection data SP is changed, and the print control data SIn is transmitted after the selection data SP is changed. In the present embodiment, the verification data CP corresponds to an example of a “checked signal”.

  Next, the selection data SP, print data SI, and verification data CP will be described with reference to FIG. The selection data SP shown in FIG. 4A is data for selecting the driving mode of each driving element 62. As shown in FIG. 5, the selection data SP includes information on the fourth drive pulse DP4 (4 bits), information on the third drive pulse DP3 (4 bits), information on the second drive pulse DP2 (4 bits), and The information (4 bits) of the first drive pulse DP1 is included. That is, the selection data SP is data for selecting a drive pulse (waveform) from the drive signal COM.

  The print data SI shown in FIG. 4B is data that defines the size of the ink dots formed on the paper P by the drive of the drive element 62. Such print data SI is 2-bit data per dot (1 nozzle), and is composed of gradation information representing four gradations including no dots (non-recording), small dots, medium dots, and large dots. . As shown in FIG. 5, the print data SI is upper bit data “SIH” (360 bits) consisting only of upper bits for 360 nozzles of the gradation information “HL” for 360 nozzles (one nozzle row). And lower bit data “SIL” (360 bits) consisting only of lower bits for 360 nozzles.

  Next, the electrical configuration of the printer 11 will be described with reference to FIG. 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 configured by a CPU, a RAM 42 that temporarily stores various data, and a nonvolatile memory 43 that stores various programs. The main control unit 41 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. In place of the display unit 26, when a data shift error of the print control data SIn occurs, a lamp such as an LED that can be notified by lighting or blinking may be used.

  The ASIC 33 shown in FIG. 6 includes 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, print data SI, selection data SP, and the like. And a data output control unit 47 for outputting.

  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. Print data SI as image data for printing that is serially transferred to the ejection head 16 is developed in the output buffer 42C, which is also an image buffer.

  The main control unit 41 shown in FIG. 6 includes a discharge control signal generation unit 411 and an error check selection unit 412. The discharge control signal generation unit 411 reads and analyzes the print data in the input buffer 42A, and develops the print data SI into a plurality of bits with reference to font data, graphic functions, and the like in the nonvolatile memory 43. The expanded print data SI is stored in the output buffer 42C, and when the print data SI corresponding to one line of the ejection head 16 is obtained, the print data SI for one line is output to the data output control unit 47. Is done. In the present embodiment, the discharge control signal generation unit 411 corresponds to an example of a “control signal generation unit”.

  The printer 11 has an error check function for checking data in order to determine erroneous ejection of the ejection head 16 before ejection. The printer 11 is provided with a first mode (erroneous ejection determination mode) that enables the error check function and a second mode that disables the error check function. For example, the user operates the operation unit 25 to select one of the first mode and the second mode. The error check selection unit 412 in the controller 31 stores one mode selected from the first mode and the second mode in the memory based on the operation signal from the operation unit 25. If the mode to be stored is the first mode, the error check selection unit 412 transmits a check instruction signal for instructing an error check to the head drive circuit 61, while if it is the second mode, the error check selection unit 412 checks the head drive circuit 61. Send unnecessary signals.

The main control unit 41 instructs the drive signal generation circuit 46 to output the latch signal LAT and the channel signal CH to the head drive circuit 61.
A drive signal generation circuit 46 shown in FIG. 6 generates a drive signal COM, a latch signal LAT, and a channel signal CH based on an instruction (trigger signal) from the main control unit 41, and outputs these signals COM, LAT, and CH to the head. Output to the drive circuit 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. Further, the drive signal generation circuit 46 generates a pulse of the latch signal LAT at the start timing of the drive signal COM, and generates a pulse of the channel signal CH at a timing at which the previous drive pulse is switched to the next drive pulse in one drive signal COM. Occur. 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 outputs the data trigger DT to the data output control unit 47.

  The data output control unit 47 selects the selection data SP (program pattern data) read from the nonvolatile memory 43, the print data SI read from the output buffer 42C, and the verification data CP (signal value) having the same data value (signal value) as the selection data SP. Program pattern data) is output in synchronization with the clock signal SCK from the oscillation circuit 45. Here, the selection data SP is output once prior to the output of the print data SI at the start of printing. For example, a value corresponding to the print mode is set in the selection data SP, so that the selection data SP having a value corresponding to the next print mode is output once at least at the timing when the print mode changes. For this reason, at the start of a print job, selection data SP corresponding to the print mode specified in the print job is transmitted from the data output control unit 47 to the head drive circuit 61 through the flexible cable 65.

  Here, in the printer 11 of the present embodiment, a high-quality print mode (for example, a photo print mode) that prioritizes print quality (quality) over print speed (productivity) and a print speed prioritize over print quality. A plurality of printing modes including a high-speed printing mode (for example, a draft printing mode) is prepared. The nonvolatile memory 43 stores a plurality of selection data SP corresponding to a plurality of printing modes. The controller 31 reads one selection data SP corresponding to a designated print mode from the nonvolatile memory 43 at the start of printing, and outputs the read selection data SP to the head drive circuit 61 prior to output of the print control data SIn. When using a maintenance-specific drive pulse that is different from the drive pulse at the time of flushing (empty ejection) for ejecting ink droplets not related to printing, selection data to be changed at the start of flushing is output, The original selection data SP is output after the flushing is completed.

  Further, the data output control unit 47 serially transfers (outputs) the print data SI to the head drive circuit 61 through the flexible cable 65 for each nozzle row. Further, when the data trigger DT is input, the data output control unit 47 serially transfers (outputs) the verification data CP to the head driving circuit 61 through the flexible cable 65 after the print data SI for each nozzle row. . The data output control unit 47 outputs selection data SP, print data SI, and verification data CP in synchronization with the clock signal SCK. The data output control unit 47 includes, for example, a counter, counts, for example, the number of pulses of the clock signal SCK at the time of data output, and terminates data output when the counted value reaches a predetermined value for each data type. . For this reason, the main control unit 41 can know from the notification from the data output control unit 47 that the output of the print data SI and the verification data CP for one nozzle row has been completed. Check the error port 35a of F35. An error signal (for example, H level) is input to the error port 35a when a determination result of the later-described erroneous ejection determination performed in the head drive circuit 61 is an error.

  As shown in FIG. 6, the head drive circuit 61 is prepared for each type of ink (here, for each color), that is, for each nozzle row, and each head drive circuit 61 includes a control circuit 70, a receiver 71, and an SCK counter. 72, a data sorting unit 73, an error check unit 74, and a discharge control unit 75. The ejection control unit 75 ejects ink from the ejection head 16 by controlling each driving element 62. In the present embodiment, the discharge control unit 75 constitutes an example of a “discharge control signal distribution unit”.

  Selection data SP and serial data including print data SI and verification data CP for one column are sequentially input from the data output control unit 47 to the receiving unit 71. Then, the receiving unit 71 outputs the input serial data to the data sorting unit 73. The selection data SP is basically input once when it is necessary to change the program pattern.

  The clock signal SCK transmitted from the controller 31 is input to the SCK counter 72. The SCK counter 72 counts the number of pulses of the input clock signal SCK, and outputs the number of pulses Pclk, which is the counting result, to the data partition unit 73.

  For example, the selection data SP is input to the data classification unit 73 at the start of a print job (at the start of printing), and the print control data SIn for one column is input in the first communication following this. The data sorting unit 73 outputs the first input selection data SP to the error check unit 74. Further, the data division unit 73 divides the print control data SIn inputted in the first and subsequent communications into two lines, that is, print data SI for one line and verification data CP based on the number of pulses Pclk from the SCK counter 72. The print data SI is output to the ejection control unit 75 and the verification data CP is output to the error check unit 74.

  The error check unit 74 illustrated in FIG. 6 includes a first storage unit 741, a second storage unit 742, a comparison circuit 743, and a determination circuit 744. The error check unit 74 compares the selection data SP input from the data classification unit 73 at the start of printing with the verification data CP acquired in the first and subsequent communications, thereby causing the erroneous discharge in the print control data SIn. Check for transmission errors such as noise.

The first storage unit 741 stores verification data CP received in the first and subsequent times. The verification data CP is changed each time the next verification data CP is received.
The second storage unit 742 stores selection data SP received at the start of printing. The selection data SP is held in the second storage unit 742 until it is changed for reasons such as changing the print mode.

  The comparison circuit 743 compares whether the verification data CP input from the first storage unit 741 matches the selection data SP input from the second storage unit 742, and outputs a match signal to the determination circuit 744 if they match. When there is a mismatch, a mismatch signal is output to the determination circuit 744.

  The determination circuit 744 determines the presence or absence of an erroneous ejection error based on the match signal or the mismatch signal input from the comparison circuit 743. Specifically, when the coincidence signal is input, the determination circuit 744 determines that there is no erroneous ejection error and outputs a normal signal (for example, L level) as the determination signal JS. On the other hand, the determination circuit 744 determines that there is an erroneous ejection error when a mismatch signal is input, and outputs an error signal ES (for example, H level) as the determination signal JS.

The discharge control unit 75 illustrated in FIG. 6 includes a print data storage unit 751, a selection signal generation unit 752, and a gate driver circuit 753.
The print data storage unit 751 receives the print data SI from the data sorting unit 73 and the clock signal SCK and the latch signal LAT from the controller 31. When the pulse of the latch signal LAT is input, the print data storage unit 751 latches the print data SI. Then, the print data SI latched in the print data storage unit 751 is output to the gate driver circuit 753.

  The selection signal generator 752 receives the selection data SP from the second storage unit 742 of the error check unit 74 and the latch signal LAT and the channel signal CH from the controller 31. That is, the selection signal generation unit 752 generates a pulse selection signal based on the input selection data SP, latch signal LAT, and channel signal CH, and outputs this pulse selection signal to the gate driver circuit 753.

  The gate driver circuit 753 receives print data SI from the print data storage unit 751, a pulse selection signal from the selection signal generation unit 752, and a drive signal COM from the controller 31. The gate driver circuit 753 ejects ink by driving the drive element 62 based on these various signals. That is, the gate driver circuit 753 determines the driving mode of the driving element 62 based on the pulse selection signal based on the selection data SP, the print data SI, and the driving signal COM, and controls the driving element 62 based on the determined driving mode. By doing so, ink is ejected from the ejection head 16.

  Next, specific configurations of the print data storage unit 751, the selection signal 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 portions corresponding to the drive elements 62A and 62B for the two nozzles constituting one nozzle row are shown.

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

  In the print data storage unit 751A, the upper bit data “H” of the print data SI (2-bit data) for the drive element 62A is input to the first shift register 81, and the drive data 62A is used. The lower bit data “L” of the print data SI is input to the second shift register 82. Similarly, in the print data storage unit 751B, the upper bit data “H” of the print data SI for the drive element 62B is input to the first shift register 81, and the print data SI for the drive element 62B The lower bit data “L” is input to the second shift register 82.

  A first latch circuit 83 is electrically connected to the first shift register 81. A second latch circuit 84 is electrically connected to the second shift register 82. When the latch signal LAT is input to the latch circuits 83 and 84, the first latch circuit 83 latches the upper bit data “H” of the first shift register 81. The second latch circuit 84 latches the lower bit data “L” of the second shift register 82. In this way, the print data storage units 751A and 751B can temporarily store the print data SI before being input to the decoder 86 described later.

  As illustrated in FIG. 7, the selection signal generation unit 752 includes a third shift register 85A and a logic circuit 85B. The selection data SP is input to the third shift register 85A. The logic circuit 85B receives the selection data SP, the latch signal LAT, and the channel signal CH from the third shift register 85A. Then, the logic circuit 85B generates decode data that the decoder 86 uses for the decoding process based on the selection data SP, and outputs the decode data to each decoder 86 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 86, a level shifter 87, and a switch circuit 88. The decoder 86 receives the upper bit data “H” from the first latch circuit 83, the lower bit data “L” from the second latch circuit 84, and the pulse selection signal from the selection signal generator 752 described above. Then, the decoder 86 generates pulse selection information based on the various types of input data and signals, and outputs the pulse selection information to the level shifter 87.

  The level shifter 87 is inputted with the pulse selection information from the decoder 86 every time the timing specified by the timing signal comes in order from the upper bits. For example, at the start of the period T1 which is the first timing (see FIG. 5), the most significant bit data of the pulse selection information is input, and at the start of the period T2 which is the second timing, the pulse selection information The data of the second bit in is input. Such a level shifter 87 functions as a voltage amplifier. When the pulse selection information is “1”, the level shifter 87 outputs an electric signal boosted to a voltage capable of driving the switch circuit 88, for example, a voltage of about several tens of volts. The pulse selection information “1” boosted by the level shifter 87 in this way is input to the switch circuit 88.

A drive signal COM from the controller 31 is input to the input side of the switch circuit 88. Further, driving elements 62A and 62B are connected to the output side of the switch circuit 88.
Then, by controlling the operation of the switch circuit 88 based on the pulse selection information, the first to fourth drive pulses DP1 to DP4 are selectively supplied to the drive elements 62A and 62B. For example, during the period when the pulse selection information applied to the switch circuit 88 is “1”, the switch circuit 88 is turned on, and the drive pulse at that time is supplied to the drive element 62. The potential level of 62B changes. On the other hand, while the pulse selection information applied to the switch circuit 88 is “0 (zero)”, the level shifter 87 does not output an electrical signal for operating the switch circuit 88. For this reason, the switch circuit 88 is disconnected and no drive pulse is supplied to the drive elements 62A and 62B.

  Next, the pulse selection information generated by the decoder 86 will be described with reference to FIG. As shown in FIG. 8, 2-bit print data SI (HL) for each nozzle is translated by the decoder 86 into pulse selection information PS composed of 4-bit data (D1, D2, D3, D4). “D1” is a selection signal for the first drive pulse DP1, “D2” is a selection signal for the second drive pulse DP2, “D3” is a selection signal for the third drive pulse DP3, and “D4” is the first signal. This is a selection signal for the four drive pulses DP4. The 4-bit pulse selection information PS is given to the switch circuit 88 corresponding to each nozzle.

  That is, print data SI of 2 bits per nozzle for all nozzles (360 nozzles) is set in the first and second shift registers 81 and 82, and each of the first and second latches is received by the next latch signal LAT. Latched by the circuits 83 and 84. The print data SI input from the latch circuits 83 and 84 to the decoder 86 is referred to by the decoder 86 by referring to the pulse selection signal input at a timing synchronized with the latch signal LAT or the channel signal CH. Translated into pulse selection information. A selection signal is output from the decoder 86 to the switch circuit 88 through the level shifter 87 at a timing synchronized with the drive pulse. That is, when the generation of the first drive pulse DP1 is detected by the latch signal LAT, the data “D1” is output for each nozzle, and when the generation of the second drive pulse DP2 is detected by the next channel signal CH, Data “D2” is output for each nozzle.

  As described above, when four-step dot gradation is performed, a combination of print data (gradation value) and drive pulse can be freely set by using the selection data SP corresponding to the truth table shown in FIG. Is possible. At this time, every time print data SI for one nozzle row is output, 16-bit selection data SP is output subsequently. This selection data SP is data that defines the relationship between the print data SI and the selected drive pulses DP1 to DP4. For example, in the example shown in FIG. 8, 16-bit data consisting of [0100101000011100] (also FIG. 4). Reference). Here, the selection data SP is composed of 4-bit information for each drive pulse, and the 4-bit information of the fourth drive pulse DP4, the third drive pulse DP3, the second drive pulse DP2, and the first drive pulse DP1 is sequentially displayed. Is transmitted. The selection data SP is 4 bits per drive pulse arranged in order from the upper bit side in the order of print data “11” “10” “01” “00” (that is, large, medium, small, fine vibration). Information.

  Therefore, as shown in FIG. 8, the selection data SP includes the fourth drive pulse “0100”, the third drive pulse “1010”, the second drive pulse “0001”, and the first drive pulse “1100”. It is sent in order and becomes information consisting of 16 bits of [0100101000011100].

  Based on the selection data SP, pulse selection information corresponding to each print data SI (HL) is obtained as a truth table shown in FIG. That is, the print data “00” is obtained corresponding to the pulse selection information (0100), and the print data “01” is obtained corresponding to the pulse selection information (0010). The print data “10” is obtained in correspondence with the pulse selection information (1001), and the print data “11” is obtained in correspondence with the pulse selection information (1010). The most significant bit of the pulse selection information corresponds to the first drive pulse DP1, the second bit corresponds to the second drive pulse DP2, the third bit corresponds to the third drive pulse DP3, and the least significant bit. Corresponds to the fourth drive pulse DP4. As described above, the selection data SP is data indicating a correspondence relationship between the print data SI (HL) and at least one selected from the four drive pulses DP1 to DP4.

  The decoder 86 outputs pulse selection information (D1, D2, D3, D4) corresponding to the print data SI (HL) in synchronization with the corresponding four drive pulses DP1 to DP4. The switch circuit 88 selects supply or non-supply of each drive pulse to the drive element 62 according to the value “0” or “1” of each bit input in a boosted state from the decoder 86 via the level shifter 87. To do. When the most significant bit of the pulse selection information is “1”, the switch circuit 88 is connected in the period T1, and when the second bit is “1”, the switch circuit 88 is in the period T2. Connected. Further, when the third bit is “1”, the switch circuit 88 is connected in the period T3, and when the least significant bit is “1”, the switch circuit 88 is connected in the period T4. . When the bit value is “0”, the switch circuit 88 is not connected during that period.

  That is, based on the small dot print data “01”, the corresponding drive element 62 is supplied with the fourth drive pulse DP4. Further, the first drive pulse DP1 and the fourth drive pulse DP4 are supplied to the corresponding drive element 62 based on the medium dot print data “10”. Further, the first drive pulse DP1 and the third drive pulse DP3 are supplied to the corresponding drive element 62 based on the large dot print data “11”. Further, based on the print data “00” of the minute vibration, the corresponding drive element 62 is supplied with the second drive pulse DP2.

  Therefore, as shown in FIG. 8, in the case of “large dots” of the print data “11”, the first drive pulse DP1 and the third drive pulse DP3 are selected, and two large ink droplets are ejected. Large dots are formed on the paper P. In the case of “medium dot” of the print data “10”, the first drive pulse DP1 and the fourth drive pulse DP4 are selected, and the medium P is ejected on the paper P by ejecting large and small ink droplets one by one. Dots are formed. Further, in the case of “small dots” of the print data “01”, the fourth drive pulse DP4 is selected, and small dots are formed on the paper P by ejecting one small ink droplet. In the case of “fine vibration” of the print data “00”, the second drive pulse DP2 is selected, and the ink in the nozzle is slightly vibrated to suppress ink thickening when there is no dot that does not eject ink. It is done. This suppresses subsequent ink ejection defects.

  Next, a specific configuration of the head drive circuit 61 will be described with reference to FIG. As shown in FIG. 9, the error check unit 74 includes a first register 91. The first register 91 stores print control data SIn for one column. The first register 91 includes a first storage unit 741 that stores selection data SP, and a print data storage unit 745 that stores print data SI. That is, the first storage unit 741 of this example is configured by a partial storage area of the first register 91 in which the print control data SIn is stored.

  The control circuit 70 receives the clock signal SCK received from the controller 31, the mode selection signal MS, and the like. The control circuit 70 controls the first register 91 by the control signal AS, and transfers the selection data SP received at the start of printing and stored in the first register 91 to the second storage unit 742. The second storage unit 742 includes a second register 92 having a storage capacity capable of storing the selection data SP.

  The print control data SIn received in the first and subsequent communications is stored in the first register 91, but the control circuit 70 controls the first register 91 by the control signal AS and stores it in the first storage unit 741. The verified data CP is output to the comparison circuit 743. Further, the control circuit 70 controls the second register 92 by the control signal BS and outputs the selection data SP stored therein to the comparison circuit 743. As described above, the comparison circuit 743 compares the current verification data CP input from the first storage unit 741 with the selection data SP input from the second storage unit 742, and indicates a signal (match signal or Discrepancy signal) is output to the determination circuit 744. Then, as described above, the determination circuit 744 determines the presence or absence of an erroneous ejection error based on the signal from the comparison circuit 743, and outputs a determination signal JS indicating the determination result. In the present embodiment, the determination signal JS output from the comparison circuit 743 is output from the head drive circuit 61 to the controller 31 through the flexible cable 65.

  The first register 91 is connected to the third register 94 via the selector 93 so that data can be transmitted. Similar to the first register 91, the third register 94 has a storage capacity capable of storing one column of print control data SIn. Whenever the print control data SIn is stored in the first register 91, the control circuit 70 controls the selector 93 by the control signal CS. First, the print data SI from the first register 91 (print data storage unit 745) is transferred to the third register 91. Transfer to register 94. As soon as this transfer is completed, the control circuit 70 switches the selector 93, reads the selection data SP from the second storage unit 742, and transfers it to the third register 94. In this way, the print data SI and the selection data SP of this time are stored in the third register 94 as a set each time. At this time, the selection data SP is stored in the third storage unit 754 of the third register 94. 6 includes a part of the functions of the first register 91 and the selector 93 controlled by the control circuit 70. 9 includes a first shift register 81 and a second shift register 82 in the example of FIG. 7, and the third storage unit 754 in FIG. 9 is the first shift register 81 in the example of FIG. 3 shift registers 85A.

  Thereafter, the control circuit 70 shown in FIG. 9 controls the third register 94 by the control signal DS and transfers the selection data SP from the third storage unit 754 to the selection signal generation unit 752. The selection signal generation unit 752 is configured by, for example, a logic circuit 85B shown in FIG. Each decoder 86 outputs to the level shifter 87 pulse selection information PS (see FIG. 8) generated by decoding the input print data SI (HL) based on the decode data.

Next, an erroneous ejection determination process performed in the first mode will be described with reference to FIGS.
As shown in FIG. 10A, the print control signal SIn (print control data SIn) and the clock signal SCK are transferred in parallel from the controller 31 to the head drive circuit 61 through the flexible cable 65 at the same timing. The print control signal SIn is a pulse signal including a large number of pulses having an H level of “1” and an L level of “0”, and the head driving circuit 61 reads a certain section of the clock signal SCK as data. In the example of FIG. 10A, the input to the head drive circuit 61 is “10101...” By reading the print control signal SIn.

  By the way, the process in which the print control signal SIn is transmitted through the flexible cable 65 is because the flexible cable 65 is relatively long, the movement during scanning is relatively fast, and static electricity that becomes a noise source is easily generated. , SCK is relatively easy to get noise. As shown in FIG. 10B, when noise N is added to the signals SIn and SCK being transmitted, the head drive circuit 61 reads the noise N as data “111”. For this reason, the input to the head drive circuit 61 is “11110101...”. In this case, the number of data based on the print control signal SIn read as noise “111” (three in the example in the figure). Just shift.

  As shown in FIG. 11A, when normal without noise, the verification data CP “0100101000011100” stored in the first storage unit 741 is selected as the selection data SP “0100101000011100” stored in the second storage unit 742. (SP = CP). Therefore, the comparison circuit 743 outputs a coincidence signal, and the determination circuit 744 that has received the coincidence signal outputs an H-level determination signal JS (normal signal NS).

  On the other hand, as shown in FIG. 11B, the verification data CP “1110100101000011” stored in the first storage unit 741 is stored in the second storage unit 742 at the time of abnormality with noise. The selected data SP does not coincide with “0100101000011100” (SP ≠ CP). Therefore, the comparison circuit 743 outputs a mismatch signal, and the determination circuit 744 that has received the mismatch signal outputs an L level determination signal JS (error signal ES).

  Next, the operation of the printer 11 will be described with reference to FIGS. Before starting printing, the user operates the operation unit 25 to determine whether the first mode (erroneous ejection judgment mode) for enabling the erroneous ejection judgment function or the second mode (normal mode) for invalidating the erroneous ejection judgment function. Select by. The error check selection unit 412 writes the selected mode based on the operation signal from the operation unit 25 in a memory such as the RAM 42. The mode is set by turning on / off a flag, for example. Further, instead of the method by the operation of the operation unit 25, the computer 32 enables or disables the erroneous ejection determination function according to at least one item among the printing conditions including the printing mode and the paper type (medium type). The structure which selects whether to do may be sufficient. For example, the error check selection unit 412 selects the first mode when the print mode is a high-quality print mode (for example, photo print mode) in which print quality (quality) is given priority over print speed (productivity), and printing is performed. The second mode may be selected when it is a high-speed printing mode (for example, draft printing mode) that prioritizes printing speed over quality. Further, the error check selection unit 412 may select the first mode when the medium type is the first medium type for photographic printing and the second mode when the medium type is the second medium type including plain paper. In the present embodiment, the process in which the computer 32 selects the first mode or the second mode based on the operation signal or the printing condition information corresponds to an example of “selection step”.

  When printing is started, a drive signal and a signal such as 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. 12, 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, in step S11, it is determined whether or not printing is started. If it is time to start printing, the process proceeds to step S12. On the other hand, for example, if printing is in progress and the time when printing is not started, the process proceeds to step S13.

  In step S12, selection data SP is output. The controller 31 reads the selection data SP corresponding to the print mode designated in the received print job from the nonvolatile memory 43 and transmits it to the head unit 60. Further, the controller 31 writes the selection data SP in a memory such as the RAM 42.

  In the next step S13, print data SI is output. The controller 31 generates print data SI that can be used by the head drive circuit 61 from print data in the print job, and transmits the print data SI in synchronization with the clock signal SCK.

  In the next step S14, verification data CP is output. The controller 31 reads the selection data SP from the memory and outputs it to the head drive circuit 61 as verification data CP. At this time, the verification data CP is output in synchronization with the clock signal SCK.

  In step S15, it is determined whether or not the output of one data SI and CP has been completed. The controller 31 counts the number of pulses of the clock signal SCK synchronized with the data SI and SP with a counter (not shown) at the time of output, and the counted value reaches a predetermined value corresponding to the data length of the data SI and SP. It is determined that the output has been completed. If the output is not completed, the process returns to step S13, the output of the print data SI (S13) or the output of the verification data CP (S14) is continued, and when the output of the data SI and CP for one time is completed (Yes in S15), Proceed to step S16.

  In step S16, it is determined whether or not the erroneous ejection determination mode (first mode) is set. The controller 31 proceeds to step S17 if the currently selected mode read from the memory is the first mode, and ends the sequence if it is the second mode (normal mode).

  In step S17, the error port is confirmed. If the error port 35a is at a signal level indicating that there is no error (for example, L level), the controller 31 ends the sequence. On the other hand, if the error port 35a is at a signal level (for example, H level) indicating that there is an error, the process proceeds to step S18.

  In step S18, error processing is performed. That is, the controller 31 causes the display unit 26 to display a message indicating that an erroneous ejection has occurred. Accordingly, the user can know that a printing defect (printing error) due to erroneous ejection of ink droplets has occurred in the printed matter. Note that the error processing may be a notification of the occurrence of erroneous ejection by lighting or blinking of an LED or warning light, or by a buzzer or sound by a speaker. The error process is a print stop process in which the controller 31 instructs the head drive circuit 61 to stop printing, or printing of a mark (mark) indicating an erroneous discharge occurrence position (defect position) in an unnecessary margin of the paper P. It may be a mark printing instruction process to instruct, or a process of displaying an illustration or a message indicating the position of the defect on the display unit 26.

  In this way, the controller 31 performs the printing instructed by the print job by repeatedly executing the signal output sequence shown in FIG. 12 for each ejection control cycle. In the erroneous ejection determination mode, the error port 35a is sequentially checked during printing, and error processing is performed if an error is notified from the head unit 60 side. In the present embodiment, the processes in steps S13 and S14 correspond to an example of a “transmission step”.

On the other hand, on the head unit 60 side, the following signal input sequence shown in FIG.
First, in step S21, selection data SP is input. The selection data SP input by the receiving unit 71 is stored in the second storage unit 742 in the error check unit 74 via the data sorting unit 73.

In the next step S22, print data SI is input. The print data SI input by the receiving unit 71 is stored in the print data storage unit 751 via the data sorting unit 73.
In step S23, verification data CP is input. The verification data CP input by the receiving unit 71 is stored in the first storage unit 741 in the error check unit 74 via the data sorting unit 73. In this way, the head drive circuit 61 ends the input of the selection data SP sent at the start of printing and the first print control data SIn (print data SI and verification data CP) sent subsequently.

In the next step S24, it is determined whether or not it is an erroneous ejection determination mode. If it is the erroneous ejection determination mode, the process proceeds to step S25, and if it is not the erroneous ejection determination mode, the process proceeds to step S27.
In step S25, the selection data SP is compared with the verification data CP. That is, the comparison circuit 743 compares whether the verification data CP input from the first storage unit 741 matches the selection data SP input from the second storage unit 742. The comparison circuit 743 outputs a coincidence signal (for example, an L level signal) if the selection data SP and the verification data CP match, and outputs a mismatch signal (for example, an H level signal) if they do not coincide.

  In the next step S26, it is determined whether or not the selection data SP and the verification data CP match (SP = CP). This determination process is performed by the determination circuit 744. The determination circuit 744 proceeds to step S27 if a coincidence signal indicating that SP = CP is input from the comparison circuit 743, and proceeds to step S28 if a disagreement signal indicating that SP ≠ CP is input.

  In step S27, discharge control based on the print data SI is performed. That is, the gate driver circuit 753 drives the drive element 62 based on the current print data SI input from the print data storage unit 751 and ejects ink droplets from the nozzles 162. In this way, printing for one time (one printing cycle TA) is performed by the ejection head 16. In the present embodiment, the process of step S27 corresponds to an example of a “control step”.

  In step S28, an error signal is output. When the mismatch circuit is input from the comparison circuit 743, the determination circuit 744 outputs an error signal ES (for example, an H level signal) as the determination signal JS. The error signal ES is transmitted to the controller 31 through the flexible cable 65, for example. The controller 31 confirms the error port 35a, and if the error port 35a is at the signal level (for example, H level) of the error signal ES, for example, a message indicating that an erroneous ejection has occurred is displayed on the display unit 26 as error processing ( Equivalent to S17 and S18 in FIG. 12). In the present embodiment, the processes in steps S25, S26, and S28 correspond to an example of an “error check step”.

  Thereafter, by repeatedly executing the processes of steps S22 to S28, the second and subsequent printing control data SIn are sequentially input, and the erroneous ejection determination based on the comparison between the selection data SP and the verification data CP is performed, and the printing is performed. Discharge control based on the data SI is performed. When an erroneous ejection occurs, an error signal ES is transmitted to the controller 31 side, and this is displayed on the display unit 26 as a message.

  As a result, the user can know that an erroneous ejection has occurred during printing. For example, when it is a printed matter of an important document such as a contract or a printed matter such as a photograph or a poster that requires a high print quality, the user displays a message that an erroneous ejection has occurred during printing with the first mode selected. When it is done, the completed printed matter is checked, and if necessary, reprinting is performed.

According to the first embodiment described in detail above, the following effects can be obtained.
(1) A first mode (erroneous ejection determination mode) in which the erroneous ejection determination function is enabled and a second mode (normal mode) in which the erroneous ejection determination function is disabled can be selected. Therefore, for example, when printing a printed matter in which the print image quality is particularly important, such as a contract or a photograph for a product, the user selects the first mode by operating the operation unit 25, for example. The discharge determination can be performed. When an erroneous discharge occurs during printing, a message to that effect is displayed on the display unit 26, so that the user can know that there is a possibility of a printing defect due to the erroneous discharge in the printed matter. . Therefore, the user can check whether the print quality of the finished printed matter is within the allowable range, and can perform reprinting if necessary. As a result, it becomes easier to avoid a situation where a printed matter in which erroneous ejection has occurred is used as a contract or a product without being checked as it is. On the other hand, when the erroneous ejection determination function is not necessary, for example, when it is not an important printed matter, the user can eliminate unnecessary or undesired error processing by selecting the second mode.

  (2) In the case of a printed matter that does not matter the print image quality, the second mode (normal mode) is selected. When performing erroneous ejection determination, it is necessary to finish the determination process by the determination circuit 744 before the next ejection timing arrives. For this reason, in a high-speed printing model or the like, the time required for the determination process may be longer than the time until the next ejection timing arrives. Needs to be relatively slow. In this case, the productivity of the printed matter is lowered due to the slow printing speed. However, in this embodiment, in addition to the first mode in which the erroneous ejection determination function is enabled, the second mode in which the erroneous ejection determination function is disabled can be selected. Therefore, if the second mode is selected, the printed material can be printed at high speed. It can meet the needs of productivity. Therefore, according to the printer 11 of the present embodiment, it is possible to cope with both a specification that prioritizes productivity and a specification that prioritizes quality in accordance with user needs.

  (3) The error check selection unit 412 included in the controller 31 selects whether the error check by the error check unit 74 is to be valid or invalid. When the error check is valid, the error check unit 74 on the head drive circuit 61 side performs an error check on the print control data SIn. If the check is invalidated, the error check unit 74 does not check the print control data SIn for errors. Therefore, an error check can be selected when high quality is required for a printed material (an example of a liquid droplet discharge formed product) formed by discharging ink droplets, and an error check can be selected when high quality is not required. For example, if the error check is selected to be invalidated, the error check waiting time is eliminated, leading to an increase in the printing processing speed of the printer 11.

  (4) The controller 31 first transmits selection data SP (an example of a reference signal for checking) to the head unit 60 at the start of printing, and then transmits print control data SIn to the head unit 60. Therefore, the error check unit 74 can check the print control data SIn for errors by comparing the verification data CP in the current print control data SIn with the selection data SP stored in the second storage unit 742. it can.

  (5) The error check selection unit 412 selects whether to enable or disable the error check in the error check unit 74 based on the operation signal from the operation unit 25 operated by the user. For this reason, the user can select execution / non-execution of erroneous ejection determination according to needs. Therefore, for example, the validity or invalidity of the error check that the user does not want, which may occur in the configuration in which the validity or invalidity of the check is automatically selected, is arbitrarily selected, and the error processing that is not desired is performed or desired. Inconveniences such as error processing not being implemented can be avoided.

  (6) The printer 11 includes a plurality of print modes (an example of modes) having different print resolutions. When the error check selection unit 412 is configured to select whether to enable or disable the error check according to the designated print mode among the plurality of print modes, the user enables the error check. It is not necessary to operate the operation unit 25 for selecting whether or not to invalidate.

  (7) The discharge control signal generation unit 411 includes the print data SI (an example of the discharge control signal) and at least one drive pulse to be applied to the discharge unit 63 (drive element 62) among the plurality of drive pulses DP1 to DP4. Selection data SP indicating the correspondence is acquired. The selection data SP is used as a reference signal for checking. For this reason, it is not necessary to prepare a reference signal dedicated to checking that is not used for discharge control. Further, since the selection data SP can be used for both ejection control and error check, for example, transmission of print control data SIn by transmitting an extra signal (data) not related to ejection control, such as a reference signal dedicated to checking. A delay in the start time can be avoided.

  (8) The print control data SIn includes verification data CP (an example of a signal to be checked) having the same content as the selection data SP. For this reason, the error check unit 74 can check the print control data SIn by comparing the selection data SP and the verification data CP. In addition, since the verification data CP has the same content as the selection data SP, it is possible to perform discharge control using the verification data CP instead of the selection data SP when it is not an error determination.

  (9) Since the message indicating that there is an error in the erroneous ejection determination is displayed on the display unit 26, it is possible that the printed matter may include a printing defect due to erroneous ejection of ink droplets due to noise N. Can be notified. Therefore, the frequency at which the user does not notice a printing defect included in the printed matter can be reduced.

(10) When the process for interrupting printing is performed as error processing, wasteful ink consumption due to continuation of printing after error determination can be suppressed.
(Second Embodiment)
Next, a second embodiment will be described with reference to FIGS. In the first embodiment, in the first mode (erroneous ejection determination mode), when it is determined that there is an erroneous ejection, the ink droplet is allowed to be erroneously ejected and printing is continued as it is, and the user is informed that an erroneous ejection has occurred. Stayed in. In contrast, the present embodiment has a correction function for correcting the current print data SI, which has been determined as an error, and continuing printing when it is determined that an erroneous ejection has occurred in the first mode. In the following, only the differences from the first embodiment will be described.

  In the present embodiment, the first mode is an erroneous ejection correction mode that enables the erroneous ejection preventing function, and the second mode is a normal mode that invalidates the erroneous ejection preventing function. Before starting printing, the user sets the first mode for enabling the erroneous ejection prevention function or the second mode for invalidating the erroneous ejection prevention function by operating the operation unit 25. The main control unit 41 writes the set mode in a memory such as the RAM 42.

  As shown in FIG. 14, in the first mode, the gate driver circuit 753 is configured to read each 2-bit print data SI in which the print data SI for the current nozzle row, which has been determined as an error, is distributed for each drive element 62 is a decoder. A discharge control circuit 95 that corrects the pulse selection information PS output via 86 and a correction control circuit 96 that controls the discharge control circuit 95 are provided. In this example, the current pulse selection information PS after the decoding of the current print data SI including the data shift error due to noise or the like generated in the transmission process of the flexible cable 65 is transmitted to the previous time of the normal transmission. Of these, correction is performed by replacing the pulse selection information PS after decoding of the print data SI of the latest time (for example, the previous time). The ejection control circuit 95 stores the pulse selection information PS after decoding the previous print data SI in the storage unit. If the current print control data SIn is an error, the previous pulse selection information PS stored in the storage unit is stored. Is output as the current pulse selection information PS. In the present embodiment, the ejection control circuit 95 and the correction control circuit 96 constitute an example of a “correction unit”.

  Next, the detailed configuration of the discharge control circuit 95 will be described with reference to FIG. As shown in FIG. 14, the discharge control circuit 95 is provided between the decoder 86 and the switch circuit 88. The ejection control circuit 95 includes an AND circuit 101 having one input terminal connected to the output terminal of the decoder 86 and an N register 102 having an input terminal connected to the output terminal of the AND circuit 101. Further, the discharge control circuit 95 includes an AND circuit 103 having one input terminal connected to the output terminal of the N register 102, and a B register 104 having an input terminal connected to the output terminal of the AND circuit 103. Yes. The discharge control circuit 95 includes an AND circuit 105 having one input terminal connected to the output terminal of the N register 102, and an AND circuit 106 having one input terminal connected to the output terminal of the B register 104; It has. The control signals NC and BC from the correction control circuit 96 are input to the other input terminals of the two upstream AND circuits 101 and 103. That is, the current pulse selection information PS output from the decoder 86 and the control signal NC are input to the AND circuit 101, and the output of the N register 102 and the control signal BC are input to the AND circuit 103. Further, the output from the N register 102 and the selection signal NJ are input to the AND circuit 105, and the output of the B register 104 and the selection signal BJ are input to the AND circuit 106. The output terminals of the AND circuits 105 and 106 are connected to the input terminal of the level shifter 87.

  The N register 102 stores the pulse selection information PS after decoding the 2-bit print data SI distributed for each drive element 62 out of the current print data SI for one nozzle row. The B register 104 stores pulse selection information PS after decoding the 2-bit print data SI distributed for each drive element 62 out of the previous print data SI for one nozzle per row. In the present embodiment, the B register 104 corresponds to an example of a “storage unit” provided in the correction unit. Further, in the present embodiment, a plurality of B registers 104 as an example of a storage unit for each ejection unit 63 are stored in the previous value BR for each ejection unit 63 as an example of a first ejection control signal and a second ejection control signal. This is an example of storing (pulse selection information PS).

  The correction control circuit 96 outputs an H level control signal NC and an H level control signal BC at the time of normality determination when the determination signal JS indicating normality is input from the determination circuit 744. For this reason, when normal, the current pulse selection information PS stored in the N register 102 is transferred to the B register 104 as the previous pulse selection information PS, and the output of the decoder 86 is used as the current pulse selection information PS in the N register. 102.

  Further, the correction control circuit 96 outputs an H level selection signal NJ and an L level selection signal BJ. As a result, the current pulse selection information PS stored in the N register 102 is output from the AND circuit 105. The current pulse selection information PS output from the ejection control circuit 95 is output to the switch circuit 88 via the level shifter 87.

  Further, the correction control circuit 96 outputs an H level control signal NC and an L level control signal BC when an error determination is made by inputting the error signal ES from the determination circuit 744. For this reason, the current pulse selection information PS stored in the N register 102 is not transferred to the B register 104. At this time, the output of the decoder 86 is stored in the N register 102 as the current pulse selection information PS.

  Further, at the time of error determination, the correction control circuit 96 outputs an L level selection signal NJ and an H level selection signal BJ. As a result, the previous pulse selection information PS stored in the B register 104 is output from the AND circuit 106. Thus, the previous pulse selection information PS output from the ejection control circuit 95 is output to the switch circuit 88 via the level shifter 87. At this time, the current pulse selection information PS including the error stored in the N register 102 is not output from the AND circuit 105.

  Therefore, at the time of normality determination, the current pulse selection information PS is output from the ejection control circuit 95, and the drive pulse selected based on the current pulse selection information PS is applied to the drive element 62. As a result, an ink droplet having a size based on the current print data SI is ejected from the nozzle 162. At the time of error determination, the previous pulse selection information PS is output from the ejection control circuit 95, and the drive pulse selected based on the previous pulse selection information PS is applied to the drive element 62. As a result, ink droplets of the same size as the previous time are ejected from the same nozzle 162 as the previous time based on the previous print data SI. Therefore, at the time of error determination, the same printing (ink ejection) as the previous time is repeated by each of the ejection units 63, so that the printed line is printed with little discomfort to the extent that the printed line becomes somewhat thicker or thinner.

  Next, the operation of the discharge control circuit 95 controlled by the correction control circuit 96 will be described with reference to FIG. In FIG. 15, for the sake of simplicity, an example in which the number of drive pulses composing the drive signal COM is three is shown, and the waveform of the drive pulse is also drawn with a trapezoidal waveform. The first driving pulse DP1 and the third driving pulse DP3 having a large waveform are ejection driving pulses for ejecting ink droplets when applied to the driving element 62, and the second driving pulse DP2 is applied to the driving element 62. Is also a drive pulse for fine vibration that vibrates to the extent that it does not lead to ejection. FIG. 15 shows an example in which non-ejection (print data SI = “00”) continues for the first two times of the printing cycle TA, and the third ejection (print data SI = “11”). . In FIG. 15, the current pulse selection information PS is represented as “current value NR”, and the previous pulse selection information PS is represented as “previous value BR”. Further, since the pulse selection information PS is information defining selection / non-selection for the three drive pulses DP1 to DP3, the current value NR and the previous value BR are, for example, 3-bit values.

  As shown in FIG. 15A, when the determination circuit 744 is normal, the determination signal JS becomes H level every time (three times in the figure) every printing cycle TA. When an H level determination signal JS is input, the correction control circuit 96, as shown in FIG. 15A, both H level control signals NC and BC, and an H level selection signal NJ (not shown), An L level selection signal BJ (not shown) is output. Therefore, the current value NR that has been stored in the N register 102 in the discharge control circuit 95 shown in FIG. 14 until then is transferred to the B register 104 as the previous value BR when the control signal BC is at the H level. At the same time, the output of the decoder 86 is sequentially stored in the N register 102 bit by bit as the current value NR when the control signal NC is at the H level. Further, the current value NR stored in the N register 102 is sequentially output from the AND circuit 105 bit by bit. The current value NR output from the discharge control circuit 95 in this way is input to the switch circuit 88 via the level shifter 87. As a result, the drive pulse selected based on the current value NR is applied to the drive element 62.

  In the example of FIG. 15A, since the current value NR is (010) in the first and second printing cycles TA, the first and third drive pulses DP1 and DP3 are not applied to the drive element 62 and are not ejected (see FIG. 15). In FIG. 15A, the mark becomes “x”, and when the second drive pulse DP2 is applied to the drive element 62, the drive element 62 slightly vibrates (“−” mark in FIG. 15A). Therefore, in the first and second printing cycles TA, the drive element 62 slightly vibrates with such strength that it does not eject ink droplets. As a result, the ink in the nozzle 162 is agitated, so that the nozzle 162 is prevented from being clogged due to thickening of the ink. In the second printing cycle TA, the first current value NR = (010) is transferred to the B register 104 as the previous value BR.

  In the example shown in FIG. 15A, since the current value NR = (101) is output from the correction control circuit 96 in the third printing cycle TA, the first and third drive pulses DP1 and DP3 are driven. An ink droplet is ejected from the nozzle 162 by being applied to the element 62 (“◯” in FIG. 15A), and the second drive pulse DP 2 is not applied to the drive element 62. As a result, a large ink droplet is ejected from the nozzle 162. In the third printing cycle TA, the B register 104 stores the second current value NR = (010) as the previous value BR.

  On the other hand, as shown in FIG. 15B, when the determination circuit 744 makes an error determination in the second printing cycle TA, the determination signal JS becomes an L-level error signal ES. At this time, as shown in FIG. 15B, the current value NR for the second time when an error has occurred becomes an incorrect value due to a data shift error caused by the noise N. When the present value NR in the indefinite state is selected, ink droplets are not ejected from the nozzles 162 that should be ejected, ink droplets are ejected from the nozzles 162 that should not be ejected, or originally ejected from the nozzles 162. Incorrect ejection may occur, in which an ink droplet having a droplet size different from the intended droplet size is ejected. As a result, a printing defect is formed by the dots landed by erroneously ejected ink droplets.

  However, in this embodiment, at the time of this error determination, the correction control circuit 96 gives both the H level control signals NC and BC and the L level selection signal NJ (not shown) as shown in FIG. And an H-level selection signal BJ (not shown) are output. Therefore, the current value NR that has been stored in the N register 102 in the discharge control circuit 95 shown in FIG. 14 until then is transferred to the B register 104 as the previous value BR when the control signal BC is at the H level. At the same time, every time the control signal NC becomes H level, the output of the decoder 86 is stored bit by bit in the N register 102. The current value NR in an indefinite state stored in the N register 102 is the discharge control circuit 95. The previous value BR stored in the B register 104 is output from the discharge control circuit 95. As a result, the drive pulse based on the previous value BR is selected.

  In the example of FIG. 15B, since the previous value BR is (010) in the second printing cycle TA, the first and third drive pulses DP1 and DP3 are not applied to the drive element 62 and are not ejected (FIG. 15). In FIG. 15B, “x” marks), and the drive element 62 slightly vibrates when the second drive pulse DP2 is applied (“−” marks in FIG. 15B). That is, at the time of error determination, the same discharge control as the previous time is performed based on the previous value BR.

  For example, when an ink droplet is ejected from the nozzle 162 last time, an ink droplet having the same droplet size as the previous one is ejected from the same nozzle 162 as the previous time based on the previous value BR at the time of error determination. Therefore, at the time of error determination, each ejection unit 63 performs the same printing (ink ejection) twice, so that the printed line is slightly thicker or thinner and the print is not so uncomfortable. . In the B register 104, the current value NR = (010) for the first time is stored as the previous value BR.

  Then, as shown in FIG. 15B, in the next third printing cycle TA, the correction control circuit 96 outputs an H level control signal NC, an L level control signal BC, and an H level selection signal. NJ (not shown) and an L level selection signal BJ (not shown) are output. For this reason, the current value NR in an indefinite state that has been stored in the N register 102 until then is not transferred to the B register 104 as the previous value BR. As a result, the B register 104 is held at the previous value. On the other hand, every time the control signal NC becomes H level, the output of the decoder 86 is stored bit by bit in the N register 102, so that the current value NR of the error stored so far is the next new current value NR = It is rewritten as (101).

  The current value NR = (101) stored in the N register 102 is output from the ejection control circuit 95. Therefore, the first and third drive pulses DP1 and DP3 are applied to the drive element 62 (“◯” in FIG. 15B), and the second drive pulse DP2 is not applied to the drive element 62 (FIG. 15B). Then “-” sign). As a result, a large ink droplet is ejected from the nozzle 162.

  Even if the error determination is continued a plurality of times, the discharge control circuit 95 outputs a normal previous value and does not output the current value NR in an indefinite state. As a result, the same discharge control as the previous time is performed based on the previous time value. Therefore, even if the error determination is continued a plurality of times, the same printing (ink ejection) is repeated by each ejection unit 63 a number of times the error is continued, so the printed lines are somewhat thicker or thinner. Although it is printed, it is printed without a sense of incongruity.

  Next, the operation of the printer 11 of this embodiment will be described. When the controller 31 receives the print job, the controller 31 transmits a mode selection signal MS for notifying the mode selected from the first mode and the second mode to the head drive circuit 61. The mode selection signal MS received by the head drive circuit 61 is input to the control circuit 70. And the controller 31 performs the signal output sequence shown with the flowchart in FIG. 12 similarly to 1st Embodiment. Further, the head drive circuit 61 of this embodiment executes the signal input sequence shown in the flowchart of FIG. Hereinafter, the signal input sequence will be described.

  First, in step S31, selection data SP is input. The selection data SP input by the receiving unit 71 is stored in the second storage unit 742 in the error check unit 74 via the data sorting unit 73.

  In step S32, the print data SI is input and held until the next discharge timing. The print data SI input by the receiving unit 71 is stored in the print data storage unit 751 via the data sorting unit 73. Further, the data is distributed to 2-bit data corresponding to each nozzle 162 in the gate driver circuit 753 and stored in each N register 102. Each N register 102 stores the pulse selection information PS after the print data is decoded.

  In step S33, verification data CP is input. The verification data CP input by the receiving unit 71 is stored in the first storage unit 741 in the error check unit 74 via the data sorting unit 73. Thus, the head drive circuit 61 finishes the input of the selection data SP at the start of printing and the first print control data SIn.

In step S34, it is determined whether or not it is an erroneous ejection determination mode. If it is the erroneous ejection determination mode, the process proceeds to step S35, and if it is not the erroneous ejection determination mode, the process proceeds to step S37.
In step S35, the selection data SP is compared with the verification data CP. That is, the control circuit 70 outputs the control signals AS and BS to control the data output destinations of the first storage unit 741 and the second storage unit 742, and the verification data CP and the second storage in the first storage unit 741. Both the selection data SP in the unit 742 are sent to the comparison circuit 743. The comparison circuit 743 compares the verification data CP input from the first storage unit 741 with the selection data SP input from the second storage unit 742. If the two match, the comparison circuit 743 determines a match signal (for example, an L level signal). If there is a mismatch, a mismatch signal (eg, an H level signal) is output to the determination circuit 744.

  In step S36, it is determined whether or not the selection data SP and the verification data CP match (SP = CP is established). This determination process is performed by the determination circuit 744. The determination circuit 744 proceeds to step S37 if a coincidence signal indicating that SP = CP is established, and proceeds to step S38 if a disagreement signal indicating that SP ≠ CP is input.

  In step S37, ejection control based on the current print data SI is performed. That is, the gate driver circuit 753 drives the drive element 62 based on the current print data SI input from the print data storage unit 751 and ejects ink droplets from the nozzles 162. In this way, normal printing (one printing cycle TA) is performed by the ejection head 16.

  In the normal state, the correction control circuit 96 outputs an H level selection signal NJ and an L level selection signal BJ. As a result, at this normal time, the current value NR stored in the N register 102 is output to the switch circuit 88 via the level shifter 87.

  Therefore, at the normal time, the current value NR is output to the switch circuit 88 via the level shifter 87, and the drive pulse selected based on the current value NR is applied to the drive element 62. As a result, an ink droplet having a size based on the current value NR is ejected from the nozzle 162.

  In the normal state, the correction control circuit 96 outputs an H level control signal NC and an H level control signal BC. For this reason, the current value NR stored in the N register 102 is transferred to the B register 104 as the previous value BR, and the output of the decoder 86 is stored in the N register 102 as the current value NR.

  In step S38, discharge control based on the previous print data SI is performed. That is, the correction control circuit 96 that has received the error signal ES from the determination circuit outputs an H level control signal NC, an L level control signal BC, an L level selection signal NJ, and an H level selection signal BJ. To do. As a result, the previous value BR stored in the B register 104 is output from the discharge control circuit 95 to the switch circuit 88 via the level shifter 87. Therefore, the drive pulse selected based on the previous value NR is applied to the drive element 62. As a result, ink droplets of a size based on the previous value BR are ejected from the nozzle 162, and the same printing as the previous time is performed. For this reason, the printed line is printed so that the printed line becomes somewhat thicker or thinner, and does not feel uncomfortable. Further, the current value NR in an indefinite state stored in the N register 102 is not moved to the B register 104. For this reason, the previous value BR until then is held in the B register 104. For example, even if the error determination is repeated a plurality of times, the previous value BR stored in the B register 104 can be output.

  At the time of error determination, an error signal ES indicating an error is transmitted from the correction control circuit 96 to the controller 31 as a determination signal JS. When the controller 31 receives the error signal ES, the controller 31 executes error processing similar to that in the first embodiment. The controller 31 causes the display unit 26 to display a message indicating the occurrence of erroneous ejection. Accordingly, the user can know that a printing defect (printing error) due to erroneous ejection of ink droplets has occurred in the printed matter. However, in this example, since the correction is performed by replacing the current value NR in an indefinite state with the previous value BR, the degree of defects is extremely small. In addition, the error processing may be notification of the occurrence of erroneous ejection by lighting or blinking of an LED or warning light, or by a buzzer or sound by a speaker. Alternatively, mark printing instruction processing for instructing printing of a mark indicating the position of a defect due to erroneous ejection in an unnecessary margin of the paper P, or display of an illustration or a message indicating the position of the defect on the display unit 26 may be used.

  According to the second embodiment described above in detail, the erroneous ejection determination process is the same as that in the first embodiment, and therefore the same effects (1) to (9) as in the first embodiment except for the effect of correction at the time of error determination. In addition, the following effects can be further obtained.

  (11) The discharge control unit 75 (an example of a discharge control signal distribution unit) includes a discharge control circuit 95 (an example of a correction unit) that corrects the current print control data SIn that has caused an error in the check of the error check unit 74. . The current print control data SIn that has become an error by the check of the error check unit 74 is corrected by the discharge control circuit 95. Therefore, compared to the case where ink droplets are ejected with the current print control data SIn including an error, ink droplets are ejected using the current print control data SIn after correction, thereby giving an example of a printed matter (an example of a liquid ejection formation). ) Can improve the quality.

  (12) The ejection control circuit 95 includes a B register 104 (an example of a storage unit) that stores print data SI (an example of the first and second ejection control signals), and if the error check result is an error, The previous print data SI stored in the B register 104 is set as the current print data SI. The print data SI of this time and the previous time are likely to be similar in the arrangement of the ejection positions from which the ink droplets of the ejection unit group 64 are ejected. For example, the line formed by the dots of the ejected ink droplets becomes thicker. Since the print data SI becomes thin, it is possible to reduce the degree of quality degradation of the printed matter compared to the case where printing is performed using the current print data SI in which an error has occurred.

  (13) A first mode (erroneous ejection prevention mode) that enables the erroneous ejection prevention function and a second mode (normal mode) that invalidates the erroneous ejection prevention function can be selected. Therefore, in the case of printing in which the print image quality is particularly important, such as a contract or a product photo, the user selects the first mode by operating the operation unit, thereby performing the misdischarge prevention control on the printer 11 during printing. Make it. Even if a data shift occurs in the print control data SIn due to noise generated in the flexible cable 65 and an error occurs in the selection data SP, the drive element 62 is driven with the corrected print data SI once (one print). Printing of period TA) can be performed. In particular, in this example, since the drive element 62 is driven using the previous print data SI (pulse selection information PS), there is no great discomfort to the extent that the printed line is somewhat thicker or thinner. Therefore, it is possible to obtain a printed matter with high print quality as compared with the case of erroneous ejection.

  (14) In the case of a printed matter in which the print image quality is not important, by selecting the second mode (normal mode), printing can be performed at a higher speed than in the first mode (erroneous ejection prevention mode). In addition to the first mode for enabling the erroneous ejection preventing function, the user can also select the second mode for invalidating the erroneous ejection preventing function. Therefore, by selecting the second mode, it is possible to print at a relatively high speed and obtain a desired printed matter at an early stage.

  (15) Since a message indicating that the correction by the erroneous ejection preventing function has been performed is displayed on the display unit 26, the user is informed that printing dots printed with the print data SI corrected to prevent erroneous ejection are included. Can know.

In addition, the said embodiment can also be changed into the following forms.
In each of the embodiments described above, the count process for counting the clock signal SCK from the controller 31 on the head unit 60 side is performed. However, the count process may not be performed. In this case, the operation of the comparison circuit 743 that compares the selection data SP and the verification data CP can be controlled by an external signal. For example, the mode selection signal MS shown in FIG. 9 is output every time data SI and CP are transferred, and the head unit 60 side compares the mode selection signal MS with the selection data SP and the verification data CP. 743 is used for timing control to operate. Specifically, the controller 31 outputs a mode selection signal MS that temporarily becomes H level at the timing of transferring the data SI and CP once and becomes L level at other timings. The control circuit 70 in the head drive circuit 61 starts the operation of the comparison circuit 743 and the like in the erroneous ejection determination mode at the timing when the mode selection signal MS changes from the L level to the H level. The control circuit 70 may start the operation of the comparison circuit 743 and the like in the erroneous ejection determination mode at the timing when the mode selection signal MS changes from the H level to the L level. According to these configurations, the execution timing of erroneous ejection determination by the comparison circuit 743 and the determination circuit 744 can be delayed as much as possible within a determinable range, and the influence of noise generated before the transfer of the data SI and CP can be reduced. The discharge accuracy can be improved by eliminating as much as possible.

  In each of the embodiments, the verification data CP as an example of the checked signal is not limited to the same data value as the selection data SP. The verification data CP may have the same signal value as a part of the selection data SP. For example, in the case of 16-bit selection data, half of the selection data for 8 bits is used as verification data, and 2 bits or 3 bits of data for further selection data is used as verification data. Also good. In short, the verification data has a maximum data shift amount (shift number) assumed when a data shift caused by noise occurs, or a predetermined margin (for example, a predetermined value within a range of 1 to 3 bits) in the maximum data shift amount. It is preferable to set the number of added bits. If the verification data CP having a bit number smaller than the bit number of the selection data SP is used as described above, the print control data SIn can be transferred at a high speed by the amount of the data amount of the print control data SIn, and the error check unit. The load of the check process in 74 is reduced, and the time required for the check process is shortened. For example, even if the first mode is selected, the degree of decrease in the printing speed can be suppressed smaller than when the second mode is selected. As described above, when the verification data CP (an example of a signal to be checked) is a part of the selection data SP, the signal length (data) of the print control data SIn is larger than when the verification data CP is the entire selection data SP. Size) can be shortened. Therefore, the print control data SIn can be transmitted to the head unit 60 side at a higher speed (shorter time) as much as the signal length can be shortened. Therefore, for example, the printing process (an example of the liquid discharge process) can be speeded up.

  The check reference signal does not use at least a part of the selected data, and may be a check-specific reference signal (reference data). In this case, when the selection data SP is transmitted, a reference signal exclusively for checking is transmitted to the head drive circuit 61, and the verification data CP having the same contents as the reference data is head-driven following the print data in the first and subsequent communications. Transmit to the circuit 61. According to this configuration, transmission of the reference signal dedicated to the check becomes unnecessary, but if the number of verification data transmitted after the print data SI is shortened, the transfer speed of the print control data SIn can be increased.

  The correction is performed by replacing the current value NR in an indeterminate state with the previous value BR at the time of error determination, but the correction processing by the correction unit may be other processing. For example, the correction may be made so that the droplet size (dot size) to be discharged is smaller than the maximum size. Further, all the ejection portions may be corrected to print data in which ejection and non-ejection are mixed. Even in these cases, it is possible to reduce the degree of printing defects as compared to erroneous ejection in which liquid is ejected at the maximum size from all ejection sections.

  In the embodiment, the discharge control unit 75 performs discharge control using the selection data SP stored in the second storage unit. However, in the case of normal determination, the discharge control unit 75 performs discharge control using the verification data CP. You may go. In this case, in the case of error determination, ejection control is performed using the selection data SP of the second storage unit 742. According to this configuration, when there is no error, the print control data in the first register 91 may be transferred to the third register as it is, and the process of reading the selection data SP from the second storage unit 742, for example, the control circuit 70 selects the selector 93. Since the process of reading the selection data SP by controlling the control can be made unnecessary, the discharge control can be simplified correspondingly.

  In the second embodiment, the previous pulse selection information PS (previous value BR) as an example of the previous ejection control signal is stored in the B register 104 (an example of a storage unit), but an example of the previous ejection control signal As an alternative, the previous print data SI after the distribution of the previous integrated control signal and before decoding may be stored in a storage unit such as a register. Furthermore, print data SI before distribution, which is an example of the previous integrated control signal, may be stored in the storage unit. According to these configurations, at the time of error determination, instead of the current print data SI in the undefined state, the previous print data SI read from the storage unit is output to the decoder 86, so that the current print in the undefined state is performed. Data SI can be corrected.

  When printing is stopped at the time of error determination, printing stop control may be performed without using the controller 31. A determination signal JS (error signal ES) from the determination circuit 744 is output to the gate driver circuit 753 through a transmission path indicated by a two-dot chain line in FIG. 6, and the gate driver circuit 753 stops printing based on the error signal ES. It is good also as a structure which performs control. In this case, for example, it is preferable to display a message indicating that printing has been stopped due to erroneous ejection on the display unit 26 or to notify that the printing has been stopped by turning on or blinking an LED.

  In each of the embodiments, the printing cycle TA is the same in the first mode and the second mode, but a longer time is required for the erroneous ejection determination process (first and second embodiments) and the correction process (second embodiment). May be set longer than the printing cycle TA in the second mode. In this case, if the same printing mode is used, the productivity can be further increased by performing printing at a higher speed in the second mode than in the first mode.

  The first storage unit 741 is configured by a part of the first register 91 in which the print data SI and the verification data CP are stored together. However, the print data SI and the verification data CP are stored in separate registers. Also good.

  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 ejection device may be a line printer having 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. When the first mode is selected, the head drive circuit in the head unit inputs wrong data when data shift occurs due to noise on the flexible cable during transmission of the print control data SIn. The presence / absence of erroneous ejection resulting from the determination is made. On the other hand, when the second mode is selected, the presence / absence of this type of erroneous ejection is not determined. Therefore, according to the user's needs, it is possible to deal with both a specification that prioritizes quality that does not allow printing defects caused by noise and a specification that does not prioritize quality. For example, the line head may be a multi-head type in which a plurality of ejection heads are arranged in a line or zigzag. In this type of multi-head type, the controller is connected to each of a plurality of discharge heads constituting the line head via a flexible cable, or connected to at least one of the plurality of discharge heads via a flexible cable. A configuration may be adopted in which a connection destination ejection head is sequentially connected to an adjacent ejection head. Furthermore, the line head may be configured to be movable such as raising and lowering during cleaning.

  The controller 31 as an example of the control unit is realized by the cooperation of software by a computer executing a program and hardware by an electronic circuit such as an ASIC (Application Specific IC). It may be configured only with.

  -A flexible cable is not limited to a flexible flat cable, What is necessary is just a flexible cable. For example, the controller and the head unit 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 ejecting apparatus is embodied in an ink jet printer (printing apparatus), but is not limited to this. Other fluids other than ink (liquid or liquid material in which particles of functional material are dispersed or mixed in the liquid, It may be a liquid ejecting apparatus that ejects a fluid (such as a gel). For example, even in a liquid ejection device that ejects a liquid material in which a material such as an electrode material or a color material (pixel material) used for manufacturing a liquid crystal display, an EL (electroluminescence) display, and a surface emitting display is dispersed or dissolved. Good. Further, it may be a liquid ejecting apparatus for ejecting a bio-organic material used for biochip manufacturing, or a liquid ejecting apparatus for ejecting a liquid as a sample used as a precision pipette. In addition, a transparent resin liquid such as UV curable resin is used to form a liquid ejection device that ejects lubricating oil pinpoint to precision machines such as watches and cameras, and micro hemispherical lenses (optical lenses) used in optical communication elements. A liquid discharge device that discharges an etching solution 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, 16 ... Discharge head, 162 ... Nozzle, 25 ... Operation part, 26 ... Display part, 31 ... Controller which is an example of a control part, 35a ... Error port, 41 ... Main control part Reference numeral 411: Discharge control signal generator, which is an example of a control signal generator, 412: Error check selector, 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 as an example of the first discharge unit and the second discharge unit, 64 ... Discharge unit group, 65 ... Flexible cable, 74 ... Error check unit, 741 ... First 1 storage unit, 742... Second storage unit as an example of storage unit, 743... Comparison circuit, 744... Judgment circuit, 75 .. discharge control unit as an example of discharge control signal distribution unit, 95 An ejection control circuit as an example of a correction unit, 96... A correction control circuit as an example of a correction unit, 104... B register as an example of a storage unit, SIn, SIn (K), SIn (C), SIn (M), SIn (Y): Print control data as an example of an integrated control signal, COM: Drive signal, SP: Selection data as an example of a reference signal and a selection signal, SI: Print data, CP: Verification as an example of a checked signal Data, DP1, DP2, DP3, DP4... Drive pulse, P... Paper as an example of medium, X... Scanning direction, Y.

Claims (10)

A drive signal generator for generating a drive signal for discharging liquid;
A first discharge section that receives the drive signal and discharges the liquid;
A second ejection unit that ejects the liquid in response to the drive signal;
A discharge unit group including a plurality of discharge units including the first discharge unit and the second discharge unit;
A control signal generation unit that generates an integrated control signal that controls application and non-application of the drive signal to the first and second ejection units;
A discharge control signal distribution unit that distributes the integrated control signal into a first discharge control signal for controlling the first discharge unit and a second discharge control signal for controlling the second discharge unit; ,
An error check unit for performing an error check of the integrated control signal;
A head unit having the ejection unit group, the ejection control signal distribution unit, and the error check unit;
A control unit having the drive signal generation unit and a control signal generation unit;
A flexible cable for electrically connecting the control unit and the head unit;
The liquid ejecting apparatus according to claim 1, wherein the control unit includes an error check selection unit that selects whether the check in the error check unit is valid or invalid.   The liquid ejection apparatus according to claim 1, wherein the ejection control signal distribution unit includes a correction unit that corrects the current integrated control signal in which an error has occurred in the error check unit. The correction unit includes a storage unit that stores the integrated control signal or the first and second ejection control signals,
Correction by using the previous integrated control signal or the previous first and second discharge control signals stored in the storage unit as the current integrated control signal or the current first and second discharge control signals. The liquid ejecting apparatus according to claim 2, wherein: The control unit, after sending a reference signal for checking to the head unit, sends an integrated control signal generated by the control signal generation unit to the head unit,
The integrated control signal includes a checked signal having the same signal value as at least a part of the signal value of the reference signal;
The error check unit
A storage unit for storing the reference signal;
4. The liquid ejection apparatus according to claim 1, wherein an error check is performed based on the checked signal in the integrated control signal and the reference signal stored in the storage unit. 5. The drive signal includes a plurality of drive pulses,
The control signal generation unit further generates a selection signal indicating a correspondence relationship between the ejection control signal and at least one drive pulse to be applied to the ejection unit among the plurality of drive pulses,
The liquid ejecting apparatus according to claim 1, wherein the selection signal is used as the check reference signal. The integrated control signal has a checked signal including the selection signal,
The liquid ejection apparatus according to claim 5, wherein the error check unit performs an error check of the integrated control signal based on the selection signal and the check target signal.   The liquid ejection apparatus according to claim 5, wherein the integrated control signal includes a checked signal that is a part of the selection signal. Provided with an operation unit operated to input instructions,
The error check selection unit selects whether to enable or disable the error check by the error check unit based on an instruction input from the operation unit. The liquid ejection device according to claim 1. It has multiple modes with different resolutions of dots formed by liquid ejection,
The error check selection unit selects whether to enable or disable an error check by the error check unit according to a specified mode among the plurality of modes. The liquid ejection device according to claim 7. A liquid ejection method in which a head drive circuit controls a plurality of ejection units based on a drive signal and an integrated control signal transmitted by a control unit via a flexible cable, and ejects liquid,
A selection step for selecting whether to enable or disable the error check related to liquid ejection; and
A transmission step in which the control unit transmits an integrated control signal for controlling application and non-application of the drive signal to the plurality of ejection units and the drive signal;
An error check step for performing an error check of the integrated control signal that is not performed when the head drive circuit is disabled when the error check is enabled,
A control step for controlling the plurality of ejection units based on the plurality of ejection control signals and the drive signals to which the integrated control signal is distributed, if the error check result is at least an error, and the head drive circuit;
A liquid discharge method comprising: