JP2011161753A - Printing system, maintenance method of printer, and maintenance control program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve such problems that a maintenance is automatically executed each time without exception even when user does not feel the need for the maintenance in a printing system, and the system has been not so easy to handle for user. <P>SOLUTION: In the printing system, the actual measurement value indicating the discharging condition of the ink discharged from a nozzle is measured, and it is determined by using the measurement result which is the ink discharge condition among the three conditions of a normal condition, an unstable discharge condition and a clogging condition. When it is determined that there is a nozzle under the unstable discharge condition, a check image containing a nozzle check pattern used for the visual checking of the generating situation of the unstable discharge condition is printed, and after printing the check image, the user's instruction showing whether the execution of the maintenance for canceling the unstable discharge condition is needed is received, and when the user's instruction shows the need of the execution of the maintenance, the maintenance is executed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a printing system, a printing apparatus maintenance method, and a maintenance control program.

  2. Description of the Related Art Conventionally, a printing apparatus having a function of detecting a discharge state of ink from a nozzle and automatically performing maintenance according to the discharge state is known. In Patent Document 1, an ink discharge state (clogged state or unstable discharge state in which the discharge direction is abnormal) of each nozzle is detected, and in the case of a clogged state, for example, an operation of sucking ink from the nozzle is performed. And other minor maintenance (for example, flushing, small dot ejection, wiping, ink ejection at a low frequency, etc.) that requires less ink consumption than suction in the case of unstable ejection. It is described to do.

JP 2006-175849 A

When there is a clogged nozzle, a so-called dot dropout occurs as a printing result. When there are nozzles in an unstable discharge state, the printed result appears to be lighter than the normal state, for example. However, for example, the fact that the color of the printed result is lighter than the state that should be printed as such is less conspicuous than the occurrence of missing dots, so that it is difficult for the user to recognize. Even if the nozzle inspection performed by the printing device reveals that there are nozzles in an unstable discharge state, the user is unaware of the abnormal image quality or has an acceptable effect on the image quality. Since there may be some cases, even when the user does not feel the need for maintenance, if the maintenance is automatically performed every time without exception, it is not convenient for the user.
An object of the present invention is to reflect a user's intention when maintenance is performed when a nozzle in an unstable discharge state is detected.

  (1) A printing apparatus for achieving the above object includes a measuring unit that measures an actual value indicating the ejection state of ink ejected from a nozzle, and three states: a normal state, an unstable ejection state, and a clogged state Determining means for determining the ink discharge state using the actual measurement value, and if it is determined that there is a nozzle in the unstable discharge state, the occurrence state of the unstable discharge state is visually checked. Check image printing means for printing a check image including a nozzle check pattern used for checking, and after the check image is printed, the user's instruction indicating whether or not maintenance is necessary to eliminate the unstable discharge state A receiving means for accepting and a maintenance means for performing the maintenance when the user's instruction indicates that the maintenance needs to be performed , Comprising a.

  First, in the present specification, the clogged state means a state in which ink droplets are not substantially ejected from the nozzles, and is a state in which so-called dot missing occurs. The unstable ejection state means a state in which ink droplets are ejected from the nozzles but the ink droplet ejection direction is abnormal. For example, the ink droplet is bent without flying perpendicular to the printing surface, or the ink droplet is scattered from a single nozzle in a plurality of directions.

  If it is determined that there is a nozzle in an unstable discharge state, maintenance is automatically performed without exception every time, there is a possibility that the user may feel inconvenience. For example, some users may feel that some image quality degradation due to an abnormal discharge direction is within an acceptable range and they do not feel the need for maintenance. It may be possible to change this. Therefore, even when the influence of the printing result on the image quality due to the presence of unstable ejection nozzles is within the allowable range for the user, if maintenance is always performed without exception, the time required for maintenance and ink Will be consumed unnecessarily against the intention of the user. According to the present invention, when it is determined that there is a nozzle in an unstable discharge state, a check image including a nozzle check pattern is printed, the user is visually confirmed to check the pattern, and the user is determined whether to perform maintenance. You can follow that judgment. As a result, compared to a configuration in which maintenance is always automatically performed without exception when there are nozzles in an unstable ejection state, time and ink consumption can be suppressed, and user requests can be met. .

  (2) In the printing apparatus for achieving the above object, when the maintenance unit determines that the clogged nozzle exists, the maintenance unit automatically performs a suction operation regardless of the user's instruction. Including maintenance may be performed.

When there is a clogged nozzle, the influence on the image quality is greater than when there is an unstable ejection state nozzle. For this reason, the clogging state can be quickly resolved by automatically performing maintenance including suction operation more effective than other maintenance methods to quickly eliminate the clogging state, regardless of the user's judgment. Can contribute.
There are the following assumptions A to C regarding the types and characteristics of maintenance. Maintenance that includes a suction operation requires more time and ink consumption than maintenance that does not include a suction operation (A). On the other hand, the effect of reliably recovering nozzle abnormalities (clogging, unstable discharge) is higher in maintenance including the suction operation than in maintenance not including the suction operation (B). The unstable discharge state may be eliminated by maintenance that does not include a suction operation (C).

  (3) In the printing apparatus for achieving the above object, the measurement of the actual measurement value by the measurement unit is performed when a nozzle check sequence is started, and thereafter repeatedly every time maintenance is performed by the maintenance unit. In the case where it is determined that there is a nozzle in the unstable discharge state, the maintenance is performed N times (N is a natural number) determined in advance by the user's instruction after the nozzle check sequence is started. In the case where the maintenance is already performed N times or more, the check image printing unit prints the check image when the maintenance has been performed N times or more. You don't have to.

  In this case, if the unstable discharge state does not recover even if maintenance is performed N times or more from the start of the nozzle check sequence, the check image printing and visual check are repeated, and maintenance is performed several times. The user can be informed that it has been implemented but will not recover, or that it has failed or that repair or replacement of parts is required.

(4) In the printing apparatus for achieving the above object, when the user's instruction that the maintenance needs to be performed is received after the nozzle check pattern is printed, the maintenance unit first performs the suction operation. maintenance free conducted, the suction maintenance free operation predetermined N ₁ times (N ₁ is a natural number less than said N) nozzles still the unstable discharge condition to implement does not recover to the normal state In some cases, maintenance including the suction operation may be performed.

There are the above-mentioned assumptions A to C regarding the types and characteristics of maintenance. According to the present invention, when there are nozzles in an unstable ejection state, recovery can be attempted with as little ink consumption as possible by performing maintenance that does not include a suction operation. If not recovered be carried out maintenance without the N ₁ times the sucking operation by the ink consumption often it is to perform maintenance including likely suction operation recovery possible recovery of unstable discharge state Can increase the sex.

  (5) In the printing apparatus for achieving the above object, the nozzle check pattern included in the check image includes a dot group formed by ink droplets ejected from the nozzle in the unstable ejection state, and the dot group. The number of nozzles in the unstable ejection state, on the condition that the dot group is configured to include at least a dot group formed by ink droplets ejected from the normal state nozzles. And at least one of the position of the nozzle in the nozzle row including the nozzle in the unstable discharge state and the number of nozzle rows including the nozzle in the unstable discharge state. Good.

  According to the present invention, a check image including a nozzle check pattern that is configured in the same manner every time using every nozzle row or every nozzle in the nozzle row is not printed, and the above condition is satisfied. Thus, a dot group that is not necessary as a nozzle check pattern is not printed. Therefore, since the number of dots printed as a nozzle check pattern can be reduced, the amount of ink consumed for printing the check image can be suppressed. Moreover, since the dot group which does not need as a nozzle check pattern does not exist in a check image after satisfy | filling the said conditions, it can make it easy to visually check the printing result by the nozzle of an unstable discharge state.

(6) In the printing apparatus for achieving the above object, the measurement unit includes a flat plate electrode facing the nozzle array surface in the ink ejection direction, and a flat plate electrode provided on the nozzle array surface. The amount of change in potential associated with the change in capacitance between and may be measured as the measured value indicating the ink ejection state.
The electrostatic capacitance between the plate electrode provided on the nozzle array surface and the plate electrode facing the electrode is the same as when the ink droplet is not ejected from the nozzle and when the ink droplet is ejected from the nozzle. It changes depending on the state until just before leaving. As the capacitance changes, current flows and the potential of the plate electrode changes. In the present invention, by measuring the amount of potential change, it can be used as a material for determining the ink ejection state.

  Note that the function of each means described in the claims is realized by hardware resources whose function is specified by the configuration itself, hardware resources whose function is specified by a program, or a combination thereof. The functions of these means are not limited to those realized by hardware resources that are physically independent of each other. Furthermore, the present invention is also realized as a method for implementing the above contents, a program having the above functions, and a recording medium for recording the program. Of course, the recording medium for the program may be a magnetic recording medium, a magneto-optical recording medium, or any recording medium developed in the future. Further, the order of the operations described in the claims is not limited to the order of description as long as there is no technical obstruction factor, and may be executed at the same time, may be executed in the reverse order of the description order, or may be continuous. It does not have to be executed in order.

1 is a block diagram showing a configuration of a printing system according to a first embodiment. FIG. 3 is a schematic diagram for explaining a moving range of a carriage according to the first embodiment. The schematic diagram which shows the nozzle surface concerning 1st embodiment. The schematic diagram which shows the head and cap concerning 1st embodiment. The schematic diagram which shows the cap concerning 1st embodiment. The figure explaining the structure of the discharge state test | indication concerning 1st embodiment. (7A)-(7C) is a figure which shows the signal used for the discharge state detection concerning 1st embodiment. The figure which shows the relationship between the two threshold values concerning 1st embodiment. The flowchart which shows the nozzle check sequence concerning 1st embodiment. The flowchart which shows the discharge state test | inspection process concerning 1st embodiment. (11A) is a schematic diagram showing a check image to be printed according to the first embodiment, (11B) is an enlarged view showing an example of a printing result of (11A), and (11C) is an overall view of (11B). (12A) is an overall view showing an example of a print result of a check image according to the first embodiment, and (12B) is an overall view showing an example of a print result of a check image according to another embodiment.

  Hereinafter, embodiments of the present invention will be described in the following order with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected to the corresponding component in each figure, and the overlapping description is abbreviate | omitted.

1. 1. First embodiment 1-1. Overview FIG. 1 is a block diagram illustrating a printing system having an inkjet printer 1 (hereinafter simply referred to as a printer) as a printing apparatus and a personal computer (PC) 100. In the present embodiment, the PC 100 and the printer 1 cooperate to inspect the ink ejection state of the nozzles of the printer 1 and automatically perform maintenance according to the ejection state, or perform maintenance according to a user instruction. Implement functions to be implemented.

1-2. Configuration The PC 1 includes a hard disk device (HDD) 110 in which various computer programs such as a printer driver, application program, and OS are stored, a RAM 111 in which these computer programs are loaded, a CPU 112 that executes these computer programs, and a startup program Are stored in the ROM 113, an external interface (I / F) 114 for connecting to an external device, an internal I / F 115 for connecting them, and the like. To the external I / F 114, a mouse 150, a keyboard 151, a display 152, and the printer 1 for operating the PC 1 by a user are connected.

  The printer 1 includes an external I / F 10, a paper transport unit 11, a carriage unit 12, a head unit 13, a discharge state detection unit 15, a cap unit 16, a controller 18, and an internal I / F 9 that connects them. The controller 18 includes a nonvolatile memory for storing firmware and various data, a RAM loaded with the firmware, a CPU for executing the firmware, and the like, and performs overall control in the printer 1. When acquiring the print data from the PC 100, the controller 18 controls the control target unit to print an image on the print medium. The external I / F 10 is an interface for connecting and communicating with other devices, and the controller 18 exchanges data with the PC 100 via the external I / F 10.

  The paper transport unit 11 includes a paper feed roller, a paper feed motor, a motor drive unit, and the like (not shown), and transports the paper in the sub-scanning direction (paper transport direction) as shown in FIG. The carriage unit 12 includes a carriage CR to which the head HD is attached, a carriage motor (not shown), a motor driving unit, and the like, and moves the carriage CR in the main scanning direction (a direction orthogonal to the sheet conveyance direction) as shown in FIG. The carriage CR is provided with a cartridge mounting portion for detachably mounting an ink cartridge (not shown). Each ink cartridge contains different colors of ink.

  The head unit 14 includes a head HD and the like. The head HD is driven by a drive signal output from a drive signal generation circuit (not shown), and discharges ink supplied from an ink cartridge toward a print medium. A number of nozzles Nz for ejecting ink droplets are provided on the paper facing surface of the head HD (the nozzle plate 222 in FIGS. 3 and 4). The nozzle plate 222 is made of a conductive plate-like member (for example, a thin metal plate), connected to the ground line and adjusted to the ground potential, and functions as a flat plate electrode.

  The nozzle group illustrated in FIG. 3 has a plurality of nozzle rows in which the nozzles Nz are provided at a 1/180 inch pitch. Each nozzle row can determine the type of ink to be ejected. In the present embodiment, the head HD is provided with six nozzle rows (NLk, NLy, NLc, NLm, NLlc, NLlm). Each nozzle row is composed of 180 nozzles Nz.

  The cap unit 16 includes a cap 31 (see FIGS. 2 and 4) that forms a space desired by the nozzle Nz group, a wiper 33, a mechanism for moving the cap position with respect to the nozzle surface, and the like. The cap 31 has a rectangular bottom portion and a side wall portion that stands up from the periphery of the bottom portion, and has a thin box shape with the upper surface facing the nozzle plate 222 being open. As shown in FIG. Located in the print area. When the carriage CR moves to the non-printing area, the upper end of the cap 31 is brought into close contact with the nozzle surface to suppress evaporation of the ink solvent from the nozzle Nz.

  A waste liquid tube 314 is connected to the space of the cap 31, and a suction pump (not shown) is connected to the waste liquid tube 314. When the suction pump is operated in a state where the upper opening edge of the cap 31 is in close contact with the nozzle plate 222, ink and air in the head HD can be sucked from the cap 31 side through the nozzle Nz (suction operation). The cap 31 moves relative to the nozzle surface in the non-printing area according to the state of the printer 1. In a flushing operation in which ink droplets are continuously ejected from each nozzle Nz in order to restore the ejection capability of the nozzle Nz, or in an ejection state inspection described later, a slight amount is provided between the nozzle surface and the cap 31 as shown in FIG. It will be in the state which left the clearance gap. At the time of printing operation, it is in a retracted state further away from the nozzle surface than in FIG.

  A sheet-like moisture retention member 312 made of a porous material such as felt or sponge is disposed on the bottom of the cap 31 (see FIG. 5). Ink is landed on the moisture retaining member 312 during the flushing operation or the ejection state inspection. Further, a detection electrode 313 is disposed on the surface of the moisturizing member 312. The detection electrode 313 is used for an ink discharge state inspection described later. The illustrated detection electrode 313 has a double rectangular frame portion, a diagonal line portion connecting the diagonal portions of the rectangular frame portion, and a cross portion connecting the midpoints of the sides of the rectangular frame portion. By this structure, it is uniformly charged over a wide range. Ink is a conductive liquid, and when the detection electrode 313 is set to a high potential while the moisturizing member 312 is moist, the surface of the moisturizing member 312 has the same potential. Therefore, the detection electrode 313 and the moisturizing member 312 function as a flat plate electrode. The wiper 33 is provided near the cap 31 and performs a wiping operation for wiping the nozzle surface (nozzle plate 222) of the head HD.

  Regarding the maintenance method for recovering the discharge capability of the nozzle Nz, there is a fine vibration operation in addition to the suction operation and the flushing operation described above. The fine vibration operation moves the free surface of the ink exposed at the nozzle Nz to the ejection side and the drawing side by giving a pressure change that does not cause ink droplets to be ejected. It is an operation to distribute. Also during the flushing operation, it is possible to change the amount of ink droplets to be ejected (change the size of the dots), change the drive frequency (change the number of ejections per unit time), and the like. Regarding these suction operation, flushing operation, and fine vibration operation, the degree of recovery of the discharge capability of the nozzle Nz is the highest in the suction operation and the lowest in the fine vibration operation. Further, the amount of ink consumed in each operation is the largest in the suction operation and the smallest in the fine vibration operation. Since each maintenance operation has such a difference in characteristics, the printer 1 uses these operations depending on the state. In the present embodiment, it is assumed that the suction operation is performed on all nozzles of the nozzle plate 222, not on a nozzle unit or nozzle row unit basis. The flushing operation and the fine vibration operation may be performed in units of nozzles, in units of nozzle rows, or may be performed for nozzles in all nozzle rows. The wiping operation is performed on the entire nozzle plate 222.

  As shown in FIG. 6, the ejection state detection unit 15 includes a high-voltage power supply unit 41, a resistor 42, a capacitor 44, an amplifier 45, and a detection control unit 47, and detects the ink ejection state of each nozzle Nz. The high-voltage power supply unit 41 is a power supply that brings the detection electrode 313 to a predetermined potential. In the present embodiment, the high-voltage power supply unit 41 is configured by a DC power supply of about 500 V to 600 V, and the operation is controlled by a control signal from the detection control unit 47. One end of the resistor 42 is connected to the output terminal of the high-voltage power supply unit 41, and the other end is connected to the detection electrode 313. The capacitor 44 is an element for extracting a potential change component of the detection electrode 313, and one conductor is connected to the detection electrode 313 and the other conductor is connected to the amplifier 45. The amplifier 45 amplifies and outputs a signal (potential change) appearing at the other end of the capacitor 44. The detection control unit 47 includes a storage unit that stores a determination result for each nozzle Nz, a threshold voltage for determination, an AD conversion unit that converts an amplified analog voltage signal output from the amplifier 45 into a digital value, and the like. The entire discharge state detection unit 15 is controlled.

(Principle of discharge state inspection)
The nozzle plate 222 is connected to the ground so as to have a ground potential, and the detection electrode 313 disposed on the cap 31 is set to a high potential of about 500V to 600V. The nozzle plate 222 and the detection electrode 313 are arranged with a predetermined distance d (see FIG. 6) therebetween, and ink droplets are ejected from the detection target nozzle Nz. The capacitor is formed by arranging the nozzle plate 222 and the detection electrode 313 at a predetermined interval d. As shown in FIG. 6, the ink extending in a columnar shape from the nozzle Nz by contacting the nozzle plate 222 connected to the ground also becomes the ground potential. The presence of such ink is in agreement with locally reducing the electrode spacing of the capacitor and increases the capacitance. As the capacitance increases, the amount of charge that can be stored between the nozzle plate 222 and the detection electrode 313 increases, so that the charge passes from the high-voltage power supply unit 41 to the detection electrode 313 side through the resistor 42 and the like. Move (current I flows toward detection electrode 313). When the current I flows, the potential of the detection electrode 313 changes. The change in the potential of the detection electrode 313 also appears as a change in the potential of the other conductor (conductor on the amplifier 45 side) in the capacitor 44. Accordingly, by monitoring the potential change of the other conductor, it is possible to determine the ink droplet ejection status.

  FIG. 7A is a diagram illustrating the voltage signal SG output from the amplifier 45 when ink is normally ejected from the nozzle Nz. When the drive signal generation circuit generates a drive signal for ejecting ink from one nozzle Nz to be inspected, an ink droplet is ejected from the nozzle Nz. As a result, the voltage signal SG is output from the amplifier 45. The detection control unit 47 compares the potential difference ΔV, which is the difference between the highest voltage VH and the lowest voltage VL of the voltage signal SG, with a threshold value. The potential difference ΔV corresponds to the actually measured value described in the claims.

  In this embodiment, the ink ejection state is classified into the following three states. There are three states: a normal state, an unstable ejection state where ink droplets are ejected from the nozzles but the ink droplet ejection direction is abnormal, and a clogged state where the nozzles are clogged and ink droplets are not ejected. FIG. 7B is a diagram illustrating the voltage signal SG output from the amplifier 45 when an ink droplet is ejected from a nozzle in an unstable ejection state. In an unstable discharge state where ink does not land perpendicularly to the surface of the print medium, the length of the ink droplet immediately before being ejected from the nozzle (from the portion closest to the cap 31 side of the ink droplet to the nozzle plate 222) Is known to be shorter than in the normal state. Therefore, the potential difference ΔV is also smaller than that in the normal state. In the case of a nozzle in an unstable ejection state, the ink landing portion by the nozzle appears to be lighter in color, for example, than the landing portion of a normal nozzle. FIG. 7C is a diagram illustrating a voltage signal SG when an ink droplet is about to be ejected from a clogged nozzle. In a state in which the nozzle is clogged and ink droplets are hardly ejected, such as dot missing, the potential difference ΔV is a smaller value than in the unstable ejection state as shown in FIG. 7C. Therefore, in this embodiment, two threshold values, the first threshold value TH1 and the second threshold value TH2, are used to distinguish the above three states. If the potential difference ΔV is equal to or greater than the first threshold value TH1 (see FIG. 8), it is determined that the ink is normally ejected. If the potential difference ΔV is smaller than the second threshold value TH2, it is determined that the ink is not ejected and is clogged. If the potential difference ΔV is lower than the first threshold TH1 and greater than or equal to the second threshold TH2, it is determined that the unstable ejection state is present.

Since the head HD used in the printer 1 is provided with six nozzle rows NLk to NLlm, 1080 (180 × 6 rows) nozzles Nz are inspected in one ejection state inspection. However, in the printer 1, the 15 nozzles Nz form one block (one nozzle row is divided into 12 blocks), and the ejection state inspection is performed in units of blocks.
The discharge state inspection has been described above.

  In the above configuration, in order to realize a function of inspecting the ink ejection state of each nozzle of the printer 1 and automatically performing maintenance according to the ejection state or performing maintenance according to a user instruction. The firmware executed in the printer 1 and the printer driver executed in the PC 100 are provided with programs for realizing these functions. Note that since the functions realized by the printer driver and the functions realized by the firmware are complementary to each other, the function sharing between the printer driver and the firmware described in the subsequent nozzle check sequence is merely an example. In the present embodiment, the measurement unit described in the claims corresponds to the discharge state detection unit 15, and the determination unit corresponds to the discharge state detection unit 15 and the controller 18. The maintenance means corresponds to the cap unit 16, the head unit 13, and the controller 18. The check image printing unit corresponds to the paper transport unit 11, the carriage unit 12, the head unit 13, the controller 18, the CPU 112, the RAM 113, and the like. The accepting means corresponds to the mouse 150, keyboard 151, CPU 112, RAM 113, etc., and the guiding means corresponds to the display 152, CPU 112, RAM 113, etc.

1-3. Operation Next, a nozzle check sequence performed in the printing system having the above configuration will be described. In the printing system of the present embodiment, when printing is executed in the printer 1 upon receiving a printing instruction from the PC 100, the nozzle check shown in FIG. 9 is performed immediately before the printing operation corresponding to the print job at a rate of once every plural times. A sequence is performed. The nozzle check sequence determines whether the ink ejection state of each nozzle is a clogged state, an unstable ejection state, or a normal state, and if there are two states other than the normal state, a procedure corresponding to each state This is a process for performing maintenance. The nozzle check sequence is not limited to the configuration executed in association with the printing operation, but may be a configuration executed when an instruction to perform maintenance is issued from the PC 100.

1-3-1. Nozzle Check Sequence The nozzle check sequence will be specifically described with reference to FIG. First, the controller 18 of the printer 1 initializes the number of maintenance operations (S100). Specifically, a variable that holds the number of times of performing maintenance including the suction operation and a variable that holds the number of times of performing maintenance that does not include the suction operation are initialized to “0”. Subsequently, the controller 18 executes a discharge state inspection process (S100, determination process, measurement process). The detailed flow of the ejection state inspection process will be described later with reference to FIG. 10, but the operation principle and the processing content are as described above.

  Subsequently, the controller 18 determines whether or not the number of clogged nozzles is equal to or greater than a predetermined number as a result of executing the ejection state inspection process shown in FIG. 10 (S105). Specifically, as a result of inspecting all the nozzles in the six nozzle rows, it is determined whether or not there are more than a predetermined number of clogged nozzles. The predetermined number is a numerical value used as a condition for performing maintenance including suction operation, and is determined in advance in consideration of the balance between the influence of the printing result on image quality and cost (time required for maintenance and ink consumption). Yes. In the present embodiment, when the number of clogged nozzles is less than a predetermined number, maintenance including a suction operation is not performed.

  Subsequently, when it is determined in S110 that the number of clogged nozzles is not a predetermined number or more, the controller 18 determines whether or not the number of nozzles in an unstable discharge state is a predetermined number or more (S115). If the number of clogged nozzles and unstable nozzles is less than the predetermined number, the nozzle check sequence is terminated. For the same reason as described in S110, in this embodiment, when the number of nozzles in the unstable ejection state is less than a predetermined number, the processes after S135 are not performed. It should be noted that the predetermined number in S110 and S115 are not limited to the same value, and are set as appropriate in consideration of the balance between the effect on the image quality as it is and the cost of maintenance.

  When it is determined in S110 that the number of clogged nozzles exceeds the predetermined number, the controller 18 determines whether or not the maintenance including the suction operation has been performed at least M times (M is a natural number). (S120). When it is determined that it has not been performed M times or more, the controller 18 performs maintenance including a suction operation (S125, maintenance process). The maintenance including the suction operation is maintenance including at least the suction operation, and in this embodiment, the suction operation, the flushing operation, and the wiping operation are performed. When there are more than a certain number of clogged nozzles, the effect on the image quality is greater than when there are nozzles with unstable ejection, so it is more effective than other maintenance methods to quickly eliminate clogged conditions. By automatically performing maintenance including a typical suction operation, it is possible to contribute to quickly eliminating the clogged state. After the maintenance is completed, the controller 18 increments a variable that holds the number of times of maintenance including the suction operation, and returns to S105. When it is determined in S120 that the maintenance including the suction operation has been performed M times or more, the controller 18 notifies the PC 100 of information that the clogged nozzle has not recovered, and the PC 100 displays the display. An error message is displayed in 152 (S130). After S130, the nozzle check sequence ends.

  If it is determined in S115 that there are a predetermined number or more of nozzles in the unstable ejection state, the controller 18 determines whether or not the maintenance performed in accordance with the user's instruction has been performed N times or more (S135). If it has not been performed N times or more, a check image is printed (S140, check image printing step). Specifically, the controller 18 notifies the PC 100 of information indicating the nozzles in the unstable ejection state and the nozzle row having the nozzles, and the printer driver generates a check image using the notified information and prints the check image. Print data to be transmitted to the printer 1, and the controller 18 of the printer 1 controls the paper transport unit 11, the carriage unit 12, the head unit 13, and the like to print a check image.

  The check image includes a nozzle check pattern (hereinafter simply referred to as a pattern) for allowing the user to check the occurrence state of the unstable ejection state. The pattern includes a dot group formed on the paper by the nozzle in the normal state together with a dot group formed on the paper by the nozzle in the unstable discharge state so that the occurrence state of the unstable discharge state can be easily recognized. The For example, when some unstable ejection state nozzles are detected in the nozzle row NLk (black nozzle row) among the 6 nozzle rows in S105, ink is ejected from the normal state nozzles belonging to the nozzle row NLk. The PC 100 generates a check image including a pattern composed of the dot group formed by the above and the dot group formed by ejecting ink from the unstable ejection state nozzles belonging to the nozzle row NLk.

  FIG. 11A is a diagram illustrating an example of a pattern included in a check image generated by the PC 100. When the processing of the printer driver is executed by the PC 100, a pattern 50a configured to be printed as a black straight line extending in the sub-scanning direction on the paper using only all nozzles belonging to the nozzle row NLk, and nozzles A check image 50 including a pattern 50b configured to be printed on a sheet as a rectangular patch whose main scanning direction is longer than the sub-scanning direction using only all nozzle rows belonging to the row NLk is generated. Then, print data is generated by performing resolution conversion processing, color conversion processing, halftone processing, rearrangement processing, and the like on the check image 50 including the patterns 50 a and 50 b by processing of the printer driver, and is transmitted to the printer 1. Is done. Based on the received print data, the printer 1 prints a check image 50 including patterns 50a and 50b using only the nozzle array NLk on a sheet.

FIG. 11B shows an example of an enlarged view of the patterns 50a and 50b included in the check image 50 printed on the paper. 50a1 corresponds to the pattern 50a, and 50b1 corresponds to the pattern 50b. In FIG. 11B, dots arranged in the main scanning direction are dots formed by ink droplets ejected from the same nozzle. For example, when the nozzle row NLk includes a nozzle Nz (#X) whose ink ejection direction is bent in the sub-scanning direction, the dot group Ds _X formed by the nozzle Nz (#X) is an adjacent normal state nozzle. Partly overlaps with one dot group Ds _X-1 formed by (Nz (# X-1), Nz (# X + 1)) and is formed apart from the other dot group Ds _{X + 1} . Therefore, as shown in FIG. 11C, the check image 50 is printed so that the straight line is partially interrupted (e1) or the patch has a print medium color streak (e2) extending in the main scanning direction. . For example, when the nozzle row NLk includes a nozzle Nz (#Y) whose ink ejection direction is bent in the main scanning direction, the dot group Ds _Y formed by the nozzle Nz (#Y) is the dot group Ds _Y. The whole is printed with a shift in the main scanning direction from the dot group formed by the nozzles in the normal state. For this reason, as shown in FIG. 11C, the check image 50 is printed with the straight line partially distorted (e3) and part of the side extending in the sub-scanning direction of the patch (e4).

  When there is a nozzle whose ejection direction is bent in the sub-scanning direction, the pattern 50b that causes ink to land in a region that is somewhat longer in the main scanning direction than the straight line extending in the sub-scanning direction such as the pattern 50a. However, it is easy for the user to recognize the printing result by the nozzle in the unstable ejection state. When there is a nozzle whose ejection direction is bent in the main scanning direction, the straight pattern 50a extending in the sub-scanning direction makes it easier for the user to recognize the bending in the main scanning direction than the pattern 50b.

  As described above, in the present embodiment, a pattern configured using only the unstable ejection state nozzles and the normal state nozzles of the nozzle row including the nozzles is printed. That is, the ink color patterns of all the nozzle rows are not always printed using all the nozzle rows, and the patterns of the nozzles of unnecessary nozzle rows for making the unstable ejection state visible are not printed. For this reason, it is possible to reduce the amount of ink consumed for printing the check image, and to make it easier for the user to visually recognize the printing result of the nozzles in the unstable ejection state. It should be noted that the pattern is not limited to forming all the nozzle rows including the nozzles in the unstable ejection state, but for example, only the nozzles in the unstable ejection state and a predetermined number of nozzles adjacent to the front and rear thereof are used. A pattern may be printed (see FIG. 12A). As a result, the ink consumption can be further reduced, and a dot group of unstable ejection nozzles is printed at the center of the pattern in the sub-scanning direction. Can do. In addition to the above example, at least a dot group formed by nozzles in an unstable discharge state and a dot group formed by nozzles in a normal state for comparison with the printing result of nozzles in an unstable discharge state If the check image is printed so as to include, the number of nozzles in the unstable discharge state, the position of the nozzle in the nozzle row including the nozzle in the unstable discharge state, and the nozzle row including the nozzle in the unstable discharge state Depending on the number and the like, check images having various configurations may be printed in S140.

  After the check image is printed in S140, the PC 100 causes the printer driver to display a message prompting the user to select whether or not to perform maintenance on the display 152, and the user performs a selection operation using the mouse 150 or the keyboard 151. The printer driver acquires information indicating the operation (S145, reception process). Subsequently, based on the information acquired in S145, whether or not the user has instructed to perform maintenance is determined by the process of the printer driver (S150), and it is determined that the user has not instructed to perform maintenance. In the case where it is detected, the nozzle check sequence is ended, and then the print job is executed.

If it is determined in S150 that the user has instructed the maintenance, the controller 18 determines whether or not the maintenance that does not include the suction operation has been performed N ₁ (N ₁ is a natural number less than N) times or more. (S155). If maintenance without the sucking action not been performed _one or more times N, maintenance is performed without the suction operation (S160, the maintenance process). Specifically, for example, the controller 18 performs a flushing operation and a wiping operation as maintenance not including the suction operation. After the maintenance is completed, the controller 18 increments the value of the variable that holds the number of times of maintenance not including the suction operation, and returns to S105.

If maintenance without the suction operation is determined at _least once N is Performed at S155, the controller 18 determines whether or not maintenance (N-N ₁₎ times or more Performed or including the suction operation ( S165). If the maintenance including the suction operation has not been performed (N−N ₁ ) times or more, the controller 18 performs the maintenance including the suction operation (S170, maintenance process). After the maintenance is completed, the controller 18 increments the value of the variable that holds the number of times of maintenance including the suction operation, and returns to S105. In other words, in this embodiment, when the user is instructed to perform maintenance, first, maintenance is performed that does not include the suction operation, and recovery is attempted with as little ink consumption as possible, and maintenance that does not include the N _one suction operation is performed. If the ink does not recover, it is possible to increase the possibility of recovery of the unstable ejection state by performing maintenance including a suction operation that consumes a large amount of ink but has a high possibility of recovery. If it has not been performed (N−N ₁ ) times or more in S165, the nozzle check sequence is terminated.

  If it is determined in S135 that the maintenance by the user instruction has been performed N times or more, an error message indicating that the maintenance is attempted but the unstable discharge state is not recovered is displayed on the display 152 (S175, guidance process). The nozzle check sequence ends. Therefore, if the unstable ejection state does not recover even after the maintenance is repeated a predetermined number of times, the printing of the check image and the visual check can be repeated to inform the user of the failure. Detailed information on parts replacement and repair may be given.

  As described above, in the present embodiment, if it is determined that there is a nozzle in an unstable discharge state, whether a check image including a nozzle check pattern is printed and the user visually checks the pattern to perform maintenance. In order to let the user decide and follow that decision, time and ink consumption can be reduced compared to the configuration where maintenance is always performed automatically without exception when there is a nozzle in an unstable discharge state, Can meet user's request.

1-3-2. Discharge State Inspection Process A specific procedure of the discharge state inspection process in S105 of FIG. 9 will be described with reference to FIG. In the ejection state inspection process, the detection control unit 47 first determines a nozzle row to be inspected (S200). As described in FIG. 3, the head HD is provided with six nozzle rows. Of these six nozzle rows, one nozzle row is determined as the nozzle row to be inspected. When the nozzle row to be inspected is determined, the detection control unit 47 determines a block to be inspected (S205). As described above, one block includes 15 nozzles Nz, and one nozzle row includes 12 blocks. In S205, one block to be inspected among the 12 blocks is determined.

  When the block to be inspected is determined, the detection control unit 47 performs ejection of ink droplets and detection of the voltage signal SG for the block (S210). Specifically, an ink droplet is ejected from each nozzle Nz belonging to the target block, and an electrical change caused by ejection of the ink droplet, specifically a potential difference associated with each nozzle Nz. Obtain ΔV. When the processing of S210 is completed for all the nozzles belonging to one block, the detection control unit 47 determines whether or not ink droplet ejection and signal detection have been executed a predetermined number of times per nozzle (S215). If it is less than the predetermined number, S210 is repeatedly executed until the predetermined number is reached. The detection results of ΔV for a plurality of times are overwritten for a plurality of times without being overwritten and erased.

  After being executed a predetermined number of times, the detection control unit 47 derives a representative value (median value, mode value, average value, etc.) of the potential difference ΔV for a plurality of times for each nozzle, and uses the representative value as two threshold values (first threshold value). The ink discharge state is determined for each nozzle by comparing with TH1 and the second threshold value TH2 (S220). The comparison result is stored in the storage unit of the detection control unit 47. For example, a value indicating “first threshold value TH1 or more” or “less than first threshold value TH1 and more than second threshold value TH2” or “less than second threshold value TH2” is stored as a comparison result. In addition, by using a representative value of a plurality of inspection results for one nozzle for comparison, it is possible to prevent erroneous determination of the ink ejection state.

  Subsequently, the detection control unit 47 determines whether the block to be inspected is the last block in the nozzle row to be inspected (S225). If it is not the final block, the process returns to S205, and the above-described processing is performed on the next block. If it is the last block, the detection control unit 47 determines whether or not the inspection target nozzle row is the last nozzle row of the plurality of nozzle rows (S230). If it is not the last nozzle row, the controller 18 returns to S200 and performs the above-described processing for the next nozzle row. If it is the last nozzle row, the ejection state inspection process is terminated while retaining the determination results so far, and the process returns to the calling process.

2. Other Embodiments The technical scope of the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the scope of the present invention. For example, the measurement unit may be configured to detect the ink ejection state by irradiating the laser beam and determining whether or not the light is blocked by the ink droplet ejected from the nozzle. Also, in the case where a configuration capable of detecting the ink droplet ejection direction is provided (for example, the laser surface La is irradiated in parallel with the nozzle surface at a distance A from the nozzle surface, and the nozzle surface at a position B away from the nozzle surface). A check image including a pattern in which the print result is easy to visually recognize according to the direction of the bend. You may do it. For example, when there are nozzles whose discharge direction is bent in the main scanning direction in the black nozzle row NLk and nozzles whose discharge direction is bent in the sub-scanning direction are present in the cyan nozzle row NLc, a straight line extending in the sub-scanning direction using the nozzle row NLk. (50a1 in FIG. 12B), and a rectangular pattern in which the main scanning direction is longer than the sub-scanning direction is printed using the nozzles in the unstable ejection state of the nozzle row NLc and the normal nozzles in the vicinity thereof (FIG. 12B). 12B 50c1).

  In the above embodiment, the printing system including the PC 100 and the printer 1 has been described. It may be applied to a multifunction printer.

  DESCRIPTION OF SYMBOLS 1: Printer, 9: Internal I / F, 10: External I / F, 11: Paper conveyance part, 12: Carriage part, 13: Head part, 15: Ejection state detection part, 16: Cap part, 18: Controller, 31: Cap, 33: Wiper, 47: Detection control unit, 50: Check image, 50a: Pattern, 50b: Pattern, 100: PC, 110: HDD, 111: RAM, 112: CPU, 113: ROM, 114: External I / F, 115: internal I / F, 150: mouse, 151: keyboard, 152: display, 222: nozzle plate, 313: detection electrode, CR: carriage, HD: head, Ds: dot group, Nz: nozzle .

Claims (8)

Measuring means for measuring an actual value indicating the ejection state of the ink ejected from the nozzle;
A determination unit that determines which of the three states of a normal state, an unstable discharge state, and a clogged state is the ink discharge state by using the measured value;
When it is determined that there is a nozzle in the unstable discharge state, a check image printing unit that prints a check image including a nozzle check pattern used for a visual check of the occurrence state of the unstable discharge state;
Accepting means for accepting an instruction from the user indicating whether or not maintenance is necessary to eliminate the unstable discharge state after printing the check image;
Maintenance means for performing the maintenance when the user's instruction indicates that the maintenance needs to be performed;
A printing system comprising: The maintenance unit automatically performs maintenance including a suction operation regardless of the user's instruction when the determination unit determines that the clogged nozzle exists.
The printing system according to claim 1. The measurement of the actual measurement value by the measurement unit is performed when a nozzle check sequence is started, and thereafter repeatedly performed every time maintenance is performed by the maintenance unit.
When it is determined that there is a nozzle in the unstable discharge state, the maintenance has been performed N times (N is a natural number) that has been determined in advance by the user's instruction since the start of the nozzle check sequence. In the case of, further comprising a guide means for guiding the error message to the user,
The check image printing means does not print the check image when the maintenance according to the user instruction has been performed N times or more.
The printing system according to claim 1 or 2. When the user's instruction that the maintenance needs to be performed is received after the nozzle check pattern is printed, the maintenance means first performs maintenance that does not include the suction operation, and maintenance that does not include the suction operation. If the nozzle in the unstable discharge state does not recover to the normal state even after N ₁ times (N ₁ is a natural number less than N) performed in advance, maintenance including the suction operation is performed.
The printing system according to claim 3. The nozzle check pattern included in the check image is:
A dot group formed by ink droplets ejected from the nozzle in the unstable ejection state and a dot group for comparison with the dot group, the dots formed by ink droplets ejected from the nozzle in the normal state And a group including at least a group,
At least one of the number of nozzles in the unstable discharge state, the position of the nozzles in the nozzle row including the nozzles in the unstable discharge state, and the number of nozzle rows including the nozzles in the unstable discharge state Configured according to one,
The printing system according to claim 1. The measuring means calculates a potential change amount associated with a capacitance change between a flat plate electrode facing the ink array direction with respect to the nozzle array surface and a flat electrode provided on the nozzle array surface. , Measured as the actual value indicating the ink discharge state,
The printing system according to claim 1. A measurement process for measuring an actual value indicating an ejection state of ink ejected from the nozzle;
A determination step of determining which of the three states of a normal state, an unstable discharge state, and a clogged state is the ink discharge state by using the measured value;
When it is determined that there is a nozzle in the unstable discharge state, a check image printing step for printing a check image including a nozzle check pattern used for a visual check of the occurrence state of the unstable discharge state;
An accepting step of accepting an instruction of the user indicating whether or not maintenance is necessary to eliminate the unstable discharge state after printing the check image;
When the user instruction indicates that the maintenance needs to be performed, a maintenance process for performing the maintenance;
A maintenance method for a printing apparatus including: A measurement function for measuring an actual value indicating an ejection state of ink ejected from the nozzle;
A determination function that determines which of the three states of a normal state, an unstable discharge state, and a clogged state is the ink discharge state by using the measured value;
A check image printing function for printing a check image including a nozzle check pattern used for a visual check of the occurrence state of the unstable discharge state when it is determined that the nozzle in the unstable discharge state exists;
A reception function for receiving an instruction from the user indicating whether or not maintenance is necessary to eliminate the unstable discharge state after printing the check image;
A maintenance function for performing the maintenance when the user's instruction indicates that the maintenance needs to be performed;
Maintenance control program for a printing device that enables a computer to realize

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