JP2010214812A - Fluid ejecting apparatus and control method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inspect nozzles without a time necessary for image formation being increased. <P>SOLUTION: Image formation for one pass is carried out when the nozzle 23 including a plurality of nozzles ejects an ink to a recording paper S in an image forming region while a printing head 24 moves a forward way or a return way of a movable region once. When an image is formed to the recording paper S by carrying out the image formation of one pass by a plurality of the number of times, the nozzles within an inspection object nozzle maximum number which can be inspected while the printing head 24 moves in a region opposed to either of inspection regions 52 and 152 among the nozzles which eject the ink in image formation of the next pass are sequentially set to be inspection object nozzles. The set inspection object nozzles are inspected while the nozzle 23 moves in the region opposed to the inspection regions 52 and 152 between passes. The nozzles which effect degradation of an image quality can be inspected without movement of the head being stopped once for the nozzle inspection. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fluid ejection device and a control method thereof.

  2. Description of the Related Art Conventionally, there has been proposed an ink jet printer that performs nozzle inspection to check whether ink droplets are normally ejected from the nozzles of a print head. For example, Patent Document 1 discloses an induced current generated by discharging an ink droplet charged from a nozzle of a head to an ink droplet receiving portion in an ink jet printer having a head having four nozzle rows of 180 nozzles. It is described that nozzle inspection is performed by detecting. Further, it has been proposed that the nozzle inspection be performed at an appropriate timing during the printing process, or at a timing before printing such as when the power is turned on, when paper is fed, or when print data is acquired.

JP 2006-110853 A

  By the way, in order to properly detect nozzle ejection defects, it is desirable to perform nozzle inspection immediately before printing or during printing processing. However, if the user performs a nozzle inspection after instructing printing, there is a problem that the time required for completing the printing process becomes longer. For example, if nozzle inspection is performed for all nozzles immediately before printing, the start of printing is delayed by the nozzle inspection time. Even when the nozzle inspection is performed during the printing process, if the printing is temporarily stopped and the nozzle inspection is performed for all the nozzles, it takes a long time to complete the printing.

  The present invention has been made in view of the above-described problems, and has as its main object to perform nozzle inspection without increasing the time required for image formation.

  The present invention adopts the following means in order to achieve the main object described above.

The fluid ejection device of the present invention is
A head having a plurality of nozzles and discharging fluid from the nozzles toward the target while moving in the main scanning direction;
The head is reciprocated within a movable region provided in the main scanning direction including an image forming region in which the head discharges fluid to the target and a non-image forming region in which the head does not discharge fluid to the target. A head reciprocating means;
Inspection means for performing nozzle inspection for inspecting whether fluid is normally discharged from the nozzle;
By controlling the head and the head reciprocating means so that the head moves once in the forward or backward path of the movable area, the fluid is discharged from the nozzle to the target in the image forming area for one pass. When forming an image on the target by performing image formation for one pass a plurality of times and forming the image on the target, the head is located in the non-image formation region between the passes among the plurality of nozzles. Nozzles within the inspectable number, which is the number of nozzles that can be inspected by the nozzle, are sequentially set as inspection target nozzles to be subjected to the nozzle inspection, and between the passes, Control means for controlling the inspection means to perform the nozzle inspection of the inspection target nozzle while the head moves in the non-image forming region;
It is equipped with.

  In the fluid ejection device of the present invention, a head having a plurality of nozzles that eject fluid to the target is provided in the main scanning direction including an image forming region that ejects fluid to the target and a non-image forming region that does not eject fluid to the target. The head is reciprocated by the head reciprocating means within the range of the movable region. Then, the head and the head reciprocating means are controlled to perform image formation for one pass by discharging fluid from the nozzle to the target in the image forming area while the head moves once in the forward path or the backward path of the movable area. When forming an image on the target by performing image formation for one pass multiple times, the inspection means can inspect the nozzle while the head moves in the non-image forming area between the passes among the plurality of nozzles. Sequentially set the nozzles within the inspectable number, which is the number of nozzles, to the inspection target nozzles that are the target of the nozzle inspection for inspecting whether or not the fluid is normally discharged from the nozzles. The inspection unit is controlled to perform the nozzle inspection of the inspection target nozzle while the head moves in the non-image forming area. As a result, nozzle inspection is performed only for the inspection target nozzles set within the inspectable number while the head moves in the non-image forming area between passes during image formation. The movement of the head is not stopped once. Therefore, nozzle inspection can be performed without increasing the time required for image formation.

  The fluid ejection device of the present invention further comprises storage means capable of storing image data representing an image for the next one pass formed on the target, and the control means is based on the image data read from the storage means Then, in the next one-pass image formation, a nozzle that discharges fluid to the target may be specified, and the nozzle may be preferentially set as the inspection target nozzle. In this way, it is possible to preferentially inspect nozzles that affect image quality degradation.

  In this case, the head is a head having a nozzle row in which a plurality of nozzles are formed in a direction substantially orthogonal to the main scanning direction, and the control means performs one time for forming an image on the target. In setting the nozzle to be inspected by controlling the head and the head reciprocating means so as to perform image formation in a band system in which the area where fluid can be discharged onto the target in the pass does not overlap between passes, The nozzle that discharges fluid to the target in image formation for one pass, and a plurality of continuous nozzles in the nozzle row may be set as a preferential setting to the inspection target nozzle. In the case of performing image formation by the band method, when two or more continuous nozzles become defective in ejection, image quality deterioration becomes remarkable. In this type of fluid ejection device, the presence or absence of such ejection failure can be detected efficiently.

  In the fluid ejection device of the present invention having the storage means described above, the storage means is a means capable of storing image data representing images for at least two subsequent passes formed on the target, and the control means , It is possible to specify a nozzle for ejecting fluid in the image formation of the next and subsequent passes among the image formation on the target this time based on the image data read from the storage means, and the priority over the inspectable number When the number of nozzles set as inspection target nozzles is small, in addition to the nozzle set preferentially as the inspection target nozzle, the nozzles that discharge fluid in the image formation of the next and subsequent passes are preferentially checked. It is good also as a means to set to an object nozzle. In this way, when the number of nozzles that discharge fluid to the target in the next one-pass image formation is less than the number that can be inspected, the nozzles that affect the image quality degradation in the subsequent and subsequent pass image formation are inspected in advance. I can keep it.

  In the fluid ejection device of the present invention having the above-described storage unit, the control unit may be configured such that the number of nozzles ejecting fluid to the target in the image formation for the next specified one pass is greater than the inspectable number. When there are many nozzles, among the specified nozzles, a nozzle that has never been set as the inspection target nozzle during image formation on the same target may be set as the inspection target nozzle with the highest priority. In this way, it is possible to inspect more different nozzles among nozzles that affect image quality degradation.

  In the fluid ejection device of the present invention, the head has a nozzle row in which a plurality of the nozzles are formed in a direction substantially orthogonal to the main scanning direction, and the control unit is configured to form an image on the target. The head and the head reciprocating means are controlled to set the nozzle to be inspected so as to perform image formation in a band system in which a region where fluid can be discharged onto the target in one pass does not overlap between passes. In this case, a plurality of continuous nozzles in the nozzle row may be preferentially set as the inspection target nozzle. In the case of performing image formation by the band method, when two or more continuous nozzles become defective in ejection, image quality deterioration becomes remarkable. In this type of fluid ejection device, the presence or absence of such ejection failure can be detected efficiently. In this case, the control unit may be a unit that does not set the same nozzle as the inspection target nozzle again while there is a nozzle that has not been subjected to the nozzle inspection even during image formation on the same target. In this way, more different nozzles can be inspected during image formation.

The control method of the fluid ejection device of the present invention includes:
A head having a plurality of nozzles that discharges fluid from the nozzles toward the target while moving in the main scanning direction, an image forming region in which the head discharges fluid to the target, and the head discharges fluid to the target A head reciprocating means for reciprocating the head within a range of a movable region provided in the main scanning direction including a non-image forming region that does not perform, and a nozzle for inspecting whether fluid is normally ejected from the nozzle A control method of a fluid ejection device provided with inspection means for performing inspection,
By controlling the head and the head reciprocating means so that the head moves once in the forward or backward path of the movable area, the fluid is discharged from the nozzle to the target in the image forming area for one pass. In forming the image on the target by performing image formation for one pass a plurality of times and forming the image on the target, the head is located in the non-image formation region between the passes among the plurality of nozzles. The nozzles within the inspectable number, which is the number of nozzles that can be inspected by the inspection means, are sequentially set as the inspection target nozzles to be subjected to the nozzle inspection, and Controlling the inspection means to perform the nozzle inspection of the inspection target nozzle while the head moves in the non-image forming region;
Is included.

  In the control method of the fluid ejection device of the present invention, the head having a plurality of nozzles that eject fluid to the target includes an image forming area that ejects fluid to the target and a non-image forming area that does not eject fluid to the target. The fluid discharge is provided with an inspection means for inspecting whether or not the fluid is normally discharged from the nozzle, and is reciprocated by the head reciprocating means within the range of the movable region provided in the direction. In the apparatus, the head and the head reciprocating means are controlled to form a one-pass image by discharging fluid from the nozzle to the target in the image forming area while the head moves once in the forward or backward path of the movable area. When forming an image on a target by performing image formation for one pass a plurality of times, the head does not move between the passes among the plurality of nozzles. Nozzles within the inspectable number, which is the number of nozzles that can be inspected by the inspection means while moving in the image forming area, are sequentially set as inspection target nozzles to be inspected for nozzle inspection. The inspection unit is controlled to perform the nozzle inspection of the inspection target nozzle while the head moves in the non-image forming area. As a result, nozzle inspection is performed only for the inspection target nozzles set within the inspectable number while the head moves in the non-image forming area between passes during image formation. The movement of the head is not stopped once. Therefore, nozzle inspection can be performed without increasing the time required for image formation. Note that the method for controlling a fluid ejection device of the present invention may include a step for realizing the function of any of the fluid ejection devices described above.

FIG. 2 is a configuration diagram showing an outline of the configuration of a printer 20 according to the present embodiment. FIG. 3 is a block diagram showing electrical connection of a print head 24. FIG. 2 is a block diagram showing an outline of the configuration of a nozzle inspection device 50. FIG. 4 is an explanatory diagram of movement of a carriage 22 and formation of an image on a recording sheet S by the movement. 6 is a flowchart illustrating an example of a print processing routine. The flowchart which shows an example of a test object nozzle setting routine. Explanatory drawing of the nozzle used when forming the image for 1 pass. Explanatory drawing which shows an example of the test object nozzle memorize | stored in the test object nozzle storage area. The block diagram in case the printer 20 is further provided with test | inspection area | regions 52a and 152a. Explanatory drawing of PG and SG adjustment by PG adjustment mechanism 80 and SG adjustment mechanism 90. FIG. Explanatory drawing which shows the print head 24 in the case of having a some nozzle row. Explanatory drawing of the nozzle test | inspection using light. Explanatory drawing which shows the example of arrangement | positioning of another electrode member.

  Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram illustrating an example of a schematic configuration of the printer 20 according to the present embodiment, FIG. 2 is a block diagram illustrating electrical connection of the print head 24, and FIG. 3 is a nozzle inspection device 50. It is a block diagram which shows the outline of a structure.

  As shown in FIG. 1, the printer 20 of the present embodiment includes a printing mechanism 21 having a printing head 24 that ejects ink as a fluid onto a recording sheet S as a target, and a head driving substrate mounted on a carriage 22. 62, a paper feed mechanism 30 that conveys the recording paper S, a capping device 31 that performs sealing and cleaning of the print head 24, and a nozzle test to determine whether ink is being ejected from the nozzles 23 of the print head 24. Nozzle inspection apparatuses 50 and 150 to be executed and a controller 70 for controlling the entire printer 20 are provided.

  The printing mechanism 21 includes a carriage 22 that reciprocates left and right (main scanning direction) along a carriage shaft 28 by a carriage belt 32, and a print head 24 that applies pressure to each color ink and ejects ink droplets as fluid from nozzles 23. And an ink cartridge 26 that stores ink of each color and supplies the stored ink to the print head 24. As the carriage 22 is driven by the carriage motor 34a, the carriage belt 32 installed between the carriage motor 34a attached to the right side of the casing 39 and the driven roller 34b attached to the left side of the casing 39 is driven. Move. A linear encoder 25 that detects the position of the carriage 22 is disposed on the rear surface of the carriage 22, and the position of the carriage 22 can be managed using the linear encoder 25. The carriage 22 has a head driving substrate 62 for driving the print head 24. The print head 24 is provided at the lower part of the carriage 22 and ejects ink from nozzles 23 provided on the lower surface of the print head 24 by pressurizing the ink. The print head 24 is connected to the ground. As shown in FIG. 2, a nozzle row 68 in which a plurality of nozzles 23 that eject black (K) ink is arranged is provided on the lower surface of the print head 24. In the print head 24, 180 nozzles 23 are arranged along the conveyance direction of the recording paper S substantially orthogonal to the main scanning direction to form a nozzle row 68. Each nozzle 23 is provided with a piezoelectric element 66 as a driving element for ejecting ink droplets. By applying a voltage to the piezoelectric element 66, the piezoelectric element 66 is deformed to pressurize the ink and press the nozzle 23. Discharge. The ink cartridge 26 is mounted on the carriage 22 and contains black (K) ink containing pigment or dye as a colorant in water as a solvent.

  As shown in FIG. 2, the head driving substrate 62 has a mask circuit 64 for applying a voltage to the piezoelectric element 66. The head driving substrate 62 is connected to a flat cable 63 (see FIG. 1) via a connector portion (not shown), and exchanges signals with the controller 70 via the flat cable 63. The mask circuit 64 is provided corresponding to the piezoelectric element 66 that drives each nozzle 23. The mask circuit 64 receives the original signal ODRV and the print signal PRTn generated by the head drive waveform generation circuit 60 on the control board (not shown). The original signal ODRV is composed of a first pulse P1, a second pulse P2, and a third pulse P3 that are included in an interval of one pixel (within a time during which the carriage 22 crosses the interval of one pixel). The original signal ODRV having these three pulses P1 to P3 as a repeating unit is referred to as one pixel section in this embodiment. The print signal PRTn is a signal generated based on the presence or absence of dots formed on the recording paper S and the size thereof. Note that n at the end of the print signal PRTn is a number for specifying the nozzles included in the nozzle row. In this embodiment, since the nozzle row is composed of 180 nozzles, n is any number from 1 to 180. It becomes a numerical value. When the original signal ODRV and the print signal PRTn are input, the mask circuit 64 outputs necessary pulses among the first pulse P1, the second pulse P2, and the third pulse P3 based on these signals as the drive signal DRVn (n Is output to the piezoelectric element 66 of the nozzle 23 as the print signal PRTn. Specifically, when only the first pulse P1 is output from the mask circuit 64 to the piezoelectric element 66, one shot of ink droplet is ejected from the nozzle 23, and a small size dot (small dot) is formed on the recording paper S. It is formed. When the first pulse P1 and the second pulse P2 are output to the piezoelectric element 66, two shots of ink droplets are ejected from the nozzle 23, and medium-sized dots (medium dots) are formed on the recording paper S. The Further, when the first pulse P1, the second pulse P2, and the third pulse P3 are output to the piezoelectric element 66, three shots of ink droplets are ejected from the nozzle 23, and a large size dot (large size) is printed on the recording paper S. Dot) is formed. As described above, the printer 20 can form three types of dots by adjusting the amount of ink ejected in one pixel section.

  As shown in FIG. 1, the paper feed mechanism 30 is placed on a paper feed roller 35 that is driven by a drive motor 33 and transports the recording paper S from the back to the front in the drawing or a tray (not shown). A paper feed roller (not shown) that feeds the recording paper S to the platen 29, a paper discharge roller (not shown) that transports the recording paper S ejected by the platen 29 to a paper discharge tray (not shown), and the like are provided.

  The capping device 31 is disposed at an initial position (home position) of the carriage 22, and a sealing member made of an insulator such as silicon rubber is provided at an opening edge thereof. Although not shown, the capping device 31 is provided with a suction pump and an air release valve. The suction pump can forcibly suck out ink from the nozzles 23 by generating a negative pressure while the capping device 31 is raised and is in close contact with the print head 24 during cleaning. The air release valve is used to return the inside of the housing to atmospheric pressure after the cleaning is completed. The capping device 31 is also used when sealing the nozzles 23 to prevent the nozzles 23 from drying during printing pauses or the like.

  The nozzle inspection device 50 is disposed on the right side (home position side) of the print head 24 in the main scanning direction, and receives ink droplets ejected from the nozzles 23 of the print head 24 as shown in FIG. A possible flushing box 40, a voltage application circuit 53 for generating a predetermined potential difference between the print head 24 and the electrode member 42 by setting the electrode member 42 in the flushing box 40 to a predetermined potential, and the voltage of the electrode member 42 And a voltage detection circuit 54 for detecting a change.

  The flushing box 40 serves as both a region for ejecting ink for the purpose of preventing clogging of the nozzles 23 and a region for receiving ink when performing nozzle inspection. The flushing box 40 includes an ink absorbing member 41 and an electrode member 42 disposed on the upper surface of the ink absorbing member 41. The ink absorbing member 41 is formed of a highly permeable sponge, nonwoven fabric, or the like that allows the landed ink droplets to move downward quickly. The electrode member 42 is a mesh-like thin plate made of stainless steel (SUS). The electrode member 42 serves to prevent the ink absorbing member 41 from absorbing ink and bulging upward, and at the time of nozzle inspection, the print head 24. It also plays a role as a counter electrode opposite to. Since the electrode member 42 is formed in a mesh shape, the ink ejected from the print head 24 is allowed to move to the ink absorbing member 41. When the electrode member 42 is arranged on the upper surface of the ink absorbing member 41, the heads of the three support rods 43a integrally formed on the bottom surface of the cap 43 are inserted into the round holes provided at the cross points of the mesh. It is caulked by heating and pressurizing its head. In addition, the electrode member 42 is electrically connected to an electrode pin 45 that penetrates the bottom surface of the cap 43 in an airtight and liquidtight state. The area above the ink absorbing member 41 and the electrode member 42 is referred to as an inspection area 52.

  As shown in FIG. 3, the voltage application circuit 53 is connected to the electrode member 42 in the flushing box 40 via the electrode pin 45, and the voltage of the electrical wiring of several volts drawn around inside the printer 20. A circuit that boosts the voltage to several tens to several hundreds volts through a booster circuit (not shown), and applies the DC voltage Ve (for example, 400 V) after the boosting to the electrode member 42 through the resistance element R1 (for example, 1 MΩ) and the switch SW is there.

  The voltage detection circuit 54 is connected to the electrode member 42 in the flushing box 40 and detects a voltage change at the electrode member 42 caused by the ejection of ink from the nozzle 23. The voltage detection circuit 54 integrates the voltage signal at the electrode member 42. The integration circuit 54a that outputs the signal, the inverting amplification circuit 54b that receives and outputs the signal output from the integration circuit 54a, and the signal that is output from the inverting amplification circuit 54b. An A / D conversion circuit 54c that performs D conversion and outputs the result to the controller 70. The integration circuit 54a outputs a large voltage change by integrating the voltage change due to the flight of a plurality of ink droplets ejected from the same nozzle 23 because the voltage change due to the flight of one ink droplet is weak. is there. The inverting amplifier circuit 54b inverts the sign of the voltage change and amplifies and outputs the signal output from the integrating circuit 54a at a predetermined amplification factor determined by the circuit configuration. The A / D conversion circuit 54 c converts the analog signal output from the inverting amplification circuit 54 b into a digital signal and outputs it to the controller 70. The voltage application circuit 53 and the voltage detection circuit 54 are mounted on a substrate in a circuit case 51 that is separate from the cap 43.

  The nozzle inspection device 150 is arranged at the left side of the print head 24 in the main scanning direction (opposite the home position across the recording paper S) as shown in FIG. It is the same composition as. For this reason, the code | symbol of each component of the nozzle test | inspection apparatus 150 shall be the value which added 100 to the code | symbol of each component of the nozzle test | inspection apparatus 50, and the description is abbreviate | omitted.

  The controller 70 is mounted on a control board (not shown) attached to the housing 39 and is configured as a microprocessor centered on the CPU 72 as shown in FIG. 1, and can store various processing programs and rewrite data. A flash ROM 73, a RAM 74 for temporarily storing data, and an interface (I / F) 79 for exchanging data with an external device such as a user personal computer (PC) 110 are provided. The RAM 74 is provided with a print buffer area, and a print job (including image data and information on the type of print medium) sent from the external device such as the user PC 110 via the I / F 79 is provided in this area. Remembered. The controller 70 receives detection signals and the like output from the voltage detection circuits 54 and 154 of the nozzle inspection devices 50 and 150 via an input port (not shown) and is output from an external device (such as the user PC 110). A print job or the like is input via the I / F 79. Further, from the controller 70, a print signal PRTn to the mask circuit 64 mounted on the print head 24, a control signal to the nozzle inspection devices 50 and 150, a drive signal to the drive motor 33, a drive signal to the carriage motor 34a, etc. Is output via an output port (not shown).

  Here, the movement of the carriage 22 and the formation of an image on the recording sheet S will be described with reference to FIG. The carriage 22 can reciprocate in the main scanning direction (left-right direction in the figure) within the range of the movable region shown in FIG. 4 by driving the carriage motor 34a. The movable area in FIG. 4 is represented as the movable area of the nozzle 23, and the carriage 22 in the figure is in a state when the nozzle 23 is at a position a which is the right end in the movable area. The position a is a position where the capping device 31 and the print head 24 face each other, and is the above-described home position. The movable area includes a constant speed section (image forming area) in which the carriage 22 moves at a constant speed V1, acceleration for moving at the speed V1 in the constant speed section, and after moving at the speed V1 in the constant speed section. And an acceleration / deceleration section (non-image forming area) that is a section necessary for deceleration. The carriage 22 forms an image for one pass by ejecting ink from the nozzles 23 to the recording paper S in the image forming area while moving once in the forward or backward path of the movable area. Then, the carriage 22 moves forward or backward in the main scanning direction to form an image for one pass, and the paper feed roller 35 moves in the transport direction (sub scanning direction) orthogonal to the main scanning direction. An image based on the image data stored in the print buffer area of the RAM 74 is formed on the recording paper S by alternately performing the process of sending S.

  For example, when the triangular image A is formed on the recording paper S, first, an area in which the first-pass image of the recording paper S is formed by rotating a paper feeding roller or a paper feeding roller 35 (not shown) is the print head 22. The recording paper S is transported to a position where it can face. Subsequently, the carriage 22 moves from the position a, which is the home position, to the left in FIG. 4 while moving to the speed V1, and moves between the positions a, c in the non-image forming area, and the position c, which is the image forming area, at the speed V1. , D, ink is ejected onto the recording paper S to form the image A1, which is the image of the first pass, and is decelerated from the speed V1 in the non-image forming area after the position d, and the speed 0 at the position e. become. Similarly to the above, the recording paper S is transported to a position where the area where the second pass image is formed can face the print head 22, and the carriage 22 is positioned in the non-image forming area from the position e, opposite to the forward path. Accelerates between e and d to speed V1, ejects ink onto the recording paper S while moving between positions d and c, and forms an image A2 of the second pass, and in a non-image forming area after position c. Decelerate to zero speed at position b. Thereafter, the images A3 and A4 in the third pass and the fourth pass are similarly formed, and the image A is formed on the recording paper S. The carriage 22 decelerates between positions c and a and stops at the position a which is the home position when image formation of the fourth pass, which is the last pass, is completed. The distance between the positions b and c and the distance between the positions d and e are the minimum distances necessary for acceleration up to the speed V1 and deceleration from the speed V1, and the carriage 22 moves between the positions a and c. All that needs to be done is during acceleration when forming the first pass image and during deceleration when forming the last pass image. In the present embodiment, the printer 20 includes an area in which ink can be ejected on the recording paper S in one pass, that is, an area in which the nozzle array 68 passes on the recording paper S in one pass. Then, image formation is performed by a band method for conveying the recording paper S so as not to overlap. Accordingly, the paper feed roller 35 transports the recording paper S between each pass by at least a distance equal to or longer than the length of the nozzle row 68 in the transport direction. As shown in the enlarged portion of the boundary between the second pass and the third pass in FIG. 4, the areas through which the nozzle array 68 passes do not overlap between the passes, but the dots by the ink ejected from the nozzles 23 It may overlap between.

  Further, in the present embodiment, when the carriage 22 moves in the forward path or the backward path of the movable area to form an image on the recording paper S, the nozzle inspection is performed while the nozzle array 68 passes through the area facing the inspection areas 52 and 152. Nozzle inspection can be performed by the devices 50 and 150. For example, before the first pass image formation in FIG. 4, nozzle inspection is performed by ejecting ink from the nozzle 23 while the carriage 22 passes once through the region facing the inspection region 52 between the positions a and c. be able to. Further, since the carriage 22 reciprocates between positions d and e before the second pass image formation, it passes through the region facing the inspection region 152 twice, so that the nozzle inspection can be performed at this time. Before the image formation after the second pass, the inspection region 52 or the inspection region 152 is always passed twice, so that the nozzle inspection can be performed for a large number of nozzles 23 as compared with the nozzle inspection before the first pass image formation. it can. In the present embodiment, a maximum of N1 (for example, 15) nozzle inspection is possible in the nozzle inspection before the image formation in the first pass, and a maximum of N2 (for example, 30) in the nozzle inspection before the image formation after the second pass. ) Nozzle inspection is possible. The values N1 and N2 are determined based on the width of the inspection areas 52 and 152 in the main scanning direction and the moving speed when the carriage 22 passes through the area facing the inspection areas 52 and 152, for example. Is derived by dividing the time that can be inspected, that is, the inspectable time, and dividing the inspectable time by the time required to perform the nozzle inspection of one nozzle.

  Next, the operation of the printer 20 according to the present embodiment configured as described above, in particular, the process of performing the nozzle inspection of the nozzle 23 while performing the process of printing an image on the recording paper S will be described. FIG. 5 is a flowchart illustrating an example of a print processing routine executed by the CPU 72 of the controller 70. This routine is executed when the user operates the user PC 110 to instruct the printer 20 to print an image on the recording paper S, and the CPU 72 receives the print instruction via the I / F 79.

  When this print processing routine is executed, the CPU 72 first receives image data instructed by the user from the user PC 110 via the I / F 79 and starts storing the image data in the print buffer area of the RAM 74 (step S100). ), The execution of the inspection target nozzle setting routine for setting the inspection target nozzle to be the target of the nozzle inspection performed during the printing of the image data is started (step S110), and the carriage motor 34a and the drive motor 33 are controlled to perform the band described above. Movement of the carriage 22 and conveyance of the recording paper S are started so as to perform printing in the system (step S120). The storage of the image data, the execution of the inspection target nozzle setting routine, the movement of the carriage 22 and the conveyance of the recording paper S, which are started in steps S100 to S120, can be performed in parallel with the subsequent steps of this printing processing routine. it can.

  Here, the description of the print processing routine is interrupted, and the inspection target nozzle setting routine will be described. FIG. 6 is a flowchart illustrating an example of an inspection target nozzle setting routine executed by the CPU 72 of the controller 70.

  When this inspection target nozzle setting routine is executed, the CPU 72 first sets a variable p indicating the number of passes of the inspection target nozzle before image formation to an initial value 1 (step S300). Then, it is determined whether or not the variable p is a value 1 (step S310). If a positive determination is made, the inspection target maximum nozzle number Nmax is set to a value N1 (step S320), and if a negative determination is made, inspection is performed. The target nozzle maximum number Nmax is set to the value N2 (step S330). Here, the inspection target nozzle maximum number Nmax is the maximum number of inspection target nozzles that can be inspected before the image formation of the p-th pass. As described above, since the number of nozzles that can be inspected is different between the nozzle inspection before the first pass image formation and the nozzle inspection before the second pass image formation, when the variable p is 1, the value of Nmax is set. When N1 is set and the variable p is 2 or more, Nmax is set to the value N2.

  Subsequently, the CPU 72 waits until the p-pass image data is stored in the print buffer area of the RAM 74 (step S340), and identifies the nozzle used in the p-pass based on the stored p-pass image data. (Step S350). Here, the nozzle used in the p-th pass will be described. The p-pass use nozzle is a nozzle that discharges ink onto the recording paper S in the p-pass image formation among the nozzles 23. An explanatory diagram of the nozzle used is shown in FIG. FIG. 7 shows a state in which an image for one pass is formed by dots formed by ejecting ink from nozzles. In FIG. 7, for convenience of explanation, it is assumed that the nozzle row includes 10 nozzles of n = 1 to 10, and large / medium / small dots are not distinguished, and only the presence / absence of dots is shown. The nozzles that eject ink even once in the image formation for one pass in FIG. 7, that is, the nozzles of n = 1, 3, 4, 5, 9, 10 are used nozzles. The CPU 72 reads out the p-pass image data from the image data stored in the print buffer area, converts this image data into print data that indicates which nozzles in the nozzle array 68 form which dot, Based on the printing data, it is possible to specify the nozzle used in the p-th pass.

  Then, it is determined whether or not the number of used nozzles Nu (p) in the p-pass specified in step S350 is equal to or less than the inspection target maximum nozzle number Nmax (step S360). Are used as inspection target nozzles before image formation in the p-th pass (step S370). Specifically, the setting of the inspection target nozzle before the p-pass image formation is performed by specifying information for specifying the inspection target nozzle (for example, information indicating the number of nozzles in the nozzle array 68) before the p-pass image formation. This is performed by storing the inspection target nozzle in the inspection target nozzle storage area of the RAM 74. On the other hand, if a negative determination is made in step S360, the inspection target nozzle maximum number Nmax among the used nozzles in the p-pass is set as the inspection target nozzle before the p-pass image formation (step S380). When Nmax inspection target nozzles are set from Nu (p) nozzles, the nozzles that have never been set as inspection target nozzles in the current inspection target nozzle setting routine are set as the inspection target nozzles with the highest priority. Then, a plurality of continuous nozzles are preferentially set as inspection target nozzles. For example, when the maximum number Nmax of inspection target nozzles in FIG. 7 is 3, and no nozzles of n = 1 to 10 have been set as inspection target nozzles, n = 3, which is a plurality of continuous nozzles. The nozzles 4 and 5 are set as inspection target nozzles. In the present embodiment, a plurality of continuous nozzles means a plurality of nozzles where there are portions where dots of ink ejected by each nozzle are continuous in the sub-scanning direction. Accordingly, among the nozzles used, the nozzles with n = 3, 4, and 5 are regarded as a plurality of continuous nozzles because there are portions where the dots are continuous in the sub-scanning direction, and the nozzles with n = 9 and 10 have dots in the sub-scanning direction. Since there is no continuous part, it is not regarded as a plurality of continuous nozzles. The plurality of continuous nozzles can be specified based on the printing data in the same manner as when the used nozzle is specified in step S350.

  When the inspection target nozzles before the image formation for the p-th pass are set in step S370 or S380, it is determined whether or not the inspection target nozzles before the image formation for all passes are set (step S390), and a negative determination is made. Then, the variable p is incremented by 1 (step S400), the process proceeds to step S310, and the processes of steps S310 to S400 described above are repeated. On the other hand, if a positive determination is made in step S390, this routine ends. By executing this inspection target nozzle setting routine, inspection target nozzles are set for each timing before image formation in each pass from the first pass to the last pass. An example of the inspection target nozzle stored in the inspection target nozzle storage area of the RAM 74 is shown in FIG. As shown in the drawing, in the inspection target nozzle storage area, information for specifying the inspection target nozzles before image formation in each pass is sequentially stored from the first pass.

  Returning to the description of the print processing routine in FIG. When the process of step S120 is executed, the CPU 72 sets a variable s indicating how many passes are to be printed next to an initial value 1 (step S130), and switches any one of the voltage application circuits 53 and 153. SW is turned on (step S140). Specifically, if the variable s is an odd number, the next nozzle row 68 is in the inspection region 52, so the switch SW of the voltage application circuit 53 is turned on. If the variable s is an even number, the next nozzle row Since 68 is opposed to the inspection region 152, the switch SW of the voltage application circuit 153 is turned on. As a result, a voltage (400 V) is applied between the print head 24 and one of the electrode members 42 and 142. Subsequently, the process waits until the nozzle row 68 moves to an area facing either of the inspection areas 52 and 152 (step S150). That is, if the variable s is an odd number, it waits until it moves to the area facing the inspection area 52, and if the variable s is an even number, it waits until it moves to the area facing the inspection area 152. Then, the mask circuit 64 of the print head 24 discharges ink from any one of the nozzles to be inspected before the image formation of the s-th pass stored in the inspection target nozzle setting routine described above. And the piezoelectric element 66 is controlled (step S160). For example, when the stored inspection target nozzle is FIG. 8 and the variable s has a value of 1, n = 5, 6, 10,... Which are inspection target nozzles before the first pass image formation. Ink is ejected from any one of the nozzles. Then, it is determined whether or not the level (amplitude) of the output signal waveform between the print head 24 and one of the electrode members 42 and 142 at that time is greater than or equal to the threshold value Vthr (step S170). Specifically, in step S140, the output signal waveform between the electrode member to which the SW is turned on and the voltage is applied and the print head 24 is determined.

  Here, the principle of nozzle inspection will be described. Since this principle is the same for both inspection apparatuses 50 and 150, nozzle inspection by the inspection apparatus 50 will be described, and description of the inspection apparatus 150 will be omitted. An experiment was conducted in which an ink droplet was ejected from the nozzle 23 in a state where a potential difference was generated between the print head 24 and the electrode member 42 by grounding the print head 24. The output signal waveform appeared as a sine curve. It is considered that the principle that such an output signal waveform is obtained is that an induced current flows due to electrostatic induction as a charged ink droplet is ejected to the electrode member 42. In addition, the amplitude of the output signal waveform output from the voltage detection circuit 54 tends to increase as the distance from the print head 24 to the electrode member 42 decreases, and also increases as the flying ink droplet increases. It was. For this reason, when the nozzle 23 is clogged and the ink droplet does not fly or the ink droplet is smaller than a predetermined size, the amplitude of the output signal waveform is smaller than that at the normal time or becomes almost zero, so the output signal waveform Whether or not the nozzle 23 is clogged can be determined based on whether or not the amplitude is less than a predetermined threshold value Vthr. Here, even if the ink droplet has a predetermined size, since the amplitude of the output signal waveform by the ink droplet for one shot is weak, a large number of ink droplets (e.g., the operation of ejecting a large dot is performed eight times) In addition to discharging, the signal is amplified by the inverting amplifier circuit 54b. Therefore, the output signal can be an integrated value of a large number of ink droplets, and a sufficiently large output signal waveform can be obtained from the voltage detection circuit 54. The number of ink ejections can be arbitrarily set so as to be the number of ejections that can ensure inspection accuracy. The threshold value Vthr can be set empirically so that the ejection of ink droplets can be determined.

  When the output level is less than the threshold value Vthr in step S170, it is considered that a discharge failure such as clogging has occurred in the nozzle that has discharged ink this time, and information for specifying the nozzle (for example, the number of the nozzle in the nozzle row 68). (Information shown) is associated with the value of the variable s and stored in the ejection failure nozzle storage area of the RAM 74 (step S180). After step S180 or when the output level is equal to or higher than the threshold value Vthr in step S170 (that is, when the nozzle that ejected ink this time is normal), the CPU 72 sets the nozzles for all the inspection target nozzles before the image formation of the s pass It is determined whether or not an inspection has been performed (step S190). If a negative determination is made, the process proceeds to step S150, and the processes of steps S150 to S190 are repeated. When nozzle inspection is performed for all of the inspection target nozzles before the image formation in the s pass, a positive determination is made in step S190, and the switch SW that is turned on in step S140 of the voltage application circuits 53 and 153 is determined. Is turned off (step S200). When the variable s is 1, the nozzle inspection before the first pass image formation is all completed while the nozzle row 68 passes through the region facing the inspection region 52 once. After the determination is made, a negative determination is not made in step S150 while the processes in steps S150 to S190 are repeated. On the other hand, when the variable s is equal to or greater than 2, the nozzle array 68 passes once through the area facing either the inspection area 52 or 152 while repeating the processes of steps S150 to S190, and a negative determination is made in step S150. In step S150, the carriage 22 moves and the nozzle array 68 is opposed to one of the inspection areas 52 and 152 for the second time, and then the processes in steps S150 to S190 are repeated. When the variable s is 2 or more, the nozzle inspection for all the inspection target nozzles is completed in two steps in this way.

  If the process of step S200 is performed, it is subsequently determined whether any of the inspection target nozzles before the image formation of the s pass is a defective ejection nozzle (step S210). Specifically, this determination is performed based on whether or not there is a nozzle stored in association with the value of the variable s in the ejection failure nozzle storage area of the RAM 74 in step S180. If a negative determination is made, the process waits until the nozzle 23 of the print head 24 started to move in step S120 described above moves to the image forming area described above (step S220). Is controlled to eject ink from the nozzles 23 based on the s-pass image data stored in, and an s-pass image is formed on the recording paper S (step S230). Specifically, the s-pass image data is read from the image data stored in the print buffer area, and this image data is used for printing data indicating which nozzles in the nozzle array 68 form large, medium, and small dots. And the print head 24 is controlled to eject ink from the nozzles 23 in accordance with the print data. The printing data converted in step S350 described above may be stored in the RAM 74 and used in step S230. Then, it is determined whether or not printing of all passes has been completed (step S240). This determination is made based on, for example, whether or not the storage of the image data started in step S100 has been completed and printing of all stored passes has been completed. If a negative determination is made in step S240, the variable s is incremented by 1 to perform image formation for the next pass (step S250), and the above-described processing in steps S140 to S250 is repeated to perform nozzle inspection and each pass image. Repeat the formation. If an affirmative determination is made in step S240, the carriage motor 34a is controlled to move the carriage 22 to the home position, and the paper feed roller 35 and a paper discharge roller (not shown) are controlled to discharge the recording paper S. (Step S260), this routine is finished.

  On the other hand, if an affirmative determination is made in step S210, it is determined in step S180 whether or not there are a plurality of continuous nozzles among the ejection failure nozzles stored in the ejection failure nozzle storage area of the RAM 74 in association with the variable s. Determination is made (step S270). Note that whether there are a plurality of continuous nozzles can be determined based on the printing data, as in step S380 described above. If an affirmative determination is made in step S270, an error message indicating that printing is stopped due to defective nozzle ejection is transmitted to the user PC 110 via the I / F 79 to notify the user (step S280), and the printing is completed. The process of step S260 is executed without waiting, and this routine is terminated. When performing image formation by the band method, when two or more continuous nozzles fail to be ejected, the image quality of printing becomes noticeable, so printing is stopped on the spot. On the other hand, if a negative determination is made in step S270, an error message indicating that there is a nozzle ejection failure is transmitted to the user PC 110 via the I / F 79 to notify the user (step S290), and the process proceeds to step S220. When there is no noticeable deterioration in the image quality of printing, only the user is notified and printing is continued. When the user confirms the notification in step S290 and wants to cancel printing, the user PC 110 is operated to instruct the printer 20 to cancel printing. When the CPU 72 receives the print cancel instruction via the I / F 79, the print processing routine is forcibly terminated.

  Here, the correspondence between the components of the present embodiment and the components of the present invention will be clarified. The printer 20 of this embodiment corresponds to the fluid ejection device of the present invention, the nozzle 23 corresponds to a plurality of nozzles, the print head 24 corresponds to the head, and the carriage motor 34a, the driven roller 34b, and the carriage belt 32 reciprocate the head. The nozzle inspection device 50 corresponds to the inspection means, the CPU 72 corresponds to the control means, and the RAM 74 corresponds to the storage means. In the present embodiment, an example of the control method of the fluid ejection device of the present invention is also clarified by describing the operation of the printer 20.

  According to the embodiment described in detail above, the CPU 72 controls the print head 24 and the carriage motor 34a, and the nozzle 23 of the print head 24 moves from the nozzle 23 in the image forming area while moving once in the forward or backward path of the movable area. An image for one pass is formed by ejecting ink onto the recording paper S, and when forming an image on the recording paper S by performing image formation for one pass multiple times, an inspection target nozzle setting routine is executed, Of the nozzles 23, the number of nozzles that can be inspected by the nozzle inspection apparatus 50 while the print head 24 moves between the inspection areas 52 and 152 in the non-image forming area between passes. The nozzles within the maximum number Nmax of the inspection target nozzles are the inspection target nozzles that are the target of the nozzle inspection for inspecting whether or not the fluid is normally discharged from the nozzles. It is set to successive Le. Then, by executing the processing in steps S140 to S200, the nozzle 23 of the print head 24 moves between the passes while moving the region facing the inspection regions 52 and 152 in the non-image forming region. The print head 24 and the nozzle inspection device 50 are controlled to perform the nozzle inspection of the nozzles. As a result, the nozzle 23 of the print head 24 moves between the areas facing the inspection areas 52 and 152 in the non-image forming area between the passes during image formation, and within the maximum number Nmax of inspection target nozzles. Since the nozzle inspection is performed only for the set inspection target nozzle, the movement of the head is never stopped for the nozzle inspection. Therefore, nozzle inspection can be performed without increasing the time required for image formation. In setting the inspection target nozzle, the used nozzle, which is a nozzle that discharges ink onto the recording paper S in the next one-pass image formation, is set as the inspection target nozzle. Therefore, in the next one-pass image formation, Can inspect nozzles that affect image quality degradation. Furthermore, when the number of used nozzles is larger than the inspection target nozzle maximum number Nmax, in order to set the nozzle that has never been set as the inspection target nozzle in the current inspection target nozzle setting routine as the inspection target nozzle with the highest priority, More different nozzles can be inspected among the nozzles that affect image quality degradation. Furthermore, since a plurality of nozzles that are consecutively set next to nozzles that have never been set as inspection target nozzles are set as inspection target nozzles, ejection of two or more continuous nozzles in which deterioration in image quality becomes noticeable The presence or absence of defects can be determined efficiently.

  It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that the present invention can be implemented in various modes as long as it belongs to the technical scope of the present invention.

  For example, in the above-described embodiment, in step S380 of the inspection target nozzle setting routine, among the used nozzles used in the next pass image formation, a plurality of consecutive nozzles are preferentially set as inspection target nozzles. , It is not necessary to give priority to a plurality of continuous nozzles. In addition, a plurality of continuous nozzles means a plurality of nozzles where there are portions where dots of ink ejected by each nozzle are continuous in the sub-scanning direction. For example, n = 9 in FIG. , 10 nozzles may be regarded as a plurality of continuous nozzles, and all the nozzles that are simply continuous among the used nozzles may be used as a plurality of continuous nozzles. Further, the used nozzles in step S350 are not specified, and a plurality of nozzles that are continuous in the nozzle row 68 may be simply replaced with a plurality of nozzles. In this case, a plurality of nozzles that are continuous within the inspection target nozzle maximum number Nmax may be preferentially set as the inspection target nozzle. For example, a plurality of Nmax consecutive nozzles in order from the nozzle of n = 1 in the nozzle array 68 are set as inspection targets, and nozzles up to n = 180 nozzles are formed during image formation of a plurality of passes. It is good also as what inspects.

  In the embodiment described above, in step S380, the nozzle that has never been set as the inspection target nozzle in the current inspection target nozzle setting routine is set as the inspection target nozzle with the highest priority. However, such a nozzle is prioritized. Not necessary. For example, a plurality of continuous nozzles may be set as inspection target nozzles with the highest priority.

  In the embodiment described above, all the used nozzles in the p-pass are set as inspection target nozzles before the image formation in the p-pass in step S370, but the number Nu (p) of all the used nozzles in the p-pass. Is smaller than the maximum number Nmax of inspection target nozzles, the other nozzles may be further set as inspection target nozzles by the number Nmax−Nu (p). In this case, when the image data after the p + 1th pass is stored in the print buffer area, the used nozzles after the p + 1th pass are specified in the same manner as in step S350, and the specified nozzle is given priority by Nmax−Nu ( The number of nozzles to be inspected may be the same as the number p). In this way, when the number of nozzles used in the p-th pass is small, it is possible to inspect in advance the nozzles that affect the image quality degradation in the image formation of the pass after the p + 1-th pass.

  In the embodiment described above, the printer 20 forms an image on the recording sheet S by the band method, but may form an image by another method. For example, an area in which the nozzle row 68 passes over the recording paper S in one pass when the paper feed roller 35 transports the recording paper S by a distance equal to or less than the length in the transport direction of the nozzle row 68 between each pass. However, it is also possible to form an image in an interlaced manner in which there is an overlap between passes. Further, the band method and the interlace method may be selectively used according to the type of the recording paper S and the image data. For example, an image may be formed by a band method for printing on plain paper or characters, and an image may be formed by an interlace method for printing on photographic paper or image data compressed by JPEG. In this case, a plurality of continuous nozzles may be preferentially set as inspection target nozzles only when printing in the band method, and the use nozzles may be simply set as inspection target nozzles when printing in the interlace method. .

  In the above-described embodiment, storage of image data in the print buffer area in step S100 and execution of the inspection target nozzle setting routine in step S110 are performed almost simultaneously. However, storage of image data in the print buffer area is performed. It is good also as what progresses to step S110 after all are completed. The print buffer area only needs to store image data for at least one pass of the image data. If the print buffer area can only store image data for one pass, when image data storage is started in step S100, only the image data for one pass is stored in the print buffer area, and for one pass stored in step S230. After the image based on the image data is formed on the recording paper S, the image data for the next one pass may be overwritten with the image data for the previous one pass and stored in the print buffer area.

  In the embodiment described above, printing is stopped only when it is determined in step S270 that there are continuous defective nozzles. However, when it is determined in step S210 that there are defective nozzles, the process proceeds to step S280 and printing is stopped. May be. In addition, when it is determined in step S270 that there are continuous ejection failure nozzles, printing is not stopped, the user is notified that noticeable image quality degradation has occurred, and the process proceeds to step S220 to continue printing. It is good. Furthermore, when an affirmative determination is made in step S210 or step S270, the carriage 22 may be moved to the home position to perform cleaning, thereby eliminating nozzle ejection defects and continuing printing. Furthermore, when an affirmative determination is made in step S210 or step S270, flushing is performed to control the piezoelectric element 66 so that ink is ejected from the ejection failure nozzle a plurality of times in the flushing box 40, and printing is continued if the ejection failure is resolved. It is good also as what to do. Furthermore, when an affirmative determination is made in step S210 or step S270, the ink that should be ejected from the ejection failure nozzle may be ejected from another normal nozzle. This is because, for example, by adjusting the distance that the recording paper S is transported between passes, the other normal nozzles face the area on the recording paper S that should normally pass by facing the defective ejection nozzles. Then, the image may be formed so as to pass through.

  In the embodiment described above, image formation for one pass is performed by ejecting ink from the nozzles 23 to the recording paper S in the image forming region while the carriage 22 moves once in the forward or backward path of the movable region. However, image formation for one pass may be performed only while moving on one of the forward path and the return path, and image formation may not be performed while moving the other. In this case, only one of the inspection areas 52 and 152 may be provided.

  In the above-described embodiment, the inspection areas 52 and 152 are disposed so as to face a part of the non-image forming area as shown in FIG. 4, but the inspection area 52 is not limited to this. The inspection area 152 may be disposed so as to face the entire area between the positions b and c of the area and to face the entire area between the positions d and e of the non-image forming area. Further, the inspection areas 52 and 152 may be movable on the platen 29 in the main scanning direction. Further, a similar inspection area may be provided in addition to the inspection areas 52 and 152. FIG. 9 shows the relationship between the carriage 22 and each inspection area when the inspection areas 52a and 152a are provided on the center side of the platen 29 with respect to the inspection areas 52 and 152. FIG. 9A shows a case where the recording paper S has the same size as that in FIG. 4, and the image forming area and the non-image forming area of the nozzle 23 are the same as those in FIG. When an image is formed on the recording paper S of this size, as shown in the figure, the inspection areas 52a and 152a are at positions facing the image forming area, and the recording paper S is placed, so no nozzle inspection is performed. As described with reference to FIG. 4, the nozzle inspection is performed in the inspection regions 52 and 152. On the other hand, when the recording paper S is smaller than FIG. 4 as shown in FIG. 9B, the position of the nozzle 23 is between the positions g and h shorter than the positions c and d according to the size of the recording paper S. It becomes an image forming area. Further, since the distance required for acceleration for moving the carriage 22 at the speed V1 and deceleration after moving at the speed V1 is not different from that in FIG. 9A, the distance between the positions f and g in FIG. 9 (a) is the same distance between the positions b and c, and the positions h and i in FIG. 9 (b) are the same distances as the positions d and e in FIG. 9 (a). Therefore, when forming an image on the recording paper S in FIG. 9B, the carriage 22 moves between the positions a and i to form the first pass image between the positions g and h, and the second pass and thereafter. Reciprocates between positions f and i to form an image for one pass between positions g and h. Therefore, the nozzle inspection before the image formation in the first pass is performed while the nozzle 23 moves in the region facing the inspection regions 52 and 52a, and the nozzle inspection before the image formation in the second pass is performed by the nozzle 23. This is performed while moving the area facing either one of the areas 52a and 152a. As described above, if a plurality of inspection areas are selectively used, nozzle inspection can be performed without increasing the time required for image formation even when printing is performed on recording papers having different sizes.

  In the embodiment described above, the print head 24 can reciprocate in the main scanning direction, but can also move in the vertical direction (thickness direction of the recording paper S), and the platen 29 according to the thickness of the recording paper S. And the print head 24 (platen gap, hereinafter referred to as PG) may be adjustable. In this case, the nozzle inspection devices 50 and 150 can adjust the gap (sensor gap, hereinafter referred to as SG) between the electrode members 42 and 142 and the print head 24 by adjusting the height of the electrode members 42 and 142 with respect to the platen 29. It may be a thing. FIG. 10 shows how PG and SG are adjusted by the PG adjusting mechanism 80 for adjusting PG and the SG adjusting mechanism 90 for adjusting SG. As shown in the figure, the PG adjusting mechanism 80 has a rotatable shaft 81 disposed below the carriage shaft 28 in parallel with the carriage shaft 28, and both ends of the shaft 81 so that the cam surface contacts the lower side of the carriage shaft 28. PG adjustment cams 82 (shown only on one side) attached to each. Then, by rotating the shaft 81 and the PG adjusting cam 82 by a PG adjusting motor (not shown) to move the carriage shaft 28 up and down to adjust the height of the print head 24, the PG can be adjusted. Yes. The SG adjusting mechanism 90 is provided below the flushing box 40, a spring 92 that is placed on the base 91 and biases the flushing box 40 upward, guides 93 a and 93 b that instruct the outer periphery of the flushing box 40 to be slidable. SG adjusting cam 95 rotatably supported by a rotatable shaft 94 in the working chamber 40b. The pedestal 91 and the shaft 94 are fixed independently of the flushing box 40 and the working chamber 40b. Has been. Then, by rotating the shaft 94 and the SG adjusting cam 95 by an SG adjusting motor (not shown), the distance between the cam surface contacting the floor surface of the working chamber 40b and the shaft 94 changes, whereby the guides 93a and 94b are changed. The flushing box 40 moves vertically along the vertical direction so that the SG can be adjusted. In this way, even when the PG adjusting mechanism 80 changes the PG according to the thickness of the recording paper S, the SG adjusting mechanism 90 can maintain the SG suitable for the nozzle inspection. Also in FIG. 10, PG is different between FIG. 10 (a) and FIG. 10 (b), but SG is the same. If the SG adjusting mechanism 90 is not provided, the PG adjusting mechanism 80 adjusts both PG and SG. When the print head 24 passes through the area facing the inspection area 50, the print head 24 There is a case where the height of the print head 24 needs to be changed when passing through the image forming area. Therefore, an extra time is required to change the height of the print head 24 during printing during one pass, and the printing time increases. If the SG adjustment mechanism 90 as shown in FIG. 10 is provided, SG suitable for nozzle inspection can be maintained without increasing the printing time.

  In the above-described embodiment, the print head 24 is provided with the nozzle array 68 in which the plurality of nozzles 23 for ejecting black (K) ink are arranged as shown in FIG. It is good also as what is provided. For example, as shown in FIG. 11, a plurality of nozzles 23C, 23M, 23Y, and 23K that discharge inks of cyan (C), magenta (M), yellow (Y), and black (K) are arranged for each color. The nozzle rows 68C, 68M, 68Y, and 68K may be provided. In this case, the ink cartridge 26 individually accommodates each color ink of cyan (C), magenta (M), yellow (Y), and black (K) containing pigment or dye as a colorant in water as a solvent. What should I do? When a plurality of nozzle rows are provided as shown in FIG. 11, the inspection target nozzle setting routine described above is executed for each nozzle row to set inspection target nozzles, and steps S150 to S190 of the print processing routine are repeated. The nozzle inspection process may be repeated for each nozzle row.

  In the above-described embodiment, the nozzle inspection is performed using the voltage change between the print head 24 and the electrode member 42 accompanying the ink ejection, but the nozzle inspection may be performed using a laser beam. That is, a light emitting element 102 and a light receiving element 104 are installed in the flushing box 40 as shown in FIG. 12, and laser light emitted from the light emitting element 102 and incident on the light receiving element 104 and ink ejected from a predetermined nozzle 23 are provided. After the print head 24 is arranged at a position where the nozzles intersect, and the ink is ejected from the nozzle 23, it is determined whether the laser beam is blocked by the ink based on the output signal of the light receiving element 104, and the block In this case, it is assumed that ink is actually ejected from the nozzle 23. Thereafter, the print head 24 is arranged at a position where the ink and the light beam ejected from the next nozzle 23 intersect, and it is inspected whether the ink is actually ejected in the same manner as before. Even in this case, it is possible to inspect nozzles using ink. Details of such an inspection method are disclosed in JP-A-2005-35309.

  In the embodiment described above, the electrode member 42 in the flushing box 40 is disposed on the upper surface of the ink absorbing member 41, but it may be disposed so as to be sandwiched between the middle stages of the ink absorbing member 41. In this case, the ink absorbing member 41 may be conductive, but the ink absorbing member 41 may be non-conductive because the ink is water-soluble and conductive. Further, the ink absorbing member 41 may not be provided. Further, as shown in FIG. 13, instead of the electrode member 42, an electrode member 242 is provided in the vicinity of the position where the ink ejected from the nozzle 23 passes, and this occurs when the ink passes in the vicinity of the electrode member 242. The electrical change may be detected by the voltage detection circuit 54, and the ink ejection state may be detected based on the detection result. The electrode member 242 may be an electrode plate or an electric wire as long as it can detect an electrical change accompanying the passage of ink.

  In the above-described embodiment, the print head 24 is connected to the ground and a voltage is applied to the electrode member 42 to generate a potential difference between the print head 24 and the electrode member 42. However, the electrode member 42 is connected to the ground. The voltage difference may be generated between the print head 24 and the electrode member 42 by applying a voltage to the print head 24. Further, the potential of the electrode on the side connected to the ground is not limited to the ground but may be a potential that is different from the voltage of the voltage application circuit 53 and gives a predetermined potential difference with the voltage of the voltage application circuit 53. Good. Note that the electrode that applies a predetermined potential in the print head 24 may be any electrode that can conduct the ink in the print head 24 and apply a potential to the ink, such as a nozzle plate or an electrode in the head.

  In the above-described embodiment, both the circuits 53 and 54 are connected to the electrode member 42. However, both the circuits 53 and 54 are connected to the print head 24, or one of the circuits 53 and 54 is connected to the electrode member 42 and the print head. The other of the circuits 53 and 54 may be connected to the other of the electrode member 42 and the print head 24.

  In the above-described embodiment, the print head 24 applies a voltage to the piezoelectric element 66 and deforms the piezoelectric element 66 to pressurize the ink. However, the ink is applied to the heating resistor (for example, a heater) by applying a voltage. A method may be employed in which the ink is pressurized with bubbles generated by heating. The ink cartridge 26 is configured as a so-called on-carriage mounted on the carriage 22 that reciprocates, but may be configured as a so-called off-carriage that is mounted on the housing 39 and supplies ink or the like to the print head 24 through a tube.

  In the embodiment described above, an example in which the present invention is embodied in the printer 20 that ejects ink onto the recording paper S has been described. However, the present invention can be applied without being limited thereto. For example, it may be a printing device that discharges a liquid (dispersion) in which particles of liquid other than ink or functional material are dispersed, a fluid such as a gel, or a solid that can be discharged as a fluid. The present invention may be embodied in a printing apparatus that discharges. For example, a liquid discharge device that discharges a liquid in which a material such as an electrode material or a color material used for manufacturing a liquid crystal display, an EL (electroluminescence) display, a surface emitting display, and a color filter is dissolved, or a liquid material in which the material is dispersed It is good also as a liquid discharge apparatus which discharges the liquid used as a liquid material discharge apparatus which discharges, and a sample used as a precision pipette. Also, a liquid ejection device that ejects a transparent resin liquid such as an ultraviolet curable resin on a substrate to form a micro hemispherical lens (optical lens) used for an optical communication element or the like, a fluid ejection device that ejects a gel, A powder discharge type recording apparatus that discharges powder such as toner may be used.

  In the embodiment described above, the printer 20 has been described as the fluid ejection device of the present invention. However, a multifunction printer including a scanner unit capable of reading a document or a FAX device having a FAX function may be used.

  20 printer, 21 printing mechanism, 22 carriage, 23, 23C, 23M, 23Y, 23K nozzle, 24 print head, 25 linear encoder, 26 ink cartridge, 28 carriage shaft, 29 platen, 30 paper feed mechanism, 31 capping device, 32 Carriage belt, 33 Drive motor, 34a Carriage motor, 34b Driven roller, 35 Paper feed roller, 39 Housing, 40 Flushing box, 41 Ink absorbing member, 42, 142, 242 Electrode member, 43 Cap, 43a Support rod, 45 Electrode pin, 50, 150 Nozzle inspection device, 51 Circuit case, 52, 52a, 152, 152a Inspection region, 53 Voltage application circuit, 54, 154 Voltage detection circuit, 54a Integration circuit, 54b Inversion amplification circuit, 5 c A / D conversion circuit, 60 head drive waveform generation circuit, 62 head drive board, 63 flat cable, 64 mask circuit, 66 piezoelectric element, 68, 68C, 68M, 68Y, 68K nozzle array, 70 controller, 72 CPU, 73 Flash ROM, 74 RAM, 79 Interface (I / F), 80 PG adjustment mechanism, 81 shaft, 82 PG adjustment cam, 90 SG adjustment mechanism, 91 pedestal, 92 spring, 93a, 93b guide, 94 shaft, 95 SG Adjustment cam, 102 light emitting element, 104 light receiving element, 110 user personal computer, R1 resistance element, S recording paper, SW switch.

Claims (8)

A head having a plurality of nozzles and discharging fluid from the nozzles toward the target while moving in the main scanning direction;
The head is reciprocated within a movable region provided in the main scanning direction including an image forming region in which the head discharges fluid to the target and a non-image forming region in which the head does not discharge fluid to the target. A head reciprocating means;
Inspection means for performing nozzle inspection for inspecting whether fluid is normally discharged from the nozzle;
By controlling the head and the head reciprocating means so that the head moves once in the forward or backward path of the movable area, the fluid is discharged from the nozzle to the target in the image forming area for one pass. When forming an image on the target by performing image formation for one pass a plurality of times and forming the image on the target, the head is located in the non-image formation region between the passes among the plurality of nozzles. Nozzles within the inspectable number, which is the number of nozzles that can be inspected by the nozzle, are sequentially set as inspection target nozzles to be subjected to the nozzle inspection, and between the passes, Control means for controlling the inspection means to perform the nozzle inspection of the inspection target nozzle while the head moves in the non-image forming region;
A fluid ejection device comprising: The fluid ejection device according to claim 1,
Storage means capable of storing image data representing an image for the next one pass formed on the target;
With
The control unit identifies a nozzle that discharges fluid to the target in the next one-pass image formation based on the image data read from the storage unit, and preferentially sets the nozzle as the inspection target nozzle. Is a means to
Fluid ejection device. The head is a head having a nozzle row in which a plurality of the nozzles are formed in a direction substantially orthogonal to the main scanning direction,
The control means, when forming an image on the target, reciprocates the head and the head so as to perform image formation in a band system in which a region where fluid can be discharged onto the target in one pass does not overlap between the passes. In controlling the moving means and setting the inspection target nozzle, the nozzle that discharges fluid to the target in the next one-pass image formation, and a plurality of continuous nozzles in the nozzle row are the inspection target. It is a means to preferentially set the nozzle,
The fluid ejection device according to claim 2. The storage means is means capable of storing image data representing an image for at least two passes after the next to be formed on the target,
The control means can identify a nozzle that ejects fluid in the next and subsequent image formations among the current image formations on the target based on the image data read from the storage means, and more than the inspectable number. When the number of nozzles that are preferentially set as inspection target nozzles is small, in addition to the nozzles that are preferentially set as inspection target nozzles, the nozzles that discharge fluid in the subsequent and subsequent pass image formation are preferentially set. Means for setting the nozzle to be inspected;
The fluid ejection device according to claim 2 or 3. When the number of nozzles that ejects fluid to the target in the image formation for the next specified one pass is larger than the inspectable number, the control unit is configured to image the same target among the specified nozzles. It is means for setting a nozzle that has never been set as the inspection target nozzle to the inspection target nozzle with the highest priority during formation.
The fluid ejection device according to any one of claims 2 to 4. The head is a head having a nozzle row in which a plurality of the nozzles are formed in a direction substantially orthogonal to the main scanning direction,
When forming an image on the target, the control means reciprocates the head and the head so as to perform image formation in a band system in which fluid discharge areas on the target do not overlap between the passes in one pass. In controlling the moving means and setting the inspection target nozzle, it is means for preferentially setting a plurality of continuous nozzles in the nozzle row to the inspection target nozzle
The fluid ejection device according to claim 1. The control means is means for not setting the same nozzle as the inspection target nozzle again while there is a nozzle that has not been subjected to the nozzle inspection even once during image formation on the same target.
The fluid ejection device according to claim 6. A head having a plurality of nozzles that discharges fluid from the nozzles toward the target while moving in the main scanning direction, an image forming region in which the head discharges fluid to the target, and the head discharges fluid to the target A head reciprocating means for reciprocating the head within a range of a movable region provided in the main scanning direction including a non-image forming region that does not perform, and a nozzle for inspecting whether fluid is normally ejected from the nozzle A control method of a fluid ejection device provided with inspection means for performing inspection,
By controlling the head and the head reciprocating means to move the head once in the forward or backward path of the movable area, the fluid is discharged from the nozzle to the target in the image forming area for one pass. When forming an image on the target by performing image formation for one pass a plurality of times and forming the image on the target, the head is located in the non-image formation region between the passes among the plurality of nozzles. The nozzles within the inspectable number, which is the number of nozzles that can be inspected by the inspection means, are sequentially set as the inspection target nozzles to be subjected to the nozzle inspection, and Controlling the inspection means to perform the nozzle inspection of the inspection target nozzle while the head moves in the non-image forming region;
Control method for fluid ejection device including