JP6544083B2 - Ink jet recording apparatus, control method of ink jet recording apparatus, and control program of ink jet recording apparatus - Google Patents

Description

  The present invention relates to an inkjet recording apparatus, a control method of the inkjet recording apparatus, and a control program of the inkjet recording apparatus.

  2. Related Art There is known an ink jet recording apparatus which is an image forming apparatus of a liquid discharge recording type using a recording head which discharges droplets (ink droplets). In an inkjet recording apparatus, droplets of ink are discharged from a nozzle of a recording head to a recording medium (also referred to as recording material, paper, or recording paper) to perform image formation (recording, printing, printing is also used synonymously) . As an inkjet recording device, a serial type inkjet recording device and a line type inkjet recording device are widely known.

  The serial type inkjet recording apparatus performs printing by combining an operation of discharging droplets while moving the recording head in the main scanning direction (width direction) with respect to the recording medium, and an operation of moving the recording medium in the sub scanning direction. To do.

  On the other hand, the line type inkjet recording apparatus has a line head having a printing width corresponding to the width of a recording sheet as a recording head, and performs printing while relatively moving the line head and the recording medium. In recent years, line-type ink jet recording apparatuses have increased in printing speed and image quality, and demand in the commercial and industrial fields has increased.

  In addition, there is also known a line-type inkjet recording apparatus that uses a continuous long recording medium (continuous paper) as a recording medium. Such an apparatus carries out printing at high speed by conveying the continuous paper wound in a roll, and is suitable for mass printing.

  In these inkjet recording apparatuses, image defects may occur if droplets are not ejected properly from the nozzles. On the other hand, for example, Patent Document 1 includes a plurality of droplet discharge heads, discharge abnormality detecting means for detecting discharge abnormality of droplets from the nozzles, and recovery processing for eliminating the cause of discharge abnormality of droplets. And, when the droplet discharge head discharges droplets to the droplet receiver, discharge abnormality is detected by the discharge abnormality detection unit with respect to the discharge operation for each droplet to be discharged from the nozzle. When a discharge abnormality is detected, the droplet discharge device stops the discharge of droplets to the droplet receiver and executes recovery processing according to the cause of the discharge abnormality by the recovery means. It is disclosed.

  In the case of a serial type inkjet recording apparatus, when there is a nozzle (referred to as an abnormal nozzle) from which droplets are not ejected normally, the printing operation is stopped and maintenance is performed as described in Patent Document 1. can do. It is also possible to increase the number of scans to compensate for the loss from a normal nozzle.

  However, there is a problem that productivity is reduced when the printing operation is interrupted when an abnormal nozzle is detected.

  Further, in particular, in the case of the line type inkjet recording apparatus, since the one-pass printing is in principle, it is difficult to take measures to increase the number of scans. Further, when printing continuous paper at high speed with a line type inkjet recording device, even if an abnormal nozzle is detected during printing, printing can not be stopped to recover it.

  Therefore, an object of the present invention is to provide an inkjet recording apparatus capable of reducing image defects caused by abnormal ejection of nozzles while maintaining high productivity without interrupting the printing operation.

In order to achieve the above object, an inkjet recording apparatus according to the present invention is an inkjet recording apparatus that includes a recording head provided with a plurality of nozzles that discharge droplets, and forms an image with a predetermined resolution based on image data. And counting the number of abnormal nozzles based on the detection result of the discharge abnormality detection unit that detects whether droplets are normally discharged from the nozzles and the detection result of the discharge abnormality detection unit, and the counted abnormal nozzles And a controller configured to eject droplets from the nozzle so as to have a resolution lower than the predetermined resolution when the number of dots exceeds a threshold, and the recording head includes a droplet including a color material used for image formation. And a recording head for ejecting an additional droplet after forming an image by the recording head, the control unit comprising a recording head for ejecting the additional droplet. For, it executes control for said low resolution.

  According to the present invention, it is possible to reduce image defects caused by abnormal ejection of nozzles while maintaining high productivity without interrupting the printing operation.

It is a schematic block diagram of an inkjet recording device. FIG. 6 is a plan view of the recording head as viewed from the nozzle surface. FIG. 6 is an explanatory cross-sectional view along a liquid chamber longitudinal direction showing an example of a liquid discharge head. FIG. 6 is an explanatory cross-sectional view along the short direction of the liquid chamber of the liquid discharge head. It is a schematic block diagram which shows an example of a discharge abnormality detection part. FIG. 2 is a functional block diagram of a control unit of the inkjet recording apparatus. 5 is a flowchart illustrating an example of print processing executed by the inkjet recording apparatus. 5 is a flowchart illustrating another example of the printing process performed by the inkjet recording apparatus. It is an example of a display of the abnormal nozzle on the operation panel.

  Hereinafter, the configuration according to the present invention will be described in detail based on the embodiments shown in FIG. 1 to FIG.

(Ink jet recording device)
FIG. 1 is a side view illustrating a system configuration of a printing system 100 including an inkjet recording apparatus 10 according to the present embodiment. As shown in FIG. 1, the system configuration of the printing system 100 includes an inkjet recording device 10, a sheet feeding device 40, and a sheet discharging device 50.

  The inkjet recording apparatus 10 is an image forming apparatus that uses a continuous form paper as a recording medium in a line system, and the recording medium P which is a continuous form paper is fed from the paper feeding device 40, and the recording medium P has a plurality of guides. It is transported along the roller.

  The inkjet recording apparatus 10 includes an edge controller 11, and regulates the positions of both ends of the fed recording medium P in the width direction to shift the recording medium P in the direction orthogonal to the conveyance direction of the recording medium P. The correction suppresses the meandering of the recording medium P.

  When the recording medium P is conveyed to the position of the recording head unit 20, an image is formed by discharging droplets from the recording head unit 20.

  Here, the inkjet recording apparatus 10 using continuous paper as a recording medium in the line system is mainly used for commercial use, but it is possible to improve the fixability of the image to be formed, to impart gloss to the image, etc. For the purpose of improving the quality as printed matter, in addition to the ink droplets (color ink) containing the coloring material used for image formation, additional droplets (also referred to as overcoating agent and overcoat) of colors not affecting the image ) Are known. The additional droplets are, for example, transparent clear ink.

  In the inkjet recording apparatus 10 according to the present embodiment, as shown in FIG. 1, the recording head unit 20 is arranged along the conveyance direction of the recording medium P to be black (K), yellow (Y), cyan (C), magenta The recording heads 21k, 21c, 21m and 21y for discharging droplets of each color of (M) are provided, and the recording head 21t for discharging additional droplets (T) is provided downstream thereof. Hereinafter, the recording head 21 will be referred to unless otherwise specified.

  FIG. 2 is a plan view of the recording head 21 of the recording head unit 20 as viewed from the nozzle surface. As shown in the enlarged view in FIG. 2, each recording head 21 has a plurality of nozzles 22 arrayed in a direction (hereinafter referred to as a nozzle array direction) orthogonal to the conveyance direction of the recording medium P, and a nozzle row 23 is formed. The small heads 24 each having a plurality of nozzle rows 23 are arranged in a staggered manner in the nozzle row direction to constitute a line head.

  In the example of FIG. 2, each recording head 21 has a plurality of nozzle rows 23 and discharges droplets of the same color from the nozzle rows 23. However, the present invention is not limited to this. It is also possible to eject droplets of different colors by 23 units.

  On the downstream side of the recording head unit 20 in the conveyance direction, a heat roller 12 which is a drum-shaped heater is provided. The heat roller 12 heats the recording medium P to dry and fix the droplets of the respective colors and the additional droplets that have landed on the recording medium P conveyed at high speed.

  Further, in the vicinity of the recording head unit 20, a discharge abnormality detection unit 30 (FIG. 5) for detecting a discharge abnormality of the droplets from the nozzles 22 is provided.

  The paper discharge device 50 winds up the recording medium P after image formation. Note that various post-processing such as cutting, winding, bookbinding, and the like may be performed by a post-processing device (not shown).

(Droplet discharge head)
Next, an example of the liquid discharge head constituting the recording head 21 will be described with reference to FIGS. 3 and 4. 3 is a cross-sectional view of the head along the longitudinal direction of the liquid chamber, and FIG. 4 is a cross-sectional view of the short side of the liquid chamber of the head (the direction in which the nozzles are aligned).

  The droplet discharge head includes, for example, a channel plate 101 formed by anisotropically etching a single crystal silicon substrate, a diaphragm 102 formed by, for example, nickel electroforming joined to the lower surface of the channel plate 101, and a channel The ink is supplied to the nozzle communication passage 105, the liquid chamber 106, and the liquid chamber 106 which is a flow path in which the nozzle plate 103 joined to the upper surface of the plate 101 is joined and stacked, and the nozzles 22 which discharge droplets are communicated. An ink supply port 109 communicating with a common liquid chamber 108 is formed.

  In addition, two rows (only one row is shown in FIG. 4) of stacked piezoelectrics as electromechanical conversion elements as pressure generating means (actuator means) for deforming the diaphragm 102 to press the ink in the liquid chamber 106 An element 121 and a base substrate 122 for bonding and fixing the piezoelectric element 121 are provided. In addition, support portions 123 are provided between the piezoelectric elements 121. The support portion 123 is a portion formed at the same time as the piezoelectric element 121 by dividing and processing the piezoelectric element member, but since a drive voltage is not applied, it becomes a simple support.

  Further, an FPC cable 126 for connection to a drive circuit (drive IC) (not shown) is connected to the piezoelectric element 121.

  Then, the peripheral portion of the diaphragm 102 is joined to the frame member 130, and the frame member 130 becomes the penetrating portion 131 for housing the actuator unit formed of the piezoelectric element 121, the base substrate 122 and the like and the common liquid chamber 108. A recessed portion and an ink supply hole 132 for supplying ink from the outside to the common liquid chamber 108 are formed. The frame member 130 is formed by injection molding of, for example, thermosetting resin such as epoxy resin or polyphenylene sulfite.

  Here, the flow path plate 101 is, for example, anisotropically etching a single crystal silicon substrate with a crystal plane orientation (110) using an alkaline etching solution such as a potassium hydroxide aqueous solution (KOH) to form a nozzle communication path 105, Although the recessed part and hole part used as the liquid chamber 106 were formed, it is not restricted to a single crystal silicon substrate, Other stainless steel substrates, photosensitive resin, etc. can also be used.

  The diaphragm 102 is formed of a metal plate of nickel and is manufactured by, for example, an electroforming method (electroforming method). In addition to this, a metal plate or a bonding member between metal and a resin plate may be used. it can. The piezoelectric element 121 and the support portion 123 are adhesively bonded to the diaphragm 102, and the frame member 130 is further adhesively bonded.

  The nozzle plate 103 forms a nozzle 22 with a diameter of 10 to 30 μm corresponding to each liquid chamber 106, and is adhesively bonded to the flow path plate 101. In the nozzle plate 103, a water repellent layer is formed on the outermost surface of a nozzle forming member made of a metal member via a required layer. The surface of the nozzle plate 103 is a nozzle surface.

  The piezoelectric element 121 is a stacked piezoelectric element (here, PZT (lead zirconate titanate)) in which the piezoelectric material 151 and the internal electrode 152 are alternately stacked. An individual electrode 153 and a common electrode 154 are connected to the internal electrodes 152 drawn to alternately different end faces of the piezoelectric element 121. In this embodiment, the ink in the liquid chamber 106 is pressurized using the displacement in the d33 direction as the piezoelectric direction of the piezoelectric element 121. However, the displacement in the d31 direction is used as the piezoelectric direction of the piezoelectric element 121. The configuration may be such that the ink in the ink 106 is pressurized. In addition, one row of piezoelectric elements 121 may be provided on one base substrate 122.

  In the droplet discharge head configured as described above, for example, the voltage applied to the piezoelectric element 121 is lowered from the reference potential so that the piezoelectric element 121 contracts and the diaphragm 102 descends to expand the volume of the liquid chamber 106. Then, the ink flows into the liquid chamber 106, and then the voltage applied to the piezoelectric element 121 is increased to elongate the piezoelectric element 121 in the stacking direction, and the diaphragm 102 is deformed in the direction of the nozzle 22 to change the volume of the liquid chamber 106. By shrinking the volume, the recording liquid in the liquid chamber 106 is pressurized, and a droplet of the recording liquid is ejected (sprayed) from the nozzle 22.

  Then, by returning the voltage applied to the piezoelectric element 121 to the reference potential, the diaphragm 102 is restored to the initial position, and the liquid chamber 106 expands to generate a negative pressure. At this time, the common liquid chamber 108 to the liquid chamber The recording liquid is filled in the space 106. Therefore, after the vibration of the meniscus surface of the nozzle 22 is attenuated and stabilized, the operation shifts to the operation for the next droplet discharge.

  The method of driving this head is not limited to the above example (pull-push), and depending on the drive waveform, it is possible to perform pull or push.

(Discharge abnormality detection unit)
Next, a discharge abnormality detection unit that detects a discharge abnormality of droplets from the nozzles 22 of the recording head 21 will be described. FIG. 5 is a schematic block diagram showing an example of the ejection failure detection unit 30. As shown in FIG.

  The ejection abnormality detection unit 30 includes a light emitting unit 31 that generates a laser beam, and a light receiving unit 32 that receives the laser beam from the light emitting unit 31. The light emitting unit 31 is, for example, a laser diode (LD), and the light receiving unit 32 is, for example, a photodetector (photodetector) such as a photodiode (PD).

  The ejection abnormality detection unit 30 is provided with a light emitting unit 31 on one end side of the recording head 21 and a light receiving unit 32 on the other end side in the nozzle array direction orthogonal to the conveyance direction of the recording medium P. In the example of FIG. 5, although the example in which the light emission part 31 and the light reception part 32 are alternately provided along the conveyance direction is shown, it is not restricted to this.

  The ejection abnormality detection unit 30 applies light to the droplets or additional droplets of the color ink in flight from the light emission unit 31 in the nozzle row direction, and detects the light by the light reception unit 32 to obtain optical It is possible to detect the flying state of color ink droplets and additional droplets, and detect abnormal nozzles such as nozzle defects.

(Control unit)
FIG. 6 is a functional block diagram of the control unit 200 of the inkjet recording apparatus 10. The control unit 200 shuts off the power of the apparatus, the CPU 201 which controls the overall control of the inkjet recording apparatus 10, the ROM 202 which stores programs executed by the CPU 201 and other fixed data, the RAM 203 which temporarily stores image data and the like. Rewritable non-volatile memory (NVRAM 204) to hold data during processing, and various signal processing for image data, image processing for sorting etc., and other input / output signals for controlling the entire device And an ASIC 205.

  The control unit 200 also includes a host I / F 206 for transmitting and receiving data and signals with the host, a print control unit 207 for driving and controlling the recording head 21, and various transport mechanisms for transporting the recording medium P. And a I / O 209 for inputting detection signals from various sensors.

  The control unit 200 is also connected to an operation panel 213 as an operation unit for inputting and displaying information necessary for the apparatus, and a discharge abnormality detection unit 30 for detecting a discharge abnormality of droplets. There is.

  Further, the CPU 201 determines a presence / absence of an abnormal nozzle based on an input from the discharge abnormality detection unit 30, an abnormal nozzle counting unit 211 which counts the number of occurrences of abnormal nozzles, and a number of occurrences of abnormal nozzles. Functions as a tolerance value determination unit 212 that compares the threshold value with a predetermined threshold value.

(Print processing when an abnormal nozzle occurs)
Hereinafter, printing processing when an abnormal nozzle is generated by the inkjet recording apparatus according to the present embodiment will be described.

  As in the inkjet recording apparatus 10 according to the present embodiment, when transparent clear ink is ejected as an additional droplet, it is difficult to detect even if nozzle omission occurs in the recording head 21t. In addition, when a nozzle missing occurs during printing, it is necessary to trace an occurrence location later, so that an image defect such as insufficient fixing ability of an image or uneven gloss may be missed.

  In addition, in the line type inkjet recording apparatus in which one pass printing is the principle, in order to complement the nozzle omission with a normal nozzle, it is necessary to separately provide a complementary recording head. This leads to the complexity of the configuration and the cost increase.

  Therefore, the inkjet recording apparatus according to the present embodiment includes a recording head (recording head 21) provided with a plurality of nozzles (nozzles 22) for discharging droplets, and forms an image with a predetermined resolution based on image data. It is an inkjet recording apparatus (inkjet recording apparatus 10), and it is based on the detection result of a discharge abnormality detection unit (discharge abnormality detection unit 30) that detects whether a droplet is discharged normally from a nozzle and a discharge abnormality detection unit. And a control unit that counts the number of abnormal nozzles and discharges droplets from the nozzles so that the resolution becomes lower than a predetermined resolution when the counted number of abnormal nozzles exceeds a threshold (discharge abnormality of the control unit 200 A determination unit 210, an abnormal nozzle count unit 211, an allowance determination unit 212, a print control unit 207, and the like). In addition, the code | symbol in embodiment and the application example are shown in a parenthesis.

[Printing process (1)]
FIG. 7 is a flowchart showing an example of the printing process performed by the inkjet recording apparatus 10 according to the present embodiment. In the present embodiment, a process of determining the ejection abnormality of the nozzles of the recording head 21t that ejects the additional droplet will be described. For this reason, the ejection abnormality detection unit 30 only needs to detect at least the ejection abnormality of the additional droplet from each nozzle 22 of the recording head 21t.

  First, during the printing operation, the discharge abnormality detection unit 30 (FIG. 5) detects the discharge abnormality of the nozzle (S101), and based on the detection result, the discharge abnormality determination unit 210 detects the presence or absence of the abnormal nozzle. (S102).

  If there is no abnormal nozzle (S102: NO), printing is continued until printing is completed (S108). On the other hand, when there is an abnormal nozzle (S102: YES), the ejection abnormality judgment unit 210 ejects additional droplets to the area where an image is formed by the abnormal nozzles by the recording heads 21k to 21y (hereinafter, image forming area). It is judged whether it is what it is (S103).

  Although the process of S103 is not an essential process, if the abnormal nozzle is outside the printing area (including the width of the recording medium), it can be tolerated during printing, and the complementation is performed. It is something that you do not want. Since the determination of the image formation area can be made based on the image data by the control unit 200, the control is simple, and the discharge amount of the additional droplet can be reduced.

  If the abnormal nozzle does not eject the image forming area (S103: NO), printing continues until the printing is completed (S108). On the other hand, when the malfunctioning nozzle is to discharge to the image forming area (S103: YES), the process proceeds to the complementing process (S104) in the nozzle (hereinafter, the adjacent nozzle) adjacent to the malfunctioning nozzle.

  First, the occurrence position of the malfunctioning nozzle is stored in the storage unit (for example, the RAM 203), and the malfunctioning nozzle counting unit 211 counts the number of malfunctioning nozzles occurring (S105).

  Next, the tolerance value determination unit 212 determines whether the counted number of occurrences of abnormal nozzles exceeds the set threshold (the first tolerance and the first threshold) (S106).

  If the number of occurrences of the abnormal nozzles does not exceed the first allowable value (S106: NO), it is permitted to drop out during printing, so that the complementing is not performed. On the other hand, when the number of abnormal nozzles exceeds the first allowable value (S106: YES), the control unit 200 controls the print control unit 207 to lower the resolution of the adjacent nozzles, and the abnormal nozzles are larger in droplet size. Fills the area to be discharged originally (S107). As a result, it is possible to secure a discharge amount which must be discharged per unit area.

  Of course, regardless of the number of abnormal nozzles, if an abnormal nozzle occurs, the resolution may be reduced by the adjacent nozzles to compensate.

  In addition, it is also preferable to change the waveform (flushing discharge waveform) or change the flushing amount in the flushing process in which droplets not contributing to image formation are ejected at predetermined intervals during the printing operation after the resolution reduction process (S107). . As a result, the flushing amount can be increased to recover the nozzles during the printing operation.

  Detection of discharge abnormality of the nozzle by the discharge abnormality detection unit 30 is performed until printing is completed (S108: YES) (S108: NO).

  After completion of printing (S108: YES), if an abnormal nozzle is generated during printing (S109: YES), a notification prompting execution of maintenance is output to the operation panel 213 (S110), and the printing process ends. Note that the maintenance execution notification may be displayed during the printing operation.

[Printing process (2)]
FIG. 8 is a flowchart showing another example of the printing process performed by the inkjet recording apparatus 10 according to the present embodiment. In addition, since the process of S201-S207 is the same as that of S101-S107 shown in FIG. 7, description is abbreviate | omitted.

  At this time, the tolerance value determination unit 212 determines that the threshold number of abnormal nozzles is larger than the first tolerance value (the second tolerance value and the second threshold value). It is judged whether it exceeded (S208). The second allowable value is a threshold value for determining the number of occurrences of abnormal nozzles that are difficult to cope with by the reduction processing (S207).

  If the number of occurrences of the abnormal nozzle does not exceed the second allowable value (S208: NO), the process is the same as in the example of FIG. 7 until the printing is completed. On the other hand, if the second allowable value is exceeded (S208: YES), the response by the complementation is not sufficient, and image deterioration may occur.

  Therefore, when the second allowable number is exceeded, the print position (page, position in the page) corresponding to the occurrence position of the abnormal nozzle is stored in the storage unit (S209).

  After completion of printing (S210: YES), if the abnormal nozzle has occurred during printing exceeding the second allowable value (S211: YES), the occurrence point of the abnormal nozzle stored in the storage unit, that is, the fixability defect Are displayed on the operation panel 213 (S212).

  Further, a notification to urge execution of maintenance is output to the operation panel 213 (S213), and the printing process ends. Note that the maintenance execution notification preferably exceeds the first allowable value and is less than the second allowable value (S208: NO). The display of the abnormal portion (S212) and the maintenance execution notification (S213) may be displayed during the printing operation.

  Next, an example of notification to the operation panel 213 is shown. FIG. 9 shows an example of notifying the user of the occurrence position of the abnormal nozzle displayed on the operation panel 213. It shows how many abnormal nozzles are generated at which position of each recording head 21. Further, FIG. 9 also shows the number of occurrences of abnormal nozzles at successive positions. Also, the corresponding print position may be displayed together. As a result, the user can recognize a portion where image deterioration may occur, and can confirm the formed image and determine whether or not maintenance needs to be performed. Note that the notification example illustrated in FIG. 9 is an example, and the present invention is not limited to this. The display timing is displayed, for example, in the process of S212 of FIG. Also, when the first allowable value is exceeded and the second allowable value is not exceeded, or in the printing process of FIG. 7 described above, the occurrence position and the number of occurrences of the abnormal nozzle may be notified.

  According to the inkjet recording apparatus 10 according to the present embodiment described above, the occurrence of the abnormal nozzle can be detected during the printing operation, and the influence on the image of the abnormal nozzle can be reduced. For example, additional droplets for securing fixability can be secured if a desired amount can be applied per unit area, so even if an acceptable number of nozzles are missed during printing operation By reducing the resolution of the ejection from the adjacent nozzle group of the nozzles and by enabling to cover with a larger droplet, the influence of the abnormal nozzle on the image can be reduced.

  Further, since the printing operation is not interrupted, high productivity can be maintained without reducing the productivity. Further, there is no need to separately provide a complementary recording head, which can be realized with a simple system configuration, and the cost can be suppressed. It is also possible to reduce the amount of waste paper and ink consumption.

  Further, in consideration of the response to the occurrence of an abnormal nozzle, it is particularly preferable to apply to an inkjet recording apparatus that ejects additional droplets such as clear ink. Moreover, it is preferable to apply to the line type inkjet recording device in which it is difficult to interrupt the printing operation.

  Although the application to the recording head which discharges the transparent additional droplet was described as an example in the above-mentioned embodiment, the ink droplet to apply is not restricted to this, and the recording head which discharges the droplet of other colors It may apply to In addition, although the one-pass printing line type inkjet recording apparatus has been described, the printing method is not limited to this.

  Further, each control of the printing process described above may be realized, for example, by causing the inkjet recording apparatus 10 to execute each control according to a control program stored in the storage unit (for example, the ROM 202). .

  The above-described embodiment is an example of the preferred embodiment of the present invention, but is not limited to this, and various modifications can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 10 inkjet recording apparatus 11 edge controller 12 heat roller 20 recording head unit 21 (21k, 21c, 21m, 21y, 21t) recording head 22 nozzle 23 nozzle row 24 small head 30 discharge abnormality detection unit 31 light emitting unit 32 light receiving unit 40 paper feeding Device 50 Paper discharge device 100 Printing system 101 Flow path plate 102 Diaphragm 103 Nozzle plate 105 Nozzle communication path 106 Liquid chamber 108 Common liquid chamber 109 Ink supply port 121 Piezoelectric element 122 Base substrate 123 Strut portion 126 FPC cable 130 Frame member 131 Penetration Part 132 Ink supply hole 151 Piezoelectric material 152 Internal electrode 153 Individual electrode 154 Common electrode 200 Control part 201 CPU
202 ROM
203 RAM
204 NVRAM
205 ASIC
206 Host I / F
207 print control unit 208 motor drive unit 209 I / O
210 ejection abnormality determination unit 211 abnormality nozzle count unit 212 tolerance value determination unit 213 operation panel P recording medium

JP, 2004-276274, A

Claims (9)

A recording head provided with a plurality of nozzles for discharging droplets;
An inkjet recording apparatus that forms an image at a predetermined resolution based on image data, comprising:
A discharge abnormality detection unit that detects whether droplets are normally discharged from the nozzle;
Based on the detection result of the discharge abnormality detection unit, the number of abnormal nozzles is counted, and when the counted number of abnormal nozzles exceeds a threshold, the resolution is lower than the predetermined resolution from the nozzles And a controller for discharging droplets .
The recording head includes a recording head which discharges a droplet containing a color material used for image formation, and a recording head which discharges an additional droplet after the image formation by the recording head.
3. The inkjet recording apparatus according to claim 1, wherein the control unit executes control to make the resolution of the recording head that discharges the additional droplet low .   The inkjet recording apparatus according to claim 1, wherein the control unit increases a droplet size discharged from a nozzle adjacent to the abnormal nozzle. The control unit determines whether the abnormal nozzle is at a position corresponding to an area on which an image is formed by the recording head that discharges the droplet including the color material, with respect to the recording head that discharges the additional droplet. Judge
Not correspond to an ink jet recording apparatus according to claim 1 or 2, characterized in that it does not perform a control for said low resolution. The threshold is a first threshold, and a second threshold is set as a value larger than the first threshold,
The controller according to any one of claims 1 to 3 , wherein the control unit does not execute the control for setting the low resolution when the counted number of the abnormal nozzles exceeds the second threshold. The inkjet recording device as described. 5. The inkjet recording apparatus according to claim 4 , wherein the control unit causes the operation unit to display the occurrence location and the occurrence number of the abnormal nozzle when the second threshold is exceeded. The control unit is configured to change at least one of a flushing amount and a flushing discharge waveform in a flushing process for discharging droplets not contributing to image formation at predetermined intervals during image formation, for the abnormal nozzle. The inkjet recording device according to any one of 1 to 5 . The ink jet recording apparatus according to any one of claims 1 to 6 , wherein the recording head is a line head having an image forming width equal to the width of a recording medium. The recording head includes a recording head provided with a plurality of nozzles for ejecting the droplets, and the recording head ejects additional droplets after the image formation by the recording head, and the recording head for ejecting the droplets containing the color material used for image formation. Recording head, and
A control method of an ink jet recording apparatus which forms an image at a predetermined resolution based on image data,
A discharge abnormality detection process for detecting whether droplets are normally discharged from the nozzle;
The number of abnormal nozzles is counted based on the detection result in the ejection abnormality detection process, and the predetermined number of recording heads for ejecting the additional droplets when the counted number of abnormal nozzles exceeds a threshold. A resolution reduction process in which droplets are discharged from the nozzle so that the resolution is lower than the resolution;
And a control method of an ink jet recording apparatus. The recording head includes a recording head provided with a plurality of nozzles for ejecting the droplets, and the recording head ejects additional droplets after the image formation by the recording head, and the recording head for ejecting the droplets containing the color material used for image formation. Recording head, and
A control program of an ink jet recording apparatus for forming an image at a predetermined resolution based on image data, the control program comprising:
A discharge abnormality detection process for detecting whether droplets are normally discharged from the nozzle;
The number of abnormal nozzles is counted based on the detection result in the ejection abnormality detection process, and the predetermined number of recording heads for ejecting the additional droplets when the counted number of abnormal nozzles exceeds a threshold. A control program of an ink jet recording apparatus, which causes the ink jet recording apparatus to execute a resolution reducing process of discharging droplets from the nozzles so as to have a resolution lower than the resolution.