JP2006069226A - Checkup of nozzle after nozzle cleaning - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To alleviate the deterioration of an image quality caused by nozzle clogging even in possible cases where the clogging in nozzles is not resolved by cleaning. <P>SOLUTION: In cases where a cleaning mechanism executes cleaning according to predetermined causes, except for cases where a non-function nozzle failing to eject ink droplets is detected by a checkup part, a nozzle check is automatically performed by the checking part after the cleaning process. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a technique for printing an image by ejecting ink droplets from a plurality of nozzles and recording dots on the surface of a print medium, and in particular, nozzle inspection for inspecting whether or not ink droplets are ejected from each nozzle. Relates to printing technology using

  An ink jet printer prints an image by ejecting ink droplets from a plurality of nozzles. A print head of an inkjet printer is provided with a large number of nozzles. However, there are cases where some nozzles are clogged and ink droplets cannot be ejected due to an increase in the viscosity of ink or mixing of bubbles. When the nozzles are clogged, dots are lost in the image, causing deterioration in image quality. In the present specification, the nozzle inspection is also referred to as “dot missing inspection”.

  A normal ink jet printer is provided with a cleaning mechanism in order to eliminate clogging of nozzles. The user can perform cleaning at any time by operating a button of the printer.

  However, even if the nozzle is cleaned, clogging is not always eliminated. In addition, in rare cases, due to sufficient measures taken due to the structure of the cleaning mechanism and the contrivance of the cleaning sequence, in some cases, nozzles that were not clogged before cleaning cause clogging due to cleaning. Sometimes. As described above, since clogging of the nozzles may not be eliminated by cleaning, there is a problem that a desired image quality may not be obtained even if printing is performed after cleaning.

  The present invention has been made to solve the above-described problems in the prior art, and even when there is a possibility that nozzle clogging may not be eliminated by cleaning, image quality degradation caused by the clogging can be alleviated. The purpose is to provide technology.

  In order to solve at least a part of the above-described problem, in the present invention, when the cleaning mechanism performs cleaning according to a predetermined trigger other than that the non-operating nozzle that cannot eject ink droplets is detected by the inspection unit, After the cleaning, the nozzle is automatically inspected by the inspection unit. In this way, when there is a possibility that nozzle clogging may not be eliminated by cleaning, it is possible to know whether or not each nozzle is clogged. Therefore, if an appropriate printing operation is selected according to the presence or absence of clogging after cleaning, image quality deterioration can be alleviated.

  In addition, when a non-operating nozzle is detected by inspection of the nozzle after cleaning, and a use nozzle row that can be used for printing can be configured by only the operation nozzle, the use nozzle that is configured by only the operation nozzle when performing subsequent printing Printing is preferably performed using the columns. In this way, even if there are non-operating nozzles, it is possible to perform normal printing with only the operating nozzles.

  In addition, when non-operating nozzles are detected by inspection of the nozzles after cleaning and the used nozzle row used for printing cannot be configured by only the operating nozzles, the non-operating included in the used nozzle row at the time of subsequent printing It is preferable to execute printing in accordance with a printing operation including a complementary operation in which dots on the main scanning line to be recorded by the nozzles are recorded using other operation nozzles. In this way, since the dots to be recorded by the non-operating nozzles can be recorded by other operating nozzles, it is possible to prevent image quality deterioration.

  The cleaning may include an operation of sucking ink from a plurality of nozzles to the outside. In such a cleaning, sufficient measures have been taken due to the structure of the cleaning mechanism and the contrivance of the cleaning sequence, but the possibility that the nozzles that were not clogged before cleaning are clogged after cleaning is compared. It seems to be high. Therefore, if the nozzle is inspected after such cleaning, the above-described effect is particularly great. Further, if the nozzle inspection is executed after cleaning, a complicated cleaning mechanism can be simplified.

  The present invention can be realized in various modes such as a printing apparatus control method, a printing method, a printing apparatus, and a recording medium on which a computer program for realizing the functions of these methods and apparatuses is recorded. .

A. Device configuration:
Next, embodiments of the present invention will be described based on examples. FIG. 1 is a schematic perspective view showing a main configuration of a color inkjet printer 20 as an embodiment of the present invention. The printer 20 includes a paper stacker 22, a paper feed roller 24 driven by a step motor (not shown), a platen plate 26, a carriage 28, a step motor 30, and a traction belt 32 driven by the step motor 30. And a guide rail 34 for the carriage 28. A print head 36 having a large number of nozzles is mounted on the carriage 28.

  A first dot dropout inspection unit 40 and a second dot dropout inspection unit 42 are provided at the standby position of the carriage 28 at the right end of FIG. The first missing dot inspection unit 40 includes a light emitting element 40a and a light receiving element 40b, and inspects missing dots by examining the flight state of ink droplets using these elements 40a and 40b. The second dot dropout inspection unit 42 inspects for dot dropout by checking whether or not the vibration plate provided on the surface vibrates with ink droplets. Detailed contents of the inspection by each dot dropout inspection unit will be described later.

  The printing paper P is taken up by the paper feed roller 24 from the paper stacker 22 and fed on the surface of the platen plate 26 in the sub-scanning direction. The carriage 28 is pulled by a pulling belt 32 driven by a step motor 30 and moves in the main scanning direction along the guide rail 34. The main scanning direction is perpendicular to the sub-scanning direction.

  FIG. 2 is a block diagram showing an electrical configuration of the printer 20. The printer 20 includes a reception buffer memory 50 that receives a signal supplied from the host computer 100, an image buffer 52 that stores print data, a system controller 54 that controls the operation of the entire printer 20, and a main memory 56. ing. The system controller 54 includes a main scanning drive driver 61 that drives the carriage motor 30, a sub-scanning drive driver 62 that drives the paper feed motor 31, and an inspection unit driver 63 that drives the two dot dropout inspection units 40 and 42, respectively. 64 and a head drive driver 66 for driving the print head 36 are connected. The paper feed motor 31 is also used as a motor for operating a cleaning mechanism 200 (described later).

  A printer driver (not shown) of the host computer 100 determines various parameter values that define the printing operation based on the printing mode (high-speed printing mode, high-quality printing mode, etc.) designated by the user. The printer driver further generates print data for printing in the print mode based on these parameter values, and transfers the print data to the printer 20. The transferred print data is temporarily stored in the reception buffer memory 50. In the printer 20, the system controller 54 reads necessary information from the print data from the reception buffer memory 50, and based on this, sends a control signal to each driver.

  The image buffer 52 stores print data of a plurality of color components obtained by separating the print data received by the reception buffer memory 50 for each color component. The head drive driver 66 reads the print data of each color component from the image buffer 52 in accordance with a control signal from the system controller 54 and drives the nozzle array of each color provided in the print head 36 according to this.

  The printer 20 can execute printing in the overlap printing mode. “Overlap printing mode” means that only one intermittent pixel position on each raster line is recorded in one main scan, and all pixel positions on each raster line are recorded in a plurality of main scans. This is the mode. For example, when a single raster line is recorded by two main scans, only even pixel positions are recorded in the first main scan on the raster line, and only odd pixel positions are recorded in the second main scan. set to target. In this way, by performing the main scanning twice, all pixel positions on each raster line can be recorded. In this specification, “pixel position” and “dot position” are synonymous. “Main scanning line” and “raster line” are also synonymous.

  In the overlap printing mode, the number of main scans executed to record all pixel positions on one raster line is hereinafter referred to as “scan repetition number”. As the number of scan repetitions, an integer value such as 2 or 4 is often used, but in general, an arbitrary real number of 1 or more can be selected. When the number of scan repetitions is greater than 1 and less than 2, it is called “partial overlap printing mode”. In the partial overlap printing mode, there are raster lines in which all pixel positions are to be recorded in one main scan, and raster lines in which all pixel positions are to be recorded in two main scans. Note that the conditions for establishing the overlap printing mode are described in detail in Japanese Patent Laid-Open No. 10-278247 disclosed by the applicant of the present invention, and a description thereof is omitted here.

  In the overlap printing mode, each raster line is not recorded by one nozzle but is recorded by using a plurality of nozzles. Therefore, even when there are variations in nozzle characteristics (pitch, ejection characteristics, etc.), it is possible to prevent the influence of specific nozzle characteristics from affecting one entire raster line, and as a result, image quality can be improved. There is an advantage that you can.

  The overlap printing function, the inspection execution function, the complement target registration function, the complement execution function, the cleaning execution function, and the like are realized by the system controller 54. A computer program for causing the system controller 54 to realize these functions is stored in the main memory 56.

B. Configuration and principle of the missing dot inspection unit:
FIG. 3 is an explanatory diagram showing the configuration of the first dot dropout inspection unit 40 and the principle of the inspection method (flight drop inspection method). FIG. 3 is a view of the print head 36 viewed from the lower surface side, in which the nozzle array for six colors of the print head 36 and the light emitting element 40a and the light receiving element 40b constituting the first dot dropout inspection unit 40 are drawn. ing.

The lower surface of the print head 36, and the black ink nozzle group K _D for ejecting black ink, a dark cyan ink nozzle group C _D for ejecting dark cyan ink, for ejecting light cyan ink light cyan yellow ink for ejecting the ink nozzle group C _L, and dark magenta ink nozzle group M _D for ejecting dark magenta ink, light magenta ink nozzle group M _L for ejecting light magenta ink, a yellow ink a nozzle group Y _D is formed.

Note that the capital letter of the first alphabet in the code indicating each nozzle group means the ink color, the subscript “ _D ” indicates that the ink is relatively high, and the subscript “ _L ” This means that the ink has a relatively low density. The subscript “ _D ” of the yellow ink nozzle group Y _D indicates that the yellow ink discharged from the nozzle group becomes a gray color when it is mixed with dark cyan ink and dark magenta ink in approximately equal amounts. I mean. The subscript of the black ink nozzle group K _{D "D",} the black ink ejected from those without the gray, which means that a concentration of 100% black.

  The plurality of nozzles of each nozzle group are aligned along the sub-scanning direction SS. At the time of printing, ink droplets are ejected from each nozzle while the print head 36 moves in the main scanning direction MS together with the carriage 28 (FIG. 1).

The light emitting element 40a is a laser that emits a light beam L having an outer diameter of about 1 mm or less. The laser light L is emitted in parallel with the sub-scanning direction SS and is received by the light receiving element 40b. In the dot missing inspection, first, as shown in FIG. 3, the print head 36 is positioned so that the nozzle group for one color (for example, dark yellow Y _D ) is located above the optical path of the laser light L. . In this state, one by one nozzle dark yellow Y _D with head driver 66 (FIG. 2), and drives one by predetermined driving period, successively to eject ink droplets from the nozzles. Since the ejected ink droplet interrupts the optical path of the laser beam L on the way, the light reception by the light receiving element 40b is temporarily interrupted. Therefore, if the ink droplets are normally ejected from a certain nozzle, the laser light L is temporarily blocked by the light receiving element 40b, so that it can be determined that the nozzle is not clogged. Further, when the laser light L is not shielded at all within the drive period of a certain nozzle, it can be determined that the nozzle is clogged. Note that it may be impossible to reliably detect whether or not the laser light L has been blocked with one drop of ink, so it is preferable to eject several drops for each nozzle.

When clogging inspection is completed for all the nozzles for one color, the print head 36 is moved slightly in the main scanning direction, and inspection of the nozzle of the next color (light magenta M _{L in} the example of FIG. 3) is executed. .

  This flying droplet inspection method has an advantage that the inspection is completed in a relatively short time because each nozzle is inspected for clogging (ie, dot missing) by detecting ink droplets in flight.

  FIG. 4 is an explanatory diagram showing another configuration of the first missing dot inspection unit 40. In FIG. 4, the directions of the light emitting element 40a and the light receiving element 40b are adjusted so that the traveling direction of the laser light L is slightly inclined from the sub-scanning direction SS. The traveling direction of the laser beam L is that when the ink droplet ejected from one nozzle is detected by the laser beam L, the laser beam L is shielded by the ink droplet ejected from the other nozzle. It is set so that there is no. In other words, the optical path of the laser light L is set so as not to interfere with the ink droplet paths from the plurality of nozzles.

  In this way, if the laser light L is emitted in an oblique direction inclined from the sub-scanning direction SS, the nozzles are sequentially moved one by one while moving the print head 36 slowly in the main scanning direction. By driving and ejecting ink droplets, it is possible to inspect clogging of each nozzle. This also has an advantage that clogging of the nozzles can be inspected even when ink droplets ejected from some nozzles are slightly deviated from the specified positions and directions.

  FIG. 5 is an explanatory diagram showing the configuration of the second dot dropout inspection unit 42 and the principle of the inspection method (diaphragm inspection method). FIG. 5 is a cross-sectional view of the vicinity of one nozzle n of the print head 36, and a diaphragm 42 a and a microphone 42 b constituting the second dot dropout inspection unit 42 are also drawn.

  The piezo element PE provided in each nozzle n is installed at a position in contact with the ink passage 80 that guides ink to the nozzle n. When a voltage is applied to the piezo element P, the piezo element PE expands and deforms one side wall of the ink passage 80. As a result, the volume of the ink passage 80 contracts according to the expansion of the piezo element PE, and the ink droplet Ip is ejected from the tip of the nozzle n at high speed.

  When the ink droplet Ip ejected from the nozzle n reaches the vibration plate 42a, the vibration plate 42a vibrates. The microphone 42b converts the vibration of the diaphragm 42a into an electric signal. Therefore, by detecting the output signal (vibration sound signal) from the microphone 42b, it is possible to know whether or not the ink droplet Ip has reached the vibration plate 42a (that is, whether or not the nozzle is clogged).

  Note that it is preferable that such a set of diaphragms 42a and microphones 42b be arranged along the sub-scanning direction by the same number as the number of nozzles for one color. In this way, it is possible to simultaneously check for clogging for all nozzles for one color. However, if the ink droplets Ip are simultaneously ejected from the adjacent nozzles, the adjacent diaphragms 42a may interfere with each other and may be erroneously detected. In order to prevent such erroneous detection, it is preferable to set every several nozzles to be inspected at the same time.

  In FIG. 1, two dot dropout inspection units 40 and 42 are shown. However, one printer need only have one dot dropout inspection unit.

C. Configuration and operation of the cleaning mechanism:
FIG. 6 is a conceptual diagram showing the configuration of the cleaning mechanism 200. The cleaning mechanism 200 includes a head cap 210, a hose 220, and a pump roller 230. The cleaning mechanism 200 is provided at a predetermined cleaning position (ink suction position) in the vicinity of the first inspection unit 40 in FIG. 1, but is not illustrated in FIG. 1.

  A rubber frame 214 is provided on the upper surface of the box 212 of the head cap 210. When the print head 36 moves to a predetermined cleaning position in the main scanning direction during cleaning, the head cap 210 rises and the rubber frame 214 comes into close contact with the lower surface of the print head 36. As a result, a closed space is formed by the lower surface of the print head 36 and the head cap 210.

  The pump roller 230 has two small rollers 232 and 234 in the vicinity of the peripheral edge thereof. A hose 220 is wound around these two small rollers 232 and 234. When the pump roller 230 is driven in the direction of arrow A by being driven by the paper feed motor 31 (FIG. 2), the air in the hose 220 is pushed by the small rollers 232 and 234, thereby exhausting the closed space in the head cap 210. The As a result, ink is sucked from each nozzle of the print head 36 and discharged to a waste ink discharge portion (not shown) via the hose 220. When ink present at the nozzle tip is discharged, new ink is supplied to the nozzle from the ink cartridge side.

  When the nozzles are cleaned by sucking ink from the nozzles in this way, sufficient countermeasures have been taken due to the structure of the cleaning mechanism and the contrivance of the cleaning sequence. It may cause clogging. This is considered to be caused by various phenomena as described below. The first phenomenon is a phenomenon in which an air pressure change occurs when the head cap 210 is separated from the print head 36 after ink is sucked, and as a result, bubbles enter the nozzles from the head cap 210 side. . The second phenomenon is a phenomenon in which bubbles that existed in the ink passage 80 (FIG. 5) of the print head 36 before cleaning move to the vicinity of the nozzle tip due to ink suction. When such a phenomenon occurs, a nozzle that was not clogged before cleaning may be clogged by cleaning.

Incidentally, nozzle cleaning is performed in various cases as described below.
(1) Manual cleaning by user operation.
(2) Automatic cleaning after long-term non-use of the printer.
(3) Automatic cleaning upon initial ink filling after ink cartridge replacement.

  The cleaning (2) is a cleaning that is automatically executed by the printer when the ink is not ejected for a certain period. The cleaning (3) is cleaning performed to guide ink from the cartridge to each nozzle when the ink cartridge of the printer is replaced.

  After these cleanings, if the above phenomenon occurs, the nozzles may be clogged. Therefore, in this embodiment, after the cleaning of (1) to (3) above, the printer automatically executes the nozzle clogging inspection to check the operation state of each nozzle.

  As a nozzle cleaning method, a method in which ink is not sucked from the nozzle is also conceivable. However, with a cleaning method that does not suck ink from the nozzles, it is considered that the possibility of nozzle clogging due to cleaning is low. Therefore, if the nozzle is inspected especially after cleaning including ink suction from the nozzle, the effect of reducing image quality degradation due to missing dots is great.

  In this specification, “cleaning” in a narrow sense means an operation of sucking ink from a nozzle to the outside. Further, “cleaning” in a broad sense means various cleanings including a method in which ink is not sucked from the nozzles. The present invention can be applied when cleaning in a broad sense is performed, but as described above, it is most effective when cleaning in a narrow sense is performed.

  In this specification, an event that triggers the start of cleaning is referred to as a “cleaning trigger event”. In the cases (1) to (3), the user's operation, the printer is not used for a long time (ink is not discharged for a long time), and the ink cartridge is replaced, respectively.

  These cleaning incentive events do not necessarily mean that the nozzle is clogged. For example, the cleaning (1) may be performed as a precaution in order for the user to reliably prevent nozzle clogging. As described above, when the cleaning mechanism 200 performs the cleaning in response to the cleaning-inducing event that occurs when the nozzle is not necessarily clogged, the dot missing inspection unit after the cleaning is performed. The feature is that the nozzle inspection is automatically executed. By doing so, it is possible to know whether or not nozzle clogging has occurred due to the cleaning. Further, when nozzle clogging occurs, it is possible to prevent image quality deterioration by selecting an appropriate printing operation, as will be described later.

D. Example procedure:
FIG. 7 is a flowchart showing the printing processing procedure in the first embodiment. When a cleaning incentive event occurs in step S1, the printer 20 automatically executes the processing from steps S2 to S4. As described above, the cleaning incentive event includes three events: a user operation, a printer not used for a long time (ink is not discharged for a long time), and an ink cartridge replacement.

  In step S2, nozzle cleaning using the cleaning mechanism 200 (FIG. 6) is executed. In step S3, the clogging inspection of all the nozzles for six colors is executed using the dot missing inspection unit 40. In the following description, the first dot dropout inspection unit 40 is used unless otherwise specified, but the second dot dropout inspection unit 42 can be used instead.

  If it is determined in step S4 that there are no non-operating nozzles (that is, clogged nozzles), the processing in step S5 is executed during subsequent printing. In step S5, when a printing command is received from the computer 100, a normal printing operation is selected, and printing is executed in step S7.

  On the other hand, if it is determined in step S4 that there is a non-operating nozzle, the processing in step S6 is executed during subsequent printing. In step S6, when a printing command is received from the computer 100, a printing operation that does not use a non-operating nozzle is selected, and printing is executed in step S7.

  FIG. 8 is a flowchart showing the detailed procedure of step S6. In step S <b> 11, it is determined whether the used nozzle row can be configured with only the operating nozzles. At the time of printing, not all nozzles of each nozzle group are used, and depending on the print mode, a plurality of nozzles may be selected from each nozzle group and used. The “used nozzle row” means a nozzle row that is actually used for the printing operation in the nozzle group of each ink.

  FIG. 9A shows a case where the used nozzle row can be configured with only the operating nozzles, and FIG. 9B shows a case where the used nozzle row cannot be configured with only the operating nozzles. Here, it is assumed that the nozzle group for one color of the print head 36 has 48 nozzles # 1 to # 48. Further, it is assumed that the used nozzle row is composed of 47 nozzles arranged at a constant nozzle pitch k. White circles indicate operating nozzles (no clogging), and black circles indicate non-operating nozzles (no clogging).

  As shown in FIG. 9A, when the use nozzle row can be configured with only the operating nozzles, it is determined that the normal print operation is performed using the use nozzle row (steps S11 and S13 in FIG. 8). ). In the case where a plurality of nozzle arrays for different inks are provided in the print head 36 as in the example of FIG. 3, the operation nozzles at the same position for each ink (for example, nozzle # 2 in FIG. 9A) It is preferable that the used nozzle row can be configured by ~ # 48). In other words, if the used nozzle row cannot be configured with the operating nozzles at the same position for each ink, it may be determined that “the used nozzle row cannot be configured with only the operating nozzles”.

  As shown in FIG. 9B, when the used nozzle row cannot be configured only with the operating nozzle, the printing operation is performed using the used nozzle row including the non-operating nozzle. In this case, a complementary operation is performed in which the pixel position where the non-operating nozzle is in charge of recording is recorded using another operating nozzle. This complementary operation depends on whether the print mode is the overlap print mode or not. Different. Therefore, in step S12 of FIG. 8, it is determined whether or not the print mode is the overlap print mode. If the print mode is not the overlap print mode, a print operation involving complementation by a complementary pass is selected (step S14). On the other hand, if it is the overlap printing mode, the printing operation accompanied by the complement at the time of overlap is selected (step S15). The contents of steps S14 and S15 will be described later.

  As described above, in this embodiment, when the cleaning of the nozzle is performed due to the occurrence of the cleaning-inducing event, the nozzle inspection is automatically performed after the cleaning. As a result, it is possible to reliably detect nozzle clogging that may occur due to cleaning. In addition, when a clogged nozzle is detected by this nozzle inspection, the printing operation is selected so as to prevent the occurrence of missing dots due to the non-operating nozzle during subsequent printing. Therefore, even when nozzle clogging occurs due to cleaning, it is possible to reduce image quality deterioration due to this.

E. Printing operation with a complementary pass:
FIG. 10 is an explanatory diagram showing an example of a complement operation (step S14 in FIG. 8) involving a complement path. In this specification, one main scan during a printing operation is referred to as a “pass”. In the case of bidirectional printing, one forward scan is one pass, and one return scan is one pass. A path added for completion is called a “complement path”.

  In FIG. 10, for the sake of simplicity, it is assumed that the print head 36 has only four nozzles, and the second nozzle is a non-operating nozzle (a nozzle that is clogged). The other nozzles are assumed to be operating nozzles (no clogging nozzles). Further, it is assumed that the nozzle pitch k is 3 dots and the sub-scan feed is performed with a constant feed amount F of 4 dots. FIG. 10A shows a normal printing operation when complementing is not performed. Here, since the second nozzle is clogged, it is impossible to record dots on the raster line indicated by the broken line in pass 1 printing. If the complementing operation is not performed, printing of each pass is executed one after another while the dots are not formed on the raster line.

  FIG. 10B shows a printing operation with complementation by a complementing pass. It is the same as FIG. 10A that the missing dots occur in the printing of pass 1. By the way, in the inspection of step S3 in FIG. 7, since it is detected that the second nozzle is a non-operating nozzle, it is recognized that dot missing occurs on the raster line indicated by the broken line. Therefore, after pass 1, sub-scan feed is first performed with a transient feed amount Fa, and other operation nozzles are positioned on the raster line (indicated by a broken line) in which dot missing has occurred in pass 1. . In the example of FIG. 10B, by setting the transient sub-scan feed amount Fa to 3 dots, the first nozzle is positioned on the raster line where the missing dot has occurred. In this state, one-pass printing for complementation is performed, and a recording operation on a raster line in which dot missing has occurred is executed using the first nozzle. In order to perform such a complementary operation, the print data of pass 1 is held in the image buffer 52 (FIG. 2) even after the print of pass 1 is executed, and dot missing has occurred in the print data. The above complement operation is performed using the print data on the raster line.

  In the complementary pass, only the dot recording on the raster line where the missing dot has occurred may be executed, but the dot recording on the other raster line may be executed simultaneously. That is, in the complementary pass, dot recording may be performed again on at least one raster line including at least a raster line in which dot missing has occurred. However, if only dot recording is performed on raster lines with missing dots, there is an advantage that higher image quality can be achieved because it is not necessary to overprint dots on a normally printed raster line. . There is also an advantage that ink can be saved.

  When the complementary pass is completed, the sub-scan feed is performed with the transient feed amount Fb, and the print head 36 is moved to a position suitable for the next pass of the normal printing operation (ie, pass 2). The feed amount Fb of the sub-scan feed performed after the complementary pass is set so that the sum (Fa + Fb) with the feed amount Fa of the first transient feed becomes equal to the feed amount F in the normal printing operation. The “feed amount F in a normal printing operation” means a regular feed amount when no missing dot has occurred. Note that the feed amount F in the normal printing operation may be set to a different value for each pass. As described above, when two transitional sub-scan feeds before and after the complementary pass are combined, if the same feed amount as that of the normal one sub-scan feed is realized, the normal print operation is performed next. The print head 36 can be correctly positioned at the position of the pass. Therefore, it is possible to easily execute the dot missing complement without changing the entire printing operation. Note that the control of the complementary operation as described above is executed by the system controller 54.

  FIG. 11 is an explanatory diagram illustrating another example of a printing operation involving complementation using a complementing pass. In FIG. 11, it is assumed that the first nozzle is a non-operating nozzle and the other nozzles are operating nozzles. FIG. 11A shows a printing operation when complementing is not performed, and FIG. 11B shows a printing operation when complementing is performed. In this example, the first nozzle, which is a non-operating nozzle, is at the rearmost in the sub-scanning direction (paper feeding direction), so even if a positive value is set as the feed amount Fa of the first transient feed, dot missing It is not possible to position another operation nozzle on the raster line where the occurrence of the error occurs. Therefore, the feed amount Fa of the first transient feed is set to a negative value (−3 dots in the example of FIG. 10B), and dot missing occurs in the second nozzle, which is another operation nozzle. Is positioned on the raster line. The feed amount Fb of the second transient feed after the completion of the complementary pass is the sum (Fa + Fb) of the feed amount Fa of the first transient feed equal to the normal feed amount F, as in FIG. It is set as follows.

  In the case of FIG. 10 described above, the first overfeed amount Fa can also be set to a negative value, as in the case of FIG. However, the sub-scan feed (also referred to as “back feed”) in which the feed amount is negative may include a relatively large feed error due to the backlash of the sub-scan feed mechanism. Since a large feed error deteriorates the image quality, it is preferable to adopt positive values as much as possible for the feed amounts Fa and Fb of the transient feed.

  In this way, when the nozzle array in use includes non-operating nozzles, a complementary pass is added, and dot missing is complemented by using other operating nozzles in this complementary pass. It is possible to print the image.

F. Printing operation with completion when overlapping:
FIG. 12 is an explanatory diagram showing a normal printing operation in the overlap printing mode. Here, the “normal printing operation” means a printing process that does not perform a complementing process. In FIG. 12, for the sake of simplicity, it is assumed that the printing process is performed using eight nozzles of the print head 36. The numbers enclosed in circles in the figure are nozzle numbers. Further, the number surrounded by a double circle indicates that the nozzle is a non-operating nozzle (nozzle causing clogging). In this example, the sixth nozzle is a non-operating nozzle, and the other nozzles are kept operating nozzles (no clogging). The nozzle pitch k in the sub-scanning direction is 3 dots.

  The number of scan repetitions s in this overlap printing mode is 2. As described above, the “scan repetition number” is the number of main scans executed to record all pixel positions on one raster line. That is, in this example, all pixel positions on each raster line are to be recorded by two main scans.

  In the normal printing operation shown in FIG. 12, three passes for recording even-numbered pixel positions and three passes for recording odd-numbered pixel positions are alternately executed. From pass 1 to pass 3, even pixel positions are to be recorded, and from pass 4 to pass 6, odd pixel positions are to be recorded. The raster line recorded by each nozzle in the pass when the even pixel position is the recording target is drawn with a solid line, and the raster line recorded by each nozzle in the pass where the odd pixel position is the recording target Is drawn with a dashed line. A raster line that is a recording target of a non-operating nozzle (that is, a raster line with missing dots) is drawn with a dotted line. Therefore, one raster line without dot missing is expressed by two lines, a solid line and a one-dot chain line.

  The right side of FIG. 12 shows the dot recording state on each raster line. White circles indicate pixel positions where dots are missing, and circles filled with a hatched pattern indicate recordable pixel positions. For example, in raster line L1, the sixth nozzle is responsible for recording even pixel positions in pass 2, and the second nozzle is responsible for recording odd pixel positions in pass 5, but the sixth nozzle Is not operating, the even-numbered pixel position of the raster line L1 is not recorded, and dot missing has occurred. Similarly, in the raster lines L2, L3, L4, etc., dot omission occurs at the pixel position where the sixth nozzle is in charge of recording.

  In FIG. 12, it is assumed that only the eighth nozzle is used in pass 1. Therefore, in pass 1, dot missing due to the sixth nozzle does not occur.

  Between each pass, sub-scan feed is performed with a constant feed amount F of 4 dots. Paper feed is executed from the lower side to the upper side in FIG. 12, but in FIG. 12, for the convenience of illustration, the print head 36 is depicted as if it is moving in the direction opposite to the paper feed direction. The sub-scan feed amount F does not have to be a constant value, and a plurality of different values can be used in combination.

  As will be described later, the specific content of the complementary processing in the overlap printing mode depends on whether the non-operating nozzle is the preceding nozzle or the succeeding nozzle. FIG. 13 is an explanatory diagram showing the classification of the preceding nozzle and the succeeding nozzle. The “preceding nozzle” refers to a nozzle in which another nozzle is positioned during any one of the main scans on the raster line on which the nozzle has performed recording. Further, the “following nozzle” refers to a nozzle on which no other nozzle is positioned during any one of the main scans on the raster line on which the nozzle has performed recording. Specifically, as shown in FIG. 13A, when the scan repetition number s is 2, the 5th to 8th nozzles are the preceding nozzles, and the 1st to 4th nozzles are the following. Line nozzle. As shown in FIG. 13B, when the scan repetition number s is 4, the third to eighth nozzles are the preceding nozzles, and the first and second nozzles are the trailing nozzles. .

  As can be seen from the example of FIG. 13, the preceding nozzle reaches the tip of the printing paper earliest among N nozzles (N is an integer of 2 or more) used in the printing process {N · ( s-1) / s} nozzles. Further, the trailing nozzles are (N / s) nozzles that reach the leading edge of the printing paper the latest. The preceding nozzle and the succeeding nozzle are classified for each ink nozzle row. For example, as shown in FIG. 3, when there are nozzle rows for six colors, the preceding nozzle and the following nozzle are classified for each ink for six colors.

  FIG. 14 is a flowchart showing the procedure of the printing process in the overlap printing mode. First, in step S21, one-pass printing is executed. The printing process for one pass in step S21 includes a missing dot complementing process, as will be described in detail later. When printing for one pass is completed, it is determined in step S22 whether the non-operating nozzle is the preceding nozzle or the succeeding nozzle.

  If the non-operating nozzle is the preceding nozzle, a post-complementation process by the succeeding nozzle is reserved in step S23. That is, in this case, the fact that the complementary operation is not performed immediately and the complementary operation by the succeeding nozzle is performed in any one of the subsequent passes is registered in the main memory 56 (FIG. 2) as complementary information. For example, in the example of FIG. 12, the sixth nozzle is clogged, and a dot dropout occurs at an even pixel position on the raster line L1. Since the sixth nozzle is a preceding nozzle, it is registered as supplementary information in the processing of step S23 after pass 2 that complementation of the even pixel positions of the raster line L1 is necessary. Similarly, in the process of step S23 after pass 3, it is registered as supplementary information that complementation of even pixel positions of the raster line L2 is necessary. The same applies to each path after path 4. In the following, the complement process performed in any pass of the normal printing operation after the detection of missing dots is referred to as “post-completion process”. Also, the raster line that is the target of post-complementation processing is called “post-completion target line” or simply “complement target line”, and the pixel position that is the target of post-complementation processing (that is, the pixel position where the missing dot has occurred) Is called “post-completion target pixel position” or simply “complementation target pixel position”.

  Note that the supplement information for the post-complement processing includes at least information indicating the position of the complement target line and information indicating the complement target pixel position (whether the pixel position is an even pixel position or an odd pixel position). Also, the print data that should have been used for recording the pixel position to be complemented (for example, print data at the even pixel position of the raster line L1) is used for complement processing in the image buffer 52 as print data for post-complementation processing. It is stored in a buffer (not shown) and held until the post-complement processing is executed.

  If the non-operating nozzle is a trailing nozzle, step S24 is executed. The contents of step S24 will be described later. When the processing in step S23 or step S24 is completed, it is determined in step S25 whether or not printing for one page has been completed. If not, the process returns to step S21 to execute printing for one pass.

  FIG. 15 is a flowchart showing the detailed procedure of step S21. In step S31, it is determined whether or not recording on a complement target line registered as supplement information is executed. When recording on the complement target line is not executed, the process proceeds to step S32, and printing for one pass, which is the same as the normal printing operation, is executed. On the other hand, when the recording on the complement target line is executed, the process proceeds to step S33. For example, the raster line L1 reserved as a complement target line in pass 2 in FIG. 12 becomes a print target by the second nozzle in pass 5. Therefore, step S33 is executed during pass 5 printing.

  In step S33, the print data for the complement target pixel position on the complement target line is combined with the print data of the normal overlap printing operation. This “print data composition” is a method of combining print data supplied during normal overlap printing operation with respect to operation nozzles that perform complementation on a complement target line, and print data for complement processing in the order of pixel arrangement. It means the processing to arrange. For example, in pass 5 of FIG. 12, since the second nozzle is responsible for recording odd-numbered pixel positions of the raster line L1, the print data supplied to the second nozzle during a normal overlap printing operation is Only print data relating to odd-numbered pixel positions on the raster line L1. On the other hand, the print data relating to the even-numbered pixel positions on the raster line L1 is held in the image buffer 52 (FIG. 2) as complementary processing print data. Therefore, in step S33, these two types of print data are combined to generate print data relating to all pixel positions on the raster line L1. The print data for the other nozzles is the same as that during normal overlap printing operation. In step S34, one-pass printing is executed while performing dot missing complement processing using the combined print data.

  FIG. 16 is an explanatory diagram illustrating a complementary operation when the preceding nozzle is not operating in the overlap printing mode. The pass 1 to pass 4 are the same as the normal printing operation shown in FIG. In pass 5, recording is executed for all pixel positions on the raster line L1 by the second nozzle. In pass 6, recording is executed for all pixel positions on the raster line L2 by the second nozzle. The same applies to each path after path 7. As can be seen from a comparison between FIG. 12 and FIG. 16, when the preceding nozzle is not operating, it is not necessary to add a special pass for complementation, and the dot of the normal overlap printing operation is used. It is possible to compensate for omissions.

  When the number of scan repetitions s is 2, only odd pixel positions or only even pixel positions on each raster line are to be recorded in one pass, whereas post-complementation processing is performed on the complement target line. All the pixel positions are to be recorded. For this reason, when the post-complement processing is performed, if the print head 36 is moved at the same main scanning speed (carriage speed) as that in the normal printing operation, dots are formed at the correct pixel position due to restrictions on the drive characteristics of the print head 36. Sometimes it is not possible. At this time, when the post-complement processing is performed, printing is executed at a slower main scanning speed than in the normal printing operation.

  When the number of scan repetitions s is 4, only one pixel position in the ratio of one pixel to four pixels on each raster line is to be recorded in one pass, whereas in the post-complementation process, the complement target line The pixel positions in the ratio of 2 pixels to the upper 4 pixels are to be recorded. Also at this time, printing may be performed at a main scanning speed slower than that in the normal printing operation as necessary. The adjustment of the main scanning speed during such a complementing operation is similarly performed in the pre-complementing process described later.

  By the way, when the non-operating nozzle is the succeeding nozzle, step S24 of FIG. 14 is executed as follows. That is, in step S24, after the normal pass, the additional complementary processing is immediately performed using the operating nozzles near the non-operating nozzles, and further, the pixel positions where the non-operating nozzles are scheduled to perform recording in the subsequent passes. Is registered for the pre-complementation process by the preceding nozzle. Here, the “additional complement process” means a complement process that is executed by a pass specially added for complementation, not a normal printing operation pass. Further, the “preliminary complement process” means a complement process that is performed in a normal printing operation pass before dot missing actually occurs.

  FIG. 17 is an explanatory diagram showing a complementary operation when the succeeding nozzle is inactive in the overlap printing mode. In this example, the second nozzle is not operating. In pass 1, it is assumed that only the fourth to eighth nozzles are used. Therefore, in pass 1, dot missing due to the second nozzle does not occur.

  In the process of step S24 after pass 2 in which dot missing occurs, an additional complement process is executed using the first nozzle that is the operating nozzle in the vicinity of the second nozzle. That is, as shown in FIG. 17, after the pass 2, the sub-scan feed is performed with the transient first feed amount FCa (= 3 dots), and on the raster line L1 where the missing dot has occurred in the pass 2, Position the first nozzle, which is a near-operating nozzle. Then, the recording relating to the complement target pixel position (that is, the odd pixel position) on the raster line L1 is executed by the first nozzle. This additional complement process is also referred to as an “intermittent complement process” because only the intermittent complement target pixel positions (even pixel positions on the raster line L1) are to be recorded. A path for performing additional complement processing is referred to as a “complement path”. Furthermore, the raster line that is the target of the additional complement process is called an “additional complement target line” or simply “the complement target line”, and the pixel position that is the target of the additional complement process is “additional complement target pixel position” or simply “ This is called “complementation target pixel position”.

  As the transitional sub-scan feed, “reverse feed” in which the feed amount FCa takes a negative value is possible, but normally, the “forward feed” in which the feed amount FCa is positive is the sub-scan feed amount. The error is small. Therefore, it is preferable to select a nozzle that is present behind the non-operating nozzle (the rear side along the paper feeding direction) as the neighboring operating nozzle that is responsible for the additional complementary operation so as to perform forward feeding.

  When the complementary pass is completed in this way, the sub-scan feed is performed with the second transient feed amount FCb (= 1 dot), and the print head 36 is moved so as to realize the nozzle position of the next pass during the normal printing operation. To do. For example, after the completion of the complementary pass after pass 2, the print head 36 is positioned at the pass 3 position.

  As can be seen from FIG. 17, the two sub-scan feeds with the transient feed amounts FCa and FCb are executed between two passes (for example, pass 2 and pass 3) of the normal printing operation. If there is no missing dot, the feed amount F of the sub-scan feed executed during the normal two passes is 4 dots. Accordingly, the two feed amounts FCa and FCb of the transient sub-scan feed are equal to the feed amount F of the sub-scan feed executed during the normal two passes for the total value (FCa + FCb). Is set to be In this way, the print head 36 can be positioned at a position suitable for the next pass of the normal printing operation even after the additional complement processing. Accordingly, since it is only necessary to insert an additional complement operation during the normal printing operation without changing the entire printing operation, it is possible to easily perform dot missing complement.

  The contents of the pre-complementing process reservation in step S24 of FIG. 14 are as follows. Since the clogged second nozzle is the trailing nozzle, the raster line that the second nozzle will subsequently perform recording is in either pass before the second nozzle performs recording. It should be the recording target by the preceding nozzle. In the example of FIG. 17, the raster line L5 that is scheduled to be recorded by the second nozzle in pass 6 is the recording target by the sixth nozzle in pass 3 before that.

  Therefore, in the process of step S24 immediately after pass 2, the raster line scheduled to be recorded by the second nozzle in each pass after pass 3 is reserved as a complement target line. Specifically, raster lines L2, L3, L4, L5... Are reserved as complementation target lines. In this way, since the raster line L5 is reserved as a complement target line when the process according to the procedure of FIG. 15 is executed in pass 3, the processes of steps S33 and S34 are performed on this raster line L5. Executed. Specifically, the sixth nozzle performs recording for all pixel positions on the raster line L5. In this way, the complement processing that is performed in advance before the occurrence of missing dots is called “preliminary complement processing”. Also, the raster line that is subject to pre-complementation processing is called “pre-complementation target line” or simply “complementation target line”, and the pixel position that is subject to pre-complementation processing is “pre-complementation target pixel position” or simply “complementation target line”. This is called “pixel position”.

  The complement information registered for the pre-complementation process includes at least information indicating the position of the complement target line and information indicating the complement target pixel position. However, there is a possibility that print data (for example, print data at even pixel positions of the raster line L5) used in the pre-complementation processing is not supplied from the host computer 100 to the printer side at the time of execution of pass 3 of the normal printing operation. . At this time, after the print data used in the pre-complementation process is supplied from the host computer 100, the pre-complementation process (that is, the print process of pass 3) in steps S33 and S34 is executed.

  Note that among the complement target lines L1 to L7 shown in FIG. 17, raster lines L2, L3, and L4 have already been recorded by the preceding nozzle in a pass before pass 2 (partially omitted in FIG. 17). Is completed, it cannot be a target of the pre-complementation process performed after the pass 3. For such complement target lines L2, L3, and L4, an additional complement process using the nearby operation nozzle is executed in step S5. Specifically, as shown in FIG. 17, immediately after passes 3, 4, and 5, additional interpolation is performed for raster lines L 2, L 3, and L 4 in which dots are missing in passes 3, 4, and 5, respectively. Processing is being executed.

  On the other hand, additional complement processing is unnecessary for the complement target lines L5, L6, L7. Accordingly, in the pass after pass 6 in which the non-operating nozzle (second nozzle) is positioned on the raster line for which the pre-complementation process has been completed, the additional complement process is not necessary. As described above, in the example of FIG. 17, all the supplementary processing can be performed by simply adding the supplementary pass four times to the normal printing operation. Therefore, the entire printing time may be excessively increased for the supplementary processing. There is an advantage that there is no.

  The control of various supplementary operations as described above is executed by the system controller 54.

  As described above, in the overlap printing mode, when a raster line that is a recording target of a non-operating nozzle is a recording target of another operating nozzle in any pass of the normal overlap printing operation, that operating nozzle Completion processing is executed using. Therefore, there is an advantage that dot missing can be complemented without adding a special complement path.

G. Processing procedure of the second embodiment:
FIG. 18 is a flowchart showing a printing processing procedure in the second embodiment. In this procedure, steps S41 to S43 are added after step S4 of the procedure shown in FIG.

  In the second embodiment, when a non-operating nozzle is detected in the nozzle inspection after cleaning (steps S3 and S4), cleaning and nozzle inspection are performed again (steps S41 and S42). When the operation of the non-operating nozzle is recovered by the second cleaning, a normal printing operation is selected in step S5. On the other hand, if there are non-operating nozzles after the second cleaning, a printing operation that does not use non-operating nozzles is selected in step S6. This increases the possibility that the operation of the non-operating nozzles is recovered, so that there is an advantage that the necessity of performing the complementary processing can be reduced.

  In this second embodiment, step S4 is executed when nozzle clogging is not resolved by two cleanings, but this is the first time that nozzle clogging has not been eliminated by three or more cleanings. Step S4 may be executed. That is, in general, the normal printing operation is selected when the nozzle clogging has been eliminated by cleaning up to a predetermined number of times, and the non-operating nozzle is selected during printing only when the nozzle clogging has not been eliminated by cleaning more than a predetermined number of times. It is only necessary to select a printing operation that is not used.

  The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

(1) In the above embodiment, a part of the configuration realized by hardware may be replaced with software, and conversely, a part of the configuration realized by software may be replaced with hardware. Also good.

(2) The present invention is generally applicable to a printing apparatus that ejects ink droplets, and can be applied to various printing apparatuses other than a color inkjet printer. For example, the present invention can be applied to an ink jet facsimile machine and a copying machine.

(3) There are print media that are easily noticeable and missing dots. For example, dot printing is easily noticeable on printing paper dedicated to inkjet printing, and dot missing is not noticeable on ordinary copy paper. Therefore, when using a print medium in which missing dots are not noticeable, the complementary operation may not be performed until a predetermined number of nozzles are clogged. In this way, it is possible to prevent a decrease in image quality without significantly reducing the printing speed.

(4) The types of images to be printed include those in which dot missing is easily noticeable and those that are not noticeable. For example, a missing dot is easily noticeable in a photographic image, but a missing dot is hardly noticeable in a text image including only characters or a graphic image composed of a graphic such as a graph and characters. A printed image that does not include a photographic image, such as a text image or a graphic image, is referred to as a “non-photographic image” in this specification. When printing such a non-photographic image, the complementary operation may not be performed until a predetermined number of nozzles are clogged. When adjusting the complementing operation according to the type of print image in this way, information indicating the type of print image may be registered in the header of print data sent from the computer to the printer side, for example.

1 is a schematic perspective view showing a main configuration of a color inkjet printer 20 as an embodiment of the present invention. FIG. 2 is a block diagram showing an electrical configuration of the printer 20. Explanatory drawing which shows the structure of the 1st dot drop test | inspection part 40, and the principle of the test | inspection method (flight drop test method). Explanatory drawing which shows the other structure of the 1st dot drop test | inspection part. Explanatory drawing which shows the structure of the 2nd dot drop-out inspection part 42, and the original of the inspection method (diaphragm inspection method). The conceptual diagram of the structure of the cleaning mechanism 200. FIG. The flowchart which shows the process sequence of 1st Example. The flowchart which shows the detailed procedure of step S6. Explanatory drawing which shows the case where a use nozzle row | line can be comprised with an operation nozzle, and the case where it cannot be comprised. Explanatory drawing which shows the printing operation by a complementary pass. Explanatory drawing which shows the printing operation by a complementary pass. Explanatory drawing which shows normal printing operation | movement of overlap printing mode. Explanatory drawing which shows the classification | category of the preceding nozzle and the succeeding nozzle in case the scanning repetition number s is 2 and 4. FIG. 6 is a flowchart illustrating a procedure of printing processing in an overlap printing mode. The flowchart which shows the detailed procedure of step S21. Explanatory drawing which shows complementation operation | movement when a succeeding nozzle is non-operation in overlap printing mode. Explanatory drawing which shows complementary operation | movement when a preceding nozzle is non-operation in overlap printing mode. 10 is a flowchart illustrating a procedure of print processing according to a second embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 20 ... Color inkjet printer 22 ... Paper stacker 24 ... Paper feed roller 26 ... Platen board 28 ... Carriage 30 ... Carriage motor 31 ... Paper feed motor 32 ... Traction belt 34 ... Guide rail 36 ... Print head 40 ... 1st dot drop inspection Unit 40a ... light emitting element 40b ... light receiving element 42 ... second dot dropout inspection unit 42a ... diaphragm 42b ... microphone 50 ... reception buffer memory 52 ... image buffer 54 ... system controller 56 ... main memory 61 ... main scanning drive driver 62 ... Sub-scanning drive driver 63 to 65 ... inspection unit driver 66 ... head drive driver 80 ... ink passage 100 ... host computer 200 ... cleaning mechanism 210 ... head cap 212 ... box body 214 ... rubber frame 220 ... hose 230 ... pump Rollers 232, 234 ... small rollers

Claims (9)

Print head having a plurality of nozzles for ejecting ink droplets, cleaning mechanism for cleaning the plurality of nozzles, and inspection unit for inspecting whether each of the plurality of nozzles can eject ink droplets A method of controlling a printing apparatus comprising:
When the cleaning mechanism performs cleaning according to a predetermined cause other than the non-operating nozzle that cannot eject ink droplets being detected by the inspection unit, the inspection unit automatically inspects the nozzle after the cleaning. A method for controlling a printing apparatus, comprising: A method for controlling a printing apparatus according to claim 1, comprising:
When a non-operating nozzle is detected by inspection of the nozzles after cleaning and a use nozzle row that can be used for printing can be configured only by the operation nozzle, a use nozzle that is configured only by the operation nozzle when performing subsequent printing A method for controlling a printing apparatus, wherein printing is performed using a column. A method for controlling a printing apparatus according to claim 1, comprising:
When non-operating nozzles are detected by inspection of the nozzles after cleaning and the use nozzle row used for printing cannot be configured by only the working nozzles, non-operation included in the use nozzle row at the time of subsequent printing A control method for a printing apparatus, wherein printing is executed according to a printing operation including a complementary operation for recording dots on a main scanning line to be recorded by a nozzle using another operation nozzle. A method for controlling a printing apparatus according to claim 1, comprising:
The method of controlling a printing apparatus, wherein the cleaning includes an operation of sucking ink from the plurality of nozzles to the outside. A printing apparatus that performs printing by discharging ink droplets from a plurality of nozzles,
A print head having the plurality of nozzles;
A cleaning mechanism for cleaning the plurality of nozzles;
Inspection that determines whether each nozzle is an operating nozzle that can eject ink droplets or a non-operating nozzle that cannot eject ink droplets by inspecting whether or not ink droplets are ejected from the plurality of nozzles And
A main scanning drive unit that performs main scanning by driving at least one of the print head and the recording medium;
A head driving unit that drives the nozzle rows during the main scanning to perform dot recording;
A sub-scanning drive unit that performs sub-scanning by driving at least one of the print head and the recording medium every time the main scanning is completed;
A control unit for controlling the respective units,
The controller is
When cleaning by the cleaning mechanism is performed according to a predetermined cause other than that the non-operating nozzle is detected by the inspection unit, the inspection of the nozzle by the inspection unit is automatically performed after the cleaning. Characteristic printing device. The printing apparatus according to claim 5,
When the non-operating nozzle is detected by the inspection of the nozzle after cleaning and the use nozzle row used for printing can be configured only by the operating nozzle, the control unit can perform only the operating nozzle during the subsequent printing. A printing apparatus that performs printing using a configured nozzle array. The printing apparatus according to claim 5,
When the non-operating nozzle is detected by the inspection of the nozzle after the cleaning and the use nozzle row used for printing cannot be configured only by the operation nozzle, the control unit performs the use nozzle row during the subsequent printing. A printing apparatus that performs printing in accordance with a printing operation including a complementary operation of recording dots on the main scanning line to be recorded by the non-operating nozzles included in the image using other operating nozzles. The printing apparatus according to claim 5,
The printing apparatus, wherein the cleaning includes an operation of sucking ink to the outside from the plurality of nozzles. Print head having a plurality of nozzles for ejecting ink droplets, cleaning mechanism for cleaning the plurality of nozzles, and inspection unit for inspecting whether each of the plurality of nozzles can eject ink droplets And a computer-readable recording medium that records a computer program for causing a computer including a printing apparatus to execute printing,
When the cleaning mechanism performs cleaning according to a predetermined cause other than the non-operating nozzle that cannot eject ink droplets being detected by the inspection unit, the inspection unit automatically inspects the nozzle after the cleaning. The computer-readable recording medium which recorded the computer program for making a computer implement | achieve the function to be performed to.

Images