WO2000038927A1

WO2000038927A1 - Printing method and printing apparatus for inspecting dot skip and recorded medium on which program therefor is recorded

Info

Publication number: WO2000038927A1
Application number: PCT/JP1999/007386
Authority: WO
Inventors: Hironori Endo
Original assignee: Seiko Epson Corporation
Priority date: 1998-12-25
Filing date: 1999-12-27
Publication date: 2000-07-06

Abstract

Whether a nozzle under inspection is an operating nozzle that can eject an ink droplet or a non-operating nozzle that cannot eject any ink droplet is judged by judging whether or not an ink droplet is ejected from the nozzle under inspection in the course of a one-page printing. If the nozzle is judged to be a non-operating nozzle, a first supplement operation for recording the dot that the non-operating nozzle is to record by means of another operating nozzle is carried out. The nozzle inspection is performed every horizontal scanning during normal printing of when there is no non-operaing nozzle. If any non-operating nozzle is detected by the inspection, a cleaning at least of the non-operating nozzle is performed. Further if the operation of the non-operating nozzle is not restored even after a predetermined number of cleanings, the first supplement operation may be performed.

Description

Specification

TECHNICAL FIELD The present invention relates to a printing method and a printing apparatus for performing dot missing inspection, and a recording medium on which a program for the same is recorded.

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, inspects whether ink droplets are ejected from the nozzles. The present invention relates to a printing technique using dot dropout inspection. Background art

An ink jet printer prints an image by discharging ink droplets from a plurality of nozzles. The print head of an inkjet printer has many nozzles.However, some nozzles may be clogged and ink droplets may not be ejected due to increased ink viscosity or air bubbles. . If the nozzle is clogged, a dot may be missing in the image, which may degrade the image quality.

In the past, nozzle clogging was inspected by printing a special test pattern on printing paper before starting one print job, and visually checking the test pattern by the user. . In this specification, “one print job” means the entire printing operation executed in response to one designation by a user.

In the past, since inspection was performed only before the start of a print job, there was a problem that a desired image quality could not be obtained if a dropout occurred during the printing operation. SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems in the conventional technology, and provides a technology capable of alleviating the deterioration of image quality even when a dot dropout occurs during a printing operation. With the goal. Disclosure of the invention

In order to solve at least part of the above problems, the present invention provides a printing operation for one page. During the operation, by inspecting the presence or absence of the ejection of ink droplets from the nozzles to be inspected, the nozzles to be inspected are checked for the operation nozzles that can eject ink drops and the non-operation nozzles that cannot eject ink drops Decide which one. Then, when the non-operation nozzle is detected by the inspection, a first complementary operation of recording a dot to be recorded by the non-operation nozzle using another operation nozzle is executed. In this way, when a non-operation nozzle is detected, dots are complemented by using another operation nozzle, so that deterioration of image quality due to missing dots occurring during the printing operation can be reduced.

In addition, it is preferable that the nozzle inspection is performed for each main scan in a normal printing operation when there is no non-operation nozzle. In this way, even when a non-operation nozzle is generated, it can be detected in a short time.

When the non-operating nozzle is detected by the inspection, at least cleaning of the non-operating nozzle is performed, and when the operation of the non-operating nozzle is not recovered by the predetermined number of cleanings, the first complementary operation is performed. May be executed.

Further, in a case where the non-operation nozzle is recovered by the cleaning within a predetermined number of times, a second complementary operation of recording a dot that should have been recorded by the non-operation nozzle using the recovered operation nozzle. May be executed. In this way, a dot that has not been recorded can be recorded by the nozzle that was supposed to be in charge of recording the dot, so that the dot can be easily complemented.

It is preferable that the complementary operation is an operation of recording only the dots on the main scanning line to be recorded by the non-operation nozzle using the other operation nozzle or the recovered nozzle. In this way, it is possible to prevent the image quality from deteriorating due to the overprinting of dots on another main scanning line that is normally printed during the supplementary operation.

In the first complementary operation, i) before the first complementary operation, Performing the sub-scan feed with the feed amount of (i), the operating nozzle is positioned on a main scanning line including a dot to be recorded by the non-operating nozzle, and ii) a transient is performed after the first complementary operation. Preferably, the plurality of nozzles are positioned at the nozzle positions in the next main scan of the normal printing operation by performing the sub-scan feed with a typical second feed amount. In this way, it is possible to easily execute the supplementary operation for eliminating missing dots without changing the normal printing operation.

According to another configuration of the present invention, during the printing operation for one page, by inspecting whether or not ink droplets are ejected from the nozzles to be inspected, the nozzles to be inspected eject ink droplets. A non-operating nozzle capable of ejecting ink droplets or a non-operating nozzle capable of ejecting ink droplets. If the non-operating nozzle is detected by the inspection, after the inspection according to a processing procedure selected by the user Execute the processing of. This makes it possible to select an appropriate processing procedure according to the situation according to the user's judgment.

The present invention relates to a printing method and apparatus, a computer program for realizing the functions of the method or apparatus, a recording medium on which the computer program is recorded, and a computer program including the computer program and embodied in a carrier wave. It can be realized in various modes such as signals. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic perspective view showing a main configuration of a color ink jet printer 20 as one embodiment of the present invention,

FIG. 2 is a block diagram showing an electrical configuration of the printer 20.

FIG. 3 is an explanatory diagram showing the configuration of the first dot missing inspection section 40 and the principle of the inspection method (flying drop inspection method).

FIG. 4 is an explanatory diagram showing another configuration of the first dropout inspection unit 40,

Fig. 5 shows the configuration of the third dot missing inspection unit 42 and its inspection method (diaphragm inspection method). Explanatory diagram showing the principle of

FIG. 6 is a flowchart showing the procedure of the printing process in the first embodiment.

FIG. 7 is an explanatory diagram showing an example of the complementary operation,

FIG. 8 is an explanatory diagram showing another example of the complementary operation,

FIG. 9 is a flowchart showing a printing procedure in the second embodiment.

FIG. 10 is a flowchart showing the procedure of the printing process in the third embodiment, FIG. 11 is a flowchart showing the procedure of the printing process in the fourth embodiment, and FIG. 12 is the procedure of the printing process in the fifth embodiment. FIG. 13 is an explanatory diagram showing an example of guidance display in the fifth embodiment,

FIG. 14 is a flowchart showing the procedure of the printing process in the sixth embodiment, and FIG. 15 is an explanatory diagram showing an example of the guidance display in the sixth embodiment. BEST MODE FOR CARRYING OUT THE INVENTION

Equipment configuration:

Next, embodiments of the present invention will be described based on examples. FIG. 1 is a schematic perspective view showing a main structure of a power inkjet printer 20 as one embodiment of the present invention. The printer 20 includes a paper stat force 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 step motor 30. And a guide rail 34 for a carriage 28. The carriage 28 is equipped with a print head 36 having a number of nozzles.

A first dot missing inspection unit 40 is provided at the first standby position of the carriage 28 at the right end in FIG. 1, and a second dot missing inspection unit is provided at the second standby position at the left end. 4 1 is provided. At the first standby position, a third missing dot inspection section 42 is further provided. The first dot missing inspection unit 40 includes a light emitting element 40a and a light receiving element 40b, and uses these elements 40a and 44b to fly ink droplets. Check for missing dots by checking the status. The second missing dot inspection section 41 also includes a light emitting element 41a and a light receiving element 41b, and inspects for missing dots according to the same principle as the first missing dot inspection section 40. The third missing dot inspection section 42 inspects for missing dots by checking whether or not the diaphragm provided on the surface vibrates with ink droplets. Detailed contents of the inspection by each dot missing inspection unit will be described later. The printing paper P is taken up by the paper feed roller 24 from the paper stapling force 22, and is sent 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 stepper 30 and moves in the main scanning direction along a 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 for receiving signals supplied from the host computer 100, an image buffer 52 for storing print data, and a system controller 5 for controlling the entire operation of the printer 20. 4 and have. The system controller 54 includes a main scanning drive driver 61 for driving the carriage motor 30, a sub-scanning driver 62 for driving the paper feed motor 31, and three dot missing inspection units 40 to 4. Inspection section drivers 6 3 to 65 that respectively drive the print heads 2, and head drive drivers 66 that drive the print heads 36 are connected.

The printer driver (not shown) of the host computer 100 determines various parameter values that define the printing operation based on the print mode (high-speed print mode, high-quality print mode, etc.) specified by the user. I do. The printer driver further generates a print data for performing 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 sends a control signal to each of the drivers 61 to 66 based on the information.

The print data received by the receive buffer memory 50 is stored in the image buffer 52. Image data of a plurality of color components obtained by decomposing each color component is stored. The head drive driver 66 reads the image data of each color component from the image buffer 52 according to the control signal from the system controller 54, and accordingly, the nozzle array of each color provided in the print head 36 is provided. Drive.

The function of the cleaning execution unit that performs cleaning of the print head 36 is realized by the system controller 54 and the head drive driver 66. The function of a complementary operation execution unit that performs a complementary operation described later is realized by the system controller 54, the main scanning driver 61, the sub-scanning driver 62, and the head driver 66. Is done.

B. Configuration and principle of the dropout inspection unit:

FIG. 3 is an explanatory diagram showing the configuration of the first dot dropout inspection section 40 and the principle of the inspection method (flying drop inspection method). Since the second dot dropout inspection section 41 has the same configuration and operation as the first dot dropout inspection section 40, the second dot dropout inspection section 41 will be described below. Is omitted. FIG. 3 is a view of the print head 36 viewed from the lower surface side. The nozzle array for the six colors of the print head 36 and the light emitting elements 40 a constituting the first dot missing inspection unit 40 are shown. And a light receiving element 40b.

On the lower surface of the print head 36, a black ink nozzle group K _D for ejecting black ink, a dark cyan ink nozzle group CD for ejecting dark cyan ink, and a dark ink group C _D for ejecting light cyan ink. Light cyan ink nozzle group C _L , dark magenta evening ink nozzle group M _D for ejecting dark magenta ink, light magenta ink nozzle group ML for ejecting light magenta ink, and ejecting yellow ink Yellow ink nozzle group II for. Are formed.

In addition, the capital letter of the first alphabet in the code indicating each nozzle group means the ink color, and the subscript “.” Indicates that the ink has a relatively high density, and the subscript “” Indicates that the ink has a relatively low density. Incidentally, subscript _"D" of Yellow ink nozzle group Y _D, that the yellow ink Ru ejected from the nozzle groups, a gray color when mixed by substantially equal amounts and concentrated Shianinku and dark magenta evening ink Means. The subscript of the black ink nozzle group K _D _"D", rather than the black ink ejected from these gray, which means that a concentration of 1 0 0% 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. This laser light L is emitted in parallel with the sub-scanning direction SS, and is received by the light receiving element 40b. When the dot dropout inspection, first, as shown in FIG. 3, the nozzle group of one color (e.g., dark yellow one Y _D) is head 3 to the printing position so that over the optical path of the laser beam L Position 6 In this state, dark yellow with the head driver 6 6 (2) - one by one nozzle of Y _D, and drives one by predetermined driving period, successively to eject ink droplets from the nozzles . The ejected ink droplet interrupts the optical path of the laser light L on the way, so that the light reception by the light receiving element 40b is temporarily interrupted. Therefore, if an ink droplet is normally ejected from a certain nozzle, the laser beam L is temporarily blocked by the light receiving element 40b, and it can be determined that the nozzle is not clogged. When the laser light L is not blocked at all during the driving period of a certain nozzle, it can be determined that the nozzle is clogged. It should be noted that it may not be possible to reliably detect whether or not the laser beam L has been cut off with one drop of ink, so it is preferable to discharge several drops per nozzle.

When all the nozzles for one color have been inspected for clogging, the print head 36 is moved slightly in the main scanning direction to inspect the nozzles for the next color (light magenta ML in the example in Figure 3). Execute

In this flying drop test method, the eye drops of each nozzle are detected by detecting ink drops in flight. Since the presence / absence of dot P (ie, the presence / absence of missing dots) is inspected, there is an advantage that the inspection is completed in a relatively short time.

FIG. 4 is an explanatory diagram showing another configuration of the first dot missing 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 direction of travel of the laser light L is such that when an ink droplet ejected from one nozzle is to be detected by the laser light L, the laser light L is blocked by an ink droplet ejected from another nozzle. It is set to not be performed. In other words, the optical path of the laser light L is set so as not to interfere with the paths of the ink droplets from the plurality of nozzles.

In this way, if the laser beam L is emitted in an oblique direction that is inclined from the sub-scanning direction SS, one nozzle can be used while moving the print head 36 slowly in the main scanning direction. The nozzles can be inspected for clogging by driving them one by one to eject ink droplets. This has the advantage that even if the ink droplets ejected from some nozzles deviate slightly from a prescribed position or direction, clogging of the nozzles can be inspected.

FIG. 5 is an explanatory diagram showing the configuration of the third dot missing inspection section 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 also shows a diaphragm 42a and a microphone 42b constituting a third dot dropout inspection unit 42. ing.

The piezo element PE provided for each nozzle n is installed at a position in contact with the ink passage 80 that guides the 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 in accordance with the expansion of the piezo element PE, and the ink droplet Ip is ejected at a high speed from the tip of the nozzle n.

When the ink droplet Ip discharged from the nozzle n reaches the diaphragm 42a, the diaphragm 42a vibrates. The microphone 42b converts the vibration of the diaphragm 42a into an electric signal. Replace. 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 diaphragm 42a (that is, whether or not the nozzle is clogged). .

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

Although FIG. 1 shows three missing dot inspection sections 40 to 42, it is sufficient that one dot missing inspection section is provided for one printer. However, in the case of a printer capable of performing bidirectional printing, it is preferable to provide one dropout inspection unit at each end of the main scanning range of the carriage 28. In this way, each time one main scan in the forward path is completed and each time one main scan in the return path is completed, the inspection can be performed by the dot missing inspection units at both ends. Therefore, dot dropout can be detected more quickly than when only one dot dropout inspection unit is provided.

The following various timings can be considered as the inspection timing for missing dots.

(1) Before starting a print job

(2) Every time one page is printed (before or after printing)

(3) Every single main scan (before main scan or after main scan)

(4) For each pixel (before or after recording a dot for one pixel)

If the dot missing inspection section shown in FIG. 1 is used, the inspection can be performed at the timings (1) to (3) described above. If the inspection is desired to be performed at the timing of (4) above, for example, a large number of sets of first dot missing inspection sections 40 are provided on the side surface of the carriage 28, and the It is sufficient that the light emitting element 40a and the light receiving element 40b sandwich the nozzle array. In order to detect missing dots as quickly as possible, it is desirable to perform the inspection for each pixel or for each main scan. In the present embodiment, since the dot missing inspection sections 40 to 42 are provided at both ends of the scanning range of the carriage 28, one time use of at least one of these inspection sections 40 to 42 is performed. The printing operation when the inspection is performed for each main scan will be described.

C. First Embodiment:

FIG. 6 is a flowchart illustrating the procedure of the printing process in the first embodiment. In the first embodiment, a dot missing inspection is performed before each main scan. In step S1, the dot missing inspection of all the six colors of nozzles is executed using the first dot missing inspection unit 40 while the carriage 28 is at the first standby position. In the following description, unless otherwise specified, the first dot omission inspection section 40 is used, but instead of this, the second and third dot omission inspection sections 41, 42 are used. Can also be used. If it is determined in step S2 that there is no missing dot, one-pass printing is executed in step S3. In this specification, one main scan during a printing operation is also referred to as a “pass”. In the case of bidirectional printing, one forward scan is one pass, and one return scan is one pass. When printing of one pass is completed, it is determined in step S6 whether or not printing of one page has been completed. If not completed, sub-scan feed of a normal printing operation is performed in step S7 and step S7 is performed. Return to S1.

If it is determined in step S2 that there is a missing dot, one-pass printing is performed in step S4, and then in step S5, a complementing operation of complementing the missing dot with another nozzle is performed. Execute.

FIG. 7 is an explanatory diagram illustrating an example of the supplementary operation. In FIG. 7, for simplicity, it is assumed that the print head 36 has only four nozzles, and that the second nozzle is a non-operation nozzle (a nozzle that is clogged). ) And the other nozzles It is a working nozzle (no clogging nozzle). Further, it is assumed that the nozzle pitch k is 3 dots, and that the sub-scan feed is performed at a constant feed amount F of 4 dots. FIG. 7A shows a printing operation when no complement is performed. Here, since the second nozzle is clogged, it is not possible to print the dots on the raster line indicated by the broken line in the first pass printing. If the complement operation is not performed, the printing of each pass will be performed one after another while no dot is formed on this raster line.

FIG. 7 (B) shows a printing operation when performing complementation. Missing dots occur in the first pass printing as in Fig. 7 (A). By the way, in the inspection at step S1 in FIG. 6, since it is detected that the second nozzle is a non-operation nozzle, it is also recognized that dot omission has occurred on the raster line indicated by the broken line. You. Therefore, in the complementary operation after the first pass (step S5), first, the sub-scan feed is performed with the transitional feed amount F a, and the last scan in which dot dropout occurs in the first pass is performed. Position the working nozzle on the line (indicated by the dashed line). In the example of FIG. 7 (B), the first nozzle is positioned on the raster line where the missing dot occurs by setting the transitional sub-scanning feed amount Fa to 3 dots. In this state, one-pass printing is performed, and a printing operation is performed on the raster line where the missing dots have occurred using the first nozzle. In order to perform such a supplementary operation, the print data of the first pass is retained in the image buffer 52 (Fig. 1) even after the printing of the first pass is performed, and the dot is omitted from the print data. The above supplementary operation is performed using the print data on the raster line where is generated. In the following, the main scan in which the complementary operation is performed is also referred to as a “complementary path”.

In the complementary pass, only the printing of dots on the raster line where the missing dots have occurred may be executed, but the printing of dots on other raster lines may also be executed at the same time. That is, in the complementary pass, dot recording is performed again on at least one raster line including at least a raster line where a missing dot has occurred. What should I do? However, if only the dot recording on the raster line with missing dots is performed, higher image quality can be achieved because the dots do not need to be overprinted on the normally printed raster line. There is an advantage. Another advantage is that ink can be saved.

In the procedure of FIG. 6, after performing one-pass printing in step S4, the complementary operation is performed in step S5, but this procedure may be reversed. That is, first, a normal one-pass printing may be performed after performing a complementing operation on a raster line where omission is likely to occur in normal one-pass printing.

When the complementary pass is completed, it is determined in step S6 whether printing for one page has been completed. If not completed, sub-scan feed is executed in step S7 and the process returns to step S1. However, as shown in FIG. 7 (B), the feed amount Fb of the sub-scan feed (second transient feed) performed after the complementary pass is the sum (F (F) of the feed amount Fa of the first transient feed. a + Fb) is set to be equal to the feed amount F in the normal printing operation. The “feed amount F in the normal printing operation” means a normal feed amount when no missing dots occur. Note that the feed amount F in a normal printing operation may be set to a different value for each pass. In this way, if the two transitional sub-scan feeds before and after the complementary pass are combined to achieve the same feed amount as the normal one sub-scan feed, the normal print operation can be performed next. The print head 36 can be correctly positioned at the position of the pass. Therefore, the missing dots can be easily complemented without changing the entire printing operation. The control of the supplementary operation as described above is executed by the system controller 54.

FIG. 8 is an explanatory diagram showing another example of the supplementary operation. In FIG. 8, it is assumed that the first nozzle is a non-operation nozzle and the other nozzles are operation nozzles. FIG. 8 (A) shows a printing operation when complementing is not performed, and FIG. 8 (B) shows a printing operation when complementing is performed. In this example, the inactive nozzle ノズル is the rearmost nozzle in the sub-scanning direction, so a positive value is set as the feed amount Fa for the first transient feed, Other operating nozzles cannot be positioned on the raster line where the dot dropout occurs. Therefore, the feed amount Fa of the first transient feed is set to a negative value (-3 dots in the example of Fig. 7 (B)), and missing dots occur in the second nozzle that is the other operating nozzle. Are positioned on the raster line. Then, the feed amount Fb of the second transient feed after the completion of the complementary pass is the sum of the feed amount Fa of the first transient feed (Fa + Fb), as in the case of FIG. Is set to be equal to the normal feed amount F.

In the case of FIG. 7, as in the case of FIG. 8, the feed amount Fa of the first excessive feed can be set to a negative value. However, a sub-scan feed with a negative feed amount (also called “back feed”) may include a relatively large feed error due to the backlash of the sub-scan feed mechanism. Since a large feed error degrades image quality, it is preferable to use positive values for the feed amounts F a and F b of the transient feed as much as possible.

In this way, if a missing dot test is performed before each pass, and if a non-operation nozzle is detected, a complementary operation is performed using another operation nozzle, a high-quality image with no dot omission can be obtained. Images can be printed.

D. Second embodiment:

FIG. 9 is a flowchart illustrating a procedure of a printing process according to the second embodiment. In the second embodiment, a dot missing inspection is performed after each main scan. After one-pass printing is performed in step S11, in step S12, dot missing inspection for all nozzles for six colors is performed using the first dot missing inspection unit 40.

If it is determined in step S13 that there is no missing dot, the process advances to step S15 to determine whether printing for one page is completed. If not completed, the sub-scan feed in the normal printing operation is executed in step S16, and the process returns to step S11.

If it is determined in step S13 that there is a missing dot, step S1 At 4, a complementary operation is performed by another nozzle. That is, the dots on the raster line where the missing dots have occurred are recorded by other operation nozzles. The specific method of the processing in step S14 is the same as that shown in FIGS. 7 and 8 described above. After this complementing operation, it is determined in step S15 whether printing for one page has been completed. If not, sub-scan feed is executed in step S16 and the process proceeds to step S11. Return. Thus, even if the inspection is performed after each scan, it is possible to print a high-quality image without missing dots.

In the first and second embodiments, missing dots are inspected each time scanning is performed, and when missing dots are detected, a complementary operation is performed using another operating nozzle. Therefore, even if a dot dropout occurs during one scan, the dot dropout can be detected immediately, and the dot dropout on the print medium can be easily eliminated.

E. Third Embodiment:

FIG. 10 is a flowchart showing the procedure of the printing process in the third embodiment. In the third embodiment, a dot missing inspection is performed before each main scan, and when dot missing is detected, nozzle cleaning is performed. In step S21, the first dot missing inspection unit 40 executes missing dot inspection of all nozzles for six colors. If it is determined in step S22 that there is no missing dot, one-pass printing is executed in step S23. When printing of one pass is completed, it is determined in step S29 whether or not printing of one page has been completed. If not completed, the sub-scan feed of the normal printing operation is performed in step S30. Execute and return to step S21.

If it is determined in step S22 that there is a missing dot, nozzle cleaning is executed in step S24. In this cleaning, all the nozzles of the print head 36 may be cleaned, or only the clogged nozzles may be cleaned.

In step S25, the missing dot inspection is executed again for all the nozzles. In step S26, if it is determined that all clogging of the nozzles has been eliminated and there is no missing dot, the process proceeds to step S23, and after performing one-pass printing, step S23 is performed. Move to 9. On the other hand, if it is determined that clogging of the nozzles has not been resolved and there is missing dots, after performing one-pass printing in step S27, the missing dots are removed in step S28. Executes the complementary operation to complement with other nozzles. The specific method of the processing in step S28 is the same as that shown in FIGS.

In the procedure of FIG. 10, after performing one-pass printing in step S27, the supplementary operation is performed in step S28, but this procedure may be reversed. That is, first, a normal one-pass printing may be performed after performing a supplementary operation on a raster line that is considered to be missing in normal one-pass printing. When the complementary pass is completed, it is determined in step S29 whether printing for one page has been completed. If not completed, sub-scan feed is executed in step S30 and step S21 Return to However, as shown in Fig. 7 (B), the feed amount Fb of the sub-scanning feed (second transient feed) performed after the complementary pass is the sum of the feed amount Fa of the first transient feed (Fa). F a + F b) is set to be equal to the feed amount F in a normal printing operation.

F. Fourth embodiment:

FIG. 11 is a flowchart illustrating the procedure of the printing process in the fourth embodiment. In the fourth embodiment, a dot missing inspection is performed after each main scan, and when dot missing is detected, nozzle cleaning is performed. First, after performing one-pass printing in step S31, in step S32, the first dot missing inspection unit 40 is used. CT / JP99 / 07386

Perform missing dot inspection for all nozzles for 16 colors.

If it is determined in step S33 that there is no missing dot, the flow shifts to step S39 to determine whether printing of one page has been completed. If not completed, the sub-scan feed in the normal printing operation is executed in step S40, and the process returns to step S31.

If it is determined in step S33 that there is a missing dot, nozzle cleaning is executed in step S34. In this cleaning, all the nozzles of the print head 36 may be cleaned, or only the clogged nozzles may be cleaned.

In step S35, the missing dot inspection is executed again for all the nozzles. If it is determined in step S36 that clogging of the nozzle has been resolved and there is no missing dot, the process proceeds to step S37, in which the missing dot is complemented by the original nozzle. Since the sub-scan feed is not performed between the printing of one pass in step S31 and the complementary operation in step S37, the print head 36 remains at the same sub-scan position. Therefore, the dot missing can be eliminated by re-executing the recording of the dot on the raster line where the dot missing has occurred using the nozzle from which the clogging has been eliminated. After eliminating the missing dots in step S37, the process proceeds to step S39, and if the printing of one page has not been completed, the sub-scan feed in the normal printing operation is executed in step S40. And return to step S31.

On the other hand, if it is determined in step S36 that clogging of the nozzles has not been eliminated and that there is a missing dot, in step S38, a complementary operation using another nozzle is performed. That is, the dots on the raster line where the missing dots are generated are recorded by other operation nozzles. The specific method of the process in step S38 is the same as that shown in FIGS. 7 and 8 described above. After this complementary operation, it is determined in step S39 whether printing for one page has been completed. If not completed, sub-scan feed is executed in step S40 and the process proceeds to step S31. Return. Thus, inspection after each scan It is also possible to print a high-quality image without dropouts. In the third and fourth embodiments described above, dot missing inspection is performed for each scan, and when dot missing is detected, nozzle cleaning is performed, and nozzle operation is restored by cleaning. If not, the complementary operation is performed using another operating nozzle. In addition, when the post-scanning inspection (Fig. 11) is performed, if the nozzle operation is recovered by cleaning, the complementary operation is performed using the recovered nozzle. Therefore, even if a missing dot occurs during one scan, the missing dot can be immediately detected, and the missing dot on the print medium can be easily eliminated.

G. Fifth Embodiment:

FIG. 12 is a flowchart showing the procedure of the printing process in the fifth embodiment. The procedure of the fifth embodiment is such that steps S41 and S42 are inserted between steps S33 and S34 of the fourth embodiment shown in FIG. This is the same as the fourth embodiment.

If a missing dot is detected (step S33), guidance for the user is displayed on the display of the host computer or the display panel of the printer in step S41. FIG. 13 is an explanatory diagram showing an example of the guidance display. In this guidance display, the description "Nozzle clogging has been detected in the printer. Please select the next processing procedure." And two buttons for the processing procedure 0 P1 and OP2 Is displayed. The first option O P1 is “J processing for complementing with another nozzle to continue printing,” and the second option O P2 is “processing for cleaning and complementing.”

When the user selects the first option 0P1, the process proceeds from step S42 to step S38, in which missing dots are complemented by other nozzles. On the other hand, when the user selects the second option OP2, the process proceeds from step S42 to step S34, where the nozzle Cleaning is performed. The processing after step S34 is the same as in the fourth embodiment. Note that the above-described guidance display and the selection of the processing procedure by the user can be similarly applied to the above-described first to third embodiments.

H. Sixth embodiment:

FIG. 14 is a flowchart illustrating the procedure of the printing process in the sixth embodiment. The procedure of the sixth embodiment is such that steps S41, 42, S34 to S38 of the fifth embodiment shown in FIG. 12 are replaced with steps S51 to S57. The other configuration is the same as that of the fifth embodiment.

If a missing dot is detected (step S33), guidance for the user is displayed in step S51. FIG. 15 is an explanatory diagram showing an example of guidance display in the sixth embodiment. This guidance display includes three alternatives 0 P11 to 0 P13 different from those in FIG. The first option 0 P 11 is a process of “reprinting from the top of the page after cleaning”, and the second option OP 12 is a process of “continue printing after cleaning”. The option OP 13 of the processing is “continue printing as it is”.

When the user selects the first option OP11, the process proceeds from step S52 to step S53, and it is determined whether or not the nozzle operation has been recovered by the predetermined number of cleanings. Specifically, each time one cleaning is completed, a dot missing inspection is performed, and when the nozzle recovers, the subsequent cleaning is stopped. When the nozzle is recovered by cleaning, the printing sheet is discharged in step S54, and printing is executed again from the top of the page. If the nozzle has not been recovered by the predetermined number of cleanings, the process proceeds from step S53 to step S55, and a warning is displayed on the display of the host computer or the display panel of the printer. Processing continues. This warning message indicates, for example, "clogging of nozzles cannot be recovered by cleaning, but printing has continued." Includes a description. It is preferable that such a warning be displayed even after printing is completed.

When the user selects the second option 0P12, the process moves from step 52 to step S56, and it is determined whether or not the operation of the nozzle has been recovered by the predetermined number of cleanings. When the nozzle is recovered, the printing process from step S39 is continued without performing the complementing process. On the other hand, if the nozzle does not recover, a warning is displayed in step S55, and then the processing in step S39 and thereafter is continued. If the user selects the third option 0P13, the process proceeds from step S52 to step S57, and after the warning is displayed, the process from step S39 continues. In the example of FIG. 14, when the nozzle is not recovered by cleaning, the printing process is continued without performing the complementing process. However, instead, the complementing operation may be performed by another operating nozzle. Alternatively, a warning may be displayed to interrupt the printing process.

In the above-described fifth and sixth embodiments, when a missing dot is detected, a guidance display for providing the user with a choice of a subsequent processing procedure is displayed. It is possible to select an appropriate processing procedure. Instead of displaying the guidance when a missing dot is detected, it is also possible to select a processing procedure after the detection of the missing dot before starting the print job. In this way, even if the user does not monitor the printing status during printing, it is possible to automatically execute the processing after the detection of the missing dot according to the processing procedure selected in advance.

I. Variations:

(1) In the above embodiment, part of the configuration realized by hardware may be replaced by software, and conversely, part of the configuration realized by software may be replaced by hardware. You may do so. Computer programs are stored on storage media such as floppy disks and CD-ROMs. And stored in a main memory (not shown) in the system controller 54. The system controller 54 executes the computer program to implement a part of the processing of each of the above-described embodiments.

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

(3) In the above embodiment, the dot missing inspection timing was described only for each pass, but the inspection timing may be set to various other timings during the printing operation for one page. It is possible. For example, it is possible to perform inspection after printing several passes. That is, the present invention is generally applicable to a case where a dot missing inspection is performed during a printing operation for one page.

In the above embodiment, all the nozzles are inspected in one inspection, but only one part of the nozzles may be inspected in one inspection. For example, in one inspection after one scan, about one third of the nozzles of each color may be inspected, and inspection of all nozzles may be completed by three inspections. Also, only the nozzles used in the print job need be inspected. For example, in monochrome printing, only the nozzles for black ink are to be inspected, and in color printing, nozzles for each color are to be inspected. As can be understood from the above description, in general, one dot missing inspection should be performed on at least some of the nozzles used in the print job.

(4) In the above embodiment, a case was described in which one printer is provided with three dot missing inspection units 40, 41, and 42. However, the dot missing inspection unit includes at least one dot missing inspection unit. It is sufficient if one is provided.

(5) In the above embodiment, when the clogging of the nozzle is not eliminated by one cleaning, the complementary operation by another nozzle is started. However, the clogging of the nozzle is also cleared by the cleaning more than twice. Start complementary operation for the first time when It may be. In other words, in general, when the clogging of the nozzles is not solved even after the predetermined number of cleanings, the complementary operation should be started.

(6) There are print media in which missing dots are conspicuous and those in which dots are inconspicuous. For example, printing paper for inkjet printing is more prone to missing dots, and ordinary copying paper is less prominent. Therefore, when using a printing medium in which dot omission is less noticeable, the complementing 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.

(7) Depending on the type of image to be printed, there are some types in which missing dots are conspicuous and some types in which dots are inconspicuous. For example, missing dots are easily noticeable in photographic images, but missing dots are less noticeable in text images containing only characters and graphic images composed of figures and characters such as graphs. 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-photo image, the complementing operation may not be performed until a predetermined number of nozzles are clogged. When adjusting the complementary operation according to the type of print image in this way, information indicating the type of print image may be registered in, for example, the header of print data sent from the computer to the printer. t

(8) There are also some printing modes in which missing dots are noticeable, and some that are not. For example, in the パス pass, there is a print mode in which only 1 の 4 of all pixels on some raster lines are recorded, and all the pixels on those raster lines are recorded in four passes. Exists. The greater the number of passes, the less likely missing dots are. Therefore, when the number of passes required to print all pixel positions on each raster line is a predetermined number or more, the complementing operation may not be performed until a predetermined number of nozzles are clogged.

(9) In a predetermined area near the end of the print area on the print medium, even if a missing dot is detected, the complementary operation by another nozzle is started immediately without performing cleaning. You may make it. For example, in the last area of about 13 (or about 14) of the printing paper, the complementary operation may be performed without performing cleaning. In this way, printing time may be reduced. Industrial applicability

INDUSTRIAL APPLICABILITY The present invention is applicable to printers and facsimile apparatuses that discharge ink from nozzles.

Claims

The scope of the claims

1. A printing method for printing an image by ejecting ink droplets from a plurality of nozzles at the time of main scanning and recording dots on the surface of a print medium,

(a) During the printing operation for one page, by inspecting whether or not ink droplets are ejected from the nozzles to be inspected, the nozzles to be inspected are operated by the nozzles capable of ejecting ink droplets and Determining whether or not the nozzle cannot be ejected and is out of alignment with the non-operating nozzle;

(b) performing a first supplementary operation of recording a dot to be recorded by the non-operation nozzle using another operation nozzle when the non-operation nozzle is detected by the inspection;

A printing method, comprising:

2. The printing method according to claim 1, wherein

The printing method, wherein the step (a) is performed for each main scan in a normal printing operation when the non-operation nozzle is not present.

3. The printing method according to claim 2, wherein

The printing method, wherein the first complementary operation is an operation of recording only dots on a main scanning line to be recorded by the non-operation nozzles by using the other operation nozzles.

4. The printing method according to claim 2, wherein

The step (b) comprises:

i) performing the sub-scan feed with a transient first feed amount before the first complementary operation, whereby the operating nozzle is placed on a main scanning line including a dot to be recorded by the non-operating nozzle. Positioning the ii) Positioning the plurality of nozzles at the nozzle position in the next main scan of the normal printing operation by performing sub-scan feed with a transient second feed amount after the first complementary operation. And a printing method, comprising:

5. The printing method according to claim 1, wherein

The step (b) comprises:

Performing the cleaning of at least the non-operational nozzle when the non-operational nozzle is detected by the inspection;

Performing the first supplementary operation in a case where the operation of the non-operation nozzle is not recovered by the predetermined number of cleanings;

A printing method comprising:

6. The printing method according to claim 5, wherein

7. The printing method according to claim 6, wherein

The step (b) further comprises:

When the non-operation nozzle is recovered by the cleaning within a predetermined number of times, the second complement for recording a dot that should have been recorded by the non-operation nozzle using the recovered operation nozzle. A printing method, comprising a step of performing an operation.

8. The printing method according to claim 7, wherein

The printing method, wherein the complementary operation is an operation of recording only a dot on a main scanning line to be recorded by the non-operation nozzle using the other operation nozzle or the recovered operation nozzle.

9. The printing method according to claim 6, wherein

The step (b) comprises:

i) performing the sub-scan feed with a transient first feed amount before the first complementary operation, whereby the operating nozzle is placed on a main scanning line including a dot to be recorded by the non-operating nozzle. Positioning the

ii) Positioning the plurality of nozzles at the nozzle position in the next main scan of the normal printing operation by performing sub-scan feed with a transient second feed amount after the first complementary operation. And a printing method, comprising:

10. A printing apparatus for printing an image by ejecting ink droplets from a plurality of nozzles at the time of main scanning and recording dots on the surface of a printing medium,

During the printing operation for one page, by inspecting whether or not ink droplets are ejected from the nozzles to be inspected, the nozzles to be inspected can eject ink droplets. An inspection unit for determining whether the nozzle is a nozzle or not;

When the non-operation nozzle is detected by the inspection, a complementary operation execution unit that performs a complementary operation of recording a dot to be recorded by the non-operation nozzle using another operation nozzle,

A printing device comprising:

11. The printing device according to claim 10, wherein

The printing apparatus, wherein the inspection unit performs the inspection for each main scan in a normal printing operation when the non-operation nozzle is not present.

12. The printing device according to claim 11, wherein The printing apparatus, wherein the first complementary operation is an operation of recording only dots on a main scanning line to be recorded by the non-operation nozzles by using the other operation nozzles.

13. The printing device according to claim 11, wherein

The complementary operation execution unit,

By performing sub-scan feed at a transient first feed amount before the first complementary operation, the operating nozzle is positioned on a main scanning line including a dot to be recorded by the non-operating nozzle. While positioning

By performing the sub-scan feed at the transient second feed amount after the first complementary operation, the plurality of nozzles are positioned at the nozzle positions in the next main scan of the normal printing operation. Printing device.

14. The printing apparatus according to claim 10, further comprising:

When the non-operation nozzle is detected by the inspection, a cleaning execution unit that performs cleaning of at least the non-operation nozzle,

The printing apparatus, wherein the supplementary operation execution unit executes the first supplementary operation when the operation of the non-operation nozzle is not recovered by the predetermined number of cleanings.

15. The printing device according to claim 4, wherein:

16. The printing device according to claim 15, wherein

When the non-operation nozzle is recovered by the cleaning within a predetermined number of times, the complementary operation execution unit uses the recovered operation nozzle to recover the dot that should have been recorded by the non-operation nozzle. A printing device that performs a second complementary operation to record.

17. The printing device according to claim 16, wherein

The printing apparatus, wherein the supplementary operation is an operation of recording only a dot on a main scanning line to be recorded by the non-operation nozzle using the other operation nozzle or the recovered operation nozzle.

18. The printing device according to claim 15, wherein

The complementary operation execution unit,

By performing sub-scan feed with a transient first feed amount before the first complementary operation, the operating nozzle is placed on a main scanning line including a dot to be recorded by the non-operating nozzle. While positioning

1 9. Computer program for executing printing on a computer equipped with a printing device that prints an image by ejecting ink droplets from a plurality of nozzles during main scanning and recording dots on the surface of a print medium A computer-readable recording medium recording

During the printing operation for one page, by inspecting whether or not ink droplets are ejected from the nozzles to be inspected, the nozzles to be inspected can eject ink droplets. An inspection function to determine whether the nozzle is a non-operational nozzle,

When the non-operation nozzle is detected by the inspection, a complementary operation execution function of performing a complementary operation of recording a dot to be recorded by the non-operation nozzle using another operation nozzle; A computer-readable recording medium that records a computer program for causing a computer to realize the above.

20. The recording medium according to claim 19, wherein

The recording medium, wherein the inspection is performed for each main scan in a normal printing operation when the non-operation nozzle is not present.

21. The recording medium according to claim 19, wherein the computer program further comprises:

A cleaning execution function of executing at least cleaning of the non-operation nozzle when the non-operation nozzle is detected by the inspection;

The recording medium, wherein the supplementary operation is performed when the operation of the non-operating nozzle is not recovered even after a predetermined number of times of the cleaning.

22. The recording medium according to claim 21, wherein:

23. A printing method for printing an image by ejecting ink droplets from a plurality of nozzles during main scanning and recording dots on the surface of a printing medium,

(a) During the printing operation for one page, by inspecting whether or not ink droplets are ejected from the nozzles to be inspected, the nozzles to be inspected are checked for the operation nozzles that can eject ink droplets and the ink droplets. Determining which of the non-working nozzles cannot be fired;

(b) performing the processing after the inspection according to the processing procedure selected by the user when the non-operation nozzle is detected by the inspection; A printing method, comprising:

24. The printing method according to claim 23, wherein:

The step (b) comprises:

Displaying the user to select one of a plurality of processing procedures, the processing after the inspection is performed according to a processing procedure selected by the user from the plurality of processing procedures, Printing method.

25. The printing method according to claim 23, wherein

A printing method, wherein the processing after the inspection is performed according to a processing procedure selected by a user from a plurality of processing procedures before printing is started.

26. A printing apparatus for printing an image by ejecting ink droplets from a plurality of nozzles at the time of main scanning and recording dots on the surface of a printing medium,

A control unit configured to execute processing after the inspection according to a processing procedure selected by a user when the non-operation nozzle is detected by the inspection;

A printing device comprising:

27. The printing device according to claim 26, further comprising:

A display unit for displaying one of a plurality of processing procedures for the user to select, wherein the control unit performs the processing after the inspection according to the processing procedure selected by the user from the plurality of processing procedures. A printing device that performs processing.

28. The printing apparatus according to claim 26, wherein:

The printing apparatus, wherein the control unit executes the processing after the inspection according to a processing procedure selected by a user from a plurality of processing procedures before printing is started.

2 9. A computer program for causing a computer equipped with a printing device that prints an image by ejecting ink droplets from a plurality of nozzles during main scanning to record dots on the surface of a print medium to execute printing A computer-readable recording medium recording

During the printing operation for one page, by inspecting whether or not ink droplets are ejected from the nozzles to be inspected, the nozzles to be inspected can eject ink droplets. An inspection function to determine which of the nozzles

A control function of executing processing after the inspection according to a processing procedure selected by a user when the non-operation nozzle is detected by the inspection;

A computer-readable recording medium on which a computer program for causing a computer to realize is stored.