JP2000280459A - Ink jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure printing having no missing of dot without replacing an ink cartridge even upon occurrence of a defective nozzle. SOLUTION: The ink jet printer comprises a sheet position control section 10 for locating the print position on a print sheet corresponding to a defective nozzle at the print position corresponding to a normal nozzle upon occurrence of a defective nozzle, and a dot moving section 11 for generating a dot data by moving the dot position in correspondence with the positional shift of the print sheet caused by locating the print position on the print sheet corresponding to the defective nozzle at the print position corresponding to the normal nozzle wherein a print head 4 prints a dot data generated from the dot moving section 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printer provided with a print head which moves in a direction perpendicular to the direction of movement of a printing paper. The present invention relates to an ink jet printer that uses a nozzle that can perform printing, and substitutes printing for a defective nozzle.

[0002]

2. Description of the Related Art In an ink jet printer, ink clogging easily occurs in nozzles provided in an ink cartridge. For this reason, when ink clogging occurs,
There is provided a removing unit that removes ink clogged in the nozzles by using a wiper and a removing unit that removes ink clogged in the nozzles by forcibly ejecting all the nozzles (first related art). And).

In the prior art proposed in Japanese Patent Application Laid-Open No. 8-267792, a first dielectric group consisting of a plurality of dielectric pieces arranged in parallel with the horizontal direction on a horizontal moving path of a carriage. Is provided. Further, a second dielectric group composed of a plurality of dielectric pieces arranged perpendicular to the horizontal direction is provided on the horizontal movement path of the carriage. Then, an ink adhesion position specifying unit is provided, and based on the positions of the pair of dielectric pieces that are short-circuited by the ink discharged toward the first dielectric group and the second dielectric group, the plurality of print heads are determined. The mutual positional relationship is calculated. Then, based on the calculated positional relationship, the nozzles used for ink ejection and the ejection timing are determined (referred to as a second related art).

[0004]

However, when the first prior art is used, the following problems have occurred. That is, since ink clogging has occurred in the nozzles, ink clogging may not be solved even when ink is removed using a wiper. Also, even when all nozzles are forcibly ejected, ink clogging may not be solved. If the ink clogging is not eliminated, dots are missing in the printing, resulting in deterioration of the printing quality. Therefore, when ink clogging occurs, it is necessary to replace the ink cartridge. But,
Since the ink cartridge is an expensive part, if you replace the ink cartridge every time ink clogging occurs,
This leads to an increase in running costs.

The second prior art is a technique for determining a nozzle to be used for ink discharge and a discharge timing based on the position of a pair of dielectric pieces where a short circuit has occurred. For this reason, in the case where ink clogging has occurred and a nozzle has become unable to eject ink, missing dots in printing cannot be prevented.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a nozzle capable of printing when a defective nozzle which cannot discharge ink occurs. An object of the present invention is to provide an ink jet printer capable of performing printing without missing dots without replacing an ink cartridge even when a defective nozzle occurs, by substituting printing for defective nozzles. .

Another object of the present invention is to provide a printing apparatus in which the printing paper feed direction is always set to a constant direction, so that the printing paper feed mechanism can perform printing even when backlash occurs. An object of the present invention is to provide an ink jet printer capable of preventing occurrence of a shift.

According to a third aspect of the present invention, in addition to the above objects, a test image capable of identifying whether each of a plurality of print heads is good or bad is printed, and a defective nozzle identified based on the test image is printed. It is an object of the present invention to provide an ink jet printer capable of easily specifying a defective nozzle without providing a complicated structure by providing an input means for instructing the nozzle.

[0009]

According to an aspect of the present invention, there is provided an ink-jet printer according to the present invention.
A print head provided with a plurality of print nozzles is applied to an ink jet printer that performs printing by moving in a direction orthogonal to a digit direction, which is a moving direction of print paper, and among print nozzles provided in the print head, When a print nozzle capable of ejecting ink is regarded as a normal nozzle, a print nozzle in which ink cannot be ejected is regarded as a defective nozzle, and when a defective nozzle occurs, a printing position on the printing paper corresponding to the defective nozzle is determined. And a paper position control unit that positions the printing position corresponding to the normal nozzle, and a position of the printing paper that is generated by positioning the printing position on the printing paper corresponding to the defective nozzle at the printing position corresponding to the normal nozzle. A dot moving unit that generates dot data in which the dot position is moved in accordance with the correction amount when the amount of deviation is used as the correction amount. The print head has a structure in which to print the dot data generated by the dot movement unit.

That is, the printing position on the printing paper corresponding to the defective nozzle for which ink ejection is disabled cannot be performed with dot data to be printed by the defective nozzle while being positioned at the printing position corresponding to the normal nozzle. Printing is performed by normal nozzles.

According to a second aspect of the present invention, in addition to the above configuration, in addition to the above-described configuration, the paper position control unit sets a print position on the print paper corresponding to the defective nozzle to a print position corresponding to a normal nozzle. The moving direction of the printing paper at the time of positioning is the same as the moving direction of the printing paper at the time of discharging the printing paper.

That is, the moving direction of the printing paper when the printing position on the printing paper corresponding to the defective nozzle is positioned at the printing position corresponding to the normal nozzle is the same as the moving direction of the printing paper when the printing paper is discharged. If they are the same, the printing paper is always moved in the same direction during the printing period. Therefore, even when a backlash occurs in the feed mechanism of the print sheet, the print sheet moves exactly following the movement amount to be sent by the feed mechanism.

According to a third aspect of the present invention, in addition to the above configuration, a test section for printing a test image capable of discriminating the quality of printing by each of the plurality of print nozzles, based on the test image. And an input unit to which data indicating the defective nozzle identified by the input is input.

That is, the test image may be any image as long as the quality of printing by each of the plurality of printing nozzles can be identified. In other words, it suffices if there is a print result corresponding to each of the print nozzles on a one-to-one basis and a display that associates each print result with each of the print nozzles. Therefore, a test image can be easily printed. Then, after printing the test image, the data input to the input unit may be handled as data indicating a defective nozzle.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below.
This will be described with reference to the drawings. FIG. 1 is a block diagram showing an electrical configuration of an embodiment of an ink-jet printer according to the present invention. The printer is mainly divided into a printer main body 1 that performs printing, and a computer unit that controls the printer main body 1. 2 is constituted.

In FIG. 1, a print head 4 is an ink cartridge provided with a plurality of print nozzles.
Each of the print nozzles is provided with a heating element for ejecting ink. The drive circuit 6 is a block for driving a heating element provided in the print head 4. In the present embodiment, the drive circuit 6 includes 13 address lines and 16 data lines.
Are driven. For this reason, the number of print nozzles provided in the print head 4 is 208.

The paper feeding section 3 is a block for moving the printing paper in the column direction. The control unit 5 is a block that controls the operation of the printer main body 1. Therefore, by controlling the operation of the paper feeding unit 3 in accordance with the command sent from the computer unit 2,
Move the printing paper. The dot data sent from the computer unit 2 is stored in 13 address lines and 1
The data is converted into data corresponding to the six data lines, and the converted data is sent to the drive circuit 6. The print head 4 is moved by a carriage (not shown) in a direction orthogonal to the moving direction (digit direction) of the printing paper.

The paper position control unit 10 is a block for calculating the feed amount of the printing paper and transmitting the calculation result to the control unit 5 via the communication unit 9. For this reason, the print head 4
If there are no defective nozzles in which ink can not be ejected from the print nozzles provided in the printer and all the print nozzles are normal nozzles that can eject ink, paper corresponding to 208 print nozzles is used. The transmission amount is sent to the control unit 5 via the communication unit 9. On the other hand, when a defective nozzle occurs,
The paper feed amount for positioning the print position on the print paper corresponding to the defective nozzle at the print position corresponding to the normal nozzle is calculated, and the calculated paper feed amount is transmitted to the control unit 5 via the communication unit 9. Send out.

Further, the paper position control unit 10 uses the shift amount of the print paper position caused by positioning the print position on the print paper corresponding to the defective nozzle at the print position corresponding to the normal nozzle as a correction amount. It is sent to the dot moving unit 11. When calculating the paper feed amount of the printing paper, the paper position control unit 10 calculates the paper feeding amount such that the moving direction of the printing paper is the same as the moving direction when discharging the printing paper. .

The data generating section 13 is a block for generating dot data for printing, and sends out the generated dot data to the dot moving section 11. When all of the print nozzles provided in the print head 4 are normal nozzles, the dot moving unit 11 controls the dot data sent from the data generation unit 13 via the communication unit 9 without changing the dot data. Send it to the unit 5. Also, the dot moving unit 11
When a defective nozzle occurs, the paper position control unit 10
The dot data is generated by shifting the dot position of the dot data output from the data generation unit 13 in the digit direction in accordance with the correction amount sent from. Then, the generated dot data is transmitted to the control unit 5 via the communication unit 9.

The test section 8 is a block for printing a test image (see FIG. 4) capable of discriminating the quality of printing by each of a plurality of print nozzles provided in the print head 4. The input unit 12 is a block composed of a keyboard, a mouse, or the like, and data indicating a defective nozzle identified based on the test image is 1 to 3.
It is input as a numerical value of 208. Then, the input numerical value is sent to the paper position control unit 10.

FIG. 2 is a flowchart showing the main operation of the embodiment, and FIG. 3 is an explanatory diagram showing print nozzles provided in the print head 4. Hereinafter, the operation of the embodiment will be described with reference to FIG. In the present embodiment, the printing nozzles are arranged in two rows, but for simplicity of description, FIG. 3 shows the printing nozzles arranged in one row. An arrow A shown in FIG. 3 indicates a moving direction of the printing paper when the printing paper is discharged. For this reason, in the following description, the print nozzle located closest to the discharge port among the plurality of print nozzles is referred to as the first print nozzle.

The input unit 12 is used to check whether or not there are defective nozzles in the 208 print nozzles P1 to P208 provided in the print head 4 so that ink cannot be ejected.
Then, when a test instruction is input, the test unit 8 performs control for printing a test image. Accordingly, 208 bars 42 corresponding to each of the print nozzles P1 to P208 are printed. Further, each of the bars 42 and each of the print nozzles P1 to P208 are
In order to make it possible to correspond to
Is printed. The numerical value 43 printed at this time is the numerical value 4
Nozzles P1 and P2 that have printed bars 42 corresponding to No. 3
08. Therefore, when the bar corresponding to the numerical value "4" is not printed, it is determined that the fourth print nozzle P4 is a defective nozzle.

Now, it is assumed that the numerical value "4" has been input to the input unit 12. As a result, the paper position control unit 10 determines that the printing nozzle P4 is a defective nozzle and the printing nozzles P1 to P3, P5 to P
It is determined that 208 is a normal nozzle. Then, the maximum value of the number of continuous normal nozzles is obtained from the determination result. In this case, the number of continuous normal nozzles is three and 204. For this reason, the paper position control unit 10
204 is calculated as the maximum value m (step S1).

Next, the paper position control unit 10 sets the total number of print nozzles P1 to P208 to N, and sets the calculated maximum value to m.
Then, in step S2, it is determined whether or not m ≧ N / 2-1 (the first expression) is satisfied (the reason will be described later). In this case, since the first expression is satisfied, the paper position control unit 10 calculates the paper feed amount of the print paper on the assumption that printing is performed using the 204 print nozzles of the print nozzles P5 to P208. .

That is, the paper feed amount for moving the print start position of the page to be printed to the print position corresponding to the print nozzle P5 is calculated. Therefore, the paper feed amount calculated at this time depends on all the print nozzles P1 to P208.
Is used, four print nozzles P1 to P1 are used.
The amount is reduced by P4. Therefore, the printing position 32 on the printing paper 31 corresponding to the defective nozzle P4 is located at the printing position 33 corresponding to the normal nozzle P8 (Step S3).

The shift amount (correction amount) of the printing paper 31 caused by positioning the printing position 32 on the printing paper 31 corresponding to the defective nozzle P4 at the printing position 33 corresponding to the normal nozzle P8 is 4 dots. Becomes Since the correction amount is 4 dots, the dot moving unit 11
3 among the dot data sent from the print nozzle P1
Is changed to dot data corresponding to the print nozzle P5. Hereinafter, similar changes are made. As a result, the dot data corresponding to the range 51 of the print nozzles P1 to P204 is changed to the dot data corresponding to the range 52 of the print nozzles P5 to P208 (should have corresponded to the defective nozzle P4). The dot data is dot data corresponding to the normal nozzle P8).
Next, the changed dot data is sent to the control unit 5 and printed by the print nozzles P5 to P208 (step S4).

When printing using the m print nozzles P5 to P208 is completed, the paper position control unit 10 sets the paper feed amount to an amount corresponding to the width of the m (204) print nozzles. Then, the printing paper 31 is fed (the printing paper 31 moves in the direction of arrow A). Therefore, the print nozzle P
In the print position corresponding to No. 5, the head of the range to be printed next is located. Therefore, also in this case, the printing position 32 on the printing paper 31 corresponding to the defective nozzle P4 is
It will be located at the print position 33 corresponding to the normal nozzle P8 (step S5).

Since the printing is not completed, the operation moves from step S6 to step S4. Therefore, before the dot data is changed, the dot moving unit 11
The dot data corresponding to the print nozzles P205 to P208 is changed to dot data corresponding to the print nozzles P5 to P8. Then, the newly obtained print nozzles P1 to P1
Among the dot data corresponding to P208, the dot data corresponding to the 200 print nozzles from the upper side is changed to the dot data from the ninth print nozzle to the 208th print nozzle P208. Therefore, printing using the m print nozzles P5 to P208 is restarted (step S4). Hereinafter, the same operation is repeated.

When printing of one page is completed, the operation moves from step S6 to step S13. Therefore, the paper position control unit 10 sends a command for moving the printing paper 31 in the direction of arrow A. As a result, the printing paper 31 moves in the direction of arrow A and is discharged.

The above operation is performed by the fourth print nozzle P4
Is an operation in the case of a defective nozzle. In general, when the number of defective nozzles is one, the maximum number of continuous normal nozzles is The value ranges from 104 to 207. Therefore, after the determination operation in step S2, the printing operation in step S3 is performed. Therefore, when there is one defective nozzle, the same operation as the above operation occurs. Further, the speed of the printing operation is in the range of 104/208 to 207/208 as compared to the speed when no defective nozzle is generated. Therefore, depending on the position where the defective nozzle is generated, a printing speed substantially equal to that in the normal state where no defective nozzle is generated can be obtained. In addition, even at the worst case, a speed that is half that of the normal case can be obtained.

The operation when one defective nozzle has occurred has been described above, and the operation when two defective nozzles have occurred will be described below.

When two consecutive print nozzles are defective, the maximum number of consecutive normal nozzles is:
The range is from 103 to 206. Therefore, after the determination operation of step S2, the operation of step S3 is performed, and the same operation as the above operation is performed. The speed of the printing operation is in the range of 103/208 to 206/208 compared to the speed when no defective nozzle is generated. Therefore, depending on the position where the defective nozzle is generated, a printing speed that is almost the same as in the normal state can be obtained. In addition, even at the worst case, the speed is almost half that of the normal case.

On the other hand, when two defective nozzles occur at positions separated from each other, the maximum value of the number of continuous normal nozzles is in the range of 69 to 206. Therefore, when the maximum value is in the range of 103 to 206, the same operation as described above is performed. On the other hand, when the maximum value is in the range of 69 to 102, an operation different from the above is performed. As an example, a case where the 52nd print nozzle P52 and the 125th print nozzle P125 become defective nozzles will be described.

When the above-mentioned defective nozzle occurs, the maximum value of the number of continuous normal nozzles is 82. Therefore,
The operation moves from step S2 to step S7. As a result, the paper position control unit 10 moves the print paper 31 in the direction of arrow A with the same paper feed amount as in normal operation (when no defective nozzles are generated) in order to start printing a new page. For this reason, the print start position is determined by the print nozzle P
1 is located at the printing position corresponding to 1. In this state, the dot moving unit 11 does not change the dot data provided from the data generating unit 13 (or changes the dot data corresponding to the print nozzles P52 and P125 to data that does not eject ink). ), And sends it out to the control unit 5 via the communication unit 9. Therefore, the print nozzle P
Printing is performed by the print nozzles P1 to P208 excluding 52 and P125 (step S8).

Next, the paper position control unit 10 moves the print paper 31 by an arrow A by a distance corresponding to one print nozzle.
Move in the direction. As a result, the printing position 34 on the printing paper 31 corresponding to the printing nozzle (defective nozzle) P52
Is located at the print position 35 corresponding to the 51st print nozzle (normal nozzle) P51. Similarly, the printing position (not shown) on the printing paper 31 corresponding to the printing nozzle (defective nozzle) P125 is located at the printing position corresponding to the 124th printing nozzle (normal nozzle) ( Step S9).

Since the correction amount becomes one dot by the above movement of the printing paper 31, the dot moving unit 11 sets the dot data among the dot data given for printing in step S8.
The dot data for the print nozzle P52 is changed to the dot data for the print nozzle P51. Further, the dot data for the print nozzle P125 is changed to dot data for the 124th print nozzle. Then, the other dot data is changed to dot data that is not printed. Therefore, the printing paper 3 corresponding to the printing nozzle P52
1, printing is performed by the printing nozzle P51, and the printing paper 3 corresponding to the printing nozzle P125 is printed.
Printing is performed by the 124th printing nozzle at the printing position on the top (step S10).

When the complementary printing in step S10 is completed, the paper position control unit 10 feeds the print paper at a paper feed amount corresponding to 207 print nozzles (step S11). As a result, the leading position of the next print is located at the print position corresponding to the print nozzle P1. Therefore, the operation from step S8 is restarted thereafter. Then, when the last of one page is printed, the operation moves from step S12 to step S13. Therefore, the paper position control unit 10 sends a command for moving the printing paper 31 in the direction of arrow A.
As a result, the printing paper 31 moves in the direction of arrow A and is discharged. In addition, the printing speed when performing the above operation is about half the speed when no defective nozzle is generated.

As described above, when the operation shifts from step S2 to step S7, if the first print nozzle P1 becomes a defective nozzle, no print is made at the print position on the print paper corresponding to the print nozzle P1. Inconvenience occurs. However, when the first print nozzle P1 is a defective nozzle, the maximum value is 103 or more regardless of the position of another defective nozzle. Therefore, when the operation proceeds to step S7, it is guaranteed that the first print nozzle P1 is a normal nozzle. Therefore, the occurrence of the above-described inconvenience is prevented.

In this embodiment, when the number of defective nozzles becomes three or more, a message indicating that the ink cartridge needs to be replaced is displayed and printing is not performed. However, even when three or more defective nozzles are generated, it is possible to perform printing using the normal nozzles at the print position on the printing paper corresponding to the defective nozzles in the same manner as the above operation. It has become.

As for the number of print nozzles, 20
Although the case where the number is eight has been described, the same can be applied to other numbers.

[0042]

According to the first aspect of the present invention, among the plurality of print nozzles provided in the print head, a print nozzle capable of ejecting ink is regarded as a normal nozzle, and it is determined that ink cannot be ejected. When a defective nozzle is used as a defective nozzle,
A paper position control unit that positions a printing position on printing paper corresponding to a defective nozzle at a printing position corresponding to a normal nozzle, and a printing position on the printing paper corresponding to the defective nozzle that corresponds to a normal nozzle. When a shift amount of the position of the printing paper caused by being located at the correction amount, a dot moving unit that generates dot data by moving the dot position corresponding to the correction amount, the print head, The printing of the dot data generated by the dot moving unit is performed. Therefore, the printing position on the printing paper corresponding to the defective nozzle for which ink ejection has been disabled is located at the printing position corresponding to the normal nozzle, and is provided with dot data to be printed by the defective nozzle. Printed. For this reason, even when a defective nozzle occurs, printing without missing dots can be performed without replacing the ink cartridge.

Also, in the ink jet printer according to the present invention, when the paper position control unit positions the print position on the print paper corresponding to the defective nozzle at the print position corresponding to the normal nozzle. The moving direction of the printing paper is the same as the moving direction of the printing paper when the printing paper is discharged. Therefore, the printing paper always moves in the same direction during the printing period. For this reason, even when a backlash occurs in the printing paper feed mechanism, the printing paper moves exactly following the movement amount that the feeding mechanism intends to send, and the printing paper feed mechanism has a backlash. This also makes it possible to prevent the occurrence of printing misalignment even when the occurrence of occurs.

According to a third aspect of the present invention, there is provided an ink jet printer, comprising: a test section for printing a test image capable of discriminating whether or not printing is performed by each of the plurality of print nozzles, and a defect identified based on the test image. And an input unit to which data indicating the nozzle is input. For this reason, after printing a test image that can be easily created, the data input to the input unit may be handled as data indicating a defective nozzle. The nozzle can be specified.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electrical configuration of an embodiment of an ink jet printer according to the present invention.

FIG. 2 is a flowchart showing a main operation of the embodiment.

FIG. 3 is an explanatory diagram showing print nozzles provided in a print head arranged in one line.

FIG. 4 is an explanatory diagram showing a test image.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Printer main body 2 Computer part 4 Print head 8 Test part 10 Paper position control part 11 Dot moving part 12 Input part 31 Printing paper 32, 34 Printing position on printing paper corresponding to defective nozzle 33, 35 Printing corresponding to normal nozzle Position 42 Bar printed by each of the print nozzles 43 Numerical value indicating the print nozzle corresponding to the bar A Print paper discharge direction P1 to P208 Print nozzles S4, S10 Steps for substituting the prints of defective nozzles with normal nozzles

Claims (3)

[Claims] 1. An ink jet printer in which a print head provided with a plurality of print nozzles performs printing by moving in a direction orthogonal to a digit direction which is a moving direction of print paper, wherein the print nozzle provided in the print head is provided. When the print nozzle capable of ejecting ink is regarded as a normal nozzle, the print nozzle in which ink cannot be ejected is regarded as a defective nozzle, and when a defective nozzle occurs, the print nozzle corresponding to the defective nozzle is placed on the printing paper. A paper position control unit that positions the printing position of the printing paper corresponding to the normal nozzle, and the printing that is performed by positioning the printing position on the printing paper that corresponds to the defective nozzle to the printing position corresponding to the normal nozzle. When the shift amount of the paper position is used as the correction amount, a dot for generating dot data in which the dot position is moved according to the correction amount is set. And a moving portion, the printing head is an ink jet printer and performing printing of the dot data generated by the dot movement unit. 2. The printing apparatus according to claim 1, wherein the paper position control unit controls a moving direction of the printing paper when the printing position on the printing paper corresponding to the defective nozzle is positioned at a printing position corresponding to the normal nozzle. 2. The ink jet printer according to claim 1, wherein the printing paper is moved in the same direction as when the paper is ejected. 3. A test unit for printing a test image capable of discriminating the quality of printing by each of the plurality of print nozzles, and an input unit for inputting data indicating a defective nozzle identified based on the test image. The inkjet printer according to claim 1 or 2, further comprising: