JP6245322B2 - Liquid ejection apparatus, test pattern printing method, program - Google Patents

Description

  The present invention relates to a liquid ejecting apparatus, a print control apparatus, and a printing system that eject ink droplets, and more particularly, to a liquid ejecting apparatus, a print control apparatus, and a printing system that can perform banding adjustment.

In the banding adjustment, a predetermined mask pattern extending in the main scanning direction in a strip shape is printed side by side in the sub-scanning direction, and the amount of overlap is changed to obtain a correction amount of the medium feed amount.
Conventionally, what was disclosed by patent document 1 and patent document 2 is known as what performs such adjustment.
In these, the belt-like adjustment patch extending in the main scanning direction is fed together while changing the overlap amount little by little by feeding the feed amount little by little to the plus side and the minus side with respect to the reference amount. Then, the optimum value of the feed amount is detected by generating a white stripe and a black stripe based on the difference in the overlap amount at the boundary portion.

JP 2011-5875 A JP 2007-182080 A

In recent years, depending on the head of the liquid ejection device, the ink weight may vary depending on the ejection frequency. For example, the ink weight is about 20 at a half frequency (discharging duty is 50%) obtained by discharging dots one by one from the solid printing with respect to the solid printing (referring to a discharging duty of 100%). %. As the ink weight decreases, the dot diameter tends to decrease. Therefore, it may not be possible to say that the optimum feed amount is obtained by adjusting without taking such characteristics into consideration.
In this specification, “duty” means
・ "Ratio of number of dots to total number of pixels per unit area"
Or
・ "Coverage by dots (ink droplets) per unit area of media"
Point. Accordingly, the solid printing has a discharge duty of 100%, and when no printing is performed, the discharge duty is 0%. The full duty is 100% discharge duty. A mask pattern indicates the positions of dots that are actually ejected with respect to all positions where the dots can be ejected.

  The present invention provides a liquid ejection apparatus, a print control apparatus, and a printing system that perform banding adjustment that can obtain an optimum feed amount regardless of the ejection frequency.

  The present invention is a liquid ejecting apparatus that ejects ink droplets, and prints a predetermined mask pattern extending in a belt-like main scanning direction side by side in the sub-scanning direction, changes the degree of overlap, and corrects the feeding amount of the medium In order to obtain a quantity, a plurality of mask patterns with reduced ejection duties that do not overlap each other are used, and a single mask pattern is printed by performing overlay printing in a plurality of passes.

  In the above configuration, a plurality of mask patterns are overlay printed in a plurality of passes. Each mask pattern reduces the discharge duty and does not overlap each other. Since the ejection duty is reduced, the ink weight is reduced in the head having the characteristics described above. In addition, since the overlay printing does not overlap each other, the dot diameter does not increase. In this way, a plurality of mask patterns are printed and completed as one mask pattern.

  According to the present invention, it is possible to provide a mask pattern (adjustment patch) in consideration of a case where the ink weight decreases depending on the ejection duty. Then, the optimum feed amount can be adjusted using such a mask pattern.

1 is a block diagram of a printing system that includes a liquid ejection device and a printing control device (PC). It is a figure which shows the relationship between an ejection frequency and an ink weight. It is a figure which shows the mask pattern before overlay printing. It is a figure which shows the mask pattern after overlay printing. It is the figure printed by changing feed amount.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing a liquid ejecting apparatus and a printing control apparatus (PC) constituting a printing system according to an embodiment of the present invention.
In the figure, a liquid ejection apparatus 1 that ejects ink droplets is connected to an external personal computer (PC) 2 via an interface 3. The interface 3 is connected to a bus 4, and a head controller 5, a carriage motor 6, and a paper feed motor 7 are further connected to the bus 4. The head 8 is connected to the head controller 5 and controlled.

  In the PC 2, an operating system is operating, and a printer driver 2a is incorporated as a partial function thereof. The printer driver 2a generates and outputs print data for controlling printing by the liquid ejecting apparatus 1 based on printing source data output from the application. In addition to raster data for ejecting ink by turning each nozzle of the head 8 on and off, this print data is moved in the main scanning direction of the head 8 by the carriage motor 6 and in the sub-scanning direction of the medium by the paper feed motor 7. It also includes control data for controlling the feed amount.

FIG. 2 is a diagram illustrating the relationship between the ejection frequency and the ink weight. According to the graph shown in the figure, the ink weight is 0.8 Yng (nanogram) when the discharge frequency is X kHz (kilohertz), while the ink weight is 2 X kHz (kilohertz) when the discharge frequency is doubled. Changes to Yng (nanogram). In this case, 2X kHz is full duty.
Therefore, when the ejection duty is ½ of the full duty, the ink weight ratio is reduced by 20%.

FIG. 3 is a diagram showing a mask pattern before overlay printing. For convenience of understanding, black circles and white circles are displayed, but each is actually one dot.
Such a mask pattern is generated by the printer driver 2a in the personal computer (PC) 2. The printer driver 2a has an auxiliary function such as a utility in addition to a function of generating print data based on the print source data. As one of the functions, banding adjustment is included, and the following patches are printed on the printing paper as a predetermined medium feed amount. Further, feedback from the user is obtained, an optimum correction value is obtained, and this is reflected in the medium feed (control of the feed amount to the paper feed motor 7) in the subsequent printing.

I indicates the lower end side of the upper pattern portion of the predetermined mask pattern extending in the belt-like main scanning direction. In the drawing, the length corresponding to the upper four rasters is long and the length corresponding to the lower three rasters is short so that the length is changed, but the lengths in the main scanning direction are actually the same. . The upper portion corresponding to the upper four rasters is printed in one pass, and the shorter portion corresponding to the lower three rasters is printed in two passes of I and II.
As described above, the equivalent of four rasters printed in one pass has a discharge duty of 100%, a maximum discharge frequency (2X kHz), and a large ink weight (Yng). On the other hand, for the portion corresponding to 3 rasters printed in 2 passes, the ejection duty is 50%, the ejection frequency is halved (XkHz), and the ink weight is reduced by 20% (0.8 Yng).
On the lower end side of the upper pattern, the lower two rasters are mask patterns in which dots are arranged in a checkered pattern and the ejection duty is ½, and the upper one raster is two dots with no dots and with dots. It is a mask pattern that is made continuous to increase the visibility of the black van.

  The II mask pattern is a mask pattern overprinted by partial overlay printing on the I mask pattern. In this case, printing is performed in the second pass without feeding paper. The II mask pattern is an inverted pattern of the I mask pattern, and the discharge duty is 1/2 of the full duty and the discharge frequency is also 1/2, so the ink weight is reduced by 20% (0.8 Yng). .

In this three-raster part, the arrangement of dots is changed between the two-raster checkered part and the remaining one-raster part, but such a mode maintains the discharge duty and arranges the dots for each raster. Is equivalent to changing Further, the upper side of the upper pattern corresponds to a non-overlapping side when printed side by side, and a mask pattern in which dots are continuous on this side.
In the present embodiment, the overlay printing is premised on two-pass printing, and the mask pattern is a two-pass full-duty mask pattern by using mask patterns that are mutually inversion patterns that do not overlap each other. As an example, the mask pattern has a checkered pattern.

Further, the III mask pattern is obtained by inverting the I mask pattern up and down. The upper three rasters are mask patterns overprinted by partial overlay printing, and the lower four rasters are full-duty portions printed in one pass.
This mask pattern is on the upper end side of the portion that becomes the lower pattern of the predetermined mask pattern extending in the belt-like main scanning direction.
The upper two rasters are mask patterns in which dots are arranged in a checkered pattern and set to a discharge duty of 1/2 because the mask pattern of I is the upper and lower inverted patterns. This is a mask pattern in which the presence / absence is continued by 2 dots to increase the visibility of the black van.

  The IV mask pattern is a mask pattern overprinted by partial overlay printing on the II mask pattern, and is printed in the second pass without paper feeding. Since the IV mask pattern is an inverted pattern of the III mask pattern, the ejection duty is ½ of the full duty, the ejection frequency is also halved, and the ink weight is reduced by 20% (0.8 Yng).

  Thus, printing the three rasters at the lower end of the mask patterns I and II, and printing the three rasters at the upper end of the mask patterns III and IV are a plurality of mask patterns with reduced ejection duty that do not overlap each other. Is equivalent to printing one mask pattern by overlay printing in a plurality of passes. In addition, it can be said that the I and III mask patterns have a full-duty mask pattern in a raster unit.

  On the other hand, the above-described partial overlay printing on the lower end side of the upper pattern and the upper end side of the lower pattern means that overlay printing is performed within a range of rasters on the overlapping side when the mask patterns are printed side by side. It must be done.

FIG. 4 is a diagram showing a mask pattern after overlay printing. In this figure, the full duty part of the upper pattern is printed in one pass, then the I and II mask patterns are overprinted, and the medium is transported with the proper feed amount, and then the lower pattern and This shows a state in which the full duty portion of the lower pattern is printed in one pass after overlay printing of the mask patterns III and IV.
In the drawing, a portion indicated by A is a portion where the lower end portion of the upper pattern and the upper end portion of the lower pattern are in contact with each other. In these partially overprinted portions, compared with other full-duty printed portions, printing is performed in two passes at an ejection frequency of about ½, so that ink based on the frequency characteristics of the head 8 is printed. Weight reduction has occurred. Since the reduction in the ink weight appears as the line width becomes narrower after the reduction in the dot diameter, as a result, the part subjected to the partial overlay printing tends to appear as white banding.
For this reason, after such a part is dared to be printed on a part where the upper pattern and the lower pattern are in contact with each other, an adjustment is made so as to obtain an optimum feed amount.

FIG. 5 is a diagram printed with different feed amounts.
In the figure, nine patch pairs are printed from the top to the bottom on one sheet of printing paper (medium), and patch numbers 1 to 9 are assigned respectively from the top. Each patch pair is obtained by printing the upper pattern and the lower pattern shown in FIGS. 3 and 4 by adding a predetermined correction value δ in addition to the feed amount in which the lower end and the upper end are in close contact with each other. Here, the correction value δ itself is given by the patch numbers 1 to 9 which are increased in increments of −4 to +4.

This figure shows an ideal state in which no correction is required. When patch number = 5 and correction value δ = 0 is applied, no white stripe or black stripe occurs at the connection end portion.
Of course, printing such patch pairs with patch numbers 1 to 9 is a state in which a predetermined mask pattern extending in the belt-like main scanning direction is printed side by side in the sub-scanning direction, and the degree of overlap is changed. . The operation of obtaining a correction value δ corresponding to a patch that does not generate white or black streak with the naked eye corresponds to the operation of obtaining the optimum correction amount of the medium feeding amount.

In this embodiment, the overlay printing is premised on two-pass printing, but it is also possible to lower the discharge duty by printing in three passes. Finding the lowest ejection frequency according to the ejection frequency dependence characteristics of the head 8 and setting the ejection frequency to reproduce the line thinning when the ink weight is reduced most. For this purpose, it may be necessary to perform overlay printing in two or more passes.
In the above-described embodiment, the raster data is generated by the printer driver 2a. However, an equivalent function can also be performed inside the liquid ejecting apparatus 1. A conversion program may be provided in the cloud on the Internet.
In the above-described embodiment, the partial overlay printing is performed on the side where the upper pattern and the lower pattern are in contact with each other. If printing is performed at such a position, it is possible to independently observe a portion that is simply affected by line thinning. On the other hand, if it is provided at the end, the influence on the banding can be taken into account, and the overlay printing parts of both the upper pattern and the lower pattern are in contact with each other, so that the influence of line thinning can be easily recognized.

  Needless to say, the present invention is not limited to the above embodiments. It goes without saying that those skilled in the art will be able to apply the members and structures disclosed in the above-described embodiments that are interchangeable with each other by appropriately changing the combination thereof. However, it is a publicly known technique, and the members and configurations disclosed in the above-described embodiments can be replaced with members and configurations that are mutually interchangeable as appropriate, and the combination is changed and applied. Although not disclosed in the above, based on known techniques, those skilled in the art will appropriately replace the members and configurations that can be assumed as substitutes for the members and configurations disclosed in the above embodiments, and change the combinations thereof This is disclosed as an embodiment of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Liquid discharge apparatus, 2 ... Personal computer (PC), 2a ... Printer driver, 3 ... Interface, 4 ... Bus, 5 ... Head controller, 6 ... Carriage motor, 7 ... Paper feed motor, 8 ... Head

Claims (5)

A test for forming a dot on the medium by a head that moves relative to the medium in a first direction, and obtaining a correction amount of the medium feed amount in a second direction intersecting the first direction. A liquid ejection device for printing a pattern,
The test pattern has patches formed by first printing, second printing, third printing, and fourth printing,
The second printing and the third printing have more passes than the first printing and the fourth printing,
The printing area of the second printing and the third printing is located between the printing area of the first printing and the fourth printing,
The duty of the first printing and the fourth printing is Da, the duty of the second printing is Db, the duty of the third printing is Dc, and the number of passes for forming the dots in the second printing and the third printing A liquid ejection device that satisfies Db = Dc = Da / n, where n is n. The liquid ejection device according to claim 1,
The liquid ejection apparatus, wherein the number of passes for forming the dots in the first printing and the fourth printing is one. The liquid ejection device according to claim 1 or 2,
Of the print area of the second print and the print area of the third print, the raster that contacts the print area of the first print or the print area of the fourth print is the maximum frequency of the first print and the fourth print. A liquid ejection apparatus including a group of dots formed at the same frequency. The medium for a liquid ejection apparatus that forms dots on the medium by a head that moves relative to the medium in a first direction and conveys the medium in a second direction that intersects the first direction. A test pattern printing method for obtaining a feed amount correction amount,
The test pattern has patches formed by first printing, second printing, third printing, and fourth printing,
The second printing and the third printing have more passes than the first printing and the fourth printing,
The printing area of the second printing and the third printing is located between the printing area of the first printing and the fourth printing,
The duty of the first printing and the fourth printing is Da, the duty of the second printing is Db, the duty of the third printing is Dc, and the number of passes for forming the dots in the second printing and the third printing A test pattern printing method that satisfies Db = Dc = Da / n, where n is n. A test for forming a dot on the medium by a head that moves relative to the medium in a first direction, and obtaining a correction amount of the medium feed amount in a second direction intersecting the first direction. A program for controlling a liquid ejection apparatus for printing a pattern,
The test pattern has patches formed by first printing, second printing, third printing, and fourth printing,
The second printing and the third printing have more passes than the first printing and the fourth printing,
The printing area of the second printing and the third printing is located between the printing area of the first printing and the fourth printing,
The duty of the first printing and the fourth printing is Da, the duty of the second printing is Db, the duty of the third printing is Dc, and the number of passes for forming the dots in the second printing and the third printing Is a program for controlling the liquid ejection device so that Db = Dc = Da / n.

Images