JP2005138499A - Liquid discharging apparatus, printing controlling apparatus, program, liquid discharging method and liquid discharging system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To decrease liquid droplets discharged toward a region separated from a medium, and to prevent a paper at a part where the liquid droplets are decreased for discharging from being dimly printed when positional deviation occurs during carrying the paper. <P>SOLUTION: A liquid discharging apparatus equipped with a liquid discharging part for discharging the liquid droplets toward the medium to form dots on the medium, is characterized by that it is possible to discharge the liquid droplets from the liquid discharging part by decreasing the total amount of the liquid droplets to be discharged toward a prescribed region near the end part of the medium, and a difference between the total amount of the liquid droplets to be discharged in a certain prescribed region and the total amount of the liquid droplets actually discharged, is smaller than the difference in the other region where the total amount of the liquid droplets to be discharged is larger than that in the prescribed region. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a liquid ejection apparatus, a printing control apparatus, a program, a liquid ejection method, and a liquid ejection system.

An ink jet printer is known as one of liquid ejecting apparatuses that eject liquid droplets toward a medium. This ink jet printer forms a large number of dots on a printing paper by ejecting ink droplets as liquid droplets toward a printing paper (hereinafter also referred to as paper) as a medium, and a macroscopic image is formed by these dots. It is something to print.
This ink jet printer has a printing function of “marginless printing”. This is a function for printing an image without forming a margin on the paper by forming dots over the edge of the paper. In order to prevent an unintended dot-unformed portion from occurring at the edge of the paper due to paper misalignment at the time of printing, etc. Liquid droplets are also ejected to areas that are outside.
JP 20022252531 A

However, most of the liquid droplets ejected toward the deviated area are discarded without forming dots on the paper, and the amount of ink used is increased. Therefore, it is conceivable to reduce the number of liquid droplets ejected toward the area that is removed.
However, when the liquid droplets in the region where the number of ejected liquid droplets is small are reduced, if the positional deviation occurs during paper conveyance, the liquid droplets are reduced and the ejected portion of the paper is printed thinly. there were.

  The present invention has been made in view of the above circumstances, and reduces the number of liquid droplets ejected toward an area that is removed from the medium, and reduces the amount of liquid droplets that are ejected when misalignment occurs during paper conveyance. This is to prevent the printed paper from being printed thinly.

  A main invention for achieving the above object is to provide a liquid ejecting apparatus including a liquid ejecting unit for ejecting liquid droplets toward a medium so as to form dots on the medium, and a predetermined region near an end of the medium. It is possible to reduce the total amount of liquid droplets to be discharged toward the surface and discharge the liquid droplets from the liquid discharge unit, and actually discharge the total amount of liquid droplets to be discharged in a predetermined region The difference from the total amount of liquid droplets is smaller than the difference in the other region where the total amount of liquid droplets to be discharged is larger than the predetermined region.

  Other features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

  To reduce the number of liquid droplets ejected toward the area outside the medium, and to prevent the printed portion of the paper from being thinly printed by reducing the liquid droplets when misalignment occurs during paper transport Is possible.

  At least the following matters will become apparent from the description of this specification and the accompanying drawings.

In a liquid ejection apparatus having a liquid ejection section for ejecting liquid droplets toward a medium to form dots on the medium, the total amount of liquid droplets to be ejected toward a predetermined region near the end of the medium The liquid droplets can be ejected from the liquid ejection unit, and the difference between the total amount of liquid droplets to be ejected and the total amount of liquid droplets actually ejected in a certain region is the predetermined amount. A liquid ejecting apparatus, wherein the difference is smaller than the difference in another region where the total amount of liquid droplets to be ejected is larger than the region.
In such a liquid ejecting apparatus, it is possible to reduce the total amount of liquid droplets to be ejected toward a predetermined region near the edge of the medium and eject the liquid droplets from the liquid ejecting unit. The difference between the total amount of liquid droplets to be ejected in a certain predetermined area and the total amount of liquid droplets to be actually ejected is the difference in the other area where the total amount of liquid droplets to be ejected is larger than that predetermined area. Since the difference is smaller than the difference, the total amount of liquid droplets to be ejected toward a predetermined area near the edge of the medium is reduced, and when a positional deviation occurs during paper conveyance, the liquid droplets are reduced and ejected. It is possible to prevent the printed paper from being printed thinly.

When the total amount of liquid droplets to be ejected toward a predetermined area near the edge of the medium is larger than a predetermined threshold, the liquid ejection unit reduces the total amount of liquid droplets and moves the liquid toward the predetermined area. When the total amount of liquid droplets to be discharged toward a predetermined region near the edge of the medium is smaller than a predetermined threshold, the liquid is directed toward the predetermined region without reducing the total amount of liquid droplets. It is preferable to eject droplets.
In such a liquid ejecting apparatus, the liquid ejecting section is configured so that when the total amount of liquid droplets to be ejected toward a predetermined area near the edge of the medium is larger than a predetermined threshold, When the total amount of liquid droplets to be discharged toward the predetermined region near the edge of the medium is smaller than a predetermined threshold when the total amount is reduced and the liquid droplets are discharged toward the predetermined region, the total amount of liquid droplets When the liquid droplets are ejected toward the predetermined area without reducing the amount of liquid droplets, the total amount of liquid droplets to be ejected toward the predetermined area near the edge of the medium is reduced, and misalignment occurs during paper conveyance. In addition, it is possible to prevent the portion of the paper ejected by reducing the liquid droplets from being thinly printed.

It is preferable that the total amount of liquid droplets to be ejected toward a predetermined region near the edge of the medium is reduced by a predetermined ratio, and the liquid droplets are ejected from the liquid ejection unit.
In such a liquid ejecting apparatus, the total amount of liquid droplets to be ejected toward a predetermined region near the edge of the medium is reduced by a predetermined ratio, and the liquid droplets are ejected from the liquid ejecting unit. Therefore, the total amount of liquid droplets to be ejected toward a predetermined area near the edge of the medium is reduced, and when the positional deviation occurs during paper conveyance, the portion of the paper in which the liquid droplets are reduced and ejected Can be prevented from being printed thinly.

When the liquid droplets are ejected from the liquid ejection unit toward a predetermined area near the edge of the medium, an appropriate number of liquid droplets are thinned and ejected from the liquid droplets to be ejected toward the area. It is preferable.
In such a liquid ejecting apparatus, when the liquid droplet is ejected from the liquid ejecting unit toward a predetermined region near the end of the medium, the liquid droplets to be ejected toward the region Therefore, it is possible to reduce the number of liquid droplets ejected toward an area outside the medium.

When ejecting the liquid droplets from the liquid ejection unit toward a predetermined area near the edge of the medium, at least one of the liquid droplets to be ejected is changed to a smaller liquid droplet and ejected. It is preferable to do.
In such a liquid ejecting apparatus, when ejecting the liquid droplets from the liquid ejecting unit toward a predetermined region near the end of the medium, at least one of the liquid droplets to be ejected, Since the liquid droplets are changed into smaller droplets and ejected, it is possible to reduce the number of liquid droplets ejected toward the region that is out of the medium.

The predetermined area near the edge of the medium is an area that deviates from a reference area corresponding to the size of the medium, stores the reference area, and is based on image data formed in a size larger than the reference area. It is preferable to discharge the liquid droplets.
In such a liquid ejecting apparatus, the predetermined area near the edge of the medium is an area that deviates from a reference area corresponding to the size of the medium, stores the reference area, and is larger than the reference area. Since the liquid droplets are ejected based on the image data formed in a large size, it is possible to form an image up to the edge of the medium. That is, an image can be formed without a border.

The liquid ejection unit includes a nozzle that ejects the liquid droplet, and ejects the liquid droplet while moving the nozzle, thereby forming a raster line in which a large number of dots are aligned in a straight line, and the image data It is preferable that the image formed on the medium based on the medium is configured in parallel at a predetermined interval in a direction in which the raster line intersects the raster line direction.
In such a liquid ejecting apparatus, the liquid ejecting section includes a nozzle that ejects the liquid droplet, and by ejecting the liquid droplet while moving the nozzle, a large number of dots are aligned in a straight line. An image formed on a medium based on the image data is formed by arranging the raster lines in parallel at a predetermined interval in a direction intersecting the raster line direction. Can be formed.

It is preferable that the rate at which the liquid droplets are reduced increases toward the end in the raster line direction.
In such a liquid ejecting apparatus, the rate at which the liquid droplets are reduced increases toward the end in the raster line direction, so the number of liquid droplets can be reduced while effectively suppressing deterioration in image quality. can do.

It is preferable to reduce the liquid droplets in the direction intersecting the raster line from the extreme end in the raster line direction.
In such a liquid ejecting apparatus, the liquid droplets are reduced in the direction intersecting the raster line from the extreme end in the raster line direction. Can be reduced.

It is preferable to reduce the liquid droplets for each raster line.
In such a liquid ejection apparatus, the number of liquid droplets is reduced for each raster line, so that the number of liquid droplets can be reduced while effectively suppressing deterioration in image quality.

A support member configured to support the medium when the liquid droplets discharged from the liquid discharge unit land on the medium, and the support unit includes a recess corresponding to a region determined to be detached from the medium; It is preferable that the medium is supported by a convex portion of the support member.
Such a liquid ejecting apparatus includes a support member for supporting the medium when the liquid droplet ejected from the liquid ejecting section is landed on the medium. A recess is formed corresponding to a region determined to be detached, and the medium is supported by the convex portion of the support member, so that the liquid droplet ejected toward the region determined to be detached from the medium Is collected in the concave portion, and the medium is supported by the convex portion.

The liquid droplet is preferably an ink droplet.
In such a liquid ejecting apparatus, since the liquid droplet is an ink droplet, it can be printed on a medium using ink.

It is preferable to perform borderless printing on the medium.
In such a liquid ejecting apparatus, borderless printing can be performed on the medium.

In addition, in a liquid ejection apparatus having a liquid ejection section for ejecting liquid droplets toward the medium to form dots on the medium, the liquid droplets to be ejected toward a predetermined region near the end of the medium It is possible to discharge the liquid droplets from the liquid discharge unit, and the difference between the total amount of liquid droplets to be discharged in a predetermined region and the total amount of liquid droplets actually discharged is The liquid ejecting section is smaller than the difference in the other area where the total amount of the liquid droplets to be ejected is larger than the predetermined area, and the liquid ejecting portion is ejected toward the predetermined area near the end of the medium When the total amount of droplets is larger than a predetermined threshold, the total amount of liquid droplets is reduced, the liquid droplets are discharged toward the predetermined region, and the liquid droplets to be discharged toward the predetermined region near the edge of the medium When the total amount of is less than a predetermined threshold In the case where the liquid droplets are discharged toward the predetermined region without reducing the total amount of liquid droplets, and the liquid droplets are discharged from the liquid discharge unit toward the predetermined region near the edge of the medium, An appropriate number of liquid droplets are thinned and discharged from the liquid droplets to be discharged toward the region, and the predetermined region in the vicinity of the end of the medium is a region deviating from a reference region corresponding to the size of the medium. The reference area is stored, the liquid droplets are ejected based on image data formed in a size larger than the reference area, and the liquid ejection section includes a nozzle that ejects the liquid droplet, and moves the nozzle By ejecting liquid droplets, a raster line in which a large number of dots are aligned on a straight line is formed, and an image formed on a medium based on the image data has the raster line in the raster line direction. It is configured in parallel in the intersecting direction at a predetermined interval, and as it goes toward the end in the raster line direction, the rate of reducing the liquid droplets increases, and in the direction intersecting the raster line from the extreme end in the raster line direction, The liquid droplets are reduced, and when the liquid droplets ejected from the liquid ejection unit land on the medium, a support member is provided for supporting the medium, and the support unit is determined to be detached from the medium. A concave portion is formed corresponding to a region, the medium is supported by a convex portion of the support member, the liquid droplet is an ink droplet, and borderless printing is performed on the medium. It is also possible to realize a liquid ejection device.
In this way, the effects of the present invention can be achieved most effectively because all the effects described above can be achieved.

Further, by reducing the total amount of liquid droplets to be ejected from the liquid ejection unit toward a predetermined region near the edge of the medium, the liquid droplets are ejected, and the total amount of liquid droplets to be ejected in a certain region Also realized is a printing control device characterized in that the difference from the total amount of liquid droplets actually ejected is smaller than the difference in other regions where the total amount of liquid droplets to be ejected is larger than the predetermined region. Is possible.
The print control apparatus realized in this way is a print control apparatus superior to the conventional one.

In addition, the printing apparatus has a function of reducing the total amount of liquid droplets to be ejected toward a predetermined region near the edge of the medium, and ejecting the liquid droplets, and the total amount of liquid droplets to be ejected in a predetermined region The function of ejecting liquid droplets so that the difference between the actual amount of liquid droplets actually ejected is smaller than the difference in other regions where the total amount of liquid droplets to be ejected is larger than the predetermined region. A program for realizing the above can also be realized.
The program executed in this way is a program superior to the conventional program.

Further, in the liquid ejection method for ejecting liquid droplets toward the medium in order to form dots on the medium, the total amount of liquid droplets to be ejected toward a predetermined region near the edge of the medium is reduced, and the liquid The difference between the total amount of liquid droplets to be ejected in a given area and the total amount of liquid droplets actually ejected is different from that in which the total amount of liquid drops to be ejected is larger than that predetermined area. It is also possible to realize a liquid ejection method characterized by ejecting liquid droplets so as to be smaller than the difference in the region.
The printing method realized in this way is a better method than the conventional method.

Further, the liquid ejection system includes a computer main body and a liquid ejection device connectable to the computer main body, and the liquid ejection device is a liquid to be ejected toward a predetermined region near the end of the medium. It is possible to reduce the total amount of droplets and eject the liquid droplets from the liquid ejection unit, and the difference between the total amount of liquid droplets to be ejected and the total amount of liquid droplets actually ejected in a given region is Also, a liquid ejection system characterized by being smaller than the difference in the other area where the total amount of liquid droplets to be ejected is larger than the predetermined area can be realized.
The printing system realized in this way is a system superior to the conventional system as a whole system.

=== Overview of Liquid Discharge Device ===
An outline of an ink jet printer will be described as an example of the liquid ejection apparatus according to the present invention. 1-4 is a figure for demonstrating the outline | summary of one Embodiment of the inkjet printer 1. FIG. FIG. 1 shows the appearance of an embodiment of the inkjet printer 1. FIG. 2 shows a block configuration of the inkjet printer 1, and FIG. 3 shows a carriage of the inkjet printer 1 and its peripheral portion. FIG. 4 shows the transport unit and its peripheral part of the inkjet printer 1.

  As shown in FIG. 1, the ink jet printer 1 has a structure for discharging a printing paper S as a medium supplied from the back side from the front side, and an operation panel 2 and a paper discharge unit 3 are provided on the front side. The sheet feeding unit 4 is provided on the back side. Various operation buttons 5 and display lamps 6 are provided on the operation panel 2. Further, the paper discharge unit 3 is provided with a paper discharge tray 7 that closes the paper discharge port when not in use. The paper feed unit 4 is provided with a paper feed tray 8 that holds cut paper (not shown). The ink jet printer 1 may have a paper feed structure that can print not only on a single sheet of paper S such as cut paper but also on a continuous medium such as roll paper.

  As shown in FIG. 2, the ink jet printer 1 includes a paper transport unit 10, an ink discharge unit 20, a cleaning unit 30, a carriage unit 40, a measuring instrument group 50, a control unit 60, and the like. It has.

  The paper transport unit 10 sends the paper S to a printable position, and moves the paper S by a predetermined movement amount in a predetermined direction (a direction perpendicular to the paper surface in FIG. 2 (hereinafter referred to as a paper transport direction)) during printing. It is for making it happen. That is, the paper transport unit 10 functions as a transport mechanism that transports the paper S. As shown in FIG. 4, the paper transport unit 10 includes a paper insertion slot 11A and a roll paper insertion slot 11B, a paper feed motor (not shown), a paper feed roller 13, a platen 14, a paper transport motor (hereinafter referred to as “paper feed motor”). (PF motor) 15, paper transport motor driver (hereinafter referred to as PF motor driver) 16, transport roller 17 A, paper discharge roller 17 B, free roller 18 A, and free roller 18 B. However, in order for the paper transport unit 10 to function as a transport mechanism, all of these components are not necessarily required.

  The paper insertion slot 11A is where the paper S is inserted. The paper feed motor (not shown) is a motor that transports the paper S inserted into the paper insertion slot 11A into the printer 1, and is constituted by a pulse motor. The paper feed roller 13 is a roller that automatically transports the paper S inserted into the paper insertion slot 11 into the printer 1, and is driven by the paper feed motor 12. The paper feed roller 13 has a substantially D-shaped cross section. Since the circumferential length of the circumferential portion of the feed roller 13 is set to be longer than the conveyance distance to the PF motor 15, the sheet S can be conveyed to the PF motor 15 using this circumferential portion. A plurality of media are prevented from being fed at a time by the rotational driving force of the feed roller 13 and the frictional resistance of a separation pad (not shown).

  The platen 14 is a support member that supports the paper S during printing. As shown in FIGS. 2 and 3, the PF motor 15 is a motor that feeds the paper S in the paper transport direction, and is configured by a DC motor. The PF motor driver 16 is for driving the PF motor 15. The transport roller 17 </ b> A is a roller that feeds the paper S transported into the printer by the paper feed roller 13 to a printable area, and is driven by the PF motor 15. The free roller 18A (see FIG. 4) is provided at a position facing the transport roller 17A, and presses the paper S toward the transport roller 17A by sandwiching the paper S with the transport roller 17A.

  The paper discharge roller 17B (see FIG. 4) is a roller that discharges the printed paper S to the outside of the printer. The paper discharge roller 17B is driven by the PF motor 15 by a gear (not shown). The free roller 18B is provided at a position facing the paper discharge roller 17B, and presses the paper S toward the paper discharge roller 17B by sandwiching the paper S between the paper discharge roller 17B.

  The ink discharge unit 20 is for discharging ink onto the paper S. The ink discharge unit 20 includes a discharge head 21 and a head driver 22 as shown in FIG. The ejection head 21 has a plurality of nozzles as liquid ejection units, and ejects ink droplets intermittently from each nozzle. The head driver 22 is for driving the ejection head 21 to intermittently eject ink droplets from the ejection head 21.

  As shown in FIG. 3, the cleaning unit 30 is for preventing clogging of the nozzles of the ejection head 21. The cleaning unit 30 includes a pump device 31 and a capping device 35. The pump device 31 sucks out ink from the nozzles to prevent clogging of the nozzles, and includes a pump motor 32 and a pump motor driver 33. The pump motor 32 sucks ink from the nozzles of the ejection head 21. The pump motor driver 33 drives the pump motor 32. The capping device 35 seals the nozzles of the ejection head 21 during standby, when printing is not performed, in order to prevent clogging of the nozzles of the ejection head 21.

  As shown in FIGS. 2 and 3, the carriage unit 40 is for moving the ejection head 21 in a predetermined direction (the left-right direction on the paper surface in FIG. 2 (hereinafter referred to as a carriage movement direction)). The carriage movement direction is orthogonal to the paper transport direction.

  The carriage unit 40 includes a carriage 41, a carriage motor (hereinafter referred to as a CR motor) 42, a carriage motor driver (hereinafter referred to as a CR motor driver) 43, a pulley 44, a timing belt 45, and a guide rail 46. . The carriage 41 is movable in the carriage movement direction, and fixes the ejection head 21. Accordingly, the nozzles of the ejection head 21 intermittently eject ink while moving along the carriage movement direction. Further, the carriage 41 detachably holds ink cartridges 48 and 49 that contain ink. The CR motor 42 is a motor that moves the carriage 41 in the carriage movement direction, and is constituted by a DC motor. The CR motor driver 43 is for driving the CR motor 42. The pulley 44 is attached to the rotating shaft of the CR motor 42. The timing belt 45 is driven by a pulley 44. The guide rail 46 guides the carriage 41 in the carriage movement direction.

  The measuring instrument group 50 includes a linear encoder 51, a rotary encoder 52, a paper detection sensor 53, and a paper width sensor 54. The linear encoder 51 is for detecting the position of the carriage 41. The rotary encoder 52 is for detecting the rotation amount of the transport roller 17A. The paper detection sensor 53 is for detecting the position of the leading edge of the paper S to be printed.

  As shown in FIG. 4, the paper detection sensor 53 is provided at a position where the position of the leading edge of the paper S can be detected while the paper feed roller 13 is transporting the paper S toward the transport roller 17A. The paper detection sensor 53 is a mechanical sensor that detects the leading edge of the paper S by a mechanical mechanism. More specifically, the paper detection sensor 53 has a lever that can rotate in the paper transport direction, and this lever is disposed so as to protrude into the transport path of the paper S. Therefore, the leading edge of the paper S comes into contact with the lever, and the lever is rotated, so that the paper detection sensor 53 detects the position of the leading edge of the paper S by detecting the movement of the lever. The paper width sensor 54 is attached to the carriage 41. The paper width sensor 54 is an optical sensor having a light emitting unit 541 and a light receiving unit 543, and detects the presence or absence of the paper S at the position of the paper width sensor 54 by detecting light reflected by the paper S. The paper width sensor 54 detects the position of the edge of the paper S while being moved by the carriage 41 and detects the width of the paper S. Further, the paper width sensor 54 can detect the leading edge of the paper S based on the position of the carriage 41. Since the paper width sensor 54 is an optical sensor, the position detection accuracy is higher than that of the paper detection sensor 53.

  The control unit 60 is for controlling the printer. As shown in FIG. 2, the control unit 60 includes a CPU 61, a timer 62, an interface unit 63, an ASIC 64, a memory 65, and a DC controller 66. The CPU 61 controls the entire printer, and gives control commands to the DC controller 66, the PF motor driver 16, the CR motor driver 43, the pump motor driver 32, and the head driver 22. The timer 62 periodically generates an interrupt signal for the CPU 61. The interface unit 63 transmits / receives data to / from a host computer 67 provided outside the printer. The ASIC 64 controls the printing resolution, the ejection head drive waveform, and the like based on print information sent from the host computer 67 via the interface unit 63. The memory 65 is for securing an area for storing the programs of the ASIC 64 and the CPU 61, a work area, and the like, and has storage means such as a RAM and an EEPROM. The DC controller 66 controls the PF motor driver 16 and the CR motor driver 43 based on the control command sent from the CPU 61 and the output from the measuring instrument group 50.

  In such an ink jet printer 1, during printing, the paper S is intermittently transported by a predetermined transport amount by the transport roller 17 </ b> A, and the carriage 41 is transported in the transport direction by the transport roller 17 </ b> A during the intermittent transport. Ink droplets are ejected from the ejection head 21 toward the paper S while moving in a direction orthogonal to the direction, that is, the carriage movement direction. The ejected ink droplets form dots on the paper S, and a large number of the dots are formed to form a macroscopic image on the paper S.

=== Discharge Head ===
<Nozzle arrangement in ejection head>
FIG. 5 is a diagram showing an array of ink droplet ejection nozzles provided on the lower surface of the ejection head 21. As shown in the figure, nozzle rows 211 are provided on the lower surface of the ejection head 21 for each of black (K), cyan (C), magenta (M), and yellow (Y) colors.

Each nozzle row 211 includes a plurality of nozzles # 1 to #n. The plurality of nozzles # 1 to #n are arranged on a straight line along the transport direction of the paper S at regular intervals (nozzle pitch: k · D). Here, D is a minimum dot pitch in the transport direction (that is, an interval at the highest resolution of dots formed on the paper S). K is an integer of 1 or more. It should be noted that the nozzles in each nozzle row are assigned a lower number for the nozzles on the downstream side (# 1 to #n). In addition, the nozzle rows 211 are arranged in parallel to each other at intervals along the carriage movement direction that is the movement direction of the ejection head 21.
Each nozzle # 1 to #n is provided with a piezo element (not shown) as a drive element for ejecting ink droplets. When a voltage having a predetermined time width is applied between the electrodes provided at both ends of the piezoelectric element, the piezoelectric element expands according to the voltage application time and deforms the side wall of the ink flow path. As a result, the volume of the ink flow path contracts in accordance with the expansion and contraction of the piezo element, and the ink corresponding to the contraction is ejected from the nozzles # 1 to #n of the respective colors as ink droplets.

<Driving of nozzles # 1 to #n of the ejection head>
FIG. 6 shows a block diagram of a drive signal generator 200 for driving the nozzles # 1 to #n of the ejection head 21. As shown in FIG. FIG. 7 is a timing chart of the original signal ODRV, the print signal PRT (i), and the drive signal DRV (i) showing the operation of the drive signal generator 200.

The drive signal generator 200 is provided for each of the four nozzle rows in the head driver 22 shown in FIG. The drive signal generation unit 200 includes a plurality of mask circuits 222, an original drive signal generation unit 221, and a drive signal correction unit 223, as shown in FIG. The mask circuit 222 is provided corresponding to a plurality of piezo elements for driving the nozzles # 1 to #n of the ejection head 21, respectively. In FIG. 6, the number in parentheses at the end of each signal name indicates the number of the nozzle to which the signal is supplied.
The original drive signal generator 221 generates an original drive signal ODRV that is commonly used for the nozzles # 1 to #n. The original drive signal ODRV is a signal including two pulses, a first pulse W1 and a second pulse W2, within the main scanning period for one pixel.
The drive signal correction unit 223 performs correction by shifting the timing of the drive signal waveform shaped by the mask circuit 222 back and forth in the entire return path. By correcting the timing of the drive signal waveform, the deviation of the ink droplet landing position in the forward path and the backward path is corrected, that is, the deviation of the dot formation position in the forward path and the backward path is corrected.

  As shown in FIG. 6, the input print signal PRT (i) is input to the mask circuit 222 together with the original drive signal ODRV output from the original drive signal generator 221. The print signal PRT (i) is a 2-bit serial signal per pixel, and each bit corresponds to the first pulse W1 and the second pulse W2. The mask circuit 222 is a gate for masking the original drive signal ODRV according to the level of the print signal PRT (i). That is, when the print signal PRT (i) is 1 level, the mask circuit 222 passes the corresponding pulse of the original drive signal ODRV as it is and supplies it to the piezo element as the drive signal DRV, while the print signal PRT (i) When the level is 0, the corresponding pulse of the original drive signal ODRV is cut off.

  As shown in FIG. 7, the original drive signal ODRV sequentially generates a first pulse W1 and a second pulse W2 in each pixel period T1, T2, T3, T4. Note that the pixel section means a period during which one pixel is scanned. As shown in the figure, when the print signal PRT (i) corresponds to the 2-bit pixel data “1, 0”, only the first pulse W1 is output in the first half of one pixel section. As a result, one small ink droplet (small ink droplet) is ejected from the nozzle, and a small dot (small dot) is formed on the paper S. When the print signal PRT (i) corresponds to 2-bit pixel data “0, 1”, only the second pulse W2 is output in the second half of one pixel interval. As a result, one medium-sized ink droplet (medium ink droplet) is ejected from the nozzle, and a medium-sized dot (medium dot) is formed on the paper S. When the print signal PRT (i) corresponds to 2-bit pixel data “1, 1”, the first pulse W1 and the second pulse W2 are output in one pixel section. As a result, both small ink droplets and medium ink droplets are ejected one by one from the nozzle, and a large dot (large dot) is formed on the paper S. When the print signal PRT (i) corresponds to the 2-bit pixel data “0, 0”, neither the first pulse W1 nor the second pulse W2 is output in one pixel section. In this case, no ink droplets are ejected from the nozzles, and no dots are formed on the paper S.

  As described above, the drive signal DRV (i) in one pixel section is shaped to have four different waveforms according to the four different values of the print signal PRT (i). One of these waveforms does not eject ink droplets and does not form dots, and the remaining three waveforms set the ink droplet size to two levels, small and medium. By ejecting these ink droplets alone or in combination, dots of three sizes, small, medium and large, are formed.

=== Host processing ===
FIG. 8 is a diagram for schematically explaining the processing of the host 67. As shown in the figure, the host 67 includes a computer main body 90 connected to the printer 1 and a display device 93. A computer program 96 called a “printer driver” that controls the operation of the printer 1 is installed in the computer main body 90. As shown in the figure, the printer driver 96 has an application program 95 operating under a predetermined operating system installed in the host 67. A video driver 91 and a printer driver 96 are incorporated in the operating system, and print data PD for transfer to the inkjet printer 1 is output from the application program 95 via these drivers. The application program 95 that performs image retouching or the like performs desired processing on the image to be processed, and displays the image on the display device 93 via the video driver 91.

  When the application program 95 issues a print command, the printer driver 96 of the computer main body 90 receives image data from the application program 95 and converts it into print data PD to be supplied to the inkjet printer 1. The printer driver 96 includes a resolution conversion module 97, a color conversion module 98, a halftone module 99, a replacement processing module (thinning processing module) 100, a rasterizer 101, a user interface display module 102, and a UI printer. An interface module 103 and a color conversion lookup table LUT are provided.

The resolution conversion module 97 plays a role of converting the resolution of the color image data formed by the application program 95 into a printing resolution that is a mechanical resolution of the printer 1. For example, when the resolution of the color image data does not match the printing resolution of the printer 1, the number of pixels of the color image data is reduced to reduce the number thereof, or conversely, the number of pixels is increased by interpolation. The resolution of the image data is matched with the printing resolution of the printer 1.
The image data thus converted in resolution is still image information composed of three color components of RGB. This RGB image data has, for each pixel, for example, 256 gradation values corresponding to each density for each color of RGB.

  The color conversion module 98 converts the RGB image data into CMYK ink multi-tone data usable by the printer 1 for each pixel while referring to the color conversion lookup table LUT. FIG. 9 shows a conceptual diagram of the color conversion lookup table LUT. This lookup table LUT is a three-dimensional numerical table in which each gradation value of R, G, B is associated with three coordinate axes. The value of takes a value from 0 to 255. Each of the 256 × 256 × 256 grid points GP included in the numerical table stores CMYK gradation values corresponding to the RGB gradation values of the coordinate values. Therefore, by referring to the coordinates corresponding to the RGB gradation values of each pixel, the corresponding CMYK gradation values can be obtained immediately. The multi-tone data of CMYK obtained in this way has, for example, 256 tone values for each color of CMYK.

  The halftone module 99 performs so-called halftone processing on the CMYK multi-gradation data, thereby generating halftone image data expressed with a small number of gradations that can be expressed by a printer. . That is, in the ink jet printer, the density of the color is expressed by adjusting the size and number of dots formed on the paper S. Therefore, it is necessary to convert CMYK multi-gradation data having 256 gradations for each color into image data that can be expressed by the size and number of dots of that color, and the process of performing such conversion is half-way. Tone processing.

  FIG. 10 is a conceptual diagram of a printing area A for explaining halftone processing. A part of FIG. 10 is an enlarged view showing a state where dots are formed on the paper S based on the halftone image data. ing. In this halftone process, for example, as shown in FIG. 10, the image of the print area A is divided into predetermined areas Af composed of a plurality of parts capable of forming pixels, and the density of each predetermined area Af is set. This is expressed by whether small dots, medium dots, or large dots are formed in a plurality of portions constituting the predetermined area Af.

  Here, the dot conversion graph shown in FIG. 11 is used to determine the proportion of small, medium and large dots formed in each of the predetermined areas Af. This dot conversion graph is prepared for each of the four colors CMYK. The horizontal axis of each graph is associated with the gradation value of each color, and the vertical axis is associated with the number of dots required to express the gradation value with dots. Note that the gradation value of the density of the predetermined area Af is determined based on the gradation value of the pixels in the predetermined area Af.

For each predetermined area Af to be processed, the number of dots corresponding to the gradation value of the density is read for each dot size. Then, as shown in the enlarged view of FIG. 10, the halftone image data is generated by assigning the dots for the number of read dots to the pixels in the predetermined area Af. For example, as shown in FIG. 11, if the cyan gradation value of a predetermined area Af of CMYK multi-gradation data is G1, the predetermined area Af includes n1 small dots and n2 medium dots. By assigning the pixels to the pixels, the gradation values of the multi-gradation data are reproduced when viewed macroscopically.
Halftone image data is generated from CMYK multi-gradation data by performing such conversion from gradation values to dots for the remaining magenta, yellow, and black.

The replacement processing module (thinning-out processing module) 100 performs replacement processing (thinning-out processing) on the halftone image data formed in this way. The replacement process (thinning-out process) will be described in detail later.
The rasterizer 101 rearranges the halftone image data that has been subjected to the replacement process (thinning-out process) in the order to be transferred to the printer 1, and outputs the data to the printer 1 as final print data PD. The print data PD includes raster data indicating the dot formation state during each scan and data indicating the sub-scan feed amount.

The user interface display module 102 has a function of displaying various user interface windows related to printing and a function of receiving user input in these windows.
The UI printer interface module 103 has a function of taking an interface between the user interface (UI) and the printer 1. The command instructed by the user through the user interface is interpreted and various commands COM are transmitted to the printer 1. Conversely, the command COM received from the printer 1 is interpreted and various displays are performed on the user interface.

The printer driver 96 realizes a function of transmitting / receiving various commands COM, a function of supplying print data PD to the printer 1, and the like. A program for realizing the function of the printer driver 96 is supplied in a form recorded on a computer-readable recording medium. Examples of such a recording medium include a flexible disk, CD-ROM, magneto-optical disk, IC card, ROM cartridge, punch card, printed matter on which a code such as a barcode is printed, an internal storage device of the host 67 (RAM, ROM, etc. Various media that can be read by the host 67 such as an external storage device and the like. It is also possible to download such a computer program to the computer main body 90 via the Internet.
The “liquid ejecting apparatus” means the printer 1 in a narrow sense, but means a system of the printer 1 and the computer main body 90 in a broad sense.

=== Borderless printing ===
Here, “borderless printing” will be described. “Borderless printing” is a printing method in which no margin is formed at the edge of the printing paper S. In the inkjet printer 1 according to the present embodiment, either “marginless printing” or “normal printing” can be selectively executed by selecting a printing mode.

In “normal printing”, printing is performed so that the printing area A, which is an area where ink droplets are ejected, fits on the paper S. FIG. 12 shows the relationship between the size of the print area A and the paper S at the time of “normal printing”. The print area A is set so as to be within the paper S, and the upper and lower edges and the left and right side edges of the paper S A margin is formed in the part.
When “normal print mode” is set as the print mode to perform this “normal print”, the printer driver 96 makes the print area A fit on the paper S based on the image data given from the application program. The print data PD is generated. For example, when processing image data in which the print area A cannot be stored in the paper S, a part of the image represented by the image data is excluded from the print target, or the image is reduced. It fits on the paper S.

  FIG. 13 shows the relationship between the size of the print area A and the paper S at the time of “borderless printing”. The area that protrudes from the upper and lower edges and the left and right edges of the paper S (hereinafter referred to as the discard area Aa). The printing area A is set, and ink droplets are also ejected to this area. As a result, even if the paper S is slightly misaligned with respect to the ejection head 21 due to positioning accuracy at the time of paper conveyance, the ink droplets are reliably ejected toward the edge of the paper S to form dots. In this way, no margin is formed at the end. Note that this “borderless printing” does not necessarily have to be performed on all of the upper and lower edges and the left and right edges of the paper S, as shown in FIG. May only be implemented.

  When the “marginless printing mode” is set as the printing mode to perform this “marginless printing”, the printer driver 96 causes the printing area A to protrude from the paper S by a predetermined width based on the image data. Print data PD is generated. For example, when processing image data such that the print area A becomes smaller than the paper S, the image is enlarged so that the print area A extends over the entire paper S and protrudes by the predetermined width. On the other hand, when processing image data in which the printing area A protrudes greatly from the paper S, the image is reduced so that the protrusion margin from the paper S becomes the predetermined width. Note that if the aspect ratio of the image changes from the original image and is distorted when the enlargement / reduction adjustment is performed to ensure the predetermined width, a part of the image is removed from the print target after the enlargement / reduction adjustment. The predetermined width may be secured while maintaining the aspect ratio.

The enlargement / reduction adjustment will be described in detail. The printer driver 96 stores an area having the same size as the standard size of the paper S in the memory 65 as a reference area As. Then, with reference to the reference area As, the image data is enlarged or reduced to a size that protrudes outward by the predetermined width with respect to the carriage movement direction and the conveyance direction, and the print data PD is generated. This predetermined width portion is an area determined to be detached from the paper S, and is a discarding area Aa where ink droplets are discarded.
The reference area As and the predetermined width are stored in the memory 65 for each paper size such as a postcard size and A4 size, and are read out based on the paper size information input by the user. Provided for adjustment.
Incidentally, when the paper is accurately conveyed and the paper S is properly positioned at a predetermined design position, the reference area As and the paper S coincide with each other and an image of the reference area As is printed on the paper S. Is done. However, when the position is shifted from the design position, an image of the discard area Aa is printed on the edge of the paper S.

<Processing of discarded ink>
In “marginless printing”, ink droplets that come off the paper S and are discarded without landing may adhere to the platen 14 and contaminate it. For this reason, the platen 14 of the printer 1 according to the present embodiment includes an ink recovery unit 80 for recovering ink droplets that have come off the paper S.

  FIG. 14 is a plan view of the ink collection unit 80. The ink recovery unit 80 is roughly divided into a first ink recovery unit 82 shown in the cross-sectional view of FIG. 15 and a second ink recovery unit 83 shown in the cross-sectional view of FIG. The first ink collection unit 82 is used when borderless printing is performed on the upper and lower edges of the paper S, and the second ink collection unit 83 is used when borderless printing is performed on the left and right side edges of the paper S. .

  As shown in FIGS. 14 to 16, both the first and second ink recovery portions 82 and 83 are formed as grooves having a concave cross section on the platen 14. An absorbing material 84 such as a sponge that absorbs ink droplets is provided in the groove. The discarded ink droplet reaches the absorber 84 and is absorbed by the absorber 84.

  The groove portion of the first ink recovery portion 82 shown in FIGS. 14 and 15 is provided in a straight line along the movement direction of the carriage 41, and the position of the groove portion in the transport direction is a substantially central portion of the ejection head 21. In other words, it faces nozzles #k to # k + 4. Therefore, in the case of borderless printing at the upper end as shown in FIG. 15A, ink droplets are ejected from only the nozzles #k to # k + 4 before the upper end of the paper S reaches the first ink recovery unit 82. To do. On the other hand, in the case of borderless printing at the lower end, as shown in FIG. 15B, ink droplets from only the nozzles #k to # k + 4 even after the lower end of the sheet S passes over the first ink recovery unit 82. Is discharged. The ink droplets that have not landed on the paper S among the ink droplets ejected from the nozzles #k to # k + 4 during the printing of the upper end portion and the lower end portion are the absorbents 84 of the first ink recovery portion 82. Therefore, these discarded ink droplets are effectively prevented from soiling the upper surface of the platen 14.

  14 and 16 are provided at positions facing the left and right side edges of the paper S, both of which are along the transport direction of the paper S. It is formed in a straight line. Then, in the case of borderless printing on the left and right side edge portions, in the movement of the carriage 41, ink droplets are not ejected from the nozzles only when the portion of the printing paper S is moved, but the side Ink droplets are also ejected while moving in the discarding area Aa outside the edge. Here, since the ink droplets ejected in the discarding area Aa land on the absorbing material 84 of the second ink recovery unit 83, it is effectively prevented that the platen 14 is soiled by the discarded ink droplets. .

=== Regarding Processing to Reduce Ink Drops at Borderless Printing ===
As described above, in order to perform “marginless printing”, it is necessary to set a discard area, but most of the ink droplets ejected toward the discard area do not contribute to image formation and are wasted. Therefore, it is desirable that the number of ink droplets is as small as possible. In the first place, the discarded ink droplets are ejected for the purpose of preventing a margin from being formed at the end portion of the paper S. Considering this point, the margin is visually recognized as a margin at the end portion of the paper S. It is considered preferable to reduce the ink droplets to such an extent that such missing portions of the image are not formed, that is, not so noticeable. Therefore, in the present embodiment, the ink droplets to be ejected toward the discarding area, which is an area determined to be detached from the paper S, are ejected while being reduced to an inconspicuous level.

  However, if the ink droplets in the region where there are few ink droplets to be ejected (regions where the ink density is low) are further reduced, if a misalignment occurs during paper transport, the paper in the portion where the ink droplets are reduced and ejected Printed thinly. Such a case will be described with reference to FIG. FIG. 17 is an explanatory diagram for explaining that when a positional deviation occurs during paper conveyance, the ink droplets are reduced and the ejected portion of the paper is printed thinly.

  When the ink droplets are ejected from the ejection head 21 toward the paper S, if a positional deviation occurs in the paper S, a part of the paper S is located outside the reference area As. In the example shown in FIG. 17, B1, B2, B3, and B4 are included in an ink discarding area (an area located outside the reference area As and included in the ink ejection area). Accordingly, the ink droplets ejected toward the region B1, the region B2, the region B3, and the region B4 are reduced and ejected. However, when the number of ink droplets to be ejected toward the region B1, the region B2, the region B3, and the region B4 is originally small, when the ink droplets are further reduced and ejected, the ink droplets are reduced and ejected. The area is printed thinly.

  Therefore, in the present embodiment, in order to prevent such a situation, the number of ink droplets ejected toward the discarding area to the extent that the paper is not printed thinly even when the positional deviation occurs during paper conveyance. Is reduced and discharged.

=== Method 1 of reducing the total amount of ink droplets ejected to the discard area Aa ===
A first method for reducing the total amount of ink droplets ejected to the discard area Aa will be described with reference to FIGS. FIG. 18 is an explanatory diagram for explaining a replacement process for replacing large dot data in the discard area Aa in the halftone image data with medium dot data. FIG. 19 is a flowchart of the replacement process.

  In the example shown in FIG. 18, large dots in the predetermined area Af of the discard area Aa are replaced with medium dots. If the ink weights of large dots, medium dots, and small dots are, for example, 16 ng, 8 ng, and 4 ng, respectively, the sum of the ink weights of the dots formed in the predetermined area Af before the replacement processing is as follows. Since there are 6 and 14 medium dots, it is 208 ng. Now, if the threshold value that is the criterion for determining whether or not to perform the replacement process is smaller than 208 ng, the replacement process is performed as shown in FIG. The total ink weight of the dots formed in the predetermined area Af after the replacement process is 160 ng because there are 20 medium dots. Therefore, the sum of the ink weights of the dots is reduced by 48 ng, which is equivalent to replacing all six large dots with medium dots.

Such replacement processing is performed by the replacement processing module 100 on the halftone image data before being rasterized by the rasterizer 101. The replacement processing module 100 is provided in the printer driver 96 described above, and executes the flowchart shown in FIG. Here, the replacement process will be described with reference to FIG. In step S101, the printer driver 96 determines whether the sum of the ink weights of the dots formed in the discard area Aa is larger than the threshold value. If it is determined in step S101 that the sum of the ink weights of the dots formed in the discard area Aa is greater than the threshold, the process proceeds to step S102. In step S102, the replacement processing module 100 replaces large dot data formed in the discard area Aa with medium dot data. After the process of step S102 is completed, or when it is determined in step S101 that the sum of the ink weights of the dots formed in the discard area Aa is smaller than the threshold value, the replacement process ends.
When the replacement process is executed, the halftone image data that has been subjected to the replacement process is transmitted to the rasterizer 101.
Note that the replacement process described above is executed for all of the discard areas Aa.

  In this way, only when the sum of the ink weights of the dots formed in the discard area Aa is larger than the threshold value, the replacement process for replacing the large dot data with the medium dot data is executed, and the dot area Aa is formed. When the sum of the ink weights of the dots is smaller than the threshold value, the replacement process is not executed. Therefore, the ink droplets in the region where there are few ink droplets to be ejected (region with a low ink density) are not further reduced. Therefore, when a positional deviation occurs during paper conveyance, the portion of the paper ejected with the ink droplets reduced is not printed thinly.

  In the halftone process described above, halftone image data consisting of small, medium, and large dots is once generated over the entire surface of the print area A without distinguishing the reference area As and the discard area Aa, and thereafter Thus, the large dot data in the discard area Aa in the halftone image data is mechanically replaced with medium dot data. Therefore, there is no need to prepare dot conversion graphs used for halftone processing for both the reference area As and the discard area Aa and refer to the dot conversion graph corresponding to the predetermined area to be processed one by one. The processing speed can be improved.

  Note that the timing for performing the replacement process is not limited to immediately after the halftone process, but may be after the rasterizer 101 converts the raster data.

=== Method 2 for reducing the total amount of ink droplets ejected to the discarding area Aa 2 ===
Next, a second method for reducing the total amount of ink droplets ejected to the discard area Aa will be described with reference to FIGS. 20A, 20B, 20C, and 21. FIG. FIG. 20A is a first explanatory diagram for explaining the process of thinning out dots in the discard area Aa in the halftone image data. FIG. 20B is a second explanatory diagram for explaining the process of thinning out dots in the discard area Aa in the halftone image data. FIG. 20C is a third explanatory diagram for explaining the process of thinning out dots in the discard area Aa in the halftone image data. FIG. 21 is a flowchart of the thinning process.

  In the example shown in FIG. 20A, the dot data in the discard area Aa in the halftone image data is formed as shown in the left figure of FIG. 20A. If the ink weights of large dots, medium dots, and small dots are 16 ng, 8 ng, and 4 ng, respectively, the total ink weight of the dots shown in the left figure of FIG. 20A is 9 large dots and medium dots. Since there are 10 and 9 small dots, 260 ng. Now, suppose that the threshold serving as a criterion for determining whether or not the process of reducing the total amount of dot data of ink droplets is performed is 210 ng. In this case, since the sum of the ink weights of the dots shown in the left diagram of FIG. 20A is 260 ng and larger than the threshold value 210 ng, processing for reducing the total amount of dot data is performed. When processing for reducing the total amount of dot data (in this case, thinning-out processing) is executed, the dot data is as shown in the right diagram of FIG. 20A.

Next, how dots are thinned out from the state shown in the left figure of FIG. 20A to the state shown in the right figure of FIG. 20A will be described. In the state shown in the left diagram of FIG. 20A, first, processing is performed in which dot data is thinned out in the direction intersecting the raster line (the direction in which the paper S is conveyed) from the end of the raster line. Now, the pixels in the raster line direction of the discard area Aa are numbered as n (n = 1, 2,..., 7) in order from the edge of the paper S. The pixels in the discard area Aa are represented by (raster line direction number, raster line number (conveyance direction number)). For example, in the left diagram of FIG. 20A, large dot data is formed in the pixel (1, 1). Now, the sum of the ink weights of the dots shown in the left diagram of FIG. 20A is 260 ng. Since the threshold value serving as a reference for determining whether or not the process of thinning out dot data is performed is 210 ng, the thinning process is executed. In this case, first, the thinning-out process is executed from the dots formed in the pixels (7, n (n = 1, 2,..., 7)).
In the example shown in the left diagram of FIG. 20A, first, small dots formed in the pixel (7, 2) are thinned out. Since the ink weight of the small dots is 4 ng, the sum of the ink weights of the dots is 256 ng. Therefore, since the threshold value serving as a reference for determining whether or not the process of thinning out dot data is performed is 210 ng, the thinning process is further continued. Next, the small dots formed in the pixel (7, 4) are thinned out, and the total ink weight of the dots is 252 ng. Next, the medium dots formed in the pixels (7, 6) are thinned out, and the total ink weight of the dots is 244 ng. Even after the dot data formed in the pixels of (7, n (n = 1, 2,..., 7)) are thinned out, the sum of the ink weights of the dots is larger than the threshold value. Therefore, next, the thinning-out process of dots formed in the pixel of (6, n (n = 1, 2,..., 7)) is executed. First, large dots formed in the pixel (6, 1) are thinned out, and the total ink weight of the dots is 228 ng. Then, the small dots formed on the pixel (6, 3) are thinned out, and the total ink weight of the dots is 224 ng. Then, the medium dots formed in the pixel (6, 4) are thinned out, and the total ink weight of the dots is 216 ng. The large dots formed in the pixels (6, 5) are thinned out, and the total ink weight of the dots is 200 ng. At this time, the sum of the ink weights of the dots is smaller than the threshold value 210 ng which is a criterion for determining whether or not the thinning process is performed, and thus the thinning process is completed. After the thinning process is completed, dots are formed as shown in the right figure of FIG. 20A.

  Next, a dot thinning process different from the method shown in FIG. 20A will be described with reference to FIG. 20B. FIG. 20B is a second explanatory diagram for explaining the process of thinning out dots in the discard area Aa in the halftone image data.

  In the example shown in FIG. 20B, the dot data in the discard area Aa in the halftone image data is formed as shown in the left figure of FIG. 20B. The dot data shown in the left diagram of FIG. 20B is the same as the dot data shown in the left diagram of FIG. 20A. As in the case of FIG. 20A, assuming that the ink weights of large dots, medium dots, and small dots are 16 ng, 8 ng, and 4 ng, respectively, the sum of the ink weights of the dots shown in the left diagram of FIG. Since there are 9 dots, 10 medium dots, and 9 small dots, it is 260 ng. Now, suppose that the threshold serving as a criterion for determining whether or not the process of reducing the total amount of dot data of ink droplets is performed is 210 ng. In this case, since the sum of the dot data shown in the left diagram of FIG. 20B is 260 ng and larger than the threshold value 210 ng, a process of reducing the total amount of dot data is performed. When processing for reducing the total amount of dot data (in this case, thinning processing) is executed, the dot data is as shown in the right diagram of FIG. 20B.

Next, how dots are thinned out from the state shown in the left diagram of FIG. 20B to the state shown in the right diagram of FIG. 20B will be described. In the state shown in the left diagram of FIG. 20B, first, the dot data is thinned out in order from the even-numbered raster line in the direction intersecting the raster line (the direction in which the paper S is conveyed) from the end of the raster line. Is executed. Now, the pixels in the raster line direction of the discard area Aa are numbered as n (n = 1, 2,..., 7) in order from the edge of the paper S. The pixels in the discard area Aa are represented by (raster line direction number, raster line number (conveyance direction number)). For example, in the left diagram of FIG. 20B, large dot data is formed in the pixel (1, 1). Now, the total ink weight of the dots shown in the left diagram of FIG. 20B is 260 ng. Since the threshold value serving as a reference for determining whether or not the process of thinning out dot data is performed is 210 ng, the thinning process is executed. In this case, first, the thinning-out process is executed from the dots formed in the pixel of (7, n (n = 2, 4, 6)).
In the example shown in the left diagram of FIG. 20B, first, small dots formed in the pixel (7, 2) are thinned out. Since the ink weight of the small dots is 4 ng, the sum of the ink weights of the dots is 256 ng. Therefore, since the threshold value serving as a reference for determining whether or not the process of thinning out dot data is performed is 210 ng, the thinning process is further continued. Next, the small dots formed in the pixel (7, 4) are thinned out, and the total ink weight of the dots is 252 ng. Next, the medium dots formed in the pixel (7, 6) are thinned out, and the total ink weight of the dots is 244 ng. Even after the dot data formed in the pixels of (7, n (n = 2, 4, 6)) are thinned out, the sum of the ink weights of the dots is larger than the threshold value. Therefore, next, the thinning-out process of dots formed in the (6, n (n = 2, 4, 6)) pixel is executed. First, the medium dots formed in the pixel (6, 4) are thinned out, and the total ink weight of the dots is 236 ng. Even after the dot data formed in the (6, n (n = 2, 4, 6)) pixels are thinned out, the sum of the ink weights of the dots is larger than the threshold value. Therefore, next, the thinning-out process of dots formed in the pixel of (5, n (n = 2, 4, 6)) is executed. First, the medium dots formed in the pixel (5, 2) are thinned out, and the total ink weight of the dots is 228 ng. Then, the small dots formed on the pixel (5, 4) are thinned out, and the total ink weight of the dots is 224 ng. The large dots formed on the (5, 6) pixels are thinned out, and the total ink weight of the dots is 208 ng. At this time, the sum of the ink weights of the dots is smaller than the threshold value 210 ng which is a criterion for determining whether or not the thinning process is performed, and thus the thinning process is completed. After the thinning process is completed, dots are formed as shown in the right figure of FIG. 20B.

  In the example shown in FIGS. 20A and 20B, processing is performed in which dot data is thinned out in the direction intersecting the raster line (the direction in which the paper S is conveyed) from the end of the raster line. Therefore, the rate of thinning out dot data increases toward the end in the raster line direction. In this way, the reason for increasing the rate of thinning out dot data toward the end in the raster line direction is that the probability that ink droplets land on the paper S decreases toward the end in the raster line direction. This is because the ink droplets ejected toward the vicinity of the end portion are less likely to be manifested as a missing portion of the image when the positional deviation occurs during the conveyance of the paper. Accordingly, it is possible to increase the number of ink droplets that can be reduced as much as possible while suppressing deterioration in image quality due to thinning.

  Next, with reference to FIG. 20C, a dot thinning process different from the method shown in FIGS. 20A and 20B will be described. FIG. 20C is a third explanatory diagram for explaining the process of thinning out dots in the discard area Aa in the halftone image data.

  In the example shown in FIG. 20C, the dot data in the discard area Aa in the halftone image data is formed as shown in the left figure of FIG. 20C. The dot data shown in the left diagram of FIG. 20C is the same as the dot data shown in the left diagram of FIG. 20A and the left diagram of FIG. 20B. As in FIGS. 20A and 20B, assuming that the ink weights of large dots, medium dots, and small dots are 16 ng, 8 ng, and 4 ng, respectively, the ink weights of the dots shown in the left diagram of FIG. 20C Is 260 ng because there are 9 large dots, 10 medium dots, and 9 small dots. Now, suppose that the threshold serving as a criterion for determining whether or not the process of reducing the total amount of dot data of ink droplets is performed is 210 ng. In this case, since the sum of the ink weights of the dots shown in the left diagram of FIG. 20C is 260 ng and larger than the threshold value 210 ng, a process of reducing the sum of the dot data is performed. When processing for reducing the total amount of dot data (in this case, thinning-out processing) is executed, the dot data is as shown in the right diagram of FIG. 20C.

Next, how dots are thinned out from the state shown in the left figure of FIG. 20C to the state shown in the right figure of FIG. 20C will be described. In the state shown in the left diagram of FIG. 20C, a process of thinning out dot data in order from the end of the raster line is executed for each odd-numbered raster line. Now, the pixels in the raster line direction of the discard area Aa are numbered as n (n = 1, 2,..., 7) in order from the edge of the paper S. The pixels in the discard area Aa are represented by (raster line direction number, raster line number (conveyance direction number)). For example, in the left diagram of FIG. 20C, large dot data is formed in the pixel (1, 1). Now, the total ink weight of the dots shown in the left diagram of FIG. 20C is 260 ng. Since the threshold value serving as a reference for determining whether or not the process of thinning out dot data is performed is 210 ng, the thinning process is executed. In this case, first, a thinning process is executed from the dots formed in the pixels of (n (n = 7, 6,..., 3), 1).
In the example shown in the left diagram of FIG. 20C, first, large dots formed in the pixel (6, 1) are thinned out. Since the ink weight of the large dots is 16 ng, the total dot data is 244 ng. Therefore, since the threshold value serving as a reference for determining whether or not the process of thinning out dot data is performed is 210 ng, the thinning process is further continued. Next, the medium dots formed in the pixel (5, 1) are thinned out, and the total ink weight of the dots is 236 ng. Next, the small dots formed on the pixel (3, 1) are thinned out, and the total ink weight of the dots is 232 ng. Even after the dot data formed in the pixels (n (n = 7, 6,..., 3), 1) are thinned out, the sum of the ink weights of the dots is larger than the threshold value. Therefore, next, the thinning-out process of dots formed in the pixels of (n (n = 7, 6,..., 3), 3) is executed. First, small dots formed in the pixel (6, 3) are thinned out, and the total ink weight of the dots is 228 ng. Next, the medium dots formed in the (3, 3) pixels are thinned out, and the total ink weight of the dots is 220 ng. Even after the dot data formed in the pixels (n (n = 7, 6,..., 3), 3) are thinned out, the sum of the ink weights of the dots is larger than the threshold value. Therefore, next, the thinning-out process of dots formed in the pixels of (n (n = 7, 6,..., 3), 5) is executed. First, large dots formed on the pixels (6, 5) are thinned out, and the total ink weight of the dots is 204 ng. At this time, the sum of the ink weights of the dots is smaller than the threshold value 210 ng which is a criterion for determining whether or not the thinning process is performed, and thus the thinning process is completed. After the thinning process is completed, dots are formed as shown in the right figure of FIG. 20C.

In the example shown in FIG. 20C, dot data formed in pixels of raster line direction number n (n = 7, 6,..., 3) is thinned out, and raster line direction number n (n = 2). The data of dots formed in the pixel 1) is not thinned out. As described above, the reason why the dot data formed in the pixel of the number n (n = 2, 1) in the raster line direction is not thinned is that the closer to the edge of the sheet S (in the raster line direction) The smaller the number), the higher the probability that the ink droplet will land on the paper S. Therefore, if a portion of ink droplets with a high probability of ink droplets landing on the paper S is thinned out, the influence of the thinning is easily manifested as a missing portion of an image when a positional shift occurs during paper transport.
Further, in the state shown in the left diagram of FIG. 20C, the process of thinning out the dot data in order from the end of the raster line is executed for each odd-numbered raster line, but for each even-numbered raster line, A process of thinning out dot data in order from the end of the raster line may be executed.

Such thinning processing is performed by the thinning processing module 100 on the halftone image data before being rasterized by the rasterizer 101. This thinning processing module is provided in the above-described printer driver 96, and executes the flowchart shown in FIG. Here, the thinning process will be described with reference to FIG. In step S201, the printer driver 96 determines whether the sum of the ink weights of the dots formed in the discard area Aa is larger than the threshold value. If it is determined in step S201 that the sum of the ink weights of the dots formed in the discard area Aa is greater than the threshold, the process proceeds to step S202. In step S202, the thinning process module 100 executes a process of thinning out dot data formed in the discard area Aa. After the process of step S202 is completed, or when it is determined in step S201 that the sum of the ink weights of the dots formed in the discard area Aa is smaller than the threshold value, the thinning process ends.
Then, the halftone image data that has been subjected to the thinning process is transmitted to the rasterizer 101.
It should be noted that the above-described thinning-out process is executed for all of the discard areas Aa.

=== Method 3 of reducing the total amount of ink droplets ejected to the discard area Aa ===
Next, a third method for reducing the total amount of ink droplets ejected to the discard area Aa will be described with reference to FIGS. 22A and 22B. FIG. 22A is an explanatory diagram for describing processing for reducing the total amount of dots when the total amount of dots in the discard region Aa in the halftone image data is large. FIG. 22B is an explanatory diagram for describing processing for reducing the total amount of dots when the total amount of dots in the discard area Aa in the halftone image data is small.

  In the example shown in FIG. 22A, the dot data in the discard area Aa in the halftone image data is formed as shown in the left figure of FIG. 22A. If the ink weights of large dots, medium dots, and small dots are, for example, 16 ng, 8 ng, and 4 ng, respectively, the sum of the ink weights of the dots shown in the left diagram of FIG. 22A is nine large dots and medium dots. Since there are 10 and 9 small dots, 260 ng. Then, processing for reducing the total amount of dots is executed from this state. Assume that the process of reducing the total amount of dots is, for example, a process of reducing the total amount of dots by 20%. In that case, the dot data after the process of reducing the total amount of dots is executed is as shown in the right diagram of FIG. 22A. In the example shown in the right diagram of FIG. 22A, the total ink weight of the dots is 208 ng because there are 8 large dots, 6 medium dots, and 8 small dots. Therefore, in this case, the processing for reducing the total amount of dots is executed, and thus the total ink weight of the dots is reduced by 52 ng.

On the other hand, in the example shown in FIG. 22B, the dot data in the discard region Aa in the halftone image data is formed as shown in the left diagram of FIG. 22B. If the ink weights of large dots, medium dots, and small dots are 16 ng, 8 ng, and 4 ng, respectively, as in the case of the left diagram of FIG. 22A, for example, the sum of the ink weights of the dots shown in the left diagram of FIG. , 200 ng because there are 8 large dots, 6 medium dots, and 6 small dots. Then, processing for reducing the total amount of dots is executed from this state. Assume that the process of reducing the total amount of dots is, for example, a process of reducing the total amount of dots by 20%. In that case, the dot data after the process of reducing the total dot amount is executed is as shown in the right diagram of FIG. 22B. In the example shown in the right diagram of FIG. 22B, the total ink weight of the dots is 160 ng because there are seven large dots, four medium dots, and four small dots. Therefore, in this case, the processing for reducing the total amount of dots is executed, and thus the total ink weight of the dots is reduced by 40 ng.

  As described above, even if the same processing for reducing the total amount of dots by 20% is executed, the larger the total amount of dots before the processing is, the larger the ink weight of the dots to be reduced. In other words, even if the same processing for reducing the total amount of dots by 20% is executed, the ink weight of the reduced dots is smaller when the total amount of dots before the processing is smaller. That is, a large number of ink droplets are reduced in a region where ink droplets to be ejected are high (regions with high ink density), and a small amount of ink droplets are reduced in regions where ink droplets are to be ejected (regions with low ink density). .

  Therefore, the ink droplets in the region where there are few ink droplets to be ejected are not reduced by the same ink weight as the ink droplets in the region where many ink droplets are to be ejected. Therefore, it is possible to prevent a region where few ink droplets are to be ejected from being thinly printed when a positional deviation occurs during paper conveyance.

=== Other Embodiments ===
In the above, the replacement processing for replacing large dots with medium dots is performed by the replacement processing module included in the printer driver 96 for the halftone image data before being rasterized by the rasterizer 101.
However, the inkjet printer 1 can perform the above replacement process. In that case, the program executed by the replacement processing module may be stored in the memory 65. And CPU61 should just read a program from the memory 65 as needed, and should perform a replacement process.

In the above, thinning processing for thinning dots is performed by the thinning processing module provided in the printer driver 96 for halftone image data before rasterization by the rasterizer 101.
However, the ink-jet printer 1 can perform the thinning process described above. In that case, the program executed by the thinning processing module may be stored in the memory 65. And CPU61 should just read a program from the memory 65 as needed, and may perform a thinning process.

  Further, although an ink jet printer has been described as an example of the liquid ejection apparatus of the present embodiment, the above embodiment is for facilitating the understanding of the present invention, and is intended to limit the interpretation of the present invention. It is not a thing. The present invention can be changed or improved without departing from the gist thereof, and needless to say, the present invention includes equivalents thereof. In particular, even the embodiments described below are included in the liquid ejection apparatus according to the present invention.

In the present embodiment, part or all 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.
In addition to the printing paper S, the medium may be a cloth or a film.
In addition, a part of the processing performed on the liquid ejection apparatus side may be performed on the host side, and a dedicated processing apparatus is interposed between the liquid ejection apparatus and the host, and processing is performed on this processing apparatus. Some may be performed.

<About liquid ejection device>
Examples of the liquid ejection apparatus of the present invention include the above-described printing apparatuses such as an ink jet printer, and in addition to these, for example, a color filter manufacturing apparatus, a dyeing apparatus, a fine processing apparatus, a semiconductor manufacturing apparatus, a surface processing apparatus, and a three-dimensional molding apparatus. The present invention can also be applied to a machine, a liquid vaporizer, an organic EL manufacturing apparatus (particularly a polymer EL manufacturing apparatus), a display manufacturing apparatus, a film forming apparatus, a DNA chip manufacturing apparatus, and the like.

<About liquid>
The liquid of the present invention is not limited to the inks described above, such as dye inks and pigment inks. For example, metal materials, organic materials (particularly polymer materials), magnetic materials, conductive materials, wiring materials, synthetic materials, and the like. A film material, electronic ink, processing liquid, gene solution, or the like (including water) can also be applied. Moreover, about the component of a liquid, what comprises liquid, such as a solvent other than water, is included as a solvent.

<About media>
As for the medium, the paper S described above includes plain paper, matte paper, cut paper, glossy paper, roll paper, paper, photographic paper, roll type photographic paper, etc. In addition to these, OHP film, glossy film, etc. It may be a film material, a cloth material, a metal plate material, or the like. That is, any medium may be used as long as it can be a liquid discharge target.

<About nozzle row>
The nozzle rows provided in the ejection head are not limited to the above-described four rows of black (K), cyan (C), magenta (M), and yellow (Y), and eject other colors of ink. A nozzle row may be further provided. For example, a nozzle array that discharges clear ink that is transparent ink may be provided.

1 is a perspective view illustrating an embodiment of an inkjet printer. It is explanatory drawing of the whole structure of an inkjet printer. It is a figure which shows the carriage etc. of an inkjet printer. It is a figure which shows the conveyance mechanism of an inkjet printer. It is explanatory drawing which shows the arrangement | sequence of the nozzle in a discharge head. It is a block diagram of a drive signal generation part. It is a timing chart which shows operation | movement of a drive signal generation part. It is explanatory drawing for demonstrating the process by the side of a host. It is a conceptual diagram for demonstrating a color conversion lookup table. It is a key map of a printing field for explaining halftone processing. It is a conceptual diagram of the dot conversion graph provided for a halftone process. It is explanatory drawing explaining the relationship between the size of the printing area | region and paper at the time of normal printing. It is explanatory drawing explaining the relationship between the size of the printing area | region at the time of borderless printing, and a paper. It is a top view which shows an ink collection | recovery part. 15A and 15B are cross-sectional views showing the first ink recovery unit. It is sectional drawing which shows a 2nd ink collection | recovery part. FIG. 10 is an explanatory diagram for explaining that when a positional deviation occurs during paper conveyance, ink droplets are reduced and the discharged paper is printed thinly. It is explanatory drawing for demonstrating the replacement process which replaces the data of the large dot of the discard area | region Aa in halftone image data with the data of a medium dot. It is a flowchart of a replacement process. FIG. 20A is a first explanatory diagram for explaining the process of thinning out dots in the discard area Aa in the halftone image data. FIG. 20B is a second explanatory diagram for explaining the process of thinning out dots in the discard area Aa in the halftone image data. FIG. 20C is a third explanatory diagram for explaining the process of thinning out dots in the discard area Aa in the halftone image data. It is a flowchart of a thinning process. FIG. 22A is an explanatory diagram for describing processing for reducing the total amount of dots when the total amount of dots in the discard region Aa in the halftone image data is large. FIG. 22B is an explanatory diagram for describing processing for reducing the total amount of dots when the total amount of dots in the discard area Aa in the halftone image data is small.

Explanation of symbols

1 Inkjet printer, 2 operation panel, 3 paper discharge unit, 4 paper supply unit,
5 operation buttons, 6 indicator lamps, 7 paper discharge tray, 8 paper feed tray,
10 paper transport unit, 13 paper feed roller, 14 platen,
15 Paper transport motor (PF motor),
16 Paper transport motor driver (PF motor driver),
17A transport roller, 17B paper discharge roller,
18A / 18B free roller, 20 ink discharge unit,
21 discharge head, 211 nozzle row, 22 head driver,
220 drive signal generator, 221 original drive signal generator,
222 mask circuit, 223 drive signal correction unit,
30 Cleaning unit,
31 pump device, 32 pump motor, 33 pump motor driver,
35 capping device, 40 carriage unit, 41 carriage,
42 Carriage motor (CR motor),
43 Carriage motor driver (CR motor driver),
44 pulley, 45 timing belt, 46 guide rail,
50 measuring instrument group, 51 linear encoder, 511 linear scale,
512 detector, 512A light emitting diode, 512B collimator lens,
512C detection processing unit, 512D photodiode,
512E signal processing circuit, 512F comparator,
52 Rotary encoder, 53 Paper detection sensor, 54 Paper width sensor,
60 control unit, 61 CPU, 62 timer,
63 interface part, 64 ASIC, 65 memory,
66 DC controller, 67 Host computer,
80 ink collecting section, 82 first ink collecting section, 83 second ink collecting section,
84 Absorber,
90 computer body, 91 video driver, 93 display device,
95 application programs, 96 printer drivers,
97 resolution conversion module, 98 color conversion module,
99 halftone module, 100 rasterizer,
101 user interface display module,
102 UI printer interface module A print area, As reference area, Aa discard area,
Af predetermined area, S medium (paper)

Claims (18)

In a liquid ejection apparatus provided with a liquid ejection unit for ejecting liquid droplets toward the medium to form dots on the medium,
It is possible to reduce the total amount of liquid droplets to be ejected toward a predetermined region near the edge of the medium, and to eject the liquid droplets from the liquid ejection unit,
The difference between the total amount of liquid droplets to be ejected in a given area and the total amount of liquid droplets to be actually ejected is greater than the difference in other areas where the total amount of liquid droplets to be ejected is larger than that predetermined area. Is a small liquid discharge device. The liquid ejection apparatus according to claim 1,
When the total amount of liquid droplets to be ejected toward a predetermined area near the edge of the medium is larger than a predetermined threshold, the liquid ejection unit reduces the total amount of liquid droplets and moves the liquid toward the predetermined area. When the total amount of liquid droplets to be discharged toward a predetermined region near the edge of the medium is smaller than a predetermined threshold, the liquid is directed toward the predetermined region without reducing the total amount of liquid droplets. A liquid discharge apparatus for discharging droplets. The liquid ejection apparatus according to claim 1,
A liquid ejecting apparatus, wherein the liquid droplets are ejected from the liquid ejecting unit by reducing a total amount of liquid droplets to be ejected toward a predetermined region near the edge of the medium by a predetermined ratio. The liquid ejection apparatus according to claim 1, wherein:
When the liquid droplets are ejected from the liquid ejection unit toward a predetermined area near the edge of the medium, an appropriate number of liquid droplets are thinned and ejected from the liquid droplets to be ejected toward the area. A liquid discharge apparatus characterized by that. The liquid ejection apparatus according to claim 1, wherein:
When ejecting the liquid droplets from the liquid ejection unit toward a predetermined area near the edge of the medium, at least one of the liquid droplets to be ejected is changed to a smaller liquid droplet and ejected. A liquid discharge apparatus characterized by: In the liquid ejection device according to claim 4 or 5,
The predetermined area near the edge of the medium is an area that deviates from a reference area corresponding to the size of the medium, stores the reference area, and is based on image data formed in a size larger than the reference area. A liquid discharge apparatus that discharges the liquid droplets. The liquid ejection apparatus according to claim 6, wherein
The liquid ejection unit includes a nozzle that ejects the liquid droplets,
By discharging liquid droplets while moving the nozzle, a raster line in which a large number of dots are aligned on a straight line is formed,
An image formed on a medium based on the image data is configured such that the raster lines are arranged in parallel at a predetermined interval in a direction intersecting the raster line direction. The liquid ejection device according to claim 7, wherein
The liquid discharge apparatus according to claim 1, wherein a rate of reducing the liquid droplets increases toward the end in the raster line direction. The liquid ejection apparatus according to claim 8, wherein
The liquid ejecting apparatus according to claim 1, wherein the liquid droplets are reduced in a direction crossing the raster line from an extreme end in the raster line direction. The liquid ejection apparatus according to claim 8, wherein
The liquid ejecting apparatus, wherein the liquid droplets are reduced for each raster line. The liquid ejecting apparatus according to claim 1,
A support member for supporting the medium when the liquid droplets discharged from the liquid discharge unit land on the medium;
The liquid ejecting apparatus, wherein the support is formed with a recess corresponding to a region determined to be detached from the medium, and the medium is supported by the protrusion of the support member. The liquid ejection device according to any one of claims 1 to 11,
The liquid droplets are ink droplets. The liquid ejection apparatus according to any one of claims 1 to 12,
A liquid ejection apparatus that performs borderless printing on the medium. In a liquid ejection apparatus provided with a liquid ejection unit for ejecting liquid droplets toward the medium to form dots on the medium,
It is possible to reduce the total amount of liquid droplets to be ejected toward a predetermined region near the edge of the medium, and to eject the liquid droplets from the liquid ejection unit,
The difference between the total amount of liquid droplets to be ejected in a given area and the total amount of liquid droplets to be actually ejected is greater than the difference in other areas where the total amount of liquid droplets to be ejected is larger than that predetermined area. But small,
When the total amount of liquid droplets to be ejected toward a predetermined area near the edge of the medium is larger than a predetermined threshold, the liquid ejection unit reduces the total amount of liquid droplets and moves the liquid toward the predetermined area. When the total amount of liquid droplets to be discharged toward a predetermined region near the edge of the medium is smaller than a predetermined threshold, the liquid is directed toward the predetermined region without reducing the total amount of liquid droplets. Discharging drops,
When the liquid droplets are ejected from the liquid ejection unit toward a predetermined area near the edge of the medium, an appropriate number of liquid drops are thinned out and ejected from the liquid droplets to be ejected toward the area. ,
The predetermined area in the vicinity of the edge of the medium is an area that deviates from a reference area corresponding to the size of the medium, stores the reference area, and is based on image data formed in a size larger than the reference area. Discharging the liquid droplets;
The liquid ejection unit includes a nozzle that ejects the liquid droplets,
By discharging liquid droplets while moving the nozzle, a raster line in which a large number of dots are aligned on a straight line is formed,
An image formed on the medium based on the image data is configured in parallel with a predetermined interval in a direction in which the raster line intersects the raster line direction,
The rate of reducing the liquid droplets increases toward the end in the raster line direction,
Reducing the liquid drops in the direction intersecting the raster line from the extreme end of the raster line direction;
A support member for supporting the medium when the liquid droplets discharged from the liquid discharge unit land on the medium;
The support is formed with a recess corresponding to a region determined to be detached from the medium, and the medium is supported by the protrusion of the support member,
The liquid drop is an ink drop;
A liquid ejection apparatus that performs borderless printing on the medium. Reducing the total amount of liquid droplets to be ejected from the liquid ejection unit toward a predetermined region near the edge of the medium, and ejecting the liquid droplets;
The difference between the total amount of liquid droplets to be ejected in a given area and the total amount of liquid droplets to be actually ejected is greater than the difference in other areas where the total amount of liquid droplets to be ejected is larger than that predetermined area. Is a small print control device. In the printing device,
A function of reducing the total amount of liquid droplets to be discharged toward a predetermined region near the edge of the medium, and discharging the liquid droplets;
The difference between the total amount of liquid droplets to be ejected in a given area and the total amount of liquid droplets to be actually ejected is greater than the difference in other areas where the total amount of liquid droplets to be ejected is larger than that predetermined area. Is a program for realizing the function of ejecting liquid droplets so that they become smaller. In a liquid ejection method for ejecting liquid droplets toward a medium to form dots on the medium,
Reducing the total amount of liquid droplets to be ejected toward a predetermined region near the edge of the medium, ejecting the liquid droplets,
The difference between the total amount of liquid droplets to be ejected in a given area and the total amount of liquid droplets to be actually ejected is greater than the difference in other areas where the total amount of liquid droplets to be ejected is larger than that predetermined area. A liquid discharge method characterized by discharging liquid droplets so as to be small. A liquid ejection system comprising a computer main body and a liquid ejection device connectable to the computer main body,
The liquid ejection device is capable of reducing the total amount of liquid droplets to be ejected toward a predetermined area near the edge of the medium and ejecting the liquid droplets from the liquid ejection section. The difference between the total amount of liquid droplets to be ejected and the total amount of liquid droplets actually ejected is smaller than the difference in other regions where the total amount of liquid droplets to be ejected is larger than the predetermined region A liquid discharge system characterized by that.

Images