JP2004209887A - Liquid discharge device, liquid discharge method, program and computer system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high quality liquid discharge device by suppressing the generation of a striped pattern (banding) appearing on a printing sheet. <P>SOLUTION: This liquid discharge device (ink jet printer) repeats alternately a discharge action to discharge liquid (ink) through a liquid discharge part (nozzle) and a moving action to relatively move a medium (printing sheet) relative to the liquid discharge part. In the moving action, the medium is relatively moved by a moving quantity corresponding to the liquid quantity (the number of dots, for example) to be discharged to the medium. This allows the mixing condition discharged to the medium to be adjusted, while suppressing the generation of a striped pattern. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a liquid ejection device that ejects a liquid to a medium. Further, the present invention relates to a liquid discharge method, a program, and a computer system using such a liquid discharge device.
[0002]
[Prior art]
2. Related Art As a printing apparatus that prints an image on various media such as paper, cloth, and film, an inkjet printer that performs printing by discharging ink is known. In such an inkjet printer, printing is performed by alternately repeating a printing operation (ejection operation) for discharging ink from nozzles and a transport operation (moving operation) for moving a medium in a transport direction.
[0003]
[Patent Document 1]
JP 2001-71475 A
[0004]
[Problems to be solved by the invention]
In such a printing apparatus, when an image is printed on a medium, stripes (banding) may appear. This stripe is a dark stripe (also called “dark banding”, “black banding” or “dark banding”) or a light stripe (“bright banding”, “white banding” or “light banding”). Also called).
Such stripes also occur in liquid ejection devices other than ink jet printers.
[0005]
An object of the present invention is to suppress the occurrence of such stripes and provide a high-quality device.
[0006]
[Means for Solving the Problems]
A main aspect of the present invention for solving the above-mentioned problem is a liquid ejection apparatus that alternately repeats an ejection operation of ejecting liquid from a liquid ejection unit and a movement operation of moving a medium relative to the liquid ejection unit. In the moving operation, the medium is relatively moved by a moving amount corresponding to an amount of liquid to be discharged onto the medium.
Other features of the present invention will become apparent from the description of the present specification and the accompanying drawings.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
At least the following matters will be made clear by the description in this specification and the accompanying drawings. A liquid discharging apparatus that alternately repeats a discharging operation of discharging liquid from a liquid discharging unit and a moving operation of moving a medium relative to the liquid discharging unit, wherein the moving operation includes Wherein the medium is relatively moved by a movement amount corresponding to an amount of the liquid to be ejected to the liquid ejection device. According to such a liquid ejecting apparatus, it is possible to reduce the occurrence of stripes when ejecting the liquid onto the medium.
[0008]
In this liquid ejecting apparatus, it is preferable that the amount of the liquid is related to the number of dots to be formed on the medium. Since the degree of mixing of the liquid on the medium differs depending on the number of dots formed on the medium, if the moving operation is performed with a moving amount according to the number of dots, the degree of mixing of the liquid can be adjusted and the occurrence of stripes can be reduced. be able to. It is preferable that the moving amount increases as the number of dots increases. When the number of dots increases, the amount of liquid mixed on the medium increases, and stripes easily occur. Therefore, if the movement amount is increased and the dot interval is increased, the occurrence of stripes can be reduced.
[0009]
In this liquid ejecting apparatus, it is preferable that the amount of the liquid is related to the number of droplets to be ejected from the liquid ejecting unit. The degree of mixing of the liquid on the medium varies depending on the number of ejected droplets, so if the moving operation is performed with a moving amount corresponding to the number of ejected droplets, the degree of mixing of the liquid can be adjusted, and stripes are generated. Can be reduced. It is preferable that the moving amount increases as the number of the droplets increases. When the number of ejected droplets increases, the amount of liquid mixed on the medium increases and stripes easily occur. Therefore, if the movement amount is increased and the dot interval is increased, the occurrence of stripes can be reduced. .
[0010]
In this liquid ejecting apparatus, it is preferable that the amount of the liquid is related to a size of a dot to be formed on the medium. The degree of mixing of the liquid on the medium varies depending on the size of the dots formed on the medium.If the moving operation is performed with a moving amount according to the size of the dots, the degree of mixing of the liquid can be adjusted, and the occurrence of stripes can be reduced. Can be reduced. It is preferable that the larger the dots, the larger the movement amount. When the size of the dots increases, the amount of liquid mixed on the medium increases, and stripes easily occur. Therefore, if the movement amount is increased and the dot interval is increased, the occurrence of the stripes can be reduced.
[0011]
In such a liquid ejection device, the amount of the liquid is related to a size of a droplet to be ejected from the liquid ejection unit. Since the degree of mixing of the liquid on the medium differs depending on the size of the discharged droplet, if the moving operation is performed with a moving amount according to the size of the discharged droplet, the degree of mixing of the liquid can be adjusted, and the stripes can be adjusted. Can be reduced. Then, it is preferable that the larger the droplet, the larger the moving amount. When the size of the ejected droplets increases, the amount of liquid mixed on the medium increases and stripes easily occur. Therefore, if the amount of movement is increased and the dot interval is increased, the occurrence of stripes can be reduced.
[0012]
In such a liquid ejecting apparatus, the liquid ejecting apparatus includes a plurality of the liquid ejecting sections, and the medium has a moving amount corresponding to an amount of the liquid to be ejected from the plurality of liquid ejecting sections. Is relatively moved. According to such a liquid ejecting apparatus, the degree of mixing of the liquids varies depending on the total amount of the liquid ejected from the plurality of liquid ejecting sections. Can be.
[0013]
In this liquid ejecting apparatus, the liquid ejecting apparatus includes a plurality of the liquid ejecting units, and the amount of the liquid to be ejected from a part of the plurality of the liquid ejecting units. Preferably, the medium is relatively moved. Further, the plurality of liquid ejection units are arranged in a row, and the part of the liquid ejection units is the liquid ejection unit arranged at an end of the arranged plurality of liquid ejection units. Part. In addition, it is preferable that dots formed by the liquid ejection unit arranged at one end and dots formed by the liquid ejection unit arranged at the other end are adjacent to each other on the medium. Since the liquid ejected from the liquid ejection unit at the end is mixed on the medium to generate stripes, such a liquid ejection apparatus can reduce the occurrence of stripes.
[0014]
In this liquid ejecting apparatus, it is preferable that the liquid ejecting apparatus performs the ejecting operation on the medium a plurality of times, and the amount of the liquid is determined for each ejecting operation. Further, at the time of the moving operation performed between a certain discharging operation and another discharging operation, at least one of the amount of the liquid of the certain discharging operation and the amount of the liquid of the other discharging operation is used. It is preferable that the medium is relatively moved by an amount corresponding to the amount of the liquid. According to such a liquid ejection device, the degree of mixing of the liquid ejected by the ejection operation before and after the movement operation can be adjusted, so that the occurrence of stripes can be reduced.
[0015]
In this liquid ejecting apparatus, it is preferable that the amount of the liquid is an amount of the liquid to be ejected from the liquid ejecting unit in the ejecting operation performed between the moving operation and the moving operation. Further, at the time of a moving operation performed before or after a certain discharging operation, it is preferable that the medium is relatively moved by a moving amount corresponding to an amount of the liquid to be discharged in the discharging operation. According to such a liquid ejection device, the degree of mixing of the liquid ejected before and after the movement operation can be adjusted, so that the occurrence of stripes can be reduced.
[0016]
In such a liquid ejection device, the liquid ejection device performs the ejection operation a plurality of times on the medium, and the amount of the liquid is changed from the liquid ejection portion in the ejection operation of the plurality of times. Desirably, the amount of the liquid to be discharged. According to such a liquid ejecting apparatus, the moving amount is determined according to the amount of liquid ejected to the entire medium, so that the load of calculating the amount of liquid is reduced.
[0017]
In such a liquid ejection device, it is preferable that the ejection operation ejects liquid from a liquid ejection unit based on data, and the amount of the liquid be determined based on the data. According to such a liquid ejection apparatus, it is possible to determine the movement amount according to the amount of the ejected liquid before performing the ejection operation.
[0018]
In this liquid ejecting apparatus, the moving operation relatively moves the medium based on a target target amount, and the moving amount is the target amount corrected according to the amount of the liquid. Is determined based on According to such a liquid ejecting apparatus, by correcting the target amount according to the amount of the liquid, the medium can be moved by a moving amount corresponding to the amount of the liquid.
[0019]
In this liquid ejecting apparatus, the liquid ejecting apparatus forms a first test pattern by an amount of a first liquid, and a second test pattern by an amount of a second liquid different from the amount of the first liquid. It is desirable to form Further, it is preferable that information on a first movement amount based on the first test pattern and information on a second movement amount based on the second test pattern be stored. According to such a liquid ejecting apparatus, it is possible to store two pieces of information for calculating the movement amount according to the amount of the liquid. Further, it is preferable that a movement amount according to an amount of the liquid to be ejected to the medium is calculated based on the information regarding the first movement amount and the information regarding the second movement amount. According to such a liquid ejecting apparatus, the medium can be moved by a moving amount suitable for the amount of the liquid to be ejected without storing information on the amount of movement corresponding to the amount of the liquid to be ejected. .
[0020]
=== Causes of banding ===
In the present embodiment, the occurrence of banding (stripes along the scanning direction) is suppressed. Therefore, banding will be described below.
[0021]
<About banding>
FIG. 13A is an explanatory diagram of a dot row (also called a raster line) formed on printing paper. In the figure, dot rows are formed on a printing paper as a medium such as paper by a band printing method. The “band printing method” is a printing method in which a continuous dot row is formed by one pass. “Pass” refers to an operation in which the head moves in the scanning direction and intermittently ejects ink during the movement.
[0022]
In the present embodiment, in a certain printing operation (pass), the nozzle # n-2 forms the dot row L1, the nozzle # n-1 forms the dot row L2, and the nozzle #n forms the dot row L3. Further, after the printing paper P is conveyed and the nozzles and the printing paper P relatively move, in the next printing operation, the nozzle # 1 forms the dot row L4, and the nozzle # 2 forms the dot row L5. , Nozzle # 3 forms a dot row L6. It should be noted that the illustration of the dot rows formed by other nozzles is omitted in FIG. Further, in FIG. 3, two heads 21 are drawn to show the relative positional relationship between the paper and the head before and after the transport operation.
[0023]
Each dot row is formed in a line along the scanning direction by the nozzle moving in the scanning direction and intermittently ejecting ink (this is also referred to as a “raster line”). Since the diameter of each dot is larger than the interval between the dot rows, each dot row slightly overlaps. In the figure, D is the nozzle interval (nozzle pitch), and in this embodiment, is also the pixel interval (dot interval) in the transport direction. Dp is the pixel interval (dot interval) in the scanning direction. The interval between the dot rows L1 and L2, the interval between the dot rows L2 and L3, the interval between the dot rows L4 and L5, and the interval between the dot rows L5 and L6 are determined by the interval between the nozzles. equal. However, the interval Dc between the dot rows L3 and L4 is an interval that can be adjusted according to the transport amount of the printing paper P (the relative movement amount between the printing paper P and the nozzles).
[0024]
Generally, it has been considered that the cause of the banding is that the transport amount of the transport operation performed between the printing operation (pass) and the printing operation is not accurate. That is, since the interval Dc between the dot rows L3 and L4 is not equal to the nozzle pitch D, it has been considered that banding occurs between the dot rows L3 and L4.
However, even if the interval Dc between the dot rows L3 and L4 is equal to the nozzle pitch D, banding occurs due to the difference in the degree of ink mixing between the dot rows. Hereinafter, this point will be described.
[0025]
<About how ink mixes>
In FIG. 13A, dot rows L1, L2 and L3 are formed almost simultaneously. Similarly, the dot rows L4, L5 and L6 are formed almost simultaneously. As described above, the degree of mixing of the inks between the dot rows formed almost simultaneously is almost the same because the printing conditions are the same. Therefore, banding is unlikely to occur between dot rows formed almost simultaneously.
[0026]
On the other hand, the dot rows L3 and L4 are formed by different printing operations. That is, the dot rows L3 and L4 are formed in a different time. Therefore, after the dot row L3 is formed and the ink dries, the dot row L4 is formed. As a result, the degree of ink mixing between the dot rows L3 and L4 is different from the degree of ink mixing between the other dot rows. As described above, when the way of mixing ink between certain dot rows is different from the way of mixing ink between other dot rows, banding is likely to occur.
[0027]
Therefore, the distance Dc is adjusted by adjusting the transport amount of the printing paper P (the relative movement amount between the printing paper P and the nozzles) to reduce the occurrence of banding.
However, as described below, the optimum interval Dc under certain conditions may not always be optimum under other conditions.
[0028]
<Relationship between ink amount and degree of ink mixing>
The relationship between the amount of ejected ink and the degree of mixing of the ink will be described. FIG. 13A is an explanatory diagram of a dot row formed on the printing paper P when dots are formed in 80% of the pixels (hereinafter, referred to as “duty of 80%”). FIG. 13B is an explanatory diagram of a dot row formed on the printing paper P when dots are formed in 50% of pixels (hereinafter, referred to as “duty of 50%”). The “pixel” is a square grid virtually defined on the printing paper P in order to define a position where an ink droplet lands and a dot is recorded. The black-out area in the drawing indicates an area where ink is mixed between the dot rows L3 and L4.
[0029]
In the present embodiment, all dots have the same diameter for simplification of the description. However, as can be seen from a comparison between FIG. 13A and FIG. 13B, if the number of dots is different, the degree of mixing of ink between the dot rows L3 and L4 is different even though the dot diameter is the same. As described above, if the amount of ink to be ejected (the number of dots) is different, the degree of mixing of ink between the dot rows L3 and L4 is different (the shape of the black-out area is different).
[0030]
This means that the optimum interval Dc is different between the case where the duty is 80% and the case where the duty is 50%. In other words, the case where the duty is 80% and the case where the duty is 50% mean that it is necessary to change the transport amount of the transport operation performed between the printing operations. If the optimum interval Dc in the case of the duty of 80% is applied to the case of the duty of 50%, white stripes (white banding) occur on the printing paper. Further, if the optimum interval Dc in the case of the duty of 50% is applied to the case of the duty of 80%, black stripes (black banding) occur on the printing paper.
Therefore, in the present embodiment, the conveyance amount is changed according to the amount of ink to be ejected, and the interval Dc is adjusted to the optimal amount for the amount of ink to be ejected, thereby reducing the occurrence of banding.
[0031]
=== Overview of the device ===
FIG. 1 is a schematic configuration diagram of a printing system including an inkjet printer. FIG. 2 is a block diagram showing a configuration of the ink jet printer centering on a control circuit.
The inkjet printer 1 (hereinafter, referred to as a printer 1) is a printing device that discharges ink from nozzles and prints an image on printing paper. The printer 1 includes a transport unit 10, a carriage unit 20, a head unit 30, an operation panel 40, and a controller 50.
[0032]
The transport unit 10 transports the printing paper P to a printable position. When printing the printing paper P, the transport unit 10 intermittently transports the printing paper P by a predetermined transport amount (the direction in which the transport unit 10 transports the printing paper P is referred to as a transport direction). The transport unit 10 has a transport motor 12 and a transport roller 14. The transport motor 12 generates a rotational driving force. The transport roller 14 is rotated by the rotational driving force of the transport motor 12, and transports the printing paper P in the transport direction. The transport of the printing paper P by the transport unit 10 will be described later in detail.
[0033]
The carriage unit 20 is a device for reciprocating the carriage in the scanning direction. That is, the carriage unit 20 moves the nozzles that eject ink by moving the carriage in the scanning direction. The scanning direction is a direction parallel to the left-right direction in FIG. 1 and a direction crossing the transport direction. The carriage unit 20 includes a carriage 21, a carriage motor 22, a pulley 23, a belt 24, a guide 25, and a position sensor 26. The carriage 21 can reciprocate along the scanning direction. In addition, the carriage 21 can mount an ink cartridge 70 that stores ink. The carriage motor 22 generates a driving force for moving the carriage 21 along the scanning direction. The carriage motor 22 can switch between normal rotation and reverse rotation so that the carriage 21 can reciprocate in the scanning direction.
[0034]
The pulley 23 is attached to a rotation shaft of the carriage motor 22 and is rotated by the carriage motor 22. The belt 24 is driven by the pulley 23. Since a part of the belt 24 and a part of the carriage 21 are joined, when the carriage motor 22 rotates, the belt 24 is driven via the pulley 23, and the carriage 21 moves in the scanning direction. The guide 25 is a rod-shaped member having a circular cross section, and is a guide member for guiding the carriage 21 along the scanning direction. The movement of the carriage 21 in the rotation direction about the scanning direction is restricted by the guide 25 and a part of the belt 24. The position sensor 26 detects the origin position of the carriage 21 (the origin position in the scanning direction). The carriage unit 20 also has a linear encoder (not shown) and the like. The linear encoder detects a relative position (a relative position in the scanning direction) of the carriage 21 with respect to the origin position.
[0035]
The head unit 30 is a device for discharging ink onto the printing paper P, and has a head 31 provided with a plurality of nozzles and driving elements. Since the head 31 is provided integrally with the carriage 21, when the carriage 21 moves in the scanning direction, the head 31 also moves in the scanning direction. Therefore, when ink is intermittently ejected from the nozzles of the head 31 while the carriage 21 is moving, the ink droplets sequentially land on the printing paper P, and a row of linear dots is formed on the printing paper P. The head unit 30 also has an introduction pipe, an ink flow path (described later), and the like.
[0036]
The operation panel 40 has a plurality of operation buttons and a lamp including a light emitting element such as an LED. The operator can directly input printing conditions to the printer 1 by pressing an operation button. The lamp is used, for example, to emit a red LED to notify an operator of an abnormality.
[0037]
The controller 50 controls the printer 1. In particular, the controller 50 transfers signals to the transport unit 10, the carriage unit 20, the head unit 30, and the operation panel 40, and controls each unit. The controller 50 includes a CPU 51, a RAM 52, a ROM 53, and an EEPROM 54, and forms an arithmetic and logic operation circuit. The CPU 51 is for controlling the entire printer 1 and gives a control command to each unit. The RAM 52 secures a work area for the CPU 51. The ROM 53 is storage means for storing a program. Various operations of the printer 1 described later are realized by programs stored in the ROM 53. Further, the ROM 53 records information on test patterns and printer fonts. Then, when the printer 1 receives the information specifying the test pattern or the character, the printer 1 refers to the information stored in the ROM 53 and outputs the corresponding test pattern or character. The EEPROM 54 is a nonvolatile semiconductor memory, and is a storage unit that stores a correction amount for correcting the transport amount.
[0038]
Further, the controller 50 includes an I / F dedicated circuit 55, a motor drive circuit 56, and a head drive circuit 57. The I / F dedicated circuit 55 performs an interface exclusively. The motor drive circuit 56 is connected to the I / F dedicated circuit 55 and drives the transport motor 12 and the carriage motor 22 based on a signal from the CPU 51. The head drive circuit 57 is connected to the I / F dedicated circuit 55 and drives the head 31 based on a signal from the CPU 51.
[0039]
Note that the controller 50 is connected to the computer 5 via the connector 3. This computer is equipped with a driver for the printer 1. The driver of the printer 1 has a function as a user interface that accepts commands by operating input means such as a keyboard and a mouse, and presents various information in the printer 1 to an operator on a display screen.
[0040]
=== Head configuration ===
FIG. 3 is an explanatory diagram showing a schematic configuration inside the head. FIG. 4 is an explanatory diagram showing the structure of the piezo element 35 and the nozzle Nz. FIG. 5 is an explanatory diagram showing the arrangement of the nozzles Nz in the head.
[0041]
The carriage 21 includes a cartridge 70K for black ink (K), a cartridge 70C for dark cyan ink (C), a cartridge 70LC for light cyan ink (LC), and a cartridge 70M for dark magenta ink (M). And a cartridge 70LM for light magenta ink (LM) and a cartridge 70Y for yellow ink (Y). Since the configuration of the head for each color ink is almost the same, some description is omitted in the following description.
[0042]
Below the carriage 21, six head units 30 (30K, 30C, 30LC, 30M, 30LM, 30Y) are provided. Each head unit 30 has an introduction pipe 33 and an ink flow path 34. The introduction pipe 33 is inserted into a connection hole (not shown) provided in the cartridge 70 when the cartridge 70 is mounted on the carriage, and supplies ink to the head unit 30. The ink flow path 34 is a flow path for guiding the ink supplied from the cartridge 70 to the head 31.
[0043]
The head 31 is provided with a plurality of nozzles Nz. Each nozzle Nz is provided with a piezo element 35 as a drive element for driving each nozzle to eject ink droplets. Each of the nozzles functions as a liquid ejection unit for ejecting liquid ink.
[0044]
The piezo element 35 is an element that distorts the crystal structure due to the application of a voltage and converts electric-mechanical energy very quickly. When a voltage having a predetermined time width is applied between the electrodes provided at both ends of the piezo element 35, the piezo element 35 expands according to the voltage application time and deforms the side wall of the ink flow path 34. As a result, the volume of the ink passage 34 contracts in accordance with the expansion of the piezo element 35, and the ink corresponding to the contraction is ejected from the tip of the nozzle Nz as an ink droplet Ip. When the ink droplets Ip land on the printing paper P, dots are formed on the printing paper.
[0045]
The plurality of nozzles are arranged on the lower surface of the head 31 along the transport direction. These nozzles are arranged at regular intervals. Each nozzle is assigned a smaller number toward the downstream nozzle (# 1 to #n). The nozzle rows arranged in this manner are provided on the lower surface of the head for each color. The nozzle rows of each color are arranged so as to be adjacent in the scanning direction.
[0046]
During printing, the conveyance unit 10 intermittently conveys the printing paper P by a predetermined conveyance amount, and during the intermittent conveyance, the carriage 21 moves in the scanning direction and ink droplets are ejected from each nozzle. . In the present embodiment, the interval between the nozzles is 180 dpi.
[0047]
=== Head drive ===
The driving of the head 31 will be described with reference to FIGS. FIG. 6 is a block diagram showing a configuration inside the head drive circuit 57. FIG. 7 is a timing chart for explaining each signal. That is, FIG. 7 shows a timing chart of each signal of the original signal ODRV, the print signal PRT (i), and the drive signal DRV (i). In the figure, the numbers in parentheses at the end of each signal name indicate the number of the nozzle to which the signal is supplied. The configuration in FIG. 6 may be provided in another position of the controller 50, not in the head drive circuit.
[0048]
The head drive circuit 57 has an original signal generation unit 572, a plurality of mask circuits 574, and a correction unit 576.
Original signal generating section 572 generates an original signal ODRV commonly used for nozzles # 1 to #n. The original signal ODRV is a signal including two pulses of the first pulse W1 and the second pulse W2 within the main scanning period for one pixel (the time when the carriage crosses the interval of one pixel). The original signal generator 572 outputs this original signal ODRV to each mask circuit 574.
[0049]
The mask circuit 574 is provided corresponding to a plurality of piezo elements that respectively drive the nozzles # 1 to #n of the head 31. Each mask circuit 574 receives the original signal ODRV from the original signal generator 572 and the print signal PRT (i). The print signal PRT (i) is a binary signal having two bits of information corresponding to one pixel, and is included in print data supplied from the personal computer to the printer. The mask circuit 574 cuts off the original signal ODRV according to the level of the print signal PRT (i). That is, when the print signal PRT (i) is at the 1 level, the mask circuit 574 passes the corresponding pulse of the original signal ODRV as it is to make the drive signal DRV. On the other hand, when the print signal PRT (i) is at the 0 level, the mask circuit 574 cuts off the pulse of the original signal ODRV. Then, the mask circuit 574 outputs the drive signal DRV (i) to the correction unit 576 based on the original signal ODRV and the print signal PRT (i).
[0050]
The drive signal DRV (i) is input to the correction unit 576. The correction unit 576 performs correction by shifting the timing of the waveform of the drive signal DRV (i). By correcting the timing of the waveform of the drive signal, the timing of ink ejection in the forward path and the return path of the movement of the carriage is corrected. Thereby, the positions of the dots formed on the printing paper P in the forward path and the backward path are corrected.
[0051]
FIG. 8 is an explanatory diagram of the timing of ink ejection on the outward path and the return path. Since this explanatory diagram is a diagram viewed from the transport direction, the direction perpendicular to the paper surface is the transport direction, and the horizontal direction on the paper surface is the scanning direction. The head 31 and the printing paper P face each other with a gap PG therebetween. The ink droplet Ip ejected from the head 31 flies by the distance of the gap PG and reaches the printing paper P. The ink droplets IP are ejected when the carriage 21 is moving, so that an inertial force acts. Therefore, in order to form dots at the target position on the printing paper P, it is necessary to eject ink from a position short of the target position. Since the moving directions are opposite between the forward path and the backward path, the ejection timing is different even when dots are formed at the same target position. The correction unit 576 corrects such a shift in the ink ejection timing between the forward path and the return path.
[0052]
The original signal ODRV sequentially generates a first pulse W1 and a second pulse W2 in each of the pixel sections T1, T2, and T3. Note that a pixel section has the same meaning as a scanning period for one pixel.
[0053]
When the print signal PRT (i) corresponds to 2-bit data "0, 1", only the first pulse W1 is output in the first half of one pixel section. Thus, small ink droplets are ejected from the nozzles, and small dots (small dots) are formed on the printing paper P. When the print signal PRT (i) corresponds to 2-bit data "1, 0", only the second pulse W2 is output in the latter half of one pixel section. Accordingly, a medium-sized ink droplet is ejected from the nozzle, and a medium-sized dot (medium dot) is formed on the printing paper P. When the print signal PRT (i) corresponds to 2-bit data "1, 1", the first pulse W1 and the second pulse W2 are output in one pixel section. As a result, large ink droplets are ejected from the nozzles, and large dots (large dots) are formed on the printing paper P. As described above, the drive signal DRV (i) in one pixel section is shaped so as to have three different waveforms depending on three different values of the print signal PRT (i).
[0054]
The print signal PRT (i) is similarly shaped whether it is a forward scan or a return scan of the main scan, as described above. However, although the same signal waveform is used for the forward scan and the return scan of the main scan, the timing is shifted and corrected by the correction unit 576 on the entire return scan. By this timing correction, the landing positions of the ink droplets are intentionally shifted throughout the return path, and the shift between the landing positions of the ink drops on the forward path and the return path is corrected.
[0055]
=== Conveyance of printing paper ===
<About the configuration of the transport unit>
FIG. 9 is an explanatory diagram for explaining the configuration of the transport unit 10.
The transport unit 10 sends the printing paper P to a printable position and moves the printing paper by a predetermined transport amount (movement amount) in the transport direction during printing. That is, the transport unit 10 functions as a transport mechanism that transports the printing paper. The transport unit 10 includes a transport free roller 15, a platen 16, a paper discharge roller 17, a paper discharge free roller 18, and a rotary encoder 19, in addition to the transport motor 12 and the transport roller 14.
[0056]
The transport free roller 15 is provided at a position facing the transport roller 14, and presses the print paper P toward the transport roller 14 by sandwiching the print paper P with the transport roller 14. The platen 16 supports the printing paper P being printed from below. The paper discharge roller 17 is a roller that discharges the printed printing paper P to the outside of the printer. The paper discharge roller 17 is driven by the conveyance motor 12 by a gear. That is, the transport motor 12 drives the transport roller 14 and also drives the paper discharge roller 17. The paper discharge free roller 18 is provided at a position facing the paper discharge roller 17, and presses the print paper P toward the paper discharge roller 17 by sandwiching the print paper P between the paper discharge roller 17.
[0057]
<About rotary encoder>
FIG. 10 is an explanatory diagram of the rotary encoder 19.
The rotary encoder 19 is for detecting the position of the carriage 41, and has a scale 191 and a detection unit 192.
[0058]
The scale 191 is provided with slits at predetermined intervals, and is provided on the transport roller 14 side. That is, when the transport roller 14 rotates, the scale 191 rotates together. In this embodiment, when the transport roller 14 rotates so as to transport the printing paper P by 1/1440 inch, the transport roller rotates by the slit interval of the scale 191.
[0059]
The detection unit 192 is provided to face the scale 191 and is fixed to the printer body. The detection unit 192 includes a light emitting diode 192A, a collimator lens 192B, and a detection processing unit 192C. The detection processing unit 192C includes a plurality (for example, four) of photodiodes 192D and a signal processing circuit 192E. And two comparators 192Fa and 192Fb.
[0060]
The light emitting diode 192A emits light when a voltage Vcc is applied thereto via the resistors at both ends, and this light is incident on the collimator lens. The collimator lens 192B converts the light emitted from the light emitting diode 192A into parallel light and irradiates the scale 191 with the parallel light. The parallel light that has passed through the slit provided on the scale passes through a fixed slit (not shown) and enters each photodiode 192D. The photodiode 192D converts incident light into an electric signal. The electric signals output from the respective photodiodes are compared in comparators 192Fa and 192Fb, and the comparison result is output as a pulse. Then, the pulses ENC-A and ENC-B output from the comparators 192Fa and 192Fb are output from the rotary encoder 19.
[0061]
FIG. 11A is a timing chart of the waveform of the output signal when the transport motor 12 is rotating forward. FIG. 11B is a timing chart of the waveform of the output signal when the transport motor 12 is reversed.
[0062]
As shown in FIGS. 11A and 11B, the phase of the pulse ENC-A and the phase of the pulse ENC-B are shifted by 90 degrees regardless of whether the transport motor 12 is rotating forward or reverse. When the transport motor 12 is rotating forward, that is, when the printing paper P is being transported in the transport direction, as shown in FIG. 11A, the phase of the pulse ENC-A is 90 degrees smaller than the phase of the pulse ENC-B. I'm advancing. On the other hand, when the transport motor 12 is reversed, that is, when the printing paper P is being transported in a direction opposite to the transport direction, as shown in FIG. 11B, the pulse ENC-A is longer than the pulse ENC-B. The phase is delayed by 90 degrees. One cycle T of each pulse is equal to the time during which the transport roller 14 rotates by the interval between slits of the scale 191 (for example, 1/1440 inch (1 inch = 2.54 cm)).
[0063]
<About transport of printing paper>
FIG. 12 is a flowchart for explaining the flow of transport of the printing paper. Various operations of the printer 1 (or the transport unit 10) described below are realized by programs stored in the ROM 53 in the printer 1. Further, this program is composed of codes for performing various operations described below.
[0064]
First, a target transport amount is set (S101). The target transport amount is a value that determines the drive amount of the transport unit 10 in order to transport the printing paper P by the transport amount targeted by the transport unit 10. The target carry amount is determined based on information on the target carry amount included in the print data received from the computer 5. Then, the target carry amount is set by setting the value of the counter. In the present embodiment, since the target transport amount is X, the value of the counter is set to X.
[0065]
Next, the transport motor 12 is driven (S102). When the transport motor 12 is driven, the transport rollers 14 rotate via gears. When the transport roller 14 rotates, the rotary encoder provided on the transport roller 14 also rotates.
[0066]
Next, the edge of the pulse signal of the rotary encoder is detected (S103). That is, first, a rising edge or a falling edge of the pulse ENC-A or ENC-B is detected. In the present embodiment, detecting one edge means that the conveyance roller conveys the printing paper P at 1/1440 inch.
[0067]
When the edge of the pulse signal of the rotary encoder is detected, the value of the counter is subtracted (S104). That is, when the edge of the pulse signal is detected when the value of the counter is X, the value of the counter is set to X-1.
[0068]
Then, the operations of S102 to S104 are repeated until the value of the counter becomes zero (S105). The transport motor 12 is driven until the number of pulses of the value set in the counter is detected first. Thereby, the transport unit 10 can transport the printing paper P in the transport direction by the transport amount according to the value initially set in the counter.
[0069]
For example, when the printing paper P is transported by 90/1440 inches, the value of the counter is set to 90 in order to set the target transport amount. Then, every time a rising edge or a falling edge of the pulse signal of the rotary encoder is detected, the value of the counter is decremented. Then, when the value of the counter becomes zero, the transport unit 10 ends the transport operation. Detecting 90 pulse signals means that the conveying roller conveys the printing paper P at 90/1440 inch. Therefore, if the value of the counter is set to 90 as the setting of the target transport amount, the transport unit 10 transports the printing paper P at 90/1440 inches.
[0070]
In the above description, the rising edge or the falling edge of the pulse ENC-A or ENC-B is detected, but both edges of the pulse ENC-A and the pulse ENC-B may be detected. Since the period of each of the pulse ENC-A and the pulse ENC-B is equal to the slit interval of the scale 191, and the phase of the pulse ENC-A and the phase of the pulse ENC-B are shifted by 90 degrees, the rising edge of each pulse and Detecting any of the falling edges means that the transport roller transports the printing paper at 1/5760 inch. In this case, if the value of the counter is set to 90, the transport unit 10 transports the printing paper P at 90/5760 inches. In the present embodiment described below, if the value of the counter is 1, the transport unit 10 transports the printing paper at 1/5768 inch.
[0071]
The above description relates to one transport operation. When a plurality of transport operations are performed intermittently, a target transport amount is set (a counter is set) each time each transport operation ends, and the printing paper P is transported according to the set target transport amount.
[0072]
Incidentally, the rotary encoder 19 directly detects the rotation amount of the transport roller 14 and does not detect the transport amount of the printing paper. However, when the transport roller 14 rotates and transports the printing paper P, a transport error occurs due to slippage between the transport roller 14 and the printing paper P. As described above, when the slippage occurs between the transport roller 14 and the printing paper P, in order to transport the printing paper P by the target transport amount, the transport roller 14 is driven by a transport amount larger than the target transport amount. There is a need to. Therefore, the printer of the present embodiment can correct the target transfer amount and set a counter to a value corresponding to the corrected target transfer amount in order to transfer the printing paper P by the optimum transfer amount.
[0073]
Further, in the present embodiment, as described below, the target transport amount is corrected according to the amount of ejected ink. Then, the value of the counter is set according to the corrected target carry amount, and the carry unit 10 carries the print sheet until the set counter value becomes zero.
[0074]
=== Method of Determining Correction Amount According to Ink Amount ===
First, before correcting the target carry amount according to the ink amount, it is necessary to determine a correction amount according to the ink amount. Therefore, a method of determining the correction amount according to the ink amount will be described below.
[0075]
<About printing test patterns>
FIG. 14 is a flowchart for explaining a method of printing a test pattern for carrying amount correction. Various operations of the printer described below are realized by programs stored in the ROM 53 in the printer. This program is composed of codes for performing various operations described below.
[0076]
First, the printer receives an instruction signal for instructing printing of a test pattern for carrying amount correction (S201). This instruction signal may be received from the computer main body or may be input from a button provided on the printer main body. When instructing printing of a test pattern from the computer main body, for example, a user interface as shown in FIG. 15 is displayed on a display device connected to the computer main body. In the window W1 displayed on the display device, a button for instructing printing of a test pattern is displayed. When the user clicks this button, a signal for instructing the printer 1 to print a test pattern is transmitted from the computer body.
[0077]
Next, the printer prints a test pattern for carrying amount correction (S202). The printer that has received the instruction signal searches the test patterns in the ROM 53 for information on the test pattern for correcting the carry amount. Then, the printer prints the test pattern on the printing paper P according to the information on the test pattern for carrying amount correction.
[0078]
FIG. 16 is an explanatory diagram of the test pattern printed on the printing paper P. However, since the rectangle drawn on the left side in the figure indicates the relative position of the head 31 with respect to the printing paper P, it is not printed on the printing paper P. As shown in the figure, a plurality of test patterns are printed on the printing paper P.
[0079]
Each test pattern is composed of two rectangular patterns (called “band patterns”). The two band patterns of the test pattern are formed adjacent to each other in the transport direction. Further, the two band patterns of the test pattern are formed shifted in the scanning direction in order to clarify the position of the boundary between the two band patterns. In the band pattern of the test pattern with a duty of 80%, dots are formed in 80% of the pixels. In the band pattern of the test pattern having a duty of 50%, dots are formed in 50% of the pixels. The 80% duty test pattern and the 50% duty test pattern are printed side by side along the scanning direction. Further, five test patterns for each duty are formed along the transport direction. The five test patterns are formed by changing the transport amount stepwise.
[0080]
In the present embodiment, as described below, five test patterns are formed by changing the transport amount stepwise by C (= 1/5760 inches). First, when the head 31 is at the position of the head 31A with respect to the printing paper P, the head 31A intermittently ejects ink while moving in the scanning direction, and the upper band of the test pattern numbered 1 is attached. Print the pattern. Then, the printing paper P is transported by the transport amount F + 2C, and the head 31 moves relatively to the position of the head 31B with respect to the printing paper P. When the head 31 is at the position of the head 31B with respect to the printing paper P, the head 31B intermittently discharges ink while moving in the scanning direction, and the lower band pattern of the test pattern numbered 1 is attached. To print. As a result, a test pattern with the number = 1 is formed on the printing paper P. Similarly, the test pattern numbered 2 is formed on the printing paper P with the conveyance of the conveyance amount F + C. Similarly, the test pattern numbered 3 is formed on the printing paper P with the conveyance of the conveyance amount F interposed. Similarly, the test pattern numbered 4 is formed on the printing paper P with the conveyance of the conveyance amount FC interposed. Similarly, the test pattern numbered 5 is formed on the printing paper P with the conveyance of the conveyance amount F-2C interposed. In this embodiment, the carry amount F means a carry amount corresponding to the length of the head, and is 1 inch. Further, in the present embodiment, the carry amount C means a reference correction amount serving as a reference of a correction amount for correcting the carry amount, and corresponds to 1/5760 inch which is a carry amount corresponding to the resolution of the rotary encoder.
[0081]
The five test patterns formed along the transport direction are formed by correcting the transport amounts by different correction amounts. As a result, the five test patterns formed along the transport direction have different boundary intervals between the two band patterns. Therefore, a test pattern in which white stripes (white banding) occurs, a test pattern in which black stripes (black banding) occurs, and a test pattern in which no stripes occur (the stripes are not visible) are printed.
[0082]
After printing the test pattern for carrying amount correction, the user selects an optimal pattern based on the printed test pattern (S203). The selection of the optimum pattern may be performed on the computer main body side or on the printer main body side. When an optimum pattern is selected on the computer main body side, for example, a user interface as shown in FIG. 17 is displayed on a display device connected to the computer main body. A plurality of buttons are displayed in the window W2 displayed on the display device so as to correspond to the printed test pattern. Then, when the user clicks this button, the test pattern corresponding to the clicked button is selected as the optimal pattern.
[0083]
In the present embodiment, one test pattern is selected from among the five 80% duty test patterns, and one test pattern is selected from among the five 50% duty test patterns. In the present embodiment, when the duty is 80%, the test pattern of number = 2 is selected as the optimal pattern. Further, in the present embodiment, when the duty is 50%, the test pattern of number = 4 is selected as the optimal pattern. As a result, in the present embodiment, optimal test patterns are selected for test patterns having different amounts of ink to be ejected.
[0084]
Next, a correction amount for correcting the transport amount is stored (stored) (S204). When an optimal pattern is selected on the computer main body side, information on the duty (information on the ink amount) and information on the correction amount corresponding to the pattern optimal for the duty (information on the transport amount) are stored in the computer main body side. Sent to the printer. Then, the printer stores the received information on the duty and the information on the correction amount in the EEPROM 54 in the printer in association with each other.
[0085]
In the present embodiment, the printer associates the duty of 80% with the correction amount (+ C) and associates the duty of 50% with the correction amount (-C) and saves them in the EEPROM 54 in the printer. .
[0086]
<Compensation method for correction amount>
As described above, the printer stores the correction amount for correcting the transport amount when the duty is 80% and the correction amount for correcting the transport amount when the duty is 50%. However, at the time of actual printing, the amount of ink ejected is not always the amount of ink corresponding to the stored correction amount. Therefore, it is necessary to supplement the correction amount for the conveyance amount correction corresponding to the amount of ink ejected at the time of actual printing.
[0087]
FIG. 18 is a graph showing the relationship between the amount of ink ejected and the correction amount. The horizontal axis is the ratio of pixels where ink lands (referred to as “duty”), and is related to the amount of ink ejected. The vertical axis indicates the correction amount for the target transport amount. It is already stored that the correction amount for a duty of 80% is + C and the correction amount for a duty of 50% is -C based on the test pattern described above.
[0088]
When the amount of ink to be ejected increases, the degree of mixing of ink increases, so that black banding (black stripes) easily occurs. Therefore, when the amount of ink to be ejected increases, it is necessary to make correction so that the carry amount increases, and to increase the interval Dc. On the other hand, when the amount of ink to be ejected is small, the degree of mixing of the ink is small, so that white banding (white stripes) is likely to occur. Therefore, when the amount of ejected ink decreases, it is necessary to correct the conveyance amount so as to reduce the amount and to reduce the interval Dc. That is, the relationship between the amount of ink to be ejected and the correction amount is substantially linear.
[0089]
Therefore, in the present embodiment, a correction amount corresponding to the amount of ink to be ejected is calculated by using the correction amounts for the two duties obtained based on the test pattern and creating a function as shown in the graph in FIG. I can do it. For example, when the amount of ink ejected at the time of actual printing is a duty of 35%, the correction amount for the target transport amount is calculated as -2C.
[0090]
The correction amount thus calculated is used when correcting the target transport amount. Then, a counter is set based on the target transport amount corrected according to the amount of ink to be ejected, and the printing paper is transported according to the set counter. As a result, the printing paper is transported by a transport amount corresponding to the amount of ink to be ejected.
[0091]
=== Correction of target transport amount according to ink amount ===
FIG. 19 is a flowchart for explaining the flow when forming an image on printing paper. Various operations of the printer described below are realized by programs stored in the ROM 53 in the printer. Various operations of the computer main body described below are realized by a printer driver which is a program stored in the computer main body. These programs are composed of codes for performing various operations described below.
[0092]
First, the user turns on the power of the printer and puts the printer in a print standby state (S311). Then, the user gives a print instruction from an application running on the computer (S301). When a user gives a print instruction to a computer, a print mode (print method) is set via a user interface of a printer driver. Therefore, the computer main body can determine the target transport amount based on the set print mode (S302).
[0093]
Further, the RGB image data to be printed is converted into CMYK binary data (S303). At this time, conversion from RGB data to CMYK data is performed by referring to a look-up table (LUT) in the printer driver. Next, raster data is created based on the CMYK data (S304). The raster data is data relating to a dot row corresponding to each nozzle, and corresponds to the above-described print signal PRT (i). Then, the computer main body transmits print data including data relating to the target transport amount and raster data to the printer (S305).
[0094]
The printer that has received the print data calculates the amount of ink to be ejected based on the raster data included in the print data (S312). As shown in the print signal PRT (i) in FIG. 7, the raster data is data corresponding to a column of pixels along the scanning direction, and is data in which 2-bit information is assigned to one pixel. On the other hand, in the present embodiment, the ratio (duty) of pixels in which dots are formed is used as a measure of the amount of ink to be ejected. Therefore, by calculating the number of pixels on which dots are formed based on the raster data, the amount of ink to be ejected can be calculated.
[0095]
That is, in the raster data, if two bits corresponding to one pixel are all zero, no dot is formed at that pixel (ink is not ejected). If two bits corresponding to one pixel are any one in the raster data, a dot is formed at that pixel (ink is ejected). By judging the presence or absence of dot formation for each pixel in this manner, the ratio (duty) of pixels in which dots are formed is determined, and the amount of ink ejected is determined.
[0096]
Next, the printer determines a correction amount for the target transport amount according to the obtained ink amount (S313). In the present embodiment, the correction amount for the target carry amount is determined according to the function shown in FIG. 18 based on the duty obtained from the raster data. For example, when the ink amount calculated based on the raster data is 35%, the correction amount for the target transport amount is determined to be -2C.
[0097]
Next, the printer performs a printing process with the corrected target transport amount according to the print data (S314). The correction of the target transport amount is performed by adding the correction amount determined in S313 from the target transport amount included in the received print data. Then, based on the corrected target transport amount, a counter value set when the transport unit 10 transports the printing paper is determined.
[0098]
For example, when the printing paper P is transported one inch at a time (when the target transport distance is 1 inch), the counter value becomes 5760 unless the target transport distance is corrected. However, when the ink amount calculated based on the raster data is 35%, the correction amount is -2C (-2/5760 inches). Therefore, the set value of the counter after the correction is 5758 (= 5760-2).
[0099]
In this way, the printer alternately repeats the ink ejection operation based on the raster data included in the print data and the conveyance operation according to the counter value (the conveyance operation with the corrected conveyance amount), and An image is formed on the substrate.
[0100]
According to the present embodiment, the target transport amount is corrected according to the amount of ink to be ejected. As a result, the interval between the dot arrays formed by different printing operations, for example, the interval between the dot arrays L3 and L4 shown in FIG. 13A is adjusted according to the amount of ink to be ejected. Thereby, the degree of mixing of the ink between the dot rows is adjusted, and the occurrence of banding can be suppressed.
[0101]
Further, according to the present embodiment, when the number of dots formed on the printing paper increases (when the duty% increases), the carry amount when carrying the printing paper intermittently increases (that is, the discharge amount from the nozzles). As the number of ink droplets to be increased increases, the transport amount increases). When the number of dots increases, for example, the amount of ink mixed between the dot rows L3 and L4 shown in FIG. 13A increases, and stripes are likely to occur. Suppress the occurrence of.
[0102]
Further, according to the present embodiment, the amount of ink ejected for each printing operation (pass) is calculated. When performing intermittent conveyance, the target conveyance amount is corrected for each conveyance operation in accordance with the amount of ink ejected in the printing operation performed between the conveyance operations. The target transport amount of each transport operation is corrected according to at least one of the ink amount of the printing operation performed before the transport operation and the ink amount of the printing operation performed after the transport operation. Is done. Further, according to the amount of ink ejected in a certain ejection operation, the target conveyance amount of the conveyance operation performed before and after the ejection operation is corrected. By correcting the target transport amount in this way, the degree of mixing of the ink ejected before and after the transport operation is adjusted, and the occurrence of banding can be suppressed.
[0103]
Further, according to the present embodiment, the printer stores the correction amounts corresponding to the two types of ink amounts based on the test patterns. Thus, the printer can determine the correction amount according to the amount of ink to be ejected when actually performing printing based on the two stored correction amounts. In the present embodiment, two types of test patterns having different ink amounts are created in order to determine the correction amounts according to the two types of ink amounts.
[0104]
Further, according to the present embodiment, the amount of ink to be ejected is calculated based on the raster data in the print data received from the computer. Thus, the amount of ink to be ejected can be calculated before the ink is ejected from the nozzle.
[0105]
=== Configuration of computer system etc. ===
Next, an embodiment of a computer system, a computer program, and a recording medium on which the computer program is recorded will be described with reference to the drawings.
[0106]
FIG. 20 is an explanatory diagram showing the external configuration of the computer system. The computer system 1000 includes a computer main body 1102, a display device 1104, a printer 1106, an input device 1108, and a reading device 1110. In the present embodiment, the computer main body 1102 is housed in a mini-tower type housing, but is not limited to this. The display device 1104 generally uses a cathode ray tube (CRT), a plasma display, a liquid crystal display device, or the like, but is not limited thereto. As the printer 1106, the printer described above is used. In the present embodiment, the input device 1108 uses the keyboard 1108A and the mouse 1108B, but is not limited thereto. In the present embodiment, the reading device 1110 uses the flexible disk drive device 1110A and the CD-ROM drive device 1110B, but is not limited thereto. For example, an MO (Magnet Optical) disk drive device or a DVD (Digital Versatile) Disk).
[0107]
FIG. 21 is a block diagram showing a configuration of the computer system shown in FIG. An internal memory 1202 such as a RAM and an external memory such as a hard disk drive unit 1204 are further provided in a housing in which the computer main body 1102 is stored.
[0108]
The above-described computer program for controlling the operation of the printer can be downloaded to a computer 1000 or the like connected to the printer 1106 via a communication line such as the Internet, or recorded on a computer-readable recording medium. Can also be distributed. As the recording medium, for example, various recording media such as a flexible disk FD, a CD-ROM, a DVD-ROM, a magneto-optical disk MO, a hard disk, and a memory can be used. Note that the information stored in such a storage medium can be read by various reading devices 1110.
[0109]
FIG. 22 is an explanatory diagram showing the user interface of the printer driver displayed on the screen of the display device 1104 connected to the computer system. The operator can use the input device 1108 to make various settings for the printer driver.
The operator can select a print mode (print method) from this screen. For example, the operator can select a high-speed printing mode or a fine printing mode as a printing mode, or can select a band printing method or a pseudo band printing method. Further, the operator can select a dot interval (resolution) for printing from this screen.
[0110]
FIG. 23 is an explanatory diagram of a format of print data supplied from the computer main body 1102 to the printer 1106. This print data is created from image information based on the settings of the printer driver. The print data has a print condition command group and a command group for each pass. The print condition command group includes a command indicating a print resolution, a command indicating a print direction (unidirectional / bidirectional), and the like. The print command group for each pass includes a target carry amount command CL and a pixel data command CP. The pixel data command CP includes pixel data PD indicating a recording state of each pixel of a dot recorded in each pass. Although the various commands shown in FIG. 1 each have a header section and a data section, they are illustrated in a simplified manner. Further, these command groups are intermittently supplied from the computer main body side to the printer side for each command. However, the print data is not limited to this format.
[0111]
In the above description, an example in which the printer 1106 is connected to the computer main body 1102, the display device 1104, the input device 1108, and the reading device 1110 to form a computer system has been described. However, the present invention is not limited to this. Absent. For example, the computer system may include the computer main body 1102 and the printer 1106, and the computer system does not need to include any of the display device 1104, the input device 1108, and the reading device 1110. Further, for example, the printer 1106 may have a part of the functions or mechanisms of the computer main body 1102, the display device 1104, the input device 1108, and the reading device 1110. As an example, the printer 1106 includes an image processing unit for performing image processing, a display unit for performing various displays, and a recording medium attaching / detaching unit for attaching / detaching a recording medium for recording image data captured by a digital camera or the like. It is good also as composition which has.
[0112]
The computer system implemented in this way is a system superior to the conventional system as a whole.
[0113]
=== Other Embodiments ===
Although the above embodiment mainly describes a printer, it includes an adjustment method, a printing apparatus, a printing method, a program, a storage medium, a computer system, a display screen, a screen display method, a method of manufacturing a printed matter, and adjustment. Needless to say, the disclosure includes a pattern for use, a recording device, a liquid ejection device, and the like.
[0114]
In addition, a printer and the like have been described as one embodiment. However, the above embodiment is for facilitating understanding of the present invention, and is not for limiting and interpreting the present invention. The present invention can be modified and improved without departing from the spirit thereof, and it goes without saying that the present invention includes its equivalents. In particular, the embodiments described below are also included in the present invention.
[0115]
<About ink amount 1>
According to the above-described embodiment, the target carry amount is corrected according to the ratio of pixels where dots are formed. That is, the number of dots formed on the printing paper is a measure of the amount of ink to be ejected. However, the standard of the amount of ink to be ejected is not limited to this. For example, the amount of ink to be ejected may be determined in consideration of the size of dots formed on the printing paper P (or the size of ink droplets ejected from the nozzles).
[0116]
FIG. 24 is an explanatory diagram of a dot row formed on the printing paper P. Compared to the case of FIG. 13A, the dot is formed in 80% of the pixels, but the diameter of the dot formed on the printing paper is small. As can be seen by comparing FIG. 13 with FIG. 13A, if the ejected ink droplets are small (the dots formed on the printing paper P are small), the amount of ink mixed between the dot rows decreases. Also, if the ejected ink droplets are small (the dots formed on the printing paper P are large), the amount of ink mixed between the dot rows increases. As described above, the degree of ink mixing differs depending on the size of the ink droplet ejected from the nozzle.
[0117]
Therefore, the amount of ink to be ejected is determined in consideration of the size of the ink droplet, and the target transport amount is corrected according to the amount of ink. Thereby, the degree of mixing of the inks between the dot rows is adjusted, and the occurrence of banding can be suppressed. When the ink droplets ejected from the nozzles become large, for example, the mixture of the inks between the dot rows L3 and L4 shown in FIG. 13A increases, and stripes are easily generated. Increase the spacing to suppress banding.
[0118]
Note that dots of different sizes may be formed on printing paper. When large dots, medium dots, and small dots are formed on printing paper, ink droplets of about 40 pl (picoliter), 21 pl, and 13 pl are respectively ejected from the nozzles. Therefore, for example, if the raster data (print signal PRT (i)) includes data for 30 large dots, 50 medium dots, and 70 small dots, the amount of ink ejected is (40 pl × 30) + (21 pl × 50) + (13 pl × 70) = 3160 pl.
[0119]
<About ink amount 2>
According to the above-described embodiment, the target transport amount is corrected according to the amount of ink ejected from all nozzles (nozzle # 1 to nozzle #n). However, when calculating the amount of ink to be ejected, it is not always necessary to target all nozzles.
For example, the target transport amount may be corrected according to the amount of ink ejected from the nozzles (# 1 and #n) at the end of the head 31. For example, in FIG. 13A, the dot rows L3 and L4 that cause banding are both formed by nozzles at the end of the head. As described above, when the dot rows formed by different printing operations are adjacent to each other, each dot row is formed by the nozzle at the end of the head. Therefore, if the transport amount is adjusted according to the amount of ink ejected from the nozzle at the end of the head, the occurrence of banding can be reduced.
In such an embodiment, even if the nozzles # 2 to # n-1 form dots in 80% of the pixels, the nozzles # 1 and #n form dots in 50% of the pixels. For example, the correction amount for the target transport amount is -C.
[0120]
<About the correction amount 1>
According to the above-described embodiment, the determination of the correction amount for the target transport amount is performed on the printer side. However, it is not limited to this. For example, a printer driver on the computer side may determine the correction amount for the target transport amount.
Further, according to the above-described embodiment, the correction of the target transport amount is performed on the printer side. However, it is not limited to this. For example, the printer driver on the computer side may correct the target carry amount and transmit information on the corrected target carry amount to the printer.
[0121]
FIG. 25 is a flowchart for explaining a flow when an image is formed on printing paper in another embodiment. Various operations of the printer described below are realized by programs stored in the ROM 53 in the printer. Various operations of the computer main body described below are realized by a printer driver which is a program stored in the computer main body. These programs are composed of codes for performing various operations described below. The description of the same operation as in the above-described embodiment will be omitted.
[0122]
In this embodiment, after the raster data is created (S304), the computer calculates the amount of ink to be ejected based on the raster data (S305). Next, the computer determines a correction amount for the target transport amount according to the ink amount (S306). Then, the computer corrects the target carry amount on the computer side, and transmits print data including the corrected target carry amount and raster data to the printer side (S307). The printer sets a counter based on the information on the corrected target transport amount included in the received print data, and performs a printing process (S312).
[0123]
Even in such a case, the same effect as that of the above-described embodiment can be obtained. Further, according to the present embodiment, since the calculation of the ink amount based on the raster data is performed on the computer side, the load of the calculation processing on the printer side is reduced.
[0124]
<About the correction amount 2>
According to the above-described embodiment, the correction amount determined based on the test pattern is stored in the EEPROM of the printer. However, the storage location of the correction amount is not limited to this. For example, the correction amount may be stored on the computer side. When the computer transmits the print data to the printer, the print data may include information about the correction amount (or the corrected target transport amount).
[0125]
<About the correction amount 3>
According to the above-described embodiment, assuming that the ink amount and the correction amount have a linear relationship, the correction amounts corresponding to the other ink amounts are complemented based on the correction amounts corresponding to the two types of ink amounts. Was. However, it is not limited to this.
For example, a quadratic function may be created based on correction amounts corresponding to three types of ink amounts, and a correction amount corresponding to the amount of ink to be ejected may be determined based on the quadratic function. Further, for example, a lookup table in which the amount of ink to be ejected and the amount of correction are associated with each other is stored in the ROM 53 in the printer or a memory in the computer main body. The quantity may be determined.
[0126]
<Transport operation 1>
According to the above-described embodiment, the printing paper P and the head 31 are relatively moved along the transport direction by the transport unit 10 transporting the printing paper P. However, the relative movement between the two is not limited to this. For example, by moving the head in the transport direction, the two may be relatively moved along the transport direction.
[0127]
<Transport operation 2>
According to the above-described embodiment, the amount of ink to be ejected is calculated for each printing operation (pass), and the target transport amount is corrected according to the amount of ink for each printing operation. However, the present invention is not limited to calculating the amount of ink ejected for each printing operation.
For example, the target transport amount may be corrected uniformly by calculating the amount of ink ejected to the entire printing paper. That is, a correction amount corresponding to the total amount of ink ejected in a plurality of printing operations may be determined, and intermittent conveyance may be performed using the correction amount.
[0128]
<About test patterns>
In the above-described embodiment, a test pattern having two types of ink amounts is printed on one print sheet to determine a correction amount according to two types of ink amounts. However, the test pattern is not limited to this.
For example, first, only a test pattern with a duty of 80% is printed on printing paper, a correction amount for a duty of 80% is determined, and then, only a test pattern with a duty of 50% is printed on another printing paper, and a duty 50% is printed. The correction amount in the case of% may be determined. That is, test patterns with different ink amounts may be printed separately and sequentially.
[0129]
<About printing method>
In the above-described embodiment, the dot row is formed by the band printing method. However, the printing method is not limited to band printing. For example, the printing method may be a pseudo band printing method.
[0130]
FIG. 26 is an explanatory diagram of a dot row formed by the pseudo band printing method. The “pseudo-band printing method” is a printing method in which a continuous dot row is completed by a plurality of passes (printing operations). In this embodiment, a continuous dot row is completed by two passes. Since the interval between the nozzles is 180 dpi, the interval D between the dot rows formed on the printing paper is 360 dpi.
[0131]
In the present embodiment, in pass 1, the nozzle # n-1 forms the dot row L1, and the nozzle #n forms the dot row L3. Further, after the printing paper P is transported at the dot interval D, in pass 2, the nozzle # n-1 forms the dot row L2, and the nozzle #n forms the dot row L4. By pass 1 and pass 2, continuous dot rows L1 to L4 are completed. That is, by the printing operation of pass 1 and pass 2, band printing is performed by a pseudo head having a nozzle interval of 360 dpi. Next, in the present embodiment, in pass 3, the nozzle # 1 forms the dot row L5, and the nozzle # 2 forms the dot row L7. After the printing paper P is transported at the dot interval D, in pass 2, the nozzle # 1 forms a dot row L6, and the nozzle # 2 forms a dot row L8. In other words, by the printing operation of pass 3 and pass 4, band printing is performed by a pseudo head with a nozzle interval of 360 dpi.
[0132]
In the case of this embodiment, the mixing of ink between the dot rows L4 and L5 is different from the mixing of ink between the other dot rows. Therefore, in order to reduce the occurrence of banding, it is necessary to adjust the transport amount of the printing paper from pass 2 to pass 3 and to adjust the distance Dc between the dot rows L4 and L5.
[0133]
Therefore, in the case of the present embodiment, the target transport amount in the transport from pass 3 to pass 4 is corrected according to the amount of ink to be ejected. That is, in the case of pseudo band printing, the transport amount from the pass in which the pseudo band is completed to the pass in which the formation of the next pseudo band is started is corrected according to the amount of ink to be ejected. Thereby, the same effect as in the above-described embodiment can be obtained.
[0134]
<About the liquid ejection device>
In the above-described embodiment, the printer is described as the liquid ejection device, but the invention is not limited to this. For example, a recording device, a color filter manufacturing device, a dyeing device, a fine processing device, a semiconductor manufacturing device, a surface processing device, a three-dimensional modeling machine, a liquid vaporizer, an organic EL manufacturing device (especially a polymer EL manufacturing device), a display manufacturing device The same technology as that of the present embodiment may be applied to various types of liquid ejection devices to which an inkjet technology is applied, such as a film forming device and a DNA chip manufacturing device. These methods and manufacturing methods are also within the scope of application.
[0135]
<About ink>
Since the above-described embodiment is an embodiment of the printer, the dye ink or the pigment ink is ejected from the nozzle. However, the liquid ejected from the nozzle is not limited to such ink. For example, a liquid (including water) including a metal material, an organic material (especially a polymer material), a magnetic material, a conductive material, a wiring material, a film forming material, an electronic ink, a processing solution, a gene solution, and the like is discharged from the nozzle. May be. If such a liquid is directly discharged toward an object, material saving, process saving, and cost reduction can be achieved.
[0136]
<About the nozzle>
In the above-described embodiment, ink is ejected using the piezoelectric element. However, the method of discharging the liquid is not limited to this. For example, another method such as a method of generating bubbles in a nozzle by heat may be used.
[0137]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the high quality apparatus which can suppress that a stripe produces on the medium which discharged the liquid can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a printing system including a printer.
FIG. 2 is a block diagram mainly showing a controller.
FIG. 3 is an explanatory diagram showing a schematic configuration inside a head.
FIG. 4 is an explanatory diagram showing a structure of a piezo element and a nozzle.
FIG. 5 is an explanatory diagram showing an arrangement of nozzles in a head.
FIG. 6 is a block diagram showing a configuration inside a head drive circuit.
FIG. 7 is a timing chart of each signal.
FIG. 8 is an explanatory diagram of the timing of ink ejection in a forward pass and a return pass.
FIG. 9 is an explanatory diagram illustrating a configuration of a transport unit.
FIG. 10 is an explanatory diagram of a rotary encoder.
FIG. 11A is a timing chart of a waveform of an output signal during normal rotation. FIG. 11B is a timing chart of the waveform of the output signal at the time of inversion.
FIG. 12 is a flowchart illustrating the flow of printing paper conveyance.
FIG. 13A and FIG. 13B are explanatory diagrams of a dot row formed on printing paper.
FIG. 14 is a flowchart for explaining a test pattern printing method.
FIG. 15 is an explanatory diagram of a display of the display device.
FIG. 16 is an explanatory diagram of a test pattern.
FIG. 17 is an explanatory diagram of a display on the display device.
FIG. 18 is a graph showing the relationship between the amount of ink ejected and the correction amount.
FIG. 19 is a flowchart when an image is formed on printing paper.
FIG. 20 is an external configuration diagram of a computer system.
FIG. 21 is a block diagram illustrating a configuration of a computer system.
FIG. 22 is an explanatory diagram of a user interface of the printer driver.
FIG. 23 is an explanatory diagram of a format of print data.
FIG. 24 is an explanatory diagram of a dot row formed on printing paper.
FIG. 25 is a flowchart when an image is formed on printing paper.
FIG. 26 is an explanatory diagram of a dot row in a pseudo band printing method.
[Explanation of symbols]
1 Printer 3 Connector 5 Computer
10 transport unit 12 transport motor 14 transport roller
20 Carriage unit 21 Carriage 22 Carriage motor
23 Pulley 24 Belt 25 Guide
26 position sensor 30 head unit 31 head
40 operation panel 50 controller 51 CPU
52 RAM 53 ROM 55 I / F dedicated circuit
56 motor drive circuit 57 head drive circuit 70 cartridge
P printing paper

Claims (25)

A liquid discharging apparatus that alternately repeats a discharging operation of discharging liquid from a liquid discharging unit and a moving operation of moving a medium relative to the liquid discharging unit,
A liquid discharging apparatus, wherein the medium is relatively moved by a moving amount corresponding to an amount of the liquid to be discharged onto the medium during the moving operation. The liquid ejection device according to claim 1,
The amount of liquid is related to the number of dots to be formed on the medium. The liquid ejection device according to claim 2, wherein
As the number of the dots increases, the moving amount increases. The liquid ejection device according to claim 1,
The amount of the liquid is related to the number of droplets to be ejected from the liquid ejection unit. The liquid ejection device according to claim 4, wherein
As the number of the droplets increases, the moving amount increases. The liquid ejection device according to claim 1, wherein:
The amount of liquid is related to the size of the dots to be formed on the medium. The liquid ejection device according to claim 6,
As the size of the dot increases, the amount of movement increases. The liquid ejection device according to claim 1, wherein:
The amount of the liquid is related to a size of a droplet to be ejected from the liquid ejection unit. The liquid ejection device according to claim 8, wherein:
As the size of the droplet increases, the amount of movement increases. The liquid ejection device according to claim 1, wherein:
The liquid ejection device includes a plurality of the liquid ejection units,
The medium is relatively moved by the moving amount according to the amount of the liquid to be discharged from the plurality of liquid discharging units. The liquid ejection device according to claim 1, wherein:
The liquid ejection device includes a plurality of the liquid ejection units,
The medium is relatively moved by an amount of the liquid to be discharged from a part of the plurality of liquid discharge units. The liquid ejection device according to claim 11, wherein
The plurality of liquid ejection units are arranged in a row,
The part of the liquid ejection units is the liquid ejection units arranged at an end of the plurality of liquid ejection units arranged. The liquid ejection device according to claim 12, wherein
The dots formed by the liquid discharge units arranged at one end and the dots formed by the liquid discharge units arranged at the other end are formed adjacent to each other on the medium. The liquid ejection device according to claim 1,
The amount of the liquid is an amount of the liquid to be discharged from the liquid discharge unit in the discharging operation performed between the moving operation and the moving operation. The liquid ejection apparatus according to claim 14, wherein
In a moving operation performed before or after a certain discharging operation, the medium is relatively moved by a moving amount corresponding to an amount of the liquid to be discharged in the discharging operation. The liquid ejection device according to claim 1,
The liquid ejection device performs the ejection operation a plurality of times to the medium,
The amount of the liquid is an amount of the liquid to be ejected from the liquid ejection unit in the plurality of ejection operations. The liquid ejection device according to any one of claims 1 to 16,
The discharging operation is to discharge liquid from a liquid discharging unit based on data,
The amount of the liquid is determined based on the data. The liquid ejection device according to any one of claims 1 to 17,
The moving operation is to relatively move the medium based on a target amount to be targeted,
The moving amount is determined based on the target amount corrected according to the amount of the liquid. The liquid ejection device according to any one of claims 1 to 18, wherein
The liquid ejection device,
Forming a first test pattern with the amount of the first liquid;
A second test pattern is formed with an amount of the second liquid different from the amount of the first liquid. The liquid ejection device according to claim 19, wherein
The liquid ejection device stores information on a first movement amount based on the first test pattern and information on a second movement amount based on the second test pattern. The liquid ejection device according to claim 20, wherein
Based on the information on the first movement amount and the information on the second movement amount, a movement amount according to an amount of the liquid to be ejected to the medium is calculated. A liquid discharging apparatus that alternately repeats a discharging operation of discharging liquid from a liquid discharging unit and a moving operation of moving a medium relative to the liquid discharging unit,
At the time of the moving operation, the medium is relatively moved by a moving amount corresponding to the amount of the liquid to be ejected to the medium,
The amount of liquid is related to the number of dots to be formed on the medium, and as the number of dots increases, the amount of movement increases,
The amount of the liquid is related to the number of droplets to be ejected from the liquid ejection unit, and as the number of the droplets increases, the amount of movement increases,
The amount of the liquid is related to the size of a dot to be formed on the medium, and the larger the dot, the larger the amount of movement;
The amount of the liquid is related to the size of the droplet to be ejected from the liquid ejection unit, and the larger the droplet, the larger the amount of movement,
The liquid ejecting apparatus includes a plurality of the liquid ejecting units, and relatively disperses the medium in an amount of the liquid to be ejected from a part of the plurality of the liquid ejecting units. Move,
The plurality of liquid ejection units are arranged in a row, and the part of the liquid ejection units is the liquid ejection unit arranged at an end of the arranged plurality of liquid ejection units. Yes,
The dots formed by the liquid ejection units arranged at one end and the dots formed by the liquid ejection units arranged at the other end are formed adjacent to each other on the medium,
The amount of the liquid is an amount of the liquid to be discharged from the liquid discharge unit in the discharging operation performed between the moving operation and the moving operation,
In a movement operation performed before or after a certain ejection operation, the medium is relatively moved by a movement amount according to an amount of the liquid to be ejected in the ejection operation,
The discharge operation is to discharge liquid from a liquid discharge unit based on data, the amount of the liquid is determined based on the data,
The moving operation is to relatively move the medium based on a target target amount, the moving amount is determined based on the target amount corrected according to the amount of the liquid, is determined,
The liquid ejecting apparatus forms a first test pattern with an amount of a first liquid, and forms a second test pattern with an amount of a second liquid different from the amount of the first liquid. Storing information about a first movement amount based on the pattern and information about a second movement amount based on the second test pattern;
A liquid ejecting apparatus comprising: calculating a movement amount according to an amount of the liquid to be ejected to the medium, based on the information regarding the first movement amount and the information regarding the second movement amount. A liquid discharging method that alternately repeats a discharging operation of discharging liquid from a liquid discharging unit and a moving operation of moving a medium relative to the liquid discharging unit,
A liquid discharging method, wherein the medium is relatively moved by a moving amount according to an amount of the liquid to be discharged onto the medium during the moving operation. A liquid discharge device that alternately repeats a discharge operation of discharging liquid from a liquid discharge unit and a movement operation of moving a medium relative to the liquid discharge unit,
A program for realizing a function of relatively moving the medium by a moving amount corresponding to an amount of the liquid to be ejected to the medium at the time of the moving operation. A computer system comprising a computer body and a liquid ejection device,
The liquid ejection device,
A discharge operation of discharging liquid from the liquid discharge unit and a movement operation of moving the medium relative to the liquid discharge unit are alternately repeated,
A computer system, wherein the medium is relatively moved by a movement amount corresponding to an amount of the liquid to be ejected to the medium during the movement operation.

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