JP2004249599A - Liquid injection device and control method for the device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a liquid from being discharged too much or too little as compared with an originally required liquid amount at the time of carrying out a desired process by discharging liquid droplets to an object to be processed. <P>SOLUTION: There are set a liquid injection head for discharging the liquid droplets to the object to be processed from a nozzle opening by generating a pressure variation to the liquid in a pressure chamber, a scanning means for changing a relative positional relation between the object in the middle of the process and the liquid injection head, and a control means for controlling the liquid injection head to discharge the liquid droplets from the nozzle opening. The control means makes smaller a weight of the liquid to be discharged from the liquid injection head for forming one dot as a dot formation time difference which is a time interval from a time point when a preceding dot is precedently formed to the object to a time point when a succeeding dot which overlaps at least partially with the preceding dot is formed is shorter. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a liquid ejecting apparatus that ejects liquid droplets from nozzle openings of a liquid ejecting head, and a control method for the same.
[0002]
[Prior art]
As a typical example of a conventional liquid ejecting apparatus, there is an ink jet recording apparatus provided with an ink jet recording head for image recording. Other liquid ejecting apparatuses include, for example, an apparatus provided with a color material ejecting head used for manufacturing a color filter such as a liquid crystal display, an electrode material (conductive paste) used for forming an electrode such as an organic EL display and an FED (surface emitting display). Examples of the apparatus include an apparatus equipped with an ejection head, an apparatus equipped with a biological organic substance ejection head used for biochip production, and an apparatus equipped with a sample ejection head as a precision pipette.
[0003]
An ink jet recording apparatus, which is a typical example of a liquid ejecting apparatus, includes a recording head having a large number of nozzle openings formed in a row and a carriage mechanism (a main scanning mechanism) for moving the recording head in a main scanning direction. ) And a paper feed mechanism (sub-scanning mechanism) for moving the recording paper in the sub-scanning direction.
[0004]
The recording head includes a pressure chamber communicating with the nozzle opening and a pressure generating element for changing the ink pressure in the pressure chamber. In this recording head, a driving pulse (ejection pulse) generated from the driving signal is supplied to the pressure generating element to change the ink pressure in the pressure chamber and eject an ink droplet from the nozzle opening.
[0005]
The ejection of the ink droplets from the nozzle openings is performed toward the recording area at a timing specified by the dot pattern data while moving the recording head in the main scanning direction by the carriage mechanism. Then, when the recording head reaches the end of the movement range, the paper feeding mechanism moves the recording paper in the sub-scanning direction. After the recording paper is moved, the carriage mechanism moves the recording head again in the main scanning direction, and the recording head ejects ink droplets toward the recording area during the movement.
[0006]
By repeating the above operation, an image based on the dot pattern data is recorded on the recording paper.
[0007]
The above-described ink jet recording apparatus forms an image based on whether or not to eject ink droplets, that is, whether or not there are dots. For this reason, this printing apparatus employs a method of expressing an intermediate gradation by expressing one pixel with a plurality of dots such as 4 × 4, 8 × 8, and the like. In order to print a high-quality image by this method, not only large-volume ink droplets but also medium-volume ink droplets and even small-volume ink droplets are ejected from the recording head. Various types of dots such as dots, medium dots, and small dots can be formed on recording paper. There is also a technique for forming one dot with a plurality of ink droplets. In this case, a technique for forming one dot with a plurality of ink drops having the same volume, or a technique for forming one dot with a plurality of ink drops having different volumes. And the like.
[0008]
In addition, the ink jet recording apparatus appropriately selects a unidirectional ejection mode in which ink droplets are ejected only in the forward path in the main scanning direction, and a bidirectional ejection mode in which ink droplets are ejected in both the outward path and the backward path in the main scanning direction. Some models are possible. The one-way ejection mode easily achieves high image quality, but has the disadvantage that the printing speed is slow. Conversely, in the bidirectional ejection mode, high image quality is difficult to achieve, but there is an advantage that the printing speed can be increased. Therefore, the one-way ejection mode and the two-way ejection mode can be used depending on the purpose of printing.
[0009]
By the way, in an ink jet recording apparatus, an image is formed by forming a plurality of dots on a recording medium, and while a previously formed dot (preceding dot) has a small degree of drying, a subsequent dot is formed. In some cases, a dot (subsequent dot) that partially overlaps a preceding dot when an ink droplet lands is formed. This is particularly remarkable in so-called “solid printing” in which the entire target area is painted with ink.
[0010]
In general, when an ink droplet lands on a recording medium to form a dot, the dot bleeds in the surface direction of the recording paper to increase its diameter (a bleeding effect). When a subsequent dot is formed so as to partially overlap a preceding dot having a small degree of drying, the above-described bleeding effect on a recording medium is promoted, and the range in which the subsequent dot spreads tends to increase. There is.
[0011]
That is, the shorter the dot formation time difference from the time of forming the preceding dot to the time of forming the succeeding dot at least partially overlapping the preceding dot, the greater the blurring effect of the succeeding dot accelerated by the presence of the preceding dot. . Therefore, when solid printing is performed on a predetermined target area, the weight of the ink for forming one dot can be set to be smaller as the above-described dot formation time difference is shorter.
[0012]
[Patent Document 1]
JP-A-6-226963
[Patent Document 2]
JP-A-8-192512
[0013]
[Problems to be solved by the invention]
However, in a conventional ink jet recording apparatus, for example, in a model that can appropriately select a one-way ejection mode and a two-way ejection mode, one dot determined on the assumption that solid printing is performed in the one-way ejection mode is used. The weight of the ink to be formed is diverted as it is in the bidirectional ejection mode. In the bidirectional ejection mode, the bleeding effect of the subsequent dots is greater than in the one-way ejection mode. Therefore, if solid printing is performed using the ink weight determined on the premise of the one-way ejection mode, it is essentially necessary. Excessive ink exceeding the ink amount will be ejected.
[0014]
Further, the above-described dot formation time difference not only changes when switching between the one-way ejection mode and the two-way ejection mode, but also depends on the size (A4, A5, B5, etc.) of the recording medium in the main scanning direction of the recording head. Change. Therefore, even if the size of the recording medium is changed, the magnitude of the blurring effect of the subsequent dots changes.
[0015]
However, in the conventional ink jet recording apparatus, the change in the magnitude of the bleeding effect of the subsequent dots due to the change in the dimensions of the recording medium is not taken into account, and the same weight of ink is applied regardless of the dimensions of the recording medium to be printed. Drops were being ejected. For this reason, there is a case where the ink is ejected excessively or conversely in comparison with the originally required amount of ink.
[0016]
Further, the magnitude of the bleeding effect of the subsequent dots varies depending not only on the above-described dot formation time difference but also on the type of ink and the material of the recording medium. For example, dye ink has a larger bleeding effect than pigment ink, and PM photographic paper has a smaller bleeding effect than plain paper.
[0017]
However, in the conventional ink jet recording apparatus, the change in the magnitude of the bleeding effect of the subsequent dots due to the change in the type of the recording medium is not considered, and the same weight is applied regardless of the type of the recording medium to be printed. Ink droplets were ejected. Also in this case, there is a possibility that ink droplets are ejected excessively or conversely in comparison with the originally required amount of ink.
[0018]
The present invention has been made in consideration of the above-described circumstances, and when performing a desired process by discharging droplets toward an object to be processed, the amount of the liquid is excessively large compared to the amount of liquid originally required. Alternatively, it is an object of the present invention to provide a liquid ejecting apparatus and a control method of the liquid ejecting apparatus, which do not cause the liquid to be excessively discharged.
[0019]
[Means for Solving the Problems]
In order to solve the above problem, a liquid ejecting apparatus according to the present invention is directed to a liquid ejecting a liquid droplet from a nozzle opening toward an object to be processed by causing a pressure fluctuation in a liquid inside a pressure chamber communicating with the nozzle opening. An ejection head, scanning means for changing a relative positional relationship between the object to be processed and the liquid ejection head in order to change a landing position of a droplet on the object, and controlling the liquid ejection head Control means for discharging droplets from the nozzle opening, and the control means includes a control unit configured to control the control unit to control a subsequent dot that at least partially overlaps the preceding dot from a point in time at which the preceding dot is formed on the workpiece. The weight of the liquid ejected from the liquid ejecting head for forming one dot is reduced as the dot formation time difference, which is the time until the dot formation time, is shorter.
[0020]
Further, preferably, the scanning means, a main scanning mechanism for scanning the liquid ejecting head in the main scanning direction, a sub-scanning mechanism for transporting the workpiece in a sub-scanning direction orthogonal to the main scanning direction, The control unit has a one-way ejection mode in which droplets are ejected only in the forward path in the main scanning direction, and a bidirectional ejection mode in which droplets are ejected in both the outward path and the backward path in the main scanning direction. It has a switching function, and the weight of the liquid to be ejected to form one dot is smaller in the bidirectional ejection mode than in the unidirectional ejection mode.
[0021]
Preferably, the control means determines the dot formation time difference based on a size of the object to be processed.
[0022]
Preferably, the control means determines the dot formation time difference based on the weight of the liquid ejected from the liquid ejecting head per unit time per unit area of the workpiece.
[0023]
Preferably, the control means determines the weight of the liquid to be ejected to form one dot in consideration of not only the dot formation time difference but also the type of the liquid to be ejected.
[0024]
Preferably, the liquid ejecting head is capable of selecting and ejecting either a pigment-based ink or a dye-based ink, and the control unit is more capable of ejecting the liquid than a pigment-based ink. In the case of the dye-based ink, the weight of the liquid ejected to form one dot is reduced.
[0025]
Preferably, the control means determines the weight of the liquid to be ejected for forming one dot in consideration of not only the dot formation time difference but also the type of the object to be processed.
[0026]
In order to solve the above-described problems, the present invention provides a liquid ejecting head that causes a pressure change in a liquid inside a pressure chamber communicating with a nozzle opening to discharge droplets from the nozzle opening toward a processing target, Scanning means for changing the relative positional relationship between the object to be processed and the liquid ejecting head in order to change the landing position of the droplet on the object to be processed; and the nozzle for controlling the liquid ejecting head and controlling the nozzle A control unit for discharging liquid droplets from an opening, wherein the control unit controls the liquid ejecting head to form a point in time of forming a preceding dot formed on the workpiece in advance. The liquid ejected from the liquid ejecting head to form one dot is shorter as the dot formation time difference, which is the time until the formation of a subsequent dot at least partially overlapping the preceding dot, is reduced. Characterized in that to reduce the weight.
[0027]
Further, preferably, the scanning means, a main scanning mechanism for scanning the liquid ejecting head in the main scanning direction, a sub-scanning mechanism for transporting the workpiece in a sub-scanning direction orthogonal to the main scanning direction, The control unit has a one-way ejection mode in which droplets are ejected only in the forward path in the main scanning direction, and a bidirectional ejection mode in which droplets are ejected in both the outward path and the backward path in the main scanning direction. It has a switching function, and the weight of the liquid to be ejected to form one dot is smaller in the bidirectional ejection mode than in the unidirectional ejection mode.
[0028]
Preferably, the control means determines the dot formation time difference based on a size of the object to be processed.
[0029]
Preferably, the control means determines the dot formation time difference based on the weight of the liquid ejected from the liquid ejecting head per unit time per unit area of the workpiece.
[0030]
Preferably, the control means determines the weight of the liquid to be ejected to form one dot in consideration of not only the dot formation time difference but also the type of the liquid to be ejected.
[0031]
Preferably, the liquid ejecting head is capable of selecting and ejecting either a pigment-based ink or a dye-based ink, and the control unit is more capable of ejecting the liquid than a pigment-based ink. In the case of the dye-based ink, the weight of the liquid ejected to form one dot is reduced.
[0032]
Preferably, the control means determines the weight of the liquid to be ejected for forming one dot in consideration of not only the dot formation time difference but also the type of the object to be processed.
[0033]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an ink jet recording apparatus and a control method of the liquid ejecting apparatus and the control method of the same according to an embodiment of the present invention will be described with reference to the drawings.
[0034]
FIG. 1 is a perspective view showing a schematic configuration of the ink jet recording apparatus according to the present embodiment. In FIG. 1, reference numeral 1 denotes a carriage. The carriage 1 is guided by a guide member 4 via a timing belt 3 driven by a carriage motor 2, and is reciprocated in the axial direction of a platen 5. I have. The carriage 1, the carriage motor 2, the timing belt 3, and the guide member 4 constitute a carriage mechanism (main scanning mechanism) that scans the inkjet recording head 12 together with the carriage 1 in the main scanning direction.
[0035]
Further, the ink jet recording apparatus includes a feed mechanism (sub-scanning mechanism) that intermittently conveys the recording paper 6 on which recording is performed by the recording head 12 in a sub-scanning direction orthogonal to the main scanning direction.
[0036]
The carriage mechanism and the feed mechanism constitute a scanning unit that changes the relative positional relationship between the recording paper 6 and the recording head 12 during processing in order to change the landing position of the ink droplet on the recording paper 6.
[0037]
The ink jet recording head 12 is mounted on the side of the carriage 1 facing the recording paper 6, and an ink cartridge 7 for supplying ink to the recording head 12 is detachably mounted on the upper part thereof.
[0038]
A cap member 13 is disposed at a home position (right side in FIG. 1), which is a non-printing area of the ink jet recording apparatus. The cap member 13 moves the recording head 12 mounted on the carriage 1 to the home position. Sometimes, the recording head 12 is configured to be pressed against the nozzle forming surface to form a closed space between the recording head 12 and the nozzle forming surface. A pump unit 10 for applying a negative pressure to a closed space formed by the cap member 13 is disposed below the cap member 13.
[0039]
In the vicinity of the printing area side of the cap member 13, a wiping unit 11 having an elastic plate such as rubber is disposed so as to be able to advance and retreat in a horizontal direction with respect to the movement locus of the recording head 12, for example. When reciprocating to the member 13 side, the nozzle forming surface of the recording head 12 can be wiped as necessary.
[0040]
FIG. 2 is a functional block diagram of the ink jet recording apparatus according to the present embodiment. As shown in FIG. 2, the recording apparatus includes a printer controller 61 and a print engine 62. The printer controller 61 includes an interface 63 for receiving print data and the like from a host computer (not shown), a RAM 64 for storing various data, a ROM 65 for storing control routines for various data processing, and a CPU. A control unit (control means) 82, an oscillation circuit 66, a drive signal generation circuit (drive signal generation means) 83 for generating a drive signal, and print data developed into dot pattern data (bitmap data). An interface 67 for transmitting a drive signal and the like to the print engine 62.
[0041]
In addition, the printer controller 61 detachably holds a memory card 76, which is a type of recording medium, and sends a card slot 77 functioning as a recording medium holding unit, and information recorded on the memory card 76 to the control unit 82. And a card interface 78 for transmitting. In the memory card 76, data on the waveform of the drive signal is recorded. As a recording medium other than the memory card 76, for example, a floppy disk, a hard disk, a magneto-optical disk, or the like can be used.
[0042]
The control unit 82 is a type of computer, and controls the ejection of ink droplets with reference to the waveform data of the drive signal recorded on the memory card 76, the control routine recorded on the ROM 65, and the like.
[0043]
The interface 63 receives, for example, any one of character code, graphic function, and image data or print data including a plurality of data from the host computer. Further, the interface 63 can output a busy (BUSY) signal, an acknowledge (ACK) signal, and the like to the host computer.
[0044]
The RAM 64 is used as a reception buffer, an intermediate buffer, an output buffer, a work memory (not shown), and the like. Print data from the host computer is temporarily stored in the reception buffer, intermediate code data is stored in the intermediate buffer, and dot pattern data is developed in the output buffer.
[0045]
The ROM 65 stores various control routines executed by the control unit 82, font data, graphic functions, and the like.
[0046]
Note that the ROM 65 stores a control routine (control program) that is continuously used without being changed. Data that is scheduled to be upgraded or changed, such as data related to the waveform of the drive signal, is recorded in the memory card 76.
[0047]
Further, the control unit 82 controls the drive signal generation circuit 83 based on the data on the waveform of the drive signal read from the memory card 76 to generate a predetermined drive signal according to the print mode or the like.
[0048]
The print engine 62 includes a stepping motor 80 for driving the recording head 12 in the main scanning direction, a paper feed motor 81 for transporting recording paper, and an electric drive system 71 for the recording head 12. The electric drive system 71 of the recording head 12 includes a shift register 72, a latch circuit 73, a level shifter 74, a switch 75, a piezoelectric vibrator 161 and the like. Note that the shift register 72, the latch circuit 73, the level shifter 74, and the switch 75 function as pulse generation means.
[0049]
As the control unit 82, for example, a host computer directly connected to the recording apparatus by itself or one of a large number of computers connected via a network can be used.
[0050]
FIG. 3 shows a main part of a drive circuit of the recording head 12, and the shift register 72, the latch circuit 73, the level shifter 74, the switch 75, and the piezoelectric vibrator 161 in FIG. Elements 72A to N, 73A to N, 74A to N, 75A to N, and 161A to N correspond to the nozzle openings 165 (see FIG. 4). For example, when the bit data applied to each of the switch elements 75A to 75N configured as analog switches is “1”, the drive vibration is directly applied to the piezoelectric vibrators 161A to 161N, and the piezoelectric vibrators 161A to 161N are driven. Deforms according to the signal waveform of the signal. Conversely, when the bit data applied to each of the switch elements 75A-N is "0", the drive signal to each of the piezoelectric vibrators 161A-N is cut off, and each of the piezoelectric vibrators 161A-N holds the previous charge. .
[0051]
FIG. 4 is a sectional view showing the structure of the recording head of the ink jet recording apparatus shown in FIG.
[0052]
The recording head 12 includes a base 163 made of a synthetic resin, and a flow path unit 164 attached to a front surface (corresponding to the left side in the figure) of the base 163. The flow path unit 164 includes a nozzle plate 166 having a nozzle opening 165 formed therein, a vibration plate 167, a flow path forming plate 168, and a sheet 176.
[0053]
The base 163 is a block-shaped member provided with an accommodation space 169 that is open at the front and back. The piezoelectric vibrator 161 fixed to the fixed substrate 170 is accommodated in the accommodation space 169.
[0054]
The nozzle plate 166 is a thin plate-like member having a large number of nozzle openings 165 formed in the sub-scanning direction. Each nozzle opening 165 is opened at a predetermined pitch corresponding to the dot formation density. The vibration plate 167 and the sheet 176 form an island portion 171 as a thick portion with which the piezoelectric vibrator 161 contacts, and a thin portion 172 provided to surround the island portion 171 and having elasticity. .
[0055]
A large number of island portions 171 are provided at a predetermined pitch such that one island portion 171 corresponds to one nozzle opening 165.
[0056]
The flow path forming plate 168 is provided with an opening for forming a pressure chamber 173, a common ink chamber 174, and an ink supply port 175 that connects the pressure chamber 173 and the common ink chamber 174.
[0057]
Then, the nozzle plate 166 is disposed on the front surface of the flow path forming plate 168, and the diaphragm 167 and the sheet 176 are disposed on the back side. The flow path unit 164 is formed integrally by bonding or the like while sandwiching the.
[0058]
In the flow channel unit 164, a pressure chamber 173 is formed on the back side of the nozzle opening 165, and the island portion 171 of the diaphragm 167 is located on the back side of the pressure chamber 173. Further, the pressure chamber 173 and the common ink chamber 174 communicate with each other through an ink supply port 175.
[0059]
The front end of the piezoelectric vibrator 161 is in contact with the island portion 171 from the back side, and the piezoelectric vibrator 161 is fixed to the base 163 in this contact state. In addition, a drive signal (COM), print data (SI), and the like are supplied to the piezoelectric vibrator 161 via a flexible cable.
[0060]
The piezoelectric vibrator 161 in the longitudinal vibration mode has a characteristic that when charged, contracts in a direction perpendicular to the electric field, and when discharged, expands in a direction perpendicular to the electric field. Therefore, in the recording head 12, when charged, the piezoelectric vibrator 161 contracts rearward, and with this contraction, the island portion 171 is pulled back backward, and the contracted pressure chamber 173 expands. With the expansion, the ink in the common ink chamber 174 flows into the pressure chamber 173 through the ink supply port 175. On the other hand, the discharge causes the piezoelectric vibrator 161 to extend forward, the island portion 171 of the elastic plate is pushed forward, and the pressure chamber 173 contracts. With this contraction, the ink pressure in the pressure chamber 173 increases.
[0061]
Then, in the present embodiment, the above-described recording head 12 is controlled by the control unit 82 shown in FIG. 2 as follows.
[0062]
As illustrated in FIG. 5, the control unit 82 determines the dot formation time difference, which is the time from the time when the preceding dot is formed on the recording paper 6 to the time when the subsequent dot at least partially overlapping the preceding dot is formed. The recording head 12 is controlled so that the length of the dot is determined and the weight of the ink ejected from the recording head 12 for forming one dot is reduced as the difference in dot formation is shorter. The weight of ink for forming one dot can be changed by changing the waveform of a drive signal applied to the piezoelectric vibrator 161 of the recording head 12.
[0063]
Note that, for example, when printing is performed on the recording paper 6 in a plurality of passes in the main scanning direction of the recording head 12 as the succeeding dot at least partially overlapping the preceding dot, the preceding dot formed in the preceding pass is A dot formed in a succeeding pass and at least partially overlapping the preceding dot can be given. In this case, the preceding dot and the succeeding dot overlap in the main scanning direction.
[0064]
Also, for example, when the recording paper 6 is fed in the sub-scanning direction at a predetermined pitch after the preceding dot is formed, and the subsequent dot is formed after that, overlapping of the preceding dot and the subsequent dot occurs. . In this case, the preceding dot and the succeeding dot overlap in the sub-scanning direction.
[0065]
The control unit 82 in the present embodiment discharges ink droplets from the recording head 12 only in the forward path in the main scanning direction, and discharges ink droplets from the recording head 12 in both the forward path and the return path in the main scanning direction. It has a function of switching between the bidirectional ejection mode.
[0066]
The above-described dot formation time difference is shorter in the bidirectional ejection mode than in the one-way ejection mode. Therefore, the control unit 82 performs recording so that the weight of ink ejected to form one dot in the bidirectional ejection mode is smaller than the weight of ink ejected to form one dot in the one-way ejection mode. The head 12 is controlled.
[0067]
Further, the control unit 82 considers the size of the recording paper 6 when determining the above-described dot formation time difference. Generally, as the size of the recording paper 6 in the main scanning direction becomes smaller, the above-described dot formation time difference becomes shorter. Therefore, the control unit 82 controls the recording head 12 so that the weight of the ink ejected to form one dot becomes smaller as the size of the recording paper 6 in the main scanning direction becomes smaller.
[0068]
Further, the control unit 82 determines the above-described dot formation time difference based on the total amount of ink ejected from the recording head 12 per unit time with respect to the unit area of the recording paper 6. For example, assuming that the weight of the ejected ink droplets is the same, the fact that the total amount of the ink ejected from the recording head 12 per unit time per unit area is large means that the ink ejected per unit time This means that the number of ejected drops is large. Then, since a large number of ink droplets ejected per unit time means that the ejection interval between ink droplets is short, in this case, it is determined that the above-described dot formation time difference is short, Reduce the weight of the ink drop. As described above, the control unit 82 controls the recording head so that as the total amount of ink ejected from the recording head 12 per unit time per unit area increases, the weight of the ink droplet (the ink weight per dot) decreases. 12 is controlled.
[0069]
The controller 82 preferably adjusts the weight (ink weight per dot) of the ink droplet ejected from the recording head 12 in consideration of not only the above-described dot formation time difference but also the type of ink ejected. I do. The recording head 12 according to the present embodiment can select and eject either the pigment-based ink or the dye-based ink, and the control unit 82 determines that the ejected ink is a dye-based ink rather than a pigment-based ink. In the case of ink, the recording head 12 is controlled so that the weight of ink droplets (ink weight per dot) ejected to form one dot is smaller. This is because the dye-based ink has a larger bleeding effect than the pigment-based ink.
[0070]
The control unit 82 adjusts the weight of the ink droplet ejected from the recording head 12 in consideration of not only the above-described dot formation time difference but also the type of the recording paper 6, and is formed by the ink droplet that lands on the recording paper 6. The weight of the ink ejected to form one dot becomes smaller as the recording paper 6 has a larger dot bleeding effect. In general, since plain paper has a larger bleeding effect than PM photo paper, the control unit 82 discharges one dot when the recording paper 6 is plain paper rather than when it is PM photo paper. The recording head 12 is controlled so that the weight of the ink to be printed is reduced.
[0071]
In the above example, the recording head 12 using the piezoelectric vibrator 161 in the longitudinal vibration mode is used, but a recording head using a piezoelectric vibrator in the flexural vibration mode can be used instead.
[0072]
As described above, according to this embodiment, one dot is formed as the dot formation time difference, which is the time from the formation of the preceding dot to the formation of the succeeding dot (a dot at least partially overlapping the preceding dot), becomes shorter. In this case, the weight of the ink to be ejected is reduced, so that the ink having the optimum weight determined according to the bleeding effect of the subsequent dot can be ejected. Accordingly, it is possible to prevent the ink from being excessively or excessively ejected as compared with the amount of ink that is originally required when performing desired printing. Further, the ink ejection amount can be further optimized by determining the ink weight in consideration of not only the above-described dot formation time difference but also the bleeding effect of the subsequent dots due to the type of recording paper and the type of ink.
[0073]
【The invention's effect】
As described above, according to the present invention, when performing a desired process by ejecting liquid droplets to an object to be processed, the liquid is ejected excessively or excessively small compared to the amount of liquid originally required. Can be prevented.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a schematic configuration of an ink jet recording apparatus according to an embodiment of a liquid ejecting apparatus according to the present invention.
FIG. 2 is a functional block diagram of the ink jet recording apparatus shown in FIG.
FIG. 3 is a circuit diagram showing a main part of a recording head drive circuit of the ink jet recording apparatus shown in FIG.
FIG. 4 is a sectional view showing a structure of a recording head of the ink jet recording apparatus shown in FIG.
FIG. 5 is a view for explaining a method for controlling a print head in the ink jet printing apparatus shown in FIG. 1;
[Explanation of symbols]
1 carriage
2 Carriage motor
3 Timing belt
4 Guide member
6 Recording paper
12 Recording head
82 Control unit
83 Drive signal generation circuit
161 Piezoelectric vibrator
165 nozzle opening
173 pressure chamber

Claims (14)

A liquid ejecting head that causes a pressure change in the liquid inside the pressure chamber communicating with the nozzle opening to discharge droplets from the nozzle opening toward the workpiece;
Scanning means for changing a relative positional relationship between the object to be processed and the liquid ejecting head in order to change a landing position of a droplet on the object to be processed;
Control means for controlling the liquid jet head to discharge droplets from the nozzle openings,
The control means is configured such that the smaller the dot formation time difference that is the time from the formation time of the preceding dot previously formed on the object to the formation time of the subsequent dot at least partially overlapping the preceding dot, the one dot A liquid ejecting apparatus configured to reduce the weight of the liquid ejected from the liquid ejecting head to form the liquid ejecting head. The scanning unit has a main scanning mechanism that scans the liquid ejecting head in the main scanning direction, and a sub-scanning mechanism that conveys the workpiece in a sub-scanning direction orthogonal to the main scanning direction,
The control unit has a function of switching between a one-way ejection mode in which droplets are ejected only in the forward path in the main scanning direction and a bidirectional ejection mode in which droplets are ejected in both the outward path and the backward path in the main scanning direction. The liquid ejecting apparatus according to claim 1, wherein the weight of the liquid ejected to form one dot is smaller in the bidirectional ejection mode than in the one-way ejection mode. The liquid ejecting apparatus according to claim 1, wherein the control unit determines the dot formation time difference based on a size of the processing target. 4. The control device according to claim 1, wherein the control unit determines the dot formation time difference based on a weight of the liquid ejected from the liquid ejecting head per unit time per unit area of the processing target. 5. The liquid ejecting apparatus according to claim 1. 5. The control device according to claim 1, wherein the control unit determines the weight of the liquid to be ejected to form one dot in consideration of not only the dot formation time difference but also the type of the ejected liquid. The liquid ejecting apparatus according to claim 1. The liquid ejecting head is capable of selecting and ejecting either a pigment-based ink or a dye-based ink,
6. The liquid ejecting apparatus according to claim 5, wherein the control unit reduces the weight of the liquid ejected to form one dot when the ejected liquid is a dye-based ink than when the ejected liquid is a pigment-based ink. 7. The controller according to claim 1, wherein the controller determines the weight of the liquid to be ejected to form one dot in consideration of not only the dot formation time difference but also the type of the object to be processed. Liquid ejector. A liquid ejecting head that causes a pressure change in the liquid inside the pressure chamber communicating with the nozzle opening to discharge droplets from the nozzle opening toward the processing target, and changes a landing position of the droplet on the processing target. Scanning means for changing the relative positional relationship between the object to be processed and the liquid ejecting head, and control means for controlling the liquid ejecting head to eject droplets from the nozzle openings. In a control method of a liquid ejecting apparatus provided with:
The control unit controls the liquid ejecting head, and is a dot that is a time from a formation time of a preceding dot previously formed on the workpiece to a formation time of a subsequent dot at least partially overlapping the preceding dot. A method of controlling a liquid ejecting apparatus, comprising: reducing the weight of liquid ejected from the liquid ejecting head in order to form one dot as the difference in forming time is shorter. The scanning unit has a main scanning mechanism that scans the liquid ejecting head in the main scanning direction, and a sub-scanning mechanism that conveys the workpiece in a sub-scanning direction orthogonal to the main scanning direction,
The control unit has a function of switching between a one-way ejection mode in which droplets are ejected only in the forward path in the main scanning direction and a bidirectional ejection mode in which droplets are ejected in both the outward path and the backward path in the main scanning direction. 9. The control method for a liquid ejecting apparatus according to claim 8, wherein the weight of the liquid ejected to form one dot is smaller in the bidirectional ejection mode than in the one-way ejection mode. The method according to claim 8, wherein the control unit determines the dot formation time difference based on a size of the processing target. 11. The dot forming time difference according to claim 8, wherein the control unit determines the dot formation time difference based on a weight of liquid ejected from the liquid ejecting head per unit time with respect to a unit area of the workpiece. The control method of the liquid ejecting apparatus according to the above. 12. The method according to claim 8, wherein the control unit determines the weight of the liquid to be ejected to form one dot in consideration of not only the dot formation time difference but also the type of the liquid to be ejected. The control method of the liquid ejecting apparatus according to the above. The liquid ejecting head is capable of selecting and ejecting either a pigment-based ink or a dye-based ink,
13. The liquid ejecting apparatus according to claim 12, wherein the control unit makes the weight of the liquid ejected to form one dot smaller when the liquid to be ejected is the dye-based ink than when the liquid is the pigment-based ink. Control method. 14. The controller according to claim 8, wherein the controller determines the weight of the liquid to be ejected to form one dot in consideration of not only the dot formation time difference but also the type of the processing target. Control method for a liquid ejecting apparatus.

Images