JP5065460B2 - Recording position adjusting method and ink jet recording apparatus - Google Patents

Description

  The present invention relates to a recording position adjusting method performed by adjusting a driving timing of a recording head, and more specifically, a recording position adjusting method for adjusting a recording position in forward scanning and backward scanning, an inkjet recording apparatus using the method, and an inkjet It relates to a recording system.

  In recent years, relatively inexpensive OA devices such as personal computers and word processors have become widespread, and various output devices such as a recording device that outputs information created by these devices are provided. Among these, recording apparatuses are widespread, and high-speed technology and high-quality technology for the devices are rapidly developed.

  Among these recording apparatuses, serial printers using an ink jet recording method are attracting attention as those that realize high-speed recording or high-quality image recording at low cost.

  In such a serial printer, a technique for performing high-speed recording includes, for example, a bidirectional recording method, and a technique for recording a high-quality image includes, for example, a multipass recording method.

  As a method of increasing the recording speed, a method of performing recording using a recording head having a large number of recording elements is also conceivable, but this leads to an increase in the size of the recording head. As a method for increasing the recording speed without increasing the size of the recording head, as described above, bidirectional recording in which recording is performed by both forward scanning and backward scanning of the recording head is one of effective methods.

  Normally, the recording device does not have a simple proportional relationship due to the time required for paper feed / discharge, etc. However, bidirectional recording has a recording speed approximately twice that of unidirectional recording in which only forward scanning is performed. Obtainable.

  For example, a recording head having a recording density of 360 dpi and having 64 ejection openings arranged in a direction different from the main scanning direction (for example, the sub-scanning direction of the recording medium) is used, and an A4 size recording medium is oriented vertically. When recording is performed, in order to complete an image on the entire recording medium, the recording head needs to perform recording scanning about 60 times. Here, in unidirectional recording, all the recording scans are performed only when moving in one direction from a predetermined scanning start position, and accompanied by non-recording scanning in the reverse direction for returning from the scanning end position to the scanning start position. Therefore, about 60 reciprocating scans are required to complete an image on the entire recording medium under the above-described conditions. On the other hand, in bidirectional recording, recording is performed by both reciprocating scans, so that an image can be completed by 30 reciprocal recording scans of about one half. In this way, since the time required for recording is greatly reduced in bidirectional recording, the recording speed can be improved.

  Next, a multi-pass recording method will be described as an example of a high image quality technology. When recording is performed using a recording head having a plurality of recording elements, the quality of the recorded image largely depends on the performance of the recording head alone. For example, in the case of an ink jet recording head, there are slight differences that occur in the recording head manufacturing process, such as the shape of the ink discharge port and the variation of elements for generating energy used for ink discharge, such as an electrothermal converter, that is, a discharge heater. This affects the amount of ink discharged from each discharge port and the direction of the discharge direction, and can cause image quality deterioration as density unevenness of the finally formed image.

  A specific example will be described with reference to FIGS. In FIG. 10A, reference numeral 901 denotes a recording head. For simplicity, eight nozzles (in this specification, unless otherwise specified, discharge ports or liquid passages communicating therewith and energy used for ink discharge are used. The generated elements are collectively referred to as 902). Reference numeral 903 denotes ink ejected from the nozzle 902 as, for example, a droplet. In general, the ink 903 is ideally ejected from each ejection port in a uniform direction and in a uniform direction as shown in FIG. If such discharge is performed, ink dots having uniform dot sizes land on the recording medium as shown in FIG. 10B, and as a whole, as shown in FIG. 10C. As a result, a uniform image without density unevenness can be obtained.

  However, in practice, the recording head 901 has variations in individual nozzles as described above, and if recording is performed as it is, ink droplets ejected from each nozzle as shown in FIG. As shown in FIG. 11 (B), the size and orientation of the recording medium vary and land on the recording medium. According to the figure, in the head main scanning direction, there is periodically a blank portion where the area factor is less than 100%, or conversely, the dot overlaps more than necessary or is seen in the center. Or white streaks occur. A collection of dots landed in such a state has the density distribution shown in FIG. 11C with respect to the nozzle arrangement direction, and as a result, these phenomena are recognized by the human eye as density unevenness.

  Therefore, a multi-pass recording method has been devised as a countermeasure against this density unevenness. The method will be described with reference to FIGS.

  The recording head 901 is scanned three times as shown in FIG. 12A in order to complete recording in the same area as that shown in FIGS. In the figure, the region in units of 4 pixels, which is half of 8 pixels in the vertical direction, is completed in 2 passes. In this case, the 8 nozzles of the recording head are divided into groups of 4 nozzles in the upper half and 4 nozzles in the lower half in the figure, and the dots formed by one scan in one nozzle are used to store image data in a predetermined image. According to the data sequence, it is thinned out by about half. Then, in the second scan, dots are embedded in the remaining half of the image data to complete a 4-pixel unit region.

  When such a multi-pass printing method is used, even if the print head 901 shown in FIG. 11A is used, the influence on the print image due to the variation of each nozzle is halved. 12 (B), and black stripes and white stripes as shown in FIG. 11 (B) are not so noticeable. Therefore, the density unevenness is considerably relieved as compared with the case of FIG. 11C as shown in FIG.

  When such multi-pass printing is performed, the image data is divided in the first scan and the second scan in such a manner as to make up for each other according to a certain arrangement, that is, a mask. In general, this image data array, that is, a thinning pattern, is most commonly used in an alternating pattern for each vertical and horizontal pixel as shown in FIG. In the unit recording area (here, in units of four pixels), the recording is completed by the first scan in which dots are alternately formed and the second scan in which dots are formed in a pattern opposite to the first scan. Further, the moving amount of the recording medium between each scanning, that is, the sub-scanning amount is normally set to be constant, and in the case of FIGS. 12 and 13, it is moved equally by 4 nozzles.

  Such a multi-pass recording method is particularly effective for recording with a relatively high recording duty such as a solid portion where density unevenness and streaks are easily visually recognized. However, in recording text or ruled lines having a relatively low recording duty, it is difficult to recognize density unevenness and streaks due to the above-mentioned variations, so that there are few merits for performing multi-pass recording. For this reason, when text and ruled lines are recorded, priority is given to speeding up and multi-pass recording is not implemented.

  As another example of the image quality improving technique in the dot matrix printing method, there is a registration adjustment (hereinafter also referred to as “registration adjustment”) technique for adjusting the dot landing position. The registration adjustment is an adjustment method for adjusting the position where dots are formed on the recording medium by shifting the driving timing of the recording head.

  The ink droplets ejected from the nozzles may land out of the intended position due to not only variations in ejection characteristics of individual nozzles but also average head ejection characteristic factors and main body mechanical factors. For example, the distance from the head nozzle to the recording medium (between sheets) varies slightly depending on the individual recording apparatus main body due to manufacturing variations. If the paper spacing is different, the time for the ink droplets ejected from the nozzles to land on the recording medium is different, which causes a landing position shift in bidirectional recording. A difference in ejection speed due to manufacturing variations of the head also causes the same phenomenon.

FIG. 14 shows an example of landing position deviation.
As shown in FIG. 14A, it is ideal to land at the same position on the recording medium in forward scanning and backward scanning, but when the gap between the nozzle and the recording medium is wide, as shown in FIG. Since there is a recording medium below the intersection of both, the landing point is shifted. On the other hand, when the distance between the nozzle and the recording medium is narrow, the landing point is shifted because the recording medium exists before the intersection of both as shown in FIG.

  Further, when the discharge speed is high, as shown in FIG. 14 (d), it will land before both intersect. On the other hand, when the discharge speed is slow, as shown in FIG. As described above, there are various factors for shifting the landing positions of both in the reciprocating recording.

  In addition, when an image is formed with a plurality of rows of nozzles, the landing positions may be shifted due to differences in average ejection characteristics (ejection direction, ejection speed) between the nozzle rows. Since such a deviation in the landing position causes deterioration in image quality, registration adjustment is an indispensable technique for improving image quality.

By the way, registration adjustment is generally performed as follows.
For example, in the reciprocal printing, in the forward and backward scanning landing position alignment, the relative print position conditions in the reciprocating scan are changed on the recording medium for the purpose of adjusting the print timing in the forward scan and the sub scan, respectively. Record ruled lines etc. Whether the inspector can visually check it, select the condition that seems to be in the best position, that is, the condition that is recorded without deviation of the ruled line, etc., and set it by entering it directly into the recording device by key operation etc. Alternatively, the landing position condition is set in the recording apparatus via the application by operating the host computer.

  When recording is performed with a recording head having a plurality of nozzle rows, ruled lines or the like are recorded on the recording medium while changing the relative recording position conditions between the plurality of nozzles. As described above, the user selects the optimum condition that matches the recording position, changes the relative recording position condition, and sets the recording position condition in the recording apparatus for each nozzle row by the same means as described above. To do.

  In such registration adjustment, the adjustment amount is slightly different depending on the recording mode such as the above-described multi-pass printing and non-multi-pass printing. Therefore, a configuration has been proposed in which registration adjustment (recording position deviation adjustment) is corrected every time the recording mode is changed (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 06-127035

  By the way, in recent years, for the purpose of improving the image quality of an ink jet recording apparatus, high definition of ink dots, that is, reduction of ink droplets has been attempted. Accordingly, there is a problem that a slight deviation in landing position, which is not noticeable with a conventional large dot, becomes conspicuous because the dot is small. Accordingly, there is a problem that the phenomenon described below must be considered in addition to the above registration adjustment in the behavior of the recording head ejecting ink.

  The first event is that the landing positions of the main droplet and satellite are different between the forward scan and the backward scan.

  FIG. 15 is a schematic diagram showing the structure of the recording head and the ejected ink droplets.

  For example, in the case of a recording head having a structure that ejects ink by the bubble jet (R) method, bubbles are generated in the ink by the thermal energy from the heater 1401, and ink droplets near the ejection port 1402 are generated in accordance with the generation pressure of the bubbles. Is discharged in a predetermined amount. However, since the liquid-liquid separation in which the ejected ink droplet is separated from the nozzle is unstable, an ink droplet called a satellite 1404 is ejected following the main droplet 1403. The satellite 1404 is formed by separating the rear end portion of the discharged droplet, and has a smaller volume and a lower discharge speed than the main droplet 1403. The satellite 1404 is generated not only by the bubble jet (R) method but also by other piezo methods.

As shown in FIG. 16, the main droplet and the satellite fly in the same direction, but the recording head performs recording while moving in the main scanning direction. Land in position. The landing position displacement distance L between the main droplet and the satellite can be expressed as follows from the main droplet discharge speed V, the satellite discharge speed v, the sheet interval D, and the recording head scanning speed Vp.
L = Vp × (D / v) −Vp × (D / V)
As described above, the main drop 1501 and the satellite 1502 are formed on the recording medium. However, if the satellite dot is sufficiently small with respect to the main drop, only the main drop contributes to the recording. The effects of satellites can be ignored.

  However, as described above, the influence of the satellite cannot be ignored if the main droplet dot becomes smaller due to the smaller ink droplets. That is, the satellite volume is closely related to the ejection characteristics determined by the nozzle shape, etc., and does not become smaller as the main droplet becomes smaller, so the smaller the main droplet dot, the smaller the satellite dot and the main droplet dot. The difference in size tends to be small. Specifically, since the front end of the ejected droplet is the main droplet and the separated part of the rear end is the satellite dot, the characteristics of the ejection port, the characteristics of the ink, specifically the viscosity and surface tension Affects satellite dot size. Therefore, even if the size of the main droplet is reduced, it cannot be said that the size of the satellite dot is reduced in proportion to the size of the droplet. As a result, the effect of satellite dots is relatively increased due to the droplet size reduction, and image forming techniques that take satellites into account have become important.

  For example, a case where a ruled line in the vertical direction (sub-scanning direction) is printed will be described as an example. Here, a description will be given using a head having 304 nozzles arranged at a 600 DPI pitch.

  When recording is performed in both directions, the positional relationship of the satellite dots with respect to the main droplet dots is opposite between forward scanning and backward scanning.

  FIG. 17A is a schematic diagram showing the positions of main droplet dots and satellite dots when bidirectional printing is performed in non-multipass printing. FIG. 17B is a schematic diagram in which one scan is enlarged at the main droplet dots and satellite dots.

  If 1-pass printing, that is, non-multi-pass printing is performed, the forward scan and the backward scan are switched by the width of 304 nozzles (about 13 mm), so that the recording result is obtained by reversing the positions of the satellite dots with a width of about 13 mm.

  FIG. 17C shows the line density of the ruled lines recorded at this time. For example, if the main droplet discharge speed V = 15 m / s, the satellite discharge speed = 10 m / s, the paper gap D = 1.6 mm, and the scanning speed Vp = 25 Inch / s, the deviation L is about 0.03 mm. Since the resolution of the human visual characteristic is low, it is substantially recognized as the line density schematically shown in FIG. In forward scanning and backward scanning, the line density is inverted as shown in FIG. There is little overlap between the two concentrations. Therefore, the ruled line is rattled in the recording result in units of nozzle width. In order to smoothly connect the ruled lines recorded in the forward scanning and the backward scanning, it is necessary to adjust the registration to the position shown in FIG. 18A to maximize the overlap of the line densities of the forward scanning dots and the backward scanning dots.

  On the other hand, when multi-pass printing is performed, the forward direction recording and the backward direction recording are evenly mixed in the neighboring pixels, so that the satellite dots are formed almost equally on the left and right sides of the main droplet dots (FIG. 19). (See (A)). Since the resolution of the visual characteristics is low, the density is substantially recognized as shown in FIG. Therefore, in order to record ruled lines smoothly, it is necessary to adjust the registration so that the main droplet dots are in the same column.

  As described above, when the influence of satellite dots cannot be ignored, there arises a problem that optimum registration adjustment values differ between multipass printing and non-multipass printing. Further, the distance L between the main droplet dots and the satellite dots increases in proportion to the moving speed of the recording head. Therefore, in the form in which the recording head is moved fast for speeding up, the distance L between the main droplet dots and the satellite dots becomes large, and the satellite dots become conspicuous, which becomes more serious.

  Next, as a second event, when there are a plurality of drive modes (for example, a 1200 dpi mode and a 600 dpi mode) with different intervals for ejecting ink, the registration adjusted at the ink discharge timing in one of the drive modes. In the adjustment, when printing is performed in another driving mode, the dot landing position in the forward scanning and the dot landing position in the backward scanning are slightly shifted, and the shift is conspicuous because the dot has a small diameter. It is done.

  Conventionally, when ejecting ink by driving a recording head with a plurality of nozzles arranged, the nozzle group is divided into a plurality of blocks and simultaneously ejected in units of blocks in order to reduce the power capacity required for driving. A technique of block division driving is generally known.

  In this block division driving, the ejection timing of each nozzle when ejecting ink from the nozzle according to the recording data is shown in FIGS. As shown in FIG. 20, for example, the nozzle of a head having 304 nozzles is divided into a plurality of blocks (in this case, 19 blocks), and the ejection order of the nozzles in each block is defined as shown in FIG. 21, and shown in FIG. Discharge is performed at the pulse timing. That is, ink is ejected from the nozzles corresponding to the ejection order 1 of all the blocks at a certain timing, and the nozzles of the ejection order 2 of all the blocks are ejected by shifting the timing by the shift time d. Similarly, the nozzles having the ejection orders 3 to 16 are ejected by sequentially shifting the timing.

  By controlling this block division drive, the number of simultaneous ejections can be reduced, so that it is possible to suppress the instantaneous generation of excessive current compared to the case where all nozzles are driven simultaneously. Become.

  However, in the above method, since the discharge timing is different for each nozzle in the block, the landing position is slightly different for each nozzle. That is, when a ruled line parallel to the nozzle row is recorded under the condition that the CR speed is 15 inches / sec and the shift time d is 3.5 μsec, in practice, as shown in FIG. 23, 1/1200 inch (about 21 μm width). Since this phenomenon may lead to degradation of image quality, this phenomenon reduces the drive timing shift d as much as possible in order to narrow the spread width w shown in FIG. desirable.

  In general, an inkjet printer employs a method in which ink is ejected by applying pressure to ink in a nozzle by foaming due to film boiling on a heater or vibration of a piezo element. The pressure propagates not only in front of the nozzle (ink ejection direction) but also behind the nozzle, that is, in the liquid chamber. The pressure propagated to the liquid chamber also propagates to surrounding nozzles. As a result, the ink of the nozzles present in the vicinity of the ejected nozzle vibrates. If pressure is applied in a state where the ink vibrates, the state in the nozzle is unstable, and normal ejection may not be performed. For this reason, after ejection, it is necessary to perform ejection after pausing only at a timing at which vibration is considered to have subsided. Note that when the number of simultaneous ejections is small, the pressure propagating to the peripheral nozzles is small, so that the ink vibration generated in the nozzles is contained in a relatively short time.

  In multi-pass printing, the number of ejections per scan usually decreases with an increase in the number of passes (the number of scans required to complete an image in a predetermined area). That is, in printing with a large number of passes, the number of simultaneous ejections is relatively small, so that the adverse effects due to the pressure propagation are almost eliminated, and the drive timing shift d can be reduced. On the other hand, in printing with a small number of passes, since the number of simultaneous ejections is relatively large, the above-described adverse effect occurs, and the drive timing shift d must be increased. For this reason, some printers having a plurality of recording modes having different numbers of passes perform printing using a plurality of driving modes having different driving timing shifts d in accordance with the number of passes.

  However, since the dot spread width w differs depending on the drive mode, in the reciprocating recording, when recording is performed using the same reciprocal registration value regardless of the drive mode, there is a problem that the landing position is shifted. This will be described with reference to the drawings.

  FIGS. 24 (A) and 24 (B) are diagrams for explaining a phenomenon in which the landing position is shifted during bidirectional printing due to a difference in driving mode when two-pass printing is performed using a checker pattern mask. It is the figure which represented the upper dot arrangement typically. FIG. 24A shows a drive mode in which the drive timing shift d is set to 3.5 μsec in order to suppress the dot spread width w to 1200 dpi (1/1200 inch) (referred to as 1200 dpi drive mode). The dot arrangement in the first / second scan ejection is shown on the right side and the dot arrangement on the paper surface after recording. Since the scanning direction is reversed between the first scan and the second scan, the ejection order in the block is reversed in the second scan, that is, backward printing.

  FIG. 24B shows a drive mode in which the drive timing shift d is set to 7.0 μsec in order to suppress the dot spread width w to 600 dpi width (1/600 inch) (referred to as 600 dpi drive mode). The dot arrangement in the first and second scan ejections is on the left side, and the dots on the paper surface after recording show the positions on the right side.

  The reciprocal registration value is adjusted so that the landing position is optimal in the 1200 dpi drive mode for both prints.

  In each drive mode, in order to support reciprocal printing, the ejection order in the block is reversed between forward printing scan and backward printing scan.

  As can be seen from FIG. 24 (B), when 600 dpi driving recording is performed with a reciprocal registration value set so that landing is optimal during 1200 dpi driving, the dot spread width differs from that during 1200 dpi driving, so the landing position is optimal. Deviation from position.

  This landing deviation is a level where the influence of the deviation is relatively small and the deterioration of the image quality is not recognized when the dot diameter formed on the medium by ink landing is large. However, as ink droplets have become smaller and the dot diameter has become smaller, the impact of landing deviation has become so large that it cannot be ignored.

  As described above, since the diameter of the dots to be recorded has become smaller as the size of the ejected ink droplets has become smaller, depending on the driving mode such as block division driving, dot landing in forward scanning and backward scanning is possible. There is a problem that the influence of the position shift becomes large and the deterioration of the image quality becomes conspicuous.

  An object of the present invention is to provide an ink jet recording apparatus and a recording position adjusting method capable of recording a high quality image while suppressing deterioration in image quality even when the recording head driving mode is different.

According to the recording position adjusting method of the present invention, a recording head in which a plurality of nozzles for ejecting ink are arranged is reciprocated in a predetermined direction different from the nozzle arrangement direction to record the ink dots on a recording medium. A method for adjusting a recording position in an ink jet recording apparatus, wherein the recording head is scanned once in a predetermined area on the recording medium to complete recording, and the recording head is moved in a predetermined area at the predetermined speed. A determination step for determining an ink ejection timing in the backward scanning relative to an ink ejection timing in the forward scanning of the recording head in each of the multipass printing in which the printing is completed by scanning a plurality of times, and the one-pass printing And a recording step for recording based on the timing determined by the determination step, and the determination step is Wherein determining the ejection timing of ink in the multi-pass printing as forward and main droplet dots of ink ejected by scanning a main droplet dot of ink ejected by the backward scanning are disposed in the same column, the forward scanning The recording position of the main droplet dot of the ink ejected in the backward scanning should be arranged in the same column as the main droplet dot of the ink ejected in the forward scanning with respect to the recording position of the main droplet dot of the ink ejected in Is determined such that the ink ejection timing of the backward scanning in the one-pass printing is determined such that the ink is displaced in the forward scanning direction.

The ink jet recording apparatus of the present invention is an ink jet which records a dot of ink on a recording medium by reciprocally scanning a recording head in which a plurality of nozzles for discharging ink are arranged in a predetermined direction different from the nozzle arrangement direction. A recording apparatus, wherein the recording head is scanned once in a predetermined area on the recording medium to complete recording, and recording is performed by scanning the recording head in the predetermined area a plurality of times at the predetermined speed. And determining means for determining the ink ejection timing in the backward scanning relative to the ink ejection timing in the forward scanning of the recording head in each of the multi-pass recording and the one-pass recording according to the determining step. a recording means for performing recording based on the determined timing, wherein the determining means, the discharge in the forward scanning A main droplet dot of ink ejected by the main droplet dot and the backward scanning of the ink determines the ejection timing of ink in the multi-pass printing to be arranged on the same column are, of ink ejected by the forward scanning The recording position of the main droplet dot of the ink ejected in the backward scan to be arranged in the same column as the main droplet dot of the ink ejected in the forward scan is the direction of the forward scanning with respect to the recording position of the main droplet dot In this case, the ink ejection timing for the backward scanning in the one-pass printing is determined.

According to the above configuration, it is possible to increase the overlap of the line density of the forward scanning dot and the backward scanning dot, to smoothly connect the ruled lines recorded in the forward scanning and the backward scanning, and to record a high-quality image. it can.

It is a perspective view of the state which removed the front cover of the ink-jet recording device which can apply the present invention. FIG. 4 is a perspective view showing details of the head cartridge. FIG. 2 is a schematic cross-sectional view illustrating a schematic configuration of a recording head. It is a block diagram which shows the electric constitution of an inkjet recording device. It is a flowchart which shows registration adjustment. It is a figure which shows the recording pattern for registration adjustment. It is the table | surface which defined the recording system by the combination of a recording mode and a recording medium. 6 is a flowchart illustrating a process for performing fine adjustment of a registration adjustment value from the start to the end of a recording operation. 6 is a flowchart illustrating processing for performing fine adjustment of a registration adjustment value from the start to the end of recording according to the first exemplary embodiment. (A) is a diagram showing ink droplets ejected from the recording head in an ideal size and ejection direction, (B) is a diagram showing dots when landed at an ideal landing position, and (C). It is a figure which shows the recording density in the recording state of (B). (A) is a figure which shows the example of the ink droplet discharged from the recording head in actual recording, (B) is a figure which shows a dot when the ink droplet of (A) lands, (C) It is a figure which shows the recording density in the recording state of (B). (A) is a diagram showing ink droplets ejected from a recording head in multi-pass recording, (B) is a diagram showing dots when the ink droplet of (A) has landed, and (C) is (B) 2) is a diagram showing the recording density in the recording state. It is a schematic diagram which shows multipass recording. (A) is a figure which shows the ideal landing state in the relationship between the scanning of a recording head, and a landing position, (b) is a figure which shows the landing state in case the paper gap of a recording head and a recording medium is wide, ( (c) is a diagram showing a landing state when the paper interval is narrow, (d) is a diagram showing a landing state when the discharge speed is high, and (e) is a diagram showing a landing state when the discharge speed is slow. It is. FIG. 2 is a schematic cross-sectional view showing the vicinity of a nozzle of a recording head. It is a figure which shows a main drop and a satellite drop. (A) is a diagram showing the positional relationship between main droplets and satellite droplets in bidirectional recording and non-multipass recording, (B) is an enlarged view of the backward scanning portion of (A), (C) is a diagram showing a change in line density in (B), (D) is a diagram showing a substantial change in line density, and (E) is a diagram showing a line density in the forward direction and the backward direction. It is. (A) is a diagram showing the positional relationship between main droplets and satellite droplets in the case of non-multi-pass recording in bidirectional recording with registration adjustment, and (B) is a diagram showing line densities in the forward direction and the backward direction. It is. (A) is a figure which shows the positional relationship of the main droplet and satellite droplet of multipass printing, (B) is a figure which shows the line density of (A). It is a schematic diagram which shows the block structure in a nozzle row. It is a schematic diagram which shows the discharge order of the nozzle in 1 block. It is a time chart which shows discharge timing. It is a schematic diagram which shows the landing position for every block. (A) is a schematic diagram showing a recording result in a 1200 dpi driving mode, and (B) is a schematic diagram showing a recording result in a 600 dpi driving mode.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

(overall structure)
FIG. 1 is a schematic perspective view of an ink jet printer to which the present invention can be applied. FIG. 1 shows a state in which the front cover is removed and the inside of the apparatus is exposed.

  1000 is a replaceable head cartridge, and 2 is a carriage unit that detachably holds the ink jet cartridge. Reference numeral 3 denotes a holder for fixing the ink jet cartridge 1000 to the carriage unit 2. When the ink jet cartridge 1000 is mounted in the carriage unit 2 and the cartridge fixing lever 4 is operated, the ink jet cartridge 1000 is interlocked with the carriage unit 2. 2 is pressed. In addition, positioning of the ink jet cartridge 1000 is performed by the press contact, and at the same time, a contact between a required signal transmission electrical contact provided on the carriage unit 2 and an electrical contact on the ink jet cartridge 1 side is performed. Reference numeral 5 denotes a flexible cable for transmitting an electric signal to the carriage unit 2.

A carriage motor 6 serves as a drive source for reciprocating the carriage unit 2 in the main scanning direction, and a carriage belt 7 transmits the driving force to the carriage unit 2. A guide shaft 8 extends in the main scanning direction to support the carriage unit 2 and guide the movement thereof. Reference numeral 9 denotes a transmissive photocoupler attached to the carriage unit 2, and 10 denotes a light shielding plate provided in the vicinity of the carriage home position. When the carriage unit 2 reaches the home position, the light shielding plate 10 transmits light from the photocoupler 9. The carriage home position is detected by blocking the shaft. A home position unit 12 includes a recovery system such as a cap member that caps the front surface of the inkjet head, suction means that sucks the inside of the cap, and a member that wipes the front surface of the head.
Reference numeral 13 denotes a discharge roller for discharging the recording medium, which sandwiches the recording medium in cooperation with a spur roller (not shown) and discharges it outside the apparatus. Reference numeral 14 denotes a line feed unit, which conveys a recording medium by a predetermined amount in the sub operation direction.

(Head configuration)
FIG. 2 is a perspective view showing details of the head cartridge 1000 used in this embodiment.
A replaceable ink tank 15 stores Bk (black) ink, and a replaceable ink tank 16 stores ink of C (cyan), M (magenta), and Y (yellow) colorants. Reference numeral 17 denotes an ink supply port of the ink tank 16 which is connected to the ink cartridge 1 and supplies ink, and 18 denotes an ink supply port of the ink tank 15 similarly. The ink supply ports 17 and 18 are connected to the supply pipe 20 and configured to supply ink to the recording head 21. Reference numeral 19 denotes an electrical contact which is connected to the above-described flexible cable 5 and configured to transmit a signal based on the recording data to the recording head 21.

  Each of the four lines shown on the front surface of the recording head 21 is a nozzle row of ink ejection nozzles that eject ink. From each nozzle row, Bk (black) ink, C (cyan) ink, and M ( Magenta) ink and Y (yellow) ink are ejected.

  In this embodiment, four colors of ink are ejected. However, the present invention is not limited to this, and other colors such as light cyan and light magenta may be ejected.

FIG. 3 is a schematic cross-sectional view showing a schematic configuration of the recording head 21.
Reference numerals 5102, 5104, 5106, and 5108 denote common liquid chambers that receive ink for ejection. The heater boards 4001 and 4002 are formed by anisotropic etching on the back side of the surface formed by the semiconductor process. Each of the liquid path groups corresponding to the heater group is separated or partitioned so as not to mix different color inks. Reference numerals 5102, 5104, 5106, and 5108 correspond to black, cyan, magenta, and yellow inks in order. Reference numerals 5003 and 5005 are components of the discharge heater group, and discharge heater portions disposed on both sides of the common liquid chamber 5102 corresponding to the discharge ports 5004 and 5006 to liquid passages communicating with them. Thus, the nozzle which discharges each ink is comprised from the nozzle of 2 rows. In the present embodiment, the left nozzle row 5004 is referred to as an even nozzle and the right nozzle 5006 is referred to as an odd nozzle as viewed from the front in FIG. The other discharge heater groups also have the same configuration, and the description thereof is omitted.

  Reference numerals 5101, 5103, 5105, and 5107 are formed on the base plate 4000 and constitute a common liquid chamber together with the common liquid chambers 5102, 5104, 5106, and 5108. 5001 and 5002 are orifice plates formed with ink flow paths and nozzles, and are usually formed of heat-resistant resin. P is a recording medium.

  The state of ink ejection will be described by taking the case of black ink as an example. The ink is filled up to the vicinity of the ejection port 5004, and an electrical signal is sent to the ejection heater 5003 when ejecting the ink. The discharge heater 5003 generates heat for a predetermined time and instantaneously generates bubbles in the ink near the heater. Along with the generation pressure of the bubbles, a predetermined amount of ink is ejected as droplets from the ejection port 5004. In this embodiment, such a bubble jet (R) method is used as an ink discharge method. However, the present invention is not limited to this, and a piezo method or the like may be used.

(Electrical configuration)
FIG. 4 is a block diagram showing an electrical configuration of the ink jet recording apparatus.
The ink jet recording apparatus of this embodiment is connected to a host computer, and performs a recording operation according to image data input from the host computer.

  Reference numeral 400 denotes a CPU that controls the entire inkjet recording apparatus. The CPU 400 includes a ROM 401 and a random memory (RAM) 402 as memories. Then, a drive command is sent to each drive unit via the main bus line 405. Further, an image input unit 403 for inputting image data from the host computer is connected to the main bus line 405. The input image data is converted into an ejection signal corresponding to each nozzle of the recording head by the image signal processing unit 404. Furthermore, operations such as operation buttons provided in the recording apparatus are sent to the CPU 400 via the operation unit 406.

  In accordance with an operation signal input to the operation unit 406 and various commands sent from the host computer, the CPU 400 sends a drive command to the control circuit of each drive unit. The control circuit includes the following. The recovery system control circuit 407 controls driving of a recovery system motor 408 that is a power source of members that perform recovery processing such as the blade 409, the cap 410, and the suction pump 411. A head drive control circuit 415 performs drive control of the heater of the recording head 413. A carriage drive control circuit 416 controls scanning of the carriage in the main scanning direction. A paper feed control circuit 417 controls driving of a paper feed related drive member such as a transport roller.

  In this embodiment, the image data is input from the host computer, but may be generated on the ink jet recording apparatus side. In addition, the image signal processing unit 404 converts the discharge signal for each nozzle. However, the present invention is not limited to this, and a form processed into the discharge signal for each nozzle on the host computer side may be input.

(Registration adjustment)
Next, registration adjustment in the ink jet recording apparatus having such a configuration will be described. In this embodiment, first, a registration reference value is determined, and fine adjustment is performed from the reference value every time the mode is switched according to the difference in the recording mode, so that recording can always be performed with the optimum registration tone value. Like that. First, the registration reference value determination will be described.

FIG. 5 is a flowchart showing registration adjustment.
When the user selects registration adjustment by operating the host computer (step 501), a registration adjustment pattern print command is transmitted from the host computer to the recording apparatus. The recording apparatus that has received this registration adjustment pattern print command prints a registration adjustment pattern after performing necessary recovery operations such as suction, wiping, and preliminary discharge (step 502).

FIG. 6 is a diagram showing a registration adjustment pattern.
In the pattern, six adjustment items are printed, and a black even-odd register, a cyan even-odd register, a magenta even-odd register, a black bidirectional register, a cyan bidirectional register, and a black / color inter-column register are adjusted in the order of A to F. It is. Each adjustment item is composed of 11 adjustment patches having different ejection timings.

  The even-odd registrations from A to C are used to correct the landing position deviation, which is the difference between the ejection direction / ejection speed of the even nozzle and the odd nozzle, and only forward scanning and non-multipass printing is performed. The 11 patches have different ejection timings from the ejection of the even nozzle to the ejection of the odd nozzle, and when the ejection direction / velocity of the even nozzle and the odd nozzle are exactly the same, the ejection timing of landing on the same column Is printed as a “0” patch. Further, patches where the odd nozzle landing position is shifted by ± 1 to 5 pixels in 1200 DPI units with reference to the “0” patch are printed above and below the “0” patch. Here, the direction in which the ejection timing of the odd nozzle is delayed is positive, and the direction in which the ejection timing is early is negative. In other words, when shifted in the plus direction, the formation position of the odd nozzle dot with respect to the dot of the even nozzle is shifted to the print head scanning direction side. Each patch is a uniform pattern with a 50% duty.

  The bi-directional registration from D to E corrects landing position misalignment between forward scanning and backward scanning, and is recorded using only even nozzles. The patch is a uniform pattern with a 25% duty, and multi-pass printing is performed bidirectionally using only even nozzles. The eleven patches land on the same column as the forward-scanning recording dots and the backward-scanning recording dots when the ejection timing of the backward scanning is different, the ejection speed = 15 m / s, and the paper interval = 1.6 mm. Is printed as a “0” patch. Further, patches in which the backward scanning recording dots are shifted by ± 1 to 5 pixels in 1200 DPI units with respect to the “0” patch are printed above and below the “0” patch. Here, a direction in which the ejection timing of the backward scanning is delayed is plus, and a direction in which the ejection timing is earlier is minus.

  The black inter-color line registration of F corrects landing position misalignment between the BK nozzle and the color nozzle, and multipass printing is performed in one direction using only even nozzles. The patch is a uniform pattern in which black, cyan, magenta, and yellow have the same duty and a total duty of 25%. The 11 patches have different discharge timings from the discharge of the black nozzle to the discharge of the color nozzle. When the discharge direction / discharge speed of the black nozzle and the color nozzle are exactly the same, the recording dots are placed in the same column. The arrangement timing is printed as a “0” patch. Further, patches where the landing positions of the color nozzles are shifted by ± 1 to 5 pixels in 1200 DPI units with reference to the “0” patch are printed above and below the “0” patch.

  The user visually checks the registered registration adjustment pattern and selects the most uniform patch with the least noise for each adjustment item (step 503). Then, the pattern number of the selected patch is input from the host computer (step 504). The input value is transmitted from the host computer to the recording apparatus main body as a registration adjustment reference value (step 505), and stored in a nonvolatile memory in the recording apparatus (step 506). At this time, the yellow even-odd register is set to the same value as the magenta even-odd register, and the magenta bidirectional register and the yellow bidirectional register are set to the same value as the cyan bidirectional register.

  The registration reference value thus determined is finely adjusted in the following manner in accordance with the selected recording mode in the actual recording operation.

  The ink jet recording apparatus has a plurality of recording modes in order to respond to user requests. Since the recording operation differs depending on the recording mode, depending on the selected recording mode, further fine adjustment from the registration adjustment reference value may be necessary. In the present embodiment, a recording operation in a mode in which the recording method is switched to unidirectional recording, bidirectional recording, or multipass recording according to the recording mode will be described. More specifically, a registration value fine adjustment method for preventing density unevenness caused by different landing positions of satellite dots depending on the recording method will be described.

(Recording operation)
The ink jet recording apparatus of the present embodiment is provided with the following three recording modes according to the image quality of the recording image required by the user. If you want a high-quality image even if the time required for recording is long, use the “clean” mode. If you want to shorten the time required for recording even if the image quality slightly decreases, select the “quick” mode. When obtaining the image quality and the recording speed, the user selects the “standard” mode. This selection operation may be performed on the host computer or may be performed from an operation button provided on the main body of the inkjet recording apparatus.

  Ink jet recording apparatuses use three types of recording methods: unidirectional recording, bidirectional recording, and multipass recording. Even if recording is performed with the same recording method, the recording result varies depending on the type of the recording medium. Therefore, the recording method is determined depending on the combination of the type of the recording medium and the recording mode. Therefore, the user selects and inputs the type of recording medium in addition to the recording mode.

  The CPU determines the recording method according to the recording mode and the type of the recording medium input by the user. The decision is made according to the following table.

FIG. 7 is a table that defines recording methods according to combinations of recording modes and recording media.
In this way, when the recording medium is plain paper, when the “clean” mode is selected, bidirectional recording and a 4-pass multi-pass recording method are used. On the other hand, when the “fast” mode is selected even on the same plain paper, bidirectional printing is performed but single-pass printing is performed, not multi-pass printing.

  Here, in the registration adjustment described above, the correction of the landing position deviation due to the difference between the ejection direction / ejection speed of the even nozzle and the odd nozzle and the correction of the landing position deviation between the forward scanning and the backward scanning are taken into consideration. . However, it is impossible to correct the unevenness of the line density due to the landing positions of the main droplet dots and the satellite dots being reversed in the forward scanning and the backward scanning as described in the problem. Therefore, in the “bidirectional recording and non-multi-pass recording” mode in which the density unevenness due to the satellite dots is conspicuous, fine adjustment in consideration of the landing position of the satellite dots is further required.

  Therefore, in the present embodiment, registration adjustment and fine adjustment of the registration adjustment value are performed according to each recording mode by the following processing routine.

  FIG. 8 is a flowchart showing a process for finely adjusting the registration adjustment value from the start to the end of the recording operation.

  When a recording command is input from the host computer (step 801), the recording mode and the type of recording medium input at the same time are received (step 802), and the recording method is determined from a predetermined relationship. First, it is determined whether the recording method is bidirectional recording or unidirectional recording (step 803). If the recording method is unidirectional recording, the following processing is performed.

(One-way recording)
In the case of unidirectional recording, since the landing position of most satellite dots is on one side of the main droplet dot, fine adjustment of the registration adjustment value relating to the landing position of the satellite dot is not necessary. Therefore, recording is performed only in accordance with the registration adjustment reference value stored in the nonvolatile memory. Specifically, the following processing is executed.

  First, a registration adjustment reference value stored in advance in a nonvolatile memory in the recording apparatus is read (step 804). However, since the unidirectional recording is used, the only registration reference values used are the even / odd registration and the black / color inter-column registration, and the bidirectional registration is not used.

  The registration tone reference value set in the registration tone pattern includes the influence of satellites. However, in the case of unidirectional printing, the positional relationship between the main droplet dots and satellite dots is always the same. Regardless of non-multi-pass printing, the registration adjustment reference value can be used without correction. Therefore, even in the recording method that is “one-way recording and multi-pass recording”, the recording operation is started based on the registration tone reference value read in step 804 without fine adjustment of the registration tone value. .

The recording data sent from the host computer is received (step 805), and the recording operation is performed in accordance with the ejection signal created based on the recording data (step 806). When all the recording data is received and recorded. (Step 807), the recording result is discharged (step 808), and the recording operation is terminated.
On the other hand, if bidirectional recording is performed in step 803, the following processing is performed.

(Bidirectional recording)
In bidirectional recording, satellite dots land on the main droplet dots alternately in forward recording and backward recording. Therefore, in addition to the adjustment according to the registration tone reference value, a fine adjustment in consideration of the landing position of the satellite dot is further required. However, in the case of multi-pass printing, density unevenness due to the landing position of the satellite dots is not noticeable, and this fine adjustment is not necessary. On the other hand, in the case of non-multipass printing, density unevenness due to the landing position of the satellite dots is conspicuous, and this fine adjustment is necessary. Therefore, in the present embodiment, the processing is different between the “bidirectional recording and multipass recording” mode and the “bidirectional recording and non-multipass recording” mode. Specifically, processing is executed by the following routine.

  The registration reference values of the even / odd registration, the bidirectional registration, and the black / color inter-column registration stored in advance in the printing apparatus are read (step 809). Next, it is determined whether or not multi-pass printing is performed (step 810).

  Here, since the registration adjustment reference value of the bi-directional registration set in the registration adjustment pattern is recorded in multi-pass, in the case of multi-pass recording, if the read registration adjustment reference value is used as it is. Good. The recording data is read in the same manner as the one-way recording (step 811), and recording is performed with the registration adjustment reference value (step 812). When all the recording data has been recorded (step 813), the recording result is discharged (step 814), and the recording operation is terminated.

  On the other hand, in the case of non-multipass printing, correction is necessary because the positional relationship between satellite dots and main droplet dots is different. In the case of this embodiment, in non-multipass printing, if the registration adjustment reference value for multipass printing is corrected by “+1”, that is, the landing position of dots formed in the backward direction is increased by one pixel at 1200 DPI. It has been experimentally found that good results are obtained when moved. Therefore, a correction value of “+1” is added to the registration tone reference value (step 815). Then, recording data is received (step 816), and recording is performed with the corrected registration tone value (step 817). When all the recording data has been recorded (step 818), the recording result is discharged (step 819), and the recording operation is terminated.

  The correction value differs depending on the dot size ratio and density ratio of the main droplet dots and satellite dots, the shift amount L between the main droplet dots and satellite dots, and so on, and therefore it is desirable to optimize the correction value according to the application form.

  As described above, by performing recording using different bi-directional registration adjustment values in multipass printing and non-multipass printing, it is possible to obtain a recording result without image deterioration due to satellite dots.

  In the present embodiment, registration adjustment is performed by performing multi-pass printing of a bi-directional registration adjustment patch of a registration tone pattern, and the registration adjustment value is used as it is in multi-pass printing, and the registration adjustment value in non-multi-pass printing. It is set as the form which adds correction to. However, a bidirectional registration adjustment patch having a registration tone pattern may be recorded in a non-multi-pass manner, corrected in multi-pass recording, and used in the non-multi-pass recording.

  Also, when performing multi-pass recording or non-multi-pass recording on a value adjusted by a registration adjustment pattern printed by any recording method, the registration adjustment value is corrected and recorded. Form may be sufficient. In this case, different values are corrected for multipass printing and non-multipass printing.

  Furthermore, it is also possible to record the adjustment patch in both the multi-pass printing and the non-multi-pass printing in the registration adjustment pattern and perform the registration adjustment for each.

  In this embodiment, the registration adjustment pattern is printed and used to make the user adjust the registration. However, the use of a known automatic registration adjustment means does not impair the effect.

  Further, since the shift amount L between the main droplet dots and the satellite dots is proportional to the scanning speed of the recording head, it is desirable to set a correction value for each scanning speed in a recording apparatus having a plurality of scanning speeds.

  In the first embodiment, the registration value fine adjustment for the purpose of preventing density unevenness due to different landing positions of satellite dots depending on the recording method has been described. However, image degradation is caused not only by satellite dots, but also by slight deviations in dot landing positions during forward scanning and backward scanning. This is because the registration value set in accordance with the drive mode of the predetermined recording head is not different in another drive mode. Therefore, in this embodiment, a recording operation for finely adjusting the registration value according to the driving mode of the recording head will be described.

  The overall configuration, head configuration, electrical configuration, and registration adjustment are the same as those in the first embodiment described above, and detailed descriptions thereof are omitted.

(Recording operation)
The ink jet recording apparatus according to the present embodiment is provided with the following three recording modes according to the image quality of the recording image requested by the user. If you want a high-quality image even if the time required for recording is long, use the “clean” mode. If you want to shorten the time required for recording even if the image quality slightly decreases, select the “quick” mode. When obtaining the image quality and the recording speed, the user selects the “standard” mode. This selection operation may be performed on the host computer or may be performed from an operation button provided on the main body of the ink jet recording apparatus.

  Inkjet recording apparatuses use four types of recording methods: 3-pass recording, 4-pass recording, 6-pass recording, and 8-pass recording. Here, in 4-pass printing, 6-pass printing, and 8-pass printing, printing is performed in the 1200 dpi drive mode. In 3-pass printing, since the number of ejections per scan is larger than in other modes, printing is performed in the 600 dpi drive mode.

  Even if recording is performed with the same recording method, the recording result varies depending on the type of the recording medium. Therefore, the recording method is determined depending on the combination of the type of the recording medium and the recording mode. Therefore, the user selects and inputs the type of recording medium in addition to the recording mode.

  The CPU determines the recording method according to the recording mode and the type of the recording medium input by the user. The determination is made according to Table 1.

  FIG. 9 is a flowchart showing processing for finely adjusting the registration adjustment value from the start to the end of the recording operation.

  When a recording command is input from the host computer (step 9001), the recording mode and the type of recording medium input at the same time are received (step 9002), and the recording method such as the number of passes and the driving mode is determined from a predetermined relationship. Determination is made (step 9003). It is determined whether the recording mode is the 600 dpi driving mode or the 1200 dpi driving mode (step 9004). If the recording mode is the 600 dpi driving mode, the following processing is performed.

  The registration reference values of the even / odd registration, the bidirectional registration, and the black / color inter-column registration stored in advance in the printing apparatus are read (step 9005). Here, since the registration adjustment reference value of the bi-directional registration set in the registration adjustment pattern is recorded in the 600 dpi driving mode, the recorded registration adjustment reference value is used as it is when recording in the 600 dpi driving mode. do it.

  The recording data is sequentially read and recording is performed with the registration adjustment reference value (step 9006).

  When all the recording data has been recorded (step 9007), the recording result is discharged (step 9008), and the recording operation is terminated (step 9014).

  On the other hand, in the 1200 dpi drive mode, the dot spread width is different, so correction is necessary. In the case of this implementation system, the difference in dot spread width between the 600 dpi driving mode and the 1200 dpi driving mode is “+1” in 1200 dpi units, so when the registration tone reference value is corrected by “+1”, that is, in the backward direction. A good result can be obtained by moving the landing position of the dot to be moved by one pixel in 1200 dpi increments. Therefore, a correction value of “+1” is added to the registration tone reference value (step 9009). Then, recording data is received (step 9010), and recording is performed with the corrected registration tone value (step 9011). When all the recording data has been recorded (step 9012), the recording result is discharged (step 9013), and the recording operation is ended (step 9014).

  As described above, by performing recording using different bidirectional registration adjustment values in different drive modes, it is possible to correct a difference in landing position due to a difference in drive mode and obtain a recording result without image deterioration. .

  In this embodiment, when the registration tone pattern is printed in the 600 dpi driving mode and recorded in the 600 dpi driving mode, the registration tone value is used as it is, and when the recording is performed in the 1200 dpi driving mode, the registration tone value is corrected. It is said. However, when printing the registration tone pattern in the 1200 dpi drive mode and recording in the 1200 dpi drive mode, the registration tone value is used as it is, and the registration tone value is corrected when recording in the 600 dpi drive mode. Good.

  Note that all the recording modes described in Embodiment 2 perform multipass recording, but the present invention is not limited to this, and multipass recording and non-multipass recording may be mixed. Further, it may be combined with the fine registration adjustment of the first embodiment.

  As described above, by using the present invention, the drive timing adjustment value determination step is performed when the moving pitch in the paper feeding operation is shorter than the pitch of the nozzle array of the recording head and in other cases. Since the adjustment value is made different, in the bi-directional cut recording, the moving pitch is at an appropriate position in both cases where the moving pitch is shorter than the pitch of the nozzle array of the recording head and in other cases. Records will be made. Therefore, in an inkjet recording apparatus having a bidirectional recording mode, a multi-pass recording mode, a non-multi-pass recording mode, and a plurality of recording modes, it is possible to obtain a recording result without any deterioration in recording quality even in the recording mode.

  In addition, even if the ink droplets to be ejected are reduced in size and the satellite droplets become relatively conspicuous, correction according to the landing position of the satellite droplets can always be performed, so image degradation due to the satellite droplets can be reduced. it can.

  Further, even when there are a plurality of drive modes of the recording head, it is possible to perform correction to match the dot landing position at the time of backward scanning with respect to the dot landing position at the time of forward scanning in accordance with the selected driving mode.

1000 Head cartridge 2 Carriage unit 3 Holder 4 Fixing lever 5 Flexible cable 6 Carriage motor 7 Carriage belt 8 Guide shaft 9 Transmission type photocoupler 10 Light blocking plate 12 Suction member 13 Discharge roller 14 Line feed unit

Claims (4)

A recording position adjusting method in an ink jet recording apparatus that records a dot of ink on a recording medium by reciprocally scanning a recording head in which a plurality of nozzles for discharging ink are arranged in a predetermined direction different from the arrangement direction of the nozzles. There,
One-pass recording that completes recording by scanning the recording head once in a predetermined area on the recording medium, and multi-pass recording that completes recording by scanning the recording head in the predetermined area at the predetermined speed a plurality of times. And a determining step for determining an ink ejection timing in the backward scanning relative to an ink ejection timing in the forward scanning of the recording head,
A recording step of performing recording based on the timing determined by the determination step by the one-pass recording;
Have
In the determining step, the ink ejection timing in the multi-pass recording is set so that the main droplet dots of ink ejected in the forward scan and the main droplet dots of ink ejected in the backward scan are arranged in the same column. The main ink droplets ejected in the backward scan should be arranged in the same column as the main droplet dots ejected in the forward scan with respect to the recording position of the main droplet dots ejected in the forward scan. A recording position adjusting method, wherein the ink ejection timing of the backward scanning in the one-pass recording is determined so that the recording position of the droplet dots is shifted in the forward scanning direction. The determining step includes a step of recording a plurality of patterns with different ink ejection timings in forward scanning and backward scanning by the multi-pass recording, and an adjustment value of the multi-pass recording based on a recording result of the plurality of patterns. The method for adjusting a recording position according to claim 1 , further comprising the step of: An inkjet recording apparatus that records a dot of the ink on a recording medium by reciprocally scanning a recording head in which a plurality of nozzles for ejecting ink are arranged in a predetermined direction different from the nozzle arrangement direction,
One-pass recording that completes recording by scanning the recording head once in a predetermined area on the recording medium, and multi-pass recording that completes recording by scanning the recording head in the predetermined area at the predetermined speed a plurality of times. determining means for determining the ejection timing of ink in each of the relative backward scan for the ink ejection timing in the forward scanning of the recording head and,
Recording means for performing recording based on the timing determined in the determination step by the one-pass recording;
Have
The determination means sets the ink discharge timing in the multi-pass printing so that the main droplet dots of ink discharged in the forward scan and the main droplet dots of ink discharged in the backward scan are arranged in the same column. The main ink droplets ejected in the backward scan should be arranged in the same column as the main droplet dots ejected in the forward scan with respect to the recording position of the main droplet dots ejected in the forward scan. An ink jet recording apparatus, wherein the ink ejection timing of the backward scanning in the one-pass recording is determined so that the recording position of the droplet dots is shifted in the forward scanning direction. The determining means records a plurality of patterns with different ink ejection timings in forward scanning and backward scanning by the multi-pass printing, and an adjustment value for the multi-pass printing based on the printing results of the plurality of patterns. The inkjet recording apparatus according to claim 3 , further comprising:

Images