JP2003291323A - Recorder and recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recorder which can record high-quality images by restricting effects of a deviation of a dot forming position between a first half scanning time and a second half scanning time to be small, when dots are formed by the scanning in a first half direction of reciprocation and the scanning in a second half direction of reciprocation of a recording head onto columns including an increased part for raising a recording resolution in a main scanning direction, and a recording method. <P>SOLUTION: In forming dots by the first half scanning and the second half scanning of the recording head onto columns including the increased part for raising the recording resolution in the main scanning direction, dots on the same odd-number column Co are formed by the first half direction scanning and the second half direction scanning of the recording head. Moreover, dots on the same even-number column Ce are formed by the first half direction scanning and the second half direction scanning of the recording head. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention forms dots by a forward scan and a backward scan of a recording head on a column including an increment for improving the recording resolution of the recording head in the main scanning direction. The present invention relates to a recording device and a recording method. The present invention can be applied to a multi-scan method in which dots on the same raster are divided into a plurality of scans of a print head to be formed.

[0002]

2. Description of the Related Art A recording device such as a printer, a copying machine or a facsimile is constructed to record an image consisting of a dot pattern on a recording medium such as paper or a plastic thin plate based on image information. Such a recording device is
Inkjet type, wire dot type,
It can be divided into thermal type, laser beam type, etc.,
Among them, the inkjet type (inkjet recording apparatus) is configured to perform recording by ejecting ink (recording liquid) droplets from an ejection port of a recording head and attaching the droplets to a recording medium. In recent years, a large number of recording devices have been used, and high speed recording, high resolution, high image quality, low noise, etc. are required for these recording devices. As a recording device that meets such a demand, the inkjet recording device as described above can be cited. In this inkjet recording apparatus, non-contact recording is possible by ejecting ink from the recording head, so that an image can be recorded stably on a wide range of recording media.

In an ink jet recording apparatus or the like, it is difficult to increase the size of the recording head, so that a serial type recording apparatus which performs recording by serially scanning the recording head with respect to a recording medium is mainstream. In this serial type recording apparatus, various proposals have been conventionally made to improve the image quality of a recorded image.

For example, the same raster is divided into a plurality of scans for recording to suppress the influence of variations in the performance of each recording element in the recording head, or the joint of recording bands formed each time the recording head scans. Is controlled to be inconspicuous (hereinafter, also referred to as "multi-scan method").

Further, in order to improve the recording resolution in the main scanning direction scanned by the recording head, when recording the same raster by dividing it into a plurality of scans, the positions of the dots formed in each scan are equal to or less than the basic resolution. The control for shifting the distance in the main scanning direction is performed. For example, in order to double the recording resolution in the main scanning direction, the dot formation position is shifted by ½ of the recording resolution between the even scan and the odd scan. When recording is performed when the print head moves in the forward and backward directions in the main scanning direction by adopting a bidirectional recording method to improve the recording speed, the forward scan during forward movement and the backward direction The dot formation position is shifted by half a pixel between the backward scan when moving and the even scan is performed by the forward scan, and the odd scan is performed by the backward scan. As described above, the method of printing the even-numbered column and the odd-numbered column of the print data by separate scanning is also called a “column thinning-out printing method”.

[0006]

However, in such conventional column thinning recording, one of the even column and the odd column is recorded only during the forward scanning, and the other is recorded only during the backward scanning. for that reason,
When a dot formation position is deviated between the forward scan and the backward scan, the density or the like of the recorded image may change significantly in units of columns, and the image quality may be adversely affected.

An object of the present invention is to form dots on the columns including the increment for increasing the recording resolution in the main scanning direction by the forward scanning and the backward scanning of the recording head, and when the dots are formed during the forward scanning. An object of the present invention is to provide a recording apparatus and a recording method capable of recording a high-quality image while suppressing the influence of the deviation in the dot formation position during the backward scanning.

[0008]

A recording apparatus of the present invention uses a recording head capable of forming dots on a recording medium, and performs main scanning by a forward scanning and a backward scanning in the main scanning direction. A printing apparatus for forming dots on a column including a column increase for increasing the printing resolution in the scanning direction, comprising a control means for forming dots on the same column by forward scan and backward scan of the print head. It is characterized by that.

In the recording method of the present invention, a recording head capable of forming dots on a recording medium is used, and the recording resolution in the main scanning direction is determined by the forward scanning and the backward scanning in the main scanning direction of the recording head. In a printing method for forming dots on a column including a column increase for raising, a dot on the same column is formed by a forward scan and a backward scan of the print head.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. The following embodiment is an application example to an inkjet recording apparatus.

First, prior to the description of the embodiments of the present invention,
An example of the basic configuration of the inkjet recording apparatus to which the present invention can be applied will be described with reference to FIGS. (Basic Configuration Example of Inkjet Recording Device) FIG. 15 is a schematic configuration diagram of a main part of an inkjet recording device to which the present invention can be applied.

The chassis M3019 housed in the exterior member of the recording apparatus is composed of a plurality of plate-shaped metal members having a predetermined rigidity and forms the skeleton of the recording apparatus. Hold the mechanism. M3022
Is an automatic feeding unit that automatically feeds a sheet (recording medium) into the main body of the apparatus. M3029 is an automatic feeding unit M3
This is a conveyance unit that guides the papers, which are sent out one by one from 022, to a predetermined recording position and guides the papers from the recording position to the discharge unit M3030. The arrow Y indicates the paper conveyance direction (sub-scanning direction). The paper conveyed to the recording position is
A desired recording is performed by the recording unit. Recovery processing is performed on the recording section by the recovery section M5000. M2015 is the paper interval adjusting lever, M3006 is LF
It is a bearing of the roller M3001.

In the recording unit, the carriage M4001
Are supported by a carriage shaft M4021 so as to be movable in the main scanning direction of arrow X. This carriage M40
An ink jet recording head H1001 (see FIG. 16) capable of ejecting ink is detachably mounted on 01.
The printhead H1001 of this example constitutes a printhead cartridge H1000 together with an ink tank H1900 that stores ink, as shown in FIG. Ink tank H
As 1900, in order to enable high-quality color recording of a photographic tone, for example, ink tanks for black, light cyan, light magenta, cyan, magenta, and yellow are prepared. Each of these ink tanks H1900 is detachable from the recording head H1001.

The recording head H1001 may utilize thermal energy generated from the electrothermal converter as energy for ejecting ink. In that case, the heat of the electrothermal converter causes film boiling in the ink, and the foaming energy at that time allows the ink to be ejected from the ink ejection port.

The recovery unit M5000 includes a recording head H10.
No. 01 is provided with a cap (not shown) that caps the surface on which the ink ejection port is formed. A suction pump capable of introducing a negative pressure into the cap may be connected to the cap. In that case, a negative pressure is introduced into the cap that covers the ink ejection port of the recording head H1001 to suck and discharge the ink from the ink ejection port, so that a good ink ejection state of the recording head 201 is maintained. Recovery processing (also referred to as “suction recovery processing”) can be performed. A recovery process (also referred to as “ejection recovery process”) is performed to maintain a good ink ejection state of the recording head H1001 by ejecting ink that does not contribute to image recording from the ink ejection port toward the inside of the cap. can do.

Further, the carriage M4001 has a structure shown in FIG.
As described above, a carriage cover M4002 for guiding the recording head H1001 to a predetermined mounting position on the carriage M4001 is provided. Furthermore, the carriage M
4001 includes a head set lever M4007 that engages with a tank holder H1500 of the recording head H1001 to set the recording head H1001 at a predetermined mounting position.
Is provided. Headset lever M4007
A headset plate (not shown) that is urged by a spring is provided at an engaging portion that is rotatably provided with respect to a headset lever shaft located above the carriage M4001 and that engages with the recording head H1001. Has been. Due to the spring force, the headset lever M4007 presses the recording head H1001 and presses the carriage M4001.
Attach to.

FIG. 17 is a block diagram of a main PCB (Printed Circuit Board) E0014 which constitutes a control system of the printing apparatus.

In FIG. 17, reference numeral E1001 denotes a CPU, which has a clock generator (CG) E1002 connected to an oscillation circuit E1005, and its output signal E1019 generates a system clock. Also,
The CPU E1001 is R through the control bus E1014.
OM E1004 and ASIC (Application Specif
ic Integrated Circuit) E1006 and controls the ASIC E1006 in accordance with a program stored in the ROM E1004, and also receives an input signal E1017 from the power key E0018, an input signal E1016 from the resume key E0019, and a cover sensor E0022. The cover detection signal E1042 and the head detection signal (HSENS) E1013 are input and the states corresponding to these input signals are detected. Also, CPU
The E1001 drives the buzzer E0021 by the buzzer signal (BUZ) E1018. Furthermore, CPU E1
001 detects the state corresponding to these inputs based on the exhaustion detection signal (INKS) E1011 input to the A / D converter E1003 and the temperature detection signal (TH) E1012 from the thermistor.
In addition, the CPU E1001 controls the inkjet recording apparatus by performing various logical operations and condition determination.

Here, the head detection signal E1013 is a head mounting detection signal input from the recording head cartridge H1000 via the flexible flat cable E0012 (see FIG. 15). In addition, the ink emptyness detection signal E1011 is output from the ink emptyness sensor E.
Analog signal and temperature detection signal E output from 0006
Reference numeral 1012 is an analog signal from a thermistor (not shown) provided on the carriage substrate of the carriage M4001.

E1008 is a CR motor driver,
CR motor control signal E10 from ASIC E1006
Based on 36, a CR motor drive signal E1037 is generated by using a motor power source (VM) E1040 as a drive source to drive the CR motor E0001. E1009
Is an LF / PG motor driver, and ASIC E10
Pulse motor control signal (PM control signal) E1 from 06
Based on 033, the LF motor drive signal E1035 and the PG motor drive signal E1034 are generated using the motor power source E1040 as a drive source. The driving signals E1035 and E1024 drive the LF motor E0002 and the PG motor E0003.

Here, the CR motor E0001 is a drive source for reciprocating the carriage M4001 in the main scanning direction of the arrow X. In the case of this example, as shown in FIG.
The carriage M4001 is reciprocated in the main scanning direction via a belt spanned between the left and right pulleys. LF
Motor E0002 is. By driving the LF roller M3001 (see FIG. 15), the paper is conveyed in the sub-scanning direction of arrow Y. The PG motor E0003 is a recording head H
It is also used as a drive source for the recovery operation of 1001 and the paper feeding operation.

E1010 is a power supply control circuit,
According to the power supply control signal E1024 from C E1006, power supply to each sensor having a light emitting element is controlled. Parallel I / F E0016 is ASIC E1
The parallel I / F signal E1030 from 006 is transmitted to the external parallel I / F cable E1031, and the signal from the parallel I / F cable E1031 is transmitted to the ASIC E
1006. Serial I / F E0017 is
Serial I / F signal E10 from ASIC E1006
28 is transmitted to the external serial I / F cable E1029, and the signal from the cable E1029 is transmitted to the ASIC.
Transmit to E1006.

Head power supply (VH) E1039, motor power supply (VM) E1040, logic power supply (VDD) E10
41 is supplied from the power supply unit E0015. In addition, the power supply unit E0015 is the ASIC E1006.
Based on the head power ON signal (VHON) E1022 and the motor power ON signal (VMOM) E1023 from
ON / OFF of head power supply E1039 and motor power supply E1040
Control OFF. The logic power supply (VDD) E1041 supplied from the power supply unit E0015 is subjected to voltage conversion as necessary, and then supplied to each part inside and outside the main PCB E0014. Also, the head power signal E1039
After being smoothed on the main PCB E0014,
It is sent to the flexible flat cable E0012 and used for driving the recording head cartridge H1000.

Reference numeral E1007 denotes a reset circuit, which detects a decrease in the logic power supply voltage E1041 and detects the CPU E10.
01 and ASIC E1006 reset signal (RES
ET) E1015 is supplied to perform initialization.

The ASIC E1006 is a one-chip semiconductor integrated circuit, and a CPU through the control bus E1014.
It is controlled by E1001 and outputs the above-mentioned CR motor control signal E1036, PM control signal E1033, power supply control signal E1024, head power supply ON signal E1022, motor power supply ON signal E1023 and the like. Also, AS
As described above, the IC E1006 is a parallel I / F.
Signals are exchanged through the E0016 and the serial I / F E0017. Furthermore, ASIC E1006
Is a PE detection signal (PE
S) E1025, ASF from ASF sensor E0009
Detection signal (ASFS) E1026, recording head H100
GAP detection signal (GAPS) E10 from the GAP sensor E0008 for detecting the gap between 1 and the sheet
27, PG detection signal (PG
S) E1032 is input, the state corresponding to those signals is detected, and data indicating the state is sent to the control bus E101.
4 to CPU E1001. Based on the data, the CPU E1001 determines that the LED drive signal E10
38 controls the blinking of LEDE0020.

Here, the PE sensor E0007 is a sensor for detecting the edge of the sheet (sheet edge), the PG sensor E0.
Reference numeral 010 is a sensor for detecting the position of the cap in the recovery unit M5000. In addition, LED E002
0 lights up when the power key E0018 is pressed to inform the operator that recording is possible. Also LED
By changing the blinking method and color of E0020 and sounding the buzzer E0021, it is possible to notify the operator of a trouble of the recording apparatus. When the trouble or the like is solved, the resume key E0019 can be pressed to restart the recording.

Further, the ASIC E1006 generates a timing signal based on the encoder signal (ENC) E1020, and controls the recording operation while interfacing with the recording head cartridge H1000 by the head control signal E1021. Encoder signal (EN
C) E1020 is a flexible flat cable E0
CR encoder sensor E00 input through 012
The output signal of 04. The CR encoder sensor E0
004 outputs an encoder signal E1020 (pulse signal) along with the movement of the carriage M4001, and the moving position of the carriage M4001 can be detected from the signal. Also, the head control signal E1021
Is supplied to the recording head H1000 via a flexible flat cable E0012 or the like.

When printing is performed by the ink jet printing apparatus having the above-mentioned structure, first, the print data sent from the external I / F is temporarily stored in the print buffer in the ASIC E1006. Then, while the CR motor E0001 moves the recording head H1001 together with the carriage M4001 in the main scanning direction, the recording operation of ejecting ink from the recording head H1001 based on the recording data, and the LF motor E0002 conveys the paper in the sub-scanning direction by a predetermined amount. By repeating the carrying operation, the images are sequentially recorded on the paper.

(First Embodiment) FIGS. 1 to 11 are views for explaining a first embodiment of the present invention applicable to the above-described ink jet recording apparatus.

In the following, "column thinning-out recording method"
And "relationship between dot arrangement and density change" and "recording method according to the present invention".

"Column thinning-out recording system" In an ink jet recording apparatus, there is a concern that throughput may decrease as the image resolution increases and the recording density increases. As measures against this, in addition to the column thinning recording method, there have been proposed an inkjet recording head having multiple nozzles, an improved ink ejection frequency, a bidirectional recording method, and the like. The bidirectional recording method, as described above,
In order to improve the printing speed, printing is performed during forward scanning and backward scanning of the recording head in the main scanning direction.

Generally, in a serial scan type ink jet recording apparatus, when ink is ejected from the recording head while moving the carriage on which the recording head is mounted in the main scanning direction, the moving speed of the carriage is the ink from the recording head. Is defined by the discharge frequency and the basic resolution. In the case of the column thinning printing method, in order to increase the printing speed, a speed higher than the speed defined by the ink ejection frequency and the basic resolution is set as the carriage moving speed. Then, printing is performed so that the portion that could not be printed by the previous scan is complemented by the next scan. That is, the recording resolution in the main scanning direction is increased. When the dots on the same raster are recorded by being divided into a plurality of scans, they are also referred to as a multi-scan method as described above.

FIG. 1 is an explanatory diagram of a two-pass bidirectional column thinning-out recording system as an example of the column thinning-out recording system.

In FIG. 1, an arrow X is a main scanning direction in which a carriage having a recording head mounted thereon reciprocates, and an arrow X1 is a forward direction of the first pass and an arrow X2 is a backward direction of the second pass. The arrow Y is the sub-scanning direction in which the paper (recording medium) is conveyed. A black circle basic grid point P1 in FIG. 1 is the position of an ink dot formed during the forward scan of the first pass of the print head, and a white circle basic grid point P2 in FIG. This is the position of the ink dot formed during the backward scan of the second pass. The print head is formed with nozzle rows that are arranged along the sub-scanning direction Y, and ink can be ejected from each nozzle.

In this example, the carriage moving speed is set to the normal 2 because of the 2-pass bidirectional column thinning recording method.
Double, and the drive frequency of the recording head (ink ejection frequency) is set to the same as usual. Then, first, ink dots are formed at the grid points P1 by the forward scan of the first pass of the print head, and then the paper is conveyed in the sub-scanning direction by half the length of the nozzle row in the print head. Then, by the backward scan of the second pass of the print head, ink dots are formed and complemented at the positions of the unprinted grid points P2. Therefore, the same raster is recorded by being divided into a plurality of scans. By repeating such recording operation, without reducing the recording speed,
The resolution in the main scanning direction can be improved.

[Relationship Between Dot Arrangement and Density Change] FIG. 2 is an explanatory diagram of an example of an ink jet recording head. In the recording head 10 of this example, the plurality of ink ejection ports 11 that form the nozzles are formed of two nozzle rows L1 and L2.
Formed on. In each of the nozzle rows L1 and L2, the ejection ports 11 are formed for 128 nozzles at an interval Py corresponding to a recording density of 600 dpi. Also,
The discharge ports 11 in the nozzle rows L1 and L2 are 1200d
They are offset from each other by an interval (Py / 2) corresponding to the recording density of pi. By using such a recording head 10, 1200 dp in the sub-scanning direction of arrow Y
Images can be recorded at a dot density of i. For example, a plurality of the recording heads 10 may be combined as shown in FIG. 3, and different kinds of ink may be ejected from the respective recording heads 10. In that case, a color image can be recorded by ejecting black, light cyan, light magenta, cyan, magenta, and yellow inks from the respective recording heads 10. In addition, the recording head 10 of this example has the ejection port 1 as shown in FIG.
An ink flow path 13 is formed between 1 and the common liquid chamber 12,
An electrothermal converter (heater) 14 is provided in the ink flow path 13. Then, the heat generated by the heater 14 causes bubbling in the ink, and the bubbling energy allows the ink droplets to be ejected from the ejection port 11.

Ink ejection frequency f [Hz] and arrow X
Carriage moving speed Vc [in
ch / S] and Vc = f / 1200.
As a result, an image can be recorded with a dot density of 1200 dpi even in the main scanning direction. Therefore,
As shown in FIG. 5, the recording apparatus using the recording head 10 of this example forms dots at 1200 dpi square lattice points P on a sheet, and has a resolution of 1200 dpi in the main scanning direction and 1200 dpi in the sub scanning direction (1200 × 1200d
pi recording mode) can be realized. The grid points P correspond to those in which the distance between the basic grid points in FIG. 1 is approximately 20 μm. In addition, the size of the ink dot D recorded on the paper by using the recording head 10 varies depending on the type of ink or the recording medium. In this example, the diameter of the dot D is 40 to 50 μm.

The recording resolution in the main scanning direction is 240.
It can be increased to 0 dpi. That is, 1, 3,
During forward scanning of odd-numbered passes of 5, 7, ...
2,400 dpi, which is half the distance between the basic lattices during the backward scanning of the even-numbered passes of 6, 8, ...
By only shifting the dot formation position in the main scanning direction, the recording resolution in the main scanning direction can be set to 2400 dpi. As a result, the main scanning direction is 2400 dpi,
Resolution of 1200 dpi in the sub-scanning direction (2400 x 12
A recording mode of 00 dpi) can be realized. In order to reduce the print data, if the input resolution of the print data input to the printing apparatus is 600 × 600 dpi, then in the print mode of 2400 × 1200 dpi, the print data is stored in the area of (4 pixels × 2 pixels). Represent (4 pixels × 2 pixels) is an area corresponding to 4 pixels in the main scanning direction and 2 pixels in the sub-scanning direction, and represents 9 gradations from levels 0 to 9 as shown in FIG. In levels 2 and 6, two dot arrangement patterns can be set and those patterns can be selectively used. Also,
In levels 1, 3, 5, and 7, four dot arrangement patterns can be set and those patterns can be selectively used. In FIG. 6, Ro is an odd raster,
Re is an even raster, Co is an odd column, and Ce is an even column, and dots are formed at grid points where these intersect.

When recording an image, for example, when the even-numbered column Ce is always printed by the forward scanning and the odd-numbered column Co is always printed by the backward scanning, between the forward scanning and the backward scanning. The adverse effect due to the deviation of the dot formation position in 1) appears strongly.

Hereinafter, as a comparative example of the present invention, FIG.
Dots D1 and D3 of the even column Ce in the level 1 of
Will be described by the forward scan, and the dots D2, D4 of the odd-numbered column Co will be surely printed by the backward scan.

FIG. 7 shows 4 in level 1 of FIG. 6 (a).
This is an example of using one dot arrangement pattern, and four dot arrangement patterns are used so that dots D1, D2, D3, D4 are repeatedly formed in the raster direction. Figure 8
FIG. 8 is an explanatory diagram of a case where dots D1, D2, D3 and D4 in FIG. 7 are recorded in a (2400 × 1200 dpi) recording mode.

In FIG. 9, the formation positions of the dots D1 and D3 of the odd-numbered column Co in the backward scanning are shown on the left side of FIG. 8 with respect to the formation positions of the dots D2 and D4 of the even-numbered column Ce in the forward scanning. It is explanatory drawing at the time of shifting by 1 pixel for every (-direction). That is, FIG. 9A shows the recording result when there is no deviation, and FIGS. 9B to 9I show the formation positions of the dots D1 and D3 of the odd-numbered column Co with respect to the formation positions of the dots D2 and D4. FIG. 9 is an explanatory diagram of a recording result when is shifted by −1 to −8 pixels. On the other hand, in FIG. 10, the formation positions of the dots D1 and D3 of the odd-numbered column Co in the backward scanning are set to the right side in FIG. 8 with respect to the formation positions of the dots D2 and D4 of the even-numbered column Ce in the forward scanning. + Direction)
It is explanatory drawing at the time of shifting 1 pixel at a time. That is,
FIG. 10A shows a recording result when there is no deviation, and FIG.
0 (b) to (i) are print results when the formation positions of the dots D1 and D3 of the odd-numbered column Co are deviated by +1 to +8 pixels from the formation positions of the dots D2 and D4.

As is clear from the recording results of FIGS. 9 and 10, the formation positions of dots 1 and D3 in the backward scan are in the − direction and the + direction with respect to the formation positions of dots D2 and D4 in the forward scan. When there is a deviation, the deviation amount is −
The dot coverage with respect to the surface of the paper largely changes with a period of 8 pixels in the positive and negative directions. Such a large change in coverage causes a change in recording density, which is not desirable in recording a high-quality image.

As described above, in this comparative example, when the dot thinning printing is carried out by shifting the dot formation position by a half pixel during the forward scanning and the backward scanning, FIG.
By using the four dot arrangement pattern at level 1 in (a), one of the even-numbered column printing and the odd-numbered column printing is fixed only during the forward scan of the odd-numbered pass, and the other printing is fixed in the backward direction of the even-numbered pass. It was fixed only during scanning. In this comparative example, as described above, the influence of the deviation of the dot formation position between the forward scan and the backward scan becomes large.

[Recording Method According to the Present Invention] In the above-described comparative example, as shown in FIG. 11A, the odd-numbered column Co is recorded only by the forward scanning and the even-numbered column Ce is recorded only by the backward scanning. . In the present invention, it is avoided that one of the even-numbered column printing and the odd-numbered column recording is fixed during the forward scanning of the odd-numbered pass, and the other recording is fixed during the backward scanning of the even-numbered pass.

In this embodiment, when column thinning recording is performed to improve the resolution in the main scanning direction, the same column is used for the forward scanning of the odd-numbered passes and the even-numbered passes as shown in FIG. 11B. The recording is performed by both the backward scanning of. As a result, the influence of the deviation of the dot formation position between the forward scan and the backward scan is mitigated.

FIG. 12A is an explanatory view when the above-described comparative example is adopted in the 8-pass printing method, and FIG. 12B is a description when the embodiment of the present invention is adopted in the 8-pass printing method. It is a figure.

In the case of the comparative example of FIG. 12A, the odd-numbered columns are recorded only by the forward scan of the odd-numbered passes of 1, 3, 5, 7 and the even-numbered columns are 2, 4, 6, 8 It is recorded only by the backward scan of the even-numbered pass of. 12
In the case of the present embodiment of (b), the odd-numbered columns are printed by the forward scanning of the odd-numbered passes of 1,5 and the backward scanning of the even-numbered passes of 2,6. , 7
Printing is performed by the forward scan of the odd-numbered passes of 4 and the backward scan of the even-numbered passes of 4, 8.

In the present example, the odd columns are 1,
Recorded in the 2nd, 5th, 6th passes, and set the even columns to 3, 4,
It was recorded on the 7th and 8th passes. However, any combination may be used as long as it can allocate the respective columns to the odd-numbered passes and the even-numbered passes, and the combination is arbitrary and is not specified only in the above-described embodiment.

Needless to say, the present invention is not limited to such an 8-pass printing method and can be carried out in other printing modes.

(Second Embodiment) In the above-described embodiment, the column thinning printing is performed by shifting the dot formation position by half a pixel between the odd pass and the even pass.

In this embodiment, in one pass,
By shifting the dot formation position for each nozzle, the same column is printed by forward scanning and backward scanning. That is, as shown in FIG. 13, the odd columns are printed by using the upper half nozzles of the print head 10 in the same figure, and the even columns are printed by using the lower half nozzles of the print head 10 in the same figure. .

The allocation form of the nozzles for printing odd columns and the nozzles for printing even columns is not limited to half as shown in FIG. For example, in FIG.
As in (a) or (b), another example of the allocation form of those nozzles is shown.

(Other Embodiments) In order to perform column thinning printing, it is not always necessary to dispose a plurality of rows of nozzles in a staggered manner as shown in FIG. 2, and it is necessary to dispose a plurality of rows of nozzles in a recording head. Nor.

[0055]

As described above, according to the present invention, when dots are formed by the forward scan and the backward scan of the print head on the column including the increment for increasing the print resolution in the main scan direction. Further, by forming dots on the same column by the forward scanning and the backward scanning of the recording head, the influence of the deviation in the dot forming positions during the forward scanning and the backward scanning can be suppressed to a high level, and high quality can be achieved. Images can be recorded.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a 2-pass bidirectional column thinning-out printing method.

FIG. 2 is an explanatory diagram of an example of an inkjet recording head.

FIG. 3 is an explanatory diagram of a combined use example of the inkjet recording heads of FIG.

FIG. 4 is an enlarged cross-sectional view taken along the line IV-IV of FIG.

FIG. 5 is an explanatory diagram of an example of recording resolution on a sheet.

6A to 6H are explanatory views of an example of a dot arrangement pattern corresponding to levels 1 to 8 of image data.

FIG. 7 is an explanatory diagram of a usage example of a dot arrangement pattern in level 1 of FIG.

FIG. 8 is an explanatory diagram of dots recorded according to a usage example of the dot arrangement pattern in FIG.

9A to 9I are explanatory diagrams of the positional deviation of dots in the minus direction in the level 1 recording area of FIG. 6A.

FIGS. 10A to 10I are explanatory diagrams of misregistration of dots in the plus direction in the level 1 recording area of FIG. 6A.

11A is a schematic explanatory view of a recording form according to a comparative example, and FIG. 11B is a schematic explanatory view of a recording form according to the present invention.

12A is an explanatory diagram of an 8-pass printing method according to a comparative example of FIG. 11A, and FIG. 12B is an explanatory diagram of an 8-pass printing method according to the first embodiment of the present invention.

FIG. 13 is an explanatory diagram of an 8-pass printing method according to the second embodiment of the present invention.

FIGS. 14A and 14B are explanatory diagrams of different modified examples of the 8-pass printing method according to the second embodiment of the present invention.

FIG. 15 is a perspective view of a main part of an inkjet recording apparatus to which the present invention can be applied.

16 is a perspective view of a recording head used in the inkjet recording apparatus of FIG.

17 is a block configuration diagram of a control system of the inkjet recording apparatus of FIG.

[Explanation of symbols]

10 recording head 11 outlet 12 common station room 13 ink flow path 14 Heater (electrical heat converter) D1, D2, D3, D4 dots Co odd column Ce even column Ro odd raster Re even raster

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takayuki Ogasawara             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Tetsuya Eedura             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Mitsuhiko Masuyama             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Akiko Maru             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Daisaku Ide             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Hiroshi Taka             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation F-term (reference) 2C056 EA06 EA08 EC12 EC34 EC69                       EC71 EC74 EC78 EC80 FA11                 2C062 LA01

Claims (9)

[Claims] 1. A column increase for increasing recording resolution in the main scanning direction by using a recording head capable of forming dots on a recording medium and performing forward scanning and backward scanning in the main scanning direction of the recording head. A printing apparatus for forming dots on a column including a minute, comprising a control means for forming dots on the same column by forward scanning and backward scanning of the printing head. 2. The recording according to claim 1, wherein the control unit forms dots on the same column by the forward scan and the backward scan of the print head that are continuous at least once. apparatus. 3. The recording head is provided with a plurality of recording elements capable of forming dots on the recording medium, and the control means is a part of the plurality of recording elements during forward scanning of the recording head. 2. The recording apparatus according to claim 1, wherein a dot on the same column is formed by: and another part of the plurality of recording elements at the time of backward scanning of the recording head. 4. The recording apparatus according to claim 1, wherein the control unit forms dots on the same raster by scanning the recording head a plurality of times. 5. The recording according to claim 1, wherein the recording head has a plurality of recording elements capable of forming dots on the recording medium arranged in a plurality of rows. apparatus. 6. The recording apparatus according to claim 1, further comprising a conveying unit that conveys the recording medium in a sub-scanning direction intersecting with the main scanning direction. 7. The recording apparatus according to claim 1, wherein the recording head is an inkjet recording head capable of ejecting ink. 8. The recording apparatus according to claim 7, wherein the inkjet recording head includes an electrothermal converter that generates thermal energy used for ejecting ink. 9. A column increase for increasing recording resolution in the main scanning direction by using a recording head capable of forming dots on a recording medium and performing forward scanning and backward scanning in the main scanning direction of the recording head. A printing method for forming dots on a column including a minute, wherein dots on the same column are formed by forward scan and backward scan of the print head.