JPH06198916A - Ink jet recording method and apparatus - Google Patents

Abstract

PURPOSE:To record a high-grade image by suppressing the density irregularity of a recorded image. CONSTITUTION:In an ink jet recording apparatus performing recording by emitting ink to a medium to be recorded, when a plurality of recording heads 30-33 respectively have a plurality of nozzles and the numbers of the nozzles of the recording heads are different, the predetermined nozzles of the recording head 33 is used corresponding to the number of the nozzles of the recording head having the least number of nozzles to perform recording.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording method and apparatus for recording by ejecting ink onto a recording medium by a plurality of recording heads.

[0002]

2. Description of the Related Art A conventional ink ejection control will be described below by taking an ink jet recording apparatus for recording by an ink jet method as an example.

The ink jet head (recording head) has a nozzle group for ejecting yellow (Y), magenta (M), cyan (C), and black (Bk), and the number of color nozzles is greater than the number of black nozzles. If it is large, or if the vertical length of the black nozzle group is greater than or equal to the vertical length of the font data, or if the vertical length of the color nozzle group is greater than or equal to the vertical length of the font data. Consider a case.
When performing color recording using such a recording head, the recording head is reciprocated multiple times in the main scanning direction,
Recording is performed using all the nozzles of each head for yellow, magenta, and cyan and only a predetermined nozzle portion of the head for black. Further, when a monochrome image is recorded, ink is ejected onto the recording paper using all the nozzles of the black head for recording.

[0004]

Therefore, conventionally, when recording is performed by such a recording head, when the control shifts from color recording to monochrome recording, it has not been used until then during color recording. A recording operation using nozzles other than the above-mentioned predetermined nozzle portion of the black head is started. For this reason, the nozzles that have not been used until then do not rise well, and there is a risk that unevenness in the ink ejection ink will occur at the start of recording. Such an example is not limited to the above-described color recording switching to monochrome recording,
For example, when the width of the font data exceeds the vertical length of the nozzle group of the print head, when printing such font data in monochrome, the nozzle portion of the black head used for each scan of the print head However, there is a problem that black color unevenness may occur and the quality of the recorded image is deteriorated.

The present invention has been made in view of the above-mentioned conventional example, and an object of the present invention is to provide an ink jet recording method and apparatus capable of recording a high-quality image while suppressing the density unevenness of the recorded image.

[0006]

In order to achieve the above object, the ink jet recording apparatus of the present invention has the following constitution. That is, in an ink jet recording apparatus that ejects ink onto a recording medium to perform recording, when a plurality of recording heads each having a plurality of nozzles and the plurality of recording heads have different numbers of nozzles, the minimum A recording unit for recording by using a predetermined nozzle of another recording head in correspondence with the number of nozzles of the recording head having nozzles.

In order to achieve the above object, the ink jet recording method of the present invention includes the following steps. That is, in an inkjet recording method of recording a color image by ejecting ink from a plurality of recording heads onto a recording medium, when the plurality of recording heads have different numbers of nozzles, the number of nozzles of the recording head having the smallest number of nozzles Correspondingly, a step of recording a color image by using predetermined nozzles of another recording head, a step of recording all nozzles of the recording head for black at the time of recording a monochrome image, And a step of performing preliminary ejection to nozzles that are not the target of use during recording or during recording of a monochrome image.

[0008]

In the above structure, a plurality of recording heads each having a plurality of nozzles are provided, and when the plurality of recording heads have different numbers of nozzles, the number of nozzles of the recording head having the smallest number of nozzles corresponds to the number of nozzles. Then, recording is performed using a predetermined nozzle of another recording head.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 is an external perspective view showing the main structure of the recording section of the ink jet recording apparatus of this embodiment.

In FIG. 1, reference numeral 1 denotes a carriage on which an ink jet head (recording head) 2, a cartridge guide 3, ink cartridges 10, 11 and the like are mounted, and which reciprocates in the arrow F direction along guide shafts 4 and 5. . Reference numeral 6 is a recording paper, which is fed by a paper feed roller 7 in the direction of the arrow G into the main body apparatus, and is fed with a paper feed roller 8 and a pinch roller 12,
It is sandwiched by the paper pressing plate 9 and is sent to the front surface of the recording head 2 in the direction of the arrow H for recording.

The ink cartridge is a color cartridge 10 containing three colors of yellow, magenta and cyan.
And a black cartridge 11 containing only black ink, which are separately inserted into the cartridge guide 3. On the front surface of the recording head 2,
Nozzle groups for yellow, magenta, cyan, and black are arranged in a straight line. The number of nozzles in each nozzle group is N for yellow, magenta, and cyan, and M for black is larger than that for each of the yellow, magenta, and cyan nozzle groups. The interval between the nozzle groups for each color is equal to or greater than the nozzle pitch (see FIG. 3). In this embodiment, it is assumed that there are 24 nozzles for each of yellow, magenta, and cyan, and the number of black nozzles is 64.

FIG. 2 is a view of the recording head unit viewed from the back side with respect to the nozzle ejection port, and FIG. 3 is a view of the recording head unit viewed from the ink ejection port side. FIG. 4 is an enlarged view of FIG.

An ink liquid path for supplying ink from the cartridge to the nozzles is connected to each of the nozzles forming the ink ejection port of the recording head 2.
An ink cartridge for supplying ink is arranged behind the portion where these ink liquid paths are arranged. In an ink liquid path corresponding to each of these nozzles, an electrothermal converter that generates thermal energy for ejecting ink droplets from these nozzles, an electrode wiring for supplying electric power to these electrothermal converters, and the like are provided. It is provided. As a result, when ink is supplied into the ink liquid passage, electricity is supplied to the electrothermal converter according to the image data, and heat is generated in the ink liquid passage. As the ink expands in this way, ink droplets are ejected onto the recording paper 6 such as paper or cloth through each nozzle, and an image corresponding to the image data is recorded on the recording paper, which is a recording medium.

In FIGS. 2 and 3, 101 is a silicon substrate having a driver circuit for driving the electrothermal converter, and 202 is a latch circuit or register for inputting and latching image data (recording data). Both of them are fixed to the aluminum plate 103 by the provided printed circuit board.
The cartridge guide 3 containing the ink cartridges 10 and 11 is inserted substantially parallel to the aluminum plate 103, and is connected to pipes 104 to 107 that also project in parallel to the aluminum plate 103. Each of these pipes 104 to 107 has a silicon substrate 10
1, which is projected from a plastic member 108 called a distributor that spreads in a direction substantially perpendicular to 1.
Further, it is connected to an ink flow path provided inside the distributor 108, and these flow paths are connected to a common liquid chamber.

Here, reference numeral 104 is a yellow pipe, 105 is a magenta pipe, 106 is a cyan pipe, and 107 is a black pipe. In addition, there are four flow paths in the distributor 108 for yellow, magenta, cyan, and black, and each common liquid chamber is connected to each pipe described above. Further, in FIGS. 3 and 4, 3
0 is an inkjet head for yellow with 24 nozzles, 31 is an inkjet head for magenta with 24 nozzles, 32 is an inkjet head for cyan with 24 nozzles, and 33 is black with 64 nozzles. Inkjet head for.

FIG. 5 is a block diagram showing a schematic structure of the ink jet printer of the present embodiment. Parts common to those in the above drawings are designated by the same reference numerals, and their description will be omitted.

In FIG. 5, reference numeral 20 denotes a control unit, which is, for example, a CPU 210 such as a microprocessor, a ROM 21 storing a control program for the CPU 210 and various data.
1. RA used as work area for CPU 210
It is equipped with M213 and the like. Reference numeral 21 denotes a head driver which inputs print data from the control unit 20 and drives the print heads 30 to 33 of respective colors corresponding to the print data. Reference numeral 24 is a carriage motor for driving the carriage 1. 25 is a paper feed motor,
The recording paper 6 is conveyed by rotationally driving the paper feed roller 7, the paper feed roll 8 and the like. Each of 22 and 23 is a motor driver that drives a corresponding motor according to an instruction from the control unit 20. 26 is a recording paper sensor that detects the presence or absence of the recording paper 6, 27 is the presence or absence of an ink cartridge,
And an ink sensor for detecting the remaining amount of ink.

Reference numeral 28 denotes an input unit, which receives print data input from an external device such as a host computer and informs the control unit 20 that the print data has been received.
As a result, the control unit 20 changes the R according to the recording data of each color.
It is stored in any of the buffers 214 to 217 of the AM 213. That is, yellow recording data is input to the yellow buffer 214, magenta data to the magenta buffer 215, cyan data to the cyan buffer 216,
The black data is stored in the black buffer 217, respectively. Here, the data received from the host computer is
The color mode is determined when data of at least two colors among yellow, magenta, cyan, and black are included, and the monochrome mode is determined when only black data is input. The print data thus stored in the buffer corresponding to each color is read in synchronization with the scanning of the carriage 1 in the main scanning direction, and the head driver 2
1, the data corresponding to each of these colors is distributed and output corresponding to each of the yellow head 30, the cyan head 31, the magenta head 32, and the black head 33.

There are two recording modes shown in FIGS. 6 and 7 as the recording operation in the ink jet printer of this embodiment.

FIG. 6 is a schematic diagram showing a state in which color image data having a width of 24 nozzles (dots) is recorded by the ink jet printer of the first embodiment. In this case, 64 nozzles of the black head 33 are used. Of which, 1 to 24
This is shown when printing is performed using the second nozzle.

In FIG. 6, the data portion corresponding to each head is shown, which indicates that there is data to be recorded using each head. In the yellow head 30 to the cyan head 32, printing is performed using all the nozzles (24) in synchronization with the scanning of the carriage 1 in the main scanning direction. The recording paper 6 is conveyed by 24 nozzles in the sub-scanning direction for each reciprocation of the carriage 1 in the main scanning direction. The distance between the yellow head 30, the magenta head 31, and the cyan head 32 is 8
The distance between the cyan head 32 and the black head 33 is 16 nozzles.

Below, based on the color image data, 60
A process of recording the area indicated by 1 will be described. The number of times shown in the main scanning direction indicates the number of times of scanning of the carriage 1, and every time the carriage 1 makes one reciprocation, the recording paper 6 is conveyed by 24 nozzles in the sub scanning direction.

First, in the first scan of the carriage 1,
As indicated by 610, the black data portion is recorded by using the 24 nozzles from the 1st to the 24th of the black head 33. Next, after the recording paper is moved by 24 dots in the sub-scanning direction, ink is ejected from the 17th nozzle to the 24th nozzle of the cyan head 32 by the second scanning of the carriage 1 to perform recording. Next, in the third scan after transporting the recording paper for 24 nozzles, as shown by 612, 16 times from the first nozzle of the cyan head 32.
Cyan data is recorded using up to the th nozzle.

Similarly, in the fourth scan of the carriage 1, magenta data is recorded using all the nozzles of the magenta head 31, and in the fifth scan, the ninth nozzle of the yellow head 30 is used. The 24th nozzle is used to record yellow data, and finally, in the sixth scan, the first to eighth nozzles of the yellow head 30 record the remaining yellow data.

In this way, the carriage 1 is reciprocated six times in the main scanning direction, whereby the black head 3 is moved.
A color image is recorded in an area 601 of 24 nozzles (dots) of the recording paper 6 by using 3 predetermined nozzles (1st to 24th) and all nozzles of the color recording heads 30 to 32. You can

FIG. 7 is a schematic diagram showing an order in which color image data having a width of 48 nozzles (dots) is recorded in the area 701 of the recording paper in the ink jet printer of the first embodiment.

In the case of FIG. 7, the first to 24th nozzles (all nozzles) of the yellow, magenta and cyan heads 30 to 32 and the 1st to 48th nozzles of the black head 33 are used. The printing is performed by moving the recording paper 6 by 24 nozzle widths in the sub-scanning direction for each reciprocation of the carriage 1 in the main scanning direction.

First, in the first scan of the carriage 1,
The black data portion is recorded using the 1st to 48th nozzles of the black head 33 (710). Next, in the second scan of the carriage 1, cyan data is recorded using the 17th to 24th nozzles of the cyan head 32, and in the next third scan, all the nozzles of the cyan head 32 are used. Then, the cyan data is recorded. Then 4
In the second scan, magenta data is recorded by all the nozzles of the magenta head 31, and cyan data is recorded by using the 1st to 16th nozzles of the cyan head 32. Then, in the fifth scanning of the carriage 1, the yellow data is recorded by the ninth to 24th nozzles of the yellow head 30, and the magenta data is recorded by using all the nozzles of the magenta head 31. Then, in the sixth scanning, the yellow data is printed by all the nozzles of the yellow head 30, and in the final seventh scanning (not shown), the yellow data is printed from the first nozzle of the yellow head 30 to the 8th nozzle.
The yellow data is recorded using the th nozzle.

In these scans of the carriage 1, 1
During the 3rd and 5th scans, the 48th nozzle from the 1st nozzle of the black head is used
The black portion of the image data is recorded in dot units.

As described above, the heads 30 to 32 for each color are moved while the carriage 1 is reciprocated a plurality of times.
It is possible to record a color image by using all the nozzles of No. 1 and the specific nozzles (1st to 48th) of the black head 33.

Next, FIG. 8 is a schematic diagram showing the processing when a monochrome image is recorded in units of 64 nozzles (dots) using all the nozzles of the black head 33.

As is apparent from FIG. 8, in this case, the recording paper 6 is conveyed in the sub-scanning direction by an amount corresponding to the nozzle width of the black head 33 for each reciprocating scan of the carriage 1 for recording. . As a result, all the nozzles of the black head 33 are used at the same ratio.

9 and 10 are flow charts showing the recording process of the first embodiment shown in FIGS. 6 and 7, and the control program for executing this process is stored in the ROM 211.

FIGS. 9 and 10 show the recording processing of the area 601 or 701 shown in FIGS. 6 and 7, and the recording operation to other areas on the recording paper 6 will be described for the sake of simplicity. It is omitted.

First, in step 1, the number of nozzles used by the black head 33 is determined. The number of nozzles may be determined, for example, by the image width of the black data in the data to be printed in the sub-scanning direction, or may be predetermined regardless of the print data. As shown in FIG. 6, when storing in units of 24 nozzles of the black head 33, the process proceeds to step S2, and otherwise, proceeds to step S15 (FIG. 10). In step 2, the carriage motor 24
To drive the carriage 1 in the main scanning direction,
Black data is recorded by the 1st to 24th nozzles of the black head 33. In step S3, carriage return is performed to convey the recording paper 6 by 24 nozzles in the sub-scanning direction. Next, in step S4, cyan data is recorded using the 17th to 24th nozzles of the cyan head 32. At the same time, the black data for the next 24 nozzles is recorded by the black head 33 at the same time. However, the description of the recording operation on other areas of the recording sheet will be omitted.

Next, in step S5, carriage return and recording paper conveyance are performed in the same manner as in step S3, and in step S6, the remaining cyan data is transferred to the cyan head 32 to the 1 position.
Recording is performed using the 1st to 16th nozzles. Then, the carriage return and the recording paper are conveyed again (step S
7) In step S8, magenta data is recorded using all the nozzles of the magenta head 31. Next, in step S9, the carriage return and the conveyance of the recording paper are performed, and in step S10, the yellow data is recorded using the ninth to 24th nozzles of the yellow head 30. Next, in step S11, the carriage return and the conveyance of the recording paper are performed in the same manner as in the above-mentioned step, and in step S12, the yellow data is recorded using the 17th to 24th nozzles of the yellow head 30.

When recording is performed in units of 48 nozzles of the black head 33, the process proceeds to step S15, the black data is recorded using the 48 nozzles of the black head 33, and in step S16, like the above-described step S3 and the like. The carriage return recording paper is conveyed, and cyan data is recorded by the 17th to 24th nozzles of the cyan head 32 in step S17. Next, in step S18, after performing carriage return (recording paper feed), step S
At 19, the cyan data is recorded using all the nozzles of the cyan head 32, and at the same time, the black head 33 records the image of the next 48 nozzles.

Carriage return (recording paper feed) is performed in step S20, and an image is recorded using all the nozzles of the magenta head 31 in step S21. At the same time, the cyan head 32 uses the first to sixteenth nozzles to print cyan. Record the data. Next, a carriage return (recording paper feed) is performed in step S22, and step S23
Then, the image recording is performed by the ninth to 24th nozzles of the yellow head 30 and the image recording is performed by using all the nozzles of the magenta head 32. Then, in step S24, carriage return (recording paper feed) is performed, in step S25, image recording using all nozzles of the yellow head 30 is performed, and after carriage return (recording paper feed) in step S26, the yellow head 30 is recorded in step S27. 1st-8
The remaining yellow data is recorded using the th nozzle.

When the number of nozzles used by the black head 33 is 24 or less, as shown in FIG. 6, when 24 or more and 48 or less, as shown in FIG.
It can be easily understood that the recording control can be basically performed in the same manner as in FIG. 7 also in the above case.

According to the ink jet printer of the first embodiment as described above, recording is performed by fixing the used nozzles of the black head 33 to 24 nozzles or 48 nozzles at the time of color recording. When recording a monochrome image, all the nozzles (64) of the black head 33 are used for recording. As a result, the frequency of use greatly differs between the nozzles used during color recording and during monochrome recording. For example, since the first nozzle to the 48th nozzle of the black head 33 and the 49th nozzle to the 64th nozzle have different usage frequencies, density unevenness occurs at the time of switching from color recording to monochrome recording. There is a risk.

Therefore, in the first embodiment, the control is performed as follows. That is, in the ink jet printer of this embodiment, preliminary ejection control is periodically performed to prevent clogging of the head, sticking of ink, and the like. For example, at the start of recording, at the end of recording, or from the start of recording, for example, 12
Every second, the carriage 1 is moved to the non-recording area to perform the preliminary ejection control. FIG. 11 is a flowchart showing the preliminary ejection control when recording is performed using the 1st to 24th nozzles of the black head 33 at the time of color recording (FIG. 6).

First, in step S31, preliminary ejection data corresponding to each head stored in the ROM 211 is output to the head driver 21, and all nozzles of the yellow head 30, all nozzles of the magenta head 31, and the cyan head 32 are output.
10 ink droplets are ejected to each of all the nozzles and the black head 33 (step S32). In step S33, it is determined whether the current recording mode is the color mode or the monochrome mode. If it is the color mode, the process proceeds to step S34, and if it is the monochrome mode, the process proceeds to step S35. In step S34, the preliminary ejection data of the ROM 211 is output from the 25th nozzle to the 64th nozzle of the black head 33 to eject 10 ink droplets (step S36). At this time,
Preliminary ejection is set not to be performed on all the nozzles of the other yellow head 30, magenta head 31, and cyan head 32.

In the monochrome mode, step S3
5, the preliminary ejection data of the ROM 211 is transferred to the yellow head 3
0, output to the head driver 21 so as to set for all nozzles of the magenta head 31 and the cyan head 32, and in step S36, a heat pulse is sent to the heat converter provided inside each head to generate heat inside the head. By doing so, the ink in the ejection port is expanded and ten ink droplets are ejected.

As described above, the first preliminary ejection is performed by all the nozzles of all heads, and the second preliminary ejection is performed only by the nozzles of the heads not used in the current recording mode. As a result, even if the print image is changed, it is possible to print without ink unevenness.

As shown in FIG. 7, the black head 3
Similarly, in the case of a color mode in which recording is performed using 48 nozzles of No. 3, similarly, preliminary ejection from the 49th nozzle to the 64th nozzle of the black head 33 may be performed in step S34.

FIG. 12 is a flow chart showing a modification of the process of FIG. 11, showing the preliminary ejection operation in each of the color recording modes in this case.

This process is executed after step S32 in FIG. 11, and first checks the current color recording mode in step S37. When recording only the yellow data and the black data, the process proceeds to step S38, and the yellow head 30
Preliminary ejection data is set to all nozzles of the color recording heads other than the above, and preliminary ejection data is set to the 25th to 64th heads of the black head 33. When recording only magenta data and black data, step S3
In step 9, the preliminary ejection data is set to all the nozzles of the color recording heads other than the magenta head 31, and the preliminary ejection data is set to the 25th to 64th heads of the black head 33. Similarly, when recording only cyan data and black data, the process proceeds to step S40, where preliminary ejection data is set to all nozzles of the color recording heads other than the cyan head 32, and the 25th to 64th nozzles of the black head 33 are set. Set preliminary ejection data in the head. When the setting of the preliminary ejection data is completed in this way, step S3
Then, the process advances to step 9 to output 10 ejection pulses to the corresponding head to eject ink.

As described above, according to this embodiment, the nozzles of the black head 33 can be used evenly during color recording and monochrome recording to eliminate the density unevenness of the black image, and the heads used up to that point can be used. It is possible to prevent the image density unevenness due to the rising characteristics of the nozzle, which has not been performed.

Next, a second embodiment of the present invention will be described with reference to FIG.

FIG. 13 is a schematic diagram showing an operation of changing the positions of the 24 nozzles used by the black head 33 at the time of color recording and using all the nozzles (64 nozzles) of the black head 33 evenly. .

When the carriage 1 moves in the main scanning direction,
Recording is performed using all nozzles of the yellow, magenta, and cyan heads, but in the case of the black head 33, ejection is performed by changing 24 of 64 nozzles. Note that the recording paper moves by 24 nozzles in the sub-scanning direction each time the carriage 1 scans. Hereinafter, a case of recording the area 130 will be described.

First, in the first scan of the carriage 1, printing is performed using the 24th nozzle from the 1st nozzle of the black head 33 (131). Next, in the second scan, printing is performed using the 17th to 24th nozzles of the cyan head 32 (132). Next, in the third scanning of the carriage 1, the paper sheet motor 25 is rotated in the reverse direction to return the recording sheet by 24 nozzles, and recording is performed using the 25th nozzle to the 48th nozzle of the black head 33 ( 133). As a result, the black data of the area located next in the sub-scanning direction is recorded.

Next, by scanning the carriage 1 for the fourth time,
Cyan data is recorded using the 1st to 16th nozzles of the cyan head 32 (134), and the paper feed motor 25 is reversed during the fifth scan of the carriage 1 as in the second scan. The recording paper is returned by 24 nozzles in the sub-scanning direction by rotating the same in the direction, and the next area (135) in the sub-scanning direction is recorded by the 41st nozzle to the 64th nozzle of the black head 33.

Next, in the sixth scan of the carriage 1, magenta data is recorded using all nozzles of the magenta head 31 (135), and at the same time, the black head 3
An area 137, which is separated by an integral multiple of the width of 24 nozzles in the sub-scanning direction of the recording paper, is recorded by the first to 24th nozzles of No. In the seventh scan of the carriage 1, recording is performed by the ninth to 24th nozzles of the yellow head 30 (139), and in the eighth scan of the carriage 1, the paper feed motor 25 is rotated in the reverse direction, The recording paper is moved in the direction opposite to the sub-scanning direction, and recording is performed by the 25th to 48th nozzles of the black head 33 (139). Then, by the ninth scan of the carriage 1, recording is performed by the first nozzle to the eighth nozzle of the yellow head 30, and by the tenth scan of the carriage 1, the recording paper is returned to the sub-scan to return to the black head 33 41. Recording is performed from the 64th nozzle to the 64th nozzle (140).

In this way, the carriage 1 can be reciprocated 10 times in the main scanning direction, and the 64 nozzles of the black head 33 can be uniformly used to perform color recording on the recording paper. As a result, it is possible to prevent occurrence of used nozzles and unused nozzles in the black head 33 and prevent density unevenness of the recorded image.

Further, by adding the preliminary ejection control as in the first embodiment described above to such control, it is possible to prevent density unevenness in the recorded image.

As shown in FIG. 14, the case where the nozzle positions used by the black head 33 are changed to uniformly use all the nozzles of the black head 33 when recording a monochrome image will be described below. Here, when the carriage 1 is scanned in the main scanning direction, recording is performed using 48 nozzles out of all 64 nozzles of the black head 33. The recording paper is moved by 24 nozzles in the sub-scanning direction for each scanning of the carriage 1.

First, in the first scan of the carriage 1,
Recording is performed using the 1st to 48th nozzles of the black head 33. Next, in the second scan, printing is performed by the 17th nozzle to the 64th nozzle of the black head 33. Further, in the third scan of the carriage 1, recording is performed by the first to 48th nozzles of the black head 33, and in the fourth scan of the carriage 1, the black head 33 is scanned from the 17th nozzle to the 64th nozzle. Recording with nozzles.

In this way, by reciprocating the carriage 1 four times in the main scanning direction, each of the nozzles (64 nozzles) of the black head 33 is used twice, and the monochrome of 192 raster lines is recorded on the recording paper. Images can be recorded.

As described above, in the case of the monochrome recording of the present embodiment, since the used nozzles of the black head 33 are uniformly recorded, the generation of used nozzles and unused nozzles in the black head 33 is eliminated, and the image density unevenness is eliminated. Can be prevented.

Further, by performing the preliminary ejection control in the first embodiment described above, the image density can be further stabilized.

FIG. 15 is a schematic diagram showing the operation when only the yellow data is not included when a color image is recorded as shown in FIG. 6 using the ink jet head of the first embodiment described above. In the preliminary ejection control in this case, the preliminary ejection to the yellow head 30 is not performed in step S35 of the flowchart of FIG.

FIG. 16 shows the contents of each buffer when recording a color image in the above-mentioned embodiment.
FIG. 7 is a diagram showing the contents of the buffer when recording monochrome data. Here, each of the yellow head 30, the magenta head 31, and the cyan head 32 has N nozzles, and the black head 33 has M nozzles. Next, an inkjet printer according to a third embodiment of the present invention will be described. This ink jet printer has the same configuration as that of the first embodiment described above, but as shown in FIGS. 18 to 20, the shape of the ink jet head is different.

18 to 20, nozzle groups for yellow, magenta, and cyan are arranged in a straight line on the left side of the front surface of the recording head 2a, and a nozzle group for black is arranged in a straight line on the right side thereof. It is located in. The number of nozzles in each head is for yellow, magenta,
Each of the cyan heads has N nozzles, and the black head has M nozzles, which are larger than those of the other heads, and the interval between the heads for each color is equal to or greater than the nozzle pitch. For example, in this embodiment, heads for yellow, magenta, and cyan (30
To 32), the number of each nozzle is 24, and the black head 33
The number of nozzles of a is 88.

In the figure, 201 is a silicon substrate, 20
Reference numeral 2 is a printed circuit board, and 203 is an aluminum plate. Reference numeral 204 is a yellow pipe, 205 is a magenta pipe, 206 is a cyan pipe, and 207 is a black pipe. Reference numeral 208 is a distributor. 20. FIG. 20 is an enlarged view of FIG.

A specific example of the recording operation in the ink jet printer of the third embodiment of the present invention will be shown below.

FIG. 21 is a schematic diagram showing an example of recording a color image in units of 24 nozzles using predetermined nozzles (65th nozzle to 88th nozzle) of the black head 33a. Here, similarly to the above-described schematic diagram, when the carriage 1 moves in the main scanning direction, recording is performed by 24 nozzles of yellow, magenta, cyan, and black heads, and recording paper is printed for each scanning of the carriage 1. Is conveyed by 24 nozzles in the sub-scanning direction for recording.

First, in the first scan of the carriage 1,
Black data is recorded by the 65th to 88th nozzles of the black head 33a (181), and at the same time, cyan data is recorded by all the nozzles of the cyan head 32 (180). Second carriage 1
The recording is performed by the ninth nozzle to the 24th nozzle of the magenta head 32 (182). Next, by scanning the carriage 1 for the third time, the yellow head 3
Recording is performed from the 17th nozzle to the 24th nozzle of No. 0 (183), and at the same time, the magenta head 31
Recording is performed using the eighth nozzle to the eighth nozzle (184). Next, by the fourth reciprocating movement of the carriage 1 in the main scanning direction, recording is performed by the first to 16th nozzles of the yellow head (185).

In this way, by reciprocating the carriage 1 four times in the main scanning direction, 24 rasters of recording paper can be recorded in color.

FIG. 22 is a diagram showing an operation of recording by using 48 nozzles of the black head 33a when recording a color image. Here, when the carriage 1 reciprocates in the main scanning direction, recording is performed using all nozzles of the yellow, magenta, and cyan heads, and recording is performed using the 40th to 88th nozzles of the black head 33a. It is carried out. The recording sheet is moved by 24 nozzles in the sub-scanning direction for each scan of the carriage 1.

In the first scan of the carriage 1, printing is performed using all nozzles of the cyan head 32 (190).
Next, in the second scanning, recording is performed with the ninth to 24th nozzles of the magenta head 31 (191), and at the same time, from the 41st nozzle of the black head 33a to the 8th nozzle.
Recording is performed using the eighth nozzle (192). Next, in the third scanning of the carriage 1, the yellow head 30
Recording is performed with 24 nozzles from the 7th nozzle (193)
At the same time, 8 from the first nozzle of the magenta head 31
Recording is performed by the second nozzle (194). Then, in the fourth scanning, recording is performed by the first to 16th nozzles of the yellow head 30 (195), and at the same time, recording is performed by the 41st to 88th nozzles of the black head 33a ( 196).

In the above example, the first, third, and fifth carriages 1 perform preliminary ejection from the 41st nozzle to the 88th nozzle of the black head 33a in the scanning in the main scanning direction. In this way, by reciprocating the carriage 1 four times in the main scanning direction, a color image can be recorded on 24 rasters of the recording paper 6.

As described above, according to the recording control of this embodiment,
The number of nozzles used by the black head 33a can be changed to 24 or 48 for recording. On the other hand, when recording a monochrome image, all nozzles of the black head 33a are used for recording.

By the way, also in the ink jet printer of the second embodiment, similarly to the printer of the first embodiment, the preliminary ejection control is periodically performed in order to prevent clogging of the recording head, ink sticking and the like. Is going. This process is shown in FIG.
In the flowchart of FIG. 1, the preliminary ejection data setting in step S34 can be realized by setting the 25th nozzle to the 88th nozzle of the block head 33a, and thus detailed description thereof will be omitted.

By performing such preliminary discharge control, it is possible to eliminate recording unevenness and print a high-quality image.

As described above, according to the third embodiment, the frequency of use of the nozzles of the black head 33a can be made uniform in both color recording and monochrome image recording.
It is possible to prevent the occurrence of image unevenness due to image recording by nozzles that have not been used until then.

FIG. 23 is a schematic diagram showing an operation when recording black data in 88 raster units using the recording head 2a of the third embodiment and 88 nozzles of the black head 33a. Here, for each reciprocating scan of the carriage 1,
The recording paper is conveyed by 88 nozzles in the sub-scanning direction for recording. Since this processing can be realized in the same manner as the above-mentioned embodiment, detailed description thereof will be omitted.

24 and 25, heads having the same number of nozzles as those of the ink jet printer of the above-described first embodiment are used, and the yellow, magenta, cyan, and black heads are in a straight line with no gaps between the heads. FIG. 6 is a schematic diagram showing an operation in a color recording mode and a monochrome recording mode in the case of being arranged in a line.

In FIG. 24, first, the first scan of the carriage 1 is used to print with the first to 24th nozzles of the black head, and the second scan is used to print with all the nozzles of the cyan head 32. Next, in the third scanning of the carriage 1, recording is performed by all the nozzles of the magenta head 31, and by the fourth scanning of the carriage, recording is performed by all the nozzles of the yellow head 30. Is discharged.

By thus reciprocally moving the carriage 1 four times in the main scanning direction, a color image of 24 rasters can be recorded on the recording paper.

Further, FIG. 25 shows that when a color image is recorded when there is no gap between the heads as described above, an image of 48 rasters is recorded using the 1st to 48th nozzles of the black head 33. It is a schematic diagram which shows the operation | movement.

By the reciprocating movement of the carriage 1 in the main scanning direction for the first time, black data for 48 nozzles is recorded by using the 1st to 48th nozzles of the black head 33, and the cyan data is recorded by the second carriage scanning. Cyan data is recorded by all the nozzles of the head 32. Then, by the third carriage scan, magenta data is recorded by all the nozzles of the magenta head 31, and at the same time, cyan data is recorded by all the nozzles of the cyan head 32. Next, in the fourth scanning, yellow data is printed by all the nozzles of the yellow head 30, and at the same time, magenta data is printed by using all the nozzles of the magenta head 31. And 5
In the second scan, yellow data is recorded by all the nozzles of the yellow head 30.

In the first, third and fifth scans, black data is recorded in 48 raster units by the first to 48th nozzles of the black head 33. By thus reciprocating the carriage 5 times in the main scanning direction, a color image of 48 rasters can be recorded on the recording paper.

In this case as well, it is a matter of course that the preliminary ejection control is performed for each print head as in the above-described embodiment.

In this way, by making the nozzles used in the black head 33 constant, it is possible to prevent uneven density of the black ink on the recording paper.

FIG. 26 and FIG. 27 are schematic diagrams showing the control of changing the nozzles used in the black head 33a during color recording and recording in the ink jet printer having the recording head 2a of the second embodiment described above.

In the first scan of the carriage 1, printing is performed using all the nozzles of the cyan head 32, and at the same time, black data is printed by the 65th to 88th nozzles of the black head 33a. Then, by the second scanning of the carriage 1, magenta data is recorded by the ninth to 24th nozzles of the magenta head 31. Next, in the third reciprocating movement of the carriage 1 in the main scanning direction, black data is recorded by the 41st nozzle to the 64th nozzle of the black head 33a.
Next, by scanning the carriage 1 for the fourth time, magenta data is recorded by the first to eighth nozzles of the magenta head 31. At the same time yellow head 3
Yellow data is recorded from the 17th nozzle to the 24th nozzle of 0.

Next, the recording paper is conveyed by 48 nozzles by driving the paper feed motor 25, and black data is recorded by the 17th nozzle to the 40th nozzle of the black head 33a by the fifth scanning of the carriage 1. And 6
Before the first scanning of the carriage 1, the paper feed motor 25 is reversely rotated to return the recording paper by 24 nozzles, and the yellow data is recorded by the 1st to 16th nozzles of the yellow head 30. Then, before the seventh scanning, the recording paper is conveyed by 48 nozzles, and the black head 33a
The black data is recorded by the first to 24th nozzles.

In this way, by reciprocating the carriage 7 times in the main scanning direction, it is possible to record a color image of N rasters on the recording paper by using all the black nozzles.

As described above, according to the color recording of this embodiment, 24 of the nozzles of the black head 33a are used.
Recording can be performed using all nozzles while changing the nozzle position of the book. As a result, it is possible to prevent density unevenness of the black image between the nozzles that are frequently used and the nozzles that are frequently used.

Further, by performing the preliminary ejection control shown in the above-mentioned embodiment, the use frequency of all the nozzles of the black head 33a is made uniform.

Further, FIG. 28 is a schematic diagram showing an example in which, when recording a monochrome image, among the 88 nozzles of the black head 33a, 44 nozzles are alternately used for each scanning of the carriage 1. Is. Here carriage 1
The recording paper is conveyed by 44 nozzles for each scan of.

FIG. 29 is a schematic diagram showing a recording operation by a recording head having the same head arrangement as that of the recording head 2a of the second embodiment and having no gap between the recording heads. Here, the number of nozzles of the black head 33b is 7.
It is 2.

FIG. 29 shows that when a color image is recorded,
Recording is performed using the 49th nozzle to the 72nd nozzle of the black head 33b.

In the first reciprocating movement of the carriage 1 in the main scanning direction, recording is performed using all the nozzles of the cyan head 30 and the 49th to 72nd nozzles of the black head 33b. Next, in the second carriage scan, black data is recorded by the 49th nozzle to the 72nd nozzle of the black head, and magenta data is recorded by all the nozzles of the magenta head 31. Then, in the third reciprocating movement of the carriage 1 in the main scanning direction, recording is performed using the 49th nozzle to the 72nd nozzle of the black head 33b, and the yellow data is recorded using all the nozzles of the yellow head 30.

Thus, by reciprocating the carriage 1 equipped with such a recording head three times in the main scanning direction, a color image of 24 rasters can be recorded on the recording paper.

In the operation as shown in FIG. 30, the recording operation when using 48 nozzles of the black head 33b at the time of color recording will be described below. Here, when the carriage 1 moves in the main scanning direction, all nozzles of the yellow, magenta, and cyan heads and the black head 33b.
The recording is performed using the 25th nozzle to the 72nd nozzle. Further, the recording sheet is conveyed by 24 nozzles in the sub-scanning direction for each scan.

Here, in the first reciprocating movement of the carriage 1 in the main scanning direction, cyan data is recorded by using all the nozzles of the cyan head, and by the second scanning of the carriage 1, recording is performed by all the nozzles of the magenta head 31. And the 7th from the 25th nozzle of the black head 33b.
Black data is recorded by the second nozzle. Then, in the third reciprocating movement of the carriage 1 in the main scanning direction, recording is performed by all the nozzles of the yellow head 30.

As described above, in the case of color recording of this embodiment,
The number of used nozzles of the black head 33b can be changed to 24 nozzles or 48 nozzles. On the other hand, when recording a monochrome image, recording is performed using all nozzles of the black head 33b. For this reason, the frequency of use of the nozzles used greatly differs between the color recording and the monochrome image recording. For example, the black head 33
Since the frequency of use is different between the 1st nozzle to the 24th nozzle and the 25th nozzle to the 72nd nozzle of b, when the recording of the color image is switched to the recording of the monochrome image, the image unevenness occurs. Occurs.

Therefore, by performing the preliminary ejection control as described in the above embodiment, the usage frequency of all the nozzles of the black head is made uniform.

The present invention may be applied to a system composed of a plurality of devices or an apparatus composed of a single device. Further, it goes without saying that the present invention can also be applied to the case where it is achieved by supplying a program for implementing the present invention to a system or an apparatus.

As described above, according to the present embodiment, the density of the recorded image is changed when the color image recording is changed to the monochrome image recording or when the monochrome image recording is changed to the color image recording. An image can be recorded on the recording medium without unevenness.

In addition, it is possible to suppress the consumption of ink as much as possible and further improve the recording quality.

[0105]

As described above, according to the present invention, there is an effect that it is possible to record a high-quality image while suppressing the density unevenness of the recorded image.

[Brief description of drawings]

FIG. 1 is a perspective view showing a main part of a recording unit of an inkjet printer according to an embodiment of the present invention.

FIG. 2 is a perspective view of the back side of the recording head unit of the first embodiment of the invention.

FIG. 3 is a front perspective view of the recording head unit according to the first embodiment of the present invention.

FIG. 4 is an enlarged front view of the recording head unit according to the first embodiment of the invention.

FIG. 5 is a block diagram showing a schematic configuration of an inkjet printer according to an embodiment of the present invention.

FIG. 6 is a schematic diagram showing an operation at the time of recording a color image in units of 24 nozzles in the first embodiment.

FIG. 7 is a schematic diagram showing an operation at the time of recording a color image in units of 48 nozzles in the first embodiment.

FIG. 8 is a schematic diagram showing an operation when recording a monochrome image in units of 64 nozzles in the first embodiment.

FIG. 9 is a flowchart showing a recording process of the first embodiment of the present invention.

FIG. 10 is a flowchart showing a recording process according to the first embodiment of the present invention.

FIG. 11 is a flowchart showing a preliminary ejection process of the present embodiment.

FIG. 12 is a flowchart showing a modified example of the preliminary ejection process of FIG.

FIG. 13 is a schematic diagram showing a process of recording a color image by changing the position of nozzles used in the black head according to the second embodiment of the present invention.

FIG. 14 is a schematic diagram illustrating a process of recording a monochrome image by changing the position of nozzles used by the black head.

FIG. 15 is a schematic diagram showing a color image recording operation when yellow data is not included.

FIG. 16 is a diagram for explaining the data content of a buffer for each color when recording a color image.

FIG. 17 is a diagram for explaining the data content of each color buffer when recording a monochrome image.

FIG. 18 is a perspective view of the back side of the recording head unit of the third embodiment of the invention.

FIG. 19 is a front perspective view of a recording head unit according to a third embodiment of the invention.

FIG. 20 is an enlarged front view of the recording head unit according to the third embodiment of the present invention.

FIG. 21 is a schematic diagram showing a recording process using 24 nozzles of a black head at the time of recording a color image according to the third embodiment.

FIG. 22 is a schematic diagram showing the basic operation of the third embodiment when 48 nozzles of a black head are used during color image recording.

FIG. 23 is a schematic diagram showing processing in the case of recording a monochrome image using all the nozzles of the black head with the recording head of the third embodiment.

FIG. 24 is a schematic diagram showing a color image recording process using 24 nozzles of the black head when there is no gap between the heads in the recording head of the first embodiment.

FIG. 25 is a schematic diagram showing a color image recording process using 48 nozzles of a black head when there is no gap between the heads in the recording head of the first embodiment.

FIG. 26 is a schematic diagram showing an operation of recording a color image by changing the used nozzle position of the black head in units of 24 nozzles in the recording head of the second embodiment.

FIG. 27 is a schematic view showing an operation of recording a color image by changing the used nozzle position of the black head in units of 24 nozzles in the recording head of the second embodiment.

FIG. 28 is a schematic diagram showing an operation of recording a monochrome image by changing the used nozzle position of the black head with the recording head of the second embodiment.

FIG. 29 is a schematic diagram showing an operation of recording a color image in units of 24 nozzles when there is no gap between the color recording heads in a modification of the recording heads of the second embodiment.

FIG. 30 is a schematic diagram showing an operation of changing the used nozzle position of the black head and recording when there is no gap between the color recording heads in a modification of the recording heads of the second embodiment.

[Explanation of symbols]

 1 Carriage 2, 2a, 2b Recording Head 3 Cartridge Guide 10 Color Ink Cartridge 11 Black Ink Cartridge 20 Control Unit 21 Head Driver 24 Carriage Motor 25 Paper Feed Motor 30 Yellow Head 31 Magenta Head 32 Cyan Head 33 Black (Black) Head 210 CPU 211 ROM 213 RAM 214 Yellow buffer 215 Magenta buffer 216 Cyan buffer 217 Black buffer

Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI Technical display location B41J 3/54 B41M 5/00 A 8808-2H 8703-2C B41J 3/12 G

Claims (5)

[Claims] 1. An ink jet recording apparatus for recording by ejecting ink to a recording medium, wherein a plurality of recording heads each having a plurality of nozzles are provided, and the plurality of recording heads have different numbers of nozzles. ,
An ink jet recording apparatus comprising: a recording unit that records by using a predetermined nozzle of another recording head corresponding to the number of nozzles of the recording head having the smallest nozzle. 2. The ink jet recording apparatus according to claim 1, wherein the recording means further records by using nozzles of the other recording head substantially evenly. 3. An ink jet recording apparatus for ejecting ink to a recording medium for recording, comprising a plurality of color recording heads for recording images of respectively different colors, and more than each of the plurality of recording heads. A black recording head having nozzles for recording black data, and at the time of recording a color image, recording using a predetermined number of predetermined nozzles corresponding to the number of nozzles of the color recording head in the black recording head An ink jet recording apparatus comprising: a recording unit that records all the nozzles of the black recording head as targets for use when recording a monochrome image. 4. The ink jet recording apparatus according to claim 3, further comprising an ejection unit that performs a preliminary ejection operation to nozzles of a recording head that is not used during recording by the recording unit. 5. An inkjet recording method for recording a color image by ejecting ink from a plurality of recording heads onto a recording medium, wherein when the plurality of recording heads have different numbers of nozzles, the recording head having the smallest number of nozzles is used. A step of recording a color image by using a predetermined nozzle of another recording head corresponding to the number of nozzles, and a step of recording all the nozzles of the recording head for black when using a monochrome image, And a step of performing preliminary ejection to nozzles that are not the target of use when recording a color image or recording a monochrome image.