JPH10778A - Ink jet recording method and apparatus therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the deterioration of recording image quality while performing high speed recording by variably setting the line feed pitch of paper in the sub-scanning direction crossing a main scanning direction at a right angle and the scanning speed of a head when recording is applied to a recording medium by ink particles flying from nozzles in a high image quality recording mode. SOLUTION: When a recording mode is a high image quality recording mode, it is judged wether the recording mode is a detailed recording mode or an ultra-detailed recording mode (S15) and, in the case of the detailed recording mode, the line feed pitch P1 [P1<P (wherein p is the line feed pitch of paper in a standard recording mode)] of paper is set (S16) and the head scanning speed hp2 (hp2>hp1) corresponding to the line feed pitch P1 is set (S17). Image data to be recorded is developed on an RAM (S18). In the case of the ultra-detailed recording mode, the line feed pitch P2 (P2<P1) of paper is set (S19) and the head scanning speed hp3 (hp3>hp2) corresponding to the line feed pitch P2 is set (S20). The image data to be recorded is developed on the RAM. For example, the line feed pitch P2 is four dots and the head is scanned four times with respect to one dot line and the scanning speed hp3 of the head is about four times hp1.

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, and more particularly, to an ink jet recording method and apparatus for suppressing deterioration in recording image quality due to variations in the flying direction of ink particles.

[0002]

2. Description of the Related Art In an ink jet recording apparatus, one line is recorded by scanning a head in a main scanning direction while a sheet of paper is stationary. Thus, one line is recorded with dots (dot lines) for the number of nozzles of the head.
Then, after the paper is fed in the sub-scanning direction, the next line is recorded in the same manner. By repeating such operations,
Image information such as characters, symbols, and figures is recorded on one page of paper.

[0003]

By the way, the flying direction of the ink particles flying from each nozzle of the head has a small defect in the nozzle part due to the ink adhering to the nozzle part or a variation in manufacturing of the nozzle. Therefore, even if driven by the same drive signal, they are not all the same. Actually, the flying direction of the ink particles has a three-dimensional variation depending on the nozzle. In addition, nozzle driving means such as a piezo element that causes ink to fly to each nozzle cannot drive all the nozzles in the same state with respect to the same drive signal due to manufacturing variations and the like. The flying direction of the flying ink particles is different. When ink has adhered to the nozzle portion, it is possible to correct variations in the flying direction of the ink particles by cleaning the nozzle portion and removing the attached ink. However, the variation in the flight direction of the ink particles due to the manufacturing variation of the nozzles and the nozzle driving means is unique to each ink jet recording apparatus, and it is very difficult to correct the flight direction of the ink particles.

If the flying direction of ink particles varies in the main scanning direction of the head, white or black streaks appear in the sub-scanning direction on paper in the case of monochrome recording. in this case,
A white streak indicates an unrecorded portion (recorded skip portion) that occurs on paper that is normally white due to separation of adjacent dot lines. A black streak indicates a darkly recorded portion that occurs on paper due to overlapping of adjacent dot lines. On the other hand, if the flying direction of the ink particles varies in the sub-scanning direction, white or black streaks appear on the paper in the main scanning direction in monochrome recording. Similarly, in the case of color recording, white streaks or streaks of various colors appear in the main scanning direction or the sub-scanning direction on paper depending on the direction of variation of the flying direction of ink particles.

[0005] If white streaks, black streaks, or streaks of various colors occur on paper as described above, there has been a problem that the recorded image quality is degraded. Such deterioration of the recording image quality
Especially when the number of dots for recording one line is small, that is,
This was particularly noticeable when the recording resolution was low.

In order to prevent the deterioration of the recording image quality, the allowable range of the flying direction of the ink particles from each nozzle may be narrowed. However, when the allowable range of the flying direction of the ink particles is narrowed, the yield of the head is reduced, and the head becomes very expensive, and the entire inkjet recording apparatus becomes expensive.

Therefore, the present invention provides an ink-jet recording method capable of suppressing deterioration of recording image quality and performing high-speed recording even when using an inexpensive head in which the flying direction of ink particles from nozzles varies. And an apparatus.

[0008]

The above object is attained by claim 1.
In the ink jet recording method for recording image information on a recording medium by scanning a head having a plurality of nozzles that fly ink particles in a main scanning direction according to the above, one dot line is formed on the recording medium by ink particles flying from the same nozzle. In the high-quality recording mode, in which recording is performed with higher image quality, unlike the standard recording mode in which recording is performed on the recording medium, the head is scanned n times, and one dot line is recorded on the recording medium by ink particles flying from n nozzles. A step of variably setting a line feed pitch p of the paper in a sub-scanning direction orthogonal to the main scanning direction in accordance with the value of n in the high-quality recording mode; Variably setting the scanning speed of the head in accordance with the value of (i).

According to a second aspect of the present invention, the method according to the first aspect further includes a step of setting the value of n. In the invention according to claim 3, in the invention according to claim 1 or 2,
Assuming that the line feed pitch of the paper in the standard recording mode is P, the line feed pitch p in the high image quality recording mode is P.
Is set to satisfy p = P / n.

According to a fourth aspect of the present invention, in the invention of any one of the first to third aspects, the step of variably setting the scanning speed of the head in the high image quality recording mode comprises the step of:
The scanning speed of the head is set to about n times the scanning speed in the standard recording mode in accordance with the value of.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the value of n is 2 or 4. According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the flying amount of the ink particles from each nozzle is kept constant, and the flying speed of the ink is set to a different value according to the nozzle. The method further includes a step.

According to the present invention, there is provided an ink jet recording method for recording image information on a recording medium by scanning a head having a plurality of nozzles for ejecting ink particles. Ink jet recording including a step of keeping the amount constant and setting the flying speed of the ink to a different value according to the nozzle, and a step of recording each dot line on a recording medium by ink particles flying from the corresponding nozzle It is also achieved by the method.

In the invention according to claim 8, in the invention according to claim 7, the step of setting the flying speed of the ink to a different value according to the nozzle comprises changing a signal waveform for driving the nozzle according to the nozzle to a different waveform. Set. According to the present invention, there is provided a head having a plurality of nozzles that fly ink droplets when driven, and scanning the head in the main scanning direction, so that image information is obtained by ink droplets flying from driven nozzles. Means for recording on a recording medium, means for feeding the paper in a sub-scanning direction orthogonal to the main scanning direction, and standard recording mode for recording one dot line on a recording medium by ink particles flying from the same nozzle On the other hand, in the high-quality recording mode for recording with higher image quality, the head is set to n
Means for controlling the scanning means so as to perform multiple scans and selectively driving the nozzles so that one dot line is recorded on a recording medium by ink particles flying from n nozzles; means for variably setting the line feed pitch p of the paper in the sub-scanning direction in accordance with the value of n; and means for variably setting the scanning speed of the head in accordance with the value of n in the high image quality recording mode. This is also achieved by an ink jet recording apparatus.

According to the present invention, there is provided a head having a plurality of nozzles which fly ink particles when driven, and scanning the head to record image information by the ink particles flying from the driven nozzles. Means for recording on a medium, setting means for keeping the flying amount of ink particles from each nozzle constant, and setting the flying speed of ink to a different value according to the nozzle, and flying each dot line from the corresponding nozzle. The present invention is also achieved by an ink jet recording apparatus provided with means for driving the nozzle so that recording is performed on a recording medium by ink particles.

According to the first and ninth aspects of the present invention, even if an inexpensive head in which the flying direction of the ink particles from the nozzle fluctuates is used, the deterioration of the recording image quality is suppressed and the recording is performed at high speed. be able to. According to the second aspect of the present invention, the value of n can be arbitrarily set according to a desired recording image quality.

According to the third aspect of the invention, high recording image quality can be realized. According to the invention described in claim 4, high-speed recording can be realized. According to the fifth aspect of the present invention, the selective driving of each nozzle can be controlled by simple means.

According to the sixth aspect of the present invention, the recorded image quality can be further improved. According to the seventh and tenth aspects of the present invention, even if an inexpensive head in which the flying direction of the ink particles from the nozzle fluctuates is used, it is possible to suppress the deterioration of the recording image quality and perform high-speed recording. .

According to the present invention, the flying speed of the ink particles can be controlled by a simple means. Therefore, according to the present invention, high recording image quality and high recording speed can be realized by a relatively inexpensive inkjet recording apparatus.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a first embodiment of the present invention,
When a head having a plurality of nozzles that fly ink particles is scanned in the main scanning direction to record image information on a recording medium, one dot line is recorded on the recording medium by ink particles flying from the same nozzle. Unlike the mode, in the high-quality recording mode in which recording is performed with higher image quality, the head is scanned n times and one dot line is recorded on the recording medium by ink particles flying from n nozzles.
In the high-quality recording mode, the line feed pitch p of the paper in the sub-scanning direction orthogonal to the main scanning direction is variably set in accordance with the value of n, and the scanning speed of the head is varied in accordance with the value of n. Set. As a result, even if an inexpensive head having variations in the direction in which ink particles fly from the nozzles is used, it is possible to suppress deterioration in recording image quality and perform high-speed recording.

In the second embodiment of the present invention, when the image information is recorded on a recording medium by scanning a head having a plurality of nozzles for flying ink particles, the flying amount of the ink particles from each nozzle is The flying speed of the ink is set to a different value depending on the nozzle, while keeping it constant. Each dot line is recorded on a recording medium by ink particles flying from a corresponding nozzle. As a result, even if an inexpensive head having variations in the direction in which ink particles fly from the nozzles is used, it is possible to suppress deterioration in recording image quality and perform high-speed recording.

Further, as a third embodiment of the present invention,
The first and second embodiments may be combined.
In this case, the recording image quality can be further improved.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a first embodiment of the ink jet recording apparatus according to the present invention will be described. In the first embodiment of the ink jet recording apparatus, the first embodiment of the ink jet recording method according to the present invention is employed.

FIG. 1 is a block diagram showing a schematic configuration of an ink jet recording apparatus according to this embodiment together with a host apparatus. In FIG. 1, an ink jet recording apparatus (hereinafter, simply referred to as a printer) 1 is connected to a host device 3 via an interface 2. The host device 3 is, for example, a personal computer having a printer driver 32 activated by application software 31.

The printer 1 generally includes a central control unit (CP)
U) 11, a read only memory (ROM) 12, an external interface (IF) 13 for controlling an interface with the host device 3, and a random access memory (RA).
M) 14, a mechanical interface (IF) 15 for controlling an interface with a mechanical part 21 of the printer 1, a head drive interface (IF) 16 for controlling an interface with a head 25 described later, a bus 17, a paper feed motor driver 18, a head. It comprises a feed motor driver 19, a head driver 20, and a mechanical part 21. Bus 17 is R
The OM 12, the external IF 13, the RAM 14, the mechanical IF 15, and the head drive IF 16 are connected to the CPU 11.

The mechanical part 21 includes a sensor group 22 connected to the mechanical IF 18, a paper feed motor 23 driven by the paper feed motor driver 18, a head feed motor 24 driven by the head feed motor driver 19, and a head. And a head 25 driven by the driver 20. The head 25 includes a nozzle selection circuit 26 and a piezo element 27.

The CPU 11 controls the operation of the printer 1 as a whole. The ROM 12 stores programs executed by the CPU 11, data, and the like in advance. RAM 14 is a CP
U11 stores data and intermediate data used when executing the program. The external IF 13 notifies the CPU 11 of image information and control information obtained via the printer driver 32 of the host device 3, and
Is notified to the host device 3. Incidentally, the image information is usually stored in the RAM 14 once.

The mechanical IF 15 controls the driving of a paper feed motor 23 via a paper feed motor driver 18 based on an instruction from the CPU 11, and a head feed motor driver 19.
Drive control of the head feed motor 24 via
The detection signal from the sensor group 22 is notified to the CPU 11.
The paper feed motor 23 drives a well-known paper feed mechanism (not shown) to feed paper (not shown) used as a recording medium in the sub-scanning direction at a specified line feed pitch (paper feed pitch). On the other hand, the head feed motor driver 19 drives a well-known head feed mechanism (not shown) to feed the head 25 in the main scanning direction at the designated scanning speed. The main scanning direction is a direction orthogonal to the sub-scanning direction. The sensor group 22 includes a sensor for detecting a paper jam, a sensor for detecting the size of paper attached to the printer 1, and the like, and notifies the CPU 11 of a detection signal indicating a detection result via the mechanical IF 15.

The head drive IF 16 controls the drive of the head 25 via the head driver 20 based on an instruction from the CPU. The head driver 20 selects a nozzle (not shown) of the head 25 to be driven via the nozzle selection circuit 26. The piezo element 27 corresponding to the selected nozzle is driven by the nozzle selection circuit 26.

The components of the printer 1 shown in FIG. 1 may be of a known structure, and therefore, detailed description thereof will be omitted in this specification. That is, the present embodiment is characterized in particular by the operation of the CPU 11 that controls the entire operation of the printer 1, and the configuration of the printer 1 is not limited to the configuration shown in FIG. It is applicable to printers of various configurations.

FIG. 2 is a diagram schematically showing the nozzle arrangement of the head 25 when the printer 1 performs color printing.
In the figure, each circle indicates one nozzle, K1 to K15 are nozzles that fly black ink, C1 to C15 are nozzles that fly cyan ink, M1 to M15 are nozzles that fly magenta ink, Y1 to Y15 Denotes a nozzle that flies the yellow ink. The horizontal direction corresponds to the main scanning direction of the head 25, and the vertical direction corresponds to the sub-scanning direction in which the paper is fed. In this case, the nozzles are arranged in the sub-scanning direction at the same number of dots as the number of nozzles (the number of dots) per color. The nozzles of each color are arranged in the sub-scanning direction at a pitch corresponding to a predetermined resolution. That is, in FIG. 2, the number of nozzles for each color of the head 25 is 16, and the nozzle groups of each color are arranged in the sub-scanning direction at intervals of 16 dots. The colors of the color inks other than black are not limited to yellow, magenta, and cyan.

FIGS. 3 to 5 are views for explaining the recording operation in the present embodiment. FIG. 3 is a diagram for explaining the operation in the standard recording mode, and FIGS. 4 and 5 are diagrams for explaining the operation in the high-quality recording mode. For convenience of explanation,
FIGS. 3 to 5 show only recording of 16 dots corresponding to the number of nozzles per color (= 16), and recording using black ink will be described as an example. Recording with other color inks is performed in the same manner, and a description thereof will be omitted. Further, it is assumed that the flight direction of the ink from the lowermost nozzle varies below the design value, and the flight direction of the ink from the second lowermost nozzle varies above the design value.

The line feed pitch P in the standard recording mode is
It is assumed to be 16 dots. In this case, since one dot line is recorded by the same nozzle of the head 25, when the head 25 is scanned once in the main scanning direction, the bottom and the second from the bottom indicated by black circles in FIG. The nozzle is driven to record a dot at a corresponding position. As described above, in this case, the flying directions of the ink from the bottom nozzle and the second nozzle from the bottom vary in the direction away from each other, so that the dots recorded on the paper are indicated by black circles in FIG. become,
White streaks occur in the main scanning direction. Although illustration is omitted, on the contrary, if the flying directions of the ink from the bottom nozzle and the second nozzle from the bottom vary in a direction approaching each other, the dots recorded on the paper partially overlap. However, the darkly recorded portions become black streaks, which occur in the main scanning direction.

In the high image quality recording mode, the line feed pitch p is set smaller than the line feed pitch P in the standard recording mode so that the white streaks and black streaks are not conspicuous, so that it is possible to perform recording with higher image quality than the standard recording mode. I do. In this embodiment, the high-quality recording mode includes two modes, a fine recording mode and an ultra-fine recording mode. In the fine recording mode, the line feed pitch p is set to 8 dots, and in the ultra-fine recording mode, the line feed pitch p is set to 4 dots.

In the fine recording mode, when the head 25 is scanned once in the main scanning direction, the lowest nozzle and the second nozzle from the bottom indicated by a black circle in FIG. That is, half the amount of image information recorded in the standard recording mode is recorded. As described above, in this case, the flying directions of the ink from the bottom nozzle and the second nozzle from the bottom vary in the direction away from each other, and thus white streaks are generated on the recorded paper in the main scanning direction. Next, the paper is fed in the sub-scanning direction by a line feed pitch p1 of 8 dots, and the head 25 is again scanned in the main scanning direction.
In this case, the ninth and tenth nozzles from the bottom, which are located 8 dots (line feed pitch p1) in the sub-scanning direction from the bottom and the second nozzle from the bottom indicated by black circles in FIG. When driven, the dot at the corresponding position, that is, the remaining image information is recorded. The flying directions of the inks from the ninth and tenth nozzles from the bottom are assumed to be substantially the same as the design values for convenience of description, but at least the flying directions of the inks from the bottom nozzle and the second nozzle from the bottom. Since it is very unlikely that they are exactly the same, they need not always be as designed. Therefore, the dots recorded on the paper by the two scans are indicated by black circles in FIG.
It can be seen that the image quality is improved as compared with the case (b).

In the ultra-fine recording mode, when the head 25 is scanned once in the main scanning direction, the lowermost nozzle and the second nozzle from the bottom indicated by black circles in FIG. Dots, that is, image information of １ ／ of the image information recorded in the standard recording mode is recorded. As described above, in this case, the flying directions of the ink from the bottom nozzle and the second nozzle from the bottom vary in the direction away from each other, and thus white streaks are generated on the recorded paper in the main scanning direction. Next, the paper is fed in the sub-scanning direction by a line feed pitch p2 of 4 dots, and the head 25 is again scanned in the main scanning direction. In this case, the 5th and 6th nozzles from the bottom located 4 dots (line feed pitch p2) in the sub-scanning direction from the 2nd nozzle from the bottom and 2nd from the bottom indicated by a black circle in FIG. When driven, a dot at a corresponding position, that is, image information of 1/3 of the remaining image information is recorded. The flying directions of the inks from the fifth and sixth nozzles from the bottom are assumed to be substantially the same as the design values for convenience of explanation, but at least the flying directions of the inks from the bottom and the second nozzle from the bottom. Since it is very unlikely that they are exactly the same, they need not always be as designed. Next, the paper is further fed in the sub-scanning direction by a line feed pitch p2 of 4 dots, and the head 25 is again scanned in the main scanning direction. In this case, the ninth and tenth nozzles from the bottom located four dots (line feed pitch p2) above in the sub-scanning direction from the fifth and sixth nozzles from the bottom indicated by black circles in FIG. And the dot at the corresponding position, ie, の of the remaining image information
Of image information is recorded. The flying directions of the inks from the ninth and tenth nozzles from the bottom are assumed to be substantially the same as the design values for convenience of explanation, but at least the nozzles at the bottom and the second from the bottom or the fifth and sixth from the bottom. Since it is very unlikely that the ink jetting direction from the third nozzle is exactly the same, it does not necessarily have to be as designed.
Then, the paper is further fed in the sub-scanning direction by a line feed pitch p2 of 4 dots, and the head 25 is again scanned in the main scanning direction. In this case, the thirteenth and fourteenth nozzles from the bottom located four dots (line feed pitch p2) in the sub-scanning direction from the ninth and tenth nozzles from the bottom indicated by black circles in FIG. The corresponding position dot,
That is, the remaining image information is recorded. The flying directions of the ink from the thirteenth and fourteenth nozzles from the bottom are assumed to be substantially the same as the design values for convenience of description, but at least the bottom and second nozzles, and the fifth and sixth nozzles from the bottom. It is very unlikely that the ink jetting direction from the ninth nozzle or the ninth and tenth nozzles from the bottom is exactly the same, so it is not necessarily required to be as designed. Accordingly, the dots recorded on the paper by the four scans are indicated by black circles in FIG. 5E, and it can be seen that the image quality is improved as compared with the case of FIG. 3B.

By the way, in the high-quality recording mode, the image quality can be greatly improved as compared with the standard recording mode even if the head 25 composed of nozzles having a slight variation in the ink flying direction is used. The number of scans increases according to the line feed pitch p. Therefore, in the high-quality recording mode, when the head 25 is scanned n times to record one dot line on the paper by the ink particles flying from the n nozzles, it is orthogonal to the main scanning direction according to the value of n. In addition to variably setting the line feed pitch p of the paper in the sub-scanning direction,
The scanning speed of the head 25 is variably set according to the value of n.
Specifically, assuming that the line feed pitch of the paper in the standard recording mode is P, the line feed pitch p in the high-quality recording mode is set so as to satisfy p = P / n.
Is set to about n times that in the standard recording mode. As a result, even if the number of scans for one dot line by the head 25 is increased as compared with the standard recording mode, high-quality recording can be realized while maintaining the recording speed at substantially the same level as in the standard recording mode.

The image information dividing process for dividing and recording the image information in the high image quality recording mode can use a well-known method, and thus the description thereof is omitted. In the case where one dot line is printed by scanning the head 25 a plurality of times, it goes without saying that printing may be performed only on the outward path in the main scanning direction of the head 25, or on both the outward path and the return path. . If you want to record on both the outbound and return trips,
It is necessary to reverse the order of the image information for each line,
Since a well-known method can be used for the inversion process itself, the description thereof is omitted.

Further, the high-quality recording mode is not limited to the two modes of the fine recording mode and the super-fine recording mode, and three or more types of high-quality recording modes may be provided. Next, the operation of this embodiment will be described with reference to the flowchart shown in FIG. FIG. 6 corresponds to the operation of the CPU 11 shown in FIG.

In FIG. 6, when the printer driver 32 of the host device 3 is activated and the control information including the recording mode and the image information to be recorded are supplied from the printer driver 32 to the external IF 13 of the printer 1, the CPU 11 proceeds to step S11. To determine whether the recording mode is the standard recording mode or the high quality recording mode. When the recording mode is the standard recording mode, the line feed pitch P of the paper is set in step S12, and the head scanning speed hp1 according to the line feed pitch P is set in step S13. Step S14
Expands the image information to be recorded on the RAM 14.
In this case, the image information is developed on the RAM 14 in accordance with the recording order such that one dot line is recorded by the same nozzle of the head 25 by one scan of the head 25.
The line feed pitch P is, for example, 16 dots.

On the other hand, if the recording mode is the high-quality recording mode, it is determined in step 15 whether the recording mode is the fine recording mode or the ultra-fine recording mode. In the fine recording mode, in step S16, the line feed pitch p1 (p1
<P) is set, and in step S17, the head scanning speed hp2 (hp2> hp1) according to the line feed pitch p1 is set. In step S18, the image information to be recorded is
Deploy on AM14. In this case, as for the image information, one dot line is formed by a plurality of scans of the head 25.
In accordance with the printing order and the number of scans of the head 25 for one dot line, so that printing is performed by a plurality of nozzles.
Expanded on M14. The line feed pitch p1 is, for example, 8 dots, the head 25 is scanned twice for one dot line, and the head scanning speed hp2 is about twice as high as hp1.

In the case of the ultra-fine recording mode, step S19
Sets the line feed pitch p2 (p2 <p1) of the paper. In step S20, the head scanning speed h according to the line feed pitch p2 is set.
p3 (hp3> hp2) is set. Step S21
Expands the image information to be recorded on the RAM 14.
In this case, the image information is stored on the RAM 14 in accordance with the recording order and the number of scans of the head 25 for one dot line so that one dot line is recorded by a plurality of nozzles of the head 25 by multiple scans of the head 25. Be expanded.
The line feed pitch p2 is, for example, 4 dots.
Is scanned four times for one dot line, and the head scanning speed hp3 is about four times as high as hp1.

In the case of the standard recording mode, a step S22 sequentially reads out image information from the RAM 14, and according to the image information, the head driver 20 via the head drive IF 16.
By controlling the head feed motor driver 19 via the mechanical IF 15, the image information is recorded on the paper by one scan of the head 25. Step S2
When the recording of one line is completed, the paper is fed by the line feed pitch P in the sub-scanning direction by controlling the paper feed motor driver 18 via the mechanical IF 15 when the recording of one line is completed. Step S24
Determines whether there is a next line to be recorded, and if the determination result is YES, the process proceeds to step S1.
Return to 4.

In the fine recording mode, in step S22, image information is sequentially read from the RAM 14 and the head driver 20 is read via the head drive IF 16 in accordance with the image information.
, And by controlling the head feed motor driver 19 and the paper feed motor driver 18 via the mechanical IF 15, the image information is printed on the paper by one paper feed of one line feed pitch p1 and two scans of the head 25. To record. In step S23, when the recording of one line is completed, the mechanical I
By controlling the paper feed motor driver 18 via F15, the paper is fed by the line feed pitch p1 in the sub-scanning direction. A step S24 decides whether or not there is a next line to be recorded. If the decision result in the step S24 is YES, the process returns to the step S14.

In the case of the ultra-fine recording mode, step S22
Sequentially reads out image information from the RAM 14 and, according to the image information, reads the head driver 2 via the head drive IF 16.
0, and by controlling the head feed motor driver 19 and the paper feed motor driver 18 via the mechanical IF 15, image information can be obtained by three paper feeds for a line feed pitch p2 and four scans of the head 25. Record on paper.
In step S23, when the recording of one line is completed, the paper is fed by the line feed pitch p2 in the sub-scanning direction by controlling the paper feed motor driver 18 via the mechanical IF 15. A step S24 decides whether or not there is a next line to be recorded. If the decision result in the step S24 is YES, the process returns to the step S14.

If the decision result in the step S24 is NO, the process ends. As a well-known printer technology,
Printers having a recording mode called a so-called draft mode currently exist. The draft mode is provided for the purpose of shortening the recording time. The draft speed is set to, for example, twice that in the standard recording mode, and the amount of image information to be recorded is reduced to, for example, half or less, and is recorded on paper. For this reason, the resolution of the image information to be recorded is less than half of that in the standard recording mode, and the recording image quality is extremely deteriorated. However, this mode is convenient when it is necessary to quickly know the outline of the recording result.

The high-quality recording mode is completely different in character from the draft mode. In the draft mode, the thinned image information is recorded, so that the recording image quality is significantly lower than in the standard recording mode. On the other hand, in the high image quality recording mode, since image information of one dot line is divided and recorded by a plurality of nozzles, image information to be finally recorded is not thinned out. For this reason, there is no deterioration in the recording image quality due to the division of the image information, and as described above, when the flying direction of the ink from the nozzles varies, the recording image quality is significantly improved rather than in the standard recording mode.

Next, a description will be given of a second embodiment of the ink jet recording apparatus according to the present invention. In the second embodiment of the ink jet recording apparatus, the second embodiment of the ink jet recording method according to the present invention is employed. FIG. 7 is a diagram illustrating the relationship between the flying speed and the flying direction of the ink particles. This figure shows a part of the experimental results of the present inventors with respect to two representative types of inks, and the flight direction indicates a deviation from a design value by an angle. As can be seen from the figure, by the experiments of the present inventors,
Even with the same nozzle, it was confirmed that the higher the flying speed of the ink particles, the smaller the variation in the flying direction with respect to the design value. Therefore, in this embodiment, by controlling the flying speed of the ink particles from the nozzles, the deterioration of the recording image quality due to the variation in the flying direction is suppressed. Specifically, in order to record one dot line with the same nozzle, the nozzle is selectively driven by a drive waveform having a different rate of voltage change contributing to the flight of the ink particles, without changing the flight amount of the ink particles. Recording is performed by changing only the flight speed and consequently changing the flight direction of the ink particles from the same nozzle. Accordingly, high recording image quality can be realized even when a head having a variation in the direction in which the ink particles fly from the nozzles is used. Also, high-speed recording is possible without sacrificing the recording speed for improving the recording image quality.

FIG. 8 is a block diagram showing a configuration of a main part of a second embodiment of the ink jet recording apparatus according to the present invention. For convenience of explanation, it is assumed that the schematic configuration of the second embodiment of the ink jet recording apparatus is the same as that of FIG. In the following description, the circuit shown in FIG. 8 is described as being added to the nozzle selection circuit 26 shown in FIG. 1. However, even if the circuit is connected outside the nozzle selection circuit 26, it is added to the head driver 20. Is connected to the outside of the head driver 20,
Alternatively, it goes without saying that they may be provided separately in the head driver 20 and the nozzle selection circuit 26.

The circuit shown in FIG.
To 43, analog switches 44-1 to 44-n, random number generator 47, registers 48 and 50, and shift register 4
Consists of nine. The drive waveform generation circuits 41 to 43 include a CPU
Trigger signal tR1 is supplied from the random number generator 4
7, a trigger signal tR2 from the CPU 11 is supplied. The latch signal LT from the CPU 11 is supplied to the registers 48 and 50. The shift register 49 has a CP
Clock signal CLK from U11 and head driver 20
Is supplied with the image information DATA to be recorded.

The drive waveform generators 41 to 43 generate three different drive waveforms w1 to w3 in response to the trigger signal tR1, respectively. These drive waveforms w1 to w3
Is generated to cause the ink particles to fly at different flying speeds. The drive waveforms w1 to w3 output from the drive waveform generation circuits 41 to 43 are supplied to all the analog switches 44-1 to 44-n, respectively.

The shift register 49 receives the clock signal CL
In response to K, image information DAT for the number of nozzles of head 25
Take in A. When the shift register 49 takes in the image information DATA for the number of nozzles of the head 25, the image information DATA is temporarily stored in the register 50 in response to the latch signal LT. On the other hand, the 3-bit random number generated from the random number generator 47 in response to the trigger signal tR2 is also temporarily stored in the register 48 in response to the latch signal LT. A 3-bit random number is generated such that only one bit is a logical "1".

The 4-bit outputs of the registers 48 and 50 are supplied as control signals to the analog switches 44-1 to 44-n. Specifically, a 3-bit output of the register 48 is supplied to the select terminal Sel of each of the analog switches 44-1 to 44-n.
The drive waveforms w1 to w3 depend on which one bit of the 3-bit output has the logical value “1”.
One of the corresponding drive waveforms is selectively output. or,
The 1-bit output of the register 50 corresponds to each analog switch 4
4-1 to 44-n are supplied to enable terminals En
When the logical value of the bit output is “1”, each of the analog switches 44-1 to 44-n is activated. That is, if the logical value of the 1-bit output of the register 50 is “0”,
Each of the analog switches 44-1 to 44-n is in a non-operating state, and none of the drive waveforms w1 to w3 is output. On the other hand, if the logical value of the 1-bit output of the register 50 is “1”, each of the analog switches 44-1 to 44-
n is in the operating state, and any one of the drive waveforms w1 to w3 is changed to a corresponding one of the analog switches 44-1 to 44-n.
And output to the corresponding piezo element 27.
Since a different drive waveform is supplied to each piezo element 27 in accordance with the random number generated by the random number generator 47, it is necessary to change the flying speed of the ink particles from the nozzles while keeping the flying amount of the ink particles constant. Can be.

In this embodiment, since the means for driving the nozzle is the piezo element 27, the difference in the driving waveform for changing the flying speed of the ink particles from the nozzle is the voltage per unit time when the ink particles fly. This is reflected in the rate of change, that is, the gradient of the drive waveform. FIG. 9 is a signal waveform diagram for explaining the operation of the second embodiment. FIG. 14 shows the clock signal CLK, image information DATA, latch signal LT, trigger signal tR1, and drive waveforms w1 to w described with reference to FIG.
3 is shown.

In this embodiment, three types of drive waveforms are used. However, the number of types of drive waveforms may be two or four or more. Further, in the present embodiment, the selection of the driving waveform is performed based on the random numbers, but the random numbers need not always be used, and the driving waveforms may be selected regularly. However, in order to effectively suppress the deterioration of the recording image quality due to the variation in the flying direction of the ink particles from the nozzles, it is desirable to select the drive waveform based on a random number.

The first embodiment and the second embodiment can be combined. That is, in the inkjet recording method and apparatus according to the present invention, the first and second embodiments of the inkjet recording method and apparatus are used in combination. Thereby, the recording image quality can be further improved.

The present invention has been described with reference to the embodiments.
The present invention is not limited to the above embodiments, and it goes without saying that various improvements and modifications are possible within the scope of the present invention.

[0057]

According to the first and ninth aspects of the present invention, even if an inexpensive head having a variation in the flying direction of the ink particles from the nozzles is used, the deterioration of the recording image quality is suppressed, and
High-speed recording can be performed.

According to the second aspect of the invention, the value of n can be arbitrarily set according to the desired recording image quality. According to the third aspect of the invention, high recording image quality can be realized.
According to the invention described in claim 4, high-speed recording can be realized.

According to the fifth aspect of the invention, the selective driving of each nozzle can be controlled by simple means. According to the sixth aspect of the invention, the recording image quality can be further improved. According to the seventh and tenth aspects of the present invention, even if an inexpensive head in which the flying direction of the ink particles from the nozzle fluctuates is used, it is possible to suppress the deterioration of the recording image quality and perform high-speed recording. .

According to the present invention, the flying speed of the ink particles can be controlled by simple means. Therefore, according to the present invention, high recording image quality and high recording speed can be realized by a relatively inexpensive inkjet recording apparatus.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of an ink jet recording apparatus according to the present invention together with a host device.

FIG. 2 is a diagram schematically showing an arrangement of nozzles of a head.

FIG. 3 is a diagram for explaining an operation in a standard recording mode.

FIG. 4 is a diagram for explaining an operation in a fine recording mode.

FIG. 5 is a diagram for explaining an operation in an ultra-fine recording mode.

FIG. 6 is a flowchart for explaining the operation of the first embodiment.

FIG. 7 is a diagram illustrating a relationship between a flying speed and a flying direction of ink particles.

FIG. 8 is a block diagram showing a configuration of a main part of a second embodiment of the ink jet recording apparatus according to the present invention.

FIG. 9 is a signal waveform diagram for explaining the operation of the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printer 2 Interface 3 Host device 11 CPU 12 ROM 13 External IF 14 RAM 15 Mechanical IF 16 Head drive IF 17 Bus 18 Paper feed motor driver 19 Head feed motor driver 20 Head driver 21 Mechanical part 22 Sensor group 23 Paper feed motor 24 Head feed motor 25 Head 26 Nozzle selection circuit 27 Piezo element 41 to 43 Drive waveform generation circuit 44-1 to 44-n Analog switch 47 Random number generator 48, 50 register 49 Shift register

Claims (10)

[Claims] 1. An ink jet recording method for recording image information on a recording medium by scanning a head having a plurality of nozzles for flying ink particles in a main scanning direction, wherein one dot line is recorded by ink particles flying from the same nozzle. Unlike the standard recording mode that records on media,
In a high-quality recording mode in which recording is performed with higher image quality, a step of scanning the head n times and recording one dot line on a recording medium with ink particles flying from n nozzles; Variably setting the line feed pitch p of the paper in the sub-scanning direction orthogonal to the main scanning direction according to the value of n; and in the high image quality recording mode, the scanning speed of the head in accordance with the value of n Variably setting the ink jet recording method. 2. The method further comprises the step of setting the value of n.
The inkjet recording method according to claim 1. 3. The line feed pitch p in the high-quality recording mode is set so as to satisfy p = P / n, where P is the line feed pitch of the paper in the standard recording mode. 2. The ink-jet recording method. 4. The step of variably setting the scanning speed of the head in the high-quality recording mode sets the scanning speed of the head to approximately n times the scanning speed in the standard recording mode according to the value of n. The inkjet recording method according to any one of claims 1 to 3. 5. The ink jet recording method according to claim 1, wherein the value of n is 2 or 4. 6. The method according to claim 1, further comprising the step of keeping the flying amount of the ink particles from each nozzle constant, and setting the flying speed of the ink to a different value according to the nozzle. Item 7. The ink jet recording method according to the above item. 7. An ink jet recording method for recording image information on a recording medium by scanning a head having a plurality of nozzles for flying ink particles, wherein a flying amount of the ink particles from each nozzle is maintained constant, and An ink jet recording method, comprising: setting a flying speed of ink to a different value according to the condition; and recording each dot line on a recording medium by ink particles flying from a corresponding nozzle. 8. The ink jet recording method according to claim 7, wherein in the step of setting the flying speed of the ink to a different value according to the nozzle, a signal waveform for driving the nozzle is set to a different waveform according to the nozzle. 9. A head having a plurality of nozzles for flying ink particles when driven, and a scan for causing the head to scan in the main scanning direction and recording image information on a recording medium by the ink particles flying from the driven nozzles. Means, a means for feeding the paper in a sub-scanning direction orthogonal to the main scanning direction, and a standard recording mode in which one dot line is recorded on a recording medium by ink particles flying from the same nozzle.
In a high-quality recording mode in which recording is performed with higher image quality, the scanning unit is controlled so as to scan the head n times so that one dot line is recorded on a recording medium by ink particles flying from n nozzles. Means for selectively driving the nozzles; means for variably setting the line feed pitch p of the paper in the sub-scanning direction in accordance with the value of n in the high image quality recording mode; Means for variably setting the scanning speed of the head according to the value. 10. A head having a plurality of nozzles for flying ink particles when driven, means for scanning the head to record image information on a recording medium by ink particles flying from the driven nozzles, and each nozzle Setting means for keeping the flying amount of ink particles from the nozzle constant, and setting the flying speed of the ink to different values according to the nozzles, and recording each dot line on the recording medium by the ink particles flying from the corresponding nozzle. Means for driving the nozzle to perform the operation.