JP2003145805A - Recorder and recoding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To record high-quality images having smooth gray levels without increasing the number of recording heads. SOLUTION: In recording by scanning a carriage with the recording head 21 loaded for recording with the use of ink having additivity over a recording medium in a direction intersecting an arrangement direction of recording elements, a plurality of image data corresponding to different gradation levels are generated at an image processing part 3 from image data inputted from an interface 1, and stored into a plurality of buffer memories 50 respectively. The buffer memories are selected by a switch 51 for every scanning so that the plurality of image data are recorded overlapping with each other to the same recording region. The recoding head 21 is driven by a head driver 6 in accordance with image data stored in the selected buffer memories to record images.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus and a recording method, and more particularly to a carriage equipped with a recording head in which a plurality of recording elements for recording with a recording agent having an additive property are arranged in a predetermined direction. The present invention relates to a recording apparatus and a recording method for recording a gradation image by scanning on a recording medium in a direction intersecting the array direction of the recording elements.

[0002]

2. Description of the Related Art A recording device such as a printer, a copying machine, a facsimile or the like records an image of a dot pattern on a recording material (recording medium) such as paper or a plastic thin plate based on image information. It is configured. Such a recording apparatus can be classified into an inkjet method, a wire dot method, a thermal method, a laser beam method, and the like, depending on the recording method.

The ink-jet type recording apparatus of the above-mentioned type is constructed so that ink (recording liquid) droplets are ejected and ejected from the ejection port of the recording head, and the droplets are attached to a recording material for recording. The configuration is relatively simple.

In recent years, a large number of recording devices have been used, and high speed recording, high resolution, high image quality, low noise, etc. are required for these recording devices. The inkjet recording apparatus is used in a relatively small recording apparatus as a recording apparatus that meets such a demand, and is rapidly spreading.

The ink jet recording apparatus uses a recording head in which a plurality of ink ejection ports (nozzles) are arranged in an integrated manner in order to improve the recording speed, and the recording head ejects inks of different colors for each color. Many are equipped with a plurality of.

To meet the requirements for high resolution and high quality, halftone processing methods such as a dither method and an error diffusion method are used as a method for faithfully reproducing the gradation of image information in these ink jet recording apparatuses. There is.

In these gradation reproduction methods, the resolution of the recording apparatus is sufficiently high (about 1000 dots / inch or more).
In this case, excellent gradation recording is possible. However, when the resolution of the recording device is low (about 360 to 720 dots / inch), the recorded dots in the highlight portion are conspicuous,
Due to the discontinuity of the pixels, the image is likely to be rough.

Therefore, in order to further increase the number of gradations, a method of making the recording dots themselves multi-valued is used.

For example, there is known a method of controlling the voltage applied to the recording head or the pulse width to modulate the diameter of the recording dots attached to the recording material to obtain gradation. However, this method is highly dependent on the environment, the diameter of the recording dot is not stable, and the size of the smallest recordable dot is limited, so that it is difficult to reproduce the gradation stably.

There is a density modulation method that changes the density of dots in a matrix while the dot size remains constant, but a large area is required to increase the number of gradations, resulting in poor resolution.

Therefore, as a method of improving gradation characteristics and obtaining a high-density and high-gradation image by using an ink jet recording apparatus, a plurality of droplets are landed at substantially the same position on a recording material. A so-called multi-droplet method in which one dot (pixel) is formed and gradation is expressed by changing the number of droplets to be landed, or a plurality of inks having different densities are used, and at least two types of density A recording method in which gradations are reproduced by different recording dots, and a method in which the two are combined have been proposed and put into practical use.

FIG. 11 is a block diagram showing a control structure of a conventional general ink jet recording apparatus for performing multi-gradation recording using inks having different densities.

Reference numeral 1 in the drawing denotes an interface for receiving image data and commands from an external device such as a host computer, and outputs image information and character information to be recorded. A CPU 2 controls the entire apparatus. An image processing unit 3 creates an ejection pattern (bit plane) for recording a multi-tone image with ink droplets ejected from the recording head, based on the input image. A memory 4 is used as a work area for various programs, a temporary save area for error processing, and a work area for image processing.

Reference numerals 21-1 to 21-4 are recording heads for ejecting inks D1 to D4 having different densities, and 6-1 to 4 are head driving units for driving the recording heads 21-1 to 21-4. It has been placed. 5-1 to 4 are buffer memories for temporarily storing the ejection patterns for the respective print heads.

Reference numeral 11 is a carriage motor for moving the carriage 8, 10 is a carriage motor driving unit for driving the carriage motor 11, 13 is a recording medium conveying motor for conveying a recording medium, and 12 is a recording medium for driving the recording medium conveying motor 13. It is a conveyance motor drive unit.

In the ink jet recording apparatus having the above-mentioned structure, when the additivity of the ink is satisfied, the density ratio of the four kinds of inks D1, D2, D3 and D4 used is 1: 2: 4: 8. Then, 16 gradations from 0 to 15 can be expressed without density skipping by a combination of presence or absence of ejection of each of these inks.

[0017]

However, when a higher number of gradations is required, it is necessary to increase the number of recording heads and ink densities. Since the structure is such that the head reciprocates in the main scanning direction to perform recording, if the number of recording heads is increased, the size of the recording device in the main scanning direction becomes twice or more the width of the increased recording head. .

Further, as the number of print heads increases, the weight of the entire carriage on which the print heads are placed increases, so that a high-power carriage motor is required to obtain a predetermined scanning speed. Generally, a motor having a high output has a large size and is more expensive, which causes an increase in the size of the device and an increase in cost.

Further, as the number of recording heads increases, it becomes more difficult to adjust the relative position of each recording head. In the case of a so-called multi-droplet method in which a plurality of droplets are landed at substantially the same location on the recording medium to form one dot and the gradation is expressed by changing the number of the landed droplets as described above. , If the position of the recording head is not adjusted properly, the landing position of each ink will be misaligned, and the smoothness of gradation will be lost.
The image quality is reduced.

The present invention has been made in view of the above situation, and can be realized without increasing the number of recording heads.
An object of the present invention is to provide a recording apparatus and a recording method capable of increasing the number of gradations.

[0021]

In order to achieve the above object, a recording apparatus of the present invention is equipped with a recording head in which a plurality of recording elements for recording with a recording agent having an additive property are arranged in a predetermined direction. A recording device for performing recording by scanning a carriage on a recording medium in a direction crossing the arrangement direction of the recording elements, and generating a plurality of image data corresponding to different gradations from input image data. An image processing means, a plurality of storage means for respectively storing the plurality of image data, and one of the plurality of storage means for each scan so that the plurality of image data are recorded in the same recording area in an overlapping manner. And a recording control means for driving the recording head to record an image in accordance with the image data stored in the storage means selected by the selection means. That.

Further, in the recording method of the present invention which achieves the above-mentioned object, a carriage equipped with a recording head in which a plurality of recording elements for recording with a recording agent having an additive property are arranged in a predetermined direction is used. A recording method in which recording is performed by scanning on a recording medium in a direction intersecting with the arrangement direction of, and an image processing step of generating a plurality of image data corresponding to different gradations from input image data, Storing step of storing a plurality of image data in the plurality of storage means respectively, and selecting one from the plurality of storage means for each scanning so that the plurality of image data are recorded in the same recording area in an overlapping manner. And a recording control step of driving the recording head to record an image in accordance with the image data stored in the storage means selected in the selecting step.

That is, according to the present invention, a carriage equipped with a recording head in which a plurality of recording elements for recording with a recording agent having an additive property are arranged in a predetermined direction is arranged in a direction intersecting with the arrangement direction of the recording elements. When scanning and recording on a recording medium, a plurality of image data corresponding to different gradations are generated from input image data, and the plurality of image data are stored in a plurality of storage means, respectively. One of a plurality of storage means is selected for each scan so that the image data is recorded in the same recording area in an overlapping manner, and the recording head is driven according to the image data stored in the selected storage means to drive the image. To record.

In this way, multi-pass printing can be performed in which a plurality of image data corresponding to different gradations are overlaid and printed in the same printing area with one printing head using one printing agent. Then, a multi-tone image is recorded.

Therefore, the number of gradations can be increased without increasing the number of recording heads, and when recording the same number of gradations, the size of the device can be reduced and the cost can be reduced.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the following embodiments, an ink jet recording apparatus that records a transmission image using an additive ink / film system will be described as an example for simplification of description.

In the present specification, "recording" (sometimes referred to as "printing") means not only the formation of significant information such as characters and figures, but also the meaning of insignificance and the human sense of sight. In the case where an image, a pattern, a pattern, or the like is widely formed on a recording medium or the medium is processed, regardless of whether or not the medium is perceptible as described above.

Here, the "recording medium" is not limited to paper used in a general recording apparatus, but is widely used as cloth, plastic film, metal plate, glass, ceramics, wood,
It also includes leather and the like that can accept ink.

Further, "ink" (which may also be referred to as "liquid") is to be broadly construed in the same way as the definition of "recording (printing)", and when applied on a recording medium, A liquid that can be used for forming an image, a pattern, a pattern, or the like, processing a recording medium, or treating an ink (for example, solidifying or insolubilizing a coloring agent in the ink applied to the recording medium).

First, the additivity and the density of the ink used in the following embodiments will be described.

<Additiveness> Additive ink / film system means that when an ink jet recording apparatus records on a recording medium such as a film for recording a transparent image, the ink is ejected onto the same portion a plurality of times. (Overlapping) means that the transmission density increases in accordance with the total ejection amount of ink.

An example in which the additivity holds will be given. Canon BJ Transparency Film CF-301 is used as the recording medium, and dye-based C.I. I.
When a 2% solution of Direct Black 19 is uniformly recorded using an inkjet recording device, an image having a transmission density of 0.8D is obtained, and similarly, C.I. I. When a 1% solution of Direct Black 19 is uniformly recorded, an image having a transmission density of 0.4D is obtained. When the inks of these two types of density are overlapped and recorded, a transmission density of 1.2D can be obtained. 0 to 2.5 for this ink / film system
It has been confirmed by experiments that the additivity substantially holds in the range of D.

In such an additive ink / film system, the number of gradations that can be expressed can be significantly increased by overprinting a plurality of inks having different densities on the same pixel.

<Ink Density> In the ink jet recording apparatus of the present embodiment, four types of ink having different densities that satisfy additivity are used.

In this embodiment, the density ratios of the four types of inks D1, D2, D3 and D4 having different densities are 1: 2: 4 :.
As shown in FIG. 8, a multi-tone image can be formed by changing the combination of ink types for overprinting at the same location on the recording medium.

[First Embodiment] <Control Configuration> FIG. 1 is a block diagram showing a control configuration of a first embodiment of an ink jet recording apparatus according to the present invention. In FIG. 1, the same parts as those of the conventional device shown in FIG.

In this embodiment, four kinds of inks of similar colors but different densities are recorded at substantially the same location on the recording medium, and
This is a recording apparatus of the type that forms one dot and expresses gradation, and its structure will be described later with reference to FIG.

In FIG. 1, 50-1 and 50-2 are buffer memories for temporarily storing ejection patterns for the recording head 21-1, and 50-3 and 50-4 are temporary ejection patterns for the recording head 21-2. A buffer memory for storing in the recording head 50-5 and 50-6
Buffer memories 50-7 and 50-8 for temporarily storing ejection patterns for 1-3, the recording head 21-
4 is a buffer memory for temporarily storing the ejection pattern for No. 4. A selector 51 is controlled by the CPU 2 and selects a buffer memory for each recording head.

A storage medium 14 stores programs such as a control program and an error processing program for operating the recording device. The operations of this embodiment are all in accordance with this program. As the storage medium 14 for storing the program, ROM, FD, CD-
ROM, HD, memory card, magneto-optical disk, etc. can be used.

<Structure of Recording Apparatus> Next, the structure of the ink jet recording apparatus of this embodiment will be described. Figure 2
FIG. 2 is a schematic external view of the inkjet recording apparatus according to the present embodiment with a cover removed, viewed from above.

A plurality of recording heads 2 are provided on the carriage 8.
1-1 to 21-4 (hereinafter collectively referred to as 21). Each recording head 21 has an ejection port (nozzle) array for ejecting ink, and the ejection port array of each recording head 21 is installed at a predetermined interval. Each recording head 21-
Inks to the corresponding nozzle rows 1 to 21-4 are respectively supplied from the ink cartridges 22-1 to 22-4 containing the inks D1, D2, D3 and D4.

Control signals and the like to the recording head 21 are sent via the flexible cable 23. The recording medium 24, which is made of paper, a thin plastic plate, or the like, is sandwiched by the paper discharge rollers 25 via a transport roller (not shown), and is fed in the direction of the arrow as the transport motor 13 is driven. The carriage 8 is guided and supported by two parallel guide shafts 27. The carriage 8 is reciprocated along the guide shaft 27 by driving the carriage motor 11 via the drive belt 29. The linear encoder 28 is composed of, for example, a scale provided with slits at equal intervals and an optical sensor in order to output a pulsed signal in accordance with the movement of the carriage 8.

A heating element (electrical / thermal energy converter) that generates thermal energy for ink ejection is provided inside the ink ejection port (liquid path) of the recording head 21. With the timing of the output signal from the linear encoder 28, the heating element is driven based on the recording signal, and the ink droplets are ejected and adhered on the recording medium 24 in the order of the inks D1, D2, D3, and D4. Can be formed.

At the home position of the carriage 8 set outside the recording area, a recovery unit 32 having a cap portion 31 is installed. When recording is not performed, the carriage 8 is moved to the home position, the ink ejection port surface of the corresponding recording head 21 is sealed by the caps 31-1 to 31-4 of the cap portion 31, and this is caused by evaporation of the ink solvent. Prevents clogging due to ink sticking or foreign matter such as dust.

Further, the capping function of the cap portion 31 is an idle ejection for ejecting ink to the cap portion apart from the ink ejection port in order to eliminate ejection failure or clogging of the ink ejection port which is infrequently recorded. It is also used for the purpose of recovering the ejection of the ejection port that has caused ejection failure by operating a pump (not shown) in a capped state to suck ink from the ink ejection port. Reference numeral 33 denotes an ink receiver, which preliminarily ejects ink onto the ink receiver 33 when each of the recording heads 21-1 to 21-4 passes above the ink receiver 33 immediately before recording. Further, by disposing a blade and a wiping member (not shown) at a position adjacent to the cap portion,
It is possible to clean the surface of the ink ejection port.

<Recording Head> The detailed structure of the inside of the recording head is shown in Japanese Patent Application Laid-Open No. 7-125262, etc., and is well known.

With reference to FIG. 3, an example of the structure of the ink discharge port array and the image structure will be described. FIG. 3 is a diagram showing an example of ink ejection of the recording head as seen from the recording medium side. In the print head, 40-1 to 40-4 are ejection port arrays ejecting the inks D1 to D4, respectively, and the ejection port array of each head has a pitch of 600 (6
It has 256 discharge ports at 00 dpi).

In this embodiment, the case where the frequency at which the recording head ejects ink from the nozzle array is 10 kHz will be described. In the case of solid recording, 10000 ink droplets per second are ejected from the nozzle row of the recording head at a pitch of 600 dpi. The scanning speed of the carriage 8 at that time is about 423.3 mm / sec, and the short side of the A3 paper is scanned in about 0.7 seconds.

<Image Processing> Next, the flow of image processing for generating an ejection pattern from an input image will be described with reference to FIG.

The process described below can be configured to be executed by hardware (image processing board) or software. When executing by software, the image processing unit 3 does not exist, the image processing program is stored in the control program group, and C
By executing this program under the control of PU2, the following processes are executed.

When the user gives an instruction to record a desired image from the operation unit, the data reading 100 reads the data via the interface 1 and stores it in the memory 4. In the gamma correction processing 101, image data is extracted from this data, the CV value for each pixel is converted into a signal CD value representing the density using the gamma correction conversion table 102, and stored in the memory 4. In the first stage processing 103, the image in the memory 4 is subjected to processing such as enlargement interpolation processing, image rotation and formatting.

In the target pixel selection 104, one pixel in the memory area to be processed is selected and the density data CD value is obtained. In the ink distribution process 105, reference is made to the ink distribution table 106 to obtain combination data of inks to be overlaid, a binary signal of ejection or non-ejection of ink of each density is determined, and this is further determined according to a predetermined rule. The ejection and non-ejection binary signals of each head are determined, and the ejection pattern 107 for each head is generated.

<Recording Operation> Next, the recording operation in the first embodiment will be described with reference to FIGS. 5 and 6.
5 and 6, the number of ejection ports of the recording head is 16 and the recording width is 8 dots for simplification of description.

FIGS. 5A and 5B are ejection patterns of one recording head 21-1, respectively, and the images shown in FIG. 5C are generated by superimposing the respective patterns. It The process of generating the image of FIG. 5C will be described with reference to FIGS. 6A to 6D.

First, the CPU 2 transfers the image data input from the host computer 1 to the image processing section 3 and performs the above-described image processing to obtain eight ejection patterns. The CPU 2 transfers the generated discharge patterns to the buffer memories 50-1 to 50-8 so that the discharge patterns can be transferred to the print heads corresponding to the respective densities.

Regarding the subsequent processing, one recording head 2
The image generated by 1-1 will be described in detail.

First, the ejection pattern shown in FIG. 5A is transferred to the buffer memory 50-1, and the ejection pattern shown in FIG. 5B is transferred to the buffer memory 50-2.

Next, the CPU 2 has a buffer memory 50-1 for the recording head 21-1, a buffer memory 50-3 for the recording head 21-2, and a recording head 21-.
For 3, buffer memory 50-5, recording head 2
The selector 51 is controlled so that the buffer memories 50-7 are selected for 1-4.

As shown in FIG. 6A, the CPU 2 moves the recording medium 24 upward in the drawing by a distance corresponding to 8 which is half the 16 effective ejection ports of the recording head 21-1.
Perform sub-scan. The recording head 21-1 is shown in FIG.
The first main scan for moving to the right in (a) is performed. In the first main scan, the ejection pattern of the area shown in (1) of FIG. 5A among the ejection patterns of the buffer memory 50-1 is transferred to the head driver 6-1 and the recording head 21 follows the ejection pattern. -1 is driven, and the recording of the area shown in (1) of FIG. 6A is performed.

When the first main scan is completed, the CPU 2 carries out a second sub-scan for moving the recording medium 24 upward in the figure by a distance corresponding to eight ejection ports as shown in FIG. 6B. Then, the CPU 2 records the buffer memory 50-2 for the recording head 21-1, the buffer memory 50-4 for the recording head 21-2, the buffer memory 50-6 for the recording head 21-3, and the recording. The selector 51 is controlled so that the buffer memory 50-8 is selected for the head 21-4.

The second main scan for moving the recording head 21-1 to the right in FIG. 6B is performed. In this second main scan,
Of the ejection pattern of the buffer memory 50-2, the area (2) in FIG. 5B is transferred to the head driver 6-1, and the recording head 21-1 is driven according to the ejection pattern to perform recording.

At this time, the dots in the area (1) of FIG. 6A recorded in the first main scan and the area of (2) in FIG. 6B recorded in the second main scan. In FIG. 6, dots are overlapped, and the density is double that of the area (3) in FIG. 6B which is not printed in the second main scan.

Similarly, in the third main scan shown in FIG. 6C, the ejection pattern in the area (3) of FIG. 5A of the print buffer 50-1 is recorded, and the discharge pattern of FIG. FIG. 5 of the print buffer 50-2 in the fourth main scan shown in FIG.
By printing the discharge pattern in the area (4) of (b) of FIG. 5 and switching the print buffer for each effective main scan, one printing is performed as shown in (c) of FIG. Images with two gradations can be expressed with the recording head.

Here, the recording operation of this embodiment will be described again with reference to the flowchart of FIG.

First, the image processing unit 3 processes the image data input through the interface 1 (step S10).
1) The two ejection patterns corresponding to the respective print heads obtained as the processing result are stored in the buffer memories 50-1 to 50-8, respectively (step S102).

Next, the selector 51 is controlled to select the discharge pattern to be printed by scanning (step S103), and the transport motor 13 is driven via the print medium transport motor driver 12.
Is driven to perform sub-scanning (step S104), and the carriage motor 11 is driven via the carriage motor driver 10.
And the recording head 21 via the head driver 6 to execute main scanning (step S10).
5).

Here, it is checked whether or not all areas have been recorded (step S106), and if there are areas that still remain,
The process after step S103 is repeated to record the next area.

Table 1 below shows the correspondence between the discharge pattern, the buffer memory, the printing area and the printing result, which are used in each scan in the present embodiment.

[0069]

[Table 1]

That is, the density ratio of the ink used in the four recording heads 21-1 to 21-4 in this embodiment is D1:
When D2: D3: D4 = 1: 2: 4: 8, two ejection patterns are prepared for each recording head, so that a total of eight ejection patterns can be overlapped. Therefore,
0 to 3 depending on whether or not each of these inks is ejected
It is possible to express gradations up to 0 (= (1 + 2 + 4 + 8) × 2) without density skipping.

[Second Embodiment] The second embodiment of the ink jet recording apparatus according to the present invention will be described below. In the following description, description of the same parts as those in the first embodiment will be omitted, and the description will focus on the characteristic parts of the second embodiment.

The second embodiment is also an ink jet recording apparatus similar to the first embodiment, but in this embodiment, the ejection pattern is masked in order to prevent image streaks.
The number of scans is increased.

<Control Configuration> FIG. 7 is a block diagram showing the control configuration of the second embodiment of the ink jet recording apparatus of the present invention, similar to FIG. In FIG. 7, the same parts as those in the first embodiment shown in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 7, 52-1 and 52-2 are mask memories for storing masks for the ejection patterns of the recording heads 21-1 to 21-4. A selector 53 is controlled by the CPU 2 and selects a mask memory.
Reference numerals 54-1 to 54-4 are arithmetic units for performing a logical product of the ejection pattern transferred from the buffer memory selected by the CPU 2 and the mask pattern transferred from the mask memory selected in the same manner. 6
-1 to 4 are connected.

With such a configuration, the result of the logical product of the discharge patterns stored in the buffer memories 50-1 to 50-8 and the mask pattern stored in 52-1 or 52-2 is the result of the head drivers 6-1 to 4-1. And is recorded by each of the corresponding recording heads 21-1 to 21-4.

<Recording Operation> Next, the recording operation in the second embodiment will be described with reference to FIGS. 8 to 10B. In addition,
In the following, in order to simplify the explanation, the number of ejection ports of the recording head is 16 and the paper width is 8 dots.

8A and 8B are ejection patterns of the recording head 21-1, respectively, and the images shown in FIG. 8C are generated by superimposing the respective patterns. 9A shows the mask pattern stored in the mask memory 52-1 of FIG. 2, and FIG. 9B shows the mask pattern stored in the mask memory 52-2 of FIG. In the mask pattern of FIG. 9, the white portion indicates that the ejection is effective, and the black portion indicates that the ejection is masked, which are complementary patterns for masking 1/2 of each pixel.

The process of generating the image shown in FIG. 8C will be described with reference to FIGS. 10A and 10B.

First, the CPU 2 transfers the image data input via the interface 1 to the image processing unit 3, and
Image processing as described in the embodiment of
Eight discharge patterns are obtained. The CPU 2 transfers the generated ejection patterns to the buffer memories 50-1 to 50-8 so as to transfer them to the recording heads corresponding to the respective densities.

The subsequent processing will be described in detail, focusing on the image generated by one recording head 21-1.

First, the discharge pattern shown in FIG. 8A is transferred to the buffer memory 50-1, and the discharge pattern shown in FIG. 8B is transferred to the buffer memory 50-2.
Remembered.

Next, the CPU 2 has a buffer memory 50-1 for the recording head 21-1, a buffer memory 50-3 for the recording head 21-2, and a recording head 21-.
For 3, buffer memory 50-5, recording head 2
The selector 51 is controlled so that the buffer memories 50-7 are selected for 1-4. Also, CP
U2 controls the selector 53 so as to select the mask memory 52-1.

Since the CPU 2 has two ejection patterns and the mask amount of the mask pattern is 1/2, as shown in (a) of FIG. 10A, 1/4 of the 16 effective ejection ports of the recording head 21-1. The first sub-scan for moving the recording medium 24 upward in the drawing is performed by a distance corresponding to four (= 1 / (2 · 2)). Then, the first main scan for moving the recording head 21-1 to the right in the drawing is performed. In the first main scan, the logical product of the ejection pattern of the ejection pattern of the buffer memory 50-1 in the region (1) of FIG. 8A and the mask pattern of FIG. Then, the data is transferred to the head driver 6-1 and the recording head 21-1 is driven to perform recording as shown in FIG. 10A (a).

When the first main scan is completed, the CPU 2 executes the process shown in FIG.
As shown in (b) of A, the second sub-scanning for moving the recording medium 24 upward in the drawing by a distance corresponding to four ejection ports is performed. The CPU 2 then uses the buffer memory 50-2 for the recording head 21-1, the buffer memory 50-4 for the recording head 21-2, and the recording head 21-3.
For the buffer memory 50-6, the recording head 21
For -4, the selector 51 is controlled so that the buffer memory 50-8 is selected. Also, CPU
2 is a selector 5 so as to select the mask memory 52-2
Control 3

Then, the second main scan for moving the recording head 21-1 to the right in FIG. 10A (b) is performed.
In the second main scan, the logical product of the discharge pattern of the discharge pattern of the buffer memory 50-2 in the area (2) of FIG. 8B and the mask pattern of FIG. −1, the data is transferred to the head driver 6-1 and the recording head 21-1 is driven to drive the recording head 21-1.
Recording as shown in FIG.

Similarly, in the third main scan shown in (c) of FIG. 10A, the discharge pattern in the area (3) of (a) of FIG. 8 of the print buffer 50-1 and (a) of FIG. 10A, the discharge pattern of the area (4) of FIG. 8B of the print buffer 50-2 in the fourth main scan shown in FIG. b) AND with mask pattern, ..., Eighth main scan shown in (h) of FIG. 10B, and discharge pattern and area of area (8) of FIG. 8B of print buffer 50-2 As shown in FIG. 9B, the logical product with the mask pattern is switched to switch the print buffer and the mask pattern for each effective main scan, and the result of the logical product operation of both is recorded. As shown in (c), one head can express an image with two gradations. The flowchart of the recording operation in this embodiment is the same as the flowchart of FIG. 12 described in regard to the first embodiment, but in step S103, in addition to the selector 51, the selector 53 is also controlled,
Select the mask pattern to use in each scan.

Table 2 below shows the correspondence between the discharge pattern, the buffer memory, the mask memory, the recording area and the recording result, which are used in each scan in the present embodiment.

[0088]

[Table 2]

[Other Embodiments] In the embodiments described above, a transparent image is recorded on a film by an inkjet recording device, but the present invention is limited to an inkjet recording device using such an ink / film. However, the present invention can be applied to all recording devices capable of recording a gradation image on an appropriate recording medium using an additive ink (recording agent).

In the above-described embodiment, one recording head has two
Although the discharge patterns stored in the three buffer memories are switched and recorded, the present invention is not limited to this.
By making it possible to switch a plurality of buffer memories with respect to one recording head, it is possible to record two or more ejection patterns with one ink jet.

Further, in the above embodiment, the selector selects the buffer memory for mechanical recording, but the method of selecting or switching the buffer memory is not limited to this. For example, the buffer memory and the head driver may be selected. It is also possible to use a bus connection between them, select a buffer memory by an address, and perform DMA transfer to the head driver.

Further, although the pseudo halftone processing is not performed on the image data in the above embodiment, the number of gradations can be further increased by performing the pseudo halftone processing such as dither and error diffusion. is there.

In addition, in the above embodiment, the unidirectional recording with a single scanning direction was described, but it is also possible to perform so-called bidirectional recording, that is, recording in both reciprocating directions. Is.

Further, in the second embodiment, the number of ejection patterns is two and the mask amount of the mask pattern is 1/2. However, N ejection patterns (N: integer) and the mask amount is 1 / M. (M: integer), and the sub-scanning amount at that time may be a distance corresponding to 1 / (N · M) of the number of effective ejection openings of the print head.

In the above-described embodiments, particularly in the ink jet recording system, a means (for example, an electrothermal converter or a laser beam) for generating heat energy as energy used for ejecting ink is provided, and High density and high definition recording can be achieved by using a method of causing a change in ink state by energy.

Regarding the typical structure and principle thereof, see, for example, US Pat. Nos. 4,723,129 and 4740.
What is done using the basic principles disclosed in 796 is preferred. This method can be applied to both the so-called on-demand type and continuous type, but especially in the case of the on-demand type, liquid (ink)
By applying at least one drive signal to the electrothermal transducer arranged corresponding to the sheet or liquid path in which is stored, which corresponds to the recorded information and gives a rapid temperature rise exceeding nucleate boiling. Since the electrothermal converter is caused to generate heat energy to cause film boiling on the heat-acting surface of the recording head, as a result, bubbles in the liquid (ink) corresponding to the drive signal in a one-to-one relationship can be formed. It is valid.

Due to the growth and contraction of the bubbles, the liquid (ink) is ejected through the ejection openings to form at least one droplet. It is more preferable to make this drive signal into a pulse shape, because the bubble growth and contraction are immediately and appropriately performed, so that the ejection of the liquid (ink) with excellent responsiveness can be achieved.

Suitable pulse-shaped drive signals are those described in US Pat. Nos. 4,463,359 and 4,345,262. If the conditions described in US Pat. No. 4,313,124 of the invention relating to the rate of temperature rise on the heat acting surface are adopted, more excellent recording can be performed.

As the constitution of the recording head, in addition to the combination constitution of the discharge port, the liquid passage, and the electrothermal converter (the linear liquid passage or the right-angled liquid passage) as disclosed in the above-mentioned respective specifications, The present invention also includes the configurations described in US Pat. No. 4,558,333 and US Pat. No. 4,459,600, which disclose configurations in which the heat-acting surface is arranged in a bending region. In addition, Japanese Unexamined Patent Publication No. 59-123670 discloses a structure in which a common slot is used as a discharge portion of a plurality of electrothermal converters, and an opening for absorbing a pressure wave of thermal energy is discharged. A configuration based on Japanese Patent Application Laid-Open No. 59-138461, which discloses a configuration corresponding to each section, may be adopted.

In addition to the cartridge type recording head in which the ink tank is integrally provided in the recording head itself described in the above embodiment, the recording head itself is electrically connected to the apparatus main body by being mounted. A replaceable chip-type recording head that enables various connections and supply of ink from the apparatus main body may be used.

Further, it is preferable to add recovery means for the recording head, preliminary means, etc. to the structure of the recording apparatus described above because the recording operation can be made more stable. Specific examples thereof include capping means for the recording head, cleaning means, pressurizing or sucking means, electrothermal converters or heating elements other than these, or preheating means by a combination thereof. Further, provision of a preliminary ejection mode for performing ejection different from recording is also effective for stable recording.

Further, the recording mode of the recording apparatus is not limited to the recording mode of only the mainstream color such as black, but the recording head may be integrally formed or a plurality of combinations may be used. Alternatively, the device may be provided with at least one of full-color mixed colors.

In the above-described embodiments, the explanation is made on the premise that the ink is a liquid, but even if the ink solidifies at room temperature or below, one that softens or liquefies at room temperature is used. Or, in the inkjet method, it is general that the temperature of the ink itself is adjusted within a range of 30 ° C. or higher and 70 ° C. or lower to control the temperature of the ink so that the viscosity of the ink is in a stable ejection range.
It suffices that the ink is in a liquid state when the use recording signal is applied.

In addition, in order to positively prevent the temperature rise due to thermal energy from being used as the energy for changing the state of the ink from the solid state to the liquid state,
Alternatively, in order to prevent the ink from evaporating, an ink that solidifies in a standing state and liquefies by heating may be used. In any case, by applying heat energy, such as ink that is liquefied by applying heat energy according to the recording signal and liquid ink is ejected, or that begins to solidify when it reaches the recording medium. The present invention can be applied to the case where an ink having a property of being liquefied for the first time is used.

In this case, the ink is described in JP-A-54-5.
6847 or Japanese Unexamined Patent Publication No. 60-71260, such that it is opposed to the electrothermal converter in the state where it is held as a liquid or solid in the recesses or through holes of the porous sheet. May be In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

Even when the present invention is applied to a system composed of a plurality of devices (for example, host computer, interface device, reader, printer, etc.), a device composed of one device (for example, a copying machine, a facsimile device) Etc.)

Further, an object of the present invention is to supply a storage medium having a program code of software for realizing the functions of the above-described embodiments to a system or apparatus, and to supply a computer (or CPU) of the system or apparatus.
It is needless to say that it can be achieved by reading and executing the program code stored in the storage medium.

In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the storage medium storing the program code constitutes the present invention.

A storage medium for supplying the program code is, for example, a floppy disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD.
-R, magnetic tape, non-volatile memory card, ROM, etc. can be used.

Moreover, not only the functions of the above-described embodiments are realized by executing the program code read by the computer, but also the OS (operating system) running on the computer based on the instructions of the program code. It is needless to say that this also includes a case where the above) performs a part or all of the actual processing and the processing realizes the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written in the memory provided in the function expansion board inserted into the computer or the function expansion unit connected to the computer, based on the instruction of the program code, It goes without saying that a case where the CPU or the like included in the function expansion board or the function expansion unit performs some or all of the actual processing and the processing realizes the functions of the above-described embodiments is also included.

When the present invention is applied to the above storage medium, the storage medium stores the program code corresponding to the above-described flow (shown in FIG. 4 and / or FIG. 12) and flow chart. .

[0113]

As described above, according to the present invention, 1
Multi-pass printing is performed by a single print head that uses different types of printing agents so that multiple image data corresponding to different gray levels are overlaid and printed in the same printing area, and a multi-tone image is printed. To be done.

Therefore, the number of gradations can be increased without increasing the number of recording heads, and when recording the same number of gradations, the size of the apparatus can be downsized and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a control configuration of a first embodiment of a recording apparatus of the present invention.

FIG. 2 is a top view showing a main configuration of a mechanical configuration of the embodiment shown in FIG.

FIG. 3 is a diagram showing an arrangement of ink ejection port arrays of the recording head in the embodiment of FIG.

FIG. 4 is a flowchart illustrating an operation of image processing in the embodiment of FIG.

FIG. 5 is a diagram showing ejection patterns and recording results according to the first embodiment.

FIG. 6 is a diagram for explaining a recording operation according to the first embodiment.

FIG. 7 is a block diagram showing a control configuration of a second embodiment of a recording apparatus of the present invention.

FIG. 8 is a diagram showing image data and a recording result in the second embodiment.

FIG. 9 is a diagram showing a mask pattern according to a second embodiment.

FIG. 10A is a diagram for explaining a recording operation in the second embodiment.

FIG. 10B is a diagram for explaining the recording operation in the second embodiment.

FIG. 11 is a block diagram showing a control configuration of a conventional recording apparatus.

FIG. 12 is a flowchart of a recording operation according to the first embodiment.

[Explanation of symbols]

1 interface 2 CPU 3 Image processing section 4 memory 5,50 buffer memory 6 head driver 8 carriage 10 Carriage motor drive 11 Carriage motor 12 Recording medium transport motor drive unit 13 Conveyor motor 14 storage media 21 recording head 22 ink cartridges 23 Flexible cable 24 recording media 27 Guide shaft 28 Linear encoder 29 drive belt 31 Cap 32 Recovery Unit 33 Ink tray 51, 53 selector switch 52 Mask memory 54 arithmetic unit

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Claims (21)

[Claims] 1. A carriage equipped with a recording head in which a plurality of recording elements for recording with a recording agent having an additive property are arranged in a predetermined direction on a recording medium in a direction intersecting the arrangement direction of the recording elements. A recording device for scanning and recording, comprising image processing means for generating a plurality of image data corresponding to different gradations from input image data, and a plurality of storages for respectively storing the plurality of image data. Means for selecting one of the plurality of storage means for each scan so that the plurality of image data are recorded in the same recording area in an overlapping manner; and the storage means selected by the selection means. A recording control unit that drives the recording head to record an image in accordance with the stored image data. 2. The recording apparatus according to claim 1, wherein the selection unit selects the plurality of storage units in a predetermined order. 3. The recording apparatus according to claim 1, wherein the number of times of scanning each recording area is equal to the number of the storage means. 4. A mask means for masking the image data stored in the selected storage means with a predetermined pattern is further provided, and the recording control means controls the recording head according to the image data masked by the mask means. The recording apparatus according to claim 1, wherein the recording apparatus is driven to record an image. 5. The mask means comprises a plurality of mask memories for storing a plurality of complementary mask patterns, respectively.
The recording apparatus according to claim 4, further comprising a mask selecting unit that selects a mask memory used for each scan. 6. When the number of the storage means is N and the number of the mask memories is M, the number of times each recording area is scanned is N.
The recording device according to claim 4 or 5, wherein the recording device is xM. 7. A recording head having a plurality of recording heads, wherein the image processing means generates the plurality of image data for each recording head and stores the plurality of image data for each recording head. The recording apparatus according to claim 1, further comprising a plurality of storage units. 8. The recording apparatus according to claim 7, wherein the plurality of recording heads use recording agents having different densities. 9. The recording according to claim 1, wherein the recording agent is ink, and the recording head is an ink jet recording head that ejects ink to perform recording. apparatus. 10. The recording head is a recording head which ejects ink by utilizing thermal energy, and is provided with a thermal energy converter for generating thermal energy applied to the ink. Item 10. The recording device according to item 9. 11. A carriage equipped with a recording head in which a plurality of recording elements for recording with an additive recording agent are arranged in a predetermined direction on a recording medium in a direction intersecting the arrangement direction of the recording elements. A recording method of performing scanning by recording, comprising an image processing step of generating a plurality of image data corresponding to different gradations from input image data, and the plurality of image data in the plurality of storage means, respectively. A storing step of storing, a selecting step of selecting one from the plurality of storage means for each scan so that the plurality of image data are recorded in the same recording area in an overlapping manner, and a selecting step selected in the selecting step A recording control step of driving the recording head to record an image in accordance with the image data stored in the storage means. 12. The recording method according to claim 11, wherein, in the selecting step, the plurality of storage units are selected in a predetermined order. 13. The method according to claim 11, wherein the number of times of scanning each recording area is equal to the number of the storage means.
The recording method described in 2. 14. A masking step of masking the image data stored in the selected storage means with a predetermined pattern, wherein the recording head is controlled by the recording head according to the image data masked in the masking step. The recording method according to claim 11 or 12, wherein the image is recorded by driving. 15. The masking step includes a step of preparing a plurality of mask memories for storing a plurality of complementary mask patterns, and a mask selecting step of selecting a mask memory to be used for each scan. Claim 1 characterized by
The recording method described in 4. 16. When the number of the storage means is N and the number of the mask memories is M, the number of times each recording area is scanned is
The recording method according to claim 14, wherein the recording method is N × M. 17. A plurality of recording heads are used, the plurality of image data are generated for each recording head in the image processing step, and the plurality of images are generated for each recording head in the storing step. 17. The recording method according to claim 11, wherein data is stored in each of the plurality of storage units. 18. The recording method according to claim 17, wherein the plurality of recording heads use recording agents having different densities. 19. The recording method according to claim 11, wherein ink is used as the recording agent, and the recording is performed by ejecting the ink from the recording head. 20. A computer program for realizing the recording method according to claim 11 by a computer. 21. A storage medium storing the computer program according to claim 20.