JPH082088A - Ink jet recording method and apparatus - Google Patents

Abstract

PURPOSE:To perform high-grade recording of high resolving power without relying on input data. CONSTITUTION:In a first recording mode emitting a relatively large amt. of ink low in resolving power to perform recording, a liquid droplet emitting and recording condition of low resolving power is set (301, 302) and, in a second recording mode emitting a relatively small amp. of ink of high resolving power to perform recording, resolving power enhancing treatment and smoothing/ decimation treatment are performed and a liquid droplet emitting and recording condition of low resolving power is set (304-307) and the recording control corresponding to the set recording mode is performed (303).

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 a recording apparatus for forming characters and images by depositing ink droplets on a recording medium, and particularly to ink jet recording suitable for high resolution recording or high gradation recording. The present invention relates to a method and a recording method.

The present invention is applicable to ordinary paper, special paper, cloth, OHP.
It can be applied to all devices that use recording media such as paper.
Specific applicable devices include printers, copying machines, facsimiles, and the like.

[0003]

2. Description of the Related Art Ink jet recording has low noise, low running cost, easy miniaturization of an apparatus, and easy colorization.
And so on. Color inkjet recording uses three color inks of cyan (C), magenta (M), and yellow (Y), or black (B) for these three colors.
It is carried out using four color inks containing k). In addition, there are also some that perform color recording using inks such as green (G), red (R), and blue (B).

In conventional ink jet recording, in order to obtain an image without ink bleeding, it was necessary to use a special paper having an ink absorbing layer. In recent years, due to improvements in ink, a method has been put into practical use, which is suitable for printing on "plain paper" that is used in large quantities in printers, copying machines and the like.

However, at present, the quality of high-resolution recording on "plain paper" is still insufficient. The cause is largely due to ink bleeding on the recording medium.

[0006] Comparing the case of recording on a special paper designed in consideration of reducing the ink bleeding with the case of recording on a plain paper with the ink droplets of the same volume, the bleeding on the plain paper is naturally a special case. It is larger than paper. Therefore, high-resolution recording on plain paper is more disadvantageous than dedicated paper. Therefore,
Recording on plain paper may be performed with ink droplets having a smaller volume.

Bleeding can also be reduced by reducing the average amount of ink per unit area on plain paper. However, in this case, there are disadvantages that the recording characteristics are deteriorated during gray gradation recording, the hue of the original image is changed particularly during color recording, and the resolution of the recorded image is reduced.

On the other hand, there are many known techniques relating to smoothing processing as a pseudo method for increasing the resolution. For example, US Pat. No. 4,809,021 describes smoothing recording using dots of three or more sizes. This is a technique for smoothly recording characters, for example, using dots of various sizes. This method requires preparation for always recording dots of various sizes.
For example, a recording head having various nozzle diameters and a portion for converting an image to be recorded into data corresponding to each nozzle diameter are required.

Also, there are many proposals regarding edge enhancement as a method for improving the image quality. For example, JP-A 1-21
Japanese Patent No. 2176 discloses that an image signal is second-order differentiated to calculate an original image signal as smoothed data to emphasize an edge portion. This is a proposal for constant-resolution edge enhancement. There are many other proposals regarding edge enhancement, and there are many known means.

As described above, in the conventional ink jet recording, various proposals have been made to improve the image quality.

[0011]

However, in the conventional ink jet recording, it was not possible to obtain a high resolution and high quality image according to various input data.

Therefore, an object of the present invention is to provide an ink jet recording method and a recording apparatus which can perform high resolution and high quality recording regardless of input data.

A further object of the present invention is to provide an ink jet recording method and recording apparatus capable of performing high resolution recording even on plain paper.

[0014]

In order to achieve the above object, the present invention provides an ink jet recording method for performing recording using a recording head for ejecting ink, in which a relatively large amount of ink is ejected at low resolution. A first recording mode for performing recording and a second recording mode for performing recording by ejecting ink having a high resolution and a relatively small amount are set, and depending on the set first or second recording mode. And converting the input data into recording data for driving the recording head, and performing recording control according to the recording mode set by the setting means based on the converted recording data. .

According to the present invention, in an ink jet recording apparatus for recording by using a recording head for ejecting ink, a first recording mode for ejecting and recording a relatively large amount of ink with low resolution, Input according to a setting unit that sets a second recording mode for performing recording by ejecting ink with a high resolution and a relatively small amount, and according to the first or second recording mode set by the setting unit. Converting means for converting the data into recording data for driving the recording head; and recording control means for performing recording control according to the recording mode set by the setting means based on the recording data converted by the converting means. It is characterized by having.

[0016]

According to the above construction, the input data can be converted into the recording data for driving the recording head according to the recording mode, and the recording according to the recording mode set based on the converted recording data can be performed. Therefore, high-quality and high-quality recording can be performed regardless of the input data.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings.

(Embodiment 1) High resolution recording of low resolution data FIG. 1 is a perspective view of an ink jet recording apparatus as an embodiment to which the present invention can be applied. The recording medium 106 inserted into the paper feeding position of the recording apparatus 100 is conveyed to the recordable area of the recording head unit 103 by the feed roller 109. A metal platen 108 is provided below the recording medium in the recordable area. Carriage 101
Is configured to be movable in a direction defined by the two guide shafts 104 and 105, and reciprocally scans the recording area. The carriage 101 is equipped with a recording head unit 103 including an ink tank for supplying four color inks and a recording head for ejecting those inks.
The four color inks provided in the inkjet recording apparatus of this embodiment are black (Bk), cyan (C), magenta (M), and yellow (Y). Reference numeral 107 denotes a switch and a display panel, which display various recording mode settings and the state of the recording apparatus.

FIG. 2 is a perspective view of the recording head unit. Black ink tank 2 containing black ink
The color ink tanks 20 in which 1 and the other three color inks are integrally stored are connected to the recording heads 102 by pipes, and the inks in the respective tanks are supplied to the recording heads 102. Bk,
There is a discharge port array 23 composed of a plurality of discharge ports corresponding to each color of C, M, and Y. The number of ejection openings for each color is 32, respectively. The intervals of 32 discharge ports of each color are arranged linearly at a density of 360 dpi, which makes the dot pitch about 70 μm. Further, the ejection port arrays of each color are arranged at intervals of 8 dot pitch. The ejection ports of each color are arranged so that Bk, C, M, and Y are recorded in this order.

In the ink jet recording apparatus of this embodiment, the electric / thermal converters are arranged corresponding to the ink liquid paths (nozzles), and a drive signal corresponding to recording information is applied to the electric / thermal converters so that the nozzles A so-called bubble jet recording method, in which ink is ejected from the recording medium, is adopted.

FIG. 3 is an enlarged sectional view near the electrothermal converter of the recording head, and FIG. 4 is an enlarged front view near the electrothermal converter of the recording head.

As shown in FIG. 4, the heating element 30, which is an electric / heat converting element of the recording head, has two heating elements H1 and H2, each of which is capable of independently heating all nozzles.
Is provided.

At the time of normal low resolution recording, 360 dpi
Record at the recording density of. At the time of ink ejection at this time, H1 and H2 corresponding to each ejection port generate heat at the same time. The ink in the nozzle that is rapidly heated by the heat generated by the heating elements H1 and H2 forms bubbles due to film boiling, and the pressure of bubble generation causes ink droplets 35 to form ink droplets 35 as shown in FIG.
The ink is ejected toward 1 to form characters and images on the recording medium. In this case, the volume of each color ink droplet discharged is about 40 ng.

On the other hand, at the time of high resolution recording, only the H1 of each nozzle is controlled to generate heat, and the volume of the ink droplet of each color ejected is about 20 which is smaller than that at the time of low resolution recording.
ng.

As described above, the recording head capable of ejecting different volumes from the same nozzle was used to perform high resolution recording using only a small volume of ink. In order to obtain ejection of different ink volumes, in addition to the method of using two electrothermal converters for each nozzle as described above, for example, the power applied to the electrothermal converters during ink ejection or ink It is also possible to control the temperature of, and any method can be applied in the present invention.

Each of the ejection ports 23 is provided with an ink liquid passage communicating with the ejection port, and a common liquid for supplying ink to these liquid passages is provided behind the portion where the ink liquid passage is provided. A chamber 32 is provided. A heating element 30 (H1 and H2 shown in FIG. 4), which is an electrothermal converter, generates thermal energy used to eject ink droplets from the ejection ports in the ink liquid paths corresponding to the ejection ports. Also, electrode wiring for supplying electric power thereto is provided. The heating element 30 and the electrode wiring are formed on the substrate 33 made of silicon or the like by a film forming technique. A protective film 36 is formed on the heating element 30 so that the ink and the heating element do not come into direct contact with each other. Further, by stacking the partition wall 34 made of resin or glass material on this substrate, the ejection port, the ink liquid passage, the common liquid chamber, and the like are formed.

As described above, since the recording head using the electrothermal converter uses bubbles formed by applying thermal energy when ejecting ink droplets, it is commonly called a bubble jet recording head.

Here, in the present embodiment, the volume of the ink droplet of each color ejected is set to about 40 ng at the time of ordinary low resolution recording of 360 dpi, and the volume of the ink droplet of each color ejected at the time of high resolution recording is set to about 40 ng. The volume was about 20 ng.
The reason for this is shown below.

This is because the average maximum ink absorption amount per pixel at 360 dpi on plain paper is about 80 ng.
It was decided from that. When recording the secondary colors of red (R), green (G), and blue (B),
Two dots of Y, M, and C ink droplets are mixed. For this reason,
The volume of each color ink drop is set to about 40 ng, which is half the maximum absorption amount, so as not to overflow on plain paper.

Next, at the time of high resolution recording of 720 dpi,
Originally, the volume of ink of 1 dot should be set to 10 ng, which is ¼ of 360 dpi recording, and 4 dots should be recorded in the area where 1 dot was recorded during 360 dpi recording. However, it is quite possible to mass-produce a multi-nozzle recording head in which a plurality of nozzles can be stably ejected to a desired recording position at a desired timing with a stable discharge of about 10 ng of an ink droplet, which is a quarter. Is difficult. This is because the processing accuracy of the nozzle and the clogging of fine dust reduce productivity. Further, it is technically difficult to achieve both ink droplet ejection of about 40 ng during normal recording and ink droplet ejection of about 10 ng for high-density recording in the current production technology. Setting the volume to 20 ng is more practical than setting the volume of the ejected ink droplet to 10 ng, and by applying the present invention, it is possible to perform high-resolution recording excellent in image quality.

Further, due to future production technology advances, 10
In the case where a recording head capable of stably ejecting ink droplets having a volume as small as 5 ng or even 5 ng can be produced, by applying the present invention, recording with higher resolution becomes possible. Become.

To determine the average maximum ink absorption amount per unit area on the recording medium, usually, the worst value is set when the area in which a specific area is uniformly filled is recorded. This is because the ink in the uniformly filled portion can permeate only inside the recording medium.
On the other hand, in the vicinity of the edge portion, the ink can overflow and permeate to the outside of the recording area, which is not the limitation.

On the other hand, when a character or an image is recorded, it is generally known that if the edge portion is recorded more densely, the quality is good.

Therefore, the ink recording amount per unit area with 360 dpi corner as the unit area is set to a maximum of 80 ng for a single color at an edge portion (160 ng for two colors) and a maximum of 40 ng for a single color at a portion which is not an edge portion (80 ng for two colors). An attempt was made to record with the processed record data, and good results were obtained.

FIG. 20 is a functional block diagram of the recording apparatus according to this embodiment.

First, data is input to the recording device. This data is print data and control data for controlling the printing apparatus, and also includes mode data for determining the print mode. The recording mode discrimination means 300 discriminates the first recording mode or the second recording mode from the inputted data based on the recording data and the mode data, and sets the mode accordingly.

In the present embodiment, this determination can be selected from the following two types (manual selection and automatic selection). It is determined by the mode data determined by the user setting.
Specifically, the user selects on the panel of the recording device. Alternatively, it is set by the user with a printer driver processed in the host computer. This can be set for each page to be recorded. Determined automatically. Specifically, there are the following types.

1. Input record data is 360dp
When the resolution is i or less, all are recorded in the first recording mode, and when there is high-resolution data of 720 dpi, recording is performed in the second recording mode. This mode is suitable for recording with a resolution that is faithful to the input data. This is suitable when the input image itself is important.

2. Only when the recorded data is character data,
Recording is performed in the first recording mode. This mode is suitable for recording characters at high speed and for recording a portion other than the characters with high image quality. Characters are suitable for reading and images are suitable for viewing.

3. Only when the recorded data is character data,
Recording is performed in the second recording mode. This mode is suitable when it is desired to record a portion other than a character at high speed and record a portion of the character with high image quality. It is suitable for obtaining a printed matter in which the quality of characters is emphasized and another image is added to it.

4. Recording is performed in the first recording mode only when the recording data is black character data. This mode is suitable for recording only black characters at high speed and recording the other portions with high image quality. The black letters are for reading,
Also, characters and images of other colors are suitable for recording for viewing purposes.

5. Recording is performed in the second recording mode only when the recording data is black character data. This mode is suitable for recording only black characters with high image quality and recording the other portions at high speed. This is suitable for obtaining a printed matter in which the quality of black characters is emphasized and another image is added to it.

6. Only when the recorded data is black data,
Recording is performed in the first recording mode. This mode is suitable for recording only black at high speed and recording the other portions with high image quality.

This case is further divided into two cases. One is the entire recording area including Y, M, and C (C, M,
(Bk adjacent to Y is also included in the area) is recorded with high image quality, and the other is when only Y, M, C data is recorded with high image quality. All of them are suitable for recording with emphasis on color recording images.

7. Only when the recorded data is black data,
Recording is performed in the second recording mode. This mode is suitable for recording only black with high image quality and recording the other portions at high speed.

This case is further divided into two cases. One is for recording only the entire recording area including Bk (including Y, M, C adjacent to Bk) with high image quality, and the other is for recording only Bk data with high image quality. is there. All of them are suitable for recording with emphasis on black recorded images.

8. Recording is performed in the second recording mode only when the recording data is bitmap data. This mode is suitable when it is desired to record only the bitmap data with high image quality and to record the other portions at high speed.

9. Recording is performed in the second recording mode only when the recording medium is plain paper. This mode is suitable for recording in the optimum recording mode according to the recording medium.
For example, on a transparent (OHP) sheet, recording is performed in the first mode (low resolution). When a character or an image recorded on a transparent (OHP) sheet is projected by an overhead projector, the resolution is not reflected even if it is recorded at a high resolution. Therefore, low resolution recording may be performed, and high speed recording may be performed. In a specific implementation in this case, a recording medium determination sensor such as an optical sensor may be provided in the recording device to perform automatic determination. The mode is automatically set by each of these or by combining them.

The high-speed recording mode, which is the first recording mode, and the high-quality recording mode, which is the second recording mode, have the characteristics that they are contradictory to each other in terms of recording quality and recording speed. It is desirable to select according to the purpose.

The mode setting range can be set for each page to be recorded. In addition, it is possible to change automatically within the page depending on the recording area. In this case, when the first and second print modes coexist within the page and within the same scan of the print head, the scan of the print head is the high resolution print second.
The second recording mode includes the first recording mode.

In the first recording mode, the first droplet ejection setting means 301 sets the volume of the ejected ink droplet to be 40 ng. Specifically, the heating element 30 described above
Set to use both (H1, H2). Next, the first recording condition setting unit 302 performs the first recording setting process such as the paper feed amount and the recording data supplied to the heating element 30 of the recording head.

On the other hand, in the second recording mode, the volume of the ink droplet discharged by the second droplet discharge setting means 304 is 20.
Set to ng. Specifically, one of the heating elements 30 (H1, H2) described above is set to be used. Next, the high resolution processing means 305 performs a high resolution processing. The details of this process will be described below. continue,
The data portion processing unit 306 performs smoothing processing and thinning processing which will be described in detail later. Then, the second
The recording condition setting unit 307 performs the second recording condition setting process such as the paper feed amount and the recording data supplied to the heating element 30 of the recording head.

Finally, the print data is sent to the printing apparatus control system 303 including the print head and the like, and the print head, the carriage section, the line feed section and the like are set by the first or second print condition setting means. According to the above, control is performed according to the recording data and the recording mode.

Needless to say, the high resolution recording mode is necessary to obtain high resolution and high quality recording, but the low resolution recording mode is also important. This is because the low-resolution recording mode has a higher recording speed, that is, the time required for data processing and the number of scans of the recording head is shorter.

Thus, the fact that the recording mode can be freely changed or set is extremely effective as a recording method.

FIG. 8 shows the high resolution processing means 305 of FIG.
9 is a flowchart showing the processing of the data partial processing unit 306. In detail, when the input data is the low resolution data having the first resolution, the input data is converted into the high resolution data having the second resolution, and the smoothing and thinning processing is performed. In addition, FIG.
16 is a diagram showing an example of data conversion. The data conversion process will be described with reference to these figures.

In this embodiment, the low resolution which is the first resolution means a resolution of 360 dpi or less, and the high resolution which is the second resolution means a resolution of 720 dpi.

First, in STEP 1, data is input. The data is data at a low resolution of 360 dpi.

FIG. 12 shows input low resolution original image data. Black circles (●) are dot arrangements for recording the character A. Note that this figure is not an actual font, but is shown schematically for the sake of explanation. The original image data is 36
This is data for recording one dot per pixel with a resolution of 0 dpi. Here, the vertical and horizontal squares indicate a resolution of 360 dpi, that is, the minimum recording pixel in a unit of 70.6 μm. The same applies to the following figures.

In STEP 2, the edge portion (edge area) of the input low resolution data is detected. FIG.
The data which detected the edge part of an original image is shown. Black circle (●)
Indicates an edge portion, and a white circle (◯) indicates a non-edge portion. The edge portion detection processing determines whether or not there is print data around the low-resolution input data of interest. If there is no print data in the surroundings, it is the edge portion, and if there is no print data, it is not the edge portion. If it is an edge part, go to STEP 5,
If it is not an edge portion, the process proceeds to STEP3.

STEP 3 is a resolution increasing process. FIG. 14 shows data obtained by converting the original image into 720 dpi. Simply, the data of one pixel of 360 dpi is 720 dpi
It is replaced with four i. STEP 4 is a thinning process (conversion) of the data, and converts the input data in the region other than the edge portion so that the maximum number of ink droplets of the color to be recorded in the 360 dpi square region is 2 dots. The simplest method is to decimate diagonally two dots of data. Since the portion other than the edge portion is originally 1-dot data, there is no inconvenience that the data to be recorded is completely lost by this processing. The data for thinning (0 for thinned dots and 1 for other dots) obtained by this processing is set as data A. Next, it progresses to STEP7.

STEP 5 is a high resolution processing, and the processing content is the same as STEP 3. STEP 6 is a smoothing process. FIG. 15 is a diagram showing a process of performing a smoothing process on the data of FIG. As the smoothing process, here, an algorithm of “cutting the upper protrusion and adding a lower depression” is adopted. The cut data is shown by horizontal lines, and the added data is shown by vertical lines. The data obtained here is referred to as data B.

At STEP 7, the data at the edge portion and the data not at the edge portion are combined. Specifically, the data A for thinning obtained from the data that is not the edge portion
And the smoothing data B, which was the edge portion, are ANDed to obtain recording data.

As described above, the ink recording amount per unit area with 360 dpi corner as the unit area is: 1. The edge portion of the original image and the data portion added by the smoothing process have a maximum of 4 dots per color, and 2 If the color is allowed, it is set to 8 dots, that is, a maximum of 160 ng 2, and if the original image is not an edge portion, it is set to a maximum of 2 dots, and if the color is allowed, it is set to a maximum of 4 dots, that is, 80 ng 2.

Here, the maximum of 4 dots and the maximum of 2 dots per color are set because there may be cases where the number is smaller than that. In the former case, the number may be small due to the edge processing and the smoothing processing. In the latter case, when the data of the original image is multi-valued data, the amount of ink may be small due to the process of uniformly recording the ink to be recorded on the recording medium.

By the above processing, the edge portion was smoothed and recorded while being emphasized more than at the time of 360 dpi recording. In addition, in the portions other than the edge portion, the recording ink amount per unit area was recorded with the same amount as in the 360 dpi recording. Since the portion other than the edge portion does not originally have the meaning of the smoothing process, there is no side effect that deteriorates the recording quality of the processed data.

Here, a 720 dpi high resolution recording dot arrangement using a recording head with a 360 dpi pitch was performed as follows.

FIG. 9 is an explanatory diagram for realizing a high resolution recording dot arrangement. In the figure, the number of discharge ports is 7 for the sake of explanation.
I made it into an individual. The number indicates the number of main scans, and the horizontal line indicates a recordable line. The sub-scanning amount is 3.5 in the low resolution pitch unit, that is, 7 in the high resolution pitch unit, which is the same as the number of nozzles. For example, an effective image recording area of 22 lines is obtained with high resolution by four main scans. In this embodiment, since 32 discharge ports of each color are actually provided, 31 of them are used.
Using 31 nozzles, sub-scanning with 31 pitches, which is the same as the number of nozzles, was performed in high resolution pitch units.

In the above embodiment, since the edge portion is detected based on the low resolution data, the high resolution processing is performed.
Although it was performed at two locations of TEPs 3 and 5, if an algorithm for detecting an edge portion based on high resolution data is adopted, the resolution increasing processing may be performed before the edge portion detecting processing (STEP 2).

Further, in the above example, the edge portion (area) is one layer corresponding to one dot of the original image. This may be not only one layer but also two layers or three layers, and may be set based on the ink used, the recording medium, the recording resolution, and the ink volume to be recorded. Under conditions where the ink absorbability is good, good results may be obtained with about 10 layers.

FIG. 10 shows an example in which four layers of edges are processed as an edge portion. This figure shows a case where the entire inside of a square of 16 × 16 dots is recorded with low resolution.

As described above, the first to tenth layers may be recognized as edge portions and processed. In order to recognize and process the four layers as the edge portion, the above edge processing is easily repeated four times. A portion determined not to be an edge in the first edge processing is extracted, and the extracted portion is further edge-processed. If this is repeated two more times, it means that the edge processing has been performed four times in total, and the logical sum data of the portion determined to be the edge portion in the processing so far is the edge portion of four layers.

Although the present embodiment has been described on the assumption that the recording medium is plain paper, the present invention is effective even if it is a special paper such as a coated paper having an ink receiving layer. Is. If the recording medium has little ink bleeding, the present invention can be used to perform recording at 1440 dpi, which is twice the vertical and horizontal resolution.

Further, even if a print head with a smaller ink discharge volume can be produced inexpensively and stably by, for example, a new proposal or the development of a print head production technique, the present invention can further improve the print quality. It is possible to record at a resolution, for example, 1440 dpi. Alternatively, it is possible to record at 1200 dpi by changing the recording pitch to some extent.

(Second Embodiment) Another Method of Edge Processing Method In the second embodiment, the resolution of only the edge portion of the original image is satisfactorily performed by simple processing. The following processing was performed on the original image shown in FIG.

FIG. 17 shows that the original image is subjected to edge detection processing while the dots are made small for high resolution recording. ● indicates an edge part, and ○ indicates a non-edge part.

FIG. 18 shows a case where dots are added to the original image data at the diagonal grid points l1 of the edge data of the original image. This is designated as Process C.

FIG. 19 shows a case where a dot is added to the data of the original image at an intermediate grid point l2 of two adjacent dots including the grid point l1 of the diagonal line of the data of the edge part of the original image. This is designated as Process D.

In the process C, a maximum of 2 dots is recorded in the edge portion and a maximum of 1 dot is recorded in the non-edge portion with respect to the unit area of 360 dpi square. In the process D, a maximum of 4 dots is recorded in the edge portion and a maximum of 1 dot is recorded in the non-edge portion with respect to the unit area of 360 dpi square.

The process C is suitable when the absorption of the ink on the recording medium is relatively poor, and the process D is particularly suitable when the edge portion is emphasized.

Further, the advantage of the process C is that the recording speed can be made higher than that of the process D and the first embodiment. This is because this method only records dots added at positions (lattice points l1) in which the vertical and horizontal directions are shifted by a half pitch with respect to the recording grid points of the original image of low resolution. It can be recorded by scanning. In the process D in which the print dot positions (lattice points l1 and l2) are twice as high as the low resolution in both the vertical and horizontal directions and in the first embodiment, a scan equivalent to four times is required. As described above, the method of recording the additional dots only on the diagonal grid points 11 of the data of the edge portion of the original image has an advantage that not only the recording quality is improved but also high resolution and relatively high speed recording can be realized. is there.

(Embodiment 3) High resolution data is recorded only at the edge portion with high resolution In the first embodiment, a method of obtaining and recording high resolution data from low resolution data has been described. On the other hand, when high-resolution data is input to the recording device in advance, the first embodiment
It is not necessary to add dots (smoothing processing) in STEP 6 shown in FIG. In the present embodiment, by appropriately thinning out the print data of the portion other than the edge portion, the high resolution recording portion of the edge portion has the high resolution as it is, and the portion other than the edge portion is recorded on the recording medium without substantially lowering the resolution. It is possible to reduce the recording density of ink drops.

FIG. 21 is a flow chart showing the process of thinning out the input data when the input data is the high resolution data having the second resolution.

First, in STEP 11, data is input. The data is data at 720 dpi which is a high resolution.

At STEP 12, the edge portion (edge area) of the input low resolution data is detected. STEP
A data thinning process (conversion) 13 converts input data in a region that is not an edge portion so as to appropriately thin print data. As a simple method, the print data is converted so that the maximum size of the ink droplet of the color to be printed is 2 dots in the area of 1/2 resolution, here 360 dpi square. The simplest method is to decimate diagonally two dots of data. The data for thinning (0 for thinned dots and 1 for other dots) obtained by this processing is set as data A.

At STEP 14, the data at the edge portion and the data not at the edge portion are combined. Specifically, the data A for thinning obtained from the data that is not the edge portion
And the data at the edge portion, that is, the input data, are logically ANDed to obtain recording data.

After that, recording is performed as in the first embodiment.

(Fourth Embodiment) Different Color Adjacent Areas are Recorded at Low Resolution In the first embodiment, the case of recording with a single color has been mainly described, but at the time of color recording, recording is performed with two or more colors of ink. When two or more inks of different colors are printed adjacent to each other, the adjacent portions of different colors have an edge portion with a single color, but do not have an edge portion as a recording area.

In this embodiment, adjacent portions of different colors are recorded by the same process as the recording at low resolution.

FIG. 11 shows an example in which Bk and Y are adjacent to each other. A black circle () indicates Bk and a white circle (◯) indicates Y. The original image is fill data of 16 × 12 dots for each color. A region adjacent to Bk and Y where the logical sum data of Bk data and Y data is not an edge portion is processed as not being an edge portion for each color, and the recording density of ink droplets is reduced.

FIG. 22 is a flow chart for converting the input data into the high resolution data having the second resolution and performing the smoothing and thinning processing when the input data is the low resolution data having the first resolution. In the figure, STEP
21 to 27 are the same as STEP 11 to 17 of FIG.

In STEP 21, low resolution data is input,
If it is determined to be an edge portion in STEP 22, STE
In P28, it is determined whether or not the boundary portion is a different color. Here, 4
The case where more than one layer is adjacent is determined to be the boundary. For example, since it is determined that the area A1 is not the different color boundary portion, the process proceeds to STEP25 as in FIG. 8. However, since the region A2 is determined to be the different color boundary portion, the process proceeds to STEP23 and thinning processing is performed.

(Fifth Embodiment) Another Method of Thinning Out FIG. 23 showing the fifth embodiment shows another example of the thinning out method in the non-edge portion shown in FIG. In this embodiment, the non-edge portion does not use high resolution data but low resolution data. Since the dot for high resolution recording is 20 ng and the dot for low resolution is 40 ng, the same thinning effect can be obtained by using 1 dot of low resolution data instead of 2 dots of high resolution data. .

(Embodiment 6) When using another type of recording head FIG. 7 shows an example of a serial type ink jet color printer to which the present invention is applied.

The print head 1 has a plurality of nozzle rows and is a device for recording an image by forming dots on a recording medium by ejecting ink droplets. In this embodiment, a piezoelectric element, which is an electromechanical converter, is used to positively generate different ink droplet diameters (that is, different ink ejection amounts). By controlling the voltage value applied to the piezo element, it is possible to eject different amounts of ink from the same nozzle. Also, different color inks are ejected from different print heads, and a color image is formed on the recording medium by the color mixture of these ink droplets. Print head row 1K (black), 1C (cyan), 1M
(Magenta) and 1Y (yellow) are mounted on the carriage 201, and images are formed on the recording medium in this order during one scan in one direction.

FIG. 6 is a diagram showing the configuration of the print head array for each color and the ink tank. For example, when forming a red (hereinafter R) image, first, a magenta (hereinafter M) ink droplet is landed on the recording medium, and then yellow (hereinafter Y) is landed on the M recording dot to mix the colors. It will appear as a red dot. Similarly, when a green (hereinafter G) image is formed, ink droplets are landed in the order of C and Y, and when a blue (hereinafter B) image is formed, ink droplets are landed in the order of C and M to form a color image. Form.

Power from the carriage drive motor 8 is transmitted to the carriage 201 by the belts 6 and 7 to move on the sliding shaft. Printing in the digit direction is performed during the operation in the main scanning direction. The recovery unit 400 has a function of always keeping the print head in a good state, and in the non-printing state, the cap row 420 blocks the ejection surface of the print head to prevent drying and the like. For this reason, the carriage 201 becomes the recovery unit 400.
The position opposite to is referred to as a home position (hereinafter referred to as HP). In the normal printing operation, the carriage moves from this HP to perform printing, so in this example, printing is performed from left to right in FIG. For feeding in the sub-scanning direction, a recording medium is fed by a paper feed motor (not shown). The direction A in the figure is the paper feed direction. A flexible cable 9 supplies an electric signal to the recording head. The ink is supplied by the ink cassettes 10K, 10C mounted on the carriage 201.
It is performed from 10M and 10Y. The ink supply is not limited to the configuration shown in the figure, but a configuration is also provided in which each row of ink is supplied from the ink tank provided in the recording apparatus main body to the print head on the carriage by providing a tube row for ink supply like the flexible cable. May be

FIG. 5 shows details of the recording head shown in FIG. As the structure of the recording head, for example, a recording head having a structure using an electromechanical transducer as shown in JP-A-63-237669 is used. It is possible to obtain two different ink volumes by using the piezoelectric element 38, which is an electromechanical variant, and changing the driving conditions for driving the piezoelectric element. The driving condition is to control the voltage value which is the driving energy and the driving time, and may be the control of the driving waveform.

(Summary) The features of the above-described embodiments are summarized as follows. Depending on the recording mode, high-resolution recording and low-resolution recording are used separately according to the purpose of use. Recording mode can be set manually or automatically,
It is possible to switch on a page-by-page basis or within a page.

1. Lower resolution data is recorded with higher resolution.

Means for detecting the edge portion of the recorded data, means for converting low resolution data into high resolution which is twice the vertical and horizontal directions,
It has a unit for ejecting about 1/2 unit ink droplets at the time of low resolution recording and a smoothing processing unit. The edge portion of the input low resolution data is smoothed, and each color is the unit of the minimum recording pixel of low resolution. A maximum of 4 ink droplets are recorded on the area at the high resolution recording position, and the non-edge portion of the low resolution data has a maximum unit area of 2 for each color.
Record with one ink drop.

2. The high resolution data is only the edge part,
Areas that are not edges are recorded with a reduced resolution. When the input data is high-resolution data, the edge portion is recorded as it is, and the portion other than the edge portion is subjected to the low-resolution processing to reduce the number of recording dots (the number of ink hits on the recording medium) for recording. Ink overflow can be prevented and recording can be speeded up.

3. In the case of 1 or 2 above, when two or more different color inks are printed, adjacent portions of different colors are printed by the same process as the low resolution printing.

4. When the input data is high resolution data, data other than the edge portion is appropriately thinned out.

5. The edge portion is a region of 1 to 10 pixels from the outermost contour of the recording data depending on the recording conditions.

6. Determine whether the input data is low resolution data or high resolution data, and set whether the recording resolution is the low resolution recording mode or the high resolution recording mode, and the recording resolution is the low resolution. In the recording mode, if the input data is low resolution data, it is recorded as it is.

The recording resolution is the low resolution recording mode,
When the input data is high resolution data, the input data is appropriately thinned out and recorded.

The recording resolution is the high resolution recording mode,
If the input data is low-resolution data, the input data is subjected to high-resolution processing and recorded.

The recording resolution is the high resolution recording mode,
When the input data is high resolution data, the input data is appropriately thinned out and recorded.

As described above, according to each of the embodiments, a slightly small volume of ink droplets is ejected so that the recorded ink does not overflow on the recording medium and the conventional low resolution input data is doubled. It is possible to record at the resolution.

Furthermore, high resolution recording on plain paper becomes possible. Further, the fact that high-resolution recording is possible also means that high-gradation recording is possible.

Further, even when the input data is high resolution data, it is possible to record the data at the high resolution as it is by thinning out the data other than the edge portion appropriately.

(Others) The present invention is particularly effective in a recording apparatus using an inkjet recording head for recording by forming flying droplets by utilizing thermal energy among the inkjet recording methods. Is.

Regarding its typical structure and principle, 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 is a so-called on-demand type,
It can be applied to any of the continuous type, but especially in the case of the on-demand type, it can be applied to the sheet holding the liquid (ink) or the electrothermal converter arranged corresponding to the liquid path. By applying at least one drive signal that corresponds to the recorded information and gives a rapid temperature rise exceeding nucleate boiling, heat energy is generated in the electrothermal converter, and film boiling occurs on the heat acting surface of the recording head. Liquid (ink) that is generated and eventually responds to this drive signal as a single unit
It is effective because bubbles can be formed inside. The liquid (ink) is ejected through the ejection openings by the growth and contraction of the bubbles to form at least one droplet. It is more preferable to make this drive signal into a pulse shape because bubbles can be immediately and appropriately grown and contracted, so that liquid (ink) ejection with excellent responsiveness can be achieved. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. 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 ejection port, the liquid passage, and the electrothermal converter (the straight liquid passage or the right-angled liquid passage) as disclosed in the above-mentioned specifications. U.S. Pat. No. 4,558,333 and U.S. Pat. No. 44, which disclose a configuration in which a heat acting portion is arranged in a bending region.
The structure using the specification of No. 59600 is also included in the present invention. In addition, Japanese Unexamined Patent Publication No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of the electrothermal converter for a plurality of electrothermal converters, and an opening for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the configuration corresponding to the ejection portion is disclosed in JP-A-59-138461. That is, according to the present invention, recording can be surely and efficiently performed regardless of the form of the recording head.

In addition, even in the case of the serial type as in the above example, the recording head fixed to the main body of the apparatus or the electrical connection to the main body of the apparatus or the ink from the main body of the apparatus by being attached to the main body of the apparatus. The present invention is also effective when a replaceable chip-type recording head that can be supplied or a cartridge-type recording head in which an ink tank is integrally provided in the recording head itself is used.

Further, as the constitution of the recording apparatus of the present invention, it is preferable to add the ejection recovery means of the recording head, the preliminary auxiliary means and the like because the effects of the present invention can be further stabilized. Specifically, heating is performed by using a capping unit, a cleaning unit, a pressure or suction unit for the recording head, an electrothermal converter or a heating element other than this, or a combination thereof. Examples thereof include a preliminary heating unit for performing the discharge and a preliminary discharge unit for performing discharge different from the recording.

Regarding the type and number of recording heads to be mounted, two or more recording heads may be provided corresponding to a plurality of inks having different recording colors and densities. That is, for example, the recording mode of the recording apparatus is not limited to the recording mode of only the mainstream color such as black, but it may be either the recording head is integrally formed or a plurality of combinations may be used. The present invention is also extremely effective for an apparatus provided with at least one of full-color recording modes by color mixing.

In addition, in the above-described embodiments of the present invention, the ink is described as a liquid, but an ink that solidifies at room temperature or lower and that softens or liquefies at room temperature may be used. Or, in the inkjet system, it is common to adjust the temperature of the ink itself within the range of 30 ° C. or higher and 70 ° C. or lower to control the temperature so that the viscosity of the ink is within the stable ejection range. Sometimes, a liquid ink may be used. In addition, the temperature rise due to thermal energy is positively prevented by using it as the energy of the state change from the solid state of the ink to the liquid state, or in order to prevent the evaporation of the ink, it is solidified and heated in the standing state. You may use the ink liquefied by. 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
JP-A-54-56847 or JP-A-60-7
As described in Japanese Patent No. 1260, it may be configured to face the electrothermal converter in a state of being held as a liquid or a solid in the concave portion or the through hole of the porous sheet. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition, as the form of the ink jet recording apparatus of the present invention, other than the one used as an image output terminal of information processing equipment such as a computer, a copying apparatus combined with a reader or the like, and a facsimile apparatus having a transmitting / receiving function are provided. It may be a form or the like.

[0121]

According to the present invention, the input data is converted into the print data for driving the print head according to the print mode,
Since printing can be performed according to the printing mode set based on the converted printing data, high-quality printing with high resolution can be performed regardless of the input data.

[Brief description of drawings]

FIG. 1 is a perspective view of a recording apparatus applicable to the present invention.

FIG. 2 is a perspective view of a recording head unit.

FIG. 3 is an enlarged cross-sectional view of a recording head.

FIG. 4 is an enlarged cross-sectional view of a recording head.

FIG. 5 is a diagram showing details of another recording head applicable to the present invention.

FIG. 6 is a diagram showing another recording head applicable to the present invention.

FIG. 7 is a perspective view of another recording apparatus applicable to the present invention.

FIG. 8 is a flowchart for converting input data into recording data.

FIG. 9 is an explanatory diagram for realizing a high resolution recording dot arrangement.

FIG. 10 is a diagram showing an example in which edges of four layers are processed as edge portions.

FIG. 11 is a diagram illustrating a recording example of a boundary portion of different colors.

FIG. 12 is a diagram showing an original image of input data.

FIG. 13 is a diagram showing an edge portion of an original image.

FIG. 14 is a diagram showing data converted into high resolution.

FIG. 15 is a diagram showing data subjected to smoothing processing.

16 is a diagram showing recording data of Example 1. FIG.

FIG. 17 is a diagram illustrating data obtained by edge detection of the original image according to the second embodiment.

FIG. 18 is a diagram illustrating a process of a second embodiment.

FIG. 19 is a diagram showing another process of the second embodiment.

FIG. 20 is a diagram showing functional blocks of the first embodiment.

FIG. 21 is a diagram showing a flowchart of Example 3;

FIG. 22 is a diagram showing a flowchart of the fourth embodiment.

FIG. 23 is a diagram showing recording data of Example 5;

[Explanation of symbols]

 20 Color Ink Tank 21 Black Ink Tank 22 Ejection Surface 23 Ejection Port 30 Heating Element 31 Recording Medium 35 Ink Drop 38 Piezoelectric Element 100 Recording Device 101 Carriage 102 Recording Head 103 Recording Head Unit 300 Mode Discriminating Means 301 First Droplet Ejection Setting means 302 First recording condition setting means 303 Recording device control system 304 Second droplet discharge setting means 305 High resolution processing means 306 Data partial processing 307 Second recording condition setting means

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location G06T 1/00 11/00 H04N 1/52 9365-5H G06F 15/62 310 A 9365-5H 15 / 72 H04N 1/46 B (72) Inventor Masao Kato 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (15)

[Claims] 1. An inkjet recording method for performing recording using a recording head for ejecting ink, comprising: a first recording mode for performing recording by ejecting a relatively large amount of ink at low resolution; A second recording mode in which a small amount of ink is ejected to perform recording is set, and depending on the set first or second recording mode,
Inkjet recording comprising a step of converting input data into recording data for driving the recording head, and performing recording control according to a recording mode set by the setting means based on the converted recording data. Method. 2. In the converting step, when the second recording mode is set and the input data is low resolution data, the input data is converted into high resolution data and a continuous area of the converted high resolution data is thinned out. The ink jet recording method according to claim 1, wherein the data is converted into the data. 3. An ink jet recording apparatus for performing recording by using a recording head for ejecting ink, and a first recording mode for performing recording by ejecting a relatively large amount of ink at low resolution, and a recording mode at high resolution. Setting means for setting a second recording mode in which a small amount of ink is ejected for recording, and input data is recorded according to the first or second recording mode set by the setting means. And a recording control unit that performs recording control according to the recording mode set by the setting unit based on the recording data converted by the converting unit. Characteristic inkjet recording device. 4. The ink jet recording apparatus according to claim 3, wherein the conversion unit converts the input data into high resolution data when the second recording mode is set and the input data is low resolution data. . 5. The conversion means adds data to an edge portion of low-resolution input data, and a portion other than the edge portion is
The ink jet recording apparatus according to claim 4, wherein the high resolution data is converted as it is or by adding the input data so as to be recorded twice. 6. The conversion means is arranged so that the data of the edge portion of the low-resolution input data are adjacent to each other in both vertical and horizontal directions and in an oblique direction.
6. The ink jet recording apparatus according to claim 5, wherein the data is added to an edge portion of the input data by adding the data to an intermediate position only in the diagonal direction. 7. The ink jet recording apparatus according to claim 4, wherein the conversion unit converts the data of a portion which is not an edge portion into thinned data. 8. The inkjet recording apparatus according to claim 5, wherein the edge portion is a peripheral area of the recording area. 9. The ink jet recording apparatus according to claim 8, wherein the edge portion is a peripheral area of logical sum data of plural color data in the case of plural colors. 10. The ink jet recording apparatus according to claim 3, wherein when the first mode is set and the input data is high resolution data, the converting means converts the input data into thinned data. 11. The ink jet recording apparatus according to claim 10, wherein the conversion unit converts the data of a portion that is not an edge portion into thinned data. 12. The inkjet recording apparatus according to claim 11, wherein the edge portion is a peripheral area of the recording area. 13. The ink jet recording apparatus according to claim 12, wherein the edge portion is a peripheral area of logical sum data of plural color data in the case of plural colors. 14. The ink jet recording apparatus according to claim 1, wherein the recording head ejects ink by using thermal energy. 15. The inkjet recording apparatus according to claim 1, wherein the recording head ejects ink by using mechanical energy.