JP3244943B2 - Ink jet recording method and recording apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording method and apparatus for forming characters and images by depositing ink droplets on a recording medium, and more particularly to an ink jet recording suitable for high resolution recording or high gradation recording. It relates to a method and a recording method.

The present invention relates to ordinary paper, special paper, cloth, OHP
The present invention can be applied to all devices using a recording medium such as paper.
Specific examples of applicable devices include a printer, a copying machine, a facsimile, and the like.

[0003]

2. Description of the Related Art Ink jet recording has low noise, low running cost, easy downsizing of the apparatus, easy colorization,
There are advantages such as. Color ink jet recording uses three color inks of cyan (C), magenta (M), and yellow (Y), or black (B)
This is performed using four colors of ink to which k) is added. Some color recordings are performed using inks such as green (G), red (R), and blue (B).

In the 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, a method has been put to practical use that has been given a printing suitability for “plain paper” used in large quantities in printers, copiers, and the like due to improvements in ink.

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

Comparing the case of recording on special paper and the case of recording on plain paper with ink droplets of the same volume designed to reduce ink bleeding, it is obvious that bleeding on plain paper is Be larger than paper. Therefore, high-resolution recording on plain paper is disadvantageous over dedicated paper. Therefore,
Recording on plain paper may be performed with ink droplets of smaller volume.

It is also possible to reduce bleeding by reducing the average amount of ink per unit area on plain paper. However, in this case, there are drawbacks in that the recording characteristics during gray gradation recording are deteriorated, 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, U.S. Pat. No. 4,809,021 describes smooth printing using dots of three or more sizes. This is a technique for smoothly recording characters, for example, using dots of various sizes. In this method, preparations for constantly recording dots of various sizes are required.
For example, a recording head having various types of nozzle diameters and a part for converting an image to be recorded into data corresponding to each nozzle diameter are required.

There are also many proposals on edge enhancement as a method of improving image quality. For example, Japanese Patent Laid-Open No. 1-21
Japanese Patent Application Laid-Open No. 2176 discloses that an image signal is secondarily differentiated, a signal of an original image is calculated as smoothed data, and an edge portion is emphasized. This is a proposal for edge enhancement with constant resolution. There are many other proposals related to 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, a high-resolution and high-quality image cannot be obtained according to various input data.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an ink jet recording method and a recording apparatus capable of performing high resolution and high quality recording irrespective of input data.

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

[0014]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an ink jet recording method for performing recording using a recording head for discharging ink by discharging a relatively large amount of ink at a low resolution. A first printing mode for performing printing and a second printing mode for performing printing by ejecting a relatively small amount of ink at a high resolution are set, and the low-resolution or high-resolution input data is The print data is converted into print data for driving the print head having a resolution corresponding to the first or second print mode, and print control is performed based on the converted print data in accordance with the print mode set by the setting unit. It is characterized by having a process.

According to the present invention, there is provided an ink jet recording apparatus which performs recording using a recording head which discharges ink, a first recording mode in which recording is performed by discharging a relatively large amount of ink at a low resolution, Setting means for setting a second printing mode for performing printing by ejecting a relatively small amount of ink at a high resolution; and inputting low-resolution or high-resolution input data to the first or the second data set by the setting means. Converting means for converting the data into print data for driving the print head having a resolution corresponding to the second print mode; and converting the print data set by the setting means based on the print data converted by the converting means. Recording control means for performing recording control.

[0016]

According to the above arrangement, the low-resolution or high-resolution input data is converted into print data for driving a print head having a resolution corresponding to the print mode, and the print mode is set based on the converted print data. Since the recording can be performed in accordance with the input data, high-quality recording can be performed regardless of the resolution 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 sheet feeding position of the recording apparatus 100 is conveyed by the feed roller 109 to a recordable area of the recording head unit 103. A metal platen 108 is provided below the recording medium in the recordable area. Carriage 101
Is configured to be movable in a direction determined by the two guide shafts 104 and 105, and reciprocally scans a recording area. On the carriage 101, a print head unit 103 including an ink tank for supplying four color inks and a print head for discharging those inks is mounted.
The four color inks provided in the ink jet 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 for displaying various recording mode settings and the status 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 the color inks 1 and the other three colors are integrally stored, are connected to the recording head 102 by pipes, respectively, and the ink in each tank is supplied to the recording head 102. Bk,
There is an ejection port array 23 composed of a plurality of ejection ports corresponding to each color of C, M, and Y. The number of ejection ports for each color is 32. The intervals between the 32 orifices of each color are linearly arranged at a density of 360 dpi at which the dot pitch is about 70 μm. In addition, the ejection port arrays of the respective colors are arranged at intervals of 8 dot pitch. The ejection openings for the respective colors are arranged so as to be recorded in the order of Bk, C, M, and Y.

In the ink jet recording apparatus according to the present embodiment, an electric / heat converter is arranged corresponding to a liquid path (nozzle) of ink, and a drive signal corresponding to recording information is applied to the electric / heat converter to make a nozzle. That is, a so-called bubble jet recording method in which ink is ejected from the printer is adopted.

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

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

At the time of recording at a normal low resolution, 360 dpi
Record at a recording density of At the time of ink ejection at this time, H1 and H2 corresponding to each ejection port generate heat simultaneously. The ink in the nozzle, which is rapidly heated by the heat generated by the heating elements H1 and H2, forms bubbles due to film boiling, and the pressure of the bubble generation causes the ink droplets 35 to form the recording medium 3 as shown in FIG.
1 to form characters and images on the recording medium. In this case, the volume of each color ink droplet to be ejected is about 40 ng.

On the other hand, during high-resolution printing, only the nozzle H1 is controlled to generate heat, and the volume of each color ink droplet ejected is about 20 times smaller than during low-resolution printing.
ng.

As described above, high-resolution printing was performed using only a small volume of ink using a print head capable of discharging different volumes from the same nozzle. In order to obtain ejection of different ink volumes, besides the method of using two electrothermal transducers for each nozzle as described above, for example, controlling the power applied to the electrothermal transducer during ink ejection, It is also possible by controlling the temperature of the above, and in the present invention, any method can be applied.

Each of the discharge ports 23 is provided with an ink liquid path communicating with the discharge port, and a common liquid for supplying ink to these liquid paths is provided behind the portion where the ink liquid path is provided. A chamber 32 is provided. Heating elements 30 (H1, H2 shown in FIG. 4), which are electrothermal converters that generate thermal energy used for discharging ink droplets from these discharge ports, are provided in ink liquid paths corresponding to each of the discharge ports. And an electrode wiring for supplying power thereto. These heating elements 30 and electrode wirings are formed on a 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 does not directly contact the heating element. Further, the discharge port, the ink liquid path, the common liquid chamber, and the like are formed by laminating the partition wall 34 made of a resin or a glass material on the substrate.

As described above, a recording head using an electrothermal transducer uses a bubble formed by applying thermal energy when ejecting ink droplets, and is therefore generally called a bubble jet recording head.

In this embodiment, the volume of the ink droplets of each color to be ejected is set to about 40 ng at the time of recording at 360 dpi, which is the normal low resolution recording, and the volume of the ink droplets of each color ejected at the time of the high resolution recording is set. The volume was about 20 ng.
The reason will be described below.

This is because the average maximum ink absorption amount per pixel at 360 dpi on plain paper is about 80 ng.
It is determined from that. When recording the secondary colors red (R), green (G), and blue (B),
The Y, M, and C ink droplets are mixed by two dots. For this reason,
The volume of each color ink droplet 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 at 720 dpi,
Originally, the volume of one dot of ink should be 10 ng, which is 1/4 that of 360 dpi recording, and four dots should be recorded in the area where one dot was recorded at 360 dpi recording. However, it is quite difficult to mass-produce a multi-nozzle print head having a plurality of nozzles at a desired print position at a desired timing at a desired timing stably at a desired timing, which is about 10 ng of an ink droplet. Is difficult. This is due to a decrease in productivity due to processing accuracy of the nozzle, clogging of fine dust, and the like. Furthermore, it is technically difficult to achieve about 40 ng of ink droplet ejection during normal printing and about 10 ng of ink droplet ejection for high-density printing. Setting the volume to 20 ng is actually possible compared to setting the volume of the ejected ink droplet to 10 ng, and by applying the present invention, high-resolution recording with excellent image quality can be performed.

Further, with the progress of production technology in the future, 10
When a recording head capable of stably ejecting ink droplets having a smaller volume of ng or even 5 ng can be produced, by applying the present invention, higher-resolution recording can be performed. Become.

The determination of the average maximum ink absorption amount per unit area in a recording medium is usually designed as a worst value when a region where a specific area is uniformly painted is recorded. This is because the ink in the uniformly wetted portion can penetrate only inside the recording medium.
On the other hand, near the edge portion, the ink can overflow and permeate out of the recording area, but is not limited to this.

On the other hand, when recording characters and images, it is generally known that the higher the edge portion, the better the quality.

Therefore, the ink recording amount per unit area with a 360 dpi angle as the unit area is set to a maximum of 80 ng for a single color (160 ng for two colors) at an edge portion and a maximum of 40 ng for a non-edge portion (80 ng for two colors). Attempts were made to print with the processed print 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 includes mode data for determining the print mode. The recording mode discriminating means 300 discriminates between the first recording mode and the second recording mode based on the recording data and the mode data among the input data, and sets the mode accordingly.

In this embodiment, the following two types of discrimination (manual selection and automatic selection) can be selected. Determined by mode data determined by user setting.
Specifically, the user makes a selection on the panel of the recording device. Alternatively, the setting is made by the user with a printer driver that processes in the host computer. This can be set for each page to be recorded. Determined by automatic setting. More specifically, there are the following types.

1. The input recording data is 360 dp
When the resolution is i or less, all the data is recorded in the first recording mode, and when there is 720 dpi high-resolution data, the data is recorded in the second recording mode. This mode is suitable for recording at a resolution faithful to the input data. This is suitable when emphasizing the input image itself.

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 a high speed and recording portions 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 for recording a portion other than a character at a high speed and recording a character portion with high image quality. It is suitable for obtaining a recorded matter in which the quality of characters is emphasized and other images are added thereto.

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 a high speed and recording the other portions with high image quality. Black letters are for reading purposes,
Also, characters and images of other colors are suitable for recording for viewing purposes.

5. Only when the recording data is black character data, recording is performed in the second recording mode. This mode is suitable when only black characters are to be recorded with high image quality and other portions are to be recorded at high speed. This method is suitable for obtaining a recorded matter in which the quality of black characters is emphasized and other images are added thereto.

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

This case is further divided into two cases. One is that the entire recording area including Y, M, and C (C, M,
This is the case where only Bk adjacent to Y is included in the area) is recorded with high image quality, and the other is the case where only Y, M and C data are recorded with high image quality. Any of them is suitable for printing in which color printing images are emphasized.

7. Only when the recording 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 other portions at high speed.

This case is further divided into two cases. One is a case where only the entire recording area including Bk (including Y, M, and C adjacent to Bk) is recorded with high image quality, and the other is a case where only Bk data is recorded with high image quality. is there. Any of them is suitable for recording in which a black recording image is emphasized.

8. Recording is performed in the second recording mode only when the recording data is bitmap data. This mode is suitable when only bitmap data is to be recorded with high image quality, and other portions are to be recorded 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 image recorded on a transparent (OHP) sheet is projected by an overhead projector, the resolution is not reflected even when recorded at a high resolution. Therefore, recording may be performed at a low resolution or at a high speed. In a specific implementation in this case, a recording device may be provided with a recording medium discrimination sensor such as an optical sensor to perform automatic discrimination. 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 characteristics that are contradictory in terms of recording quality and recording speed. It is desirable to select according to the purpose.

The range of the mode setting can be set for each page to be recorded. Also, it can be automatically changed depending on the recording area within the page. In this case, when the first and second print modes are mixed in the page and within the same scan of the print head, the scan of the print head is the second scan which is high-resolution printing.
, And 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 is used.
(H1, H2) are set to be used. Next, the first recording condition setting unit 302 performs a first recording setting process such as a paper feed amount and recording data supplied to the heating element 30 of the recording head.

On the other hand, in the second recording mode, the second droplet ejection setting means 304 sets the volume of the ejected ink droplet to 20.
ng. Specifically, one of the above-described heating elements 30 (H1, H2) is set to be used. Next, the high-resolution processing unit 305 performs a high-resolution processing. Details of this processing will be described below. continue,
The data partial processing unit 306 performs a smoothing process and a thinning process, which will be described in detail later. Then, the second
The recording condition setting means 307 performs a second recording condition setting process such as a paper feed amount and 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 unit, the line feed unit and the like are adjusted to the conditions set by the first or second printing condition setting means. In accordance with the recording data and the recording mode.

Here, it goes without saying that the high-resolution recording mode is necessary for obtaining high-resolution, high-quality recording, but the low-resolution recording mode is also important. This is because the printing speed is higher in the low-resolution printing mode, that is, the data processing time and the time depending on the number of scans of the printing head are shorter.

As described above, the point 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.
6 is a flowchart showing processing of a data partial processing unit 306. More specifically, a flowchart is shown in which, when the input data is low-resolution data having the first resolution, the input data is converted into high-resolution data having the second resolution, and smoothing and thinning processing are performed. FIG.
16 are diagrams illustrating an example of data conversion. The data conversion process will be described with reference to these figures.

In this embodiment, the first low resolution refers to a resolution of 360 dpi or less, and the second high resolution refers to a 720 dpi resolution.

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. A black dot (•) is a dot arrangement for recording the character A. This diagram is not an actual font, but is schematically shown for explanation. The original image data is 36
This is data for recording one dot per pixel at a resolution of 0 dpi. Here, the vertical and horizontal boxes indicate the resolution of 360 dpi, that is, the minimum recording pixel in units of 70.6 μm. The same applies to the following figures.

In STEP 2, the edge part (edge area) of the input low-resolution data is detected. FIG.
The data which detected the edge part of the original image is shown. Black circle (●)
Indicates an edge portion, and a white circle (○) indicates a non-edge portion. In the edge portion detection process, a determination process is performed based on whether or not recording data exists around the low-resolution input data of interest. If there is no recording data around, it is an edge, and if there is no recording data, it is not an edge. If it is an edge, go to STEP5.
If it is not an edge, the process proceeds to STEP3.

STEP 3 is a high resolution process. FIG. 14 shows data obtained by converting an original image into 720 dpi. The data of one pixel of 360 dpi is simply converted to 720 dpi.
i. In STEP 4, recording data is converted by thinning data (conversion) so that ink droplets of a color to be recorded in a 360 dpi angle area have a maximum of two dots with respect to input data in an area other than an edge portion. The simplest method is to thin out data of two diagonal dots. Since the portion other than the edge portion is originally one-dot data, there is no inconvenience that data to be recorded is completely lost by this processing. The data for thinning out obtained by this processing (the dot to be thinned out is 0 and the others are 1) is data A. Next, the operation proceeds to STEP7.

STEP 5 is a high-resolution process, and the contents of the process are the same as those in STEP 3. STEP 6 is a smoothing process. FIG. 15 is a diagram showing a process of performing smoothing processing on the data of FIG. Here, the smoothing process employs an algorithm of “cutting an upper protruding portion and adding a lower recess”. The cut data is indicated by a horizontal line, and the added data is indicated by a vertical line. The data obtained here is referred to as data B.

In STEP 7, the data at the edge portion and the data at the non-edge portion are combined. Specifically, data A for thinning obtained from data that was not an edge portion
Is ANDed with the smoothing data B, which is the edge portion, to obtain recording data.

As described above, the ink recording amount per unit area with the 360 dpi angle as the unit area is: 1. The edge portion in the original image and the data portion added by the smoothing process are 4 dots max. Eight dots, that is, 160 ng 2 at maximum when colors are allowed, and a maximum of 2 dots per color for a portion that is not an edge portion in the original image, and four dots at maximum, that is, 80 ng when two colors are allowed.

Here, the maximum of 4 dots and the maximum of 2 dots are set for each color, because there may be a case 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 the ink to be printed may be small due to the process of uniformly printing the ink on the printing medium.

With the above processing, the edge portion was smoothed and recorded with emphasis from 360 dpi recording. In addition, the portion other than the edge portion was recorded at the same recording ink amount per unit area as in 360 dpi recording. Since the part other than the edge part does not originally have the meaning of the smoothing processing, there is no side effect of deteriorating the recording quality of the processed data.

The arrangement of 720 dpi high resolution recording dots using a 360 dpi pitch recording head 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 explanation.
It was made into pieces. The number indicates the number of main scans, and the horizontal line indicates a recordable line. The amount of sub-scanning is 3.5 in a low resolution pitch unit, that is, the same as the number of nozzles in a high resolution pitch unit of 7. For example, an effective image recording area of 22 lines with high resolution is obtained by four main scans. In the present embodiment, 32 outlets for each color are actually provided.
Sub-scanning of 31 pitches was performed using the number of nozzles in units of high resolution pitches, the same as the number of nozzles.

In the above embodiment, since the edge portion is detected based on the low-resolution data, the high-resolution processing is performed in S.
The processing was performed at two locations, TEP3 and TEP5. However, if an algorithm for detecting an edge portion based on high-resolution data is adopted, the high-resolution process may be performed before the edge portion detection process (STEP2).

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 of good ink absorbency, good results may be obtained with about 10 layers.

FIG. 10 shows an example in which edges of four layers are processed as edge portions. The figure shows a case in which the entire inside of a 16 × 16 dot square is recorded at a low resolution.

As described above, the first to tenth layers may be recognized as edge portions and processed. Recognition and processing of the four layers as edge portions can be easily performed by repeating the edge processing four times. A portion determined not to be an edge in the first edge processing is extracted, and the extracted portion is further subjected to edge processing. If this process is repeated two more times, the edge processing has been performed a total of four times, and the data of the logical sum of the parts determined to be the edge part in the processing so far is the edge part of the four layers.

Although the present embodiment has been described on the assumption that the recording medium is plain paper, the present invention can be applied to a special paper such as a coated paper having an ink receiving layer. It is. This means that 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, for example, a new proposal or a development of a print head production technique makes it possible to produce a print head with a smaller ink ejection volume at low cost and in a stable manner, the present invention provides a further improvement. Recording at a resolution of, for example, 1440 dpi becomes possible. Alternatively, recording at 1200 dpi can be performed by slightly changing the recording pitch.

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

FIG. 17 shows the original image obtained by reducing the size of dots for high-resolution recording and performing edge detection processing on the original image. ● indicates an edge portion, and 部分 indicates a non-edge portion.

FIG. 18 shows a case where a dot is added to the diagonal grid point l1 of the data of the edge part of the original image with respect to the data of the original image. This is referred to as process C.

FIG. 19 shows a case where a dot is added to the intermediate grid point l2 of two adjacent dots including the diagonal grid point l1 of the data of the edge portion of the original image with respect to the data of the original image. This is referred to as process D.

In the process C, a maximum of 2 dots are recorded at an edge portion and a maximum of 1 dot is recorded at a non-edge portion with respect to a unit area of 360 dpi angle. Process D records a maximum of 4 dots at the edge portion and a maximum of 1 dot at portions other than the edge portion with respect to a unit area of 360 dpi angle.

The process C is suitable when the ink absorption of the recording medium is relatively poor, and the process D is a method particularly suitable for emphasizing the edge portion.

The advantage of the process C is that the recording speed can be increased as compared with the process D and the first embodiment. This is because, in this method, only dots added at positions (lattice points 11) vertically and horizontally shifted by a half pitch with respect to the recording lattice points of the original image having a low resolution are recorded. You can record by scanning equivalent. In the processing D and the first embodiment in which the recording dot positions (grid points l1 and l2) are twice as low as the resolution in both the vertical and horizontal directions, four times the scanning is required. As described above, the method of recording the additional dots only at the diagonal grid points l1 of the data of the edge portion of the original image has the merit of not only improving the recording quality but also realizing high-resolution and relatively high-speed recording. is there.

(Embodiment 3) High-resolution data is recorded at a high resolution only at the edge portion 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 apparatus in advance, the first embodiment
The addition of dots (smoothing process) in STEP 6 shown in FIG. In the present embodiment, the high-resolution recording portion at the edge portion has high resolution as it is by appropriately thinning out the recording data of the portion other than the edge portion, and the portion other than the edge portion has no substantial reduction in resolution. It is possible to reduce the recording density of ink droplets.

FIG. 21 is a flowchart showing a process for thinning out input data when the input data is high-resolution data having the second resolution.

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

In STEP 12, an edge portion (edge area) of the input low-resolution data is detected. STEP
Reference numeral 13 denotes a data thinning process (conversion), which converts input data in an area other than an edge portion so as to appropriately thin the recording data. A simple method is to convert print data so that ink droplets of a color to be printed in a half resolution area, here a 360 dpi angle area, have a maximum of two dots. The simplest method is to thin out data of two diagonal dots. The data for thinning out obtained by this processing (the dot to be thinned out is 0 and the others are 1) is data A.

At STEP 14, the data at the edge portion and the data at the non-edge portion are combined. Specifically, data A for thinning obtained from data that was not an edge portion
Is ANDed with the edge data, that is, the input data, to obtain recording data.

Thereafter, recording is performed in the same manner as in the first embodiment.

(Embodiment 4) Low-resolution printing is performed on adjacent portions of different colors. In the first embodiment, a case where printing is performed in a single color has been mainly described. However, in color printing, printing is performed using two or more colors of ink. When two or more different colors of ink are printed adjacent to each other, an adjacent portion of a different color has an edge portion in a single color, but does not have an edge portion as a recording region.

In this embodiment, adjacent portions of different colors are recorded by the same processing as 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 16 × 12 dots of each color. In the area adjacent to Bk and Y, the area where the logical OR data of the Bk data and the Y data is not an edge is processed so that each color is not an edge, and the recording density of ink droplets is reduced.

FIG. 22 is a flowchart showing a process of converting input data into high-resolution data having a second resolution when the input data is low-resolution data having a first resolution, and performing smoothing and thinning-out processing. In the figure, STEP
Steps 21 to 27 are the same as steps 11 to 17 in FIG.

In STEP 21, low-resolution data is input.
If it is determined in STEP 22 that the frame is an edge portion, the STE
In P28, it is determined whether or not it is a different color boundary portion. Here, 4
A case where two or more layers are adjacent is determined as a boundary part. For example, since it is determined that the region A1 is not a different-color boundary portion, the process proceeds to STEP 25 as in FIG. 8, but since the region A2 is determined to be a different-color boundary portion, the process proceeds to STEP 23 to perform a thinning process.

(Embodiment 5) Another method of thinning out FIG. 23 showing Embodiment 5 shows another example of how to thin out data in the non-edge portion shown in FIG. In this embodiment, low-resolution data is used for a non-edge portion instead of using high-resolution data. The dots for high-resolution recording are 20 ng, and the dots for low-resolution are 40 ng. Therefore, if one dot of low-resolution data is used instead of two dots of high-resolution data, the same thinning effect can be obtained. .

(Embodiment 6) In the case of using a recording head of another system FIG. 7 shows an example of a serial type inkjet color printer to which the present invention is applied.

The print head 1 is a device that has a plurality of nozzle rows and performs image recording by forming dots on a recording medium by discharging ink droplets. In this embodiment, a piezo element, which is an electromechanical converter, is used to positively generate ink droplet diameters of different sizes (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. Further, different color inks are ejected from different print heads, and a color image is formed on a recording medium by mixing colors of these ink droplets. Print head row 1K (black), 1C (cyan), 1M
(Magenta) and 1Y (yellow) are mounted on the carriage 201, and an image is formed on a recording medium in this order during one scan in one direction.

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

The carriage 201 moves on a sliding shaft by transmitting the power from the carriage driving motor 8 by the belts 6 and 7. Printing in the digit direction is performed during the operation in the main scanning direction. The recovery unit 400 has a function of always maintaining the state of the print head in a good state, and in a non-print state, the cap row 420 closes the ejection surface of the print head to prevent drying or the like. Therefore, the carriage 201 is moved to the recovery unit 400.
Is called a home position (hereinafter, HP). In the normal printing operation, the carriage moves from this HP to perform printing, and in this example, printing is performed from left to right in FIG. In the sub-scanning direction, the recording medium is fed by a paper feed motor (not shown). The direction A in the drawing is the paper feeding direction. Reference numeral 9 denotes a flexible cable for supplying an electric signal to the recording head. The ink is supplied from the ink cassettes 10K, 10C, and 10C mounted on the carriage 201.
Performed from 10M, 10Y. The supply of ink is not limited to the configuration shown in the drawing, and a configuration in which a row of tubes for supplying ink is provided in the same manner as a flexible cable from the ink tank provided in the recording apparatus body to supply a print head on the carriage for each color. It may be.

FIG. 5 shows details of the recording head shown in FIG. As a configuration of the recording head, for example, a recording head having a configuration using an electromechanical transducer as disclosed in Japanese Patent Application Laid-Open No. 63-237669 is used. By using the piezoelectric element 38 which is an electromechanical transformation, it is possible to obtain two different ink volumes by changing the driving conditions for driving the piezoelectric element. The driving condition is to control a voltage value or a driving time, which is driving energy, or may be a driving waveform.

(Summary) The features of each of the above embodiments are summarized as follows. Depending on the recording mode, high-resolution recording and low-resolution recording are selectively used and recorded. The recording mode can be set manually or automatically,
Switching can be performed on a page basis or within a page.

1. High-resolution data is recorded from low-resolution data.

Means for detecting an edge portion of recording data; means for converting low-resolution data into high-resolution data which is twice as long and wide;
It has means for ejecting about one-half of the unit ink droplet at the time of low-resolution printing, and smoothing processing means. The edge portion of the input low-resolution data is subjected to smoothing processing. The area is recorded at a high-resolution recording position with up to four ink droplets, and the portion of the low-resolution data other than the edge portion is up to 2 units in the same unit area for each color.
Record with individual ink drops.

2. High-resolution data is limited to edge portions only.
Non-edge portions are recorded with 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 resolution reduction processing to reduce the number of recording dots (the number of ink shots on the recording medium). It is possible to prevent ink overflow and to increase the recording speed.

3. In the above 1 and 2, when printing two or more kinds of inks of different colors, adjacent portions of different colors are printed by the same processing as printing at low resolution.

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

5. The edge portion is an area of 1 to 10 pixels from the outermost edge 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 a low-resolution recording mode or a high-resolution recording mode. If the input data is low-resolution data in the recording mode, it is recorded as it is.

When the recording resolution is a low resolution recording mode,
If the input data is high-resolution data, the input data is recorded with appropriate thinning.

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

When the recording resolution is a high-resolution recording mode,
If the input data is high-resolution data, the input data is recorded with appropriate thinning.

As described above, according to each embodiment, ink droplets having a slightly smaller volume are ejected, and the recorded ink does not overflow on the recording medium. It is possible to record at a resolution.

Further, high-resolution recording on plain paper can be performed. The fact that recording is possible at high resolution also means that recording is possible with high gradation.

Further, even when the input data is high-resolution data, the data other than the edge portion can be recorded with the high resolution by appropriately thinning out the data.

(Others) The present invention particularly provides an excellent effect in a recording apparatus using an ink jet recording head which forms flying droplets by utilizing thermal energy and performs recording, among ink jet recording methods. It is.

The typical structure and principle are described in, for example, US Pat. Nos. 4,723,129 and 4,740.
It is preferable to use the basic principle disclosed in the specification of Japanese Patent No. 796. This method is a so-called on-demand type,
Although it can be applied to any type of continuous type, in particular, in the case of the on-demand type, it can be applied to a sheet holding liquid (ink) or an electrothermal converter arranged corresponding to the liquid path. By applying at least one drive signal corresponding to recording information and giving a rapid temperature rise exceeding nucleate boiling, heat energy is generated in the electrothermal transducer, and film boiling occurs on the heat acting surface of the recording head. Liquid (ink) corresponding to the drive signal
This is effective because air bubbles in the interior can be formed. By discharging the liquid (ink) through the discharge opening by the growth and contraction of the bubble, at least one droplet is formed. When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of a liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further, if the conditions described in US Pat. No. 4,313,124 relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.

The configuration of the recording head may include a combination of a discharge port, a liquid path, and an electrothermal converter (a linear liquid flow path or a right-angled liquid flow path) as disclosed in the above-mentioned respective specifications. U.S. Pat. No. 4,558,333 and U.S. Pat.
A configuration using the specification of Japanese Patent No. 59600 is also included in the present invention. In addition, Japanese Unexamined Patent Application Publication No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of an electrothermal transducer for a plurality of electrothermal transducers, and an aperture for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the configuration is based on JP-A-59-138461, which discloses a configuration corresponding to a discharge unit. That is, according to the present invention, recording can be reliably and efficiently performed regardless of the form of the recording head.

In addition, even in the case of the serial type as described above, the recording head fixed to the apparatus main body or the electric head connected to the apparatus main body or the ink from the apparatus main body is mounted on the apparatus main body. 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 provided integrally with the recording head itself is used.

It is preferable to add ejection recovery means for the recording head, preliminary auxiliary means, and the like as the configuration of the recording apparatus of the present invention since the effects of the present invention can be further stabilized. If these are specifically mentioned, the recording head is heated using capping means, cleaning means, pressurizing or suction means, an electrothermal transducer, another heating element or a combination thereof. Pre-heating means for performing the pre-heating and pre-discharging means for performing the discharging other than the recording can be used.

Further, as for the type and number of the 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 printing mode of the printing apparatus is not limited to a printing mode of only a mainstream color such as black, but may be any of integrally forming a printing head or a combination of a plurality of printing heads. The present invention is also very effective for an apparatus provided with at least one of the recording modes of full color by color mixture.

In addition, in the embodiments of the present invention described above, the ink is described as a liquid. However, an ink which solidifies at room temperature or lower and which softens or liquefies at room temperature may be used. In general, the ink jet method generally controls the temperature of the ink itself within a range of 30 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is in a stable ejection range. Sometimes, the ink may be in a liquid state. In addition, in order to positively prevent temperature rise due to thermal energy by using it as energy for changing the state of the ink from a solid state to a liquid state, or to prevent evaporation of the ink, the ink is solidified in a standing state and heated. May be used. In any case, the application of heat energy causes the ink to be liquefied by the application of the heat energy according to the recording signal and the liquid ink to be ejected, or to start solidifying when it reaches the recording medium. The present invention is also applicable to a case where an ink having a property of liquefying for the first time is used. In such a case, the ink
JP-A-54-56847 or JP-A-60-7
As described in Japanese Patent Publication No. 1260, it is also possible to adopt a form in which the sheet is opposed to the electrothermal converter in a state where it is held as a liquid or solid substance in the concave portion or 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, the form of the ink jet recording apparatus of the present invention is not limited to those used as image output terminals of information processing equipment such as computers, copying apparatuses combined with readers and the like, and facsimile apparatuses having a transmission / reception function. It may take a form.

[0121]

According to the present invention, low-resolution or high-resolution input data is converted into recording data for driving a recording head having a resolution corresponding to a recording mode, and recording set based on the converted recording data. Since recording according to the mode can be performed, high-quality recording can be performed regardless of the resolution of the input data.

[Brief description of the 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 sectional view of a recording head.

FIG. 4 is an enlarged 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 illustrating an example in which edges of four layers are processed as edge portions.

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

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 to a high resolution.

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

FIG. 16 is a diagram illustrating print data according to the first embodiment.

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

FIG. 18 illustrates a process according to the second embodiment.

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

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

FIG. 21 is a diagram illustrating a flowchart of a third embodiment.

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

FIG. 23 is a diagram illustrating recording data according to a fifth embodiment.

[Explanation of symbols]

 Reference Signs List 20 color ink tank 21 black ink tank 22 discharge port surface 23 discharge port 30 heating element 31 recording medium 35 ink droplet 38 piezoelectric element 100 recording device 101 carriage 102 recording head 103 recording head unit 300 mode discriminating means 301 first droplet discharge Setting means 302 first recording condition setting means 303 recording apparatus control system 304 second droplet discharge setting means 305 high resolution processing means 306 data partial processing 307 second recording condition setting means

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI H04N 1/52 H04N 1/46 B (72) Inventor Masao Kato 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-6-8476 (JP, A) JP-A-5-96721 (JP, A) JP-A-3-275371 (JP, A) JP-A-4-365181 (JP, A) JP-A-4-30971 (JP, A) JP-A-5-229176 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41M 5/00 B41J 2/05 B41J 2/21 G06T 1/00 G06T 11/00 H04N 1/52

Claims (15)

(57) [Claims] 1. An ink jet recording method for performing recording using a recording head that discharges ink, comprising: a first recording mode in which recording is performed by discharging a relatively large amount of ink at a low resolution; A second recording mode for performing recording by ejecting a small amount of ink is set, and low-resolution or high-resolution input data is converted to a resolution corresponding to the set first or second recording mode. An ink jet printing method comprising: converting print data for driving a print head; and performing print control in accordance with the print mode set by the setting unit based on the converted print data. 2. The method according to claim 1, wherein 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 only a continuous area of the converted high-resolution data is converted. 2. The ink jet recording method according to claim 1, wherein the data is converted into thinned data. 3. An ink jet recording apparatus which performs recording using a recording head which discharges ink, comprises: a first recording mode in which a relatively large amount of ink is discharged at a low resolution to perform recording; Setting means for setting a second printing mode for performing printing by ejecting a small amount of ink, and inputting low-resolution or high-resolution input data to the first or second printing set by the setting means. Mode
Conversion means for converting the data into print data for driving the print head having a corresponding resolution; and print control for performing print control in accordance with the print mode set by the setting means based on the print data converted by the conversion means. And an ink jet recording apparatus. Wherein said converting means is set second recording mode is, when the input data is low resolution data, converts the input data into high resolution data, the high converted
Converts only the continuous area of the resolution data to thinned data
An ink jet recording apparatus according to claim 3, wherein the that. 5. The conversion means adds data to an edge portion of low-resolution input data, and a portion other than the edge portion includes:
5. The ink jet recording apparatus according to claim 4, wherein the input data is converted into high-resolution data as it is or by adding the input data so as to be recorded twice. 6. The image processing apparatus according to claim 1, wherein the converting means includes: a data input / output section for inputting the low-resolution input data;
6. The ink jet recording apparatus according to claim 5, wherein data is added to an edge portion of the input data by adding data to an intermediate position only in a diagonal direction. 7. An ink jet recording apparatus according to claim 4, wherein said conversion means converts only data of a portion other than an edge portion into thinned data. 8. An ink jet recording apparatus according to claim 5, wherein said edge portion is a peripheral area of a recording area. 9. An ink jet recording apparatus according to claim 8, wherein said edge portion is a peripheral area of logical sum data of a plurality of color data in the case of a plurality of colors. 10. An ink jet recording apparatus according to claim 3, wherein said conversion means converts the input data to thinned data when the first mode is set and the input data is high-resolution data. 11. An ink jet recording apparatus according to claim 10, wherein said conversion means converts only data of a portion other than an edge portion into thinned data. 12. An ink jet recording apparatus according to claim 11, wherein said edge portion is a peripheral area of a 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 a plurality of color data in a case of a plurality of colors. 14. The ink jet recording method according to claim 1, wherein the recording head ejects the ink using thermal energy. 15. The ink jet recording method according to claim 1, wherein the recording head discharges the ink using mechanical energy.