JPH081962A - Inkjet recording apparatus and inkjet recording method - Google Patents

Abstract

(57) [Abstract] [Purpose] Achieves both low-resolution and high-resolution image formation without the need for a special recording head, and increases the number of dots to be recorded when forming a high-resolution image. It prevents the life of the recording head from being shortened. [Structure] One dot of dots printed at low resolution is printed with ink droplets (d4, d
High resolution recording is performed by arranging a plurality of 5). Further, with respect to dots that are continuous in the vertical and horizontal directions, low resolution recording is performed using normal print dots (d1) to prevent deterioration in the life of the recording head without degrading image quality.

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 apparatus for ejecting ink to form an image on a recording medium, and an ink jet recording method. More specifically, the present invention relates to an inkjet recording apparatus and an inkjet recording method capable of achieving both high image quality and high-speed printing.

[0002]

2. Description of the Related Art In recent years, office automation equipment such as personal computers and word processors have become widespread. As a method of outputting information input by these equipments onto a recording medium, for example, a wire dot method, a thermal transfer method, an ink jet recording method, etc. Various recording methods have been developed and put to practical use. In these recording methods, the print heads of the respective methods form a predetermined image on the conveyed recording sheet, and there are remarkable differences between the print heads. Among them, the ink jet recording method is a recording method which has been attracting attention in recent years because it is less in contact with the recording medium and thus produces less noise and is effective in achieving high image quality and high resolution.

The structure of the print head in the ink jet recording system includes a sheet holding ink,
There is a configuration in which an electric / heat conversion body is arranged corresponding to a liquid path (nozzle) of ink. In this configuration, by applying a drive signal corresponding to the recorded information to the electric / heat converter, heat energy is generated in the electric / heat converter that causes a rapid temperature rise in the adjacent ink beyond nucleate boiling. Let
Film boiling is caused on the heat-acting surface in the nozzle of the print head, and as a result, air bubbles are formed in the ink in the nozzle in unison with the drive signal. If this drive signal is made to have a pulse shape, bubbles are appropriately formed and contracted immediately, so that it is possible to achieve ink ejection with excellent responsiveness.

As another construction of the ink jet recording system, an electric / mechanical converter (referred to as a heater) is provided in the ink flow path or in the vicinity of the ink flow path, and the electric / mechanical converter responds to recorded information. By applying a voltage, electricity
A method of forming an image by ejecting ink droplets by a mechanical pressure generated by a mechanical converter is also known. A piezo element is widely known as an electromechanical converter as a means for generating this ejection energy.

As an invention for providing a high-definition image by the ink jet recording system, Japanese Patent Publication No. 54-41.
No. 329 discloses a configuration that realizes images (characters) having different dot pitches (resolutions) by using dots of different sizes, without decreasing the printing speed. It should be noted that in the present invention, there is no description that recording can be performed without clearly lowering the printing speed, and there is no technical disclosure for reducing the number of times the head is driven.

[0006]

However, as the resolution for high image quality is increased, the unit pixel forming the image becomes smaller, and the print dot diameter forming the unit pixel also becomes smaller. Further, in order to record the same area of the recording area by printing dots, a large number of dots are required. For example, 360 dpi (dots per inc
In the case of recording with a resolution of “hes”, 360 × 360 dots are printed per square inch, whereas in the case of high resolution recording, for example, 720 × 360 (dpi), 7
When recording is performed at a density of 20 × 720 (dpi), the number of dots per unit area is 2 to 4 times. The drive frequency of the print head in normal recording is set to such an extent that recording can be performed without unstable ejection. In the case of high resolution, 2 to 4 times as many dots are printed as compared with normal resolution printing. Therefore, in order to perform high resolution printing without lowering the printing speed, the drive frequency of the print head should be doubled. It is necessary to increase four times. If the drive frequency is higher than the performance of the print head, unstable ejection may occur, and abnormal temperature rise may occur in the print head head that uses the electric / thermal converter, resulting in extremely poor print quality. Will end up. Therefore, there is a drawback that the printing speed is reduced when high density recording is performed.

Further, since the number of print dots increases during high resolution recording, a large amount of energy is applied to the print head. As for the ejection energy when ejecting ink, not all of the input energy is consumed for ejecting ink. In particular, in the method of ejecting ink by thermal energy using the above-mentioned electric / thermal converter, residual energy is accumulated in the vicinity of the ink ejection portion of the print head, and this extra thermal energy raises the temperature of the print head. I will end up.
The ink used for recording has a thermal dependency on the physical properties related to the ejection amount such as the viscosity of the ink, and adversely affects the control of the ink ejection amount by accumulating excess heat in the print head. As a result, there is a drawback that the recorded image becomes non-uniform.

Further, when ink droplets of different sizes are ejected from the same nozzle, if the ink droplets of different sizes are mixed and ejected during the same scan, the ejection stability of the ink droplets becomes disadvantageous. I will end up. This is because the inkjet method has an ink ejecting means such as an electricity / heat converter in the ink flow path, and therefore, when ink droplets of different sizes are ejected, inconsistent ink flow in and out of the ink flow path may occur. This is because the ink ejection stability is disturbed by the occurrence.

The life of the print head is almost regulated by the number of ejections. In high-density printing, the number of dots arranged in the same area is much larger than that in a low-resolution image, and the number of dots that can be recorded by one print head is reduced by performing high-density printing. Therefore,
When high-density printing is performed, the life of the print head is shortened as compared with low-resolution printing, and as a result the number of times the print head is replaced increases, which increases running costs.

As the best mode for carrying out the present invention, there is a case where recording with different resolutions is performed with different dot diameters depending on the recording medium. In this case, since the grid points are shifted depending on the resolution, a slight shift on the recorded image may be conspicuous if printed as it is.

In the double-strike mode in which the same dot is recorded twice at the same position as a measure for improving the print density, when ink droplets of the same size are recorded at the same position, the high density recorded portion is rather deteriorated by ink bleeding. There was a case where it ended up.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and achieves both low-resolution and high-resolution image formation without requiring a special recording head. The purpose is to It is another object of the present invention to prevent the life of the recording head from being shortened due to an increase in the number of dots to be recorded when forming a high resolution image.

In order to achieve the above-mentioned object, the present invention changes the print mode in which the size of the recording dot is different according to the kind of the recorded image, so that the portion requiring the high density recording becomes the unnecessary portion. The feature is that they are separated to realize high-speed recording.

Further, the present invention is characterized in that a certain area in a high-density image is recorded in low density, that is, converted into large dots and recorded.

Further, according to the present invention, the arrangement of different dot diameters can be moved / adjusted in the main scanning direction and the sub scanning direction in units of ¼ of the print head pitch. Further, it is characterized in that it is possible to move and adjust in the main scanning direction and the sub scanning direction by using two heads which are shifted by 1/2 unit of the print head pitch in the sub scanning direction.

Further, according to the present invention, in the double-stroke mode,
It is characterized in that the first printing and the second printing are recorded by using ink droplets having different sizes or ink droplets having different resolutions.

[0017]

【Example】

(First Embodiment) FIG. 7 shows an example of a serial type inkjet 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. 6B is a diagram showing the configuration of the print head array and ink tank for each color. 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 forming a green (hereinafter G) image in the order C, Y,
When forming a blue (hereinafter B) image, ink droplets are landed in the order of C and M to form a color image.

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.

FIG. 23 is a functional block diagram of the recording apparatus in this embodiment. The recording device which has received the recording data or the print mode data as the data for determining the recording mode determines which recording mode is to be performed by the recording mode discrimination means 501. The criteria for determining the recording mode is
It is performed according to the type of recorded image. For example, 1. Whether or not the recorded data is characters, 2. Whether the recorded data is a black image or a color image, Low resolution or high resolution, 4. 4. Which recording medium is selected, The recording mode can be determined based on whether or not it is bit image data (only high resolution printing of bit image data). Now, when the high-density printing mode which is the second recording mode is selected, the conditions of the print head driven by the "second droplet discharge setting 502" (in this case, the driving conditions for discharging small dots), etc. Is set. In the next "high resolution processing 503", processing for converting the data given corresponding to the normal print density into print data corresponding to high resolution printing, and the like are performed. In the subsequent "data partial processing 504", small dot data generation processing and the like are performed at positions that did not exist in the low resolution data. Then, "second recording condition setting 505"
The detailed print mode conditions are determined for each section. That is, the amount of conveyance of the recording medium, the moving speed of the carriage, the number of printing passes, and the like. The "recording apparatus control system 508" receives these pieces of information, and actually controls the drive of the print head and the drive of the recording medium transport motor. These controls perform data expansion for several lines of the print head, and since the main body has information for several scans in advance, the print mode can be switched for each scan of the carriage. There is. The above-mentioned recording mode discrimination criteria can be changed according to the purpose of image output.For example, high resolution recording is not always performed for characters and black images. Other than the image, the high resolution recording mode may be set. Further, the recording mode is manually set, and the discriminating means 5
The configuration determined by 01 is also included in this embodiment.

Of the above-mentioned series of processing, a part or all of the processing up to the front of the recording apparatus control system is a device capable of transmitting / receiving data to / from the recording apparatus without the recording apparatus main body, such as a host computer. It may be processed.

<Multi-pass recording method (fine recording method)> In printing an image, various elements such as color developability, gradation and uniformity are required. Particularly regarding uniformity, a slight variation in nozzle unit that occurs during the print head manufacturing process affects the ejection amount and ejection direction of each nozzle when printing, and eventually results in uneven density of the printed image. It causes deterioration of image quality.

An example of density unevenness will be described with reference to FIGS. 18 and 19 using a single-color print head as an example for simplification.
FIG. 18 shows an example of printing by a recording head having uniform characteristics such as ejection amount and ejection direction without variations in nozzle units.
In FIG. 18A, reference numeral 91 denotes a print head, which is constituted by eight nozzles for simplification. 9
Reference numeral 3 is an ink droplet ejected by the multi-nozzle 92, and it is ideal that ink is ejected in a constant direction with a constant ejection amount as shown in the figure. If such ejection is performed, dots of uniform size are landed on the paper surface as shown in FIG. 18B. FIG.
(C) shows the relative recording image density of each recording dot, and as is clear from the figure, a uniform image without density unevenness is obtained as a whole.

However, in reality, as described above, each nozzle has a variation, and if printing is performed in the same manner as described above, as shown in FIG. 19A. The size and direction of the ink drop ejected from each nozzle vary, and the ink drop lands on the paper surface as shown in FIG. 19B. FIG.
In (b), due to variations in the ejection characteristics of the print head, white streaks occur in the white paper (unprinted) portion where ink does not land and the area factor 100% cannot be satisfied in the head main scanning direction. On the contrary, it is shown that dots are overlapped more than necessary and black streaks are generated in a portion where the print density is high. A collection of dots landed in such a state is shown in FIG.
The density distribution is as shown in (1), and as a result, these phenomena are usually perceived as density unevenness as seen by human eyes. Also, streaks due to variations in the paper feed amount may be noticeable. The method will be briefly described with reference to FIGS. According to this method, printing is performed by scanning the print head 91 three times in order to complete the print area shown in FIGS. 18 and 19, and the area of 4 pixel unit which is half of the print width of the print head is Completed in two consecutive passes. In this case, the 8 nozzles of the print head are divided into two groups, that is, the upper 4 nozzles and the lower 4 nozzles, and the dots printed by one nozzle in one scan are specified image data according to a predetermined arrangement. It is thinned out to about half. After the paper is fed during the second scan, dots are embedded in the remaining image data that was not printed in the first scan using a nozzle different from that used in the first scan, and complementary printing is performed. The printing of the pixel unit area is completed. The recording method as described above is called a fine recording method. When this recording method is used, even if a head having different ejection characteristics is used as in the print head shown in FIG. 19, an image is formed in the same recording area by a plurality of nozzles, and therefore printing with characteristics unique to each nozzle is performed. Since the influence on the image is reduced, the printed image becomes as shown in FIG. 20B, and the black stripes and the white stripes as shown in FIG. 19B are not noticeable. Therefore, as shown in FIG. 20 (c), the density unevenness seen on the recorded image is considerably reduced as compared with the example of FIG.

When performing fine recording as described above, in the first scan and the second scan, the image data is divided according to a certain arrangement so as to be complementary to each other. What is a pattern?
As shown in FIG. 1, it is the most general to use a staggered grid for every vertical and horizontal pixel. Therefore, in the unit printing area (here, in units of 4 pixels), printing is completed by the first scan for printing the zigzag lattice and the second scan for printing the inverse zigzag lattice. 21 (a), 2
1 (b) and 21 (c) are print heads having 8 nozzles, similar to FIGS. 18 and 19, showing how recording of a certain area is completed when the staggered and inverted zigzag patterns are used. It was explained using. First, in the first scan, a staggered pattern is printed using the lower four nozzles as shown in FIG. Next, in the second scan, as shown in FIG. 21B, the paper is fed by 4 pixels (1/2 of the total nozzle width) to record an inverted zigzag pattern. Further, in the third scan, as shown in FIG. 21C, the paper is fed again by 4 pixels (1/2 of the total nozzle width), and the staggered pattern is printed again. In this way, the paper feeding in units of 4 pixels and the recording of the staggered pattern and the reverse zigzag pattern are alternately performed in this manner to complete the recording region in units of 4 pixels for each scan. As described above, by printing in the same region with two different types of nozzles, it is possible to obtain a high-quality image with reduced density unevenness. In addition, various mask patterns for thinning other than zigzag and reverse zigzag may be used depending on the purpose. Also, instead of completing printing in the printing area by scanning twice,
For example, printing may be performed using a pattern that is complementary by scanning three times or four times.

Next, image formation in the embodiment of the present invention will be described.

Image formation in this embodiment is performed mainly by switching between two print modes. One is a high-speed printing mode that prints at normal pixel density (it is called high-speed printing because printing can be done at higher speed than high-density recording).
The other is a high-density printing mode for printing with high resolution. Further, the high-speed printing mode has a low resolution as compared with the high resolution, and is therefore referred to as a low resolution mode.

<High Speed Printing Mode> First, the high speed printing mode of this embodiment will be described.

In the high-speed printing mode of this embodiment, all the ejection nozzles of the print head are used and printing is performed during one scan (hereinafter, one-pass printing). FIG. 14 is an example of 1-pass bidirectional recording, and shows a case where the print head has 16 ejection ports. The high-speed printing mode of this example is defined as a mode for printing a low-resolution image, and the recording dots in FIG. 14 have a recording density of 360 dpi in both vertical and horizontal directions (main scanning and sub scanning). In the case of this example, the interval (pitch) between the ink ejection ports in the print head corresponds to the low resolution. Since the recording density is low, the ink droplet diameter per unit pixel is preferably larger than that in high resolution printing. Although it depends on the characteristics of the ink, in the present embodiment, the ratio of the volume of ink droplets to be ejected is set to the dots ejected for low resolution recording (large ink droplets) and the relatively small dots ejected for high resolution recording (small Ink drop) and the ratio is approximately 2: 1. In this example, the ejection amount of large ink droplets is about 80 pl, and the ejection amount of small ink droplets is about 40 pl. As shown in FIG.
The dot arrangement of the low resolution image recorded by pass printing is shown in detail. The horizontal direction in the figure is the main scanning direction in which the carriage moves, and the vertical direction is the recording medium conveyance direction and the sub-scanning direction in which the ink ejection ports are lined up. The intersections of the vertical and horizontal lines shown by the dotted lines in this figure are the grid points at a recording density of 360 dpi. In the printing example of FIG. 8, the dots shown in d1 are arranged only on the grid points of 360 dpi to form an image. The number of dots forming the image shown in FIG. 8 is 40 for large ink droplets.

<High Density Printing Mode> Next, the high density printing mode of this embodiment will be described.

FIG. 9 shows an example in which the recorded image of FIG. 8 is recorded at 720 dpi, which is twice the image density in the main scanning direction. With this printing method, the original image is 360 dp
Even at a resolution of i, pseudo high resolution recording is achieved by adding or reducing recording dots in the main scanning direction. In the example shown in FIG. 9, 360 in the main scanning direction.
Two dots are arranged in one pixel having a pixel density of dpi. Figure 9
However, the intersection of the vertical and horizontal lines indicated by the dotted line is a 360 dpi lattice point. The dots (d in Fig. 9) filled with gray
2) is a recording dot arranged on the grid point,
The dots indicated by the diagonal lines shown by d3 are 720 dp from the grid point.
i indicates that the print dots are displaced from each other.

The number of recording dots forming the image shown in FIG. 9 is 80, which is double that of the image shown in FIG. As a specific printing method for performing high-density printing in the main scanning direction as shown in FIG. 9, the frequency of ink ejection is the same as in the normal printing mode, and the movement speed of the carriage equipped with the print head is set to the normal printing mode. There is a way to halve the mode. Alternatively,
Using the multi-pass printing method described above, printing is performed without thinning out data, and the printing dots at the time of the second scan are shifted by half a pixel in the main scanning direction from the positions of the printing dots at the first scan. High density recording can also be achieved by recording. FIG. 15 shows a method of increasing the recording density in the main scanning direction by the latter method.
The dot (d2) painted in gray in FIG. 9 is 360 dp.
Recording dots arranged at grid points of i, and forward scanning shown in FIG. 15 (scanning from left to right in the drawing for printing)
Record at. Also, the dot d indicated by the diagonal lines in FIG.
Reference numeral 2 is a recording dot arranged by shifting a half pixel of 360 dpi from the recording position of the dot d1, and recording is performed by backward scanning (printing from right to left in the drawing). Since the recording density in each scan of the reciprocating scan is 360 dpi and the normal low resolution recording is still performed, the carriage moving speed and the ink ejection frequency may be the low resolution recording. As a result, since the recording area is divided and recorded in a plurality of times, the time for image recording on the same area is delayed by the number of divisions as compared with the high-speed printing mode, but as described in the above-mentioned multi-pass printing, raster is used by using different nozzles. Since the image is formed in one direction, there is an effect of reducing density unevenness due to variations in the ejection characteristics of the print head.

In the present example, the above-described two print modes are switched depending on whether or not the image type is character data. Since the normal character data includes a common control code, it is possible to determine whether or not a character exists in the image data by detecting this information. This detection unit may be performed by a host computer (CPU) that handles image data, or the detection unit may be provided inside the printing apparatus. Since the character data has continuous shaded portions and curved portions, it is possible to achieve high image quality by using the above high-density printing mode. Since it is assumed that there are relatively many isolated dots for images other than character data, the high-speed printing mode (low-resolution recording) is performed.

The functional block diagram shown in FIG.
The data input at 1 is judged. As described above, the criterion for the determination includes whether the image is a black image, a color image, or a bit image. Further, it may be configured such that what kind of image is to be recorded by high-resolution recording can be switched by user's designation, and in this case, a recorded image desired by the user can be obtained. The determination of this data may be performed on the recording device side as described above, or may be performed on the host side.

By switching the print mode according to the image data in this way, it is possible to shorten the recording time by recording suitable for the image data. That is, high image quality recording is performed in a print mode with a low recording speed only for an image that requires high density recording, and the recording time can be shortened by using the high speed print mode for an image that has little problem even if the recording density is low.

Further, in the present embodiment, the timing of switching the recording mode is set in page units. 1
Switching the print mode while printing a page (see, for example, Figure 1
Since the printing method of No. 4 and the printing method of FIG. 15 are not switched), the printing speed is not changed even when a plurality of different types of image data are mixed in the same page. The switching timing is effective when the image data in the page is the same. Further, the type of image data in a page may be determined by the method of determining from the first data of the page or by referring to all the image data in the page and determining which image has a large proportion.

As described above, an image is formed with a different recording ink droplet diameter or a different ink ejection amount depending on the image data, and the recording operation is performed by switching the printing mode corresponding to the ink droplet diameter or the ink ejection amount printing mode. By doing so, it becomes possible to form an image with excellent recording quality for data to be recorded at high density.

Further, the recording time can be shortened as compared with the case where only high density recording is performed.

(Second Embodiment) In the present embodiment, based on the example of high-density printing described in the first embodiment, the ink discharge amount ejected at the time of low resolution recording and the ink ejection amount at the time of high resolution recording. An example in which the volume ratio with respect to the discharged amount is different is shown.

In the present embodiment, the ratio of the volume of the ejected ink droplets is the dot ejected for low resolution recording (large ink droplet) and the relatively small dot ejected for high resolution recording (small ink droplet). And, it is almost 4: 1. 360d
Approximately 80p in one pixel formed by pi x 360dpi
Assuming that 1 ink droplet is arranged, the ejection amount of a large ink droplet is about 80 pl, and the ejection amount of a small ink droplet is about 20 pl. Also in this embodiment, the high-density printing mode and the high-speed printing mode are separately printed as in the first embodiment, so that the printing time can be shortened corresponding to the kind of the recorded image and the high-density printing mode can be achieved. For an image requiring printing, it is possible to form a recorded image with high resolution and excellent recording quality.

FIG. 10 shows the dot arrangement in the high density print mode. Since the ejection amount ratio of dots of different sizes is 4: 1, instead of forming one dot of a large ink drop in one pixel of 360 × 360 dpi, 4 small ink drops are formed.
Will be arranged. Similar to FIG. 1 described above, the intersection of the vertical and horizontal dotted lines is a 360-dpi lattice point. Therefore, the dots arranged on the vertical and horizontal lines indicated by the solid line are 360 dpi.
The image is recorded at a position shifted by half a pixel (1 pixel at 720 dpi). The dots d4 filled in with gray are recorded in a density of 720 dpi in the main scanning direction and in a unit of 360 dpi in the sub scanning direction.
Further, the dot d5 indicated by diagonal lines is a dot recorded at a position where the dot d4 is shifted by half a pixel of 360 dpi in the sub-scanning direction. In this embodiment, 176 dots of small ink droplets are arranged for recording.

When the high-resolution recording image shown in FIG. 10 is obtained, the input recording data corresponds to the low-resolution image shown in FIG. 8, so the recording data for high-resolution recording is obtained. It is necessary to create. A procedure for obtaining image data for recording the high resolution image shown in FIG. 10 from the low resolution image data shown in FIG. 8 will be described below.

First, the original image data shown in FIG. 8 will be displayed with "original image data", "right of original image data", "below original image data", and "lower right of original image data" centering on the original image data. "
The data corresponding to the recording position of 4 times the original image is created at each of the four positions at a resolution of twice the vertical and horizontal directions. Then, based on the created data, if it is a 2-dot corner where the edge portions are continuous in both vertical and horizontal directions, 1-dot data in high resolution recording unit is added to the corner. However, if the edge portion is continuous for 4 dots or more in either the horizontal direction or the vertical direction, there is no additional data.

By the above processing, the image data of FIG. 10 is obtained from the image data of FIG. This method is also applied as an example of the smoothing process, and as the smoothing process itself, another method other than this method may be applied.

The recording method of this embodiment will be described with reference to FIG. In this embodiment, printing is performed with a pixel density of 720 dpi in the sub-scanning direction (recording paper conveyance direction) as well, so it is necessary to perform a paper feed operation that is shifted by half a pixel of 360 dpi in which nozzles are arranged. In this figure, the number of ink ejection ports in one head is 16. First, when printing is performed by scanning the print head from the left to the right in the drawing (forward scan), printing is performed at a pixel density of 360 dpi in the sub-scanning direction. It is indicated by a gray circle in FIG. Next, when printing is performed by scanning the head from right to left in the drawing (backward scanning), printing is performed at a position shifted by half a pixel of 360 dpi in the sub-scanning direction from the recording during forward scanning. That is, by setting the conveyance amount L of the recording medium to be 7.5 nozzles, it is possible to record the dot d5 indicated by the diagonal lines in FIG. In FIG. 16, white circles are shown for easy viewing. Subsequently, the recording medium is conveyed by the conveying amount L ′ (for 8.5 nozzles), and recording is performed at a density of 360 dpi in the sub-scanning direction. By repeating these operations, reciprocating scanning carries 16 nozzles, which is the entire ejection opening width. Like this 360dp
By using the conveyance of the recording medium shifted by half a pixel of i and the multi-pass recording method together, it is possible to perform high density recording of 720 dpi in both the main scanning direction and the sub scanning direction.

In the present embodiment, the type of the recording image that serves as the switching reference of the recording mode is switched depending on, for example, a color image or a black image. Generally, a high density recording of a black image is more effective than a color data in improving a printing result. This is because black is easily noticeable in a recorded image, and many black images require reproducibility of curved lines such as characters. Whether the image is a black image or a color image may be determined by analyzing the image data on the host computer, or the recording apparatus main body may be provided with this determination function. Further, the above-mentioned recording mode may be switched depending on whether or not there is data for driving the black head.

Further, the switching of the print mode is performed within the page in this embodiment. If the print mode is switched within the page, the line that requires high density recording (black image in this embodiment) is recorded at a high density of 720 dpi, and when the recorded image is changed to a color image, a low level as shown in FIG. Print in high-speed print mode of resolution. For color recording,
In some cases, the amount of ink is smaller than that of black ink droplets due to the occurrence of mixed colors such as secondary colors. As an example, color ink (C
When the ejection volume ratio of ink droplets having different sizes of MY) is 4: 1, the ratio is 40 (pl): 10 (pl).

FIG. 17 shows an example of the arrangement of images based on the print data assuming that the print modes are switched within the page. The image example shown in FIG. 17 shows an example in which a combination of a plurality of types of images is arranged on a recording medium. In this embodiment, since the print mode is determined based on the black image or the color image, the black image exists in the areas indicated by A, D, E, and G in FIG. If there is no black data in the other image areas,
Printing is performed in the low-resolution high-speed printing mode shown in.
However, in this example, the black image in the color image is black because priority is given to black. In addition to this, a case where there is only black data in one line may be defined as a black image. According to this definition, only the area A in FIG. 17 is in the high density recording mode, and in the other areas, the printing mode changes depending on the presence or absence of black data.

In the above example, the print mode may be switched depending on the type of the recorded image for each resolution. As an example thereof, switching may be performed depending on whether the resolution of the recorded image is higher or lower than the resolution of the print head, and a threshold resolution (360 dpi, 300 dpi, etc.) is set, and the resolution of the image data is higher than that. You may switch depending on whether it is low.

(Third Embodiment) FIG. 11 shows an arrangement example of dots printed by this embodiment. In this embodiment, in a region where the image data is continuous for a certain value or more, low resolution recording with a large dot is performed instead of high resolution recording with a small ink drop, and low resolution recording is performed in a recorded image. The dots of large ink droplets and the dots of small ink droplets for high-resolution recording are mixedly arranged.

In the example shown in FIG. 11, conversion is performed so that low-resolution recording is performed only on lines that are continuous in the vertical and horizontal directions, but the present invention is not limited to this. According to this embodiment, it is possible to achieve a long life of the print head.

As shown in the first embodiment, in the recording system using the piezo element as the ink ejecting means of the print head, the electro-mechanical conversion is performed by applying the drive signal to the piezo element, and the ink is Is ejected. Further, in the case of a system using an electric / heat converter as the ink ejecting means, heat is generated and bubbling is caused by energizing the heater portion as the ink ejecting means, and ink droplets are ejected from the ejection port. In either method, the number of ejections (the number of drivings)
If the amount is large, the ink ejection performance is changed due to mechanical or thermal abrasion or deterioration, and in the worst case, the ejection performance is deteriorated. Therefore, depending on the image type, the life of the print head (the number of recording media that can be printed by one head) can be increased by reducing the number of times the ink ejecting section is driven in a portion that does not need to be driven.

The printing method of the dot arrangement shown in FIG. 11 will be described. Similar to the example described above, the intersections of the vertical and horizontal lines indicated by the dotted lines are the lattice points of 360 dpi pixels, and the dots indicated by d1 and d4 are the dots recorded on the lattice points of 360 dpi in the sub-scanning direction. The dot indicated by d1 is a dot recorded with a low resolution of 360 dpi in the main scanning direction and the sub-scanning direction, and the dot indicated by d4 is recorded with a high resolution of 720 dpi in the main scanning direction. Also, the dot d5 indicated by diagonal lines is 360 dp
It is arranged at a position shifted by a half pixel in the sub-scanning direction from the grid point of i. As is clear from FIG. 11, since large and small dots are mixed in the same raster (main scanning direction), printing is performed in the following procedure. Hereinafter, description will be given with reference to FIG.

The dots d1 and d4 to be printed in a unit of 360 dpi in the sub-scanning direction are the dots d1 formed by a large ink drop which is first recorded at a low resolution in the forward scanning.
Is recorded, and then a small dot d4 that is recorded at high resolution is recorded in the backward scan that is the return scan of the carriage without transporting the recording medium. Then, the recording medium is conveyed by an L width, and a high-resolution dot d5 is recorded on a grid point which is shifted by a half pixel of 360 dpi in the sub-scanning direction. To mix dots with different resolutions in the main scanning direction in this way, low-resolution dots and high-resolution dots that are printed on the same grid point in forward and backward main scans in which the print medium is not conveyed Dots are recorded, and after the paper is conveyed, 360 dpi
It is only necessary to record a low-resolution dot at a position shifted by a half pixel from the grid point.

The printing example of the present embodiment shown in FIG.
A total of 97 dots of different sizes are arranged. On the other hand, as shown in FIG. 3, a total of 176 dots are recorded in a high-resolution image composed of small ink droplets. As described above, in an area where image data is continuous, for example, a line portion which is continuous in the vertical and horizontal directions as shown in this embodiment, by performing low resolution recording with a large ink droplet, dots of different large sizes can be formed in one image. The number of dots to be placed in a certain area by mixing
That is, the number of times the print head is driven can be reduced. actually,
A dot with a large ink droplet can print an area equivalent to a plurality of recording dots with a small ink droplet, although it depends on the ejection amount ratio with a dot with a small ink droplet. Can be significantly reduced. In addition, the area recorded with low resolution with large ink droplets is an area where image data is continuous, so when compared with an image recorded with high resolution, there is no significant difference except for the minute differences in the edge part. I can't.

With the configuration shown in this embodiment, the number of recording media (life) that can be recorded by the print head can be increased.

As another printing method, by arranging a print head capable of printing in the recording apparatus at a position where the pitch of the ink discharge ports is shifted by half the low resolution image pitch in the sub-scanning direction, the print head shown in FIG. Printing by three scans (assuming that each of the forward scan and the sub-scan is counted as one) can be performed by the two scans in the method described above. This print head is shown in FIG. Two ejection port arrays (1K, 1K ') are provided only for the black head, and one CMY ejection port array is provided. One of the black heads, head 1K ', is provided so as to be capable of printing at a position displaced by half a pixel (half the ink ejection port pitch) in the sub-scanning direction. Therefore, when high resolution recording is performed, the dot d4 shown in FIG. 11 is printed by the head 1K of FIG. 6A, and the dot d5 is provided next to it so as to be recordable at a position shifted by a half pixel. Printing can be performed at 1K 'during simultaneous scanning. In addition, dots of large ink droplets printed at low resolution are printed by the head 1K without transporting the printing medium. Since two black heads are provided, the number of print dots per head is reduced. The effect shown in the present embodiment is obvious by comparing the numbers of dots forming the image shown in FIGS.

In the above embodiment, the scan for ejecting a large ink droplet to form an image and the scan for ejecting a small ink droplet to form an image are divided into a low-resolution recorded image and a high-resolution recorded image. And are mixed. Since the scanning is divided into a plurality of scans, stable ink ejection can be performed with almost no disturbance of ink inflow that occurs when ink droplets of different ejection amounts are ejected at the same time.

(Fourth Embodiment) Up to the third embodiment described above, a plurality of small dots of small ink droplets are formed in one pixel on the low resolution instead of large dots of large ink droplets of low resolution. By arranging them individually, high density and high definition recording was realized. In the recorded image of FIG. 11, the small dot portion is moved in the lower right direction in the drawing as compared with the original image of FIG. This is a grid point with a pixel density of 360 dpi and 72
This is caused by arranging dots by mixing grid points having a pixel density of 0 dpi. This slight dot shift may be noticeable depending on the type of recording medium and image data. Therefore, in this embodiment, as the best mode of the present invention, the positions where the dots of the large ink droplets and the dots of the small ink droplets are arranged are set so as to reduce the deviation of the dot arrangement due to the resolution. In FIG. 12A, scanning in which a large dot is printed as a small dot is divided and the printing start timing itself is shifted to correct the deviation in the main scanning direction. If the position where the carriage 201 shown in FIG. 7 starts printing is shifted by ¼ pixel in 360 dpi as one pixel unit between the print scanning for performing low-resolution recording and the print scanning for performing high-resolution recording, FIG. It is possible to arrange large and small dots like the gray circles in (a). In FIG. 12B, the number of recording dots of low resolution is set to 1 pixel in 360 dpi.
The case where printing is started by shifting by / 4 pixel in the main scanning direction is shown. 12A and 12B, it is clear that the positional relationship between the dots by the low resolution recording and the dots by the high resolution recording has become appropriate as compared with FIG.

Further, as shown in FIG. 6A, two black heads, which are provided so as to be capable of printing at positions shifted by half a pixel, are used, and 360 dpi is used as a pixel unit in the sub-scanning direction, and only 1/4 pixel is used. It is also possible to print dots at shifted positions. An image forming process using the head having such a configuration will be described with reference to FIG. First, the two heads as described above are driven together by carriage scanning in the forward direction to record the high-resolution recording dot d6 shown in FIG. Next, taking the print head shown in FIG. 9 as an example, the sub-scan feed amount L is set to L = 16 / 2-1 / 4 = 7.75 (pixels), and the recording medium is conveyed. Next, by carriage scanning in the backward direction, one of the black heads 1K and 1K 'shown in FIG. 6A is used to perform low-resolution printing at an image density of 360 dpi in the sub-scanning direction. The dots printed by scanning in the sub direction are shown in FIG.
It is a dot indicated by a dot d7 inside. In preparation for the next recording, the recording medium is conveyed by the conveyance amount L '= 16/2 + 1/4 = 8.25 pixels, and printing is performed by scanning in the forward direction. In this way, in the forward scan, only small ink droplet dots by high resolution recording are printed, and in the sub scanning direction, only large ink droplet dots recorded at low resolution are printed, so that large dots in the sub scanning direction are 360 dpi. Two dots formed by ink droplets are arranged at a pixel pitch of 720 dpi while the pitches are arranged. Like this
4 times the density of the print head pitch (1/360 of 360 dpi)
Since it is possible to arrange the low resolution recording dots and the high resolution recording dots in units of 4 pixels, it is possible to obtain good printing results without image shift.

(Fifth Embodiment) In the present embodiment, in the double-strike mode, by arranging ink droplets at different size dots or different resolution dot positions, the density of an image can be reduced without lowering the effect of high resolution printing. Achieve improvement. FIG. 22 shows the dot arrangement by double-strike printing in this embodiment. In this example, a dot with a large ink droplet is overlaid with a dot with a large ink droplet again, and a dot with a large ink droplet used for low-resolution recording is overlaid on a dot with a small ink droplet used for high-resolution recording. Is recorded by superimposing dots on the grid points (360 dpi) for low resolution recording.

When a plurality of small dots are arranged again with high density on the image recorded with high density, the amount of ink on the image area increases, and the edge of the image may be crushed due to bleeding or runoff. In order to prevent such a problem, as shown in FIG. 22, a large ink droplet is formed on a low resolution grid point different from the grid point for high resolution recording so that the small dot d9 is not exposed to the second ink drop. It is arranged. With this configuration, it is possible to improve the density of an image without causing deterioration of an image edge portion caused by an excessive amount of ejected ink. Further, it is not necessary that the areas where the dots are overlapped and the dots are overlapped are in the entire area, and for example, the large dots may be overlapped only in the small dot portion.

(Other Examples) In each of the above examples, the present invention has been described by taking the ink jet recording apparatus shown in FIG. 7 as an example. The inkjet recording apparatus shown in FIG.
As described above, a piezo element which is an electromechanical conversion means is used as the means for ejecting ink.

The present invention is not limited to the above-mentioned recording apparatus and can be widely applied.

FIG. 1 is another example to which the present invention can be applied, and shows a perspective view of an ink jet recording apparatus of a type in which ink is ejected by an electric / heat converting means. Recording device 10
The recording medium 106 inserted in the 0 sheet feeding position 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. The 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). 10
A switch and a display panel 7 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.

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 amount of each color ink droplet ejected is about 4
It is 0 ng.

On the other hand, during high-resolution recording, only H1 of each nozzle is controlled to generate heat, and the amount of ink droplets of each color ejected is about 20n, which is smaller than during low-resolution recording.
g.

As described above, by using the recording head capable of ejecting different volumes from the same nozzle, high resolution recording was performed 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.

Further, the amount of ink droplets to be ejected is not limited to the above-mentioned example, and it is possible to eject ink droplets having a larger volume or a smaller volume depending on the ejection conditions and the head.
Any of these can be applied to 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, the recording head using the electrothermal converter uses the bubbles formed by the application of thermal energy at the time of ejecting ink droplets, and is therefore commonly called a bubble jet recording head.

The present invention is particularly effective in a recording apparatus using an inkjet recording head for recording by forming flying liquids by utilizing thermal energy among the inkjet recording systems.

Regarding the typical structure and principle thereof, see, for example, US Pat. Nos. 4,723,129 and 4740.
What is done using the basic principles disclosed in 796 is preferred. This method 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, other than the combination constitution (straight liquid flow passage or right-angled liquid flow passage) of the discharge port, the liquid passage, and the electrothermal converter as disclosed in the above-mentioned respective 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.

Further, the present invention can be effectively applied to a full line type recording head having a length corresponding to the maximum width of a recording medium which can be recorded by the recording apparatus. Such a recording head may have a configuration that satisfies the length by a combination of a plurality of recording heads or a configuration as one recording head integrally formed.

In addition, even in the case of the serial type as in the above example, the recording head fixed to the apparatus main body, or the electrical connection with the apparatus main body or the ink from the apparatus main body by being attached to 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 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 a form of the ink jet recording apparatus of the present invention, other than the one used as an image output terminal of an information processing apparatus 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.

[0086]

As described above, by using an ink droplet diameter (dot diameter) different from that of a low resolution (= ink ejection port pitch in the print head) printing mode, a high resolution high density printing mode can be obtained. A high-speed printing mode with low resolution has been realized to speed up image recording. Also, by using large dots instead of small dots, the number of times the print head is driven can be reduced and the number of recordable recording media can be increased. (Longer life of recording device)

Further, in a dot arrangement in which different resolutions (large and small dots) are mixed, the positional relationship between the large dots and the small dots is moved to the main scanning or the sub scanning or both in units of ¼ of the ink ejection port pitch. This makes it possible to eliminate image shifts due to differences in resolution.

Further, by utilizing the fact that the grid points of the dot arrangement are different when the resolution is different, it is possible to improve the image density while taking advantage of the high density recording.

In the above-described embodiment, the scan for ejecting a large ink droplet to form an image and the scan for ejecting a small ink droplet to form an image are divided into a low-resolution recorded image and a high-resolution recorded image. And are mixed. Since the scanning is divided into a plurality of scans, stable ink ejection can be performed with almost no disturbance of ink inflow that occurs when ink droplets of different ejection amounts are ejected at the same time.

In the description in the text, the low resolution is 360 dp.
i, the high resolution is set to 720 dpi, but the present invention is not limited to this, and the effects of the present invention are effective even if a combination of 300 and 600 dpi and 400 and 800 dpi is used. The size ratio of the ink droplets or the ejection amount itself is also effective other than the values in the text. Although bidirectional printing was described as the printing method, this case is also effective for printing scanning in only one direction.
Further, the printing mode switching depending on the kind of the recorded image is described as the high density printing of the black image, but the color image may be recorded at the high density depending on the purpose of image output. That is, the judgment criteria vary depending on the purpose, but the effect itself of the present invention is effective.

The recording method of the present invention can also be applied to improve gradation reproducibility by multi-value recording. Alternatively, the same effect can be expected by using large and small dots properly for a dark and light ink recording method using inks of different densities.

[Brief description of drawings]

FIG. 1 is a perspective view of an inkjet 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 showing an arrangement of heaters that are ejection means of the recording head.

FIG. 5 is a diagram showing details of a recording head using a piezo element as an ejection unit.

6A is a diagram showing a configuration in which a black head is shifted by half a pixel, and FIG. 6B is a diagram showing a conventional print head.

FIG. 7 is a diagram showing an inkjet recording apparatus applied to the present invention.

FIG. 8 is a dot arrangement showing high speed (low resolution recording).

FIG. 9 is a dot arrangement showing high-density recording in the main scanning direction.

FIG. 10 is a dot arrangement showing high density (high resolution recording).

FIG. 11 is a dot arrangement showing long-life printing.

FIG. 12 is a diagram showing measures for preventing dot deviation when different resolution data are mixed.

FIG. 13 is a diagram showing measures for preventing dot deviation when different resolution data are mixed.

FIG. 14 is a diagram showing 1-pass bidirectional printing.

FIG. 15 is a diagram showing 2-pass bidirectional printing (high-density recording only in the main scanning direction).

FIG. 16 is a diagram showing a printing method in which high density recording is performed in both main scanning and sub scanning.

FIG. 17 is a diagram showing a combination of recorded image types.

FIG. 18 is a diagram illustrating a multi-pass printing method.

FIG. 19 is a diagram illustrating a multi-pass printing method.

FIG. 20 is a diagram illustrating a multi-pass printing method.

FIG. 21 is a diagram illustrating a multi-pass printing method.

FIG. 22 is a diagram showing a dot arrangement in a double-strike mode in which dots of different sizes are used.

FIG. 23 is a functional block diagram illustrating an apparatus of the present invention.

FIG. 24 is a functional block diagram illustrating an apparatus of the present invention.

[Explanation of symbols]

 1 Print Head 2 Paper Ejection Roller 4 Carriage Shaft 400 Print Head Recovery Device 420 Protection Cap

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical indication location H04N 1/23 101 B 1/52 H04N 1/46 B (72) Inventor Hiroshi Taka Ota-ku, Tokyo Shimomaruko 3-30 2 Canon Inc. (72) Inventor Norifumi Koitabashi 3-30-2 Shimomaruko Ota-ku, Tokyo Canon Inc. (72) Inventor Fumihiro Goto 3 Shimomaruko Ota-ku, Tokyo No. 30-2 Canon Inc.

Claims (20)

[Claims] 1. An ink jet recording apparatus comprising an ejection unit for ejecting ink and forming an image on a recording medium, and an ejection amount control unit for controlling the amount of ink droplets ejected from the ejection unit, An inkjet recording apparatus, comprising: a recording control unit that changes the amount of ink droplets ejected by the ejection amount control unit according to the type to form an image. 2. The ink jet recording apparatus according to claim 1, wherein the recording control unit determines whether or not the recorded image is a character and changes the amount of ink droplets ejected to form the image. Recording device. 3. The recording control means determines whether the recorded image is a black image or a color image and changes the amount of ink droplets ejected to form the image. 1. The inkjet recording device according to 1. 4. The recording control means determines whether the data of the recorded image is image data of relatively low resolution or image data of high resolution, and changes the amount of ink droplets ejected. The inkjet recording apparatus according to claim 1, wherein an image is formed by using the image forming apparatus. 5. The recording control means changes the amount of ink droplets ejected to form an image depending on whether or not the data of the recorded image includes high resolution data that can be converted into low resolution. The inkjet recording device according to claim 1, wherein 6. The inkjet recording apparatus according to claim 1, wherein the recording control unit forms an image by changing the amount of the ejected ink droplets in recording in page units. 7. The ink jet recording apparatus according to claim 1, wherein the recording control unit changes the amount of the ejected ink droplets when recording changes the type of image to form an image. 8. A printing mode setting means is provided, and the recording control means changes the amount of the ejected ink droplets according to the printing mode to form an image. The inkjet recording device according to item 1. 9. An ink jet recording method for forming an image by ejecting ink onto a recording medium by an ejecting means for ejecting ink, a determining step of determining a type of a recorded image, and the ink ejecting according to the determining step. And a recording step of forming an image by changing the amount of ink droplets ejected by the means. 10. The inkjet recording method according to claim 9, wherein the determining step determines whether or not the recorded image is a character. 11. The inkjet recording method according to claim 9, wherein the determining step determines whether the recorded image is a black image or a color image. 12. The inkjet according to claim 9, wherein the determining step determines whether the data of the recorded image is image data of relatively low resolution or image data of high resolution. Recording method. 13. The ink jet recording method according to claim 1, wherein the determining step determines whether or not the data of the recorded image includes high resolution data that can be converted into low resolution. 14. An inkjet recording apparatus having recording control means corresponding to at least two kinds of recording densities of high resolution and low resolution and capable of ejecting ink droplets of different sizes corresponding to respective resolutions. An ink jet recording apparatus comprising: a control unit capable of ejecting ink droplets of different sizes onto a recording medium with a recording density N (N is an integer of 2 or more) times the recording density. 15. An ink jet recording apparatus having a recording control means corresponding to at least two kinds of recording densities of high resolution and low resolution and capable of ejecting ink droplets of different sizes corresponding to respective resolutions, An inkjet recording apparatus comprising: a control unit that performs recording scanning separately for each recording of different resolutions. 16. An ink jet recording apparatus, which comprises an ejecting unit for ejecting ink and ejects ink onto a recording medium to form an image, an ejection amount control unit for controlling the amount of ink droplets ejected from the ejecting unit. And an overlap printing control unit that arranges the ink droplets at the same position of the recording medium so as to be divided into a plurality of times so as to be overlapped with each other, and the overlap printing control unit, in a plurality of recording scans,
An ink jet recording apparatus, characterized in that the ejection amount control means divides ink droplets having different ejection amounts into a plurality of times and superimposes them on an image. 17. In an ink jet recording apparatus, which comprises an ejecting unit for ejecting ink and ejects ink on a recording medium to form an image, a recording control unit capable of recording at a plurality of different pixel densities and the same recording medium. And an overlap printing control means for arranging the ink droplets at a position so as to be overlapped a plurality of times, wherein the overlap printing control means is an ink droplet recorded at a different pixel density at the same position on the recording medium. An ink jet recording apparatus, characterized in that a plurality of times of scanning is performed to perform overprinting. 18. An ink jet recording apparatus having recording control means capable of recording at least two kinds of recording densities of high resolution and low resolution, and capable of forming ink droplets of different sizes corresponding to respective resolutions on a recording medium. 2. An ink jet recording apparatus according to, wherein the dot rows arranged in a row in the horizontal and vertical directions have control means for forming a low resolution image by ink droplets of a relatively large size. 19. The ink jet recording apparatus according to claim 18, wherein the control unit forms a high resolution image by ink droplets having relatively small dots other than the low resolution image. 20. An ink jet recording apparatus having recording control means capable of recording with at least two kinds of recording densities of high resolution and low resolution and capable of forming ink droplets of different sizes corresponding to respective resolutions on a recording medium. 2. In the inkjet recording apparatus, a plurality of relatively small ink droplets are arranged in one pixel of dots formed at low resolution when forming a high resolution image.