JP3271731B2 - 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. Method and recording method, such as ordinary paper, special paper, cloth, O
The present invention can be applied to all devices that use a recording medium such as HP paper, and specific devices include a printer, a copying machine, a facsimile, and the like.

[0002]

2. Description of the Related Art In recent years, OA devices such as personal computers and word processors have become widespread. As a method for outputting information input by these devices on 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 have been put to practical use. In these recording methods, a predetermined image is formed on a recording sheet conveyed by a print head of each method, and there is a remarkable difference between the respective print heads. Among them, the ink jet recording method is a recording method that has recently attracted attention as being effective for high image quality and high resolution because of low noise due to non-contact with a recording medium.

A print head in an ink jet recording system includes a sheet holding ink,
There is a configuration in which an electric / heat converter is arranged corresponding to a liquid path (nozzle) of ink. In this configuration, by applying a drive signal corresponding to the recording information to the electric-to-heat converter, heat energy is generated in the electric-to-heat converter which causes a rapid temperature rise exceeding the nucleate boiling in the adjacent ink. Let
Film boiling occurs on the heat acting surface in the nozzle of the print head, and as a result, a bubble is formed in the ink in the nozzle corresponding to the drive signal. If this start signal is formed into a pulse shape, the formation and shrinkage of air bubbles are performed immediately and appropriately, so that ink ejection with particularly excellent responsiveness can be achieved.

As another configuration of the ink jet recording system, an electro-mechanical converter (referred to as a heater) is provided in the ink flow path or around the ink liquid path, and the electro-mechanical converter corresponds to the recording information. By applying voltage, electricity and
A method of forming an image by causing ink droplets to fly by 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 the discharge energy.

As an invention for providing a high-definition image by the ink jet recording method, Japanese Patent Publication No. 54-41329 discloses a method of recording images (characters) having different dot pitches (resolutions) using dots of different sizes. Is disclosed.

[0006]

In the conventional ink jet recording method and recording method suitable for high-resolution recording or high-gradation recording, the conventional method involves changing the resolution or changing the image type (dot size in this case). Nothing has been considered about the situation.

The inventors of the present invention have examined the case of such a resolution conversion and the case of a change in image type, and have found a new problem. That is, when the recording area of a relatively high resolution and the recording area of a low resolution are close to each other due to the change of the dot size, which is a change of a different resolution, or the image itself that should have been changed to the high resolution is an ink image. This is a problem that an image omission area or a density enhancement area is partially generated.

A specific example will be given here. In general, as the resolution increases for higher image quality, the unit pixels forming the image become smaller, so it is necessary to reduce the diameter of the print dots forming the unit pixels. This is different from the electrophotography system and the system using solid ink. In the ink jet system using liquid ink, image deterioration due to ink overflow on the recording medium and deformation of the recording medium itself (reduction of waving called cockling) are prevented. It is necessary to Also,
In order to record the same area of the recording area by printing dots, many dots are required. For example, 360dp
When recording at a resolution of i (dotsper inches), 360 × 360 (dpi) per square inch
In the case of performing high-resolution recording while printing dots, for example, 720 × 360 (dpi), 720 × 720
In the case of recording at a density of (dpi), the number of dots per unit area becomes two to four times.

When dots having different resolutions are arranged, the grid points (center points of the dot arrangement) at the respective resolutions are shifted, so that the dot arrangement is shifted. This situation is shown in FIG. As can be seen from FIG. 10, a substantial image missing area of the ink image is generated as a gap (A) due to the dot shift at the boundary between the areas where the large and small dots are arranged. In the gap A, the printing mode is changed because the resolution and size of the dots to be printed have changed. In the figure, white portions in the cells appear as white stripes.

FIG. 11 shows an example in which different types of images (here, large dots and small dots) are mixed in the same raster. It can be seen that a gap B is generated at the junction between the large dot and the small dot shown in FIG. In addition, it can be seen that the density emphasis area C is partially generated although it is very partial.

As described above, when the print mode is changed according to the type of the recorded image such as the resolution, there is a disadvantage that the uniformity of the recorded image is disturbed.

Further, as a problem associated with the change of different resolutions, especially in the case of high-resolution printing, ink droplets of the same size are used in the double-strike mode in which the same dot is printed twice at the same position as a print density improving measure. Is recorded at the same position, density improvement can be achieved, but image degradation may occur rather than emphasizing low resolution portions due to ink bleeding.

[0013]

According to the ink jet recording method of the present invention, dots are formed by using an ink jet head for discharging ink and discharging ink from the ink jet head onto grid points corresponding to the resolution. In an inkjet recording method for recording an image on a recording medium, a grid point for recording a low-resolution image is positioned on a lattice point for recording a high-resolution image with reference to a lattice point corresponding to the low-resolution image. And the high resolution
The size of dots formed when recording an image is
This is the size of the dots that are formed when printing a resolution image.
In addition to performing recording with a relatively small size , when recording an image on a recording medium, a low resolution
When changing the resolution from a high-resolution image to a high-resolution image,
Images where images with different resolutions occur in adjacent areas
In the white area , recording is performed by supplementing dots .

In the above-described white area, recording is performed by supplementing dots on grid points corresponding to the high-resolution image, but when the image is recorded on a recording medium, the resolution is changed.
Accordingly, when the resolution is changed from a high-resolution image to a low-resolution image, printing is performed by thinning out dots to be formed in adjacent regions where images having different resolutions are adjacent to each other.

In the recording of the high resolution image,
The data corresponding to the dots to be formed is the low-resolution image.
Based on the data corresponding to the dots forming in the image recording
It is those that are generated Zui, control of formation of the dots
Is used to convert low-resolution data to high-resolution data.
The arrangement of the dots when converting to data
To change or record the high resolution image
The data corresponding to the dots to be formed
Data corresponding to the dots forming in the recording of the image
Is generated on the basis of
Controls data corresponding to low resolution to high resolution.
Dot when converting to data and performing density enhancement recording
Change the arrangement according to the data, and add and delete parts.
And further records the high-resolution image.
The size of the dots to be formed when
Relatively larger than the size of the dots formed when recording the image
This is to make the recording smaller.

The ink jet recording apparatus of the present invention records an image on a recording medium by using an ink jet head for discharging ink and discharging ink from the ink jet head onto grid points corresponding to the resolution to form dots. In an ink jet recording apparatus, means for recording a grid point when recording a low-resolution image as a grid point when recording a high-resolution image, with reference to a lattice point corresponding to a low-resolution image. , To the resolution
Accordingly, a dot formed when recording the high-resolution image is formed.
The size of the cutout when recording the low resolution image.
Record relatively small than the size of the dot to be formed.
As shown in FIG.
And a control means for changing the amount of click droplets, in accordance with the change of resolution when recording an image on the recording medium, means for determining a neighboring region where images with different resolutions are adjacent, the adjacent region
Based on the result of the judgment of
When changing the resolution to an image, images with different resolutions
The white area of the image generated in the adjacent area that touches
Means for supplementing the data and recording .

Also, it is determined whether or not the image to be recorded is a character.
Further comprising means for performing the
Record as the high resolution image, or
Indicates whether the image to be recorded is a black image or a color image
Means for determining whether the image to be recorded is black.
Depending on whether the image is an image or the color image,
The resolution is changed, and the
The jet head applies thermal energy to the ink
This is to discharge ink.

According to the present invention, recording is performed by changing the resolution.
Possible inkjet recording method and inkjet
In the recording device, grid points corresponding to low-resolution images
As a criterion, grid points for recording low-resolution images are
High resolution on grid points when recording high resolution images
In the configuration that records images with low resolution and high resolution,
Due to the change, images with different resolutions may be
Cause image omission and areas where the density is emphasized.
The problem is that the formation of dots in the boundary area
Achieve improved recording quality by controlling the control
be able to.

[0019]

【Example】

(First Embodiment) FIG. 18 shows an example of a serial type ink jet color printer to which the present invention is applied.

The print head 1 is a device having a plurality of nozzle rows and performing 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. 17B is a diagram showing the configuration of a print head row and an ink tank 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, in the order of C and Y,
When forming a blue (hereinafter B) image, ink droplets are respectively landed in the order of C and M to form a color image.

The carriage 201 receives power from the carriage drive motor 8 and is transmitted by the belts 6 and 7 to move on a 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 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 and 10K mounted on the carriage 201.
C, 10M, and 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. 16 shows details of the recording head shown in FIG. As a configuration of a recording head, for example,
A recording head having a configuration using an electromechanical transducer as shown in JP-A-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.

FIG. 30 is a functional block diagram of the recording apparatus in this embodiment. The recording apparatus that has received the recording data and the printing mode data determines which recording mode to use by the recording mode determining means. The criterion for determining the recording mode is based on the type of the recorded image and the like. For example: 1. whether or not the recorded data is characters; 2. Whether the recorded data is a black image or a color image 3. Low or high resolution? The recording mode can be determined based on which recording medium is selected, and the like. If the high-density printing mode, which is the second recording mode, is selected, the conditions of the print head to be driven (the driving conditions for discharging small dots in this case) and the like are set by the “second droplet discharge setting”. Is done. In the next “high-resolution processing”, processing such as converting data provided corresponding to a normal print density into print data corresponding to high-resolution printing is performed. In the subsequent “data partial processing”, a process of generating small dot data at a position that did not exist in the low-resolution data is performed. In the "second recording condition setting" section, detailed print mode conditions are determined. That is, the information includes the transport amount of the recording medium, the moving speed of the carriage, the number of print passes, and the like. The “recording apparatus control system” receives these pieces of information, and actually controls the driving of the print head and the driving of the recording medium transport motor and the like. These controls are performed to develop data for several lines or pages of the print head, and to switch the recording mode for each carriage scan because the main body has information for several scans in advance. It has become. Further, the above-described recording mode determination criteria can be changed according to the purpose of image output. For example, high resolution recording is not always performed for a character or a black image. Other than the image, the high-resolution recording mode may be set.

A part or all of the processing up to the recording apparatus control system in the above series of processing is performed by a device capable of transmitting and receiving data to and from the recording device without performing the recording device main body, such as a host computer. It may be processed.

<Multi-pass printing method (fine printing method)> In printing an image image, various factors such as coloring, gradation, and uniformity are required. In particular, regarding uniformity, slight variations in the nozzle unit that occur during the print head manufacturing process affect the ejection amount and ejection direction of each nozzle when printing, and eventually result in uneven density of the printed image. This may cause deterioration of image quality.

An example of the occurrence of density unevenness will be described with reference to FIGS. 26 and 27 using a monochromatic print head as an example for simplification.
FIG. 26 shows an example of printing by a recording head in which characteristics such as the ejection amount and the ejection direction are uniform without variation in nozzle units.
In FIG. 26A, reference numeral 91 denotes a print head, which is composed of eight nozzles for simplification. 9
Numeral 3 denotes an ink droplet ejected by the multi-nozzle 92. Ideally, the ink is ejected in a constant direction at a constant amount as shown in FIG. If such ejection is performed, dots of uniform size are landed on the paper as shown in FIG. FIG.
(C) shows the relative density of the recorded image of each recording dot. As is clear from the drawing, a uniform image without density unevenness is obtained as a whole.

However, in practice, as described above, there is a variation in each of the nozzles, and if printing is performed in the same manner as described above, as shown in FIG. The size and direction of the ink drops ejected from the respective nozzles vary, and land on the paper surface as shown in FIG. 27B. FIG.
In (b), white lines (unprinted) are generated in a portion of white paper (unprinted) where the ink is not landed and the area factor cannot be 100% in the main scanning direction due to a variation in the ejection characteristics of the print head. On the other hand, this indicates that dots are overlapped more than necessary and black stripes are generated in a portion where the print density is high. The collection of dots landed in such a state is shown in FIG.
As a result, these phenomena are perceived as density unevenness as far as the human eye normally sees. In addition, 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 to complete the print area shown in FIG. 26 and FIG. 27, and the area of a 4-pixel unit which is half the print width of the print head is It is completed in two consecutive passes. In this case, the eight nozzles of the print head are divided into two groups: upper four nozzles and lower four nozzles. The dots printed by one nozzle in one scan are defined image data according to a predetermined arrangement. It has been thinned out by about half. Then, after the paper is fed at the time of the second scan, dots are embedded in the remaining image data not recorded by the first scan by using a nozzle different from that of the first scan, and complementary recording is performed. Complete printing in pixel unit area. The above recording method is called a fine recording method. When this recording method is used, an image is formed by a plurality of nozzles in the same recording area even if a head having a variation in ejection characteristics is used similarly to the print head shown in FIG. Since the influence on the image is reduced, the printed image is as shown in FIG. 28 (b), and the black streak and the white streak as shown in FIG. 27 (b) become inconspicuous. Accordingly, as shown in FIG. 28C, the density unevenness seen on the recorded image is considerably reduced as compared with the example of FIG.

When performing the fine recording as described above, the first scan and the second scan divide the image data in such a manner as to complement each other in accordance with a predetermined arrangement so as to complement each other. Figure 2)
As shown in FIG. 9, it is most common to use a staggered grid for each pixel in the vertical and horizontal directions. Therefore, in the unit print area (here, in units of four pixels), printing is completed by the first scan for printing the staggered grid and the second scan for printing the inverted staggered grid. FIG. 29 (a), 2
9 (b) and 29 (c) show how a recording in a certain area is completed when the staggered and inverted staggered patterns are used, as in FIGS. 26 and 27, respectively. This is explained using FIG. 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. 29B, the paper is fed by four pixels (１ ／ of the total nozzle width), and the inverted zigzag pattern is printed. Further, at the third scan, as shown in FIG. 29C, the paper is fed again by four pixels (１ ／ of the total nozzle width) again, and the staggered pattern is recorded again. In this manner, by sequentially performing paper feed in units of four pixels and recording in a zigzag or inverted zigzag pattern, a recording region in units of four pixels is completed for each scan. As described above, by printing in the same area using two different types of nozzles, it is possible to obtain a high-quality image with reduced density unevenness. Also, various mask patterns for thinning other than staggered and inverted staggered may be used according to the purpose. Also, instead of completing the recording of the recording area by two scans,
For example, printing may be performed using a complementary pattern by three or four scans.

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

Image formation in this embodiment is mainly performed by switching between two print modes. One is a high-speed printing mode in which printing is performed at a normal pixel density (referred to as high-speed printing because printing can be performed at a higher speed than in high-density recording).
The other is a high-density printing mode for printing at high resolution. In addition, the high-speed printing mode has a lower resolution than the high-resolution mode, and is therefore also referred to as a low-resolution mode.

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

In the high-speed printing mode of this embodiment, printing is performed during a single scan by using all the discharge nozzles of the print head (hereinafter, one-pass printing). FIG. 22 shows an example of one-pass bidirectional printing, in which the print head has 16 discharge ports. The high-speed print mode of this example is defined as a mode for printing a low-resolution image, and the print dots in FIG. 22 have a print density of 360 dpi in both the 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 low resolution. Since the recording density is low, the ink droplet diameter per unit pixel is preferably larger than that of high-resolution printing. In this embodiment, the ratio of the ink droplet volume to be ejected is set differently depending on the characteristics of the ink. Ink droplets) is approximately 2: 1. In this example, the ejection amount of the large ink droplet is about 80 pl, and the ejection amount of the small ink droplet is about 40 pl. FIG. 19 shows the dot arrangement of the low-resolution image recorded by the one-pass printing described above in detail. The horizontal direction in the figure is the main scanning direction in which the carriage moves, and the vertical direction is the sub-scanning direction in which the recording medium transport direction and the ink discharge ports are arranged. The intersection of the vertical and horizontal lines indicated by the dotted lines in this figure is the grid point at a recording density of 360 dpi. In the printing example of FIG. 19, an image is formed by arranging dots indicated by d1 only at grid points of 360 dpi.
The number of dots constituting the image shown in FIG. 19 is 40 for large ink droplets.

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

FIG. 20 shows an example in which recording is performed at 720 dpi, which is twice the image density in the main scanning direction, with respect to the recording image of FIG. In this printing method, the original image is 360
Even at a resolution of dpi, pseudo high-resolution printing is achieved by adding or reducing printing dots in the main scanning direction. In the example shown in FIG. 20, two dots are arranged in one pixel having a pixel density of 360 dpi in the main scanning direction. Also in FIG. 20, the intersection of the vertical and horizontal lines indicated by the dotted lines is 360 dpi.
Grid points. In FIG. 20, the dot (d
2) are recording dots arranged on the grid points,
The dots painted in gray indicated by d3 are the recording dots that are arranged shifted from the lattice points by 720 dpi.

The number of recording dots for forming the image shown in FIG. 20 is 80, which is twice that of the image shown in FIG. As shown in FIG. 20, as a specific printing method for performing high-density printing in the main scanning direction, the frequency of ink ejection is the same as in the normal printing mode, and the moving 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 from the positions of the printing dots by the first scan by half a pixel in the main scanning direction. High-density recording can also be achieved by recording at a position. FIG. 23 shows a method for increasing the recording density in the main scanning direction by the latter method. A dot (d2) in FIG. 20 is a recording dot arranged at a grid point of 360 dpi, and performs recording in the forward scan (scanning from left to right in the drawing and printing) shown in FIG. The dot d3 shown in FIG. 20 is a recording dot which is arranged at a position shifted by half a pixel of 360 dpi from the recording position of the dot d2, and performs recording by backward scanning (printing from right to left in the drawing). Since the recording density in each scan of the reciprocating scanning is 360 dpi, and the normal low-resolution printing is maintained, the carriage moving speed and the ink ejection frequency may be the low-resolution printing. As a result, since the print area is divided into a plurality of times and recorded, the image recording time for the same area is later than the high-speed print mode by the number of divisions, but as described in the multi-pass printing described above, raster printing using different nozzles is performed. Since an 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 embodiment, the above-mentioned two print modes are switched depending on whether the image type is character data or not. Usually, character data contains a common control code, so by detecting this information, it is possible to determine whether or not a character exists in the image data. This detection unit may be performed by a host computer (CPU) that handles image data, or the recording unit may include the detection unit. Since the character data has continuous oblique lines and curved portions, high image quality can be realized using the high-density print mode described above. Since it is assumed that there are many relatively isolated dots for images other than character data, a high-speed print mode (low-resolution recording) is performed.

The functional block diagram shown in FIG.
At step 1, the input data is determined. The determination of the data may be performed on the recording device side as described above, or the configuration may be such that the determination is performed on the host side.

As described above, by switching the print mode according to the image data, it is possible to realize a recording suitable for the image data and to shorten the recording time. That is, high-quality recording is performed only in an image requiring high-density recording in a print mode with a low recording speed, and the recording time can be reduced in a high-speed print mode for an image having a low recording density and little problem.

The following is an example in which the volume ratio between the ink ejection amount ejected during low-resolution printing and the ejection amount ejected during high-resolution printing is made different.

Here, the ratio of the volume of the ink droplet to be ejected is determined by a dot (large ink droplet) ejected for low-resolution printing and a relatively small dot (small ink droplet) ejected for high-resolution printing. , Approximately 4: 1. 360 dpi
Assuming that approximately 80 pl of ink droplets are arranged in one pixel formed by 360 dpi, the ejection amount of large ink droplets is about 80 pl, and the ejection amount of small ink droplets is about 20 pl.

FIG. 21 shows the dot arrangement in the high-density printing mode. Since the ejection amount ratio of dots of different sizes is 4: 1, instead of forming one dot with a large ink droplet in one pixel of 360 × 360 dpi, four small ink droplets are used.
Will be arranged. The intersection of the vertical and horizontal dotted lines is 360
It is a grid point of dpi. Therefore, the dots arranged on the vertical and horizontal lines indicated by the solid lines are half pixels (720 dpi) of 360 dpi.
This indicates that the image was recorded at a position shifted by one pixel (dpi). The dot d4 painted in gray has a density of 720 dpi in the main scanning direction and 360 d in the sub-scanning direction.
It is recorded in units of pi. The dot d5 indicated by oblique lines is equivalent to the dot d4 which is 360 dp in the sub-scanning direction.
This is a dot recorded at a position shifted by a half pixel of the pixel i. In this embodiment, printing is performed by arranging 176 dots by small ink droplets.

When the high-resolution recording image shown in FIG. 21 is obtained, the input recording data corresponds to the low-resolution image as shown in FIG. It is necessary to create
Hereinafter, a procedure for obtaining image data for recording a high-resolution image shown in FIG. 21 from the low-resolution image data of FIG. 19 will be described.

First, the original image data shown in FIG. 19 is divided into "original image data", "right of original image data", "below original image data", and "lower right of original image data". And data corresponding to a recording position of 4 times the original image at twice the resolution in each of the vertical and horizontal directions at the four positions. Subsequently, based on the created data, if the corner is a two-dot corner where the edge part is continuous in both the vertical and horizontal directions, data of one dot in a high-resolution recording unit is added to the corner. However, if the edge is in either the horizontal or vertical direction,
If there is a continuous dot or more, there is no data to be added.

With the above processing, the image data of FIG. 21 is obtained from the image data of FIG. This method is also applied as an example of the smoothing process, and another method other than this method may be applied to the smoothing process itself.

The recording method of this embodiment will be described with reference to FIG. In the present embodiment, since printing is performed at a pixel density of 720 dpi also in the sub-scanning direction (recording paper transport direction), a paper feeding operation shifted by a half pixel of 360 dpi in which nozzles are arranged is required. In this drawing, the description will be made on the assumption that the number of ink ejection ports in one head is 16. First, when recording is performed by scanning the recording head from left to right in the drawing (forward scanning), printing is performed at a pixel density of 360 dpi in the sub-scanning direction. In FIG. 24, it is indicated by a gray circle. Next, when recording while 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 in the forward scanning. That is, by setting the conveyance amount L of the recording medium to 7.5 nozzles, it becomes possible to record the dot d5 indicated by the oblique line in FIG. In FIG. 24, they are indicated by white circles for easy viewing. Subsequently, the recording medium is transported by the transport amount L '(for 8.5 nozzles), and printing is performed at a density of 360 dpi in the sub-scanning direction. By repeating these operations, a reciprocating scan is carried out for 16 nozzles, which is the entire discharge port width. 360dp like this
By using the conveyance of the printing medium shifted by half a pixel of i and the multi-pass printing method, high-density printing of 720 dpi can be performed in both the main scanning direction and the sub-scanning direction.

In the present embodiment, the type of recording image serving as a reference for switching the recording mode is switched depending on, for example, a color image or a black image. Normally, a higher density recording of a black image has a higher effect of improving the printing result than color data. This is because black is conspicuous in the recorded image, and many images that require the reproducibility of curves such as characters as black images are cited. 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 determination function may be provided in the main body of the recording apparatus. The above-described switching of the recording mode may be performed by determining whether or not there is data for driving the black head.

The switching of the printing mode is performed within a page in this embodiment. If the print mode is switched in the page, the rows requiring high-density recording (black image in this embodiment) are recorded at a high density of 720 dpi, and when the recorded image changes to a color image, a low level as shown in FIG. Print in high-speed print mode with resolution. In the case of color recording, the amount of ink may be smaller than that of black ink droplets because color mixing such as secondary colors occurs. As an example, when the ejection volume ratio of ink droplets of different sizes of color ink (CMY) is 4: 1, the ejection volume ratio is 40 (pl): 10 (pl).

FIG. 25 shows an example of an image arrangement based on print data assuming that the print mode is switched within a page. The image example shown in FIG. 25 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 areas indicated by A, D, E, and G in FIG. 25 are printed in the high-density print mode because the black image exists. When there is no black data in other image areas, FIG.
The printing is performed in the low-resolution high-speed printing mode shown in FIG. However, in this example, the black image in the color image is a black image because black is prioritized. In addition, 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. 25 is in the high-density recording mode, and in other areas, the printing mode changes depending on the presence or absence of black data.

In the above example, the printing mode may be switched according to the type of the recorded image for each resolution. For example, the resolution may be switched depending on whether the resolution of the recorded image is higher or lower than the resolution of the print head, or a threshold value (360 dpi, 300 dpi, etc.) may be set and the resolution of the image data may be higher. You can switch between low and high.

Referring to FIG. 1, prevention of image deterioration in a print mode change portion using the recording apparatus described above will be described. Note that the recording head of this example is an example in which dots with different ink droplet diameters can be ejected within the same head (same nozzle, ejection port). The large dot group in the square is a case where recording is performed at the resolution or the dot diameter as in the above-described high-speed recording mode, and the small dot group is recording in the high-density recording mode.

As can be seen from the comparison between FIGS. 1 and 10, the printing mode changing unit A shown in FIG. 1 shows that the grid points of the dot arrangement are displaced between the printing modes and that the dot size in this example is different. The dots da indicated by the gray circles are arranged so that no gaps where the dots are not arranged due to the difference are generated,
The white stripes generated in FIG. 10 are erased. The printing method in FIGS. 10 and 1 has been described in the multi-pass printing method described above. That is, for recording in the raster direction, density unevenness or the like due to a print head or the like is removed using different ink ejection ports. In the figure, it can be seen that image formation is performed using two ink ejection ports in the raster direction (main scanning direction). In FIGS. 10 and 1, since the above-described half-pixel feed is performed, the recording medium conveyance amount alternately repeats 1.5 nozzles = a and 2. nozzles = b. FIG. 1 shows an example in which all the dot arrangements in the print mode change portion (boundary portion) are painted out, but the present invention is not limited to this.

FIG. 3 shows an ink image to be replenished in the boundary area A. As shown in FIGS. 3 (a) and 3 (b), the dot arrangement in the boundary area should be thinned out. This shows a preferable case, and a dot da indicated by light gray in the figure is an additional dot row. As a specific example, a recording medium having a small ink receiving amount (OHP sheet or the like)
In some cases, it may be more appropriate to fill the gap a little. Also, as shown in FIG. 3C, a correction dot may be arranged on the left side of FIG. 3 to correct the deviation of the recording start position in the main scanning direction after the print mode is changed. FIG.
(D) to (f) show the dot arrangement when the print mode is changed from the small dot arrangement to the large dot arrangement.
Here, since the grid points of the dot arrangement are displaced in such a manner that the small dot area penetrates the large dot area, the dot dc row which is the recording data is thinned out and deleted.

FIG. 2 shows a recording method when the conveyance amount of the recording medium is fixed. The recorded image is the same as FIG. Since the multi-pass printing method is performed with the recording medium conveyance amount a = 1.5 nozzles, in this example, two out of eight nozzles of all the print head nozzles are not used. The white circles in FIG. 2 are the unused ink ejection port arrays.
Since the recording medium conveyance amount is made constant by recording according to this method, the design of the conveyance system is facilitated.

As described above, by arranging or deleting recording dots in the print mode changing section or changing the feed pitch of the recording medium, image deterioration of the changing section can be prevented.

(Second Embodiment) This embodiment shows a method of preventing image deterioration when different types of recorded images are mixed in the same raster. In FIG. 4A, the low-resolution grid (360
(dpi) Grid points are indicated by intersections of vertical and horizontal lines in broken lines, and the vertical and horizontal directions of 360 × 360 dpi represent nine pixels. The target pixel d (the central pixel indicated by the asterisk) is recording in the high-density recording mode, and is an example in which one large dot is converted into four small dots. That is, dots d 'indicated by small white circles are arranged at three places, right, lower right, and right below the dot d. Also, the dot dx in FIG.
Are low-resolution data (large dots) arranged on the above-described low-resolution grid. In this figure, a total of five are arranged above and to the left of the target pixel d (three large white circles have no image data) It is shown that). When a plurality of dots recorded in different printing modes are not adjacent to each other in this manner, high-resolution data (small dot) is placed in an adjacent portion of the target pixel d and adjacent high-resolution data dx recorded in a different printing mode. The complementary dots dy are arranged at all the points where can be arranged. In FIG. 4A, five small dots dy of the same number as dx are respectively arranged on high resolution 720 dpi grid points.

Next, as shown in FIG. 4B, when the image data recorded in different print modes is a plurality of dot rows (not the number of touching dots), the dot row (the star mark in FIG. 4) is used. The dot arrangement in the print mode change unit is determined in consideration of the directionality (two dots shown). A line segment perpendicular to a line segment connecting the centers of two dots d and dd which are high-resolution data (solid line downwardly sloping in the figure) is set so as to pass through the current pixel of interest d, and printing that does not include this line segment A complementary dot dy is arranged on the boundary of the mode change portion. In FIG. 4B, three dys are arranged at the boundary. In actuality, such complementary dot position detection is performed by, for example, pattern matching. In the case of FIG. 4B, there are eight types of the above-mentioned line segments with respect to the target pixel d, and it is sufficient to detect whether or not they match around the current target pixel.

FIG. 5A shows dot complementation at the boundary of a print mode change portion recorded in the same raster in different print modes by the above-described method. A portion indicated by a black circle is the complementary dot group dy described with reference to FIG. FIG. 5B is a diagram that makes it easier to see the dot arrangement situation. Compared to FIG. 11B, the effect of dot complement can be seen.

Further, as another change of the recording condition for improving the image, as shown in FIG. 11, the gap B due to the dislocation of the grid point of the dot arrangement and the density although very partially The problem can also be solved by changing data formed by relatively high-resolution small dots in any area of the emphasis area C to low-resolution data of large dots, and recording adjacent areas of different resolutions with large dots. .

(Third Embodiment) In this embodiment, the dot arrangement in the high-density recording mode is made different by the ejection frequency of the print head as the type of print mode or the scanning speed of the carriage on which the print head is mounted and moved. Performs typical printing. When printing low-resolution data shown in FIG. 6A in the high-density recording mode, the arrangement of the recording data differs depending on the performance of the print head configuration, ink ejection frequency, and the like. In other words, there is a limit to the ink ejection frequency, and therefore, when printing at high density, there is a limit to the continuous arrangement of ink droplets (particularly in the main scanning direction). When the print head shown in FIG. 17B is used, the dot arrangement is performed continuously in the main scanning direction by lowering the carriage scanning speed. Since the printing speed is reduced by that amount, high-resolution printing is performed so that the printing speed does not decrease, but the dot arrangement is such that the ejection frequency does not become higher than during low-resolution printing, and is arranged in the half pixel sub-scanning direction as shown in FIG. There is a dot arrangement method. If this dot arrangement is used, the ink discharge in the main scanning direction has the same frequency at the time of high-resolution printing as at the time of low-resolution printing, so that printing can be performed without lowering the carriage speed.

FIG. 6C shows an example in which the dot position is changed in the situation of adjacent pixels in order to improve the image quality of the oblique line component in FIG. 6B. In this example, the target pixel is set as a dot on a low-resolution grid point (a circle d shaded in the figure).
b) Dots da (gray circles) are arranged in the existing direction only when image data exists at the low resolution grid points in the oblique direction. If there is no adjacent pixel in the oblique direction, a dot da is arranged at the lower right. Further, in a single part of a continuous image, no complementary dot subjected to high resolution conversion is arranged as shown in FIG. The dot da is arranged at the lower right of the isolated point. As described above, by arranging the high-resolution complementary pixels only in the diagonal diagonal direction with respect to the low-resolution grid points, printing can be performed without increasing the ink ejection frequency in the main scanning direction. Next, the recording in FIG. 6D will be described. In this example, since the printing mode is the high-quality priority printing mode, the carriage moving speed is set to about the value for low-resolution printing so that the ink ejection frequency does not exceed the upper limit of the print head. It is reduced by half, and high-resolution printing is also performed in the main scanning direction. In such an image quality priority print mode, the dots d are also used in the main scanning direction.
Both a and dot db perform a dot arrangement that enables continuous recording at high resolution.

Next, as shown in FIG. 17 (a), when a print head which is shifted by a half pixel (= high resolution recording density) in the sub-scanning direction is separately provided, the dot da shown in FIG.
(Gray circle) is also a single color, but can be printed during the same scan. By using such a print head compatible with both high speed and high image quality, it is possible to print the dot da in FIGS. 6B and 6C during the same scan as the dot db. The same symbols in FIG. 6 are represented by the same marks (hatched patterns).

As described above, efficient image recording can be achieved by changing the arrangement of the recording dots of high-resolution data depending on the ink ejection frequency, carriage scanning speed, or the configuration of the print head as a difference in the print mode.

(Fourth Embodiment) This embodiment achieves an improvement in print quality of overprinting in which the same image data is printed a plurality of times in the same pixel in order to improve the print density. In the present embodiment, the print data arranged per low-resolution unit pixel during double-printing of low-resolution data shown in FIG. 7A is doubled. At this time,
The data is converted into high-resolution data, and four small dots are arranged per unit lattice (large dots at low resolution are shown in FIG. 7B).
Is usually recorded with two small dots at a high resolution.) As described above, by converting dots twice as large as the normal ink ejection amount to a high resolution, the contours and corners of the image are formed at a high resolution. FIG. 8A shows the dots db (original data) arranged at the low resolution grid points and the dots da arranged to increase the ink ejection amount. In the figure, the dots da are not arranged exactly in the vicinity because the dots da are not arranged in the vicinity where the lattice point dots db are not adjacent to each other. In the next step, the corner portion of the image data is corrected to correct the outline portion. As shown in FIG. 8 (b), focusing on only the lattice point dots db, dots df (white circles) are formed at the L-shaped corners.
Is added, and the dot “de” (small black circle) at the corner is deleted. The dot df is added before the deletion of the dot de. The addition of the dot df is determined by or after the high-resolution conversion and after the additional sequence, and the dot arrangement is determined by either of the detections, and it is not necessary to overlap the dots df and print at the same position. As described above, dots are arranged so as to increase the ink ejection amount per unit pixel at the time of high-resolution data conversion, and then smoothing processing such as smoothing is performed. As a result, as shown in FIG. No image degradation occurs at the edge even if the shot is performed. The effect of the above processing can be understood from the comparison with FIG.

FIG. 9 shows an example in which four small dots in the high resolution are always arranged for one large dot in the low resolution, and the smoothing process (FIG. 9B) is performed. Since all the supplementary dots are arranged at the time of high-resolution conversion, the above-described smoothing process only needs to reduce the dots de. Although the corners are more conspicuous than the example of FIG. 8, there is an advantage that the smoothing process is simple because only the dot reduction is performed.

FIG. 32 is a block diagram showing the features of the present invention.

In FIG. 32, when data is input to the "reception buffer", the resolution of the recording data is converted by the "resolution conversion means". Here, the number and position of uniform dots are developed from the original image data. Next, this boundary portion, which is the resolution change portion, is detected by "AorB resolution print mode adjacent portion determination means". Here, it is determined whether or not there is an adjacent area of the different resolution print modes A and B. In addition, the resolution, the print mode, the recording medium,
The determination is made based on the settings of the recording data and the recording means such as the selected print head. Next, the color data of the adjacent area is detected by using “color data determining means of the adjacent area”.
In this color data determination, the color data of the adjacent area, such as the color of the A resolution print mode portion, the color of the B resolution print mode portion, and the color of the background portion, are checked.

Then, the recording data (color, ink ejection amount, printing mode, etc.) to be actually recorded in the adjacent area or the like is determined by the "improvement means of image quality in the adjacent area". If adjacent colors are only the same color, print dots before and after resolution conversion are determined according to the recording medium, and image quality improvement such as addition and reduction is performed according to the amount of shot before and after resolution conversion. In the previous embodiment, an excellent case is shown when the recording medium has a small amount of ink bleeding. However, when the ink bleeding is large like plain paper, a large number of high-density areas are generated rather. In some cases, it is preferable to thin out high-resolution ink dots or low-resolution ink dots in consideration of ink bleeding, rather than to compensate for the ink dots. If the adjacent colors are only different single colors (one ink color), the color of each resolution print mode area is added to or reduced in each area. If multi-valued color data or a background color exists in the adjacent colors, the color is changed so that the tint change is reduced. After these steps, the print data is determined by the "print data determination means", and the operation can be shifted to the recording operation.

In FIG. 32, the main part of the above embodiment has been clarified. However, in any case, the present invention provides an ink jet recording apparatus capable of performing recording with different resolutions which has not been recognized or suggested conventionally. In this method, it is possible to reliably prevent the failure of an ink-recorded image caused by a change in resolution, and thus it is possible to form various types of recording (general term for printing, printing, etc.) with high quality.

In each of the embodiments described above, the present invention will be described by taking the ink jet recording apparatus shown in FIG. 18 as an example. The ink jet recording apparatus shown in FIG. However, the present invention is not limited to the above-described recording apparatus but can be widely applied. Hereinafter, the configuration of the recording apparatus that can implement the present invention will be supplemented.

FIG. 12 shows another example to which the present invention can be applied, and is 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 at the sheet feeding position of No. 0 is conveyed to a 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 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). 10
Reference numeral 7 denotes a switch and a display panel for displaying various recording mode settings and the status of the recording apparatus.

FIG. 13 is a perspective view of a recording head unit. A black ink tank 21 for storing black ink and a color ink tank 20 for integrally storing the other three color inks are connected to a print head 102 by pipes, respectively. Supplied to 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 of this embodiment, an electric / heat converter is arranged corresponding to the liquid path (nozzle) of the ink, and a drive signal corresponding to the recording information is applied to the electric / heat converter. That is, a so-called bubble jet recording method in which ink is ejected from the printer is adopted.

FIG. 14 is an enlarged sectional view of the vicinity of the electrothermal transducer of the recording head, and FIG. 15 is an enlarged front view of the vicinity of the electrothermal transducer of the recording head.

As shown in FIG. 15, the heating element 30, which is an electric-to-heat converter of the recording head, has two heating elements H1 and H1, each of which can independently generate heat for all nozzles.
2 are 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 has been rapidly heated by the heat generated by the heating elements H1 and H2, forms bubbles by film boiling, and the ink droplet 35 is ejected toward the recording medium 31 as shown in FIG. Then, characters and images are formed on a recording medium. In this case, the volume of each color ink droplet to be ejected is about 40 ng.

On the other hand, at the time of 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 at the time of 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. Behind the portion where the ink liquid path is provided, a common liquid for supplying ink to these liquid paths is provided. A chamber 32 is provided. Heating elements 30 (H1, H2 shown in FIG. 15), which are electrothermal converters that generate heat energy used to discharge 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,
The heating element 30 and the electrode wiring are formed on a substrate 33 made of silicon or the like.
It is formed thereon 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, the recording head using the electrothermal transducer uses bubbles formed by applying thermal energy at the time of ejecting ink droplets, and is therefore generally called a bubble jet recording head.

The present invention particularly provides an excellent effect in a recording apparatus using an ink jet type recording head for performing recording by forming a flying liquid by utilizing thermal energy among ink jet recording methods.

The typical configuration 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 includes 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.

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 on which a recording apparatus can record. 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 integrally formed 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 connection with the apparatus main body or the ink from the apparatus main body is attached to 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 provided integrally with the recording head itself is used.

Further, 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.

Further, 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.

In all the above embodiments, the changed portion of the recording image type is effective before and after the change when the same single color or a different single color is used, and when the recorded image is changed from the secondary color to the secondary color. If there is a different color data in the background or in the background, the above-mentioned embodiment is not effective, and there is a possibility that a change in tint may occur.

The relative low resolution in the embodiment is 360
dpi and high resolution were set to 720 dpi, but not limited to this, for example, 300 and 600 dpi, 400 and 800 dpi
The effect of the present invention is effective even with the combination of i. The magnitude ratio of the ink droplets or the ejection amount itself is also effective in addition to the values in the text. Although bidirectional printing has been described as a printing method, the present invention is also effective in printing scanning in only one direction. In addition, although the printing mode switching according to the type of recording image has been described assuming that a black image is printed at high density, a color image may be printed at high density depending on the purpose of image output. That is, although the criteria vary depending on the purpose, the effect of the present invention itself is effective.

The dot arrangement of different resolutions in the embodiment mainly shows the case where the lower resolution (large dot) is moved diagonally to the lower right in the drawing. It can be arranged without limitation. In this case, the gap portion of the image described in the embodiment occurs only in a different direction, and the effect of the present invention is still effective.

[0093]

According to the present invention, low resolution images can be handled.
When recording a low-resolution image based on the specified grid point
Grid points on the grid points when recording high-resolution images.
To record high-resolution and low-resolution images
Images with different resolutions are adjacent
The formation of dots in the area is controlled and the solution
Image omission and density occurring between images with different image densities
Can suppress the emphasis and achieve good image recording
You.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a dot arrangement according to a first embodiment.

FIG. 2 is a diagram showing another recording method according to the first embodiment.

FIG. 3 is a diagram illustrating another dot arrangement example of the first embodiment.

FIG. 4 is a diagram showing a second embodiment.

FIG. 5 is a diagram illustrating a dot arrangement according to a second embodiment.

FIG. 6 is a diagram showing a third embodiment.

FIG. 7 is a diagram showing conventional overprinting.

FIG. 8 is a diagram showing a fourth embodiment.

FIG. 9 is a diagram showing another example of the fourth embodiment.

FIG. 10 is a diagram showing a conventional recording image changing unit.

FIG. 11 is a diagram illustrating a conventional recording image changing unit.

FIG. 12 is a perspective view of an ink jet recording apparatus applicable to the present invention.

FIG. 13 is a perspective view of a recording head unit.

FIG. 14 is an enlarged sectional view of a recording head.

FIG. 15 is an enlarged cross-sectional view showing the arrangement of a heater serving as a discharge unit of a recording head.

FIG. 16 is a diagram showing details of a recording head using a piezo element as an ejection unit.

FIG. 17 is a diagram showing a configuration in which a black head is shifted by half a pixel and a conventional print head.

FIG. 18 is a diagram showing an ink jet recording apparatus applied to the present invention.

FIG. 19 is a diagram showing a dot arrangement indicating high speed (low-resolution recording).

FIG. 20 is a diagram showing a dot arrangement indicating high-density recording in the main scanning direction.

FIG. 21 is a diagram showing a dot arrangement indicating high density (high-resolution recording).

FIG. 22 is a diagram illustrating one-pass bidirectional printing.

FIG. 23 is a diagram showing two-pass bidirectional printing (high-density recording only in the main scanning direction).

FIG. 24 is a diagram illustrating a printing method for performing high-density recording in both main scanning and sub-scanning.

FIG. 25 is a diagram showing combinations of recording image types.

FIG. 26 is an explanatory diagram showing a multi-pass printing method.

FIG. 27 is an explanatory diagram showing a multi-pass printing method.

FIG. 28 is an explanatory diagram showing a multi-pass printing method.

FIG. 29 is an explanatory diagram showing a multi-pass printing method.

FIG. 30 is a flowchart applicable to the present invention.

FIG. 31 is a flowchart applicable to the present invention.

FIG. 32 is a functional block diagram for explaining the device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Print head 2 Discharge roller 4 Carriage shaft 6 Belt 8 Carriage motor 9 Cable 10 Ink tank 400 Print head recovery device 420 Protective cap

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Norifumi Koitabashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Masao Kato 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Sadayuki Sugama 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-6-143618 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B41J 2/01 B41J 2/485 B41M 5/00

Claims (11)

(57) [Claims] 1. An ink-jet recording method for recording an image on a recording medium by using an ink-jet head for discharging ink and discharging ink from the ink-jet head onto grid points corresponding to resolution to form dots. based on the lattice points corresponding to the low resolution image, the grid point in recording low-resolution image, and the upper grid point for recording an image of high resolution, when recording an image of the high resolution Dot size
Is used to record the low-resolution image.
Recording with a size smaller than the size of the
Change the resolution from a low-resolution image to a high-resolution image according to the resolution change when recording the image on the recording medium.
Originating in flanking regions at the time of, the images with different resolutions are adjacent
An ink jet recording method, which performs recording by supplementing dots in a white area of a generated image . 2. The ink jet recording method according to claim 1, wherein the white area is recorded by supplementing dots on grid points corresponding to the high resolution image. 3. Resolution is recorded when an image is recorded on a recording medium.
When changing the resolution from a high-resolution image to a low-resolution image according to the degree of change, images with different resolutions are adjacent.
The method according to claim 1, wherein the printing is performed by thinning out dots to be formed in adjacent areas. 4. The data corresponding to a dot formed in printing the high-resolution image is generated based on data corresponding to a dot formed in printing the low-resolution image. 2. The inkjet recording according to claim 1, wherein the control of the formation is to change the arrangement of the dots when converting the data corresponding to the low resolution into the data corresponding to the high resolution according to the data. Method. 5. The data corresponding to a dot formed in printing the high-resolution image is generated based on data corresponding to a dot formed in printing the low-resolution image, and Control of formation
It is characterized by converting data corresponding to low resolution into data corresponding to high resolution, further changing the dot arrangement for performing density enhancement recording according to the data, and performing partial addition and partial deletion. The inkjet recording method according to claim 1. 6. An ink jet recording apparatus for recording an image on a recording medium by using an ink jet head for discharging ink and discharging ink from the ink jet head onto grid points corresponding to resolution to form dots. On the basis of the grid point corresponding to the low-resolution image, a means for recording grid points when recording a low-resolution image as grid points when recording a high-resolution image, and according to the resolution When recording the high resolution image
The size of the dot to be formed on the
Relatively smaller than the size of the dots formed when recording
Discharge from the inkjet head so that
Control means for changing the amount of ejected ink droplets; means for determining an adjacent area where images of different resolutions are adjacent to each other in accordance with a change in resolution when printing an image on a print medium ; Based on the results, do you have a lower resolution image?
When changing the resolution to a higher resolution image.
White area of an image generated in the adjacent area where an image becomes adjacent
An ink jet recording apparatus comprising: means for performing recording by supplementing dots in an area . Wherein said white area to ink jet recording apparatus according to claim 6, characterized in that recording is performed supplemented with dots on the high-resolution grid points corresponding to the image of. 8. The ink jet recording apparatus according to claim 6 , wherein when changing the resolution from a high- resolution image to a low-resolution image, printing is performed by thinning out dots to be formed in the adjacent areas. . 9. The apparatus according to claim 6 , further comprising means for determining whether or not the image to be recorded is a character, and recording the character as the high-resolution image in accordance with a result of the determination. The inkjet recording apparatus according to any one of the preceding claims. 10. An image processing apparatus further comprising: means for determining whether an image to be recorded is a black image or a color image, and according to whether the image to be recorded is the black image or the color image, The inkjet recording apparatus according to claim 6 , wherein the resolution is changed. Wherein said ink jet head, an ink jet recording apparatus according to any one of claims 6 to 10, characterized in that the thermal energy is applied to ink to eject the ink.